ROR1/PTK7 BI-SPECIFIC ANTIGEN BINDING MOLECULES FIELD OF INVENTION The present invention relates to bi-specific antigen binding molecules with specificity for both receptor tyrosine kinase-like orphan receptor 1 (ROR1) and inactive protein tyrosine kinase 7 (PTK7, CCK4) and associated fusion proteins and conjugates. In a further aspect, the present invention relates to conjugated immunoglobulin-like shark variable novel antigen receptors (VNARs). BACKGROUND Receptor tyrosine kinase-like orphan receptor 1 (ROR1) is a 937 amino acid glycosylated type I single pass transmembrane protein. The extracellular region consists of three distinct domains composing an N-terminal immunoglobulin domain (Ig), followed by a cysteine rich fizzled domain (fz) which in turn is linked to the membrane proximal kringle domain (kr). The intracellular region of the protein contains a pseudo kinase domain followed by two Ser/Thr rich domains which are interspersed by a proline-rich region, and this same overall domain architecture is conserved in the closely related family member ROR2, with which it shares high sequence identity. ROR1 is expressed during embryonic development, where it is prominently expressed in neural crest cells and in the necrotic and interdigital zones in the later stages of development. However, its expression is quickly silenced after birth, and is largely absent in normal adult tissue. ROR1 expression has been observed at both the mRNA and protein level across a broad range of solid tumours and haematological malignancies including lung, endometrial, pancreatic, ovarian, colon, head and neck and prostate cancers, melanoma and renal cell carcinoma, breast cancer and chronic lymphocytic leukemia (CLL) and acute lymphoblastic leukemia (AML). Additionally, increased ROR1 expression is reported to correlate with poor clinical outcomes for a number of cancer indications including breast cancer, ovarian cancer, colorectal cancer, lung adenocarcinoma and CLL. Consistent with ROR1’s expression pattern and the link to poor clinical prognosis, a functional role for ROR1 in tumorigenesis and disease progression has been demonstrated for a number of different cancer indications. ROR1 promotes epithelial-mesenchymal transition and metastasis in models of breast cancer and spheroid formation and tumour engraftment in models of ovarian cancer. ROR1 is a transcript target of the NKX2-1/TTF-1 lineage survival factor oncogene in lung adenocarcinoma, where it sustains EGFR signalling and represses pro-apoptotic signalling and an EGF induced interaction between ROR1 and EGFR has been observed. Co-expression of EGFR and ROR1 mRNA has been noted from breast cancer gene expression database mining. ROR1 has also been shown to act as a scaffold to sustain caveolae structures and by-pass signalling mechanism that confer resistance to EGFR tyrosine kinase inhibitors. Signalling through an ROR1-HER3 complex modulates the Hippo-YAP pathway and promotes breast cancer bone metastasis and the protein can promote Met-driven tumorigenesis. ROR1 expression is associated with chemotherapy resistance in breast cancer through activation of Hippo-YAP/TAZ and BMI1 pathways. Whilst in CLL, ROR1 has been reported to hetero- oligomerise with ROR2 in response to Wnt5a to transduce signalling and enhance proliferation and migration. Given the functional role of ROR1 in cancer pathology and the general lack of expression on normal adult tissue, this oncofetal protein is an attractive target for cancer therapy. Antibodies to ROR1 have been described in the literature WO2021097313 (4A5 kipps), WO2014031174 (UC961), WO2016187220 (Five Prime) WO2010124188 (2A2), WO2012075158 (R11, R12), WO2011054007 (Oxford Bio), WO2011079902 (Bioinvent) WO2017127664, WO2017127664 (NBE Therapeutics, SCRIPPS), WO2016094847 (Emergent), WO2017127499), and a humanised murine anti-ROR1 antibody, UC961, has entered clinical trials for relapsed or refractory chronic lymphocytic leukemia. Chimeric antigen receptor T-cells targeting ROR1 have also been reported (Hudecek M et al, Clin. Cancer Res., 2013, 19, 3153-64) and preclinical primate studies with UC961 and with CAR-T cells targeting ROR1 showed no overt toxicity, which is consistent with the general lack of expression of the protein on adult tissue (Choi M et al, Clinical Lymphoma, myeloma & leukemia, 2015, S167; Berger C et al, Cancer Immunol. Res., 2015, 3, 206). PTK7 (CCK4) is a protein comprising an extracellular domain with seven immunoglobulin like domains a transmembrane domain and a catalytically defective tyrosine kinase and is thus categorised as a pseudokinase. Overexpression of PTK7 has been documented in multiple solid tumours and may be associated with a worse prognosis (for example epithelial ovarian cancer, esophageal adenocarcinoma). RNA-seq data from the cancer genome atlas reports increased PTK7 mRNA levels in various cancer tissues including endometrial, head and neck, lung, ovary, cervical, prostate, breast, pancreatic, bladder, thyroid, and esophageal cancers when compared with the overall mean level from normal tissues (Shin WS et al Sci Reports, 2018, 8, 8519). IHC staining of primary human tumours shows overexpression of PTK7 across a number of cancer indications including ovarian cancer, TNBC, NSCLC. PTK7 expression is also enriched on tumour initiating cells (Damelin M et al, Sci Transl. Med., 2017, 9, 1-11. doi: 10.1126/scitranslmed.aag2611) and shedding of the extracellular domain of PTK7 has been reported in cancer patients form a number of indications (US2015315293). PTK7 is also expressed on a number of normal human tissues including eosophagus, kidney, urinary bladder and lung. Although PTK7 does not play a role in the biology of mature cells it has been linked with regulating planar cell polarity (PCP) and canonical and non-canonical Wnt signaling during organ development through interactions with a non-canonical Wnt/PCP ligand, Wnt5A, ^. Wnt receptors such as Fz7 and LRP6 and intracellular Wnt signaling proteins such as Dvl and β-catenin (Peradziryi et al.2011) and ROR2 (Martinez et al.2015. J. Biol. Chem.209, 30562-72). Preclinical studies suggest that phosphorylation of a functional PTK7 may influence cancer cell biology and aggressiveness. In vitro studies suggest that PTK7 signalling increases the proliferation, survival, migration, and invasion of cancer cells through activation of ERK, JNK, p38, and NF-κB signaling pathways, whereas it decreases apoptosis through suppression of caspase-9 and -10. PTK7 activation also increases angiogenesis through activation of FLT1. The expression pattern and potential functional role of PTK7 in various cancers makes it an attractive therapeutic target. Antagonist monoclonal antibodies have been developed to inhibit the function of PTK7 in tumorigenesis and antibody drug conjugate targeting PTK7 has entered clinical trials (ADC). This ADC, Cofetuxumab Pelidotin, consists of a humanised mouse anti-PTK7 monoclonal antibody (hu24) conjugated with an auristatin 0101 payload, via mc-valine-citrulline-PABC linker, using endogenous cysteine residues. Single domain binding molecules can be derived from an array of proteins from distinct species. The immunoglobulin isotope novel antigen receptor (IgNAR) is a homodimeric heavy-chain complex originally found in the serum of the nurse shark (Ginglymostoma cirratum) and other sharks and ray species. IgNARs do not contain light chains and are distinct from the typical immunoglobulin structure. Each molecule consists of a single-variable domain (VNAR) and five constant domains (CNAR). The nomenclature in the literature refers to IgNARs as immunoglobulin isotope novel antigen receptors or immunoglobulin isotope new antigen receptors and the terms are synonymous. There are three main defined types of shark IgNAR known as I, II and III (Kovalena et al, Exp Opin Biol Ther 201414(10) 1527-1539). These have been categorized based on the position of non-canonical cysteine residues which are under strong selective pressure and are therefore rarely replaced. All three types have the classical immunoglobulin canonical cysteines at positions 35 and 107 that stabilize the standard immunoglobulin fold, together with an invariant tryptophan at position 36. There is no defined CDR2 as such, but regions of sequence variation that compare more closely to TCR HV2 and HV4 have been defined in framework 2 and 3 respectively. Type I has germline encoded cysteine residues in framework 2 and framework 4 and an even number of additional cysteines within CDR3. Crystal structure studies of a Type I IgNAR isolated against and in complex with lysozyme enabled the contribution of these cysteine residues to be determined. Both the framework 2 and 4 cysteines form disulphide bridges with those in CDR3 forming a tightly packed structure within which the CDR3 loop is held tightly down towards the HV2 region. To date Type I IgNARs have only been identified in nurse sharks – all other elasmobranchs, including members of the same order have only Type II or variations of this type. Type II IgNAR are defined as having a cysteine residue in CDR1 and CDR3 which form intra-molecular disulphide bonds that hold these two regions in close proximity, resulting in a protruding CDR3 that is conducive to binding pockets or grooves. Type I sequences typically have longer CDR3s than type II with an average of 21 and 15 residues respectively. This is believed to be due to a strong selective pressure for two or more cysteine residues in Type I CDR3 to associate with their framework 2 and 4 counterparts. Studies into the accumulation of somatic mutations show that there are a greater number of mutations in CDR1 of type II than type I, whereas HV2 regions of Type I show greater sequence variation than Type II. This evidence correlates well with the determined positioning of these regions within the antigen binding sites. A third IgNAR type known as Type III has been identified in neonates. This member of the IgNAR family lacks diversity within CDR3 due to the germline fusion of the D1 and D2 regions (which form CDR3) with the V-gene. Almost all known clones have a CDR3 length of 15 residues with little or no sequence diversity. Another structural type of VNAR, termed type (IIb or IV), has only two canonical cysteine residues (in framework 1 and framework 3b regions). So far, this type has been found primarily in dogfish sharks and was also isolated from semisynthetic V-NAR libraries derived from wobbegong sharks. ROR1-specific antigen binding molecules, including VNARs, are described in WO 2019/122447, hereby incorporated by reference in its entirety. Amongst others, WO 2019/122447 describes the sequences of B1, P3A1 and P3A1 G1 identified below. B1 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPWLVQWYDGAGTVLTVN (SEQ ID NO: 113) P3A1 TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVN (SEQ ID NO: 206) P3A1 G1 TRVDQSPSSLSASVGDRVTITCVLTDTSYGLYSTYWYRKNPGSSNKEQISISGRYSESVN KGTKSFTL TISSLQPEDSATYYCRAREARHPWLRQWYDGAGTKVEIK (SEQ ID NO: 114). WO 2019/122445 describes ROR1/EGFR bi-specific binding molecules where the ROR1 binding molecules are as described in WO 2019/122447, however ROR1/PTK7 bi-specific binding molecules are not disclosed. Conjugates of ROR1-specific antigen binding molecules, including VNARs, are described in WO 2020/254640, hereby incorporated by reference in its entirety. WO 2020/254640 describes anthracycline (PNU) derivatives suitable for use in drug conjugates. Specifically, derivatives of PNU159682 are provided, which lack the C14 carbon and attached hydroxyl functionality, and in which an ethylenediamino (EDA) group forms part of a linker region between the C13 carbonyl of PNU159682 and a maleimide group. Alternatively, the same molecules may be described with EDA-PNU as the “warhead” such that the EDA group is not considered part of the linker region. Where the linker comprises val-cit-PAB the maleimide group may be replaced with any reactive group suitable for a conjugation reaction. Such payloads are able to react with a free thiol group on another molecule. Where the free thiol is on a protein a protein-drug conjugate (PDC) may be formed. The anthracycline derivative PNU-159682 has been described as a metabolite of nemorubicin and has been reported to exhibit extremely high potency for in vitro cell killing in the pico- to femtomolar range with one ovarian (A2780) and one breast cancer (MCF7) cell line (WO2012/073217 A1). Derivatives of PNU-159682 have also been described in WO2016/102679. Conjugation of PNU-159682 derivatives to antibodies is described in WO2009/099741, WO2016/127081 and WO2016/102679, Yu et al, Clin. Cancer Res 2015, 21, 3298 and Stefan et al, Mol. Cancer. Ther., 2017, 16,879. Auristatin E (AE) and monomethylauristatin E (MMAE) are synthetic analogs of the dolastatins, a special group of linear pseudopeptides originally isolated from marine sources, some of which have very potent cytotoxic activity against tumour cells. However, MMAE has the disadvantage of a comparatively high systemic toxicity. To improve the tumour selectivity MMAE is used in particular in conjunction with enzymatically cleavable valine citrulline linkers in the ADC setting for more targeted tumour therapy (see for example WO 2005/081711. After proteolytic cleavage, MMAE is preferably released intracellularly from corresponding ADCs. Monomethylauristatin F (MMAF) is an auristatin derivative having a C- terminal phenylalanine moiety. MMAF as well as various ester and amide derivatives thereof have been disclosed in WO 2005/081711. Further auristatin analogues with a C-terminal, amidically substituted phenylalanine unit are described in WO 01/18032. WO 02/088172 and WO 2007/008603 which claim MMAF analogs which relate to side-chain modifications of phenylalanine, and in WO 2007/008848 those in which the carboxyl group of the phenylalanine is modified. Auristatin conjugates linked via the C- terminus have been described in WO 2009/117531 and further conjugates are described in WO2013/087716. ROR1-specific variant antigen binding molecules having improved properties and conjugates thereof to derivatives of PNU-159682 are described in PCT/EP2021/086667, filed on 17 December 2021, which is hereby incorporated by reference in its entirety. PCT/EP2021/086667 does not disclose any bi- specifics comprising a ROR1-specific variant antigen binding molecule of PCT/EP2021/086667 and an PTK7-specific variant antigen binding molecule. SUMMARY OF INVENTION The present invention generally relates to bi-specific antigen binding molecules. Specifically, the present invention relates to bi-specific molecules having the ability to bind to both ROR1 and PTK7. In a first configuration, the invention provides a PTK7-specific binding molecule as disclosed in relation to any of the following aspects of the invention. According to a first aspect, the invention provides a bi-specific antigen binding molecule comprising: (i) a receptor tyrosine kinase-like orphan receptor 1 (ROR1) specific antigen binding molecule comprising an amino acid sequence represented by the formula (I): FW1-CDR1-FW2-HV2-FW3a-HV4-FW3b-CDR3-FW4 (I) wherein CDR3 is a CDR sequence having an amino acid sequence selected from the group consisting of YPWGAGAPYNVQWY (SEQ ID NO: 23), YPWGAGAPYLVQWY (SEQ ID NO: 20), YPWGAGAPWNVQWY (SEQ ID NO: 24), YPSGAGAPRPVQWY (SEQ ID NO: 11), YPWGAGAPCLVQWY (SEQ ID NO: 12), YPWGAGAPRLVQWY (SEQ ID NO: 13), YPWGAGAPRQVQWY (SEQ ID NO: 14), YPWGAGAPRSVQWY (SEQ ID NO: 15), YPWGAGAPSLVQWY (SEQ ID NO: 16), YPWGAGAPSNVQWY (SEQ ID NO: 17), YPWGAGAPSQVQWY (SEQ ID NO: 18), YPWGAGAPSSVQWY (SEQ ID NO: 19), YPWGAGAPWQVQWY (SEQ ID NO: 21), YPWGAGAPWSVQWY (SEQ ID NO: 22), and YPWGAGAPWLVQWY (SEQ ID NO: 10); CDR1 is a CDR sequence having an amino acid sequence selected from the group consisting of GANYGLAA (SEQ ID NO: 1), DANYGLAA (SEQ ID NO: 5), GANYDLSA (SEQ ID NO: 2), GANYGLSA (SEQ ID NO: 3), and GANYDLAA (SEQ ID NO: 4) FW1 is a framework region; FW2 is a framework region; HV2 is a hypervariable sequence having an amino acid sequence selected from the group consisting of SSNQERISIS (SEQ ID NO: 6), and SSNKERISIS (SEQ ID NO: 7); FW3a is a framework region; HV4 is a hypervariable sequence having an amino acid sequence selected from the group consisting of NKRTM (SEQ ID NO: 8) and NKGTM (SEQ ID NO: 9); FW3b is a framework region; FW4 is a framework region; wherein if CDR3 is YPWGAGAPWLVQWY (SEQ ID NO: 10) then CDR1 is selected from the group consisting of DANYGLAA (SEQ ID NO: 5), GANYGLSA (SEQ ID NO: 3) and GANYDLAA (SEQ ID NO: 4); and (ii) a protein tyrosine kinase 7 (PTK7) specific antigen binding molecule. According to a second aspect, the invention provides a bi-specific antigen binding molecule comprising: (i) a receptor tyrosine kinase-like orphan receptor 1 (ROR1) specific antigen binding molecule comprising an amino acid sequence represented by the formula (I): FW1-CDR1-FW2-HV2-FW3a-HV4-FW3b-CDR3-FW4 (I) wherein CDR1 is a CDR sequence having an amino acid sequence selected from the group consisting of GTRYGLYS (SEQ ID NO: 25), GTRYGLYSS (SEQ ID NO: 26), DTRYALYS (SEQ ID NO: 27), DTRYALYSS (SEQ ID NO: 28), GTKYGLYA (SEQ ID NO: 29), GTKYGLYAS (SEQ ID NO: 30) and DTSYGLYS (SEQ ID NO:207); FW1 is a framework region; FW2 is a framework region; HV2 is a hypervariable sequence having an amino acid sequence selected from the group consisting of SSDEERISIS (SEQ ID NO: 31), STDEERISIG (SEQ ID NO: 32), SPNKDRMIIG (SEQ ID NO: 33), STDKERIIIG (SEQ ID NO: 34) and TTDWERMSIG (SEQ ID NO:208); FW3a is a framework region; HV4 is a hypervariable sequence having an amino acid sequence selected from the group consisting of NKGTK (SEQ ID NO: 35), NKGSK (SEQ ID NO: 36), NNGTK (SEQ ID NO: 37), NNRSK (SEQ ID NO: 38) and NKGAK (SEQ ID NO:209); FW3b is a framework region; CDR3 is a CDR sequence having an amino acid sequence according to REARHPWLRQWY (SEQ ID NO: 39); FW4 is a framework region; and (ii) a protein tyrosine kinase 7 (PTK7) specific antigen binding molecule. According to a third aspect, the invention provides a recombinant fusion protein comprising a bi- specific antigen binding molecule according to the first or the second aspects of the invention. According to a fourth aspect, the invention provides a recombinant fusion protein dimer comprising: (a) a first recombinant fusion protein, wherein the first recombinant fusion protein comprises a receptor tyrosine kinase-like orphan receptor 1 (ROR1) specific antigen binding molecule comprising an amino acid sequence represented by the formula (I): FW1-CDR1-FW2-HV2-FW3a-HV4-FW3b-CDR3-FW4 (I) wherein CDR3 is a CDR sequence having an amino acid sequence selected from the group consisting of YPWGAGAPYNVQWY (SEQ ID NO: 23), YPWGAGAPYLVQWY (SEQ ID NO: 20), YPWGAGAPWNVQWY (SEQ ID NO: 24), YPSGAGAPRPVQWY (SEQ ID NO: 11), YPWGAGAPCLVQWY (SEQ ID NO: 12), YPWGAGAPRLVQWY (SEQ ID NO: 13), YPWGAGAPRQVQWY (SEQ ID NO: 14), YPWGAGAPRSVQWY (SEQ ID NO: 15), YPWGAGAPSLVQWY (SEQ ID NO: 16), YPWGAGAPSNVQWY (SEQ ID NO: 17), YPWGAGAPSQVQWY (SEQ ID NO: 18), YPWGAGAPSSVQWY (SEQ ID NO: 19), YPWGAGAPWQVQWY (SEQ ID NO: 21), YPWGAGAPWSVQWY (SEQ ID NO: 22), and YPWGAGAPWLVQWY (SEQ ID NO: 10); CDR1 is a CDR sequence having an amino acid sequence selected from the group consisting of GANYGLAA (SEQ ID NO: 1), DANYGLAA (SEQ ID NO: 5), GANYDLSA (SEQ ID NO: 2), GANYGLSA (SEQ ID NO: 3), and GANYDLAA (SEQ ID NO: 4) FW1 is a framework region; FW2 is a framework region; HV2 is a hypervariable sequence having an amino acid sequence selected from the group consisting of SSNQERISIS (SEQ ID NO: 6), and SSNKERISIS (SEQ ID NO: 7); FW3a is a framework region; HV4 is a hypervariable sequence having an amino acid sequence selected from the group consisting of NKRTM (SEQ ID NO: 8) and NKGTM (SEQ ID NO: 9); FW3b is a framework region; FW4 is a framework region; wherein if CDR3 is YPWGAGAPWLVQWY (SEQ ID NO: 10) then CDR1 is selected from the group consisting of DANYGLAA (SEQ ID NO: 5), GANYGLSA (SEQ ID NO: 3) and GANYDLAA (SEQ ID NO: 4), and wherein the first antigen binding molecule is fused to a first fragment of an immunoglobulin Fc region engineered to dimerize with a second fragment of an immunoglobulin Fc region; and (b) a second recombinant fusion protein, wherein the second recombinant fusion protein comprises a protein tyrosine kinase 7 (PTK7) specific antigen binding molecule fused to a second fragment of an immunoglobulin Fc region engineered to dimerize with the first fragment of an immunoglobulin Fc region. According to a fifth aspect, the invention provides a recombinant fusion protein dimer comprising: (a) a first recombinant fusion protein, wherein the first recombinant fusion protein comprises a receptor tyrosine kinase-like orphan receptor 1 (ROR1) specific antigen binding molecule comprising an amino acid sequence represented by the formula (I): FW1-CDR1-FW2-HV2-FW3a-HV4-FW3b-CDR3-FW4 (I) wherein CDR1 is a CDR sequence having an amino acid sequence selected from the group consisting of GTRYGLYS (SEQ ID NO: 25), GTRYGLYSS (SEQ ID NO: 26), DTRYALYS (SEQ ID NO: 27), DTRYALYSS (SEQ ID NO: 28), GTKYGLYA (SEQ ID NO: 29), GTKYGLYAS (SEQ ID NO: 30) and DTSYGLYS (SEQ ID NO:207); FW1 is a framework region; FW2 is a framework region; HV2 is a hypervariable sequence having an amino acid sequence selected from the group consisting of SSDEERISIS (SEQ ID NO: 31), STDEERISIG (SEQ ID NO: 32), SPNKDRMIIG (SEQ ID NO: 33), STDKERIIIG (SEQ ID NO: 34) and TTDWERMSIG (SEQ ID NO:208); FW3a is a framework region; HV4 is a hypervariable sequence having an amino acid sequence selected from the group consisting of NKGTK (SEQ ID NO: 35), NKGSK (SEQ ID NO: 36), NNGTK (SEQ ID NO: 37), NNRSK (SEQ ID NO: 38) and NKGAK (SEQ ID NO:209); FW3b is a framework region; CDR3 is a CDR sequence having an amino acid sequence according to REARHPWLRQWY (SEQ ID NO: 39); FW4 is a framework region, and wherein the first antigen binding molecule is fused to a first fragment of an immunoglobulin Fc region engineered to dimerize with a second fragment of an immunoglobulin Fc region; and (b) a second recombinant fusion protein, wherein the second recombinant fusion protein comprises a protein tyrosine kinase 7 (PTK7) specific antigen binding molecule fused to a second fragment of an immunoglobulin Fc region engineered to dimerize with the first fragment of an immunoglobulin Fc region. In a second configuration, the invention provides a recombinant fusion protein dimer comprising (a) a first recombinant fusion protein, wherein the first recombinant fusion protein comprises a first PTK7-specific binding protein as disclosed in relation to any of the aspects of the invention and wherein the first antigen binding molecule is fused to a first fragment of an immunoglobulin Fc region engineered to dimerize with a second fragment of an immunoglobulin Fc region, and (b) a second recombinant fusion protein, wherein the second recombinant fusion protein comprises a second PTK7-specific binding protein as disclosed in relation to any of the aspects of the invention fused to a second fragment of an immunoglobulin Fc region engineered to dimerize with the first fragment of an immunoglobulin Fc region. According to a sixth aspect, the invention provides a ROR1-specific chimeric antigen receptor (CAR), comprising at least one bi-specific antigen binding molecule as defined by the first or second aspects of the invention, at least one recombinant fusion protein as defined by the third aspect of the invention, or at least one recombinant fusion protein dimer as defined by the fourth or fifth aspects of the invention, at least one PTK7 specific binding molecule as defined by the first configuration, or at least one recombinant fusion protein dimer as defined in the second or third configuration, fused or conjugated to at least one transmembrane region and at least one intracellular domain. The present invention also provides a cell comprising a chimeric antigen receptor according to the sixth aspect, which cell is preferably an engineered T-cell. In a seventh aspect of the invention, there is provided a nucleic acid sequence comprising a polynucleotide sequence that encodes a PTK7-specific binding molecule of the first configuration of the invention, or a bi-specific antigen binding molecule, recombinant fusion protein, recombinant fusion protein dimer or chimeric antigen receptor according to the first, second, third, fourth, fifth or sixth aspects of the invention, the PTK7 specific binding molecule of the first configuration, or the recombinant fusion protein dimer of the second or third configuration. There is also provided a vector comprising a nucleic acid sequence in accordance with the seventh aspect and a host cell comprising such a nucleic acid. A method for preparing a PTK7-specific binding molecule of the first configuration of the invention, the recombinant fusion protein dimer of the second or third configuration, or a bi-specific antigen binding molecule, recombinant fusion protein, recombinant fusion protein dimer or chimeric antigen receptor, of the first, second, third, fourth, fifth or sixth aspect is provided, the method comprising cultivating or maintaining a host cell comprising the polynucleotide or vector described above under conditions such that said host cell produces the bi-specific antigen binding molecule, recombinant fusion protein or chimeric antigen receptor, optionally further comprising isolating the specific antigen binding molecule, recombinant fusion protein, recombinant fusion protein dimer or chimeric antigen receptor. In an eighth aspect of the invention, there is provided a pharmaceutical composition comprising a PTK7-specific binding molecule of the first configuration of the invention, the recombinant fusion protein dimer of the second or third configuration, or the bi-specific antigen binding molecule, fusion protein, recombinant fusion protein dimer or chimeric antigen receptor of the first, second, third, fourth, fifth or sixth aspects. The pharmaceutical composition may contain a variety of pharmaceutically acceptable carriers. Pharmaceutical compositions of the invention may be for administration by any suitable method known in the art, including but not limited to intravenous, intramuscular, oral, intraperitoneal, or topical administration. In preferred embodiments, the pharmaceutical composition may be prepared in the form of a liquid, gel, powder, tablet, capsule, or foam. The bi-specific antigen binding molecule, recombinant fusion protein, recombinant fusion protein dimer or chimeric antigen receptor of the first, second, third, fourth, fifth or sixth aspects, the PTK7 specific binding molecule of the first configuration, or the recombinant fusion protein dimer of the second or third configuration may be for use in therapy. More specifically, the bi-specific antigen binding molecule, recombinant fusion protein, recombinant fusion protein dimer or chimeric antigen receptor of the first, second, third, fourth, fifth or sixth aspects may be for use in the treatment of cancer. Preferably, the cancer is a ROR1-positive cancer type and/or an PTK7-positive cancer type. More preferably, the cancer is selected from the group comprising blood cancers such as lymphomas and leukemias, chronic lymphocytic leukaemia (CLL), mantle cell lymphoma (MCL), B-cell acute lymphoblastic leukaemia (B- ALL), marginal zone lymphoma (MZL), non-Hodgkin lymphomas (NHL), acute myeloid leukemia (AML) and solid tumours including neuroblastoma, renal cancer, lung cancer, colon cancer, ovarian cancer, pancreatic cancer, breast cancer, skin cancer, uterine cancer, prostate cancer, thyroid cancer, Head and Neck cancer, bladder cancer, oesophageal cancer, stomach cancer or liver cancer. Also provided herein is the use of a bi-specific antigen binding molecule, recombinant fusion protein, recombinant fusion protein dimer or chimeric antigen receptor of the first, second, third, fourth, fifth or sixth aspects, the PTK7 specific binding molecule of the first configuration, or the recombinant fusion protein dimer of the second or third configuration in the manufacture of a medicament for the treatment of a disease in a patient in need thereof. The bi-specific antigen binding molecule, recombinant fusion protein, recombinant fusion protein dimer or chimeric antigen receptor of the first, second, third, fourth, fifth, sixth aspects, the PTK7 specific binding molecule of the first configuration, or the recombinant fusion protein dimer of the second or third configuration or pharmaceutical composition of the eighth aspect may be administered in a single dose. As used herein “single dose” refers to a dosage regiment consisting of one dose. Alternatively, a multi- dose regiment may be used. Without being bound by theory, the advantages of the specific binding molecule, recombinant fusion protein, recombinant fusion protein dimer or chimeric antigen receptor of the first, second, third, fourth, fifth, sixth aspects or pharmaceutical composition of the eighth aspect may be particularly apparent when administered in a single dose. Furthermore, in accordance with the present invention there is provided a method of treatment of a disease in a patient in need of treatment comprising administration to said patient of a therapeutically effective dosage of a bi-specific antigen binding molecule, recombinant fusion protein, recombinant fusion protein dimer or chimeric antigen receptor of the first, second, third, fourth, fifth or sixth aspects or a pharmaceutical composition of the eighth aspect, or the PTK7 specific binding molecule of the first configuration, or the recombinant fusion protein dimer of the second or third configuration. Preferably, the cancer is a ROR1-positive cancer type and/or a PTK7-positive cancer type. More preferably, the cancer is selected from the group comprising blood cancers such as lymphomas and leukemias, chronic lymphocytic leukaemia (CLL), mantle cell lymphoma (MCL), B-cell acute lymphoblastic leukaemia (B-ALL), marginal zone lymphoma (MZL), non-Hodgkin lymphomas (NHL), acute myeloid leukemia (AML) and solid tumours including neuroblastoma, renal cancer, lung cancer, colon cancer, ovarian cancer, pancreatic cancer, breast cancer, skin cancer, uterine cancer, prostate cancer, thyroid cancer, Head and Neck cancer, bladder cancer, oesophageal cancer, stomach cancer or liver cancer. Also provided herein is a method of assaying for the presence of a target analyte in a sample, comprising the addition of a detectably labelled bi-specific antigen binding molecule of the first aspect or second aspect, or a recombinant fusion protein of the third aspect, or a recombinant fusion protein dimer of the fourth or fifth aspect, or the PTK7 specific binding molecule of the first configuration, or the recombinant fusion protein dimer of the second or third configuration, to the sample and detecting the binding of the molecule to the target analyte. In addition, there is provided herein a method of imaging a site of disease in a subject, comprising administration of a detectably labelled bi-specific antigen binding molecule of the first aspect or second aspect, or a detectably labelled recombinant fusion protein of the third aspect, or a recombinant fusion protein dimer of the fourth or fifth aspect to a subject or the PTK7 specific binding molecule of the first configuration, or the recombinant fusion protein dimer of the second or third configuration. There is also provided herein a method of diagnosis of a disease or medical condition in a subject comprising administration of a bi-specific antigen binding molecule of the first aspect or second aspect, or a recombinant fusion protein of the third aspect, or a recombinant fusion protein dimer of the fourth or fifth aspect, or the PTK7 specific binding molecule of the first configuration, or the recombinant fusion protein dimer of the second or third configuration. Also contemplated herein is a bi-specific antigen binding molecule comprising an antibody, antibody fragment or antigen-binding molecule that competes for binding to ROR1 with the ROR1-specific antigen binding molecule of the first or second aspect. The term "compete" when used in the context of antigen binding proteins (e.g., neutralizing antigen binding proteins or neutralizing antibodies) means competition between antigen binding proteins as determined by an assay in which the antigen binding protein (e.g., antibody or functional fragment thereof) under test prevents or inhibits specific binding of a the antigen binding molecule defined herein (e.g., specific antigen binding molecule of the first aspect) to a common antigen (e.g., ROR1 in the case of the specific antigen binding molecule of the first or second aspect). Also described herein is a kit for diagnosing a subject suffering from cancer, or a pre-disposition thereto, or for providing a prognosis of the subject's condition, the kit comprising detection means for detecting the concentration of antigen present in a sample from a test subject, wherein the detection means comprises a bi-specific antigen binding molecule of the first or second aspect, a recombinant fusion protein of the third aspect, or a recombinant fusion protein dimer of the fourth or fifth aspect, a chimeric antigen receptor of the sixth aspect or a nucleic acid sequence of the seventh aspect, or the PTK7 specific binding molecule of the first configuration, or the recombinant fusion protein dimer of the second or third configuration, each being optionally derivatized, wherein presence of antigen in the sample suggests that the subject suffers from cancer. Preferably the antigen comprises ROR1 protein, more preferably an extracellular domain thereof. More preferably, the kit is used to identify the presence or absence of ROR1-positive cells in the sample, or determine the concentration thereof in the sample. The kit may also comprise a positive control and/or a negative control against which the assay is compared and/or a label which may be detected. The present invention also provides a method for diagnosing a subject suffering from cancer, or a pre- disposition thereto, or for providing a prognosis of the subject's condition, the method comprising detecting the concentration of antigen present in a sample obtained from a subject, wherein the detection is achieved using a bi-specific antigen binding molecule of the first or second aspect, a recombinant fusion protein of the third aspect, or a recombinant fusion protein dimer of the fourth or fifth aspect, a chimeric antigen receptor of the sixth aspect or a nucleic acid sequence of the seventh aspect, or the PTK7 specific binding molecule of the first configuration, or the recombinant fusion protein dimer of the second or third configuration each being optionally derivatized, and wherein presence of antigen in the sample suggests that the subject suffers from cancer. Also contemplated herein is a method of killing or inhibiting the growth of a cell expressing ROR1 and/or PTK7 in vitro or in a patient, which method comprises administering to the cell a pharmaceutically effective amount or dose of (i) bi-specific antigen binding molecule of the first or second aspect, a recombinant fusion protein of the third aspect, or a recombinant fusion protein dimer of the fourth or fifth aspect, a nucleic acid sequence of the seventh aspect, or the CAR or cell according to the sixth aspect, or (ii) of a pharmaceutical composition of the eighth aspect, or (iii) the PTK7 specific binding molecule of the first configuration, or the recombinant fusion protein dimer of the second or third configuration. Preferably, the cell expressing ROR1 and/or is a cancer cell. More preferably, the ROR1 is human ROR1 and/or the PTK7 is human PTK7. According to a ninth aspect, the invention provides a bi-specific antigen binding molecule comprising an amino acid sequence represented by the formula (II): X-FW1-CDR1-FW2-HV2-FW3a-HV4-FW3b-CDR3-FW4-Y (II) wherein FW1-CDR1-FW2-HV2-FW3a-HV4-FW3b-CDR3-FW4 is a ROR1-specific antigen binding molecule according to the first or second aspect X and Y are optional amino acid sequences wherein the ROR1-specific antigen binding molecule is conjugated to a second moiety and wherein the bi-specific antigen binding molecule further comprises a PTK7-specific antigen binding molecule. According to a tenth aspect, the invention provides a target-binding molecule-drug conjugate, comprising (a) a PTK7-specific binding molecule of the first configuration of the invention, or a bi-specific antigen binding molecule according to the first, second or ninth aspect, or a recombinant fusion protein of the third aspect or a recombinant fusion protein dimer of the fourth or fifth aspect or the second or third configuration, and (b) at least one toxin. DESCRIPTION OF FIGURES Figure 1: Design of B1 loop library: The sequence of B1 is shown with the “X” indicating amino acids within CDR1 and CDR3 which were randomised. Figure 2: Cell surface binding of B1 VNAR loop variants (His ₆ Myc tag) to A549 (ROR1 ^hi ) lung cancer cells by flow cytometry. Figure 3: Cell surface binding of B1 VNAR loop variants (His6Myc tag) to A427 (ROR1 ^low ) lung cancer cells by flow cytometry. Figure 4: Sequence and loop library design of P3A1 G1. CDR1 diversity results in 448 combinations, HV2 diversity results in 768 combinations and HV4 diversity results in 24 combinations. Figure 5: Binding of P3A1G1 loop variants to human ROR1 by ELISA. The data is plotted as the OD signal obtained at 450 nm for a fixed concentration (5 ug /mL) of each of the loop variants. Figure 6: Binding of P3A1G1 loop variants and parental P3A1G1 protein to human ROR1 by ELISA. Figure 7: Linker mouse IgG and linker human IgG sequences used in VNAR IgG Fc fusion proteins. Engineered hIgG1 Fc fusion proteins incorporate an engineered cysteine substitution in the hIgG1 Fc sequence, for example at position S239C or S442C (EU numbering) to enable site specific labelling. Figure 8: Cell surface binding of B1 loop variant – hFc fusion proteins to A549 (ROR1 ^hi ) lung cancer cells by flow cytometry. Figure 9: Analysis of ROR1 bi-paratopic VNAR-hFc fusions by SDS-PAGE (4-12% Bis Tris gel, MOPS buffer, ±50mM DTT). Lane 1 G3CP-P3A1 hFc (S239C+KIH) and lane 2 G3CPG4-P3A1 hFc (S239C+KIH) Figure 10: Cell surface binding of ROR1 bi-paratopic VNAR-hFc fusions to A549 (ROR1 ^hi ) and A427 (ROR1 ^low ) lung cancer cells by flow cytometry. Figure 11: Structures of PNU-linker payloads MA-PEG-vc-PAB-EDA-PNU159682 and MA- PEG-va-EDA-PNU159682 Figure 12: Dose response showing binding of G3CP-hFc and G3CPG4-hFc PNU conjugates and the corresponding parental proteins to human ROR1 by ELISA Figure 13: Potency of G3CP-hFc PNU and G3CPG4-hFc PNU conjugates in killing the ROR1 positive PA-1 cell-line and a PA-1 cell-line with ROR1 knockout Figure 14: In vivo efficacy of G3CP-hFc PNU and G3CPG4-hFc PNU conjugates in the ROR1+ HBCx-28 patient-derived TNBC xenograft model. Data plotted until the point when the first animal in the vehicle group reached humane tumour burden. Figure 15: An alignment of the sequences for B1, B1 G4, B1V15, G3CP and G3CPG4. Points of variation within the CDRs and HV regions are emphasised in underline. Note B1V15 (SEQ ID NO: 115): is not a loop library variant of B1; they have identical CDR1, HV2, HV4 and CDR3 sequences. Figure 16: UV analysis of B1-hFc, B1G4-hFc, G3CP-hFc and G3CPG4-hFc after incubation in PBS pH 7.4 buffer at 37°C for 96h. Figure 17: Size exclusion analysis (SEC) of B1-hFc, B1G4-hFc, G3CP-hFc and G3CPG4-hFc after incubation in PBS pH 7.4 buffer at 37°C for 96h. Figure 18: Potency of G3CP-hFc PNU and G3CPG4-hFc PNU conjugates in killing ROR1 ^low HEK293 cells and HEK293 cells stably transfected with human ROR1 Figure 19: In vivo efficacy of G3CP-hFc PNU and G3CPG4-hFc PNU conjugates in the ROR1+ HBCx-10 patient-derived TNBC xenograft model. Data plotted until the point when the first animal in the vehicle group reached humane tumour burden Figure 20: Cell surface binding of ROR1 mono– and bi-paratopic VNAR-hFc drug conjugates to A549 (ROR1 ^hi ) and A427 (ROR1 ^low ) lung cancer cells by flow cytometry. Figure 21: Potency of bi-paratopic G3CP-P3A1-hFc PNU and G3CPG4-P3A1-hFc PNU conjugates in killing the ROR1 positive PA-1 cell-line and a PA-1 cell-line with ROR1 knockout Figure 22: In vivo efficacy of bi-paratopic G3CP-P3A1 hFc PNU and G3CPG4-P3A1-hFc PNU conjugates in the ROR1+ HBCx-28 patient-derived TNBC xenograft model. Figure 23: Binding of VNAR clones to huPTK7 (ECD)-Fc, huPTK7 (5-7)-Fc or HSA by ELISA. CCK4, hu24 and E06 are controls. CCK4 – anti huPTK7 polyclonal antibody, hu24 is anti PTK7 antibody and E06 is an albumin-binding VNAR. Figure 24: Binding of VNAR clones to huPTK7 (ECD)-Fc, huPTK7 (5-7)-Fc or cynoPTK7-Fc and mouse PTK7-Fc in ELISA. CCK4, hu24 and E06 are controls. CCK4 – anti huPTK7 polyclonal antibody binding to mouse, cyno and human PTK7 (ECD). hu24 is anti PTK7 antibody. E06 is an albumin-binding VNAR used as a negative control Figure 25: Cell surface binding of PTK7 mono- and bi-paratopic VNAR-hFc fusion molecules to NCI-H661 (PTK7 ^hi ) and AsPC1 (PTK7 ^low ) human cancer cells by flow cytometry Figure 26: Cell surface binding of PTK7 mono- and bi-paratopic VNAR-hFc fusion molecules to NCI-H661 (PTK7 ^hi ) and AsPC1 (PTK7 ^low ) human cancer cells by flow cytometry. Figure 27: Cell surface binding of PTK7 mono- and bi-paratopic VNAR-hFc-drug conjugate molecules to NCI-H661 (PTK7 ^hi ) and AsPC1 (PTK7 ^low ) human cancer cells by flow cytometry. Figure 28: Cell surface binding of PTK7 mono- and bi-paratopic VNAR-hFc-drug conjugate molecules to NCI-H661 (PTK7 ^hi ) and AsPC1 (PTK7 ^low ) human cancer cells by flow cytometry. Figure 29: Cell surface binding of PTK7 mono- and bi-paratopic VNAR-hFc-drug conjugate molecules to NCI-H661 (PTK7 ^hi ) and AsPC1 (PTK7 ^low ) human cancer cells by flow cytometry. Figure 30: Potency of PTK7 mono- and bi-paratopic drug-conjugates in killing the PTK7 positive PA-1 cell-line and a PA-1 cell-line with PTK7 knockout Figure 31: In vivo efficacy of PTK7 mono- and bi-paratopic drug conjugates in the OVXF_OV55 patient-derived ovarian xenograft model. Figure 32: Binding of ROR1 x PTK7 hFc bi-specific proteins to ROR1 by ELISA. Binding to G3CP-P2A7 hFc, G3CPG4-P2A7 hFc, P3A1-P2A7 hFc and B1-P2A7 hFc (left) and binding to G3CP-4D2 hFc, G3CPG4-4D2 hFc, P3A1-4D2 hFc and B1-4D2 hFc (right) Figure 33: Binding of ROR1 x PTK7 hFc bi-specific proteins to PTK7 by ELISA. Binding to G3CP-P2A7 hFc, G3CPG4-P2A7 hFc, P3A1-P2A7 hFc and B1-P2A7 hFc (left) and binding to G3CP-4D2 hFc, G3CPG4-4D2 hFc, P3A1-4D2 hFc and B1-4D2 hFc (right) Figure 34: Size exclusion analysis (SEC) of G3CP-P2A7 hFc, G3CPG4-P2A7 hFc, P3A1-P2A7 hFc and B1-P2A7 hFc (top panel G ₄ S linker, bottom panel (G ₄ S) ₃ linker) before and after incubation in PBS pH 7.4 buffer at 37°C for 96h Figure 35: Size exclusion analysis (SEC) of G3CP-4D2 hFc, G3CPG4-4D2 hFc, P3A1-4D2 hFc and B1-4D2 hFc (top panel G ₄ S linker, bottom panel (G ₄ S) ₃ linker) before and after incubation in PBS pH 7.4 buffer at 37°C for 96h Figure 36: Potency of ROR1 x PTK7 bispecific drug-conjugates in killing the PTK7 positive PA- 1 cells, NCI-H1703 and normal human epidermal keratinocytes (NHEKAd). Figure 37: Western Blot analysis of PDX models from different cancer indications for dual ROR1 and PTK7 expression Figure 38: Further Western Blot analysis of PDX models from different cancer indications for dual ROR1 and PTK7 expression Figure 39: Cell surface binding of ROR1 x PTK7 VNAR hFc MMAE conjugate with corresponding ROR1 and PTK7 VNAR-hFc monospecific MMAE control conjugates to PA-1 (ROR1 ^hi / PTK7 ^hi ) and SW403 (ROR1 ^neg / PTK7 ^low ) human cancer cells by flow cytometry. Figure 40: Cell surface binding of ROR1 x PTK7 VNAR hFc MMAE conjugate with corresponding ROR1 and PTK7 VNAR-hFc monospecific MMAE control conjugates to PA-1 (ROR1 ^hi / PTK7 ^hi ) and SW403 (ROR1 ^neg / PTK7 ^low ) human cancer cells by flow cytometry. Figure 41: Internalisation of ROR1 x PTK7 VNAR hFc MMAE conjugate with corresponding ROR1 and PTK7 VNAR-hFc monospecific MMAE control conjugates to HEK-293-ROR1 (ROR1 ^hi / PTK7 ^hi ). Figure 42: Potency of ROR1 x PTK7 bispecific drug-conjugates in killing the ROR1 positive and PTK7 positive NCI-H1975 cells lung adenocarcinoma cells. Figure 43: Cell surface binding of ROR1 x PTK7 VNAR hFc PNU conjugate with corresponding ROR1 and PTK7 VNAR-hFc monospecific PNU control conjugates to PA-1 (ROR1 ^hi / PTK7 ^hi ) and SW403 (ROR1 ^neg / PTK7 ^low ) human cancer cells by flow cytometry. Figure 44: Cell surface binding of ROR1 x PTK7 VNAR hFc PNU conjugate with corresponding ROR1 and PTK7 VNAR-hFc monospecific PNU control conjugates to PA-1 (ROR1 ^hi / PTK7 ^hi ) and SW403 (ROR1 ^neg / PTK7 ^low ) human cancer cells by flow cytometry. Figure 45: Potency of ROR1 x PTK7 bispecific PNU drug-conjugates in killing the PTK7 positive PA-1 cells, and normal human epidermal keratinocytes (NHEKAd). DETAILED DESCRIPTION The present invention generally relates to bi-specific antigen binding molecules. Specifically, the invention provides immunoglobulin-like shark variable novel antigen receptors (VNARs) specific for receptor tyrosine kinase-like orphan receptor 1 (ROR1) and associated fusion proteins, chimeric antigen receptors, conjugates, and nucleic acids, as well as accompanying methods. The ROR1-specifc VNAR domains are described herein as ROR1-specific antigen binding molecules. The Novel or New antigen receptor (IgNAR) is an approximately 160 kDa homodimeric protein found in the sera of cartilaginous fish (Greenberg A. S., et al., Nature, 1995.374(6518): p.168-173, Dooley, H., et al, Mol. Immunol, 2003. 40(1): p.25-33; Müller, M.R., et al., mAbs, 2012.4(6): p. 673-685)). Each molecule consists of a single N-terminal variable domain (VNAR) and five constant domains (CNAR). The IgNAR domains are members of the immunoglobulin-superfamily. The VNAR is a tightly folded domain with structural and some sequence similarities to the immunoglobulin and T-cell receptor Variable domains and to cell adhesion molecules and is termed the VNAR by analogy to the N Variable terminal domain of the classical immunoglobulins and T Cell receptors. The VNAR shares limited sequence homology to immunoglobulins, for example 25-30% similarity between VNAR and human light chain sequences. Kovaleva M. et al Expert Opin. Biol. Ther.2014.14(10): p.1527-1539 and Zielonka S. et al mAbs 2015. 7(1): p.15-25 provided summaries of the structural characterization and generation of the VNARs, which are hereby incorporated by reference. The VNAR does not appear to have evolved from a classical immunoglobulin antibody ancestor. The distinct structural features of VNARs are the truncation of the sequences equivalent to the CDR2 loop present in conventional immunoglobulin variable domains and the lack of the hydrophobic VH/VL interface residues which would normally allow association with a light chain domain, which is not present in the IgNAR structure. Furthermore, unlike classical immunoglobulins some VNAR subtypes include extra cysteine residues in the CDR regions that are observed to form disulphide bridges in addition to the canonical Immunoglobulin superfamily bridge between the Cysteines in the Framework 1 and 3 regions N terminally adjacent to CDRs 1 and 3. To date, there are three defined types of shark IgNAR known as I, II and III. These have been categorized based on the position of non-canonical cysteine residues which are under strong selective pressure and are therefore rarely replaced. All three types have the classical immunoglobulin canonical cysteines at positions 35 and 107 (numbering as in Kabat, E.A. et al. Sequences of proteins of immunological interest. 5th ed. 1991, Bethesda: US Dept. of Health and Human Services, PHS, NIH) that stabilize the standard immunoglobulin fold, together with an invariant tryptophan at position 36. There is no defined CDR2 as such, but regions of sequence variation that compare more closely to TCR HV2 and HV4 have been defined in framework 2 and 3 respectively. Type I has germline encoded cysteine residues in framework 2 and framework 4 and an even number of additional cysteines within CDR3. Crystal structure studies of a Type I IgNAR isolated against and in complex with lysozyme enabled the contribution of these cysteine residues to be determined. Both the framework 2 and 4 cysteines form disulphide bridges with those in CDR3 forming a tightly packed structure within which the CDR3 loop is held tightly down towards the HV2 region. To date Type I IgNARs have only been identified in nurse sharks - all other elasmobranchs, including members of the same order have only Type II or variations of this type. Type II IgNAR are defined as having a cysteine residue in CDR1 and CDR3 which form intramolecular disulphide bonds that hold these two regions in close proximity, resulting in a protruding CDR3 that is conducive to binding pockets or grooves. Type I sequences typically have longer CDR3s than type II with an average of 21 and 15 residues respectively. This is believed to be due to a strong selective pressure for two or more cysteine residues in Type I CDR3 to associate with their framework 2 and 4 counterparts. Studies into the accumulation of somatic mutations show that there are a greater number of mutations in CDR1 of type II than type I, whereas HV2 regions of Type I show greater sequence variation than Type II. This evidence correlates well with the determined positioning of these regions within the antigen binding sites. A third IgNAR type known as Type III has been identified in neonates. This member of the IgNAR family lacks diversity within CDR3 due to the germline fusion of the D1 and D2 regions (which form CDR3) with the V-gene. Almost all known clones have a CDR3 length of 15 residues with little or no sequence diversity. Another structural type of VNAR, termed type (IIb or IV), has only two canonical cysteine residues (in framework 1 and framework 3b regions). So far, this type has been found primarily in dogfish sharks and was also isolated from semisynthetic V-NAR libraries derived from wobbegong sharks. The VNAR binding surface, unlike the variable domains in other natural immunoglobulins, derives from four regions of diversity: CDR1, HV2, HV4 and CDR3, joined by intervening framework sequences in the order: FW1-CDR1-FW2-HV2-FW3a-HV4-FW3b-CDR3-FW4. The combination of a lack of a natural light chain partner and lack of CDR2 make VNARs the smallest naturally occurring binding domains in the vertebrate kingdom. The IgNAR shares some incidental features with the heavy chain only immunoglobulin (HCAb) found in camelidae (camels, dromedaries and llamas) Unlike the IgNAR the HCAb is clearly derived from the immunoglobulin family and shares significant sequence homology to standard immunogloblulins. Importantly one key distinction of VNARs is that the molecule has not had at any point in its evolution a partner light chain, unlike classical immunoglobulins or the HCAbs. Flajnik M.F. et al PLoS Biol 2011. 9(8): e1001120 and Zielonka S. et al mAbs 2015.7(1): p.15-25 have commented on the similarities and differences between, and the possible and distinct evolutionary origins of, the VNAR and the immunoglobulin-derived VHH single binding domain from the camelids. Although antibodies to ROR1 have been reported in the literature, the high sequence identity between the extracellular domain of human, mouse and rat ROR1 and between human ROR1 and ROR2 family members means generating high affinity hROR1-specifc binding agents is not trivial. Additionally, the large size of antibodies compromises their ability to penetrate into solid tumours and render regions of target proteins inaccessible due to steric factors, which can be particularly acute for cell-surface proteins where oligomerisation or receptor clustering is observed. As a result there is a need in the art for improved anti-ROR1 binding protein agents with different functional or physical characteristics or properties to antibodies and the development of therapeutics and diagnostic agents for malignancies associated with ROR1 expression. The present invention provides such agents in the form of the ROR1-specific antigen binding molecules described herein. Without being bound by theory, the presently-described ROR1-specific antigen binding molecules are thought to bind to both human and murine ROR1. A number of variants, including G3CP, G3CPG4, 1E5, 1B11, C3CP, 1G9, 1H8, G11CP, D9CP, 1B6, 1 F10, F2CP, B6CP, 1E1 and P3A1, P3A1G1 NAC6.S, P3A1G1 AE3.S, P3A1G1 NAC6, P3A1G1 AE3 and P3A1G1 NAG8 have been experimentally confirmed to bind to both hROR1 and mROR1. Furthermore, the ROR1-specific antigen binding molecules described herein may bind to deglycosylated forms of ROR1. Furthermore, they may not bind to a number of linear peptides associated with anti-ROR1 antibodies described in the prior art. The presently- described ROR1-specific antigen binding molecules are therefore thought to bind to distinct epitopes in the ROR1 sequence compared to these prior art anti-ROR1 antibodies. Binding of ROR1-specific antigen binding molecules to cancer cell lines, as well as internalisation, have been demonstrated. This confirms the potential for the use of such molecules in the treatment of cancers, specifically cancers which express ROR1. Various forms of the ROR1-specific antigen binding molecules are described, including fusion proteins of several types. Fusion proteins including an immunoglobulin Fc region are described, as well as both homo and heterodimers. Fusion of proteins to an Fc domain can improve protein solubility and stability, markedly increase plasma half-life and improve overall therapeutic effectiveness. The present inventors have also created VNAR molecules conjugated to a variety of moieties and payloads. The application therefore discloses chemically conjugated VNARs. More specifically, ROR1- specific antigen binding molecules in several conjugated formats are provided. ROR1-specific antigen binding molecules described herein have been formatted in combination with an PTK7-specific binding molecule. The present invention therefore relates to bi-specific ROR1/PTK7 antigen binding molecules. In a first configuration, the invention provides a PTK7-specific binding molecule as disclosed as part of any of the following aspects of the invention. The invention therefore provides a mono-specific PTK7 binding molecule. The mono-specific PTK7 binding molecule may comprise the amino acid sequence of any PTK7 specific binding molecule disclosed herein, including those disclosed in the context of bi- specific antigen binding molecules. The mono-specific PTK7 binding molecule may comprise any CDR1 and/or CDR3 sequence of any PTK7 specific binding molecule disclosed herein, including those disclosed in the context of bi-specific antigen binding molecules. The mono-specific PTK7 binding molecule may comprise any HV2 and/or HV4 sequence of any PTK7 specific binding molecule disclosed herein, including those disclosed in the context of bi-specific antigen binding molecules. The mono-specific PTK7 binding molecule may comprise any FW1, FW2, FW3a, FW3b and/or FW4 sequence of any PTK7 specific binding molecule disclosed herein, including those disclosed in the context of bi-specific antigen binding molecules. The mono-specific PTK7 binding molecule may have the characteristics of any PTK7 specific binding molecule disclosed herein, including those disclosed in the context of bi-specific antigen binding molecules. According to a first aspect, the invention provides a bi-specific antigen binding molecule comprising: (i) a receptor tyrosine kinase-like orphan receptor 1 (ROR1) specific antigen binding molecule comprising an amino acid sequence represented by the formula (I): FW1-CDR1-FW2-HV2-FW3a-HV4-FW3b-CDR3-FW4 (I) wherein CDR3 is a CDR sequence having an amino acid sequence selected from the group consisting of YPWGAGAPYNVQWY (SEQ ID NO: 23), YPWGAGAPYLVQWY (SEQ ID NO: 20), YPWGAGAPWNVQWY (SEQ ID NO: 24), YPSGAGAPRPVQWY (SEQ ID NO: 11), YPWGAGAPCLVQWY (SEQ ID NO: 12), YPWGAGAPRLVQWY (SEQ ID NO: 13), YPWGAGAPRQVQWY (SEQ ID NO: 14), YPWGAGAPRSVQWY (SEQ ID NO: 15), YPWGAGAPSLVQWY (SEQ ID NO: 16), YPWGAGAPSNVQWY (SEQ ID NO: 17), YPWGAGAPSQVQWY (SEQ ID NO: 18), YPWGAGAPSSVQWY (SEQ ID NO: 19), YPWGAGAPWQVQWY (SEQ ID NO: 21), YPWGAGAPWSVQWY (SEQ ID NO: 22), and YPWGAGAPWLVQWY (SEQ ID NO: 10); CDR1 is a CDR sequence having an amino acid sequence selected from the group consisting of GANYGLAA (SEQ ID NO: 1), DANYGLAA (SEQ ID NO: 5), GANYDLSA (SEQ ID NO: 2), GANYGLSA (SEQ ID NO: 3), and GANYDLAA (SEQ ID NO: 4) FW1 is a framework region; FW2 is a framework region; HV2 is a hypervariable sequence having an amino acid sequence selected from the group consisting of SSNQERISIS (SEQ ID NO: 6), and SSNKERISIS (SEQ ID NO: 7); FW3a is a framework region; HV4 is a hypervariable sequence having an amino acid sequence selected from the group consisting of NKRTM (SEQ ID NO: 8) and NKGTM (SEQ ID NO: 9); FW3b is a framework region; FW4 is a framework region; wherein if CDR3 is YPWGAGAPWLVQWY (SEQ ID NO: 10) then CDR1 is selected from the group consisting of DANYGLAA (SEQ ID NO: 5), GANYGLSA (SEQ ID NO: 3) and GANYDLAA (SEQ ID NO: 4); and (ii) a protein tyrosine kinase 7 (PTK7) specific antigen binding molecule. In one embodiment of the ROR1-specific antigen binding molecule: CDR3 is a CDR sequence having an amino acid sequence selected from the group consisting of YPWGAGAPYNVQWY (SEQ ID NO: 23), YPWGAGAPYLVQWY (SEQ ID NO: 20), YPWGAGAPWNVQWY (SEQ ID NO: 24), YPSGAGAPRPVQWY (SEQ ID NO:11), YPWGAGAPCLVQWY (SEQ ID NO: 12), YPWGAGAPRLVQWY (SEQ ID NO:13), YPWGAGAPRQVQWY (SEQ ID NO: 14), YPWGAGAPRSVQWY (SEQ ID NO: 15), YPWGAGAPSLVQWY (SEQ ID NO: 16), YPWGAGAPSNVQWY (SEQ ID NO: 17), YPWGAGAPSSVQWY (SEQ ID NO: 19), YPWGAGAPWQVQWY (SEQ ID NO: 21), YPWGAGAPWSVQWY (SEQ ID NO: 22), and YPWGAGAPWLVQWY (SEQ ID NO: 10). If CDR3 is not YPWGAGAPWLVQWY (SEQ ID NO: 10) then CDR1 may be a CDR sequence having an amino acid sequence selected from the group consisting of GANYGLAA (SEQ ID NO: 1), DANYGLAA (SEQ ID NO: 5), GANYDLSA (SEQ ID NO: 2), GANYGLSA (SEQ ID NO: 3), and GANYDLAA (SEQ ID NO: 4). Accordingly, the ROR1 specific antigen binding molecule may be defined as comprising an amino acid sequence represented by the formula (I): FW1-CDR1-FW2-HV2-FW3a-HV4-FW3b-CDR3-FW4 (I) wherein CDR3 is a CDR sequence having an amino acid sequence selected from the group consisting of YPWGAGAPYNVQWY (SEQ ID NO: 23), YPWGAGAPYLVQWY (SEQ ID NO: 20), YPWGAGAPWNVQWY (SEQ ID NO: 24), YPSGAGAPRPVQWY (SEQ ID NO:11), YPWGAGAPCLVQWY (SEQ ID NO: 12), YPWGAGAPRLVQWY (SEQ ID NO:13), YPWGAGAPRQVQWY (SEQ ID NO: 14), YPWGAGAPRSVQWY (SEQ ID NO: 15), YPWGAGAPSLVQWY (SEQ ID NO: 16), YPWGAGAPSNVQWY (SEQ ID NO: 17), YPWGAGAPSQVQWY (SEQ ID NO: 18), YPWGAGAPSSVQWY (SEQ ID NO: 19), YPWGAGAPWQVQWY (SEQ ID NO: 21), and YPWGAGAPWSVQWY (SEQ ID NO: 22); CDR1 is a CDR sequence having an amino acid sequence selected from the group consisting of GANYGLAA (SEQ ID NO: 1), DANYGLAA (SEQ ID NO: 5), GANYDLSA (SEQ ID NO: 2), GANYGLSA (SEQ ID NO: 3), and GANYDLAA (SEQ ID NO: 4); FW1 is a framework region; FW2 is a framework region; HV2 is a hypervariable sequence having an amino acid sequence selected from the group consisting of SSNQERISIS (SEQ ID NO: 6) and SSNKERISIS (SEQ ID NO: 7); FW3a is a framework region; HV4 is a hypervariable sequence having an amino acid sequence selected from the group consisting of NKRTM (SEQ ID NO: 8) and NKGTM (SEQ ID NO: 9); FW3b is a framework region; and FW4 is a framework region. In one embodiment of the ROR1-specific antigen binding molecule: CDR3 is a CDR sequence having an amino acid sequence selected from the group consisting of YPWGAGAPYNVQWY (SEQ ID NO: 23), YPWGAGAPYLVQWY (SEQ ID NO: 20) and YPWGAGAPWNVQWY (SEQ ID NO: 24), and/or CDR1 is a CDR sequence having an amino acid sequence selected from the group consisting of GANYGLAA (SEQ ID NO: 1) and DANYGLAA (SEQ ID NO: 5). In one embodiment of the ROR1-specific antigen binding molecule: CDR3 is a CDR sequence having an amino acid sequence according to YPWGAGAPYNVQWY (SEQ ID NO: 23). In one embodiment of the ROR1-specific antigen binding molecule: CDR3 is a CDR sequence having an amino acid sequence according to YPWGAGAPYNVQWY (SEQ ID NO: 23); CDR1 is a CDR sequence having an amino acid sequence according to GANYGLAA (SEQ ID NO: 1); HV2 is a hypervariable sequence having an amino acid sequence according to SSNQERISIS (SEQ ID NO: 6); and HV4 is a hypervariable sequence having an amino acid sequence according to NKRTM (SEQ ID NO: 8). In one embodiment of the ROR1-specific antigen binding molecule: CDR3 is a CDR sequence having an amino acid sequence according to YPWGAGAPYNVQWY (SEQ ID NO: 23); CDR1 is a CDR sequence having an amino acid sequence according to DANYGLAA (SEQ ID NO: 5); HV2 is a hypervariable sequence having an amino acid sequence according to SSNKERISIS (SEQ ID NO: 7); and HV4 is a hypervariable sequence having an amino acid sequence according to NKGTM (SEQ ID NO: 9). In one embodiment of the ROR1-specific antigen binding molecule: CDR3 is a CDR sequence having an amino acid sequence according to YPWGAGAPWLVQWY (SEQ ID NO: 10); CDR1 is a CDR sequence having an amino acid sequence according to DANYGLAA (SEQ ID NO: 5); HV2 is a hypervariable sequence having an amino acid sequence according to SSNKERISIS (SEQ ID NO: 7); and HV4 is a hypervariable sequence having an amino acid sequence according to NKGTM (SEQ ID NO: 9). In preferred embodiments the ROR1-specific antigen binding molecule comprises an amino acid sequence selected from the group consisting of: ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVN (SEQ ID NO: 50) referred to herein as G3CP; TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPWLVQWY DGAGTKVEIK (SEQ ID NO: 51) referred to herein as B1G4; ASVNQTPRTATKETGESLTINCVVTGANYDLSATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPSGAGAPRPVQWYDGAGTVLTVN (SEQ ID NO: 52) referred to herein as 1E2; ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPCLVQWYDGAGTVLTVN (SEQ ID NO: 53) referred to herein as 1E5; ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPRLVQWYDGAGTVLTVN (SEQ ID NO: 54) referred to herein as 1B11; ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPRQVQWYDGAGTVLTVN (SEQ ID NO: 55) referred to herein as C3CP; ASVNQTPRTATKETGESLTINCVVTGANYGLSATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPRSVQWYDGAGTVLTVN (SEQ ID NO: 56) referred to herein as 2G5; ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPRSVQWYDGAGTVLTVN (SEQ ID NO: 57) referred to herein as 1G12; ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSLVQWYDGAGTVLTVN (SEQ ID NO: 58) referred to herein as G5CP; ASVNQTPRTATKETGESLTINCVVTGANYGLSATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSNVQWYDGAGTVLTVN (SEQ ID NO: 59) referred to herein as 2F4; ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSQVQWYDGAGTVLTVN (SEQ ID NO: 60) referred to herein as 1G9; ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSSVQWYDGAGTVLTVN (SEQ ID NO: 61) referred to herein as 1H8; ASVNQTPRTATKETGESLTINCVVTGANYGLSATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPWLVQWYDGAGTVLTVN (SEQ ID NO: 62) referred to herein as G11CP; ASVNQTPRTATKETGESLTINCVVTGANYDLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPWLVQWYDGAGTVLTVN (SEQ ID NO: 63) referred to herein as D9CP; ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPWNVQWYDGAGTVLTVN (SEQ ID NO: 64) referred to herein as 1B6; ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPWQVQWYDGAGTVLTVN (SEQ ID NO: 65) referred to herein as 1F10; ASVNQTPRTATKETGESLTINCVVTGANYGLSATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPWQVQWYDGAGTVLTVN (SEQ ID NO: 66) referred to herein as E6CP; ASVNQTPRTATKETGESLTINCVVTGANYDLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPWQVQWYDGAGTVLTVN (SEQ ID NO: 67) referred to herein as F2CP; ASVNQTPRTATKETGESLTINCVVTGANYDLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPWSVQWYDGAGTVLTVN (SEQ ID NO: 68) referred to herein as B6CP; ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPWSVQWYDGAGTVLTVN (SEQ ID NO: 69) referred to herein as 1G1; and ASVNQTPRTATKETGESLTINCVVTGANYGLSATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPWSVQWYDGAGTVLTVN (SEQ ID NO: 70) referred to herein as A10CP; or a functional variant having CDR1, HV2, HV4 and CDR2 sequences according to any thereof and having FW1, FW2, FW3a, FW3b and FW4 sequences having a combined sequence identity of at least 45% to the combined FW1, FW2, FW3a, FW3b and FW4 sequences of any thereof. In a particularly preferred embodiment, the ROR1-specific antigen binding molecule may comprise an amino acid sequence according to ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVN (SEQ ID NO: 50). The ROR1-specific antigen binding molecule may comprise an amino acid sequence according to ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVN (SEQ ID NO: 50) or a functional variant thereof having CDR1, HV2, HV4 and CDR2 sequences according to SEQ ID NO: 50 and having FW1, FW2, FW3a, FW3b and FW4 sequences having a combined sequence identity of at least 45% to the combined FW1, FW2, FW3a, FW3b and FW4 sequences of SEQ ID NO: 50. Particular advantages associated with SEQ ID NO: 50 (“G3CP”) and functional variants thereof include increased expression yields and hydrophilicity and increased ease of analysis, purification and monomericity in non-optimised aqueous buffer systems for these proteins. Without being bound by theory, these advantages may be particularly evident in VNAR-hFc fusion proteins comprising the G3CP sequence or functional variants thereof. The G3CP sequence and functional variants thereof may therefore provide improved manufacturing and/or handling properties. Furthermore, G3CP-hFc shows excellent in vivo efficacy in a patient-derived xenograft model of Triple Negative Breast Cancer (TNBC) when conjugated to a cytotoxic anthracycline (PNU) derivative. The effect of G3CP-hFc is surprisingly improved over even B1-hFc which itself shows excellent in vivo efficacy. Moreover, as shown herein, ROR1xPTK7 bi-specifics comprising G3CP have shorter retention time (RT) in size exclusion chromatography (SEC) compared to B1 comprising bi-specifics, indicating improved hydrophilicity of ROR1xPTK7 bi-specifics containing G3CP. Furthermore, ROR1xPTK7 bi- specifics comprising G3CP may have reduced turbidity and reduced formation of high molecular weight (HMW) species compared to B1 comprising bi-specifics, indicating increased ease of analysis, purification and monomericity of ROR1xPTK7 bi-specifics comprising G3CP in non-optimised aqueous buffer systems for these proteins. Therefore, the G3CP sequence and functional variants thereof may therefore provide improved manufacturing and/or handling properties that are retained in ROR1xPTK7 bi-specific format. Without being bound by theory, ROR1 x PTK7 bi-specifics, including but not limited to those comprising the G3CP sequence, may also improve efficacy where ROR1 mono-specifics are refractory or have low specificity. For instance, disclosed herein are data showing not only co-expression of ROR1 and PTK7 in TNBC (the application also contains data showing excellent in vivo efficacy of a G3CP-hFc PNU conjugate in a patient-derived xenograft model of TNBC) but high expression of PTK7 alongside ROR1 expression in non-small cell lung cancer models and ovarian cancer models using western blotting. Co- expression of ROR1 and PTK7 is also identified in models of triple negative breast cancer (TNBC), breast adenocarcinoma, sarcoma, lung adenocarcinoma, lung squamous cell carcinoma, large cell lung carcinoma, small cell lung carcinoma and pleural mesothelioma. The surprisingly improved effect of a G3CP-hFc PNU conjugate in a patient-derived xenograft model of TNBC compared to B1-hFc PNU, combined with the in vitro data disclosed herein, therefore indicate the therapeutic potential of the presently claimed ROR1 x PTK7 bi-specifics in the potential treatment of cancers co-expressing ROR1 and PTK7, such as those identified herein. In a particularly preferred embodiment, the ROR1-specific antigen binding molecule may comprise an amino acid sequence according to ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSSVQWYDGAGTVLTVN (SEQ ID NO: 61). Particular advantages associated with SEQ ID NO: 61 (“1H8”) and functional variants thereof include good stability in PBS, at least in a 1H8-Fc fusion and measured by SEC (t = 0 vs 96h), which is improved relative to B1-hFc under the same conditions. In a particularly preferred embodiment, the ROR1-specific antigen binding molecule may comprise an amino acid sequence according to TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPWLVQWYDGAGTKVEIK (SEQ ID NO: 51). Particular advantages associated with SEQ ID NO: 51 (“B1G4”) and functional variants thereof include increased expression yields and monomericity in aqueous buffer systems for fusion proteins comprising the B1G4 sequence or functional variants thereof, such as VNAR-hFc fusion proteins. The B1G4 sequence and functional variants thereof may therefore provide fusion proteins with improved manufacturing and/or handling properties. The ROR1-specific antigen binding molecule may comprise an amino acid sequence according to TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPWLVQWYDGAGTKVEIK (SEQ ID NO: 51) or a functional variant thereof having CDR1, HV2, HV4 and CDR2 sequences according to SEQ ID NO: 51 and having FW1, FW2, FW3a, FW3b and FW4 sequences having a combined sequence identity of at least 45% to the combined FW1, FW2, FW3a, FW3b and FW4 sequences of SEQ ID NO: 51. In preferred embodiments the ROR1-specific antigen binding molecule comprises an amino acid sequence selected from the group consisting of: TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIK (SEQ ID NO: 71) referred to herein as G3CP G4; ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPYNVQWYDGQGTKLEVK (SEQ ID NO: 72) referred to herein as G3CP V15; TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPSSVQWYDGAGTKVEIK (SEQ ID NO: 73) referred to herein as 1H8 G4; ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPSSVQWYDGQGTKLEVK (SEQ ID NO: 74) referred to herein as 1H8 V15; TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPRQVQWYDGAGTKVEIK (SEQ ID NO: 75) referred to herein as C3CP G4; and ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPRQVQWYDGQGTKLEVK (SEQ ID NO: 76) referred to herein as C3CPV15; or a functional variant having CDR1, HV2, HV4 and CDR2 sequences according to any thereof and having FW1, FW2, FW3a, FW3b and FW4 sequences having a combined sequence identity of at least 45% to the combined FW1, FW2, FW3a, FW3b and FW4 sequences of any thereof. In a particularly preferred embodiment, the ROR1-specific antigen binding molecule may comprise an amino acid sequence according to TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIK (SEQ ID NO: 71). The ROR1-specific antigen binding molecule may comprise an amino acid sequence according to TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIK (SEQ ID NO: 71) or a functional variant thereof having CDR1, HV2, HV4 and CDR2 sequences according to SEQ ID NO: 71 and having FW1, FW2, FW3a, FW3b and FW4 sequences having a combined sequence identity of at least 45% to the combined FW1, FW2, FW3a, FW3b and FW4 sequences of SEQ ID NO: 71. Particular advantages associated with SEQ ID NO: 71 (“G3CP G4”) and functional variants thereof include increased expression yields and hydrophilicity and increased ease of analysis, purification and monomericity in non-optimised aqueous buffer systems for these proteins. Without being bound by theory, these advantages may be particularly evident in VNAR-hFc fusion proteins comprising the G3CP G4 sequence or functional variants thereof. The G3CP G4 sequence and functional variants thereof may therefore provide improved manufacturing and/or handling properties. Furthermore, G3CPG4-hFc shows excellent in vivo efficacy in a patient-derived xenograft model of Triple Negative Breast Cancer (TNBC) when conjugated to a cytotoxic anthracycline (PNU) derivative. The effect of G3CPG4-hFc is surprisingly improved over even B1-hFc which itself shows excellent in vivo efficacy. Moreover, as shown herein, ROR1xPTK7 bi-specifics comprising G3CP G4 have shorter retention time (RT) in size exclusion chromatography (SEC) compared to B1 comprising bi-specifics, indicating improved hydrophilicity of ROR1xPTK7 bi-specifics containing G3CP G4. Without being bound by theory, ROR1 x PTK7 bi-specifics, including but not limited to those comprising the G3CP G4 sequence, may also improve efficacy where ROR1 mono-specifics are refractory or have low specificity. For instance, disclosed herein are data showing not only co-expression of ROR1 and PTK7 in TNBC (the application also contains data showing excellent in vivo efficacy of a G3CPG4-hFc PNU conjugate in a patient-derived xenograft model of TNBC) but high expression of PTK7 alongside ROR1 expression in non-small cell lung cancer models and ovarian cancer models using western blotting. The surprisingly improved effect of a G3CPG4-hFc PNU conjugate in a patient-derived xenograft model of TNBC compared to B1-hFc PNU, combined with the in vitro data disclosed herein, therefore indicate the therapeutic potential of the presently claimed ROR1 x PTK7 bi-specifics in the potential treatment of cancers identified herein as co-expressing ROR1 and PTK7. The sequences of G3CP and G3CPG4 have in common two single amino acid changes relative to the sequence of B1. These are both within CDR3 and are the substitution: 1. Of a W residue with a Y residue, and 2. Of an L residue with a N residue. Compared to G3CP, G3CPG4 has a further single amino acid change in each of CDR1, HV2 and HV4 relative to B1 (which also appear in B1 G4) and changes to humanise the framework regions (some of which also appear in B1V15, SEQ ID NO: 115, as shown in Figure 15 - B1V15 has the same CDR1, HV2, HV4 and CDR3 sequences as B1 i.e. it is not a loop library variant; the changes to B1V15 relative to B1 are in the framework regions only). Without being bound by theory, any improvements over B1 shown by both G3CP and G3CPG4 which are not shown by B1 G4 or B1 V15 are thought to result from one or both of the two mutations they share in CDR3. Accordingly, advantages of G3CP and G3CPG4 are thought to derive from a CDR3 comprising the sequence YPWGAGAPYNVQWY (SEQ ID NO: 23). Without being bound by theory, the surprising advantages associated with YPWGAGAPYNVQWY (SEQ ID NO: 23) may represent a synergistic effect of both the W to Y and the L to N substitutions. Alternatively, the surprising advantages may derive primarily from the W to Y substitution thus being shared by YPWGAGAPYLVQWY (SEQ ID NO: 20).1B6, which has the L to N mutation and a CDR3 sequence of YPWGAGAPWNVQWY (SEQ ID NO: 24), has a lower elution volume than B1, therefore the L to N mutation in CDR3 does lead to improved manufacturing and/or handling properties. The PTK7-specific antigen binding molecule may be any molecule which binds to PTK7. In particular, the PTK7-specific antigen binding molecule may be selected from the group comprising an immunoglobulin, an immunoglobulin Fab region, an Fv, a single chain Fv (scFv), a diabody, a triabody, a tetrabody, a VNAR domain, a single domain antibody (sdAb), a VH domain, or a scaffold protein (affibodies, centyrins, darpins etc.). Preferably, the PTK7-specific antigen binding molecule is a VNAR domain. Preferably, the PTK7 specific antigen binding molecule for use in the bi-specific antigen binding molecule of the first aspect of the invention is selected from the group comprising: P2A2: ASVNQTPRTATKETGESLTINCVLTDTDPWWVRTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSF SLRIKDLTVADSATYYCKAWWHIDWFTRMWYDGAGTVLTVN (SEQ ID NO: 439) P2A7: TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVN (SEQ ID NO: 440) P2B1: ASVDQTPRTATKETGESLTINCVLTDTWEEDMTTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSF SLRIKDLTVADSATYYCKAWWSPSYYSFMWYDGAGTVLTVN (SEQ ID NO: 441) P2B12: ASVNQTPRTATKETGESLTINCVLTDTDDQVPATSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAWWWDGNWVWVWYDGAGTVLTVN (SEQ ID NO: 442) P2C6: TRVDQTPRTATKETGESLTINCVLTDTDDGWPTTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSF SLRIKDLTVADSATYYCKAWWEWDLYTWYWYDGAGTVLTVN (SEQ ID NO: 443) P2C7: TRVDQTPRTATKETGESLTINCVLTDTEVWWPKTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSF SLRIKDLTVADSATYYCKAWWKWAEYVWYWYDGAGTVLTVN (SEQ ID NO: 444) P2F8: ASVNQTPRTATKETGESLTINCVLTDTTWTDELTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAWWQTSYLVWGWYDGAGTDLTVN (SEQ ID NO: 445) P2G3 TRVDQTPRTATKETGESLTINCVLTDTDDPVHTTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAWWEWDLFTWYWYDGAGTVLTVN (SEQ ID NO: 446) P2H9: ASVNQTPRTATKETGESLTINCVLTDTNHDLYTTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAAALNNGFLVWYDGAGTVLTVN (SEQ ID NO: 447) 4A12: TRVDQTPRTATKETGESLTINCVLTDTSCGLYNTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYICRATMELCQAERINGYDGAGTVLTVN (SEQ ID NO: 448) 4C7: ASVNQTPRTATKETGESLTINCVVTGARCGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSF SLRIKDLTVADSATYYCKA.TNCYYNHVDGAGTVLTVN (SEQ ID NO: 449) 4E5: ASVNQTPRTATKETGESLTINCVVTGASCSWSGTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSF SLRIKDLTVADSATYYCKAVTYCISTNDMDLEYVYGAGTVLTVN (SEQ ID NO: 450) 4H3: TRVDQTPRTATKETGESLTINCVVTGASCALYRTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKARACKYDRFHVDGAGTVLTVN (SEQ ID NO: 451) 4D2: ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVN (SEQ ID NO: 452) E02: ASVNQTPRTATKETGESLTINCVVTGAGYALAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAFLPPRVWHGVKMQHWYDGAGTVLTVN (SEQ ID NO: 453) PB4: ASVNQTPRTATKETGESLTINCVLTDTWEEDMTTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSF SLRIKDLTVADSATYYCKAWWSPSYYSFMWYDGAGTVLTVN (SEQ ID NO: 454) PC2: ASVNQTPRTATKETGESLTINCVLTDTWGPEVHTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSF SLRIKDLTVADSATYYCKAWWNADYYVFYWYDGAGTVLTVN (SEQ ID NO: 455) Cofetuxumab Pelidotin, consists of a humanised mouse anti-PTK7 monoclonal antibody (hu24) conjugated with an auristatin 0101 payload, via mc-valine-citrulline-PABC linker, using endogenous cysteine residues. The PTK7 specific antigen binding molecule may derive from or compete with hu24. For example, the PTK7-specific antigen binding molecule may be an immunoglobulin, an immunoglobulin Fab region, an Fv, a single chain Fv (scFv), a diabody, a triabody, a tetrabody, a VNAR domain, a single domain antibody (sdAb), a VH domain, or a scaffold protein (affibodies, centyrins, darpins etc.) that is derived from or competes with hu24. The PTK7-specific antigen binding molecule may comprise the CDRs of hu24. The PTK7-specific antigen binding molecule may comprise the VH and/or VL domains of hu24 The PTK7 specific antigen binding molecule may comprise an antibody or antibody fragment. For example, hu24 a humanised mouse IgG targeting PTK7 Ig domains 1-4 with an affinity of 1.2 nM for the full PTK7 extracellular domain [WO2015168019]. hu24 Fab LC variable region (SEQ ID NO: 548) EIVLTQSPATLSLSPGERATLSCRASESVDSYGKSFMHWYQQKPGQAPRLLIYRASNLES GIPARFSG SGSGTDFTLTISSLEPEDFAVYYCQQSNEDPWTFGGGTKLEIK hu24 Fab HC variable region (SEQ ID NO: 549) QVQLVQSGPEVKKPGASVKVSCKASGYTFTDYAVHWVRQAPGKRLEWIGVISTYNDYTYN NQDFKG RVTMTRDTSASTAYMELSRLRSEDTAVYYCARGNSYFYALDYWGQGTSVTVSS Wherein the PTK7-specific antigen binding molecule comprises a Fab, typically the PTK7-specific antigen binding molecule will comprise both a Fab LC and a Fab HC. The Fab HC may be fused to a fragment of an immunoglobulin Fc region. Typically, the Fab LC and the Fab HC are associated via a disulphide bond. For example, the PTK7-specific antigen binding molecule may comprise SEQ ID NO: 548 and SEQ ID NO: 549 wherein SEQ ID NO: 548 is be fused to a fragment of an immunoglobulin Fc region and wherein SEQ ID NO: 548 and SEQ ID NO: 549 are associated via a disulphide bond. Alternatively, the PTK7-specific antigen binding molecule may comprise the sequence of any PTK7- specific antigen binding molecule disclosed herein comprising: (i) at least 85% identity thereto, and/or (ii) one, two, or three amino acid substitutions relative thereto. Said sequence identity is at least about 85% sequence identity and may therefore be at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity. Preferably said sequence identity is at least 90% or at least 95%. The one or more amino acid substitution may be a conservative amino acid substitution. The term "conservative amino acid substitution", as used herein, refers to an amino acid substitution in which one amino acid residue is replaced with another amino acid residue having a similar side chain. Amino acids with similar side chains tend to have similar properties, and thus a conservative substitution of an amino acid important for the structure or function of a polypeptide may be expected to affect polypeptide structure/function less than a non-conservative amino acid substitution at the same position. Families of amino acid residues having similar side chains have been defined in the art, including basic side chains (e.g. lysine, arginine, histidine), acidic side chains (e.g. aspartic acid, glutamic acid), uncharged polar side chains (e.g. asparagine, glutamine, serine, threonine, tyrosine), non-polar side chains (e.g. glycine, cysteine, alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine, tryptophan) and aromatic side chains (e.g. tyrosine, phenylalanine, tryptophan, histidine). Thus a conservative amino acid substitution may be considered to be a substitution in which a particular amino acid residue is substituted for a different amino acid in the same family. However, a substitution of an epitope residue may equally be a non-conservative substitution, in which one amino acid is substituted for another with a side-chain belonging to a different family. The PTK7-specific antigen binding molecule may be humanized. The at least 85% identity and/or one, two, or three amino acid substitutions relative to the sequence of an PTK7-specific antigen binding molecule disclosed herein may comprise substitutions to humanize the PTK7-specific antigen binding molecule. More preferably, the PTK7-specific antigen binding molecule is selected from the group comprising 4H3, P2A7, E02 and 4D2. More preferably, the PTK7-specific antigen binding molecule is selected from the group comprising P2A7, E02 and 4D2. More preferably, the PTK7-specific antigen binding molecule is selected from the group comprising P2A7, and E02. More preferably, the PTK7-specific antigen binding molecule is selected from the group comprising 4D2, and E02. Most preferably, the PTK7-specific antigen binding molecule is selected from the group comprising P2A7 and 4D2. The PTK7-specific antigen binding molecule may comprise the amino acid sequence of P2A7. The PTK7-specific antigen binding molecule may comprise the amino acid sequence of 4D2. The PTK7-specific antigen binding molecule may comprise the amino acid sequence of 4H3. The PTK7-specific antigen binding molecule may comprise the amino acid sequence of E02. Preferably, the PTK7-specific antigen binding molecule selectively interacts with PTK7 protein with an affinity constant of approximately 1 to 2,000 nM or 2 to 2,000 nM, preferably 1 to 200 nM, even more preferably 1 to 20 nM. The affinity constant may be around 2 nM. An affinity constant may be measured as described elsewhere herein for ROR1-specific antigen binding molecule for instance by surface plasmon resonance (SPR) or by Bio-layer interferometry (BLI). It will be appreciated that the ROR1-specific antigen binding molecule and PTK7-specific antigen binding molecule may be combined in any order to form the bi-specific antigen binding molecule of the first aspect, i.e., the ROR1-specific antigen binding molecule may be N-terminal to the PTK7-specific antigen binding molecule or vice versa, or when the bi-specific antigen binding molecule is formed by Knobs-into-holes for example, the ROR1-specific antigen binding molecule may be on one arm while the PTK7-specific antigen binding molecule may be on the other arm or vice versa. Furthermore, it will be appreciated that higher-order constructs are also contemplated herein, for example constructs composed of multiple ROR1-specific antigen binding molecule and PTK7-specific antigen binding molecules. These may take the form of multiple copies in a single primary amino acid sequence, for example ROR1 binder-PTK7 binder-ROR1 binder or PTK7 binder-ROR1 binder-PTK7 binder. The bi-specific antigen binding molecule of the first aspect may additionally include a linker region between the ROR1-specific antigen binding molecule and PTK7-specific antigen binding molecule. Preferred linkers include but are not limited to [G ₄ S] _x , where x is 1, 2, 3, 4, 5, 5, 6, 7, 8, 9, or 10. Preferred linkers include [G4S]3, [G4S]5, and G4S. A preferred linker is [G4S]3. A preferred linker is G4S. A preferred linker is [G4S]5. Other linkers may include, but are not limited to PGVQPSPGGGGS (SEQ ID NO: 89) (Wobbe-G4S), PGVQPAPGGGGS (SEQ ID NO: 90) (Wobbe-G4S GM). It will be appreciated that different combinations of different linkers can be combined within the same construct. The bi-specific antigen binding molecule of the first aspect may also comprise additional domains, which may take the form of N-terminal or C-terminal additions or may be placed between the ROR1- specific antigen binding molecule and PTK7-specific antigen binding molecule in the amino acid sequence of the bi-specific binding molecule. Each domain of the bi-specific antigen binding molecule of the first aspect may be connected via linker regions as described above. Preferred additional domains include, but are not limited to an immunoglobulin, an immunoglobulin Fc region, an immunoglobulin Fab region, a single chain Fv (scFv), a diabody, a triabody, a tetrabody, a bispecific t- cell engager (BiTE), an intein, a VNAR domain, a single domain antibody (sdAb), a VH domain, or a scaffold protein (affibodies, centyrins, darpins etc.). A particularly preferred additional domain is an immunoglobulin Fc region, preferably a human Fc region. Combinations expressly contemplated in the present application include, but are not limited to Monovalent ROR1xPTK7 (Fc fusion) bi-specifics; Divalent ROR1xPTK7 (Fc fusion) bi-specifics; Monovalent ROR1xPTK7 (non-Fc) bi-specifics; Divalent ROR1xPTK7 (non-Fc) bi-specifics; Monovalent ROR1, half life extended ROR1xPTK7 (non-Fc) bi-specifics. Monovalent ROR1xPTK7 (Fc fusion) bi-specifics may adopt the format ROR1 binder – Fc – PTK7 binder or PTK7 binder – Fc – ROR1 binder. Divalent ROR1xPTK7 (Fc fusion) bi-specifics may adopt a format selected from the group consisting of: ROR1 binder - ROR1 binder -Fc- PTK7 binder ROR1 binder - PTK7 binder -Fc- ROR1 binder PTK7 binder - ROR1 binder -Fc- ROR1 binder PTK7 binder - PTK7 binder -Fc- ROR1 binder PTK7 binder - ROR1 binder -Fc- PTK7 binder ROR1 binder - PTK7 binder -Fc- PTK7 binder PTK7 binder -Fc- ROR1 binder - ROR1 binder ROR1 binder -Fc- PTK7 binder - PTK7 binder PTK7 binder -Fc- ROR1 binder - PTK7 binder PTK7 binder -Fc- PTK7 binder - ROR1 binder ROR1 binder -Fc- PTK7 binder - ROR1 binder, and ROR1 binder -Fc- ROR1 binder - PTK7 binder. Monovalent ROR1xPTK7 (non-Fc) bi-specifics may adopt the format ROR1 binder – PTK7 binder or PTK7 binder –ROR1 binder. Divalent ROR1xPTK7 (non-Fc) bi-specifics may adopt a format selected from the group consisting of: ROR1 binder - ROR1 binder - PTK7 binder ROR1 binder - PTK7 binder - ROR1 binder PTK7 binder - ROR1 binder - ROR1 binder Monovalent ROR1, half life extended ROR1xPTK7 (non-Fc) bi-specifics may adopt a format selected from the group consisting of: ROR1 binder -BA11- PTK7 binder ROR1 binder - PTK7 binder -BA11 BA11- ROR1 binder - PTK7 binder BA11- PTK7 binder - ROR1 binder PTK7 binder - ROR1 binder -BA11 PTK7 binder -BA11- ROR1 binder The ROR1 binder may be any ROR1 specific antigen binding molecule disclosed herein. Where two ROR1 binders are present, they may the same ROR1 specific antigen binding molecule or two different ROR1 specific antigen binding molecules. The PTK7 binder may be any PTK7 specific antigen binding molecule disclosed herein. Where two PTK7 binders are present, they may the same PTK7 specific antigen binding molecule or two different PTK7 specific antigen binding molecules. Where the linkers between domains are preferentially, but not limited to (G4S)X, where X is 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, PGVQPSPGGGGS (SEQ ID NO: 89) (Wobbe-G4S), PGVQPAPGGGGS (SEQ ID NO: 90) (Wobbe-G4S GM) and wherein different combinations of different linkers can be combined within the same construct. Whereby, additional C-terminal (or N-terminal) tag sequences may or may not be present. C-terminal tags include, but are not limited to, tags that contain poly-Histidine sequences to facilitate purification (such as His6), contain c-Myc sequences (such as EQKLISEEDL (SEQ ID NO: 112)) to enable detection and / or contain Cysteine residues to enable labelling and bioconjugation using thiol reactive payloads and probes and combinations thereof. Preferential C-terminal tags include but are not limited to. QASGAHHHHHHGAEFEQKLISEEDL (SEQ ID NO: 98) QACGAHHHHHHGAEFEQKLISEEDL (SEQ ID NO: 99) QACKAHHHHHHGAEFEQKLISEEDL (SEQ ID NO: 97) AAAHHHHHHGAEFEQKLISEEDL (SEQ ID NO: 100) ACAHHHHHHGAEFEQKLISEEDL (SEQ ID NO: 101) QASGAHHHHHH (SEQ ID NO: 102) QACGAHHHHHH (SEQ ID NO: 103) QACKAHHHHHH (SEQ ID NO: 104) AAAHHHHHH (SEQ ID NO: 105) ACAHHHHHH (SEQ ID NO: 106) QASGA (SEQ ID NO: 107) QACGA (SEQ ID NO: 108) QACKA (SEQ ID NO: 109) ACA (SEQ ID NO: 110) SAPSA (SEQ ID NO: 111) Domains may also be combined via N-terminal, C-terminal or both N- and C-terminal fusion to an Fc domain, including but not limited to: hIgG1 EPKSSDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKF NWYVDGV EVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQ PREPQVY TLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSK LTVDKSR WQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 216) hIgG1 (S239C) EPKSSDKTHTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKF NWYVDGV EVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQ PREPQVY TLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSK LTVDKSR WQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 217) hIgG1 (S442C) EPKSSDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKF NWYVDGV EVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQ PREPQVY TLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSK LTVDKSR WQQGNVFSCSVMHEALHNHYTQKSLCLSPGK (SEQ ID NO: 218) hIgG1 (S239C+S442C) EPKSSDKTHTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKF NWYVDGV EVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQ PREPQVY TLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSK LTVDKSR WQQGNVFSCSVMHEALHNHYTQKSLCLSPGK (SEQ ID NO: 219) It will be clear to those of skill in the relevant art that bi-specific antigen binding molecules comprising additional domains as described herein may, in some situations, include additional specificity beyond ROR1 and PTK7. Such configurations are also within the scope of the present invention. According to a second aspect, the invention provides a bi-specific antigen binding molecule comprising: (i) a receptor tyrosine kinase-like orphan receptor 1 (ROR1) specific antigen binding molecule comprising an amino acid sequence represented by the formula (I): FW1-CDR1-FW2-HV2-FW3a-HV4-FW3b-CDR3-FW4 (I) wherein CDR1 is a CDR sequence having an amino acid sequence selected from the group consisting of GTRYGLYS (SEQ ID NO: 25), GTRYGLYSS (SEQ ID NO: 26), DTRYALYS (SEQ ID NO: 27), DTRYALYSS (SEQ ID NO: 28), GTKYGLYA (SEQ ID NO: 29), GTKYGLYAS (SEQ ID NO: 30) and DTSYGLYS (SEQ ID NO:207); FW1 is a framework region; FW2 is a framework region; HV2 is a hypervariable sequence having an amino acid sequence selected from the group consisting of SSDEERISIS (SEQ ID NO: 31), STDEERISIG (SEQ ID NO: 32), SPNKDRMIIG (SEQ ID NO: 33), STDKERIIIG (SEQ ID NO: 34) and TTDWERMSIG (SEQ ID NO:208); FW3a is a framework region; HV4 is a hypervariable sequence having an amino acid sequence selected from the group consisting of NKGTK (SEQ ID NO: 35), NKGSK (SEQ ID NO: 36), NNGTK (SEQ ID NO: 37), NNRSK (SEQ ID NO: 38) and NKGAK (SEQ ID NO:209); FW3b is a framework region; CDR3 is a CDR sequence having an amino acid sequence according to REARHPWLRQWY (SEQ ID NO: 39); FW4 is a framework region; and (ii) a protein tyrosine kinase 7 (PTK7) specific antigen binding molecule. The ROR1 specific antigen binding molecule may be fused to a first fragment of an immunoglobulin Fc region and the PTK7 specific binding molecule may be fused to a second fragment of an immunoglobulin Fc region and the first fragment of an immunoglobulin Fc region and the second fragment of an immunoglobulin Fc region may be engineered to dimerise. As used herein the terms “first fragment” and “second fragment” are interchangeable. In preferred embodiments the ROR1-specific antigen binding molecule comprises an amino acid sequence selected from the group consisting of: TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVN (SEQ ID NO: 206) referred to herein as P3A1; TRVDQSPSSLSASVGDRVTITCVLTGTRYGLYSTYWYRKNPGSSDEERISISGRYSESVN KGTKSFTL TISSLQPEDSATYYCRAREARHPWLRQWYDGAGTKVEIK (SEQ ID NO: 77) referred to herein as P3A1 G1 AE3; TRVDQSPSSLSASVGDRVTITCVLTGTRYGLYSSTYWYRKNPGSSDEERISISGRYSESV NKGTKSFT LTISSLQPEDSATYYCRAREARHPWLRQWYDGAGTKVEIK (SEQ ID NO: 78) referred to herein as P3A1 G1 AE3.S; TRVDQSPSSLSASVGDRVTITCVLTDTRYALYSTYWYRKNPGSTDEERISIGGRYSESVN KGSKSFTL TISSLQPEDSATYYCRAREARHPWLRQWYDGAGTKVEIK (SEQ ID NO: 79) referred to herein as P3A1 G1 NAC6; TRVDQSPSSLSASVGDRVTITCVLTDTRYALYSSTYWYRKNPGSTDEERISIGGRYSESV NKGSKSFT LTISSLQPEDSATYYCRAREARHPWLRQWYDGAGTKVEIK (SEQ ID NO: 80) referred to herein as P3A1 G1 NAC6.S; TRVDQSPSSLSASVGDRVTITCVLTGTKYGLYATYWYRKNPGSPNKDRMIIGGRYSESVN NGTKSFTL TISSLQPEDSATYYCRAREARHPWLRQWYDGAGTKVEIK (SEQ ID NO: 81) referred to herein as P3A1 G1 NAG8; TRVDQSPSSLSASVGDRVTITCVLTGTKYGLYASTYWYRKNPGSPNKDRMIIGGRYSESV NNGTKSF TLTISSLQPEDSATYYCRAREARHPWLRQWYDGAGTKVEIK (SEQ ID NO: 82) referred to herein as P3A1 G1 NAG8.S; TRVDQSPSSLSASVGDRVTITCVLTGTKYGLYASTYWYRKNPGSTDKERIIIGGRYSESV NNRSKSFTL TISSLQPEDSATYYCRAREARHPWLRQWYDGAGTKVEIK (SEQ ID NO: 83) referred to herein as P3A1 G1 AF7.S; or a functional variant having CDR1, HV2, HV4 and CDR2 sequences according to any thereof and having FW1, FW2, FW3a, FW3b and FW4 sequences having a combined sequence identity of at least 45% to the combined FW1, FW2, FW3a, FW3b and FW4 sequences of any thereof. Particular advantages associated with affinity matured variants of P3A1G1 and functional variants thereof include improved binding to hROR1-Fc compared to parental P3A1G1 as illustrated by the Examples.

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^{I A} _L D ^{I S} _L D ^{I A} _L D ^{I A} _L D ^{I S} _L D ^{I A} _L D ^{I A} _L D ^{I A} _L D ^I 1 ^G _Y ^Q _E) ^G _Y ^Q _E) ^G _Y ^Q _E) ^G _Y ^Q _E) ^GQ ₎ ^GQ ₎ ^DQ ₎ ^GQ ₎ ^{GQ 1 1} _{YE YE YE YE YE)} R ^N _A ^S _{( :} ^N _A ^S _{( :} ^NS ₍ ³ _: ^NS ₍ ¹ _: ^NS ₍ ¹ _: ^NS ₍ ³ _: ^NS ₍ ⁴ _: ^NS ₍ ¹ _: ^NS ₍ ¹ _: D O O _A O _{A A A A A A A A A A} O AO AO O O O C G N G N G N G N G N G N G _A N G _A N G _A N D ^I D ^I D ^I D ^I D D D D D G G G G G ^I G ^I G ^I G ^I G ^{I T} _E ^{Q T} _E ^{Q T} _E ^{Q T Q TQ TQ TQ TQ TQ K} _E ^K _E ^K _{E E} K _{E E} K _{E E} K _{E E} K _{E E} K _{E EE T} ^S _{( T} ^S _{( T} ^S _{( T} ^S _{( T} ^S _T ^S _T ^S _T ^{S K} _T ^{S A} _T ^{A A A A} ₍ A _{( ( ( ( T} V _{TT V} ^V _{TT T T TT TT} ^A _TT ^A _TT ^A _TT R R _V R ^V _V R ^V _V R ^V _V R ^V _V R ^V _V R ^V R ^{V P} _T ^{P P P P P P P} _V ^P _V C ⁾ _T C ⁾ _T C ⁾ _T C ⁾ _T C ⁾ _T C ⁾ _T C ⁾ _T C _T C Q ^N _{I 0} Q 4 ^N _{I 0} Q 4 ^N _{I 0} Q 4 ^N _{I 0} Q 4 ^N _{I 0} Q 4 ^N _{I 0} Q 4 ^N _{I 0} Q ^{) 4 N} _{I 0} Q ^{) 4 N} _{I 0 1} ^N _V ^T _{L :} ^N _V ^T _{L :} ^N _V ^T _{L :} ^N _V ^T _{L :} ^N _V ^T _{L :} ^N _V ^T _{L :} ^N _V ^T _{L :} ^N _V ^T _{L :} ^N _V ^T _L ⁴ _: W _F ^S _A ^S _E O ^S _A ^S _E O ^S _A ^S _E O ^S _A ^S _E O ^S _A ^S _E O ^S _A ^S _E O ^S _A ^S _E O ^S _A ^S _E O ^S _A ^S O N N N N N N N N _E N e _P m ² a _{1 P} C ^G _{5 4 9 8} C 1 _P F ^{G H} ₁ ^C _{9 6} ⁰ ₁ N ₁ G _{2 1 1} G D ^B ₁ ^F ₁ N N P ^D _I P ^D _I P ^D P ^D P ^D P ^D P ^D P ^D P ^{D N N N} _I N _{I I I I I I K K K K} ^N _K ^N _K ^N _K ^{N N R} _Y ^Q _E ⁾ ₃ ^RQ _E ⁾ ₃ ^RQ _E ⁾ ₃ ^{R Q} _E ⁾ ₃ ^RQ _E ⁾ ₃ ^RQ _E ⁾ ₃ ^RQ _E ⁾ _{K 3} ^RQ _E ⁾ _{K 3} ^RQ _E ⁾ W ^S ₍ ⁴ _{: Y} ^S ₍ ⁴ _{: Y} ^S ₍ ⁴ _{: Y} ^S ₍ ⁴ _{: Y} ^S ₍ ⁴ _{: Y} ^S ₍ ⁴ _{: Y} ^S ₍ ⁴ _{: Y} ^S ₍ ⁴ _{: Y} ^S _{3 (} ⁴ _{: T} O W O W W W W W W W Y G N ^Y _T G N ^Y _T O G N ^Y _T O G N ^Y _T O O O O O G N ^Y _T G N ^Y _T G N ^Y _T G N ^Y _T G N S _L D ^{I A} _L D ^{I A} _L D ^{I A} _L D ^{I S} _L D ^{I A} _L D ^{I A} _{S L} ^{I A} _L D ^{I A} _L D ^{I G} _Y ^Q _E) ^DQ ₎ ^{DQ 3} _YE ⁴ _YE) ^{GQ 4} _YE) ^G _Y ^Q _E) ^G _Y ^Q _{E )} ^G _Y ^Q _E) ^G _Y ^Q _E) ^G _Y ^Q _E) N _A ^S _{( :} ^N _A ^S _{( :} ^N _A ^S _{( :} ^N _A ^S ₍ ¹ _: ^NS ₍ ³ _: ^NS ₍ ¹ _: ^NS ₍ ⁵ _: ^NS ₍ ¹ _: ^NS ₍ ⁵ _{: A} O AO AO AO _{A A} O _{A A} O _{A A A} O AO _{A A} O G N G N G N G N G N G N D N G N D N D ^I D ^I D ^I D ^I D ^I D ^I D ^I D ^I D G G G G G G ^G _V G ^G _V ^{I T} _E ^{Q T} _E ^{Q T} _E ^{Q T} _E ^{Q T} _E ^{Q T} _E ^{Q Q T} _E Q ^{Q K} _E S ^K _E S ^K _E ^K _E ^K _E ^K _E ^S _AE ^KE _S ^S _{AE T} A _{( T( T} ^S _{( T} ^S _{( T} ^S _{( T} ^S ₍ ^SS _{( S} ^{( S} _{( TT} ^{A V} _TT ^A _TT ^A _{T T} ^A _TT ^A _{TT L T} ^{A S} _{L T} R R ^V R ^V R ^V R ^V R ^{V S} _S ^L _S R ^T _V ^S _S ^{L P} _TV C ^P Q ^N) _TV C ^{P )} _TV C ^P _V ^P _V ^P _V ^P _V ) _T C ⁾ _T C ⁾ _T C ⁾ _S C ^P R ^P _V C T ⁾ _S C ⁾ _S ^{) N} _{I 0} Q V ^{T S} _L ^{4 N} _{I 0} Q : ^N _V ^T _L ^{4 N} _{I 0} Q : ^N _V ^T _L ^{4 N} _{I 0} Q : ^N _V ^{T 4 N} _{I 0} Q : ^{NT 4 N} _{I 0} Q : ^{NT 4} _{I :} ^DT _{1 V} ⁴ Q ^T _{I 2} Q ^T : ^{TT 4} _{I :} ^DT _{1 V} ⁴ _{: A} ^S _E O O O _{L VL VL V VL V} N ^S _A ^S _E N ^S _A ^S _E N ^S _A ^S _E O N ^S _A ^S _E O N ^S _A ^S _E O N ^R _T RO ^S _A ^S _E O ^R _T RO D N N D N P _{P 4 P P P} G C _{P P} 6 C C ₁ ^C ₀ ^C _{5 8 E} ² _F ⁶ _B ^G ₁ ¹ ₃ ^C ₃₄ ^C _{3 A} G G G G ¹ _V ^H ₁ ^A _S ^A _S ^{l a} _{f S} ^A _S ^A _S Q D _{e E} ^EQ _E ^D _E ^Q _E ^{b o} D D e ^AQ _E ^{E Q} D E ^EQ _E S _{P (} ^Q _L ^S ₍ ^V _T ^{2 L S} _{c V (} ^e _l ^{n TS} _{P (} ^QS _{P (} ^QS ₍ A ^S _S ^b _{e L L L a} ^u D ^{S S} K ⁾ _S ^I _A ^{) S} _I ^A _{q K} ^{) T e K} _I ^A) _S ^I _A ⁾ _S ^I _A ^{) C} _{7 Y} ⁴ _T R _{6 :} ^L _T ^C _Y ⁴ R _{7 :} ^L _S ^C _Y ⁴ _: ^{n i} _{s d} ^b R _{K4 3} ^L _S ^C _Y ⁸ _T R _{6 :} ^L _T ^C _Y ⁴ _T R _{6 :} ^{L C 4} _: Y _T O ^F _S ^Y _T O ^FY O ^t _u ^e _n ^{W FY} O ^{F Y} O _T F _Y YO N N _{S T} N ^o _{F S T} N _{S T S T : : :} ^t N N e ⁱ _b m _{: : :} O O O ^{s N N N e} _n ^o _c O O O N ^{N N D} I ^MD I ^MD I _l ^o _e h ^{KD I KD I KD I} E ^{) R ) R ) r} _p ^p _s ^{1 R ) R ) S} _{3 (} ⁴ _{: YE} W ^S _{3 (} ⁴ _{: YE} S ₃ ^R ( ⁴ _: ^{m -} _{1 2 FE} S _{( 2} 2 _{: YE} S _{3 (} ⁴ _{: YE} S _{3 (} ⁴ _: O W _o R W W W Y O ^Y O ^{c y} O ^{W S} O ^Y O ^Y O G N _T G N _T G N _{F T} G _{T T a} R ^s _e N G N G N D ^{I A} _L D ^{I A} _L D ^I m _e ^c e ^{h t} _n ^Y D ^I ₎ ^Y _L D ^{I YQ} _E ⁾ ₆ Q _E) ^{G l} Y ^Q _E) ^G _Y ^Q _{E) u} ^, _n ^e _{u L} ^{7 )} _L q ₁ ^G _Y ^Q _E0 ^G _Y ^Q _E5 ^G _Y ^S ₍ ² _: S ₍ ¹ _: ^NS ₍ ⁵ _: ^{NS 1} _: ^c _{e i} ^o _e R ^{S 2} _: ^{S 2} _: O A ₍ ^{l t s S} ₍ ^R _{T (} ^R _T ^N AO _A O O N D _A N G _A N _{o n} m ^e _v ^t D _T O O n C D _S N G _S N G ^S _S ^D _I D ^{g n} i ^{ai I} D ^I D ^I _n ⁱ _r D ^I D ^I D G _V G _d ^e _h ^a _v G ^G _V ^G _V ^I Q ^{Q T} _E Q _i ^{n t T} _E ^{Q Q Q E S} _E ^b _{f 1 E} ^S _AE ^S _{AE S} ⁽ _A S ^S ₍ ^K _S ^E _S ^{( n o} _t ^G ₁ ^K _T ^S ₍ ^S _L ^S ₍ ^SS ₍ T _{L V} ^{S A} S _S ^T _e g ^{c A} _{L T} ⁱ _{t e} A 3 _TT ^S _{S T} L ^S _ST L R ^L C ^P _V R _V ^{p P} R ⁿ _{a s P} R ^{L P} _TV ^P _{V V S} C ^P C T _I ⁾ _S C 2 Q ^T _I ⁾ _{S 1} C Q ^{T T} _I ⁾ _{2 c} ^a _d C ₎ i _{f L} ⁴ _: ^D _V ^T _V ⁴ _: ^{TT 4} _{: i} ^d _n ⁿ _a Q ^N0 Q ^T _I ⁾ _{S 1} ^D _{I 2 V} ^T _L ² _: ^D _V ^T ₁ Q ^T V ⁴ _I ⁾ : ^D _V ^T _{1 V} ⁴ _: SO _VL ^{c R} RO ^SS O _e ^o _{c 1} A ^W _F ^RS O ^R RO ^R RO E N _T D N _{A E} N ^p _s ^e _{T E} N _T D N _T D N - _{s 1 r} ³ _{P 5} ^o _{/ – 1 1} 1 R V _{8 P P} O ^d _{n . 2} ^{G G C} _e ^e _n e ^{1 1 1} _S ^. 3 ₄ ^C ₃₅ R ^a w 1 _e ^t _l ^{o l} _b ^o _l ^m _{a A} 3 _{A3 A3} H ₁ C G C _V ^h _{s T} ^ri _f ^e _b ^a _T C N _P ³ _P ^E _A ³ _P ^E _A : _{: : : :} O O O O O ^D _I ^D _I ^D _I N ^{N N N N} _{) ) )} K ^{KD I KD I KD I KD I KD I} _A ⁹ ₀ ^{K 2} _A ⁹ ₀ ^{K 9 2} _{A 0} 2 N _K ^N _K ^N _K ^N _K ^N _K ^N _{K )} ^N _{K )} ^N ₎ R _Y ^Q _E ⁾ ₃ ^RQ _E ^{) RQ) R Q) RQ) Q1 Q1} _K ^Q1 W ^S ₍ ⁴ _{: Y} W ^S _{3 (} ⁴ _{: YE} W ^S _{3 (} ⁴ _{: YE} W ^S _{3 (} ⁴ _{: YE} W ^S ₃ ^R ( ⁴ _{: 2 F E} S ₂ ^R ( ² _{: FE} S ₂ ^R ( ² _{: FE} S _{2 (} ² _{: T} O O _s W W W Y O O O O O O G N ^Y _T G N ^Y _T G N ^Y _T G N ^Y _T G N ^e _c ^W _F ^S _T G N ^S _T G N ^S _T G N n D ^Q) D ^{Q) )} _e u ^D _{I : T:} Y _L ^{I Y} _{L E8} ^Y _L ^{I Y} _{L E0} ^Y _L ^Q _{E0 q} V _S O MO A _Y ^Q _E ⁾ ₇ ^A _Y ^S ₍ ² _: ⁾ O ^G _Y ^Q _E9 ^G _Y ^S ₍ ³ _: ^S O ^G _{Y (} ³ _: ^e W ₎ ^Y _L ^N D ^N O _s ^Q6 ₁ ^D I ^ED I R ^S ₍ ² _: ^{R 2 N KS} _{( :} ^{K N K N} _e ^l ₁ ^W _{P E} ^G _{Y E T} O _T D _S N D ^S _{T S} ^D _I O _T G _A N G ^S _{T A} ^D _I G ^S _{u A} ^D _I ^c R e ^DS ₍ ⁶ _: ^NQ) ₅ ^WQ) ₃ l D _T O _{TE TE o} C D R N D ^S ₍ ¹ ₆ D ^S ₍ ¹ ₆ GD V ^{I G} D ^I D D D S _V ^G _V ^{I G} _V ^{I G} _V ^{I m g T Q} _E ^TQ _E ^TQ _{E A} ^Q _E ^S _A ^Q _E ^SQ _E ^{S Q} _E ^SQ _{E n} ⁱ _E ^S _E ^S _E ^{S SS} ₍ ^SS _{( A} ^S _{( A} ^S _{( A} ^S _{( d} ^K _{T (} ^K _T( ^K _{T( L T L} ^S T _L ^S T _L ^S _{i T L T} ^{n b A} _{T T} ^A _TT ^A _TT S _S ^{L S} V _S ^{L S} V _S ^{L S} V _S ^{L S} V _S ^L _V ^c _fi R ^L _V) ^L SC _S C _S C _S C _S C ^{c 8} R _V) ^{L 0} R _V) P ^{P P P P P} C ₉ C ₂ C ⁹ ₉ Q ^T _I ⁾ Q ^T _I ⁾ Q ^T _I ⁾ Q ^T _I ⁾ Q ^T _I ⁾ _{e T} Q ^N _I ^{P P 5} _{: T} ^N _I ² _{: T} ^N _I ⁵ _: D _V ^T _{1 V} ⁴ _: ^D _V ^T _{1 V} ⁴ _: ^D _V ^T _{1 V} ⁴ _: ^DT _{1 V} ⁴ _: ^DT _{1 V} ⁴ _: ^p _{s 1} ^NT _L Q O ^DT _L Q O ^DT _L O R _T RO D N ^R _T RO D N ^R _T RO _V D N ^R _T RO _V D N ^R _T RO - _{7 V} ^S D N ^K _T ^W _E ^N _V ^S _E ^N _V ^S _E ^N F ^S _A G ^D _I ^R _T G ^D _I ^S _A G ^D _{I 1 1 1 1 1} ^{P G} _{S S :} 5 ¹ ₆ ^G. A ¹ ₆ ^{G 1} ₈ ^{G. 1} ₈ ^{G 1} _S ^. ₄ ^e _n e ^{2 7 1 3 C} _{A A} ^C _{A A} ^G _{A A} ^G _{A A7 e} ^l _b ^o _l ^m _{a A A B P} N ³ _P N ³ _P N ³ _P N ³ _P ^F _A ^{a 2 2 2} T C N _{P P P} P P P P P P P P P N _K ^D _{I )} ^ND _{I )} ^ND _{I )} ^ND _{I )} ^ND _{I )} ^ND _{I )} ^ND _{I )} ^ND _{I )} ^ND _{I )} R _F ^Q _E ¹ _K R _F ^Q1 _K R _F ^Q1 _K R _F ^Q1 _{K K K K K 2 2 2 2} ^{R Q1} ₂ ^RQ1 ₂ ^{R Q1} ₂ ^RQ1 ₂ ^RQ1 ₂ W ^{S 2} _{: E} W ^{S 2} _{: E} W ^{S 2} _{: E} W ^{S 2} _{: F E} W ^{S 2} _{: FE} W ^{S 2} _{: F E} W ^{S 2} _{: FE} W ² _{: FE} W ² _: S ( T O G N ^S ( T O G N ^S ( T O G N ^S ( T O ( O ( O ( O ^S ( O ^S ( O G N ^S _T G N ^S _T G N ^S _T G N ^S _T G N ^S _T G N A _{: : :} PO ^T O ^K _{: : : :} O _{T T V} ^N _P W ^N _P ^L W ^N _E O N HO O NO N ^{Y N Y N} Y S ^D _I Q ^D _{L L} W ^D _{I )} ^W ₎ D ^{D D} _T ^{D V} _P ^D G ⁸ _S ⁹ D ^I G D ^{I W} _V ^{I I I} D ^{D I} G ^{D I} C ^Q ₀ C ^Q _{E 0} D ^Q _E ⁾ ₁ ^DQ _E ⁾ ₂ ^EQ _E ⁾ ₃ W T ^Q _E ⁾ D 4 ^DQ _E ⁾ H 5 ^NQ _E ⁾ C 6 ^{S Q} _E ⁾ ₇ ^R _E ^{6 S} _: ^{SS 6} _{: T T T T T T T A(} O _A ( S ^{0 S0 S0 S0 0 0} D ⁰ O D _{( 6} D _{( 6} D _{( 6} D _{( 6} D ^S _{( 6} D ^S _{( 6} ^S _{( 6} G _S N G G N T _E Q ^{TQ TQ T} Q ^{T Q T T Q TQ TQ K} _T ^E _{EE S} ^K _T ^S _{EE E (} ^K _T ^S ₍ ^K _T ^E _{E E E} Q S ^K _T ^S ₍ ^KE _{E E EE S} ^KS ₍ ^KS _{EE (} ^KS ₍ A _TT ^A _TT ^A _T ^A _T ^A _{T T} A _{T T} A _{T T} A _{T T} A _T R ^L _V) ^{L 8} R _{V) T} ^{L 0} R _{V) T} ^{L 0} R _{V) T} ^{L 8} R _{V) T} ^{L 0} R _{V) T} ^{L 8} R _{V) T} ^V _T ^{V 0} R _V R _V P _T C N _{I 9} ^P _T C N ₂ ^P _T C N ₂ ^P _T C N ₉ ^P _T C N ₂ ^P _T C N ₉ ^P _T C N ₂ ^P _T C ^{) N} ₀ ^P _T C ^{) N} ₀ Q ^{T 5} L _: Q _I T ² L _: Q _I T ² L _: Q _I T ⁵ _: Q _I T ² _: Q _I T ⁵ _: Q _I T ² _: Q _I T ⁴ _: Q _I T ⁴ _: N _V ^S O N ^D _V ^S O N ^D _V ^S O N ^N _{L V} ^S O N ^D _{L V} ^S O N ^N _{L V} ^S O N ^D _{L V} ^S O ^N _{L V} ^S O ^N _{L V} ^S O S _E G ^{D R} _E G ^{D R} _E G ^{D S} _E G ^R _E G ^S _E G ^R _E ^N G ^S _E ^N G ^S _E ^N A _{I T I T I A} ^D _{I T} ^D _{I A} ^D _{I T} ^D _{I A} ^D _{I A} G ^D _I e ₂ m ¹ _{3 a B 6 7} C ⁸ _{F 9} ² _{1 7 5} N ² _P ² C P ² _P ² G P ² H P ² _P ^A ₄ ^C ₄ ^E ₄ ) ₎ ^{e n} _g K _A ⁹ ₀ ⁹ _{) n e i} ^{n D} I ^D I ^D I ^D I ⁹ _i ^g _i ^{n G 2 M} ₎ ^K : _T ⁸ _{: A 0} ^{K 2} _{0 l} ^o : _A ² _: ^{c t} _{n K} ^Q _E ^m O ^R _K ^Q _E O ^G _K ^Q _E O ^G _K ^Q _{E r} O ^{a a} N ^S ₍ N N ^S ₍ N N ^S ₍ N N ^S ₍ N ^f _o ^ci _f ^e _{t s} ⁱ _c ^e _{d V} ^e _y S _V D ^S _{V V} ^e _{c p} ^{t s i} _{r E} ⁾ _E ^{) S} _E ^{) S} _E ^{) n} - ^{a V} _{I 4} ^D Y ^{Q 4} _: ^V _{I 4} ^D Y ^{Q 4} _: ^V _{I 4} ^D Y ^{Q 4} _: ^V _{I 4 Y} ⁴ _{e :} ^u _q ⁷ _{t K} ⁿ _e R _E O R _E O R _E ^Q O R _E ^T G ^S ₍ N G ^S ₍ N G ^S ₍ N G ^S ₍ O N ^e _{s P} ^m _e ⁸ V _e ^l ₄ S S ^{h t} _p S I ^{H m} M ^{D R I} ₎ ^S _I M ^{D f I} M ^{D I d} _{n o o} c E ^{D Q8} ₀ ^R _{I E )} ^R _{) E} ^{Q8 R} _{) E} ^{Q8 a} _s e ^, _s W _E D ^S ₍ ² _: Q ^Q N _E ⁶ _: W _E0 S ² _{E0 :} W ² _: R _c n ⁿ _o T ^S T ^G _I O N ^S _{( S S} O D ₍ D ^S ₍ N ^T D _e ⁱ T ^G _I O N ^T _T ^G _I O N C e ^u _{g q} ^{e e} _{r s k} P P P P ^h _{t ll} ^{r N} _K ^D _{I )} ^N _K ^D _I ^N _K ^D _{I )} ^ND _{e I ) i} ^{s u} _{o f} ^{w R} _F ^Q _E ¹ Y ^Q) _K R _F ^{Q R Q} ₂ ^r _{e e 2} ^R ₃ ¹ ₂ ¹ _p ^{h m} W ^{S 2} _{: E} W ^{S 4} _{: E} W ^{S 2} _{: F E} W ^{S 2} _: ^m t S ( O ^Y ( O ^S ( O ( O _{o a} ^r f G N ^c m T G N _T G N _T G N ^S _T ^{y o} r _f ^e _{h : : : a s} ^t _f S _Y O _A O _T O ^H _: O m ^e _c ^o W ^{N A} _L ^N M D ^N _V N _e ^{l n s D E AD ED} _P ^D _{u e n} G ^I _Y ^I _E ^I G ^{I c u} _{q i} ^o C ^I _A ^Q _E1 ^{GQ) Q) Q)} _e ^l _o ^{e t} _a S ¹ _AE2 ^{W S1} _TE3 ^{W 1} _{T E4} 1 ^m _s ^t _u G _{( 6} G _{( 6} D ^S _{( 6} D ^S _{( 6} g _{V n} ^H m ^r _e T _E ^{Q i} E ^T _d ^d _n ^{p K} _E ^Q _E ^T _E Q ^T Q ^. T ^{S K} _{E i ( T} ^S ₍ ^K _T ^E _S ^{KE n} S ^{b a d} R _{n n} ⁱ _e A _{T T} ^A _T ^A _{T T} A _T ⁿ D ^{a r} _e R ^V _{V T} R ^V _{V T} R ^L _{V) T} R ^L _{e V) i} ^g C ^s _n o ^{h P} _T C ⁾ ₀ ^P _T C ⁾ ₀ ^P C ⁸ ₉ ^P C ⁸ ₉ ^t _{n e} h ⁱ _t ^d _e Q ^N _I ⁴ _: Q ^N _I ⁴ _{: T} ^N _I ⁵ _{: T} ^N _I ⁵ _: ^a _t ^a _n ^t _a N ^T _{L V} ^S O ^NT _L Q O ^NT _L Q O ^T _L O ^c i _{f y} ^{fi i} _b ^l _p S _E ^N _V ^S _E ^N _V ^{S N} E ^N _V ^S _E ^{N i} _{c t A} ⁿ G ^D _I ^S _A G ^D _I ^S _A G ^D _I ^S _A G ^D _I ^e _{p e} m ^{m s} - ^d _e i ^o _c ^t _n 7 ⁿ _{e a} ^{l o} _{c K b} ⁱ 2 ^{T c} _{s y} ^l _{ti 2 P} ⁿ _o ^s _{o i} D _{2 4} ⁰ _{4 E} ^B _P ^C _{P e} ^{s h} _r ^{p c} l ^l _{p T} ^e _p ^l _A ^x _e Sequence identity referenced in relation to the molecules of the invention may be judged at the level of individual CDRs, HVs or FWs, combined CDRs, HVs or FWs, or it may be judged over the length of the entire molecule. The CDR, HV and FW sequences described may also be longer or shorter, whether that be by addition or deletion of amino acids at the N- or C-terminal ends of the sequence or by insertion or deletion of amino acids with a sequence. Framework region FW1 is preferably from 20 to 28 amino acids in length, more preferably from 22 to 26 amino acids in length, still more preferably from 23 to 25 amino acids in length. In certain preferred embodiments, FW1 is 26 amino acids in length. In other preferred embodiments, FW1 is 25 amino acids in length. In still other preferred embodiments, FW1 is 24 amino acids in length. In alternative definitions, CDR region CDR1 is preferably from 7 to 11 amino acids in length, more preferably from 8 to 10 amino acids in length. In certain preferred embodiments, CDR1 is 9 amino acids in length. In other preferred embodiments, CDR1 is 8 amino acids in length. Framework region FW2 is preferably from 6 to 14 amino acids in length, more preferably from 8 to 12 amino acids in length. In certain preferred embodiments, FW2 is 12 amino acids in length. In other preferred embodiments, FW2 is 10 amino acids in length. In other preferred embodiments, FW2 is 9 amino acids in length. In other preferred embodiments, FW2 is 8 amino acids in length. In alternative definitions, Hypervariable sequence HV2 is preferably from 4 to 11 amino acids in length, more preferably from 5 to 10 amino acids in length. In certain preferred embodiments, HV2 is 10 amino acids in length. In certain preferred embodiments, HV2 is 9 amino acids in length. In other preferred embodiments, HV2 is 6 amino acids in length. Framework region FW3a is preferably from 6 to 10 amino acids in length, more preferably from 7 to 9 amino acids in length. In certain preferred embodiments, FW3a is 8 amino acids in length. In certain preferred embodiments, FW3a is 7 amino acids in length. In alternative definitions, Hypervariable sequence HV4 is preferably from 3 to 7 amino acids in length, more preferably from 4 to 6 amino acids in length. In certain preferred embodiments, HV4 is 5 amino acids in length. In other preferred embodiments, HV4 is 4 amino acids in length. Framework region FW3b is preferably from 17 to 24 amino acids in length, more preferably from 18 to 23 amino acids in length, still more preferably from 19 to 22 amino acids in length. In certain preferred embodiments, FW3b is 21 amino acids in length. In other preferred embodiments, FW3b is 20 amino acids in length. In alternative definitions, CDR region CDR3 is preferably from 8 to 21 amino acids in length, more preferably from 9 to 20 amino acids in length, still more preferably from 10 to 19 amino acids in length. In certain preferred embodiments, CDR3 is 17 amino acids in length. In other preferred embodiments, CDR3 is 14 amino acids in length. In still other preferred embodiments, CDR3 is 12 amino acids in length. In yet other preferred embodiments, CDR3 is 10 amino acids in length. Framework region FW4 is preferably from 7 to 14 amino acids in length, more preferably from 8 to 13 amino acids in length, still more preferably from 9 to 12 amino acids in length. In certain preferred embodiments, FW4 is 12 amino acids in length. In other preferred embodiments, FW4 is 11 amino acids in length. In still other preferred embodiments, FW4 is 10 amino acids in length. In yet other preferred embodiments, FW4 is 9 amino acids in length. In one embodiment of the ROR1-specific antigen binding molecule: FW1 is a framework region of from 20 to 28 amino acids; FW2 is a framework region of from 6 to 14 amino acids; FW3a is a framework region of from 6 to 10 amino acids; FW3b is a framework region of from 17 to 24 amino acids; and/or FW4 is a framework region of from 7 to 14 amino acids. In one embodiment of the ROR1-specific antigen binding molecule: FW1 has an amino acid sequence selected from the group consisting of: ASVNQTPRTATKETGESLTINCVVT (SEQ ID NO: 40), TRVDQSPSSLSASVGDRVTITCVLT (SEQ ID NO: 41) and ASVTQSPRSASKETGESLTITCRVT (SEQ ID NO: 42), or a functional variant of any thereof with a sequence identity of at least 45%; FW2 has an amino acid sequence according to TYWYRKNPG (SEQ ID NO: 43), or a functional variant of any thereof with a sequence identity of at least 45%; FW3a has an amino acid sequence selected from the group consisting of: GRYVESV (SEQ ID NO: 44) and GRYSESV (SEQ ID NO: 45), or a functional variant of any thereof with a sequence identity of at least 45%; FW3b has an amino acid sequence selected from the group consisting of: SFSLRIKDLTVADSATYYCKA (SEQ ID NO: 84), SFTLTISSLQPEDSATYYCRA (SEQ ID NO: 46) and SFSLRISSLTVEDSATYYCKA (SEQ ID NO: 47), or a functional variant of any thereof with a sequence identity of at least 45%; and/or FW4 has an amino acid sequence selected from the group consisting of: DGAGTVLTVN (SEQ ID NO: 48), DGAGTKVEIK (SEQ ID NO: 49) or DGQGTKLEVK (SEQ ID NO: 85) or a functional variant of any thereof with a sequence identity of at least 45%. The ROR1-specific antigen binding molecule may be humanized. The ROR1-specific antigen binding molecule may be de-immunized. The B1 loop variants on the humanised backbones G4 and V15 described herein are humanised. As P3A1G1 is already humanised all loop variants of P3A1G1 are humanised. Examples of humanised sequences of the invention include, but are not limited to: B1G4 G3CP G4 G3CP V15 1H8 G4 1H8 V15 C3CP G4 C3CPV15 P3A1 G1 AE3 P3A1 G1 AE3.S P3A1 G1 NAC6 P3A1 G1 NAC6.S P3A1 G1 NAG8 P3A1 G1 NAG8.S P3A1 G1 AF7.S It will be appreciated by the skilled person that the humanised ROR1-specific antigen binding molecules described herein may be further humanised, for instance by substituting further FW region amino acids with amino acids of DPK-9. The ROR1-specific antigen binding molecule may also be conjugated to a detectable label, dye, toxin, drug, pro-drug, radionuclide or biologically active molecule. Preferably, the ROR1-specific antigen binding molecule does not bind to receptor tyrosine kinase-like orphan receptor 2 (ROR2). More preferably, the ROR1-specific antigen binding molecule binds to both human ROR1 and murine ROR1 (mROR1). Yet more preferably, the ROR1-specific antigen binding molecule binds to deglycosylated ROR1. Certain ROR1-specific antigen binding molecules of the invention may not bind to a linear peptide sequence selected from: YMESLHMQGEIENQI (SEQ ID NO: 91) CQPWNSQYPHTHTFTALRFP (SEQ ID NO: 92) RSTIYGSRLRIRNLDTTDTGYFQ (SEQ ID NO: 93) QCVATNGKEVVSSTGVLFVKFGPPPTASPGYSDEYE (SEQ ID NO: 94) Preferably, the ROR1-specific antigen binding molecule selectively interacts with ROR1 protein with an affinity constant of approximately 0.01 to 50 nM, preferably 0.1 to 30 nM, even more preferably 0.1 to 10 nM. An affinity constant may be measured by Bio-layer interferometry (BLI). For monomers the interaction is 1:1. For the VNAR-hFc format the inventors have used two approaches. One where the ROR1 is immobilized and thus a bi-valent VNAR-hFc binds with an apparent KD as the avidity effect comes into play. The other approach is in a 1:1 format whereby the VNAR-hFc is immobilized and ROR1 is flowed across the surface thus giving the K _D for ‘true’ 1:1 binding. Typically, where used herein affinity constants refer to those measured by Bio-layer interferometry (BLI) using the 1:1 binding format. By this method, for example, G3CP and G3CP G4 are within the 0.1 – 10 nM range. Of the P3A1 G1 loop variants examples have KD values of 5.0 nM (AE3), 13.8 nM (NAC6) and 12.2 nM (NAG8). Optionally, the antigen binding molecule specifically binds ROR1 with an affinity determined by SPR, (e.g., under SPR conditions disclosed herein). Similarly, the antigen binding molecule may specifically bind PTK7 with an affinity determined by SPR, (e.g., under SPR conditions disclosed herein). Such binding measurements can be made using a variety of binding assays known in the art, e.g., using surface plasmon resonance (SPR), such as by Biacore ^TM or using the ProteOn XPR36 ^TM (Bio-Rad®), using KinExA® (Sapidyne Instruments, Inc), or using Bio-layer interferometry (BLI) such as Octet system (Sartorius). ROR1 or PTK7 binding ability, specificity and affinity (KD, koff and/or kon) can be determined by any routine method in the art, e.g., by surface plasmon resonance (SPR) or Bio-layer interferometry (BLI). The term “kon” or “ka” as used herein refers to the association constant. The term “kd” or “koff” as used herein refers to the dissociation constant. The term “K _D ”, as used herein, is intended to refer to the equilibrium dissociation constant of a particular antibody-antigen interaction. Such binding measurements can be made using a variety of binding assays known in the art, e.g. using surface plasmon resonance (SPR), such as by Biacore ^TM or using the ProteOn XPR36 ^TM (Bio-Rad ^® ), using KinExA ^® (Sapidyne Instruments, Inc), or BLI using Octet system (Sartorius). In one embodiment, the surface plasmon resonance (SPR) is carried out at 25 ^o C. In another embodiment, the SPR is carried out at 37 ^o C. In one embodiment, the SPR is carried out at physiological pH, such as about pH7 or at pH7.6 (e.g., using Hepes buffered saline at pH7.6 (also referred to as HBS-EP)). In one embodiment, the SPR is carried out at a physiological salt level, e.g., 150mM NaCl. In one embodiment, the SPR is carried out at a detergent level of no greater than 0.05% by volume, e.g., in the presence of P20 (polysorbate 20; e.g., Tween-20 ^TM ) at 0.05% and EDTA at 3mM. In one example, the SPR is carried out at 25 ^o C or 37 ^o C in a buffer at pH7.6, 150mM NaCl, 0.05% detergent (e.g., P20) and 3mM EDTA. The buffer can contain 10mM Hepes. In one example, the SPR is carried out at 25 ^o C or 37 ^o C in HBS-EP. HBS-EP is available from Teknova Inc (California; catalogue number H8022). In an example, the affinity of the antibody or fragment is determined using SPR by 1. Coupling target antigen (e.g. ROR1 or PTK7) to a biosensor chip (e.g., GLM chip) such as by primary amine coupling. Alternatively target antigen may be coupled indirectly to biosensor chip via an initial anti-tag IgG capture step (e.g. appropriate anti-Fc IgG) 2. Passing the test ROR1 x PTK7 bispecific over the chip’s capture surface at 1024nM, 256nM, 64nM, 16nM, 4nM with 0nM (i.e. buffer alone); 3. Determining the affinity of binding of test ROR1 x PTK7 bispecific to target antigen using surface plasmon resonance, e.g., under an SPR condition discussed above (e.g., at 25 ^o C in physiological buffer). SPR can be carried out using any standard SPR apparatus, such as BiacoreTM or using the ProteOn XPR36TM (Bio-Rad®). Alternatively, test ROR1 x PTK7 bispecific may be coupled to biosensor chip directly (e.g. primary amine coupling) or indirectly via an initial anti-tag IgG capture step (e.g. anti-hFc IgG) and passing the target antigen (e.g. ROR1 or PTK7 ) over the chip’s capture surface. Regeneration of the capture surface can be carried out with 10mM glycine at pH1.7. This removes the captured antibody and allows the surface to be used for another interaction. The binding data can be fitted to 1:1 model inherent using standard techniques, e.g., using a model inherent to the ProteOn XPR36 ^TM analysis software. Alternatively, BLI methods are used to determine affinity using Octet BLI system (Sartorius). Unless otherwise stated, BLI was used to determine affinity of the PTK7 monomers, PTK7 mono-specific hFc fusions and the ROR1 x PTK7 all binding measurements disclosed herein. ROR1 or PTK7 ligand is attached to biosensors by standard amine coupling (ARG2 biosensors) or by affinity capture (for example using anti-human Fc capture with AHC biosensors, or anti-His capture using HIS1K biosensors). Sensors are dipped into test analyte and binding affinity calculated from the association and disassociation rates of analyte. Furthermore, the ROR1-specific antigen binding molecule is preferably capable of mediating killing of ROR1-expressing tumour cells or is capable of inhibiting cancer cell proliferation. The ROR1-specific antigen binding molecule may also be capable of being endocytosed upon binding to ROR1. In other embodiments, the ROR1-specific antigen binding molecule may not be endocytosed upon binding to ROR1. The ROR1-specific antigen binding molecule may comprise any of the sequences set out below, each of which is disclosed in WO 2019/122447, hereby incorporated by reference in its entirety. In preferred embodiments of the first and/or second aspect of the invention, the ROR1-specific antigen binding molecules comprises any one of the sequences set out below. B1 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPWLVQWYDGAGTVLTVN (SEQ ID NO: 113) D3 ASVNQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KRAKSFS LRIKDLTVADSATYYCKAQSGMAISTGSGHGYNWYDGAGTVLTVN (SEQ ID NO: 457) BA11 TRVDQSPSSLSASVGDRVTITCVLTDTSYPLYSTYWYRKNPGSSNKEQISISGRYSESVN KGTKSFTL TISSLQPEDSATYYCRAMSTNIWTGDGAGTKVEIK (SEQ ID NO: 95) E9 AKVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KRAKSFS LRIKDLTVADSATYYCKAQSGMAIDIGSGHGYNWYDGAGTVLTVN (SEQ ID NO: 458) B1G2 TRVDQSPSSLSASVGDRVTITCVLTGANYGLASTYWYRKNPGSSNQERISISGRYSESVN KRTMSFTL TISSLQPEDSATYYCRAYPWGAGAPWLVQWYDGAGTKVEIK (SEQ ID NO: 459) B1G1 TRVDQSPSSLSASVGDRVTITCVLTGANYGLASTYWYRKNPGSSNKEQISISGRYSESVN KGTKSFTL TISSLQPEDSATYYCRAYPWGAGAPWLVQWYDGAGTKVEIK (SEQ ID NO: 460) P3A1 V1 TRVDQSPSSLSASVGDRVTITCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFT LTISSLQPEDFATYYCKAREARHPWLRQWYDGAGTKVEIK (SEQ ID NO: 461) P3A1 G1 TRVDQSPSSLSASVGDRVTITCVLTDTSYGLYSTYWYRKNPGSSNKEQISISGRYSESVN KGTKSFTL TISSLQPEDSATYYCRAREARHPWLRQWYDGAGTKVEIK (SEQ ID NO: 114) P3A1 G2 TRVDQSPSSLSASVGDRVTITCVLTDTSYGLYSTYWYRKNPGTTDWERMSIGGRYSESVN KGAKSFT LTISSLQPEDSATYYCRAREARHPWLRQWYDGAGTKVEIK (SEQ ID NO: 462) D3 humanised ADV1 ASVNQSPSSLSASVGDRVTITCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYSESVN KGAKSFT LTISSLQPEDSATYYCKAQSGMAISTGSGHGYNWYDGAGTKVEIK (SEQ ID NO: 463) D3 humanised ADV2 TRVDQSPSSLSASVGDRVTITCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYSESVN KGAKSFT LTISSLQPEDSATYYCKAQSGMAISTGSGHGYNWYDGAGTKVEIK (SEQ ID NO: 464) D3 humanised ADV3 ASVNQSPSSASASVGDRLTITCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYSESVN KGAKSFT LTISSLQPEDSATYYCKAQSGMAISTGSGHGYNWYDGAGTKLEVK (SEQ ID NO: 465) B1 humanised V5 ASVDQSPSSLSASVGDRVTITCVVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFTL TISSLQPEDSATYYCKAYPWGAGAPWLVQWYDGAGTKVEIK (SEQ ID NO: 466) B1 humanised V7 ASVDQSPSSASASVGDRLTITCVVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFTL TISSLQPEDSATYYCKAYPWGAGAPWLVQWYDGAGTKLEVK (SEQ ID NO: 467) D3 humanised EL V1 ASVNQSPSSLSASVGDRVTITCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KRAKSFS LRIKDLTVADSATYYCKAQSGMAISTGSGHGYNWYDGAGTKVEIK (SEQ ID NO: 468) D3 humanised EL V2 ASVNQSPSSLSASVGDRVTITCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KRAKSFT LTISSLQPEDFATYYCKAQSGMAISTGSGHGYNWYDGAGTKVEIK (SEQ ID NO: 469) D3 humanised EL V3 ASVNQSPSSLSASVGDRVTITCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRFSGSGS KRAKSFT LTISSLQPEDFATYYCKAQSGMAISTGSGHGYNWYDGAGTKVEIK (SEQ ID NO: 470) D3 humanised EL V4 ASVNQSPSSLSASVGDRVTITCVLTDTSYGLYSTSWYQQKPGTTDWERMSIGGRYVESVN KRAKSFT LTISSLQPEDFATYYCKAQSGMAISTGSGHGYNWYDGAGTKVEIK (SEQ ID NO: 471) D3 humanised EL V5 ASVNQSPSSLSASVGDRVTITCVLTDTSYGLYSTSWYQQKPGTTDWERMSIGGRFSGSGS KRAKSFT LTISSLQPEDFATYYCKAQSGMAISTGSGHGYNWYDGAGTKVEIK (SEQ ID NO: 472) Any of the ROR1 binding molecules disclosed in WO 2019/122447 may be incorporated into any of the aspects of the invention disclosed herein as the ROR1 specific antigen binding molecule. Therefore, the ROR1 binding molecules disclosed in WO 2019/122447 may for example be fused to one or more biologically active proteins, such as hFc, optionally via a linker. Also disclosed herein is a binding molecule 2V which is disclosed in WO 2019/122447 but acts as a negative control VNAR from a naïve library with no known target. 2V TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAQSLAISTRSYWYDGAGTVLTVN (SEQ ID NO: 456) According to a third aspect, the invention provides a recombinant fusion protein comprising a bi- specific antigen binding molecule according to the first or the second aspects of the invention. Preferably, in the recombinant fusion protein of the third aspect, the ROR1 specific antigen binding molecule and/or the PTK7 specific antigen binding molecule is fused to one or more biologically active proteins. The specific antigen binding molecule may be fused to one or more biologically active proteins via one or more linker domains. Preferred linkers include but are not limited to [G4S]x, where x is 1, 2, 3, 4, 5, or 6. Particular preferred linkers are G4S (SEQ ID NO: 222), [G4S]3 (SEQ ID NO: 86) and [G4S]5 (SEQ ID NO: 87) _. Other preferred linkers include the sequences PGVQPSP (SEQ ID NO: 88), PGVQPSPGGGGS (SEQ ID NO: 89) and PGVQPAPGGGGS (SEQ ID NO: 90). These linkers may be particularly useful when recombinant fusion proteins are expressed in different expression systems that differ in glycosylation patterns, such as CHO and insect, and those that do not glycosylate expressed proteins (e.g. E. coli). Any recombinant fusion protein sequence disclosed herein comprising a [G ₄ S] ₃ linker may alternatively possess any other linker sequence disclosed herein. It will also be appreciated that the fusion proteins of the invention can be constructed in any order, i.e., with the ROR1-specific antigen binding molecule at the N-terminus, C-terminus, or at neither terminus (e.g. in the middle of a longer amino acid sequence). The PTK7-specific antigen binding molecule may be at the N-terminus, C-terminus, or at neither terminus (e.g. in the middle of a longer amino acid sequence). Preferred biologically active proteins include, but are not limited to an immunoglobulin, an immunoglobulin Fc region, a fragment of an immunoglobulin Fc region, an Fc heavy chain, a CH2 region, a CH3 region, an immunoglobulin Fab region, a Fab’, a Fv, a Fv-Fc, a single chain Fv (scFv), scFv-Fc, (scFv)2, a diabody, a triabody, a tetrabody, a bispecific t-cell engager, an intein, a VNAR domain, a single domain antibody (sdAb), a VH domain, or a scaffold protein (affibodies, centyrins, darpins etc.). A particularly preferred biologically active protein is an immunoglobulin Fc region. Other preferred fusion proteins include VNAR-VNAR and VNAR-VNAR-VNAR. In one embodiment, the at least one biologically active protein is an immunoglobulin Fc region. The recombinant fusion protein may comprise a ROR1 specific antigen binding molecule fused to an immunoglobulin Fc region or a fragment thereof. The immunoglobulin Fc region or fragment thereof may be fused to the ROR1 specific antigen binding molecule via a linker. The immunoglobulin Fc region or fragment thereof and/or the linker may be fused to the C-terminus of the ROR1 specific antigen binding molecule. Therefore, the recombinant fusion protein may comprise a sequence according to SEQ ID NO: 186, SEQ ID NO: 187, SEQ ID NO: 183, SEQ ID NO: 184, SEQ ID NO: 185 or SEQ ID NO: 223.. G3CP-hFc ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 186) G3CPG4-hFc TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIKGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQ GNVFSC SVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 187) 1H8-hFc ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSSVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQ GNVFSC SVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 183) 1H8 G4-hFc TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPSSVQWYDGAGTKVEIKGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQ GNVFSC SVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 184) 1H8 V15-hFc ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPSSVQWYDGQGTKLEVKGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 185) P3A1-hFc TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHT CPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVH NAKTKPR EEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLP PSRDELTK NQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQG NVFSCS VMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 223) The recombinant fusion protein may comprise a sequence according to SEQ ID NO: 186, SEQ ID NO: 187, SEQ ID NO: 183 or SEQ ID NO: 223. The recombinant fusion protein may comprise a sequence according to SEQ ID NO: 186, SEQ ID NO: 187 or SEQ ID NO: 183. In a further embodiment, the at least one biologically active protein is an immunoglobulin Fc region further modified to comprise an S to C mutation. The S to C mutation may be at position S239 (EU numbering). Therefore, the recombinant fusion protein may comprise a sequence according to SEQ ID NO: 178, SEQ ID NO: 179, SEQ ID NO: 180, SEQ ID NO: 181, or SEQ ID NO: 182 or SEQ ID NO: 224. G3CP-hFc(S239C) ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 178) G3CPG4-hFc(S239C) TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIKGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQ GNVFSC SVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 179) 1H8-hFc (S239C) ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSSVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQ GNVFSC SVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 180) 1H8 G4-hFc (S239C) TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPSSVQWYDGAGTKVEIKGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQ GNVFSC SVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 181) 1H8 V15-hFc (S239C) ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPSSVQWYDGQGTKLEVKGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 182) P3A1-hFc (S239C) TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHT CPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVH NAKTKPR EEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLP PSRDELTK NQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQG NVFSCS VMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 224) The recombinant fusion protein may comprise a sequence according to SEQ ID NO: 178, SEQ ID NO: 179, SEQ ID NO: 180 or SEQ ID NO: 224. The recombinant fusion protein may comprise a sequence according to SEQ ID NO: 178, SEQ ID NO: 179 or SEQ ID NO: 180. The S to C mutation may be at position S442 (EU numbering). Therefore, the recombinant fusion protein may comprise a sequence according to SEQ ID NO: 225, SEQ ID NO: 226, SEQ ID NO: 227, SEQ ID NO: 228, or SEQ ID NO: 229 or SEQ ID NO: 230.. G3CP-hFc (S442C) ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLCLSPGK (SEQ ID NO: 225) G3CPG4-hFc (S442C) TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIKGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQ GNVFSC SVMHEALHNHYTQKSLCLSPGK (SEQ ID NO: 226) 1H8-hFc (S442C) ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSSVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQ GNVFSC SVMHEALHNHYTQKSLCLSPGK (SEQ ID NO: 227) 1H8 G4-hFc (S442C) TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPSSVQWYDGAGTKVEIKGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQ GNVFSC SVMHEALHNHYTQKSLCLSPGK (SEQ ID NO: 228) 1H8 V15-hFc (S442C) ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPSSVQWYDGQGTKLEVKGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLCLSPGK (SEQ ID NO: 229) P3A1-hFc (S442C) TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHT CPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVH NAKTKPR EEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLP PSRDELTK NQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQG NVFSCS VMHEALHNHYTQKSLCLSPGK (SEQ ID NO: 230) The recombinant fusion protein may comprise a sequence according to SEQ ID NO: 225, SEQ ID NO: 226, SEQ ID NO: 227 or SEQ ID NO: 230. The recombinant fusion protein may comprise a sequence according to SEQ ID NO: 225, SEQ ID NO: 226 or SEQ ID NO: 227. The S to C mutation may be at both position S239 and S442 (EU numbering). Therefore, the recombinant fusion protein may comprise a sequence according to SEQ ID NO: 231, SEQ ID NO: 232, SEQ ID NO: 233, SEQ ID NO: 234, or SEQ ID NO: 235 or SEQ ID NO: 236. G3CP-hFc (S239C & S442C) ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLCLSPGK (SEQ ID NO: 231) G3CPG4-hFc (S239C & S442C) TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIKGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQ GNVFSC SVMHEALHNHYTQKSLCLSPGK (SEQ ID NO: 232) 1H8-hFc (S239C & S442C) ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSSVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQ GNVFSC SVMHEALHNHYTQKSLCLSPGK (SEQ ID NO: 233) 1H8 G4-hFc (S239C & S442C) TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPSSVQWYDGAGTKVEIKGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQ GNVFSC SVMHEALHNHYTQKSLCLSPGK (SEQ ID NO: 234) 1H8 V15-hFc (S239C & S442C) ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPSSVQWYDGQGTKLEVKGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLCLSPGK (SEQ ID NO: 235) P3A1-hFc (S239C & S442C) TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHT CPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVH NAKTKPR EEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLP PSRDELTK NQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQG NVFSCS VMHEALHNHYTQKSLCLSPGK (SEQ ID NO: 236) The recombinant fusion protein may comprise a sequence according to SEQ ID NO: 231, SEQ ID NO: 232, SEQ ID NO: 233 or SEQ ID NO: 236. The recombinant fusion protein may comprise a sequence according to SEQ ID NO: 231, SEQ ID NO: 232 or SEQ ID NO: 233. The recombinant fusion protein may comprise an PTK7 specific antigen binding molecule fused to an immunoglobulin Fc region or a fragment thereof. The immunoglobulin Fc region or fragment thereof may be fused to the PTK7 specific antigen binding molecule via a linker. The immunoglobulin Fc region or fragment thereof and/or the linker may be fused to the C-terminus of the PTK7 specific antigen binding molecule. The PTK7 specific antigen binding molecule fused to an immunoglobulin Fc region may therefore comprise a sequence according to any one of SEQ ID Nos 473 to 484. The PTK7 specific antigen binding molecule fused to an immunoglobulin Fc region may therefore comprise a sequence according to any one of SEQ ID Nos 473 to 475. The PTK7 specific antigen binding molecule fused to an immunoglobulin Fc region may therefore comprise a sequence according to any one of SEQ ID Nos 476 to 478. The PTK7 specific antigen binding molecule fused to an immunoglobulin Fc region may therefore comprise a sequence according to any one of SEQ ID Nos 479 to 481. The PTK7 specific antigen binding molecule fused to an immunoglobulin Fc region may therefore comprise a sequence according to any one of SEQ ID Nos 482 to 484. P2A7 hFc (SEQ ID NO: 473) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHTC PPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHN AKTKPRE EQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPP SRDELTKN QVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGN VFSCSV MHEALHNHYTQKSLSLSPGK 4D2 hFc (SEQ ID NO: 474) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSGGGGSGGGGSEPK SSDKT HTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLSLSPGK E02 hFc (SEQ ID NO: 475) ASVNQTPRTATKETGESLTINCVVTGAGYALAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAFLPPRVWHGVKMQHWYDGAGTVLTVNGGGGSGGGGSGGGGSEP KSSD KTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDG VEVHNAK TKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQV YTLPPSRD ELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSR WQQGNVF SCSVMHEALHNHYTQKSLSLSPGK P2A7 hFc S239C (SEQ ID NO: 476) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHTC PPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHN AKTKPRE EQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPP SRDELTKN QVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGN VFSCSV MHEALHNHYTQKSLSLSPGK 4D2 hFc S239C (SEQ ID NO: 477) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSGGGGSGGGGSEPK SSDKT HTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLSLSPGK E02 hFc S239C (SEQ ID NO: 478) ASVNQTPRTATKETGESLTINCVVTGAGYALAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAFLPPRVWHGVKMQHWYDGAGTVLTVNGGGGSGGGGSGGGGSEP KSSD KTHTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDG VEVHNAK TKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQV YTLPPSRD ELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSR WQQGNVF SCSVMHEALHNHYTQKSLSLSPGK P2A7 hFc S442C (SEQ ID NO: 479) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHTC PPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHN AKTKPRE EQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPP SRDELTKN QVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGN VFSCSV MHEALHNHYTQKSLCLSPGK 4D2 hFc S442C (SEQ ID NO: 480) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSGGGGSGGGGSEPK SSDKT HTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLCLSPGK E02 hFc S442C (SEQ ID NO: 481) ASVNQTPRTATKETGESLTINCVVTGAGYALAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAFLPPRVWHGVKMQHWYDGAGTVLTVNGGGGSGGGGSGGGGSEP KSSD KTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDG VEVHNAK TKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQV YTLPPSRD ELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSR WQQGNVF SCSVMHEALHNHYTQKSLCLSPGK P2A7 hFc (S239C+S442C) (SEQ ID NO: 482) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHTC PPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHN AKTKPRE EQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPP SRDELTKN QVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGN VFSCSV MHEALHNHYTQKSLCLSPGK 4D2 hFc (S239C+S442C) (SEQ ID NO: 483) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSGGGGSGGGGSEPK SSDKT HTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLCLSPGK E02 hFc (S239C+S442C) (SEQ ID NO: 484) ASVNQTPRTATKETGESLTINCVVTGAGYALAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAFLPPRVWHGVKMQHWYDGAGTVLTVNGGGGSGGGGSGGGGSEP KSSD KTHTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDG VEVHNAK TKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQV YTLPPSRD ELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSR WQQGNVF SCSVMHEALHNHYTQKSLCLSPGK SEQ ID Nos 178 to 187, 223 to 236, and 473 to 484 each comprise a (G4S)3 linker. Also, explicitly contemplated herein are the corresponding sequences wherein the (G ₄ S) ₃ linker is replaced with a (G4S)1 linker. For instance, the recombinant fusion protein may comprise one or more of the following SEQ ID Nos 408 to 431 and 485 to 496. G3CP G ₄ S-hFc ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPC PAPELL GGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLSLSPGK (SEQ ID NO: 408) G3CPG4 G4S-hFc TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIKGGGGSEPKSSDKTHTCPPC PAPELL GGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLSLSPGK (SEQ ID NO: 409) 1H8 G4S-hFc ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSSVQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPC PAPELL GGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLSLSPGK (SEQ ID NO: 410) 1H8 G4 G4S-hFc TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPSSVQWYDGAGTKVEIKGGGGSEPKSSDKTHTCPPC PAPELL GGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLSLSPGK (SEQ ID NO: 411) 1H8 V15 G4S-hFc ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPSSVQWYDGQGTKLEVKGGGGSEPKSSDKTHTCPPC PAPELL GGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLSLSPGK (SEQ ID NO: 412) P3A1 G4S-hFc TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPCP APELLG GPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQY NSTYRVV SVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQV SLTCLVKG FYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEA LHNHYT QKSLSLSPGK (SEQ ID NO: 413) G3CP G4S-hFc(S239C) ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLSLSPGK (SEQ ID NO: 414) G3CPG4 G4S-hFc(S239C) TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIKGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLSLSPGK (SEQ ID NO: 415) 1H8 G4S-hFc (S239C) ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSSVQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLSLSPGK (SEQ ID NO: 416) 1H8 G4 G ₄ S-hFc (S239C) TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPSSVQWYDGAGTKVEIKGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLSLSPGK (SEQ ID NO: 417) 1H8 V15 G4S-hFc (S239C) ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPSSVQWYDGQGTKLEVKGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLSLSPGK (SEQ ID NO: 418) P3A1 G4S-hFc (S239C) TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPCP APELLG GPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQY NSTYRVV SVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQV SLTCLVKG FYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEA LHNHYT QKSLSLSPGK (SEQ ID NO: 419) G3CP G4S-hFc (S442C) ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPC PAPELL GGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK (SEQ ID NO: 420) G3CPG4 G4S-hFc (S442C) TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIKGGGGSEPKSSDKTHTCPPC PAPELL GGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK (SEQ ID NO: 421) 1H8 G4S-hFc (S442C) ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSSVQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPC PAPELL GGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK (SEQ ID NO: 422) 1H8 G4 G4S-hFc (S442C) TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPSSVQWYDGAGTKVEIKGGGGSEPKSSDKTHTCPPC PAPELL GGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK (SEQ ID NO: 423) 1H8 V15 G4S-hFc (S442C) ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPSSVQWYDGQGTKLEVKGGGGSEPKSSDKTHTCPPC PAPELL GGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK (SEQ ID NO: 424) P3A1 G ₄ S-hFc (S442C) TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPCP APELLG GPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQY NSTYRVV SVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQV SLTCLVKG FYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEA LHNHYT QKSLCLSPGK (SEQ ID NO: 425) G3CP G4S-hFc (S239C & S442C) ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK (SEQ ID NO: 426) G3CPG4 G4S-hFc (S239C & S442C) TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIKGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK (SEQ ID NO: 427) 1H8 G ₄ S-hFc (S239C & S442C) ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSSVQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK (SEQ ID NO: 428) 1H8 G4 G4S-hFc (S239C & S442C) TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPSSVQWYDGAGTKVEIKGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK (SEQ ID NO: 429) 1H8 V15 G4S-hFc (S239C & S442C) ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPSSVQWYDGQGTKLEVKGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK (SEQ ID NO: 430) P3A1 G4S-hFc (S239C & S442C) TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPCP APELLG GPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQY NSTYRVV SVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQV SLTCLVKG FYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEA LHNHYT QKSLCLSPGK (SEQ ID NO: 431) P2A7 G4S-hFc (SEQ ID NO: 485) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPCP APELLGG PSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYN STYRVVS VLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVS LTCLVKGF YPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEAL HNHYTQ KSLSLSPGK 4D2 G4S-hFc (SEQ ID NO: 486) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSEPKSSDKTHTCPP CPAPEL LGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREE QYNSTYR VVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKN QVSLTCLV KGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMH EALHNH YTQKSLSLSPGK E02 G4S-hFc (SEQ ID NO: 487) ASVNQTPRTATKETGESLTINCVVTGAGYALAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAFLPPRVWHGVKMQHWYDGAGTVLTVNGGGGSEPKSSDKTHTCP PCPAPE LLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPRE EQYNSTY RVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTK NQVSLTCL VKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVM HEALHN HYTQKSLSLSPGK P2A7 G4S-hFc S239C (SEQ ID NO: 488) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPCP APELLGG PCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYN STYRVVS VLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVS LTCLVKGF YPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEAL HNHYTQ KSLSLSPGK 4D2 G4S-hFc S239C (SEQ ID NO: 489) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSEPKSSDKTHTCPP CPAPEL LGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREE QYNSTYR VVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKN QVSLTCLV KGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMH EALHNH YTQKSLSLSPGK E02 G4S-hFc S239C (SEQ ID NO: 490) ASVNQTPRTATKETGESLTINCVVTGAGYALAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAFLPPRVWHGVKMQHWYDGAGTVLTVNGGGGSEPKSSDKTHTCP PCPAPE LLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPRE EQYNSTY RVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTK NQVSLTCL VKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVM HEALHN HYTQKSLSLSPGK P2A7 G4S-hFc S442C (SEQ ID NO: 491) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPCP APELLGG PSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYN STYRVVS VLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVS LTCLVKGF YPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEAL HNHYTQ KSLCLSPGK 4D2 G4S-hFc S442C (SEQ ID NO: 492) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSEPKSSDKTHTCPP CPAPEL LGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREE QYNSTYR VVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKN QVSLTCLV KGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMH EALHNH YTQKSLCLSPGK E02 G4S-hFc S442C (SEQ ID NO: 493) ASVNQTPRTATKETGESLTINCVVTGAGYALAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAFLPPRVWHGVKMQHWYDGAGTVLTVNGGGGSEPKSSDKTHTCP PCPAPE LLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPRE EQYNSTY RVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTK NQVSLTCL VKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVM HEALHN HYTQKSLCLSPGK P2A7 G4S-hFc (S239C+S442C) (SEQ ID NO: 494) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPCP APELLGG PCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYN STYRVVS VLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVS LTCLVKGF YPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEAL HNHYTQ KSLCLSPGK 4D2 G4S-hFc (S239C+S442C) (SEQ ID NO: 495) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSEPKSSDKTHTCPP CPAPEL LGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREE QYNSTYR VVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKN QVSLTCLV KGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMH EALHNH YTQKSLCLSPGK E02 G4S-hFc (S239C+S442C) (SEQ ID NO: 496) ASVNQTPRTATKETGESLTINCVVTGAGYALAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAFLPPRVWHGVKMQHWYDGAGTVLTVNGGGGSEPKSSDKTHTCP PCPAPE LLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPRE EQYNSTY RVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTK NQVSLTCL VKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVM HEALHN HYTQKSLCLSPGK In one embodiment, the at least one biologically active protein is a fragment of an immunoglobulin Fc region selected from the group consisting of an Fc heavy chain, a CH2 region and a CH3 region. In one embodiment, the fragment of an immunoglobulin Fc region is an Fc heavy chain. In one embodiment, one or more residues of fusion protein comprises one or more amino acid substitution suitable for conjugation. The one or more residues suitable for conjugation may be residues of the fragment of the immunoglobulin Fc region. Any part of the fusion protein of the invention may be engineered to enable conjugation. In a preferred example, where an immunoglobulin Fc region is used, it may be engineered to include a cysteine residue as a conjugation site. Preferred introduced cysteine residues include, but are not limited to S252C and S473C (Kabat numbering), which correspond to S239C and S442C in EU numbering, respectively. In some embodiments, any of the fusion proteins disclosed herein may comprise the S239C point mutation. In some embodiments, any of the fusion proteins disclosed herein may comprise the S442C point mutation. In some embodiments, any of the fusion proteins disclosed herein may comprise both S239C and S442C point mutations. It is explicitly contemplated herein that sequence of any of the fusion proteins disclosed herein may be modified to include an S239C and/or S442C point mutation. In accordance with the third aspect, recombinant fusions comprising multiple VNAR domains are provided. Accordingly, the recombinant fusions of the invention may be dimers, trimers or higher order multimers of VNARs. In such recombinant fusions, the specificity of each VNAR may be the same or different. Recombinant fusions of the invention include, but are not limited to, bi-specific or tri-specific molecules in which each VNAR domain binds to a different antigen, or to different epitopes on a single antigen (bi-paratopic binders). The term “bi-paratopic” as used herein is intended to encompass molecules that bind to multiple epitopes on a given antigen. Molecules that bind three or more eptiopes on a given antigen are also contemplated herein and where the term “bi-paratopic” is used, it should be understood that the potential for tri-paratopic or multi-paratopic molecules is also encompassed. Also in accordance with the third aspect, recombinant fusions are provided which include a ROR1- specific antigen binding molecule of the first aspect and a humanised VNAR domain. Humanised VNAR domains may be referred to as soloMERs and include but are not limited to the VNAR BA11, which is a humanised VNAR that binds with high affinity to human serum albumin. Examples of bi-paratopic and multivalent fusion proteins include, but are not limited to:

^ B1-G3CP ^ G3CP-BA11 ^ BA11-G3CP ^ 1H8-BA11 ^ BA11-1H8 ^ G3CP V15-BA11 ^ G3CP G4-BA11 ^ B1-G3CP Cys ^ G3CP-BA11 Cys ^ BA11-G3CP Cys ^ 1H8-BA11 Cys ^ BA11-1H8 Cys ^ G3CP V15-BA11 Cys ^ G3CP G4-BA11 Cys ^ P3A1G1AE3-(L2)-G3CPG4 ^ G3CPG4 (L2)--P3A1G1AE3 ^ P3A1G1AE3-(L2)-G3CPG4 Cys ^ G3CPG4-(L2)-P3A1G1AE3 Cys ^ P3A1-(L2)-BA11-(L2)-G3CP ^ P3A1-(L2)-G3CP-(L2)-BA11 ^ BA11-(L2)-G3CP-(L2)-P3A1 ^ BA11-(L2)-P3A1-(L2)-G3CP ^ P3A1-(L2)-BA11-(L2)-1H8 ^ BA11-(L2)-P3A1-(L2)-1H8 ^ P3A1-(L2)-BA11-(L2)-G3CP Cys ^ P3A1-(L2)-G3CP-(L2)-BA11 Cys ^ BA11-(L2)-G3CP-(L2)-P3A1 Cys ^ BA11-(L2)-P3A1-(L2)-G3CP Cys ^ P3A1-(L2)-BA11-(L2)-1H8 Cys ^ BA11-(L ₂ )-1P3A1-(L ₂ )-1H8 Cys Wherein: G3CP is ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVN (SEQ ID NO: 50) 1H8 is ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSSVQWYDGAGTVLTVN (SEQ ID NO: 61) G3CP G4 is TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIK (SEQ ID NO: 71) G3CP V15 is ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPYNVQWYDGQGTKLEVK (SEQ ID NO: 72) BA11 is TRVDQSPSSLSASVGDRVTITCVLTDTSYPLYSTYWYRKNPGSSNKEQISISGRYSESVN KGTKSFTL TISSLQPEDSATYYCRAMSTNIWTGDGAGTKVEIK (SEQ ID NO: 95) P3A1 G1 AE3 is TRVDQSPSSLSASVGDRVTITCVLTGTRYGLYSTYWYRKNPGSSDEERISISGRYSESVN KGTKSFTL TISSLQPEDSATYYCRAREARHPWLRQWYDGAGTKVEIK (SEQ ID NO: 77) and where no linker is defined (-) corresponds to the linker Wobbe-G5S, which in turn is PGVQPSPGGGGGS (SEQ ID NO: 96) -(L ₂ )- corresponds to the linker Wobbe-G ₄ S-GM, which in turn is PGVQPAPGGGGS (SEQ ID NO: 90) Cys – corresponds to a Cys containing C-terminal tag – for example QACKAHHHHHHGAEFEQKLISEEDL (SEQ ID NO: 97) Recombinant bi-paratopic fusion protein dimers can also be made by fusing any recombinant fusion protein disclosed herein, in particular ROR1 specific antigen binding molecules disclosed herein, onto one arm of an Fc fusion and by fusing a protein tyrosine kinase 7 (PTK7) specific antigen binding molecule onto the other. In certain embodiments, the specific binding molecules or recombinant fusions of the invention may be expressed with N- or C-terminal tags to assist with purification. Examples include but are not limited to His6 and/or Myc. In addition, the N- or C-terminal tag may be further engineered to include additional cysteine residues to serve as conjugation points. It will therefore be appreciated that reference to specific binding molecules or recombinant fusions in all aspects of the invention is also intended to encompass such molecules with a variety of N- or C-terminal tags, which tags may also include additional cysteines for conjugation. Additional recombinant fusions are listed below. It will be appreciated that not every combination of linker and VNAR or fusion partner is listed below. However, all such combinations are expressly encompassed by the present invention. Monovalent-BA11 fusions Dimeric biparatopic BA11 fusions BA11-G3CP G3CP-P3A1G1 AE3-BA11 G3CP-BA11 P3A1G1 AE3-G3CP-BA11 BA11-G3CPG4 G3CP-BA11-P3A1G1 AE3 G3CPG4-BA1 P3A1G1 AE3-BA11-G3CP P3A1G1 AE3-BA11 G3CPG4-P3A1G1 AE3-BA11 BA11-P3A1G1 AE3 P3A1G1 AE3-G3CPG4-BA11 G3CPG4-BA11-P3A1G1 AE3 Divalent-BA11 fusions P3A1G1 AE3-BA11-G3CPG4 P3A1G1 AE3-P3A1G1 AE3-BA11 B1G4-P3A1G1 AE3-BA11 BA11-P3A1G1 AE3-P3A1G1 AE3 P3A1G1 AE3-B1G4-BA11 P3A1G1 AE3-BA11-P3A1G1 AE3 B1G4-BA11-P3A1G1 AE3 G3CP-G3CP-BA11 P3A1G1 AE3-BA11-B1G4 G3CP-BA11-G3CP BA11-G3CP-G3CP G3CPG4-G3CPG4-BA11 G3CPG4-BA11-G3CPG4 BA11-G3CPG4-G3CPG4 B1G4-B1G4-BA11 B1G4-BA11-B1G4 BA11-B1G4-B1G4 Biparatopic Dimers G3CP-P3A1G1 AE3 P3A1G1 AE3-G3CP G3CPG4-P3A1G1 AE3 P3A1G1 AE3-G3CPG4 Linkers between VNAR domains are preferentially, but not limited to (G ₄ S) ₅ (SEQ ID NO: 87), (G ₄ S) ₃ (SEQ ID NO: 86), (G4S)7 (SEQ ID NO: 116), PGVQPSPGGGGS (SEQ ID NO: 89) (Wobbe-G4S), PGVQPAPGGGGS (SEQ ID NO: 90) (Wobbe-G4S GM), PGVQPCPGGGGGS (SEQ ID NO: 177) (WobbeCys-G5S), PGVQPCPGGGGS (SEQ ID NO: 432) (WobbeCys-G4S) and wherein different combinations of different linkers can be combined within the same construct. The WobbeCys-G ₄ S sequence also contains a single cysteine residue to facilitate site-selective bioconjugation of payloads to the proteins, in this linker, using thiol mediated chemical coupling strategies. The use of this linker sequence for bioconjugation is advantageous as reoxidation and capping of the reduced cysteine is minimal, leading to high yielding conversion of the protein to the corresponding conjugate in bioconjugation reactions. In a preferred embodiment, bi-paratopic fusion protein can also be made by fusing any of the ROR1 specific antigen binding molecules disclosed herein to any of the protein tyrosine kinase 7 (PTK7) specific antigen binding molecule disclosed herein. The bi-paratopic-fusion protein may have the “beads-on-a-string” format. The bi-paratopic fusion protein may comprise any of the linkers disclosed herein. Preferably, the bi-paratopic fusion protein may comprise the WobbeCys-G4S linker disclosed herein. The bi-paratopic fusion protein may have a sequence selected from the group consisting of SEQ ID NO: 497 to 499. P3A1-WbCys-P2A7 (SEQ ID NO: 497) TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVNPGVQPCPGGGGSTRVDQTPR TATKET GESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVNKGAKSFSLRIKDLT VADSATYY CKAAYIERNGFLTWYDGAGTVLTVN P2A7-WbCys-G3CP (SEQ ID NO: 498) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNPGVQPCPGGGGSASVNQTPR TATKETG ESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVNKRTMSFSLRIKDLTV ADSATYYC KAYPWGAGAPYNVQWYDGAGTVLTVN P2A7-WbCys-P3A1 (SEQ ID NO: 499) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNPGVQPCPGGGGSTRVDQTPR TATKETG ESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVNKGAKSFSLRIKDLTV ADSATYYC KAREARHPWLRQWYDGAGTVLTVN Additional C-terminal (or N-terminal) tag sequences may or may not be present. C-terminal tags include, but are not limited to, tags that contain poly-Histidine sequences to facilitate purification (such as His6), contain c-Myc sequences (such as EQKLISEEDL (SEQ ID NO: 112)) to enable detection and / or contain Cysteine residues to enable labelling and bioconjugation using thiol reactive payloads and probes and combinations thereof. Preferential C-terminal tags include but are not limited to: QASGAHHHHHHGAEFEQKLISEEDL (SEQ ID NO: 98) QACGAHHHHHHGAEFEQKLISEEDL (SEQ ID NO: 99) QACKAHHHHHHGAEFEQKLISEEDL (SEQ ID NO: 97) AAAHHHHHHGAEFEQKLISEEDL (SEQ ID NO: 100) ACAHHHHHHGAEFEQKLISEEDL (SEQ ID NO: 101) QASGAHHHHHH (SEQ ID NO: 102) QACGAHHHHHH (SEQ ID NO: 103) QACKAHHHHHH (SEQ ID NO: 104) AAAHHHHHH (SEQ ID NO: 105) ACAHHHHHH (SEQ ID NO: 106) QASGA (SEQ ID NO: 107) QACGA (SEQ ID NO: 108) QACKA (SEQ ID NO: 109) ACA (SEQ ID NO: 110) SAPSA (SEQ ID NO: 111) Wherein: G3CP is ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVN (SEQ ID NO: 50) G3CP G4 is TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIK (SEQ ID NO: 71) BA11 is TRVDQSPSSLSASVGDRVTITCVLTDTSYPLYSTYWYRKNPGSSNKEQISISGRYSESVN KGTKSFTL TISSLQPEDSATYYCRAMSTNIWTGDGAGTKVEIK (SEQ ID NO: 95) P3A1 G1 AE3 is TRVDQSPSSLSASVGDRVTITCVLTGTRYGLYSTYWYRKNPGSSDEERISISGRYSESVN KGTKSFTL TISSLQPEDSATYYCRAREARHPWLRQWYDGAGTKVEIK (SEQ ID NO: 77) B1G4 is TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPWLVQWY DGAGTKVEIK (SEQ ID NO: 51) All combinations of VNAR and linker are expressly encompassed herein. Humanised derivatives of the VNARs are also encompassed herein. Any recombinant fusion protein disclosed herein which does refer to the presence an PTK7 specific binding molecule can be modified to include an PTK7 specific binding molecule. Any PTK7 specific binding molecules disclosed herein are explicitly contemplated as combined with any recombinant fusion protein disclosed herein which does refer to the presence an PTK7 specific binding molecule in any configuration. Also in accordance with the third aspect, recombinant fusions are provided which include a ROR1- specific antigen binding molecule and a recombinant toxin. Examples of recombinant toxins include but are not limited to Pseudomonas exotoxin PE38 and diphtheria toxin. Also in accordance with the third aspect, recombinant fusions are provided which include a ROR1- specific antigen binding molecule and a recombinant CD3 binding protein. Examples of recombinant ROR1 and CD3 binding agents include but are not limited to: B1G4–[WGM]–CD3 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPWLVQWYDGAGTKVEIKPGVQPAPGGGGSDIKLQQS GAELAR PGASVKMSCKTSGYTFTRYTMHWVKQRPGQGLEWIGYINPSRGYTNYNQKFKDKATLTTD KSSSTA YMQLSSLTSEDSAVYYCARYYDDHYCLDYWGQGTTLTVSSGGGGSGGGGSGGGGSDIQLT QSPAI MSASPGEKVTMTCRASSSVSYMNWYQQKSGTSPKRWIYDTSKVASGVPYRFSGSGSGTSY SLTISS MEAEDAATYYCQQWSSNPLTFGAGTKLELKSHHHHHH (SEQ ID NO: 117) G3CP–[WGM]–CD3 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNPGVQPAPGGGGSDIKLQQS GAELAR PGASVKMSCKTSGYTFTRYTMHWVKQRPGQGLEWIGYINPSRGYTNYNQKFKDKATLTTD KSSSTA YMQLSSLTSEDSAVYYCARYYDDHYCLDYWGQGTTLTVSSGGGGSGGGGSGGGGSDIQLT QSPAI MSASPGEKVTMTCRASSSVSYMNWYQQKSGTSPKRWIYDTSKVASGVPYRFSGSGSGTSY SLTISS MEAEDAATYYCQQWSSNPLTFGAGTKLELKSHHHHHH (SEQ ID NO: 118) G3CPG4–[WGM]-CD3 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIKPGVQPAPGGGGSDIKLQQS GAELAR PGASVKMSCKTSGYTFTRYTMHWVKQRPGQGLEWIGYINPSRGYTNYNQKFKDKATLTTD KSSSTA YMQLSSLTSEDSAVYYCARYYDDHYCLDYWGQGTTLTVSSGGGGSGGGGSGGGGSDIQLT QSPAI MSASPGEKVTMTCRASSSVSYMNWYQQKSGTSPKRWIYDTSKVASGVPYRFSGSGSGTSY SLTISS MEAEDAATYYCQQWSSNPLTFGAGTKLELKSHHHHHH (SEQ ID NO: 119) P3A1G1AE3–[WGM]–CD3 TRVDQSPSSLSASVGDRVTITCVLTGTRYGLYSTYWYRKNPGSSDEERISISGRYSESVN KGTKSFTL TISSLQPEDSATYYCRAREARHPWLRQWYDGAGTKVEIKPGVQPAPGGGGSDIKLQQSGA ELARPG ASVKMSCKTSGYTFTRYTMHWVKQRPGQGLEWIGYINPSRGYTNYNQKFKDKATLTTDKS SSTAYM QLSSLTSEDSAVYYCARYYDDHYCLDYWGQGTTLTVSSGGGGSGGGGSGGGGSDIQLTQS PAIMSA SPGEKVTMTCRASSSVSYMNWYQQKSGTSPKRWIYDTSKVASGVPYRFSGSGSGTSYSLT ISSMEA EDAATYYCQQWSSNPLTFGAGTKLELKSHHHHHH (SEQ ID NO: 120) B1G4–[WGM]–BA11-[G4S]-CD3 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPWLVQWYDGAGTKVEIKPGVQPAPGGGGSTRVDQSP SSLSAS VGDRVTITCVLTDTSYPLYSTYWYRKNPGSSNKEQISISGRYSESVNKGTKSFTLTISSL QPEDSATYY CRAMSTNIWTGDGAGTKVEIKGGGGSDIKLQQSGAELARPGASVKMSCKTSGYTFTRYTM HWVKQR PGQGLEWIGYINPSRGYTNYNQKFKDKATLTTDKSSSTAYMQLSSLTSEDSAVYYCARYY DDHYCLD YWGQGTTLTVSSGGGGSGGGGSGGGGSDIQLTQSPAIMSASPGEKVTMTCRASSSVSYMN WYQQ KSGTSPKRWIYDTSKVASGVPYRFSGSGSGTSYSLTISSMEAEDAATYYCQQWSSNPLTF GAGTKLE LKSHHHHHH (SEQ ID NO: 121) G3CP–[WGM]–BA11-[G4S]-CD3 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNPGVQPAPGGGGSTRVDQSP SSLSA SVGDRVTITCVLTDTSYPLYSTYWYRKNPGSSNKEQISISGRYSESVNKGTKSFTLTISS LQPEDSATY YCRAMSTNIWTGDGAGTKVEIKGGGGSDIKLQQSGAELARPGASVKMSCKTSGYTFTRYT MHWVKQ RPGQGLEWIGYINPSRGYTNYNQKFKDKATLTTDKSSSTAYMQLSSLTSEDSAVYYCARY YDDHYCL DYWGQGTTLTVSSGGGGSGGGGSGGGGSDIQLTQSPAIMSASPGEKVTMTCRASSSVSYM NWYQ QKSGTSPKRWIYDTSKVASGVPYRFSGSGSGTSYSLTISSMEAEDAATYYCQQWSSNPLT FGAGTKL ELKSHHHHHH (SEQ ID NO: 122) G3CPG4–[WGM]–BA11-[G4S]-CD3 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIKPGVQPAPGGGGSTRVDQSP SSLSAS VGDRVTITCVLTDTSYPLYSTYWYRKNPGSSNKEQISISGRYSESVNKGTKSFTLTISSL QPEDSATYY CRAMSTNIWTGDGAGTKVEIKGGGGSDIKLQQSGAELARPGASVKMSCKTSGYTFTRYTM HWVKQR PGQGLEWIGYINPSRGYTNYNQKFKDKATLTTDKSSSTAYMQLSSLTSEDSAVYYCARYY DDHYCLD YWGQGTTLTVSSGGGGSGGGGSGGGGSDIQLTQSPAIMSASPGEKVTMTCRASSSVSYMN WYQQ KSGTSPKRWIYDTSKVASGVPYRFSGSGSGTSYSLTISSMEAEDAATYYCQQWSSNPLTF GAGTKLE LKSHHHHHH (SEQ ID NO: 123) P3A1G1AE3–[WGM]–BA11-[G4S]-CD3 TRVDQSPSSLSASVGDRVTITCVLTGTRYGLYSTYWYRKNPGSSDEERISISGRYSESVN KGTKSFTL TISSLQPEDSATYYCRAREARHPWLRQWYDGAGTKVEIKPGVQPAPGGGGSTRVDQSPSS LSASVG DRVTITCVLTDTSYPLYSTYWYRKNPGSSNKEQISISGRYSESVNKGTKSFTLTISSLQP EDSATYYCR AMSTNIWTGDGAGTKVEIKGGGGSDIKLQQSGAELARPGASVKMSCKTSGYTFTRYTMHW VKQRPG QGLEWIGYINPSRGYTNYNQKFKDKATLTTDKSSSTAYMQLSSLTSEDSAVYYCARYYDD HYCLDYW GQGTTLTVSSGGGGSGGGGSGGGGSDIQLTQSPAIMSASPGEKVTMTCRASSSVSYMNWY QQKSG TSPKRWIYDTSKVASGVPYRFSGSGSGTSYSLTISSMEAEDAATYYCQQWSSNPLTFGAG TKLELKS HHHHHH (SEQ ID NO: 124) P3A1–[WGM]–G3CP-[G4S]-CD3 TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVNPGVQPAPGGGGSASVNQTPR TATKET GESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVNKRTMSFSLRIKDLT VADSATYY CKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSDIKLQQSGAELARPGASVKMSCKTSGYT FTRYT MHWVKQRPGQGLEWIGYINPSRGYTNYNQKFKDKATLTTDKSSSTAYMQLSSLTSEDSAV YYCARY YDDHYCLDYWGQGTTLTVSSGGGGSGGGGSGGGGSDIQLTQSPAIMSASPGEKVTMTCRA SSSVS YMNWYQQKSGTSPKRWIYDTSKVASGVPYRFSGSGSGTSYSLTISSMEAEDAATYYCQQW SSNPLT FGAGTKLELKSHHHHHH (SEQ ID NO: 125) P3A1–[WGM]–G3CPG4-[G4S]-CD3 TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVNPGVQPAPGGGGSTRVDQSPS SLSASV GDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVNKGTMSFTLTISSLQ PEDSATYYC RAYPWGAGAPYNVQWYDGAGTKVEIKGGGGSDIKLQQSGAELARPGASVKMSCKTSGYTF TRYTM HWVKQRPGQGLEWIGYINPSRGYTNYNQKFKDKATLTTDKSSSTAYMQLSSLTSEDSAVY YCARYYD DHYCLDYWGQGTTLTVSSGGGGSGGGGSGGGGSDIQLTQSPAIMSASPGEKVTMTCRASS SVSYM NWYQQKSGTSPKRWIYDTSKVASGVPYRFSGSGSGTSYSLTISSMEAEDAATYYCQQWSS NPLTFG AGTKLELKSHHHHHH (SEQ ID NO: 126) P3A1G1AE3–[WGM]–G3CP-[G4S]-CD3 TRVDQSPSSLSASVGDRVTITCVLTGTRYGLYSTYWYRKNPGSSDEERISISGRYSESVN KGTKSFTL TISSLQPEDSATYYCRAREARHPWLRQWYDGAGTKVEIKPGVQPAPGGGGSASVNQTPRT ATKETG ESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVNKRTMSFSLRIKDLTV ADSATYYC KAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSDIKLQQSGAELARPGASVKMSCKTSGYTF TRYTM HWVKQRPGQGLEWIGYINPSRGYTNYNQKFKDKATLTTDKSSSTAYMQLSSLTSEDSAVY YCARYYD DHYCLDYWGQGTTLTVSSGGGGSGGGGSGGGGSDIQLTQSPAIMSASPGEKVTMTCRASS SVSYM NWYQQKSGTSPKRWIYDTSKVASGVPYRFSGSGSGTSYSLTISSMEAEDAATYYCQQWSS NPLTFG AGTKLELKSHHHHHH (SEQ ID NO: 127) P3A1G1AE3–[WGM]–G3CPG4-[G4S]-CD3 TRVDQSPSSLSASVGDRVTITCVLTGTRYGLYSTYWYRKNPGSSDEERISISGRYSESVN KGTKSFTL TISSLQPEDSATYYCRAREARHPWLRQWYDGAGTKVEIKPGVQPAPGGGGSTRVDQSPSS LSASVG DRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVNKGTMSFTLTISSLQP EDSATYYCR AYPWGAGAPYNVQWYDGAGTKVEIKGGGGSDIKLQQSGAELARPGASVKMSCKTSGYTFT RYTMH WVKQRPGQGLEWIGYINPSRGYTNYNQKFKDKATLTTDKSSSTAYMQLSSLTSEDSAVYY CARYYDD HYCLDYWGQGTTLTVSSGGGGSGGGGSGGGGSDIQLTQSPAIMSASPGEKVTMTCRASSS VSYMN WYQQKSGTSPKRWIYDTSKVASGVPYRFSGSGSGTSYSLTISSMEAEDAATYYCQQWSSN PLTFGA GTKLELKSHHHHHH (SEQ ID NO: 128) P3A1G1AE3–[WGM]–D3-[G4S]-CD3 TRVDQSPSSLSASVGDRVTITCVLTGTRYGLYSTYWYRKNPGSSDEERISISGRYSESVN KGTKSFTL TISSLQPEDSATYYCRAREARHPWLRQWYDGAGTKVEIKPGVQPAPGGGGSASVNQTPRT ATKETG ESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVNKRAKSFSLRIKDLTV ADSATYYC KAQSGMAISTGSGHGYNWYDGAGTVLTVNGGGGSDIKLQQSGAELARPGASVKMSCKTSG YTFTRY TMHWVKQRPGQGLEWIGYINPSRGYTNYNQKFKDKATLTTDKSSSTAYMQLSSLTSEDSA VYYCAR YYDDHYCLDYWGQGTTLTVSSGGGGSGGGGSGGGGSDIQLTQSPAIMSASPGEKVTMTCR ASSSV SYMNWYQQKSGTSPKRWIYDTSKVASGVPYRFSGSGSGTSYSLTISSMEAEDAATYYCQQ WSSNPL TFGAGTKLELKSHHHHHH (SEQ ID NO:129) Any CD3 binding sequence, and variants thereof, known in the art can be substituted in above. For example: UCL OKT3 sequence (WO2019008379) QVQLVQSGAEVKKPGSSVKVSCKASGYTFTRYTMHWVRQAPGQGLEWMGYINPSRGYTNY NQKFK DRVTITADKSTSTAYMELSSLRSEDTAVYYCARYYDDHYCLDYWGQGTMVTVSSVEGGSG GSGGSG GSGGVDDIQMTQSPSSLSASVGDRVTITCSASSSVSYMNWYQQKPGKAPKRLIYDTSKLA SGVPSRF SGSGSGTEFTLTISSLQPEDFATYYCQQWSSNPFTFGQGTKVEIK (SEQ ID NO: 130) Harpoon ID20 (WO2016187594) DIKLQQSGAELARPGASVKMSCKTSGYTFTRYTMHWVKQRPGQGLEWIGYINPSRGYTNY NQKFKD KATLTTDKSSSTAYMQLSSLTSEDSAVYYCARYYDDHYCLDYWGQGTTLTVSSVEGGSGG SGGSGG SGGVDDIQLTQSPAIMSASPGEKVTMTCRASSSVSYMNWYQQKSGTSPKRWIYDTSKVAS GVPYRF SGSGSGTSYSLTISSMEAEDAATYYCQQWSSNPLTFGAGTKLELK (SEQ ID NO: 131) Fc regions may be engineered to reduce FcγR binding. Therefore, the Fc regions disclosed herein may be engineered to reduce FcγR binding. In one embodiment, the fragment may be a first fragment of an immunoglobulin Fc region which is engineered to dimerize with a second fragment of an immunoglobulin Fc region. For example, the ROR1 specific antigen binding molecule may be fused to a first fragment of an immunoglobulin Fc region and the PTK7 specific binding molecule may be fused to a second fragment of an immunoglobulin Fc region. As used herein, an immunoglobulin Fc region that is “engineered to dimerise” may comprise at least one amino acid substitution. Typically, the at least one amino acid substitution promotes and/or makes more energetically favourable, an interaction and/or association with a second fragment of an immunoglobulin Fc region, which thus promotes dimerization and/or makes dimerization more energetically favourable. Such recombinant fusion proteins may have particular utility in the preparation of bi-specific and/or bi-paratopic binders. Methods for generating Fc based bi-specific and / or bi-paratopic binders, through pairing of two distinct Fc heavy chains that are engineered to dimerize, are known in the art. These methods enable an Fc region to be assembled from two different heavy chains, each fused to a target binding domain or sequence with different binding characteristics. The target binding domains or sequences can be directed to different targets to generate multi-specific binders and/or to different regions or epitopes on the same target to generate bi-paratopic binding proteins. Multiple binding domains or sequences can be fused to the Fc sequences to create multi-specific or multi-paratopic binders or both multi-specific multi-paratopic binders within the same protein. Methods to generate these asymmetric bispecific and/or bi-paratopic binders through heterodimerisation of two different Fc heavy chains, or fragments thereof, include but are not limited to: Knobs-into-holes (Y-T), Knobs-into-holes (CW-CSAV), CH3 charge pair, Fab-arm exchange, SEED technology, BEAT technology, , HA-TF, ZW1 approach, Biclonic approach, EW-RVT and Triomab See for example, Brinkman & Kontermann, (2017) mAbs, 9:2, 182-212; Klein et al (2012) mAbs 4:6, 653–663; Wang et al (2019) Antibodies, 8, 43; and Dietrich et al (2020) BBA - Proteins and Proteomics 1868140250; each of which is incorporated herein by reference in its entirety. In one embodiment, the first fragment of an immunoglobulin Fc region is engineered to dimerize with the second fragment of an immunoglobulin Fc region by a method selected from the group consisting of knobs-into-holes (Y-T), knobs-into-holes (CW-CSAV), CH3 charge pairing, Fab-arm exchange, SEED technology, BEAT technology, HA-TF, ZW1 approach, Biclonic approach, EW-RVT and Triomab. Knobs-into-holes (Y-T) may comprise a T366Y substitution in a first CH3 domain and a Y407T substitution in a second CH3 domain. Knobs-into-holes (CW-CSAV) may comprise one or more (preferably all) of the following substitutions in a first CH3 domain: S354C, T366W. Knobs-into-holes (CW-CSAV) may comprise one or more (preferably all) of the following substitutions in a second CH3 domain: Y349C, T366S, L368A, Y407V. Knobs-into-holes (CW-CSAV) may comprise a disulphide bond in CH3. CH3 charge pairing, may comprise one or more (preferably all) of the following substitutions in a first CH3 domain: K392D, K409D. CH3 charge pairing may comprise one or more (preferably all) of the following substitutions in a second CH3 domain: E356K, D399K. Fab-arm exchange, may comprise a K409R substitution in a first CH3 domain and a F405L substitution in a second CH3 domain. Fab arm exchange and DuoBody capture the same Fc changes. DuoBody technology, may therefore comprise a K409R substitution in a first CH3 domain and a F405L substitution in a second CH3 domain. SEED technology may incorporate known substitutions and/or result in an IgG/A chimera. Complementarity in the CH3 interface allowing for a heterodimeric assembly of Fc chains was developed by designing strand-exchange engineered domain (SEED) heterodimers. These SEED CH3 domains are composed of alternating segments derived from human IgA and IgG CH3 sequences (AG SEED CH3 and GA SEED CH3) and were used to generate so-called SEEDbodies, Davis et al (2010) PEDS 23, 4, 195-202 hereby incorporated by reference in its entirety Because molecular models suggested that interaction with FcRn is impaired in the AG SEED CH3, residues at the CH2-CH3 junction were returned to IgG sequences. Pharmacokinetic studies confirmed that the half-life of SEEDbodies was comparable to other Fc fusion proteins and IgG1. BEAT technology engineers the constant α and ^ domains of the human T cell receptor into the IgG1 CH3 dimer interface to drive heterodimerisation (Skegro et al (2017) JBC 292(23) 9745-9759). An additional D410Q mutation can further increase heterodimer formation in this system (Stutz & Blein 2020 JBC 295(28) 9392-9408). HA-TF, may comprise one or more (preferably all) of the following substitutions in a first CH3 domain: S364H, F405A. HA-TF may comprise one or more (preferably all) of the following substitutions in a second CH3 domain: Y349T, T394F. ZW1 approach, may comprise one or more (preferably all) of the following substitutions in a first CH3 domain: T350V, L351Y, F405A, Y407V. ZW1 approach, may comprise one or more (preferably all) of the following substitutions in a second CH3 domain: T350V, T366L, K392L, T394W. Biclonic approach, may comprise one or more (preferably all) of the following substitutions in a first CH3 domain: 366K (+351K). Biclonic approach, may comprise one or more (preferably all) of the following substitutions in a second CH3 domain: 351D or E or D at 349, 368, 349, or 349 + 355. EW-RVT, may comprise one or more (preferably all) of the following substitutions in a first CH3 domain: K360E, K409W. EW-RVT, may comprise one or more (preferably all) of the following substitutions in a second CH3 domain: Q347R, D399V, F405T. EW-RVT may comprise a disulphide bond in CH3. A disulphide bridge may be supported by the further incorporation of Y349C to a first CH3 domain and S354C to a second CH3 domain. Triomabs may be formed by fusing a mouse hybridoma with a rat hybridoma, resulting in production of a bispecific, assymmetric hybrid IgG molecule. Preferential pairing of light chains with its corresponding heavy chain may then occur. In one embodiment, one or more residues of the fragment of the immunoglobulin Fc region comprises one or more amino acid substitution suitable for heterodimerization with a second fragment of an immunoglobulin Fc region comprising one or more corresponding amino acid substitution. In one embodiment, one or more residues of the fragment of the immunoglobulin Fc region comprises one or more amino acid substitution suitable for knobs-in-holes (KIH) dimerization with a second fragment of an immunoglobulin Fc region comprising one or more corresponding amino acid substitution. The one or more corresponding amino acid substitution may be one or more corresponding amino acid substitution suitable for knobs-in-holes (KIH) dimerization with the first fragment of an immunoglobulin Fc region. In one embodiment, the one or more amino acid substitution is selected from the group consisting of T366Y, Y407T, S354C, T366W, Y349C, T366S, L368A and Y407V. In one embodiment, the one or more amino acid substitution is selected from the group consisting of T366Y and Y407T. The recombinant fusion protein may comprise a sequence according to SEQ ID NO: 146 or SEQ ID NO: 147. G3CP hFc(S239C+Y407T) SEQ ID NO: 146 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLSLSPGK G3CPG4 hFc(S239C+Y407T) SEQ ID NO: 147 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIKGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQ GNVFSCS VMHEALHNHYTQKSLSLSPGK The recombinant fusion protein may comprise a sequence according to SEQ ID NO: 194, SEQ ID NO: 195 or SEQ ID NO 196: 1H8 hFc (S239C+Y407T) SEQ ID NO: 194 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSSVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQ GNVFSCS VMHEALHNHYTQKSLSLSPGK 1H8 G4 hFc (S239C+Y407T) SEQ ID NO: 195 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPSSVQWYDGAGTKVEIKGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQ GNVFSCS VMHEALHNHYTQKSLSLSPGK 1H8 v15 hFc (S239C+Y407T) SEQ ID NO: 196 ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPSSVQWYDGQGTKLEVKGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLSLSPGK The recombinant fusion protein may comprise a sequence according to SEQ ID NO: 148. P3A1 hFc(S239C+T366Y) SEQ ID NO: 148 TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHT CPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVH NAKTKPR EEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLP PSRDELTK NQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQG NVFSCS VMHEALHNHYTQKSLSLSPGK The recombinant fusion protein may comprise a sequence according to SEQ ID NO: 191 or SEQ ID NO: 192: G3CP hFc(S239C+T366Y) SEQ ID NO: 191 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFS CSVMHEALHNHYTQKSLSLSPGK G3CPG4 hFc (S239C+T366Y) SEQ ID NO: 192 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIKGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQ GNVFSC SVMHEALHNHYTQKSLSLSPGK The recombinant fusion protein may comprise a sequence according to SEQ ID NO: 197, SEQ ID NO: 198, or SEQ ID NO: 199 1H8 hFc (S239C+T366Y) SEQ ID NO: 197 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSSVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQ GNVFSC SVMHEALHNHYTQKSLSLSPGK 1H8 G4 hFc (S239C+T366Y) SEQ ID NO: 198 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPSSVQWYDGAGTKVEIKGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQ GNVFSC SVMHEALHNHYTQKSLSLSPGK 1H8 v15 hFc (S239C+T366Y) SEQ ID NO: 199 ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPSSVQWYDGQGTKLEVKGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFS CSVMHEALHNHYTQKSLSLSPGK The recombinant fusion protein may comprise a sequence according to SEQ ID NO: 193: P3A1 hFc (S239C+Y407T) SEQ ID NO: 193: TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHT CPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVH NAKTKPR EEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLP PSRDELTK NQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQG NVFSCSV MHEALHNHYTQKSLSLSPGK The recombinant fusion protein may comprise a sequence according to SEQ ID NO: 550 to 561 G3CP-hFc (S442C + T366Y) (SEQ ID NO: 550) ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFS CSVMHEALHNHYTQKSLCLSPGK G3CPG4 hFc (S442C + T366Y) (SEQ ID NO: 551) TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIKGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQ GNVFSC SVMHEALHNHYTQKSLCLSPGK 1H8 -hFc (S442C + T366Y) (SEQ ID NO: 552) ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSSVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQ GNVFSC SVMHEALHNHYTQKSLCLSPGK 1H8 G4 hFc (S442C + T366Y) (SEQ ID NO: 553) TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPSSVQWYDGAGTKVEIKGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQ GNVFSC SVMHEALHNHYTQKSLCLSPGK 1H8 V15 hFc (S442C + T366Y) (SEQ ID NO: 554) ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPSSVQWYDGQGTKLEVKGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFS CSVMHEALHNHYTQKSLCLSPGK P3A1 hFc (S442C + T366Y) (SEQ ID NO: 555) TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHT CPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVH NAKTKPR EEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLP PSRDELTK NQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQG NVFSCS VMHEALHNHYTQKSLCLSPGK G3CP-hFc (S442C + Y407T) (SEQ ID NO: 556) ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLCLSPGK G3CPG4 hFc (S442C + Y407T) (SEQ ID NO: 557) TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIKGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQ GNVFSCS VMHEALHNHYTQKSLCLSPGK 1H8 -hFc (S442C + Y407T) (SEQ ID NO: 558) ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSSVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQ GNVFSCS VMHEALHNHYTQKSLCLSPGK 1H8 G4 hFc (S442C + Y407T) (SEQ ID NO: 559) TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPSSVQWYDGAGTKVEIKGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQ GNVFSCS VMHEALHNHYTQKSLCLSPGK 1H8 V15 hFc (S442C + Y407T) (SEQ ID NO: 560) ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPSSVQWYDGQGTKLEVKGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLCLSPGK P3A1 hFc (S442C + Y407T) (SEQ ID NO: 561) TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHT CPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVH NAKTKPR EEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLP PSRDELTK NQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQG NVFSCSV MHEALHNHYTQKSLCLSPGK The recombinant fusion protein may comprise a sequence according to any one of SEQ ID NO: 253 to 258 G3CP hFc (S239C & S442C +Y407T) SEQ ID NO: 253 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLCLSPGK G3CPG4 hFc (S239C & S442C +Y407T) SEQ ID NO: 254 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIKGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQ GNVFSCS VMHEALHNHYTQKSLCLSPGK 1H8 hFc (S239C & S442C +Y407T) SEQ ID NO: 255 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSSVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQ GNVFSCS VMHEALHNHYTQKSLCLSPGK 1H8 G4 hFc (S239C & S442C +Y407T) SEQ ID NO: 256 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPSSVQWYDGAGTKVEIKGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQ GNVFSCS VMHEALHNHYTQKSLCLSPGK 1H8 v15 hFc (S239C & S442C +Y407T) SEQ ID NO: 257 ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPSSVQWYDGQGTKLEVKGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLCLSPGK P3A1 hFc (S239C & S442C +Y407T) SEQ ID NO: 258 TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHT CPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVH NAKTKPR EEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLP PSRDELTK NQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQG NVFSCSV MHEALHNHYTQKSLCLSPGK The recombinant fusion protein may comprise a sequence according to any one of SEQ ID NO: 259 to 264 P3A1 hFc (S239C & S442C +T366Y) SEQ ID NO: 259 TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHT CPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVH NAKTKPR EEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLP PSRDELTK NQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQG NVFSCS VMHEALHNHYTQKSLCLSPGK G3CP hFc (S239C & S442C +T366Y) SEQ ID NO: 260 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFS CSVMHEALHNHYTQKSLCLSPGK G3CPG4 hFc (S239C & S442C +T366Y) SEQ ID NO: 261 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIKGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQ GNVFSC SVMHEALHNHYTQKSLCLSPGK 1H8 hFc (S239C & S442C +T366Y) SEQ ID NO: 262 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSSVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQ GNVFSC SVMHEALHNHYTQKSLCLSPGK 1H8 G4 hFc (S239C & S442C +T366Y) SEQ ID NO: 263 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPSSVQWYDGAGTKVEIKGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQ GNVFSC SVMHEALHNHYTQKSLCLSPGK 1H8 v15 hFc (S239C & S442C +T366Y) SEQ ID NO: 264 ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPSSVQWYDGQGTKLEVKGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFS CSVMHEALHNHYTQKSLCLSPGK The recombinant fusion protein may comprise a sequence according to any one of SEQ ID NO: 500 to 502. P2A7 hFc (Y407T+S239C) (SEQ ID NO: 500) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHTC PPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHN AKTKPRE EQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPP SRDELTKN QVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGN VFSCSV MHEALHNHYTQKSLSLSPGK 4D2 hFc (Y407T+S239C) (SEQ ID NO: 501) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSGGGGSGGGGSEPK SSDKT HTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLSLSPGK E02 hFc (Y407T+S239C) (SEQ ID NO: 502) ASVNQTPRTATKETGESLTINCVVTGAGYALAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAFLPPRVWHGVKMQHWYDGAGTVLTVNGGGGSGGGGSGGGGSEP KSSD KTHTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDG VEVHNAK TKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQV YTLPPSRD ELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSR WQQGNVF SCSVMHEALHNHYTQKSLSLSPGK The recombinant fusion protein may comprise a sequence according to any one of SEQ ID NO: 503 to 505 P2A7 hFc (Y407T+S442C) (SEQ ID NO: 503) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHTC PPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHN AKTKPRE EQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPP SRDELTKN QVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGN VFSCSV MHEALHNHYTQKSLCLSPGK 4D2 hFc (Y407T+S442C) (SEQ ID NO: 504) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSGGGGSGGGGSEPK SSDKT HTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLCLSPGK E02 hFc (Y407T+S442C) (SEQ ID NO: 505) ASVNQTPRTATKETGESLTINCVVTGAGYALAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAFLPPRVWHGVKMQHWYDGAGTVLTVNGGGGSGGGGSGGGGSEP KSSD KTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDG VEVHNAK TKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQV YTLPPSRD ELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSR WQQGNVF SCSVMHEALHNHYTQKSLCLSPGK The recombinant fusion protein may comprise a sequence according to any one of SEQ ID NO: 506 to 508. P2A7 hFc (Y407T+S239C+S442C) (SEQ ID NO: 506) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHTC PPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHN AKTKPRE EQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPP SRDELTKN QVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGN VFSCSV MHEALHNHYTQKSLCLSPGK 4D2 hFc (Y407T+S239C+S442C) (SEQ ID NO: 507) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSGGGGSGGGGSEPK SSDKT HTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLCLSPGK E02 hFc (Y407T+S239C+S442C) (SEQ ID NO: 508) ASVNQTPRTATKETGESLTINCVVTGAGYALAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAFLPPRVWHGVKMQHWYDGAGTVLTVNGGGGSGGGGSGGGGSEP KSSD KTHTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDG VEVHNAK TKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQV YTLPPSRD ELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSR WQQGNVF SCSVMHEALHNHYTQKSLCLSPGK The recombinant fusion protein may comprise a sequence according to any one of SEQ ID NO: 509 to 511 P2A7 hFc (T366Y+S239C) (SEQ ID NO: 509) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHTC PPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHN AKTKPRE EQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPP SRDELTKN QVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGN VFSCSV MHEALHNHYTQKSLSLSPGK 4D2 hFc (T366Y+S239C) (SEQ ID NO: 510) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSGGGGSGGGGSEPK SSDKT HTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFS CSVMHEALHNHYTQKSLSLSPGK E02 hFc (T366Y+S239C) (SEQ ID NO: 511) ASVNQTPRTATKETGESLTINCVVTGAGYALAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAFLPPRVWHGVKMQHWYDGAGTVLTVNGGGGSGGGGSGGGGSEP KSSD KTHTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDG VEVHNAK TKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQV YTLPPSRD ELTKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSR WQQGNVF SCSVMHEALHNHYTQKSLSLSPGK The recombinant fusion protein may comprise a sequence according to any one of SEQ ID NO: 512 to 514 P2A7 hFc (T366Y+S442C) (SEQ ID NO: 512) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHTC PPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHN AKTKPRE EQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPP SRDELTKN QVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGN VFSCSV MHEALHNHYTQKSLCLSPGK 4D2 hFc (T366Y+S442C) (SEQ ID NO: 513) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSGGGGSGGGGSEPK SSDKT HTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFS CSVMHEALHNHYTQKSLCLSPGK E02 hFc (T366Y+S442C) (SEQ ID NO: 514) ASVNQTPRTATKETGESLTINCVVTGAGYALAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAFLPPRVWHGVKMQHWYDGAGTVLTVNGGGGSGGGGSGGGGSEP KSSD KTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDG VEVHNAK TKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQV YTLPPSRD ELTKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSR WQQGNVF SCSVMHEALHNHYTQKSLCLSPGK The recombinant fusion protein may comprise a sequence according to any one of SEQ ID NO: 515 to 517 P2A7 hFc (T366Y+S239C+S442C) (SEQ ID NO: 515) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHTC PPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHN AKTKPRE EQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPP SRDELTKN QVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGN VFSCSV MHEALHNHYTQKSLCLSPGK 4D2 hFc (T366Y+S239C+S442C) (SEQ ID NO: 516) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSGGGGSGGGGSEPK SSDKT HTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFS CSVMHEALHNHYTQKSLCLSPGK E02 hFc (T366Y+S239C+S442C) (SEQ ID NO: 517) ASVNQTPRTATKETGESLTINCVVTGAGYALAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAFLPPRVWHGVKMQHWYDGAGTVLTVNGGGGSGGGGSGGGGSEP KSSD KTHTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDG VEVHNAK TKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQV YTLPPSRD ELTKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSR WQQGNVF SCSVMHEALHNHYTQKSLCLSPGK The recombinant fusion protein may be a bi-paratopic dimer comprising any one or any two of SEQ ID NOs 146, 147, 194, 195, 196, 148, 191, 192, 193, 197, 198 and 199. The bi-paratopic dimer may comprise one of SEQ ID NOs 146, 147, 194, 195, 196 and 193 comprising the Y407T point mutation. The bi-paratopic dimer may comprise one of SEQ ID NOs 148, 191, 192, 197, 198 and 199 comprising the T366Y point mutation. The bi-paratopic dimer may comprise SEQ ID NO: 146 and SEQ ID NO: 148 or SEQ ID NO: 147 and SEQ ID NO: 148. Any of the recombinant fusion proteins disclosed herein may be associated with any of the linkers and payloads disclosed herein, Any of the bi-paratopic dimers disclosed herein may be associated with any of the linkers and payloads disclosed herein, Conjugation may be by any one or more S239C or S442C residue in the bi-paratopic dimer. The bi-paratopic dimer may be associated with the linker and payload vc-MMAE. The bi-paratopic dimer may comprise G3CP hFc(S239C+Y407T) (SEQ ID NO: 146) and P3A1 hFc(S239C+T366Y) (SEQ ID NO: 148), conjugated to vc-PAB-EDA-PNU The bi-paratopic dimer may be associated with the linker and payload vc-PAB-EDA-PNU. The bi- paratopic dimer may comprise G3CP hFc(S239C+Y407T) (SEQ ID NO: 146) and P3A1 hFc(S239C+T366Y) (SEQ ID NO: 148), conjugated to vc-PAB-EDA-PNU, or G3CPG4 hFc(S239C+Y407T) (SEQ ID NO: 147) and P3A1 hFc(S239C+T366Y) (SEQ ID NO: 148), conjugated to vc-PAB-EDA-PNU which have been shown to be highly efficacious in vivo. SEQ ID Nos: 146, 147, 194, 195, 196, 148, 191, 192, 193, 197, 198 and 199 include an S239C mutation, for use in conjugation reactions. Where the recombinant fusion protein is not conjugated (for example to an anthracycline (PNU) derivative) the S239C mutation is not needed and position 239 may be an S rather than a C. Accordingly, in alternative embodiments the recombinant fusion protein or bi-paratopic dimer may comprise a sequence according to any one of SEQ ID Nos: 146, 147, 194, 195, 196, 148, 191, 191, 192, 193, 197, 198 and 199 except that each sequence does not include an S239C mutation. The recombinant fusion protein may be a bi-paratopic dimer comprising any one or any two of SEQ ID NO:550 to 561. The bi-paratopic dimer may comprise one of SEQ ID NOs 556 to 561 comprising the Y407T point mutation. The bi-paratopic dimer may comprise one of SEQ ID NOs 550 to 555 comprising the T366Y point mutation. The bi-paratopic dimer may comprise SEQ ID NO: 556 and SEQ ID NO: 555 or SEQ ID NO: 557 and SEQ ID NO: 555. Any of the recombinant fusion proteins disclosed herein may be associated with any of the linkers and payloads disclosed herein, Any of the bi-paratopic dimers disclosed herein may be associated with any of the linkers and payloads disclosed herein, Conjugation may be by any one or more S239C or S442C residue in the bi-paratopic dimer. The bi-paratopic dimer may be associated with the linker and payload vc-MMAE. The bi-paratopic dimer may comprise G3CP hFc(S2442C+Y407T) (SEQ ID NO: 556) and P3A1 hFc(S442C+T366Y) (SEQ ID NO: 555), conjugated to vc-PAB-EDA-PNU The bi-paratopic dimer may be associated with the linker and payload vc-PAB-EDA-PNU. The bi- paratopic dimer may comprise G3CP hFc(S442C+Y407T) (SEQ ID NO: 556) and P3A1 hFc(S442C+T366Y) (SEQ ID NO: 555), conjugated to vc-PAB-EDA-PNU, or G3CPG4 hFc(S442C+Y407T) (SEQ ID NO: 557) and P3A1 hFc(S442C+T366Y) (SEQ ID NO: 555), conjugated to vc-PAB-EDA-PNU which have been shown to be highly efficacious in vivo. SEQ ID Nos: 550 to 561 include an S442C mutation, for use in conjugation reactions. Where the recombinant fusion protein is not conjugated (for example to an anthracycline (PNU) derivative) the S442C mutation is not needed and position 442 may be an S rather than a C. Accordingly, in alternative embodiments the recombinant fusion protein or bi-paratopic dimer may comprise a sequence according to any one of SEQ ID Nos: 550 to 561 except that each sequence does not include an S442C mutation. The bi-paratopic dimers described above comprise either a S442C or a S239C point mutation. Also disclosed herein are bi-paratopic dimers corresponding to those described above comprising both a S442C and S239C. The recombinant fusion protein may comprise a sequence according to SEQ ID NO: 165 or SEQ ID NO: 166. G3CP-hFc (Y407T) SEQ ID NO: 165: ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLSLSPGK G3CP G4-hFc (Y407T) SEQ ID NO: 166: TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIKGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQ GNVFSCS VMHEALHNHYTQKSLSLSPGK The recombinant fusion protein may comprise a sequence according to SEQ ID NO: 200, SEQ ID NO: 201 or SEQ ID NO 202. 1H8 hFc (Y407T) SEQ ID NO: 200 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSSVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQ GNVFSCS VMHEALHNHYTQKSLSLSPGK 1H8 G4 hFc (Y407T) SEQ ID NO: 201 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPSSVQWYDGAGTKVEIKGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQ GNVFSCS VMHEALHNHYTQKSLSLSPGK 1H8 v15 hFc (Y407T) SEQ ID NO: 202 ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPSSVQWYDGQGTKLEVKGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLSLSPGK The recombinant fusion protein may comprise a sequence according to SEQ ID NO: 167: P3A1 hFc (T366Y) SEQ ID NO: 167: TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHT CPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVH NAKTKPR EEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLP PSRDELTK NQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQG NVFSCS VMHEALHNHYTQKSLSLSPGK The recombinant fusion protein may comprise a sequence according to SEQ ID NO: 188 or SEQ ID NO: 189: G3CP hFc(T366Y) SEQ ID NO: 188 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFS CSVMHEALHNHYTQKSLSLSPGK G3CPG4 hFc (T366Y) SEQ ID NO: 189 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIKGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQ GNVFSC SVMHEALHNHYTQKSLSLSPGK The recombinant fusion protein may comprise a sequence according to SEQ ID NO: 203, SEQ ID NO: 204, or SEQ ID NO: 205: 1H8 hFc (T366Y) SEQ ID NO: 203 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSSVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQ GNVFSC SVMHEALHNHYTQKSLSLSPGK 1H8 G4 hFc (T366Y) SEQ ID NO: 204 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPSSVQWYDGAGTKVEIKGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQ GNVFSC SVMHEALHNHYTQKSLSLSPGK 1H8 v15 hFc (T366Y) SEQ ID NO: 205 ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPSSVQWYDGQGTKLEVKGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFS CSVMHEALHNHYTQKSLSLSPGK The recombinant fusion protein may comprise a sequence according to SEQ ID NO: 190: P3A1 hFc (Y407T) SEQ ID NO: 190 TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHT CPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVH NAKTKPR EEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLP PSRDELTK NQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQG NVFSCSV MHEALHNHYTQKSLSLSPGK The recombinant fusion protein may comprise a sequence according to any one of SEQ ID NO: 518 to 520, or a sequence corresponding to any one of SEQ ID NO: 518 to 520 comprising a S239C and/or S442C substitution. P2A7 hFc Y407T (SEQ ID NO: 518) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHTC PPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHN AKTKPRE EQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPP SRDELTKN QVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGN VFSCSV MHEALHNHYTQKSLSLSPGK 4D2 hFc Y407T (SEQ ID NO: 519) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSGGGGSGGGGSEPK SSDKT HTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLSLSPGK E02 hFc Y407T (SEQ ID NO: 520) ASVNQTPRTATKETGESLTINCVVTGAGYALAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAFLPPRVWHGVKMQHWYDGAGTVLTVNGGGGSGGGGSGGGGSEP KSSD KTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDG VEVHNAK TKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQV YTLPPSRD ELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSR WQQGNVF SCSVMHEALHNHYTQKSLSLSPGK The recombinant fusion protein may comprise a sequence according to any one of SEQ ID NO: 521 to 523 P2A7 hFc T366Y (SEQ ID NO: 521) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHTC PPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHN AKTKPRE EQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPP SRDELTKN QVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGN VFSCSV MHEALHNHYTQKSLSLSPGK 4D2 hFc T366Y (SEQ ID NO: 522) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSGGGGSGGGGSEPK SSDKT HTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFS CSVMHEALHNHYTQKSLSLSPGK E02 hFc T366Y (SEQ ID NO: 523) ASVNQTPRTATKETGESLTINCVVTGAGYALAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAFLPPRVWHGVKMQHWYDGAGTVLTVNGGGGSGGGGSGGGGSEP KSSD KTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDG VEVHNAK TKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQV YTLPPSRD ELTKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSR WQQGNVF SCSVMHEALHNHYTQKSLSLSPGK SEQ ID Nos 146 to 148, 165 to 167, 178 to 205, 223 to 236, 253 to 264, 518 to 523, 550 to 561 each comprise a (G4S)3 linker. Also explicitly contemplated herein are the corresponding sequences wherein the (G4S)3 linker is replaced with a (G4S)1 linker. For instance, the recombinant fusion protein may comprise one or more of the following SEQ ID Nos; 297 to 332, 408 to 431, 485 to 496, 524 to 547 and 562 to 573. P3A1 G4S-hFc (S239C+Y407T) SEQ ID NO: 308: TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPCP APELLG GPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQY NSTYRVV SVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQV SLTCLVKG FYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMHEA LHNHYT QKSLSLSPGK G3CP G4S-hFc (S239C+Y407T) SEQ ID NO: 297 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLSLSPGK G3CPG4 G4S-hFc (S239C+Y407T) SEQ ID NO: 298 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIKGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLSLSPGK 1H8 G4S-hFc (S239C+Y407T) SEQ ID NO: 299 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSSVQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLSLSPGK 1H8 G4 G4S-hFc (S239C+Y407T) SEQ ID NO: 300 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPSSVQWYDGAGTKVEIKGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLSLSPGK 1H8 v15 G4S-hFc (S239C+Y407T) SEQ ID NO: 301 ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPSSVQWYDGQGTKLEVKGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLSLSPGK P3A1 G4S-hFc (S239C+T366Y) SEQ ID NO: 302 TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPCP APELLG GPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQY NSTYRVV SVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQV SLYCLVKG FYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEA LHNHYT QKSLSLSPGK G3CP G4S-hFc (S239C+T366Y) SEQ ID NO: 303 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLYCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLSLSPGK G3CPG4 G4S-hFc (S239C+T366Y) SEQ ID NO: 304 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIKGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLYCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLSLSPGK 1H8 G4S-hFc (S239C+T366Y) SEQ ID NO: 305 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSSVQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLYCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLSLSPGK 1H8 G4 G4S-hFc (S239C+T366Y) SEQ ID NO: 306 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPSSVQWYDGAGTKVEIKGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLYCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLSLSPGK 1H8 v15 G4S-hFc (S239C+T366Y) SEQ ID NO: 307 ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPSSVQWYDGQGTKLEVKGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLYCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLSLSPGK P3A1 G4S-hFc (S239C & S442C + Y407T) SEQ ID NO: 309 TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPCP APELLG GPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQY NSTYRVV SVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQV SLTCLVKG FYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMHEA LHNHYT QKSLCLSPGK G3CP G4S-hFc (S239C & S442C +Y407T) SEQ ID NO: 310 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK G3CPG4 G4S-hFc (S239C & S442C +Y407T) SEQ ID NO: 311 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK 1H8 G4S-hFc (S239C & S442C +Y407T) SEQ ID NO: 312 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSSVQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK 1H8 G4 G4S-hFc (S239C & S442C +Y407T) SEQ ID NO: 313 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPSSVQWYDGAGTKVEIKGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK 1H8 v15 G4S-hFc (S239C & S442C +Y407T) SEQ ID NO: 314 ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPSSVQWYDGQGTKLEVKGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK P3A1 G4S-hFc (S239C & S442C +T366Y) SEQ ID NO: 315 TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPCP APELLG GPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQY NSTYRVV SVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQV SLYCLVKG FYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEA LHNHYT QKSLCLSPGK G3CP G4S-hFc (S239C & S442C +T366Y) SEQ ID NO: 316 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLYCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK G3CPG4 G4S-hFc (S239C & S442C +T366Y) SEQ ID NO: 317 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIKGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLYCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK 1H8 G4S-hFc (S239C & S442C +T366Y) SEQ ID NO: 318 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSSVQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLYCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK 1H8 G4 G ₄ S-hFc (S239C & S442C +T366Y) SEQ ID NO: 319 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPSSVQWYDGAGTKVEIKGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLYCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK 1H8 v15 G4S-hFc (S239C & S442C +T366Y) SEQ ID NO: 320 ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPSSVQWYDGQGTKLEVKGGGGSEPKSSDKTHTCPPC PAPELL GGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLYCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK P3A1 G4S-hFc (S442C + Y407T) SEQ ID NO: 321 TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVNGGGGSEPKSSDKTHTSPPCP APELLG GPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQY NSTYRVV SVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQV SLTCLVKG FYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMHEA LHNHYT QKSLCLSPGK G3CP G4S-hFc (S442C +Y407T) SEQ ID NO: 322 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPC PAPELL GGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK G3CPG4 G4S-hFc (S442C +Y407T) SEQ ID NO: 323 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPC PAPELL GGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK 1H8 G4S-hFc (S442C +Y407T) SEQ ID NO: 324 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSSVQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPC PAPELL GGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK 1H8 G4 G4S-hFc (S442C +Y407T) SEQ ID NO: 325 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPSSVQWYDGAGTKVEIKGGGGSEPKSSDKTHTCPPC PAPELL GGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK 1H8 v15 G4S-hFc (S442C +Y407T) SEQ ID NO: 326 ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPSSVQWYDGQGTKLEVKGGGGSEPKSSDKTHTCPPC PAPELL GGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLTCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK P3A1 G4S-hFc (S442C +T366Y) SEQ ID NO: 327 TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPCP APELLG GPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQY NSTYRVV SVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQV SLYCLVKG FYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEA LHNHYT QKSLCLSPGK G3CP G4S-hFc (S442C +T366Y) SEQ ID NO: 328 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPC PAPELL GGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLYCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK G3CPG4 G4S-hFc (S442C +T366Y) SEQ ID NO: 329 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIKGGGGSEPKSSDKTHTCPPC PAPELL GGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLYCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK 1H8 G4S-hFc (S442C +T366Y) SEQ ID NO: 330 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSSVQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPC PAPELL GGPSFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQY NSTYRVV SVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQV SLYCLVKG FYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEA LHNHYT QKSLCLSPGK 1H8 G4 G4S-hFc (S442C +T366Y) SEQ ID NO: 331 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPSSVQWYDGAGTKVEIKGGGGSEPKSSDKTHTCPPC PAPELL GGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLYCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK 1H8 v15 G4S-hFc (S442C +T366Y) SEQ ID NO: 332 ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPSSVQWYDGQGTKLEVKGGGGSEPKSSDKTHTCPPC PAPELL GGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRV VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQ VSLYCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHE ALHNHY TQKSLCLSPGK P2A7 G4S-hFc (Y407T+S239C) (SEQ ID NO: 524) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPCP APELLGG PCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYN STYRVVS VLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVS LTCLVKGF YPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMHEAL HNHYTQ KSLSLSPGK 4D2 G4S-hFc (Y407T+S239C) (SEQ ID NO: 525) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSEPKSSDKTHTCPP CPAPEL LGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREE QYNSTYR VVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKN QVSLTCLV KGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMH EALHNH YTQKSLSLSPGK E02 G4S-hFc (Y407T+S239C) (SEQ ID NO: 526) ASVNQTPRTATKETGESLTINCVVTGAGYALAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAFLPPRVWHGVKMQHWYDGAGTVLTVNGGGGSEPKSSDKTHTCP PCPAPE LLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPRE EQYNSTY RVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTK NQVSLTCL VKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVM HEALHN HYTQKSLSLSPGK P2A7 G4S-hFc (T366Y+S239C) (SEQ ID NO: 527) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPCP APELLGG PCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYN STYRVVS VLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVS LYCLVKGF YPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEAL HNHYTQ KSLSLSPGK 4D2 G4S-hFc (T366Y+S239C) (SEQ ID NO: 528) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSEPKSSDKTHTCPP CPAPEL LGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREE QYNSTYR VVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKN QVSLYCLV KGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMH EALHNH YTQKSLSLSPGK E02 G4S-hFc (T366Y+S239C) (SEQ ID NO: 529) ASVNQTPRTATKETGESLTINCVVTGAGYALAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAFLPPRVWHGVKMQHWYDGAGTVLTVNGGGGSEPKSSDKTHTCP PCPAPE LLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPRE EQYNSTY RVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTK NQVSLYCL VKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVM HEALHN HYTQKSLSLSPGK P2A7 G4S-hFc (T366Y+S239C+S442C) (SEQ ID NO: 530) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPCP APELLGG PCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYN STYRVVS VLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVS LYCLVKGF YPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEAL HNHYTQ KSLCLSPGK 4D2 G4S-hFc (T366Y+S239C+S442C) (SEQ ID NO: 531) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSEPKSSDKTHTCPP CPAPEL LGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREE QYNSTYR VVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKN QVSLYCLV KGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMH EALHNH YTQKSLCLSPGK E02 G4S-hFc (T366Y+S239C+S442C) (SEQ ID NO: 532) ASVNQTPRTATKETGESLTINCVVTGAGYALAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAFLPPRVWHGVKMQHWYDGAGTVLTVNGGGGSEPKSSDKTHTCP PCPAPE LLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPRE EQYNSTY RVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTK NQVSLYCL VKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVM HEALHN HYTQKSLCLSPGK P2A7 G4S-hFc (Y407T+S239C+S442C) (SEQ ID NO: 533) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPCP APELLGG PCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYN STYRVVS VLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVS LTCLVKGF YPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMHEAL HNHYTQ KSLCLSPGK P2A7 G4S-hFc (Y407T+S442C) (SEQ ID NO: 534) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPCP APELLGG PSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYN STYRVVS VLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVS LTCLVKGF YPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMHEAL HNHYTQ KSLCLSPGK 4D2 G4S-hFc (Y407T+S442C) (SEQ ID NO: 535) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSEPKSSDKTHTCPP CPAPEL LGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREE QYNSTYR VVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKN QVSLTCLV KGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMH EALHNH YTQKSLCLSPGK E02 G4S-hFc (Y407T+S442C) (SEQ ID NO: 536) ASVNQTPRTATKETGESLTINCVVTGAGYALAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAFLPPRVWHGVKMQHWYDGAGTVLTVNGGGGSEPKSSDKTHTCP PCPAPE LLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPRE EQYNSTY RVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTK NQVSLTCL VKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVM HEALHN HYTQKSLCLSPGK P2A7 G4S-hFc (T366Y+S442C) (SEQ ID NO: 537) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPCP APELLGG PSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYN STYRVVS VLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVS LYCLVKGF YPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEAL HNHYTQ KSLCLSPGK 4D2 G4S-hFc (T366Y+S442C) (SEQ ID NO: 538) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSEPKSSDKTHTCPP CPAPEL LGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREE QYNSTYR VVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKN QVSLYCLV KGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMH EALHNH YTQKSLCLSPGK E02 G4S-hFc (T366Y+S442C) (SEQ ID NO: 539) ASVNQTPRTATKETGESLTINCVVTGAGYALAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAFLPPRVWHGVKMQHWYDGAGTVLTVNGGGGSEPKSSDKTHTCP PCPAPE LLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPRE EQYNSTY RVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTK NQVSLYCL VKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVM HEALHN HYTQKSLCLSPGK 4D2 G4S-hFc (Y407T+S239C+S442C) (SEQ ID NO: 540) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSEPKSSDKTHTCPP CPAPEL LGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREE QYNSTYR VVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKN QVSLTCLV KGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMH EALHNH YTQKSLCLSPGK E02 G4S-hFc (Y407T+S239C+S442C) (SEQ ID NO: 541) ASVNQTPRTATKETGESLTINCVVTGAGYALAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAFLPPRVWHGVKMQHWYDGAGTVLTVNGGGGSEPKSSDKTHTCP PCPAPE LLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPRE EQYNSTY RVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTK NQVSLTCL VKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVM HEALHN HYTQKSLCLSPGK P2A7 G4S hFc (Y407T) (SEQ ID NO: 542) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPCP APELLGG PSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYN STYRVVS VLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVS LTCLVKGF YPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMHEAL HNHYTQ KSLSLSPGK 4D2 G4S hFc (Y407T) (SEQ ID NO: 543) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSEPKSSDKTHTCPP CPAPEL LGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREE QYNSTYR VVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKN QVSLTCLV KGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMH EALHNH YTQKSLSLSPGK E02 G4S hFc (Y407T) (SEQ ID NO: 544) ASVNQTPRTATKETGESLTINCVVTGAGYALAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAFLPPRVWHGVKMQHWYDGAGTVLTVNGGGGSEPKSSDKTHTCP PCPAPE LLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPRE EQYNSTY RVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTK NQVSLTCL VKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVM HEALHN HYTQKSLSLSPGK P2A7 G4S hFc (T366Y) (SEQ ID NO: 545) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPCP APELLGG PSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYN STYRVVS VLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVS LYCLVKGF YPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEAL HNHYTQ KSLSLSPGK 4D2 G4S hFc (T366Y) (SEQ ID NO: 546) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSEPKSSDKTHTCPP CPAPEL LGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREE QYNSTYR VVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKN QVSLYCLV KGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMH EALHNH YTQKSLSLSPGK E02 G4S hFc (T366Y) (SEQ ID NO: 547) ASVNQTPRTATKETGESLTINCVVTGAGYALAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAFLPPRVWHGVKMQHWYDGAGTVLTVNGGGGSEPKSSDKTHTCP PCPAPE LLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPRE EQYNSTY RVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTK NQVSLYCL VKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVM HEALHN HYTQKSLSLSPGK G3CP-G4S - hFc (Y407T) (SEQ ID NO: 562) ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSLRIKDLTVADS ATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPCPAPELLGGPS VFLFPPKPKDTLMIS RTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWL NGKEYKCKVSNKALP APIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPEN NYKTTPPVLDSDGSFFLT SKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK G3CP G4 G4S-hFc (Y407T) (SEQ ID NO: 563) TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTLTISSLQPEDSA TYYCRAYPWGAGAPYNVQWYDGAGTKVEIKGGGGSEPKSSDKTHTCPPCPAPELLGGPSV FLFPPKPKDTLMISRT PEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNG KEYKCKVSNKALPA PIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENN YKTTPPVLDSDGSFFLTSK LTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK P3A1 G4S hFc (Y407T) (SEQ ID NO: 564) TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFSLRIKDLTVAD SATYYCKAREARHPWLRQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPCPAPELLGGPSV FLFPPKPKDTLMISRT PEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNG KEYKCKVSNKALPA PIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENN YKTTPPVLDSDGSFFLTSK LTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK 1H8 G4ShFc (Y407T) (SEQ ID NO: 565 ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSLRIKDLTVADS ATYYCKAYPWGAGAPSSVQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPCPAPELLGGPS VFLFPPKPKDTLMIS RTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWL NGKEYKCKVSNKALP APIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPEN NYKTTPPVLDSDGSFFLT SKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK 1H8 G4 G4S hFc (Y407T) (SEQ ID NO: 566 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTLTISSLQPEDSA TYYCRAYPWGAGAPSSVQWYDGAGTKVEIKGGGGSEPKSSDKTHTCPPCPAPELLGGPSV FLFPPKPKDTLMISRT PEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNG KEYKCKVSNKALPA PIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENN YKTTPPVLDSDGSFFLTSK LTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK 1H8 v15 G4S hFc (Y407T) (SEQ ID NO: 567 ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSLRISSLTVEDSA TYYCKAYPWGAGAPSSVQWYDGQGTKLEVKGGGGSEPKSSDKTHTCPPCPAPELLGGPSV FLFPPKPKDTLMISRT PEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNG KEYKCKVSNKALPA PIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENN YKTTPPVLDSDGSFFLTSK LTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK P3A1G4S hFc (T366Y) (SEQ ID NO: 568 TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFSLRIKDLTVAD SATYYCKAREARHPWLRQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPCPAPELLGGPSV FLFPPKPKDTLMISRT PEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNG KEYKCKVSNKALPA PIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLYCLVKGFYPSDIAVEWESNGQPENN YKTTPPVLDSDGSFFLYSK LTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK G3CP G4ShFc(T366Y) (SEQ ID NO: 569 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTLTISSLQPEDSA TYYCRAYPWGAGAPYNVQWYDGAGTKVEIKGGGGSEPKSSDKTHTCPPCPAPELLGGPSV FLFPPKPKDTLMISRT PEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNG KEYKCKVSNKALPA PIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLYCLVKGFYPSDIAVEWESNGQPENN YKTTPPVLDSDGSFFLYSK LTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK G3CPG4 G4S hFc (T366Y) (SEQ ID NO: 570) TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTLTISSLQPEDSA TYYCRAYPWGAGAPYNVQWYDGAGTKVEIKGGGGSEPKSSDKTHTCPPCPAPELLGGPSV FLFPPKPKDTLMISRT PEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNG KEYKCKVSNKALPA PIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLYCLVKGFYPSDIAVEWESNGQPENN YKTTPPVLDSDGSFFLYSK LTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK 1H8 G4ShFc (T366Y) (SEQ ID NO: 571) ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSLRIKDLTVADS ATYYCKAYPWGAGAPSSVQWYDGAGTVLTVNGGGGSEPKSSDKTHTCPPCPAPELLGGPS VFLFPPKPKDTLMIS RTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWL NGKEYKCKVSNKALP APIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLYCLVKGFYPSDIAVEWESNGQPEN NYKTTPPVLDSDGSFFLY SKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK 1H8 G4 G4ShFc (T366Y) (SEQ ID NO: 572) TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTLTISSLQPEDSA TYYCRAYPWGAGAPSSVQWYDGAGTKVEIKGGGGSEPKSSDKTHTCPPCPAPELLGGPSV FLFPPKPKDTLMISRT PEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNG KEYKCKVSNKALPA PIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLYCLVKGFYPSDIAVEWESNGQPENN YKTTPPVLDSDGSFFLYSK LTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK 1H8 v15 G4ShFc (T366Y) (SEQ ID NO: 573) ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSLRISSLTVEDSA TYYCKAYPWGAGAPSSVQWYDGQGTKLEVKGGGGSEPKSSDKTHTCPPCPAPELLGGPSV FLFPPKPKDTLMISRT PEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNG KEYKCKVSNKALPA PIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLYCLVKGFYPSDIAVEWESNGQPENN YKTTPPVLDSDGSFFLYSK LTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK In any embodiment, a specific binding molecule comprising an amino acid sequence represented by formula (I), a (G4S)3 linker and a fragment of an immunoglobulin Fc region may be substituted for a corresponding specific binding molecule comprising an amino acid sequence represented by formula (I), a (G4S)1 linker and a fragment of an immunoglobulin Fc region and vice versa. According to a fourth aspect, the invention provides a recombinant fusion protein dimer comprising (a) a first recombinant fusion protein, wherein the first recombinant fusion protein comprises a receptor tyrosine kinase-like orphan receptor 1 (ROR1) specific antigen binding molecule comprising an amino acid sequence represented by the formula (I): FW1-CDR1-FW2-HV2-FW3a-HV4-FW3b-CDR3-FW4 (I) wherein CDR3 is a CDR sequence having an amino acid sequence selected from the group consisting of YPWGAGAPYNVQWY (SEQ ID NO: 23), YPWGAGAPYLVQWY (SEQ ID NO: 20), YPWGAGAPWNVQWY (SEQ ID NO: 24), YPSGAGAPRPVQWY (SEQ ID NO: 11), YPWGAGAPCLVQWY (SEQ ID NO: 12), YPWGAGAPRLVQWY (SEQ ID NO: 13), YPWGAGAPRQVQWY (SEQ ID NO: 14), YPWGAGAPRSVQWY (SEQ ID NO: 15), YPWGAGAPSLVQWY (SEQ ID NO: 16), YPWGAGAPSNVQWY (SEQ ID NO: 17), YPWGAGAPSQVQWY (SEQ ID NO: 18), YPWGAGAPSSVQWY (SEQ ID NO: 19), YPWGAGAPWQVQWY (SEQ ID NO: 21), YPWGAGAPWSVQWY (SEQ ID NO: 22), and YPWGAGAPWLVQWY (SEQ ID NO: 10); CDR1 is a CDR sequence having an amino acid sequence selected from the group consisting of GANYGLAA (SEQ ID NO: 1), DANYGLAA (SEQ ID NO: 5), GANYDLSA (SEQ ID NO: 2), GANYGLSA (SEQ ID NO: 3), and GANYDLAA (SEQ ID NO: 4) FW1 is a framework region; FW2 is a framework region; HV2 is a hypervariable sequence having an amino acid sequence selected from the group consisting of SSNQERISIS (SEQ ID NO: 6), and SSNKERISIS (SEQ ID NO: 7); FW3a is a framework region; HV4 is a hypervariable sequence having an amino acid sequence selected from the group consisting of NKRTM (SEQ ID NO: 8) and NKGTM (SEQ ID NO: 9); FW3b is a framework region; FW4 is a framework region; wherein if CDR3 is YPWGAGAPWLVQWY (SEQ ID NO: 10) then CDR1 is selected from the group consisting of DANYGLAA (SEQ ID NO: 5), GANYGLSA (SEQ ID NO: 3) and GANYDLAA (SEQ ID NO: 4), and wherein the first antigen binding molecule is fused to a first fragment of an immunoglobulin Fc region engineered to dimerize with a second fragment of an immunoglobulin Fc region; , and (b) a second recombinant fusion protein, wherein the second recombinant fusion protein comprises a protein tyrosine kinase 7 (PTK7) specific antigen binding molecule fused to a second fragment of an immunoglobulin Fc region engineered to dimerize with the first fragment of an immunoglobulin Fc region. In one embodiment, the second fragment of an immunoglobulin Fc region selected from the group consisting of an Fc heavy chain, a CH2 region and a CH3 region. In one embodiment, the second fragment of an immunoglobulin Fc region is an Fc heavy chain. In one embodiment, the second fragment of an immunoglobulin Fc region is engineered to dimerize with the second fragment of an immunoglobulin Fc region by a method selected from the group consisting of knobs-into-holes (Y-T), knobs-into-holes (CW-CSAV), CH3 charge pairing, Fab-arm exchange, SEED technology, BEAT technology, HA-TF, ZW1 approach, Biclonic approach, EW-RVT and Triomab. One or more residues of the first fragment of an immunoglobulin Fc region comprises one or more amino acid substitution suitable for knobs-in-holes (KIH) dimerization with the second fragment of an immunoglobulin Fc region comprising one or more corresponding amino acid substitutions suitable for knobs-in-holes (KIH) dimerization with the first fragment of an immunoglobulin Fc region. One or more residues of the second fragment of an immunoglobulin Fc region comprises one or more amino acid substitution suitable for knobs-in-holes (KIH) dimerization with the first fragment of an immunoglobulin Fc region comprising one or more corresponding amino acid substitutions suitable for knobs-in-holes (KIH) dimerization with the second fragment of an immunoglobulin Fc region. In one embodiment, the one or more amino acid substitution is selected from the group consisting of T366Y, Y407T, S354C, T366W, Y349C, T366S, L368A and Y407V. The skilled person knows which amino acid substitutions represent a “knob” and which amino acid substitutions represent a “hole” and therefore which mutation is suitable for KIH dimerization with a corresponding mutation. For example, T366Y is a knob variant and Y407T is a hole variant. When the first fragment of the immunoglobulin Fc region comprises T366Y, the second fragment of the immunoglobulin Fc region may comprise Y407T, and vice versa. In one embodiment, the one or more amino acid substitution is selected from the group consisting of T366Y and Y407T. Any sequence of a recombinant fusion protein disclosed herein may comprise any one or more amino acid substitution selected from the group consisting of T366Y, Y407T, S354C, T366W, Y349C, T366S, L368A and Y407V. SEQ ID NO: 145 (human Fc region) may therefore be modified by the incorporation of any one or more amino acid substitution selected from the group consisting of T366Y, Y407T, S354C, T366W, Y349C, T366S, L368A and Y407V and incorporated into a recombinant fusion protein as described herein in place of the human Fc region sequence. In one embodiment, the second specific antigen binding molecule is an immunoglobin, an immunoglobin Fab region, a Fab’, a Fv, a Fv-Fc, a single chain Fv (scFv), scFv-Fc, (scFv)2, a diabody, a triabody, a tetrabody, a bispecific t-cell engager (BiTE), an intein, a VNAR domain, a single domain antibody (sdAb) or a VH domain. The ROR1 specific antigen binding molecule may comprise any ROR1 specific antigen binding molecule disclosed herein. The ROR1 specific antigen binding molecule may for instance comprise G3CP, 1H8 or G3CPG4. The PTK7 specific antigen binding molecule may comprise any PTK7 specific antigen binding molecule disclosed herein. The PTK7 specific antigen binding molecule may for instance comprise P2A2, P2A7, P2B1, P2B12, P2C6, P2C7, P2F8, P2G3, P2H9, 4A12, 4C7, 4E5, 4H3, 4D2, E02, PB4, PC2 or a derivative thereof. A derivative of a PTK7 specific antigen binding molecules such as P2A2, P2A7, P2B1, P2B12, P2C6, P2C7, P2F8, P2G3, P2H9, 4A12, 4C7, 4E5, 4H3, 4D2, E02, PB4, or PC2, may be a humanised sequence of P2A2, P2A7, P2B1, P2B12, P2C6, P2C7, P2F8, P2G3, P2H9, 4A12, 4C7, 4E5, 4H3, 4D2, E02, PB4, or PC2 respectively. The PTK7 specific antigen binding molecule may comprise P2A2, P2A7, P2B1, P2B12, P2C6, P2C7, P2F8, P2G3, P2H9, 4A12, 4C7, 4E5, 4H3, 4D2, E02, PB4, or PC2. In one embodiment: (a) the first recombinant fusion protein comprises G3CP, 1H8 or G3CPG4, and (b) the second recombinant fusion protein comprises P2A7, 4D2, or E02. The first recombinant fusion protein may comprise a ROR1 specific antigen binding molecule, such as G3CP, 1H8 or G3CPG4, fused to an Fc heavy chain, optionally via a [G4S]x linker. The first fragment of an immunoglobulin Fc region may be a first Fc heavy chain. The second fragment of an immunoglobulin Fc region may be a second Fc heavy chain. One or more residues of the first Fc heavy chain may comprise one or more amino acid substitution suitable for knobs-in-holes (KIH) dimerization with the second Fc heavy chain comprising one or more corresponding amino acid substitutions suitable for knobs-in-holes (KIH) dimerization with the first Fc heavy chain. The one or more amino acid substitution may be selected from the group consisting of T366Y and Y407T. The first Fc heavy chain may comprise a S239C and/or a S442C mutation. The second Fc heavy chain may comprise a S239C and/or a S442C mutation. The second recombinant fusion protein may comprise a PTK7 specific antigen binding molecule, such as P2A7, 4D2, or E02, fused to an Fc heavy chain, optionally via a [G ₄ S] _x linker. The first fragment of an immunoglobulin Fc region may be a first Fc heavy chain. The second fragment of an immunoglobulin Fc region may be a second Fc heavy chain. One or more residues of the second Fc heavy chain may comprise one or more amino acid substitution suitable for knobs-in-holes (KIH) dimerization with the first Fc heavy chain comprising one or more corresponding amino acid substitutions suitable for knobs- in-holes (KIH) dimerization with the second Fc heavy chain. The one or more amino acid substitution may be selected from the group consisting of T366Y and Y407T. The first Fc heavy chain may comprise a S239C and/or a S442C mutation. The second Fc heavy chain may comprise a S239C and/or a S442C mutation. In one embodiment: (a) the first recombinant fusion protein comprises G3CP-hFc, 1H8-hFc or G3CPG4-hFc, and (b) the second recombinant fusion protein comprises P2A7, 4D2, or E02. In one embodiment: (a) the first recombinant fusion protein comprises G3CP-hFc (S239C), 1H8-hFc (S239C) or G3CPG4-hFc (S239C), and (b) the second recombinant fusion protein comprises P2A7-hFc (S239C), 4D2-hFc (S239C) or E02- hFc (S239C). The recombinant fusion protein dimer may be selected from the group consisting of: G3CP-hFc (S239C) and P2A7-hFc (S239C), G3CP-hFc (S239C) and 4D2-hFc (S239C), and G3CP-hFc (S239C) and E02-hFc (S239C); wherein the ROR1-specific binding molecule is fused to the hFc region via a [G ₄ S] ₃ linker or a G ₄ S linker and wherein (a) the hFc region fused to the ROR1-specific binding molecule comprises a T366Y substitution and the hFc region fused to the PTK7-specific binding molecule comprises a Y407T substitution, or (b) the hFc region fused to the ROR1-specific binding molecule comprises a Y407T substitution and the hFc region fused to the PTK7-specific binding molecule comprises a T366Y substitution. The recombinant fusion protein dimer may be selected from the group consisting of: G3CPG4-hFc (S239C) and P2A7-hFc (S239C), G3CPG4-hFc (S239C) and 4D2-hFc (S239C), and G3CPG4-hFc (S239C) and E02-hFc (S239C); wherein the ROR1-specific binding molecule is fused to the hFc region via a [G4S]3 linker or a G4S linker and wherein (a) the hFc region fused to the ROR1-specific binding molecule comprises a T366Y substitution and the hFc region fused to the PTK7-specific binding molecule comprises a Y407T substitution, or (b) the hFc region fused to the ROR1-specific binding molecule comprises a Y407T substitution and the hFc region fused to the PTK7-specific binding molecule comprises a T366Y substitution. The recombinant fusion protein dimer may be selected from the group consisting of: 1H8-hFc (S239C) and P2A7-hFc (S239C), 1H8-hFc (S239C) and 4D2-hFc (S239C), and 1H8-hFc (S239C) and E02-hFc (S239C); wherein the ROR1-specific binding molecule is fused to the hFc region via a [G4S]3 linker or a G4S linker and wherein (a) the hFc region fused to the ROR1-specific binding molecule comprises a T366Y substitution and the hFc region fused to the PTK7-specific binding molecule comprises a Y407T substitution, or (b) the hFc region fused to the ROR1-specific binding molecule comprises a Y407T substitution and the hFc region fused to the PTK7-specific binding molecule comprises a T366Y substitution. In one embodiment: (a) the first recombinant fusion protein comprises G3CP-hFc (S442C), 1H8-hFc (S442C) or G3CPG4-hFc (S442C), and (b) the second recombinant fusion protein comprises P2A7-hFc (S442C), 4D2-hFc (S442C) or E02- hFc (S442C). The recombinant fusion protein dimer may be selected from the group consisting of: G3CP-hFc (S442C) and P2A7-hFc (S442C), G3CP-hFc (S442C) and 4D2-hFc (S442C), and G3CP-hFc (S442C) and E02-hFc (S442C); wherein the ROR1-specific binding molecule is fused to the hFc region via a [G4S]3 linker or a G4S linker and wherein (a) the hFc region fused to the ROR1-specific binding molecule comprises a T366Y substitution and the hFc region fused to the PTK7-specific binding molecule comprises a Y407T substitution, or (b) the hFc region fused to the ROR1-specific binding molecule comprises a Y407T substitution and the hFc region fused to the PTK7-specific binding molecule comprises a T366Y substitution. The recombinant fusion protein dimer may be selected from the group consisting of: G3CPG4-hFc (S442C) and P2A7-hFc (S442C), G3CPG4-hFc (S442C) and 4D2-hFc (S442C), and G3CPG4-hFc (S442C) and E02-hFc (S442C); wherein the ROR1-specific binding molecule is fused to the hFc region via a [G4S]3 linker or a G4S linker and wherein (a) the hFc region fused to the ROR1-specific binding molecule comprises a T366Y substitution and the hFc region fused to the PTK7-specific binding molecule comprises a Y407T substitution, or (b) the hFc region fused to the ROR1-specific binding molecule comprises a Y407T substitution and the hFc region fused to the PTK7-specific binding molecule comprises a T366Y substitution. The recombinant fusion protein dimer may be selected from the group consisting of: 1H8-hFc (S442C) and P2A7-hFc (S442C), 1H8-hFc (S442C) and 4D2-hFc (S442C), and 1H8-hFc (S442C) and E02-hFc (S442C); wherein the ROR1-specific binding molecule is fused to the hFc region via a [G4S]3 linker or a G4S linker and wherein (a) the hFc region fused to the ROR1-specific binding molecule comprises a T366Y substitution and the hFc region fused to the PTK7-specific binding molecule comprises a Y407T substitution, or (b) the hFc region fused to the ROR1-specific binding molecule comprises a Y407T substitution and the hFc region fused to the PTK7-specific binding molecule comprises a T366Y substitution. In one embodiment: (a) the first recombinant fusion protein comprises G3CP-hFc (S239C & S442C), 1H8-hFc (S239C & S442C) or G3CPG4-hFc (S239C & S442C), and (b) the second recombinant fusion protein comprises P2A7-hFc (S239C & S442C), 4D2-hFc (S239C & S442C), or E02-hFc (S239C & S442C). The recombinant fusion protein dimer may be selected from the group consisting of: G3CP-hFc (S239C & S442C) and P2A7-hFc (S239C & S442C), G3CP-hFc (S239C & S442C) and 4D2-hFc (S239C & S442C), and G3CP-hFc (S239C & S442C) and E02-hFc (S239C & S442C); wherein the ROR1-specific binding molecule is fused to the hFc region via a [G4S]3 linker or a G4S linker and wherein (a) the hFc region fused to the ROR1-specific binding molecule comprises a T366Y substitution and the hFc region fused to the PTK7-specific binding molecule comprises a Y407T substitution, or (b) the hFc region fused to the ROR1-specific binding molecule comprises a Y407T substitution and the hFc region fused to the PTK7-specific binding molecule comprises a T366Y substitution. The recombinant fusion protein dimer may be selected from the group consisting of: G3CPG4-hFc (S239C & S442C) and P2A7-hFc (S239C & S442C), G3CPG4-hFc (S239C & S442C) and 4D2-hFc (S239C & S442C), and G3CPG4-hFc (S239C & S442C) and E02-hFc (S239C & S442C); wherein the ROR1-specific binding molecule is fused to the hFc region via a [G4S]3 linker or a G4S linker and wherein (a) the hFc region fused to the ROR1-specific binding molecule comprises a T366Y substitution and the hFc region fused to the PTK7-specific binding molecule comprises a Y407T substitution, or (b) the hFc region fused to the ROR1-specific binding molecule comprises a Y407T substitution and the hFc region fused to the PTK7-specific binding molecule comprises a T366Y substitution. The recombinant fusion protein dimer may be selected from the group consisting of: 1H8-hFc (S239C & S442C) and P2A7-hFc (S239C & S442C), 1H8-hFc (S239C & S442C) and 4D2-hFc (S239C & S442C), and 1H8-hFc (S239C & S442C) and E02-hFc (S239C & S442C); wherein the ROR1-specific binding molecule is fused to the hFc region via a [G4S]3 linker or a G4S linker and wherein (a) the hFc region fused to the ROR1-specific binding molecule comprises a T366Y substitution and the hFc region fused to the PTK7-specific binding molecule comprises a Y407T substitution, or (b) the hFc region fused to the ROR1-specific binding molecule comprises a Y407T substitution and the hFc region fused to the PTK7-specific binding molecule comprises a T366Y substitution. In alternatives, the recombinant fusion protein dimers described above may comprise any other ROR1- specific binding molecule described herein in place of G3CP, 1H8 or G3CPG4. In alternatives, the recombinant fusion protein dimers described above may comprise any other PTK7- specific binding molecule described herein in place of P2A7, 4D2, or E02. Any of the recombinant fusion protein dimers disclosed herein may be associated with any of the linkers and payloads disclosed herein, Conjugation may be by any one or more S239C or S442C residue in the recombinant fusion protein dimer. Typically where conjugation is by a S239C residue in a first hFc region of the recombinant fusion protein dimer, conjugation will also be by a S239C residue in a second hFc region of the recombinant fusion protein dimer. Typically where conjugation is by a S442C residue in a first hFc region of the recombinant fusion protein dimer, conjugation will also be by a S442C residue in a second hFc region of the recombinant fusion protein dimer. Typically where conjugation is by a S239C and a S442C residue in a first hFc region of the recombinant fusion protein dimer, conjugation will also be by a S239C and a S442C residue in a second hFc region of the recombinant fusion protein dimer. According to a fifth aspect, the invention provides a recombinant fusion protein dimer comprising: (a) a first recombinant fusion protein, wherein the first recombinant fusion protein comprises a receptor tyrosine kinase-like orphan receptor 1 (ROR1) specific antigen binding molecule comprising an amino acid sequence represented by the formula (I): FW1-CDR1-FW2-HV2-FW3a-HV4-FW3b-CDR3-FW4 (I) wherein CDR1 is a CDR sequence having an amino acid sequence selected from the group consisting of GTRYGLYS (SEQ ID NO: 25), GTRYGLYSS (SEQ ID NO: 26), DTRYALYS (SEQ ID NO: 27), DTRYALYSS (SEQ ID NO: 28), GTKYGLYA (SEQ ID NO: 29), GTKYGLYAS (SEQ ID NO: 30) and DTSYGLYS (SEQ ID NO:207); FW1 is a framework region; FW2 is a framework region; HV2 is a hypervariable sequence having an amino acid sequence selected from the group consisting of SSDEERISIS (SEQ ID NO: 31), STDEERISIG (SEQ ID NO: 32), SPNKDRMIIG (SEQ ID NO: 33), STDKERIIIG (SEQ ID NO: 34) and TTDWERMSIG (SEQ ID NO:208); FW3a is a framework region; HV4 is a hypervariable sequence having an amino acid sequence selected from the group consisting of NKGTK (SEQ ID NO: 35), NKGSK (SEQ ID NO: 36), NNGTK (SEQ ID NO: 37), NNRSK (SEQ ID NO: 38) and NKGAK (SEQ ID NO:209); FW3b is a framework region; CDR3 is a CDR sequence having an amino acid sequence according to REARHPWLRQWY (SEQ ID NO: 39); FW4 is a framework region, and wherein the first antigen binding molecule is fused to a first fragment of an immunoglobulin Fc region engineered to dimerize with a second fragment of an immunoglobulin Fc region; and (b) a second recombinant fusion protein, wherein the second recombinant fusion protein comprises a protein tyrosine kinase 7 (PTK7) specific antigen binding molecule fused to a second fragment of an immunoglobulin Fc region engineered to dimerize with the first fragment of an immunoglobulin Fc region. In one embodiment: (a) the first recombinant fusion protein comprises P3A1, and (b) the second recombinant fusion protein comprises P2A7, 4D2, or E02. In one embodiment: (a) the first recombinant fusion protein comprises P3A1-hFc, and (b) the second recombinant fusion protein comprises P2A7-hFc, 4D2-hFc, or E02-hFc. In one embodiment: (a) the first recombinant fusion protein comprises P3A1-hFc (S239C), and (b) the second recombinant fusion protein comprises P2A7-hFc (S239C), 4D2-hFc (S239C), or E02- hFc (S239C). In one embodiment: (a) the first recombinant fusion protein comprises P3A1-hFc (S239C), and (b) the second recombinant fusion protein comprises P2A7-hFc (S239C), 4D2-hFc (S239C), or E02- hFc (S239C). The recombinant fusion protein dimer may be selected from the group consisting of: P3A1-hFc (S239C) and P2A7-hFc (S239C), P3A1-hFc (S239C) and 4D2-hFc (S239C), and P3A1-hFc (S239C) and E02-hFc (S239C); wherein the ROR1-specific binding molecule is fused to the hFc region via a [G4S]3 linker or a G4S linker and wherein (a) the hFc region fused to the ROR1-specific binding molecule comprises a T366Y substitution and the hFc region fused to the PTK7-specific binding molecule comprises a Y407T substitution, or (b) the hFc region fused to the ROR1-specific binding molecule comprises a Y407T substitution and the hFc region fused to the PTK7-specific binding molecule comprises a T366Y substitution. In one embodiment: (a) the first recombinant fusion protein comprises P3A1-hFc (S442C), and (b) the second recombinant fusion protein comprises P2A7-hFc (S442C), 4D2-hFc (S442C), or E02- hFc (S442C). In one embodiment: (a) the first recombinant fusion protein comprises P3A1-hFc (S442C), and (b) the second recombinant fusion protein comprises P2A7-hFc (S442C), 4D2-hFc (S442C), or E02- hFc (S442C). The recombinant fusion protein dimer may be selected from the group consisting of: P3A1-hFc (S442C) and P2A7-hFc (S442C), P3A1-hFc (S442C) and 4D2-hFc (S442C), and P3A1-hFc (S442C) and E02-hFc (S442C); wherein the ROR1-specific binding molecule is fused to the hFc region via a [G ₄ S] ₃ linker or a G ₄ S linker and wherein (a) the hFc region fused to the ROR1-specific binding molecule comprises a T366Y substitution and the hFc region fused to the PTK7-specific binding molecule comprises a Y407T substitution, or (b) the hFc region fused to the ROR1-specific binding molecule comprises a Y407T substitution and the hFc region fused to the PTK7-specific binding molecule comprises a T366Y substitution. In one embodiment: (a) the first recombinant fusion protein comprises P3A1-hFc (S239C & S442C), and (b) the second recombinant fusion protein comprises P2A7-hFc (S239C & S442C), 4D2-hFc (S239C & S442C), or E02-hFc (S239C & S442C). In one embodiment: (a) the first recombinant fusion protein comprises P3A1-hFc (S239C & S442C), and (b) the second recombinant fusion protein comprises P2A7-hFc (S239C & S442C), 4D2-hFc (S239C & S442C), or E02-hFc (S239C & S442C). The recombinant fusion protein dimer may be selected from the group consisting of: P3A1-hFc (S239C & S442C) and P2A7-hFc (S239C & S442C), P3A1-hFc (S239C & S442C) and 4D2-hFc (S239C & S442C), and P3A1-hFc (S239C & S442C) and E02-hFc (S239C & S442C); wherein the ROR1-specific binding molecule is fused to the hFc region via a [G4S]3 linker or a G4S linker and wherein (a) the hFc region fused to the ROR1-specific binding molecule comprises a T366Y substitution and the hFc region fused to the PTK7-specific binding molecule comprises a Y407T substitution, or (b) the hFc region fused to the ROR1-specific binding molecule comprises a Y407T substitution and the hFc region fused to the PTK7-specific binding molecule comprises a T366Y substitution. In one embodiment of the recombinant fusion protein dimer, the first recombinant fusion protein comprises any one of SEQ ID NO: 148, 167, 188, 189, 191, 192,, 197 to 199, 203 to 205, 259 to 264, 302 to 307, 315 to 320, 327 to 332, 550 to 555, and 568 to 573 and the second recombinant fusion protein comprises any one of SEQ ID NOs: 500 to 508, 518 to 520, 524 to 526, 533 to 536, 540 to 544 . In one embodiment of the recombinant fusion protein dimer, the first recombinant fusion protein comprises any one of SEQ ID NO: 146, 147, 165, 166, 190, 193 to 196, 200 to 202, 253 to 258, 297 to 301, 308 to 314, 321 to 326, and 556 to 567 and the second recombinant fusion protein comprises any one of SEQ ID NOs: 509 to 517, 521 to 523, 527 to 532, 537 to 539, and 545 to 547. In one embodiment of the recombinant fusion protein dimer, the first recombinant fusion protein comprises any one of SEQ ID NO: 148, 191, 192, 197 to 199, and 302 to 307 and the second recombinant fusion protein comprises any one of SEQ ID NOs: 500 to 502, and 524 to 526. In one embodiment of the recombinant fusion protein dimer, the first recombinant fusion protein comprises any one of SEQ ID NO: 146, 147, 193 to 196, 297 to 301, and 308 and the second recombinant fusion protein comprises any one of SEQ ID NOs: 509 to 511, and 527 to 529. In one embodiment of the recombinant fusion protein dimer, the first recombinant fusion protein comprises any one of SEQ ID NO: 327 to 332, and 550 to 555 and the second recombinant fusion protein comprises any one of SEQ ID NOs: 503 to 505, and 534 to 536. In one embodiment of the recombinant fusion protein dimer, the first recombinant fusion protein comprises any one of SEQ ID NO: 321 to 326, and 556 to 561 and the second recombinant fusion protein comprises any one of SEQ ID NOs: 512 to 514, and 537 to 539. In one embodiment of the recombinant fusion protein dimer, the first recombinant fusion protein comprises any one of SEQ ID NO: 259 to 264, and 315 to 320 and the second recombinant fusion protein comprises any one of SEQ ID NOs: 506 to 508, and 533, 540 and 541. In one embodiment of the recombinant fusion protein dimer, the first recombinant fusion protein comprises any one of SEQ ID NO: 253 to 258, and 309 to 314 and the second recombinant fusion protein comprises any one of SEQ ID NOs: 515 to 517, and 530 to 532. In alternatives, the recombinant fusion protein dimers described above may comprise any other ROR1- specific binding molecule described herein in place of P3A1. In alternatives, the recombinant fusion protein dimers described above may comprise any other PTK7- specific binding molecule described herein in place of P2A7, 4D2, or E02. In a second configuration, the invention provides a recombinant fusion protein dimer comprising (a) a first recombinant fusion protein, wherein the first recombinant fusion protein comprises a first PTK7-specific binding protein as disclosed in relation to any of the aspects of the invention and wherein the first antigen binding molecule is fused to a first fragment of an immunoglobulin Fc region engineered to dimerize with a second fragment of an immunoglobulin Fc region, and (b) a second recombinant fusion protein, wherein the second recombinant fusion protein comprises a second PTK7-specific binding protein as disclosed in relation to any of the aspects of the invention fused to a second fragment of an immunoglobulin Fc region engineered to dimerize with the first fragment of an immunoglobulin Fc region. Typically, the first PTK7-specific binding protein will comprise a different sequence to the second PTK7-specific binding protein. The recombinant fusion protein dimer of the second or third configuration may be a bi-paratopic recombinant fusion protein dimer. For example, the recombinant fusion protein dimer of the second or third configuration may be a bi-paratopic fusion protein dimer comprising P2A7-hFc and 4D2 -hFc, wherein the first and second fragment of an immunoglobulin Fc region are engineered to dimerise, for example by knobs-in-holes (KIH) dimerization. The first and/or second recombinant fusion protein may comprise a PTK7 specific antigen binding molecule, such as P2A7, 4D2, or E02, fused to an Fc heavy chain, optionally via a [G4S]x linker. The first fragment of an immunoglobulin Fc region may be a first Fc heavy chain. The second fragment of an immunoglobulin Fc region may be a second Fc heavy chain. One or more residues of the second Fc heavy chain may comprise one or more amino acid substitution suitable for knobs-in-holes (KIH) dimerization with the first Fc heavy chain comprising one or more corresponding amino acid substitutions suitable for knobs-in-holes (KIH) dimerization with the second Fc heavy chain. The one or more amino acid substitution may be selected from the group consisting of T366Y and Y407T. The first Fc heavy chain may comprise a S239C and/or a S442C mutation. The second Fc heavy chain may comprise a S239C and/or a S442C mutation. In one embodiment: (a) the first recombinant fusion protein comprises P2A7, and (b) the second recombinant fusion protein comprises 4D2. In one embodiment: (a) the first recombinant fusion protein comprises P2A7-hFc, and (b) the second recombinant fusion protein comprises 4D2-hFc. In one embodiment: (a) the first recombinant fusion protein comprises P2A7-hFc (S239C), and (b) the second recombinant fusion protein comprises 4D2-hFc (S239C). In one embodiment: (a) the first recombinant fusion protein comprises P2A7-hFc (S442C), and (b) the second recombinant fusion protein comprises 4D2-hFc (S442C). In one embodiment: (a) the first recombinant fusion protein comprises P2A7-hFc (S239C & S442C), and (b) the second recombinant fusion protein comprises 4D2-hFc (S239C & S442C). In one embodiment: (a) the first recombinant fusion protein comprises P2A7-hFc (T366Y), and (b) the second recombinant fusion protein comprises 4D2-hFc (Y407T). In one embodiment: (a) the first recombinant fusion protein comprises P2A7-hFc (S239C & T366Y), and (b) the second recombinant fusion protein comprises 4D2-hFc (S239C & Y407T). In one embodiment: (a) the first recombinant fusion protein comprises P2A7-hFc (S442C & T366Y), and (b) the second recombinant fusion protein comprises 4D2-hFc (S442C & Y407T). In one embodiment: (a) the first recombinant fusion protein comprises P2A7-hFc (S239C & S442C & T366Y), and (b) the second recombinant fusion protein comprises 4D2-hFc (S239C & S442C & Y407T). In one embodiment: (a) the first recombinant fusion protein comprises P2A7-hFc (Y407T), and (b) the second recombinant fusion protein comprises 4D2-hFc (T366Y). In one embodiment: (a) the first recombinant fusion protein comprises P2A7-hFc (S239C & Y407T), and (b) the second recombinant fusion protein comprises 4D2-hFc (S239C & T366Y). In one embodiment: (a) the first recombinant fusion protein comprises P2A7-hFc (S442C & Y407T), and (b) the second recombinant fusion protein comprises 4D2-hFc (S442C & T366Y). In one embodiment: (a) the first recombinant fusion protein comprises P2A7-hFc (S239C & S442C & Y407T), and (b) the second recombinant fusion protein comprises 4D2-hFc (S239C & S442C & T366Y). In alternatives, the recombinant fusion protein dimers described above may comprise any other PTK7- specific binding molecule described herein in place of P2A7 and/or 4D2. In a third configuration, the invention provides a recombinant fusion protein dimer comprising: (a) a first recombinant fusion protein, wherein the first recombinant fusion protein comprises a receptor tyrosine kinase-like orphan receptor 1 (ROR1) specific antigen binding molecule, and (b) a second recombinant fusion protein, wherein the second recombinant fusion protein comprises a protein tyrosine kinase 7 (PTK7) specific antigen binding molecule. The ROR1 specific antigen binding molecule may comprise the amino acid sequence of any ROR1 specific binding molecule, for example any of those disclosed herein. The ROR1 specific antigen binding molecule may comprise any CDR1 and/or CDR3 sequence of any ROR1 specific antigen binding molecule disclosed herein. The ROR1 specific antigen binding molecule may comprise any HV2 and/or HV4 sequence of any ROR1 specific antigen binding molecule disclosed herein. The ROR1 specific antigen binding molecule may comprise any FW1, FW2, FW3a, FW3b and/or FW4 sequence of any ROR1 specific antigen binding molecule disclosed herein. The ROR1 specific antigen binding molecule may have the characteristics of any ROR1 specific antigen binding molecule disclosed herein. The PTK7 specific antigen binding molecule may comprise the amino acid sequence of any PTK7 specific binding molecule, for example any of those disclosed herein. The PTK7 specific antigen binding molecule may comprise any CDR1 and/or CDR3 sequence of any PTK7 specific antigen binding molecule disclosed herein. The PTK7 specific antigen binding molecule may comprise any HV2 and/or HV4 sequence of any PTK7 specific antigen binding molecule disclosed herein. The PTK7 specific antigen binding molecule may comprise any FW1, FW2, FW3a, FW3b and/or FW4 sequence of any PTK7 specific antigen binding molecule disclosed herein. The PTK7 specific antigen binding molecule may have the characteristics of any PTK7 specific antigen binding molecule disclosed herein. According to a sixth aspect, the invention provides a ROR1-specific chimeric antigen receptor (CAR), comprising at least one bi-specific antigen binding molecule as defined by the first or second aspects of the invention, at least one recombinant fusion protein as defined by the third aspect of the invention, or at least one recombinant fusion protein dimer as defined by the fourth or fifth aspects of the invention, at least one PTK7 specific binding molecule as defined by the first configuration, or at least one recombinant fusion protein dimer as defined in the second or third configurations, fused or conjugated to at least one transmembrane region and at least one intracellular domain. The present invention also provides a cell comprising a chimeric antigen receptor according to the sixth aspect, which cell is preferably an engineered T-cell. In a seventh aspect of the invention, there is provided a nucleic acid sequence comprising a polynucleotide sequence that encodes a PTK7-specific binding molecule of the first configuration of the invention, or a bi-specific antigen binding molecule, recombinant fusion protein, recombinant fusion protein dimer or chimeric antigen receptor according to the first, second, third, fourth, fifth or sixth aspects of the invention, the PTK7 specific binding molecule of the first configuration, or the recombinant fusion protein dimer of the second or third configuration. There is also provided a vector comprising a nucleic acid sequence in accordance with the seventh aspect and a host cell comprising such a nucleic acid. A method for preparing a PTK7-specific binding molecule of the first configuration of the invention, the recombinant fusion protein dimer of the second or third configuration, or a bi-specific antigen binding molecule, recombinant fusion protein, recombinant fusion protein dimer or chimeric antigen receptor, of the first, second, third, fourth, fifth, or sixth aspect is provided, the method comprising cultivating or maintaining a host cell comprising the polynucleotide or vector described above under conditions such that said host cell produces the bi-specific antigen binding molecule, recombinant fusion protein or chimeric antigen receptor, optionally further comprising isolating the specific antigen binding molecule, recombinant fusion protein or chimeric antigen receptor. In an eighth aspect of the invention, there is provided a pharmaceutical composition comprising a PTK7-specific binding molecule of the first configuration of the invention, the recombinant fusion protein dimer of the second or third configuration, or the bi-specific antigen binding molecule, fusion protein, recombinant fusion protein dimer or chimeric antigen receptor of the first, second, third, fourth, fifth or sixth aspects. The pharmaceutical composition may contain a variety of pharmaceutically acceptable carriers. Pharmaceutical compositions of the invention may be for administration by any suitable method known in the art, including but not limited to intravenous, intramuscular, oral, intraperitoneal, or topical administration. In preferred embodiments, the pharmaceutical composition may be prepared in the form of a liquid, gel, powder, tablet, capsule, or foam. The bi-specific antigen binding molecule, recombinant fusion protein or chimeric antigen receptor of the first, second, third, fourth, fifth, or sixth aspects may be for use in therapy. More specifically, the bi- specific antigen binding molecule, recombinant fusion protein, recombinant fusion protein dimer or chimeric antigen receptor of the first, second, third, fourth, fifth, or sixth aspects, the PTK7 specific binding molecule of the first configuration, or the recombinant fusion protein dimer of the second or third configuration may be for use in the treatment of cancer. Preferably, the cancer is a ROR1-positive cancer type and/or an PTK7-positive cancer type. More preferably, the cancer is selected from the group comprising blood cancers such as lymphomas and leukemias, chronic lymphocytic leukaemia (CLL), mantle cell lymphoma (MCL), B-cell acute lymphoblastic leukaemia (B-ALL), marginal zone lymphoma (MZL), non-Hodgkin lymphomas (NHL), acute myeloid leukemia (AML) and solid tumours including neuroblastoma, renal cancer, lung cancer, colon cancer, ovarian cancer, pancreatic cancer, breast cancer, skin cancer, uterine cancer, prostate cancer, thyroid cancer, Head and Neck cancer, bladder cancer, oesophageal cancer, stomach cancer or liver cancer. The cancer may be selected from endometrial cancer and uterine carcinosarcoma. More preferably, the cancer is selected from the group comprising triple negative breast cancer (TNBC), breast adenocarcinoma, ovarian cancer, sarcoma, lung adenocarcinoma, lung squamous cell carcinoma, large cell lung carcinoma, small cell lung carcinoma and pleuromesothelioma, Also provided herein is the use of a bi-specific antigen binding molecule, recombinant fusion protein, recombinant fusion protein dimer or chimeric antigen receptor of the first, second, third, fourth, fifth, or sixth aspects, the PTK7 specific binding molecule of the first configuration, or the recombinant fusion protein dimer of the second or third configuration in the manufacture of a medicament for the treatment of a disease in a patient in need thereof. Furthermore, in accordance with the present invention there is provided a method of treatment of a disease in a patient in need of treatment comprising administration to said patient of a therapeutically effective dosage of a bi-specific antigen binding molecule, recombinant fusion protein, recombinant fusion protein dimer or chimeric antigen receptor of the first, second, third, fourth, fifth, or sixth aspects or a pharmaceutical composition of the sixth aspect, or the PTK7 specific binding molecule of the first configuration, or the recombinant fusion protein dimer of the second or third configuration. Preferably, the cancer is a ROR1-positive cancer type and/or an PTK7-positive cancer type. More preferably, the cancer is selected from the group comprising blood cancers such as lymphomas and leukemias, chronic lymphocytic leukaemia (CLL), mantle cell lymphoma (MCL), B-cell acute lymphoblastic leukaemia (B-ALL), marginal zone lymphoma (MZL), non-Hodgkin lymphomas (NHL), acute myeloid leukemia (AML) and solid tumours including neuroblastoma, renal cancer, lung cancer, colon cancer, ovarian cancer, pancreatic cancer, breast cancer, skin cancer, uterine cancer, prostate cancer, thyroid cancer, Head and Neck cancer, bladder cancer, oesophageal cancer, stomach cancer or liver cancer. The cancer may be selected from endometrial cancer and uterine carcinosarcoma. More preferably, the cancer is selected from the group comprising triple negative breast cancer (TNBC), breast adenocarcinoma, ovarian cancer, sarcoma, lung adenocarcinoma, lung squamous cell carcinoma, large cell lung carcinoma, small cell lung carcinoma and pleural mesothelioma. Also provided herein is a method of assaying for the presence of a target analyte in a sample, comprising the addition of a detectably labelled bi-specific antigen binding molecule, recombinant fusion protein, or recombinant fusion protein dimer, or the PTK7 specific binding molecule of the first configuration, or the recombinant fusion protein dimer of the second or third configuration to the sample and detecting the binding of the molecule to the target analyte. In addition, there is provided herein a method of imaging a site of disease in a subject, comprising administration of a detectably labelled bi-specific antigen binding molecule, recombinant fusion protein, or recombinant fusion protein dimer to a subject or the PTK7 specific binding molecule of the first configuration, or the recombinant fusion protein dimer of the second or third configuration. There is also provided herein a method of diagnosis of a disease or medical condition in a subject comprising administration of a bi-specific antigen binding molecule, recombinant fusion protein, or recombinant fusion protein dimer, or the PTK7 specific binding molecule of the first configuration, or the recombinant fusion protein dimer of the second or third configuration. Also contemplated herein is an antibody, antibody fragment, antigen-binding molecule, bi-specific antigen binding molecule, recombinant fusion protein, or recombinant fusion protein dimer that competes for binding to ROR1 and/or PTK7 with the bi-specific antigen binding molecule, recombinant fusion protein, or recombinant fusion protein dimer. The term "compete" when used in the context of antigen binding proteins (e.g., neutralizing antigen binding proteins or neutralizing antibodies) means competition between antigen binding proteins as determined by an assay in which the antigen binding protein (e.g., antibody or functional fragment thereof) under test prevents or inhibits specific binding of a the antigen binding molecule defined herein (e.g., specific antigen binding molecule of the first aspect) to a common antigen (e.g., ROR1 in the case of the specific antigen binding molecule of the first or second aspect). Also described herein is a kit for diagnosing a subject suffering from cancer, or a pre-disposition thereto, or for providing a prognosis of the subject's condition, the kit comprising detection means for detecting the concentration of one or more antigen present in a sample from a test subject, wherein the detection means comprises a bi-specific antigen binding molecule of the first or second aspect, a recombinant fusion protein or recombinant fusion protein dimer of the third, fourth or fifth aspect, a chimeric antigen receptor of the sixth aspect or a nucleic acid sequence of the seventh aspect, or the PTK7 specific binding molecule of the first configuration, or the recombinant fusion protein dimer of the second or third configuration, each being optionally derivatized, wherein presence of antigen in the sample suggests that the subject suffers from cancer. Preferably the one or more antigen comprises ROR1 protein, more preferably an extracellular domain thereof. Preferably the one or more antigen comprises PTK7 protein. More preferably the one or more antigen comprises ROR1 protein and PTK7 protein. More preferably, the kit is used to identify the presence or absence of ROR1-positive cells and/or PTK7-positive cells in the sample, or determine the concentration thereof in the sample. The kit may also comprise a positive control and/or a negative control against which the assay is compared and/or a label which may be detected. The present invention also provides a method for diagnosing a subject suffering from cancer, or a pre- disposition thereto, or for providing a prognosis of the subject's condition, the method comprising detecting the concentration of antigen present in a sample obtained from a subject, wherein the detection is achieved using a bi-specific antigen binding molecule of the first or second aspect, a recombinant fusion protein or recombinant fusion protein dimer of the third, fourth or fifth aspect, a chimeric antigen receptor of the sixth aspect or a nucleic acid sequence of the seventh aspect or the PTK7 specific binding molecule of the first configuration, or the recombinant fusion protein dimer of the second or third configuration, each being optionally derivatized, and wherein presence of antigen in the sample suggests that the subject suffers from cancer. Also contemplated herein is a method of killing or inhibiting the growth of a cell expressing ROR1 and/or PTK7 in vitro or in a patient, which method comprises administering to the cell a pharmaceutically effective amount or dose of (i) bi-specific antigen binding molecule of the first or second aspect, a recombinant fusion protein or recombinant fusion protein dimer of the third, fourth or fifth aspect, a nucleic acid sequence of the sixth aspect, or the CAR or cell according the seventh aspect, or (ii) of a pharmaceutical composition of the eighth aspect, or (iii) the PTK7 specific binding molecule of the first configuration, or the recombinant fusion protein dimer of the second or third configuration. Preferably, the cell expressing ROR1 and/or PTK7 is a cancer cell. More preferably, the ROR1 is human ROR1 and/or the PTK7 is human PTK7. According to a ninth aspect, the invention provides a bi-specific antigen binding molecule comprising an amino acid sequence represented by the formula (II): X-FW1-CDR1-FW2-HV2-FW3a-HV4-FW3b-CDR3-FW4-Y (II) wherein FW1-CDR1-FW2-HV2-FW3a-HV4-FW3b-CDR3-FW4 is a ROR1-specific antigen binding molecule according to the first or second aspect X and Y are optional amino acid sequences wherein the ROR1-specific antigen binding molecule is conjugated to a second moiety and wherein the bi-specific antigen binding molecule further comprises an PTK7-specific antigen binding molecule. As used herein, the “ROR1-specific antigen binding molecule according to the first or second aspect” refers to any ROR1-specific antigen binding molecule described in connection with the bi-specific antigen binding molecules of the first and/or second aspects of the invention (which comprise a ROR1- specific antigen binding molecule). The ROR1-specific antigen binding molecule may be as described anywhere herein. The PTK7-specific antigen binding molecule may be an PTK7-specific antigen binding molecule according to the first or second aspect. As used herein, the “PTK7-specific antigen binding molecule according to the first or second aspect” refers to any PTK7-specific antigen binding molecule described in connection with the bi-specific antigen binding molecules of the first and/or second aspects of the invention (which comprise an PTK7-specific antigen binding molecule). The PTK7-specific antigen binding molecule may be as described anywhere herein. In certain preferred embodiments, the bi-specific antigen binding molecule according to this aspect of the invention may additionally be conjugated to a third, fourth or fifth moiety. Conjugation of further moieties is also contemplated. In some cases, a third, fourth or fifth moiety may be conjugated to the second moiety. Accordingly, it will be understood that any of the moieties according to this aspect of the invention may have additional moieties conjugated thereto. Description of preferred features of the second moiety as set out below apply to the third, fourth, fifth or higher order moiety mutatis mutandis. Preferably X or Y are individually either absent or selected from the group comprising an immunoglobulin, an immunoglobulin Fc region, a fragment of an immunoglobulin Fc region, an Fc heavy chain, a CH2 region, a CH3 region, an immunoglobulin Fab region, a Fab’, a Fv, a Fv-Fc, a single chain Fv (scFv), scFv-Fc, (scFv)2, a diabody, a triabody, a tetrabody, a bispecific t-cell engager, an intein, a VNAR domain, a single domain antibody (sdAb), a VH domain, a scaffold protein (affibodies, centyrins, darpins etc.), or a toxin including but not limited to Pseudomonas exotoxin PE38, diphtheria toxin. Preferably, the conjugation is via a cysteine residue in the amino acid sequence of the specific antigen binding molecule. The cysteine residue may be anywhere in the sequence, including in optional sequences X or Y (if present). The conjugation may be via a thiol, aminoxy or hydrazinyl moiety incorporated at the N-terminus or C- terminus of the amino acid sequence of the specific antigen binding molecule. Preferably, the second moiety is selected from the group comprising detectable label, dye, toxin, drug, pro-drug, radionuclide or biologically active molecule. More preferably, the second moiety is at least one toxin selected from the group comprising: • Auristatins, • anthracyclines, preferably PNU-derived anthracyclines • maytansinoids, • calicheamicins, • amanitin derivatives, preferably α-amanitin derivatives • tubulysins • duocarmycins • radioisotopes for example alpha-emitting radionuclide, such as 227 Th or 225 Ac • liposomes comprising a toxic payload, • protein toxins • taxanes, • pyrrolbenzodiazepines and dimers thereof • indolinobenzodiazepine pseudodimers • spliceosome inhibitors • CDK11 inhibitors • nicotinamide phosphoribosyltransferase inhibitors (NAMPTi) • Pyridinobenzodiazepines and dimers thereof • Cyclopropapyrroloindole (CPI), cyclopropabenzindole (CBI) or cyclopropathienoindole (CTI) optionally dimers thereof • Irinotecan and their derivatives In other preferred embodiments in accordance with this aspect, the second moiety may be from the group comprising an immunoglobulin, an immunoglobulin Fc region, a fragment of an immunoglobulin Fc region, an Fc heavy chain, a CH2 region, a CH3 region, an immunoglobulin Fab region, a Fab’, a Fv, a Fv-Fc, a single chain Fv (scFv), scFv-Fc, (scFv)2, a diabody, a triabody, a tetrabody, a bispecific t-cell engager, an intein, a VNAR domain, a single domain antibody (sdAb), a VH domain, a scaffold protein (affibodies, centyrins, darpins etc.), or a toxin including but not limited to Pseudomonas exotoxin PE38, diphtheria toxin. In particularly preferred embodiments, the second moiety is a VNAR domain, which may be the same or different to the specific antigen binding molecule according to this aspect. Accordingly, dimers, trimers or higher order multimers of VNAR domains linked by chemical conjugation are explicitly contemplated herein. In such embodiments, each individual VNAR domain may have the same antigen specificity as the other VNAR domains, or they may be different. In accordance with this aspect, the bi-specific antigen binding molecule may comprise, for example, bi- paratopic specific antigen binding molecules as described in relation to the first to fifth aspects fused to further biologically active molecules (including but not limited to molecules for half-life extension, for example BA11) and then further conjugated to a second moiety, including but not limited to cytotoxic payloads In accordance with this aspect, the bi-specific antigen binding molecule may comprise a receptor tyrosine kinase-like orphan receptor 1 (ROR1) specific antigen binding molecule. This may be a ROR1- specific antigen binding molecule of the first or second aspect of the invention. Accordingly, any of the preferred features described in relation to the first, second and third aspects apply mutatis mutandis to the sixth aspect. The bi-specific antigen binding molecule of the ninth aspect may be for use in therapy. More specifically, the bi-specific antigen binding molecule of the ninth aspect may be for use in the treatment of cancer. Preferably, the cancer is a ROR1-positive cancer type and/or an PTK7-positive cancer type. More preferably, the cancer is selected from the group comprising blood cancers such as lymphomas and leukemias, chronic lymphocytic leukaemia (CLL), mantle cell lymphoma (MCL), B-cell acute lymphoblastic leukaemia (B-ALL), marginal zone lymphoma (MZL), non-Hodgkin lymphomas (NHL), acute myeloid leukemia (AML) and solid tumours including neuroblastoma, renal cancer, lung cancer, colon cancer, ovarian cancer, pancreatic cancer, breast cancer, skin cancer, uterine cancer, prostate cancer, thyroid cancer, Head and Neck cancer, bladder cancer, oesophageal cancer, stomach cancer or liver cancer. Also provided herein is the use of a bi-specific antigen binding molecule of the ninth aspect in the manufacture of a medicament for the treatment of a disease in a patient in need thereof. Pharmaceutical compositions comprising the bi-specific antigen binding molecule of the ninth aspect are also provided. The pharmaceutical composition may contain a variety of pharmaceutically acceptable carriers Furthermore, in accordance with the present invention there is provided a method of treatment of a disease in a patient in need of treatment comprising administration to said patient of a therapeutically effective dosage of a bi-specific antigen binding molecule of the ninth aspect or a pharmaceutical composition comprising a bi-specific antigen binding molecule of the ninth aspect. Preferably, the cancer is a ROR1-positive cancer type and/or an PTK7-positive cancer type. More preferably, the cancer is selected from the group comprising blood cancers such as lymphomas and leukemias, chronic lymphocytic leukaemia (CLL), mantle cell lymphoma (MCL), B-cell acute lymphoblastic leukaemia (B-ALL), marginal zone lymphoma (MZL), non-Hodgkin lymphomas (NHL), acute myeloid leukemia (AML) and solid tumours including neuroblastoma, renal cancer, lung cancer, colon cancer, ovarian cancer, pancreatic cancer, breast cancer, skin cancer, uterine cancer, prostate cancer, thyroid cancer, Head and Neck cancer, bladder cancer, oesophageal cancer, stomach cancer or liver cancer. Also provided herein is a method of assaying for the presence of a target analyte in a sample, comprising the addition of a detectably labelled bi-specific antigen binding molecule of the ninth aspect to the sample and detecting the binding of the molecule to the target analyte. In addition, there is provided herein a method of imaging a site of disease in a subject, comprising administration of a detectably labelled bi-specific antigen binding molecule of the ninth aspect to a subject. There is also provided herein a method of diagnosis of a disease or medical condition in a subject comprising administration of a bi-specific antigen binding molecule of the ninth aspect. Furthermore, any of the features described in respect of any of the above-mentioned aspects of the invention may be combined mutatis mutandis with the other aspects of the invention. In addition to the sequences mentioned the following sequences are expressly disclosed. Certain of these sequences relate to examples of molecules of the invention described herein:

Y T _{L E} ^S _T ^P _E D ^A _F ^D _E ^P _E M Y ^{M P T S} T _T ^P _E D ^A _F ^D _E ^P _{E Y} ^{S M} _T ^P _E D ^A _F ^D _E K W ^P _E S C _{K E} ^P _E C _K ^P _E C S ^P _V Q _Y ^Q _S N ^Q _S N ^{D D} _V Q ^S _S ^Q _S N ^Q _S N _V Q ^{S Q} _S N A _A ^L S ^G _E ^{V G C P} _L N ^K _{L L} N ^L _E ^{V G C P} _L N ^{K L} _E ^V _Y C ^P _L R _A ^A _V e _c ^P G _S ^P _{P K A} ^{S K W} _E ^T _L ^R _{V I} ^{A P} _{P K} ^{K W} _E ^A _V ^G _{P K} ^K S W ^V _A D _{L P} ^K _S ^Y _{S S} D ^R _{S A} ^S _A D _{L P} ^K _{S S} ^P _A ^S _A D _L T ^S _L R Q D _L ^V _S D ^S _L R Q D ^V _S D ^S _L R n _e Q ^{P L} N _P ^H M L C ^{K D} _K ^R _S ^L N ^T _P ^H M C ^{K L} N ^T _P ^H M u ^T _{Y E} ^K _F ^P _{P S I} Q _S ^N _E ^K _F ^P _S ^L _I Q _{S E} ^K _F ^P _S ^L _{I q V} ^A _K ^T _E ^S _T ^M _P R D _L ^G _Y ^T _{E P} ^S _T ^M _P R D ^T _{E P} ^S _T ^{M e S} W ^G G N ^{G C E I} W Q R ^G G N ^{G C} W _{P S A} C Q R _{F S A S T F S A} Q R ^G _F G N s _e c _i ^{s g} I ^c n _e H e ^- _{( i} ^s _{F u} ^m _{a 1 1} H - ^- ₁ R q _e ⁿ R R ₁ R O s _l ^e O O c R R O R a _n ⁿ _{e 5} ^{) n} _n ^R a ₎ ⁿ _a ⁱ _a ^e ₎ ⁿ ₎ o ⁱ _t ^{u i} _q ^{1 e} _V O _s O _a O 1 m m m ^u m u H C ^{u o} _o H u H d _{S B h ( h d} m ^{C C d} _{( h ( a –} ^D _{I 3 e} ^l _b Q _: O _{5 1 2 3 4} a ^E T _S N ¹ ₁ ⁵ ₁ ⁵ ₁ ⁵ ₁ ⁵ ₁ P _E ^N G ^G _P ^L R D ^{A A H} G ^{D P} _A N ^S R _E ^{A D P} _{E Y} ^{M D} _{V S} N _P ^P _E D _{F E P} G _E ^P N _T ^P _E D _{F E Y} ^{M Q} _K ^V _K ^{S S} _L G ^{Q Q C} H G H _L ^{E P} _V C Q ^{S Q} N ^Q _{K S} N ^V _V Q C _E ^{S L} _{F S K} Q G ^{S A} _{P K} ^{L V} _{S S} P _S N N ^K _E ^C W _{L P} ^V _V N C ^P _L ^L _{V K} Q ^G _{E V} ^{G C} _L N ^{K W} _T ^K _Y ^{E S} _K D ^P H Q _A ^M _K ^{D N} G _P ^{A P} _{P K} ^{K W} _E e _P ^K c Q _S ^V _E ^E _{K V} ^N _A N D ^Q _L ^W _{V S} N ^S _{S A} ^S D _{L P} ^{K A} Q _P D ^{P S} R _P ^S _{S S} ^{V V S} _L ^V D _A ^S _L R Q n C D ^P G _I ^T _Y ^D N _{S L} Q _{V K E} ^S _{L S} N ^T _P M C D e u Q ^K _{S T} D _L H ^H _T M C D C C W ^L _E ^{K H L} _I Q ^K _{S q} R D R ^{N S} _L ^S H ^{V K} _L ^{T L} _{I I} Q R ^{T K E S} _{K F} ^P _{P S} R W _P N _{E P} ^S _T ^L _P H ^P _{S V Y V} ^T _E ^S _T ^M _P D e _S ^G _S ^C _A M D ^Y _F ^H _L ^V _E W R ^G _L G N G C ^E _P ^E _K ^A _I ^Q _T W Q R ^G _F G N ^G _S ^C _{A e} ^c _F ^{c -} _F m ₂ - _{1 a} R R n O O e _c R R n _e ⁿ _{a )} ^e ₎ u _q O _s O m ^{u e} _S ^u H _o H h ^C ₍ m ^C ₍ D _I Q _: E _S O _{5 6} N ⁵ ₁ ⁵ ₁

K ^Y _{K V} ^T _I ^{G V} _{T L} N _P ^{C K Y} _{K A} ^S N _T D _{T A V} ^S N Q _Y D R ^I _P N Q _Y H _V ^P _E ^L N F M ^T N R P ^D R H N C ^{T P L E F} _F P _T G V ^R _{P S E} ^D _L ^I _{K A} ^H F ^{P Y} _{K V E} ^F V M _S ^{D E R} _{P S} G Q G ^D _L N ^R _A ^{S P} _I H _{S V} G Q G 1 D ^D _S ^{T R} _I C _S ^G _I G G G D ^D _S ³ ₁ V ^G Y _K A D _L ^{R A} _I ^{T R} _I G ^G N G ^V _K D K ^{L Y} _{S L E} G D C ^{L G} _Y ^A _K ^L W N _F ^S _V ^R I ^{P D} _S R ^{C N} _{E S} W ^S _{V I} ^{P T} _{P K} ^{G Y} _{P Y A} ^P G A _F ^N _F ^T _P K _{K V} ^{T E} _T ^D _{I Y} Q ^P _{F E} ^R G G ^K _K ^T _T E _{I P} ^{P K E} N _{L S} ^{T C A P A G} _V ^E _I ^K A _Y ^S _{A F Y S} H _{T S} ^E _P ^P _{A Y} D ^P N _T N ^R _F G ^E D C _P ^F _S G ^{D P} N E _L N ^L Q G _{E L} N H ^{E S} _I ^E _S ^H G ^{E S A} _{K P K} ^W _S R _E ^P _{L T} H ^A _{K P K V} ^N Q ^{G S} R ^{Y P} _I ^D H ^G _E ^S _V ^N Q ^{G D} _S G _{P T} ^P _E D ^A _{F E} ^P _Y ^{M D} _S G _{P V} V ^V N ^S _L ^P _{V E V K} ^{S S Q} C ^Q _{K V} ^V N ^S _L C _E ^S Q _{S S} N _S N ^V _{V K} ^S _E ^{S C K} W _L ^L _E ^V _V ^{G C P} _L N ^K C W _{L T Y} ^{E S} c _{E K V K} ^A _S ^P _{P K A} ^S D ^K _L ^W _E ^C P ^K _T ^K _Y ^{E S} _K e ^{V E A} _I Q ^V D _A ^S _{S L} R Q ^{V E} _V D _{E K} ^A _I Q n _e ^P _T G D ^T _{Y S} N ^T _P M C ^{K P} G D ^T _Y u _q R ^{N L H} L ^S _P H _E ^K N ^T _F ^P _{P S} ^L _I Q _{S T} ^N H S ^M R D R _L ^S _P N e ^S _{I S} W M D ^Y _F ^H _{E L} W Q R ^G _{T P F} G N ^G _S ^{C S} _{I A} W M D ^Y _F ^H _{L e} ^c _F - ^m _{1 a} R n O e _c R n _{e )} u _q O e _t H S ^a _r ^C ₍ D _I Q _: E _S O ₇ N ⁵ ₁ A highly interesting class of DNA intercalating toxins for use as payloads for drug conjugates are anthracyclines, because of their proven clinical validation as chemotherapeutic drugs in cancer therapy. Stability of chemically-conjugated protein drug conjugates is an important consideration, since unintended release of a highly potent anthracycline toxin, like PNU-159682, in the circulation of a patient prior to targeting of the tumour cells would lead to off target effects and undesirable side effects. Some example molecules released from PNU conjugates include release of PNU159682 derivative from different Val-Cit-PAB containing drug linkers. Potent toxins that can be linked to targeting proteins with high stability are therefore required in order to avoid, or at least reduce, unwanted side effects. Alternatively, linker payloads are designed such that extracellular cleavage releases derivatives of the payload with attenuated potency. However, sufficient potency needs to be retained in order to avoid any reduction in side effect being negated due to the need to administer higher doses to achieve efficacy. Ease of conjugation is an important factor in producing easily manufacturable products. Payloads of the present disclosure may use a maleimide group, which can react to any available thiol group on a conjugation partner using straightforward and standard conditions. Furthermore, the use of maleimide/thiol chemistry for conjugation allows for site-specific conjugation to introduced thiol groups, for example on the side-chain of an engineered cysteine residue in a protein sequence. In some cases described herein, a cysteine may be introduced via the introduction of his-myc tag containing an engineered cysteine (example sequences include, but are not limited to, QACKAHHHHHHGAEFEQKLISEEDL (SEQ ID NO: 97) or QACGAHHHHHHGAEFEQKLISEEDL (SEQ ID NO: 99)) at the C- or N-terminal of a protein. Antibody / protein drug conjugates generated using non-selective labelling methods, such as through reaction with amino functionalities within proteins, deliver products containing multiple different species with differing drug to antibody ratios. This impacts the properties of the conjugate including potency and PK properties which impacts in vivo efficacy and toxicities. Therefore, thiol reactive payloads are of great importance, as these can be reacted in high yield, in a simple process, with naturally occurring cysteine residues in proteins or with a cysteine residue engineered into a specific site at any point within the sequence of proteins using molecular biology / recombinant protein expression or chemical synthesis or through chemical modification of expressed, synthetic or natural proteins. In some cases described herein, the cysteine is engineered into the Fc region of an Fc fusion protein. The present disclosure provides anthracycline (PNU) derivatives suitable for use in drug conjugates. Specifically, derivatives of PNU159682 are provided, which lack the C14 carbon and attached hydroxyl functionality, and are functionalised with an ethylenediamino (EDA) group at the C13 carbonyl of PNU159682. This EDA-PNU159682 can in turn be functionalised, through the amino group of the EDA moiety, with a maleimide containing linker. A maleimide group is present in the anthracycline (PNU) derivatives of formula (V) and may also be present in the anthracycline (PNU) derivatives of formula (VI). Such payloads are able to react with a free thiol group on another molecule. Where the free thiol is on a protein, a protein-drug conjugate (PDC) may be formed. Surprisingly, derivatives of PNU159682 functionalised with an ethylenediamino (EDA) group and linked to a thiol group via a maleimide group show higher stability compared to non-EDA payloads or liberated payload derivatives with slightly less potency. More stable payloads may be advantageous because of reduced off-target effects, which in turn may lead to reduced side effects and increased patient compliance. WO 2020/254640 describes anthracycline (PNU) derivatives of formula (V): wherein [X] is an optional spacer selected from the group comprising substituted or unsubstituted alkyl groups, substituted or unsubstituted heteroalkyl groups, substituted or unsubstituted aryl groups, substituted or unsubstituted heteroaryl groups, one or more heteroatoms, polyethylene glycol, or a combination thereof; [L1] and [L2] are optional linkers selected from the group consisting of valine (Val), citrulline (Cit), alanine (Ala), asparagine (Asn), a peptide, -(CH2)n-, -(CH2CH2O)n-, p-aminobenzyloxycarbonyl (PAB), Val-Cit- PAB, Val-Ala-PAB, Ala-Ala-Asn-PAB, Val-Ala, Asn-Ala, any amino acid except glycine, and combinations thereof. The anthracycline (PNU) derivative of formula (V) may comprise [L1], [L2] or [L1] and [L2]. Preferably, where [L1] and/or [L2] are peptides, said peptides do not contain glycine. It will be clear to those of skill in the art that when optional spacers and/or optional linkers are absent a bond remains in their place. Preferably, [X] is selected from the group comprising polyethylene glycol, ’ , wherein represents the point of attachment to the rest of the molecule and wherein [R] is an optional spacer selected from the group comprising substituted or unsubstituted alkyl groups, substituted or unsubstituted heteroalkyl groups, substituted or unsubstituted aryl groups, substituted or unsubstituted heteroaryl groups, one or more heteroatoms, polyethylene glycol, or a combination thereof. Most preferably, [X] is polyethylene glycol. The polyethylene glycol may be PEG4. Preferably, [L2] is p-aminobenzyloxycarbonyl (PAB) or Alanine. Preferably, the anthracycline (PNU) derivative comprises [L1] and/or [L2] and [X] is optional. Accordingly, [L1] and/or [L2] may be linkers selected from the group consisting of valine (Val), citrulline (Cit), alanine (Ala), asparagine (Asn), a peptide, -(CH ₂ ) _n -, -(CH ₂ CH ₂ O) _n -, p-aminobenzyloxycarbonyl (PAB), Val-Cit-PAB, Val-Ala-PAB, Ala-Ala-Asn-PAB, Val-Ala, Asn-Ala, any amino acid except glycine, and combinations thereof. The anthracycline (PNU) derivative of formula (V) may comprise [L1], [L2] or [L1] and [L2]. The anthracycline (PNU) derivative of formula (V) may comprise [L1] and/or [L2]. WO 2020/254640 describes anthracycline (PNU) derivatives of formula (V): wherein [X] is an optional spacer selected from the group comprising substituted or unsubstituted alkyl groups, substituted or unsubstituted heteroalkyl groups, substituted or unsubstituted aryl groups, substituted or unsubstituted heteroaryl groups, one or more heteroatoms, polyethylene glycol, or a combination thereof; [L1] and/or [L2] are linkers selected from the group consisting of valine (Val), citrulline (Cit), alanine (Ala), asparagine (Asn), a peptide, -(CH2)n-, -(CH2CH2O)n-, p-aminobenzyloxycarbonyl (PAB), Val-Cit- PAB, Val-Ala-PAB, Ala-Ala-Asn-PAB, Val-Ala, Asn-Ala, any amino acid except glycine, and combinations thereof; wherein the anthracycline (PNU) derivative of formula (V) comprises [L1], [L2] or Preferably, [X] is selected from the group comprising polyethylene glycol, represents the point of attachment to the rest of the molecule and wherein [R] is an optional spacer selected from the group comprising substituted or unsubstituted alkyl groups, substituted or unsubstituted heteroalkyl groups, substituted or unsubstituted aryl groups, substituted or unsubstituted heteroaryl groups, one or more heteroatoms, polyethylene glycol, or a combination thereof. Most preferably, [X] is polyethylene glycol. The polyethylene glycol may be PEG4. Preferably, [L2] is p-aminobenzyloxycarbonyl (PAB) or Alanine. Preferably, the PNU derivative has a structure selected from:

5 WO 2020/254640 also describes anthracycline (PNU) derivatives of formula (VI):

wherein [X] is an optional spacer selected from the group comprising substituted or unsubstituted alkyl groups, substituted or unsubstituted heteroalkyl groups, substituted or unsubstituted aryl groups, substituted or unsubstituted heteroaryl groups, one or more heteroatoms, polyethylene glycol, or a combination thereof; wherein [Z] is a reactive group. The reactive group may be any reactive group suitable for use in a conjugation reaction, particularly a conjugation reaction to a target binding molecule. [Z] may therefore be a moiety comprising a functional group for use in bioconjugation reactions. Functional groups for use in bioconjugation reactions include but are not limited to, ^ maleimides or alkyl halides for reaction with thiol groups or selenol groups on proteins through thioether and selonoether reactions; ^ sulphydryl groups for reaction with maleimide, alkyl halide or thiol functionalised molecules including the thiol groups of protein cysteine residues; ^ activated disulphides such as pyridyl dithiols (Npys thiols) or TNB thiols (5-thiol-2-nitrobenzoic acid) for reaction with thiol groups to form disulphide linkages through thiol disulphide exchange; ^ amino groups for attachment to carboxyl groups on proteins and biomolecules through amide bond forming reactions; ^ alkyne groups, particularly ring constrained alkynes such as dibenzocyclooctyne (DBCO) or bicyclo[6.1.0]nonyne (BCN) for the reaction with azido functionalised biomolecules through strain promoted alkyne-azide cycloaddition copper free chemistry. Azido functionalities can be introduced into proteins through, for example, the incorporation of the unnatural amino acid para-azidomethy-L-phenyalanine or into protein glycans using enzyme mediated glycoengineering to attach azido-containing sugar analogues; ^ azido groups for reaction with alkyne functionalised target-binding molecule through strain promoted alkyne-azide cycloaddition copper free chemistry; ^ aminoxy groups for reactions with aldehyde and ketone groups on biomolecules through oxime forming ligations. Ketones can be introduced into proteins through the use of amber stop codon technologies such as the incorporation of the non-natural amino acid, para-acetyl phenylalanine. Aldehydes can be found on biomolecules through the presence of reducing sugars and can be introduced into proteins through periodate oxidation of N-terminal serine residues or periodate oxidation of cis-glycol groups of carbohydrates. Aldehyde groups can also be incorporated into proteins through the conversion of protein cysteines, within specific sequences, to formyl glycine by formylglycine generating enzyme. In addition formylglycine containing proteins have been conjugation to payloads via the Hydrazino-Pictet-Spengler (HIPS) ligation; ^ aldehyde or ketone groups for the reaction with aminoxy or hydrazide or hydrazinyl functionalized biomolecules through oxime or hydrazine bond forming ligation reactions. Protein aminoxy and hydrazide functionalized proteins can be generated through cleavage of intein- fusion proteins. [Z] may therefore be selected from the group consisting of a maleimide, an alkyl halide, a sulphydryl group, an activated disulphide (such as pyridyl dithiols (Npys thiols) or TNB thiols (5-thiol-2-nitrobenzoic acid)), an amino group, an alkyne group (such as ring constrained alkynes such as dibenzocyclooctyne (DBCO) or bicyclo[6.1.0]nonyne (BCN)), an azido group, an aminoxy group, an aldehyde group and a ketone group. [Z] may also be a moiety for enzyme mediated bioconjugation reactions. Moieties for use in enzyme mediated conjugation reactions include but are not limited to polyGly [ (Gly)n] for use in sortase-enzyme mediated antibody conjugation or an appropriate primary amine for bacterial transglutaminase mediated conjugation to glutamine γ-carboxyamide groups contained with sequences such as Lys-Lys-Gln-Gly and Lys-Pro-Glu-Thr-Gly. [Z] may therefore be selected from the group consisting of polyGly and a primary amine. The PNU derivative according to formula (VI) may therefore correspond to a PNU derivative of formula (V) wherein L1 is Val-Cit-PAB, L2 is absent and wherein the maleimide group may be replaced with another Reactive Group as defined above. Preferably, [X] is selected from the group comprising polyethylene glycol, ’ , wherein represents the point of attachment to the rest of the molecule and wherein [R] is an optional spacer selected from the group comprising substituted or unsubstituted alkyl groups, substituted or unsubstituted heteroalkyl groups, substituted or unsubstituted aryl groups, substituted or unsubstituted heteroaryl groups, one or more heteroatoms, polyethylene glycol, or a combination thereof. Most preferably, [X] is polyethylene glycol. The polyethylene glycol may be PEG4. The PNU derivative according to formula (V) or formula (VI) may be conjugated to a ROR1 specific antigen binding molecule according to the present invention or to a recombinant fusion protein or recombinant fusion protein dimer of the invention. According to a tenth aspect, the invention provides a target-binding molecule-drug conjugate, comprising (a) a PTK7-specific binding molecule of the first configuration of the invention, or a bi- specific antigen binding molecule according to the first, second or ninth aspect, or a recombinant fusion protein of the third aspect or a recombinant fusion protein dimer of the fourth or fifth aspect or the second or third configuration, and (b) at least one toxin. The at least one toxin may be any toxin suitable for use as a payload. For example, the toxin may be a topoisomerase inhibitor, a microtubule inhibitor or a DNA-targeting agent. The topoisomerase inhibitor may be a topoisomerase I inhibitor or a topoisomerase II inhibitor. The topoisomerase I or II inhibitor may be an anthracycline. For example, the anthracycline may be Doxorubicin, Daunorubicin, Epirubicin, or Idarubicin. The anthracycline may be a PNU-derived anthracycline such as PNU-159682 or a derivative thereof. The Topoisomerase I inhibitor may be a PNU-derived anthracycline such as PNU-159682 or a derivative thereof. The Topoisomerase I inhibitor may be an exatecan for example deruxtecan The microtubule inhibitor may be a taxane, a vinca alkaloid or an epothilone. For example, the microtubule inhibitor may be eribulin, paclitaxel, docetaxel or ixbepilone. The microtubule inhibitor may be an auristatin, a maytansinoid or a tubulysin. The DNA-targeting agent may for example be a calicheamicin, a duocarmycin, a pyrrolobenzodiazepine, an indolino-benzodiazepene, a cyclopropylpyrroloindole or a thienoindole The at least one toxin may be one or more toxin selected from the group consisting of: • auristatins, • anthracyclines, preferably PNU-derived anthracyclines • maytansinoids, • amanitin derivatives, preferably ^-amanitin derivatives • calicheamicins, • tubulysins • duocarmycins • radioisotopes - such as an alpha-emitting radionuclide, such as 227 Th and 225 Ac label • liposomes comprising a toxic payload, • protein toxins • taxanes • pyrrolbenzodiazepines and dimers thereof • indolinobenzodiazepine pseudodimers • spliceosome inhibitors • CDK11 inhibitors • nicotinamide phosphoribosyltransferase inhibitors (NAMPTi) • Pyridinobenzodiazepines and dimers thereof • Cyclopropapyrroloindole (CPI), cyclopropabenzindole (CBI) or cyclopropathienoindole (CTI) and optionally dimers thereof • Irinotecan or exatecan and their derivatives. Any of the spacer ([X]) and/or linker ([L1] and/or [L2]) groups described herein in connection with anthracycline toxins are also explicitly contemplated in connection with any other toxin described herein. The toxin may be an auristatin. The auristatin may be Auristatin E (AE) or monomethylauristatin E (MMAE). The auristatin may be an MMAE derivative. Any of the spacer ([X]) and/or linker ([L1] and/or [L2]) groups described herein in connection with anthracycline toxins are also explicitly contemplated in connection with auristatins such as MMAE. In preferred embodiments, the target-binding molecule-drug conjugate may comprise Val-Cit-MMAE (vcMMAE). Wherein the toxin is an auristatin, the target-binding molecule-drug conjugate may comprise the structure of formula (VI): wherein, [X] is an optional spacer selected from the group comprising substituted or unsubstituted alkyl groups, substituted or unsubstituted heteroalkyl groups, substituted or unsubstituted aryl groups, substituted or unsubstituted heteroaryl groups, one or more heteroatoms, polyethylene glycol, or a combination thereof; [L1] and [L2] are optional linkers selected from the group consisting of valine (Val), citrulline (Cit), alanine (Ala), asparagine (Asn), a peptide, -(CH2)n-, -(CH2CH2O)n-, p-aminobenzyloxycarbonyl (PAB), Val-Cit- PAB, Val-Ala-PAB, Ala-Ala-Asn-PAB, Val-Ala, Asn-Ala, any amino acid except glycine, and combinations thereof; and Y comprises a bi-specific antigen binding molecule according to the first, second or ninth aspect, or a recombinant fusion protein of the third aspect or a recombinant fusion protein dimer of the fourth or fifth aspect. Wherein the toxin is an auristatin, the target-binding molecule-drug conjugate may comprise the structure of formula (VIII): wherein, Y comprises a bi-specific antigen binding molecule according to the first, second or ninth aspect, or a recombinant fusion protein of the third aspect or a recombinant fusion protein dimer of the fourth or fifth aspect. The toxin may be a nicotinamide phosphoribosyltransferase (NAMPT) inhibitor (NAMPTi), as described in Bohnke et al Bioconjugate Chem.2022, 33, 6, 1210–1221, hereby incorporated by reference in its entirety. Further instances of toxins and corresponding target-binding molecule-drug conjugates, conjugated via a cysteine residue of a bi-specific antigen binding molecule according to the first, second or ninth aspect, or a recombinant fusion protein or recombinant fusion protein of the third aspect or a recombinant fusion protein dimer of the fourth or fifth aspect may be selected from the following:

Wherein the toxin is a PNU-derived anthracycline, the target-binding molecule-drug conjugate may comprise (b) an anthracycline (PNU) derivative, wherein the target-binding molecule-drug conjugate has the structure of formula (III): wherein [X] is an optional spacer selected from the group comprising substituted or unsubstituted alkyl groups, substituted or unsubstituted heteroalkyl groups, substituted or unsubstituted aryl groups, substituted or unsubstituted heteroaryl groups, one or more heteroatoms, polyethylene glycol, or a combination thereof; [L1] and [L2] are optional linkers selected from the group consisting of valine (Val), citrulline (Cit), alanine (Ala), asparagine (Asn), a peptide, -(CH2)n-, -(CH2CH2O)n-, p-aminobenzyloxycarbonyl (PAB), Val-Cit- PAB, Val-Ala-PAB, Ala-Ala-Asn-PAB, Val-Ala, Asn-Ala, any amino acid except glycine, and combinations thereof; and Y comprises a bi-specific antigen binding molecule according to the first, second or ninth aspect, or a recombinant fusion of the third aspect or a recombinant fusion protein dimer of the fourth or fifth aspect. The target-binding molecule-drug conjugate of formula (III) may comprise [L1], [L2] or [L1] and [L2]. Preferably, target-binding molecule-drug conjugate where [L1] and/or [L2] are peptides, said peptides do not contain glycine. It will be clear to those of skill in the art that when optional spacers and/or optional linkers are absent a bond remains in their place. Preferably, the target-binding molecule-drug conjugate has a structure selected from:

Wherein the toxin is a PNU-derived anthracycline, the target-binding molecule-drug conjugate may comprise: (b) an anthracycline (PNU) derivative, wherein the target-binding molecule-drug conjugate has the structure of formula (IV): wherein [X] is an optional spacer selected from the group comprising substituted or unsubstituted alkyl groups, substituted or unsubstituted heteroalkyl groups, substituted or unsubstituted aryl groups, substituted or unsubstituted heteroaryl groups, one or more heteroatoms, polyethylene glycol, or a combination thereof; [Z] is a linker derived from a reactive group used to conjugate the anthracycline (PNU) derivative and the target-binding molecule; and Y comprises a bi-specific antigen binding molecule according to the first, second or ninth aspect, or a recombinant fusion protein or recombinant fusion protein dimer according to the third, fourth or fifth aspect. [Z] is a typically a moiety derived from a reactive group used to conjugate the anthracycline (PNU) derivative and the target-binding molecule. [Z] may be a moiety derived from a reactive group selected from the group consisting of a maleimide, an alkyl halide, a sulphydryl group, an activated disulphide, an amino group, an alkyne group, an azido group, an aminoxy group, an aldehyde group and a ketone group. [Z] may therefore be selected from the group consisting of a disulphide bond, an amide bond, an oxime bond, a hydrazone bond, a thioether bond, a 1, 2, 3 triazole and polyGly. Preferably, [X] is selected from the group comprising polyethylene glycol, ’ , wherein represents the point of attachment to the rest of the molecule and wherein [R] is an optional spacer selected from the group comprising substituted or unsubstituted alkyl groups, substituted or unsubstituted heteroalkyl groups, substituted or unsubstituted aryl groups, substituted or unsubstituted heteroaryl groups, one or more heteroatoms, polyethylene glycol, or a combination thereof. Most preferably, [X] is polyethylene glycol. The polyethylene glycol may be PEG4. Preferably, the target-binding molecule is a protein or a nucleic acid. Examples of target-binding proteins (which may also be referred to as specific antigen binding proteins) include but are not limited to an immunoglobulin or antibody, an immunoglobulin Fc region, a fragment of an immunoglobulin Fc region, an Fc heavy chain, a CH2 region, a CH3 region, an immunoglobulin Fab region, a Fab’, a Fv, a Fv-Fc, a single chain Fv (scFv), a scFv-Fc, (scFv) ₂ , a diabody, a triabody, a tetrabody, a bispecific t-cell engager, an intein, a VNAR domain, a single domain antibody (sdAb), a VH domain, a scaffold protein (affibodies, centyrins, darpins etc.). Examples of target-binding nucleic acids include but are not limited to aptamers. Preferably, the target-binding molecule-drug conjugate is a protein and the anthracycline (PNU) derivative is conjugated to a thiol-containing amino acid residue in the amino acid sequence of a protein or to a thiol group introduced by chemical modification of the protein, for example incorporated at the N- terminus or C-terminus of the amino acid sequence of the specific antigen binding protein. Thiol groups may also be introduced into other target-binding molecules, such as nucleic acids. In one embodiment of the tenth or eleventh aspect, the target-binding molecule-drug conjugate, Y comprises a bi-specific antigen binding molecule according to the first or second aspects of the invention, conjugated to the PNU derivative via a human immunoglobulin Fc region or fragment thereof. In one embodiment the fragment of the human immunoglobulin Fc region may be selected from the group consisting of an Fc heavy chain, a CH2 region and a CH3 region. Also provided herein is the target-binding molecule-drug conjugate according to the above aspects, for use in therapy. Also provided herein is the target-binding molecule-drug conjugate according to the above aspects, for use in the treatment of cancer. Also provided herein is the use of a target-binding molecule-drug conjugate according to the above aspects in the manufacture of a medicament for the treatment of a disease in a patient in need thereof. Also provided herein is a method of treatment of a disease in a patient in need of treatment comprising administration to said patient of a therapeutically effective dosage of a target-binding molecule-drug conjugate according to the above aspects. The disease may be cancer. Preferably, the cancer is a ROR1-positive cancer type and/or an PTK7-positive cancer type. More preferably, the cancer is selected from the group comprising blood cancers such as lymphomas and leukemias, chronic lymphocytic leukaemia (CLL), mantle cell lymphoma (MCL), B-cell acute lymphoblastic leukaemia (B-ALL), marginal zone lymphoma (MZL), non-Hodgkin lymphomas (NHL), acute myeloid leukemia (AML) and solid tumours including neuroblastoma, renal cancer, lung cancer, colon cancer, ovarian cancer, pancreatic cancer, breast cancer, skin cancer, uterine cancer, prostate cancer, thyroid cancer, Head and Neck cancer, bladder cancer, oesophageal cancer, stomach cancer or liver cancer. The cancer may be mesothelioma or triple negative breast cancer (TNBC). The mesothelioma may be pleural mesothelioma. Also provided herein is a pharmaceutical composition comprising a target-binding molecule-drug conjugate according to any of the above aspects, and at least one other pharmaceutically acceptable ingredient. Definitions An antigen specific binding molecule of the invention comprises amino acid sequence derived from a synthetic library of VNAR molecules, or from libraries derived from the immunization of a cartilaginous fish. The terms VNAR, IgNAR and NAR may be used interchangeably also. Amino acids are represented herein as either a single letter code or as the three letter code or both. The term “affinity purification” means the purification of a molecule based on a specific attraction or binding of the molecule to a chemical or binding partner to form a combination or complex which allows the molecule to be separated from impurities while remaining bound or attracted to the partner moiety. The term “Complementarity Determining Regions” or CDRs (i.e., CDR1 and CDR3) refers to the amino acid residues of a VNAR domain the presence of which are typically involved in antigen binding. Each VNAR typically has two CDR regions identified as CDR1 and CDR3. Additionally, each VNAR domain comprises amino acids from a “hypervariable loop” (HV), which may also be involved in antigen binding. In some instances, a complementarity determining region can include amino acids from both a CDR region and a hypervariable loop. In other instances, antigen binding may only involve residues from a single CDR or HV. According to the generally accepted nomenclature for VNAR molecules, a CDR2 region is not present. “Framework regions” (FW) are those VNAR residues other than the CDR residues. Each VNAR typically has five framework regions identified as FW1, FW2, FW3a, FW3b and FW4. The boundaries between FW, CDR and HV regions in VNARs are not intended to be fixed and accordingly some variation in the lengths and compositions of these regions is to be expected. This will be understood by those skilled in the art, particularly with reference to work that have been carried out in analyzing these regions. (Anderson et al., PLoS ONE (2016) 11 (8); Lui et al., Mol Immun (2014) 59, 194-199; Zielonka et al., Mar Biotechnol (2015).17, (4) 386–392; Fennell et al., J Mol Biol (2010) 400. 155-170; Kovalenko et al., J Biol Chem (2013) 288.17408-17419; Dooley et al., (2006) PNAS 103 (6). 1846-1851). The molecules of the present invention, although defined by reference to FW, CDR and HV regions herein, are not limited to these strict definitions. Variation in line with the understanding in the art as the structure of the VNAR domain is therefore expressly contemplated herein. A “codon set” refers to a set of different nucleotide triplet sequences used to encode desired variant amino acids. A set of oligonucleotides can be synthesized, for example, by solid phase synthesis, including sequences that represent all possible combinations of nucleotide triplets provided by the codon set and that will encode the desired group of amino acids. A standard form of codon designation is that of the IUB code, which is known in the art and described herein. A codon set is typically represented by 3 capital letters in italics, e.g. NNK, NNS, XYZ, DVK etc. A “non- random codon set” therefore refers to a codon set that encodes select amino acids that fulfill partially, preferably completely, the criteria for amino acid selection as described herein. Synthesis of oligonucleotides with selected nucleotide “degeneracy” at certain positions is well known in that art, for example the TRIM approach (Knappek et al.; J. Mol. Biol. (1999), 296, 57-86); Garrard & Henner, Gene (1993), 128, 103). Such sets of oligonucleotides having certain codon sets can be synthesized using commercial nucleic acid synthesizers (available from, for example, Applied Biosystems, Foster City, CA), or can be obtained commercially (for example, from Life Technologies, Rockville, MD). A set of oligonucleotides synthesized having a particular codon set will typically include a plurality of oligonucleotides with different sequences, the differences established by the codon set within the overall sequence. Oligonucleotides used according to the present invention have sequences that allow for hybridization to a VNAR nucleic acid template and also may where convenient include restriction enzyme sites. “Cell”, “cell line”, and “cell culture” are used interchangeably (unless the context indicates otherwise) and such designations include all progeny of a cell or cell line. Thus, for example, terms like “transformants” and “transformed cells” include the primary subject cell and cultures derived therefrom without regard for the number of transfers. It is also understood that all progeny may not be precisely identical in DNA content, due to deliberate or inadvertent mutations. Mutant progeny that have the same function or biological activity as screened for in the originally transformed cell are included. “Control sequences” when referring to expression means DNA sequences necessary for the expression of an operably linked coding sequence in a particular host organism. The control sequences that are suitable for prokaryotes, for example, include a promoter, optionally an operator sequence, a ribosome binding site, etc. Eukaryotic cells use control sequences such as promoters, polyadenylation signals, and enhancers. The term “coat protein” means a protein, at least a portion of which is present on the surface of the virus particle. From a functional perspective, a coat protein is any protein which associates with a virus particle during the viral assembly process in a host cell, and remains associated with the assembled virus until it infects another host cell. The “detection limit” for a chemical entity in a particular assay is the minimum concentration of that entity which can be detected above the background level for that assay. For example, in the phage ELISA, the “detection limit” for a particular phage displaying a particular antigen binding fragment is the phage concentration at which the particular phage produces an ELISA signal above that produced by a control phage not displaying the antigen binding fragment. A “fusion protein” and a “fusion polypeptide” refer to a polypeptide having two portions covalently linked together, where each of the portions is a polypeptide having a different property. The property may be a biological property, such as activity in vitro or in vivo. The property may also be a simple chemical or physical property, such as binding to a target antigen, catalysis of a reaction, etc. The two portions may be linked directly by a single peptide bond or through a peptide linker containing one or more amino acid residues. Generally, the two portions and the linker will be in reading frame with each other. Preferably, the two portions of the polypeptide are obtained from heterologous or different polypeptides. The term “fusion protein” in this text means, in general terms, one or more proteins joined together by chemical means, including hydrogen bonds or salt bridges, or by peptide bonds through protein synthesis or both. Typically fusion proteins will be prepared by DNA recombination techniques and may be referred to herein as recombinant fusion proteins. “Heterologous DNA” is any DNA that is introduced into a host cell. The DNA may be derived from a variety of sources including genomic DNA, cDNA, synthetic DNA and fusions or combinations of these. The DNA may include DNA from the same cell or cell type as the host or recipient cell or DNA from a different cell type, for example, from an allogenic or xenogenic source. The DNA may, optionally, include marker or selection genes, for example, antibiotic resistance genes, temperature resistance genes, etc. A “highly diverse position” refers to a position of an amino acid located in the variable regions of the light and heavy chains that have a number of different amino acid represented at the position when the amino acid sequences of known and/or naturally occurring antibodies or antigen binding fragments are compared. The highly diverse positions are typically in the CDR or HV regions. “Identity” describes the relationship between two or more polypeptide sequences or two or more polynucleotide sequences, as determined by comparing the sequences. Identity also means the degree of sequence relatedness (homology) between polypeptide or polynucleotide sequences, as the case may be, as determined by the match between strings of such sequences. While there exist a number of methods to measure identity between two polypeptide or two polynucleotide sequences, methods commonly employed to determine identity are codified in computer programs. Preferred computer programs to determine identity between two sequences include, but are not limited to, GCG program package (Devereux, et al., Nucleic acids Research, 12, 387 (1984), BLASTP, BLASTN, and FASTA (Atschul et al., J. Molec. Biol. (1990) 215, 403). Preferably, the amino acid sequence of the protein has at least 45% identity, using the default parameters of the BLAST computer program (Atschul et al., J. Mol. Biol. (1990) 215, 403-410) provided by HGMP (Human Genome Mapping Project), at the amino acid level, to the amino acid sequences disclosed herein. More preferably, the protein sequence may have at least 45%, 46%, 47%, 48%, 49%, 50%, 55%, 60%, 65%, 66%, 67%, 68%, 69%, 70%, 75%, 80%, 85%, 90% and still more preferably 95% (still more preferably at least 96%, 97%, 98% or 99%) identity, at the nucleic acid or amino acid level, to the amino acid sequences as shown herein. The protein may also comprise a sequence which has at least 45%, 46%, 47%, 48%, 49%, 50%, 50%, 55%, 60%, 65%, 66%, 67%, 68%, 69%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity with a sequence disclosed herein, using the default parameters of the BLAST computer program provided by HGMP, thereto A “library” refers to a plurality of VNARs or VNAR fragment sequences (for example, polypeptides of the invention), or the nucleic acids that encode these sequences, the sequences being different in the combination of variant amino acids that are introduced into these sequences according to the methods of the invention. “Ligation” is the process of forming phosphodiester bonds between two nucleic acid fragments. For ligation of the two fragments, the ends of the fragments must be compatible with each other. In some cases, the ends will be directly compatible after endonuclease digestion. However, it may be necessary first to convert the staggered ends commonly produced after endonuclease digestion to blunt ends to make them compatible for ligation. For blunting the ends, the DNA is treated in a suitable buffer for at least 15 minutes at 15°C with about 10 units of the Klenow fragment of DNA polymerase I or T4 DNA polymerase in the presence of the four deoxyribonucleotide triphosphates. The DNA is then purified by phenol- chloroform extraction and ethanol precipitation or by silica purification. The DNA fragments that are to be ligated together are put in solution in about equimolar amounts. The solution will also contain ATP, ligase buffer, and a ligase such as T4 DNA ligase at about 10 units per 0.5 µg of DNA. If the DNA is to be ligated into a vector, the vector is first linearized by digestion with the appropriate restriction endonuclease(s). The linearized fragment is then treated with bacterial alkaline phosphatase or calf intestinal phosphatase to prevent self-ligation during the ligation step. A “mutation” is a deletion, insertion, or substitution of a nucleotide(s) relative to a reference nucleotide sequence, such as a wild type sequence. “Natural” or “naturally occurring” VNARs, refers to VNARs identified from a non-synthetic source, for example, from a tissue source obtained ex vivo, or from the serum of an animal of the Elasmobranchii subclass. These VNARs can include VNARs generated in any type of immune response, either natural or otherwise induced. Natural VNARs include the amino acid sequences, and the nucleotide sequences that constitute or encode these antibodies. As used herein, natural VNARs are different than “synthetic VNARs”, synthetic VNARs referring to VNAR sequences that have been changed from a source or template sequence, for example, by the replacement, deletion, or addition, of an amino acid, or more than one amino acid, at a certain position with a different amino acid, the different amino acid providing an antibody sequence different from the source antibody sequence. The term “nucleic acid construct” generally refers to any length of nucleic acid which may be DNA, cDNA or RNA such as mRNA obtained by cloning or produced by chemical synthesis. The DNA may be single or double stranded. Single stranded DNA may be the coding sense strand, or it may be the non-coding or anti-sense strand. For therapeutic use, the nucleic acid construct is preferably in a form capable of being expressed in the subject to be treated. “Operably linked” when referring to nucleic acids means that the nucleic acids are placed in a functional relationship with another nucleic acid sequence. For example, DNA for a presequence or secretory leader is operably linked to DNA for a polypeptide if it is expressed as a preprotein that participates in the secretion of the polypeptide; a promotor or enhancer is operably linked to a coding sequence if it affects the transcription of the sequence; or a ribosome binding site is operably linked to a coding sequence if it is positioned so as to facilitate translation. Generally, “operably linked” means that the DNA sequences being linked are contiguous and, in the case of a secretory leader, contingent and in reading frame. However, enhancers do not have to be contiguous. Linking is accomplished by ligation at convenient restriction sites. If such sites do not exist, the synthetic oligonucleotide adapters or linkers are used in accord with conventional practice. The term “protein” means, in general terms, a plurality of amino acid residues joined together by peptide bonds. It is used interchangeably and means the same as peptide, oligopeptide, oligomer or polypeptide, and includes glycoproteins and derivatives thereof. The term “protein” is also intended to include fragments, analogues, variants and derivatives of a protein wherein the fragment, analogue, variant or derivative retains essentially the same biological activity or function as a reference protein. Examples of protein analogues and derivatives include peptide nucleic acids, and DARPins (Designed Ankyrin Repeat Proteins). A fragment, analogue, variant or derivative of the protein may be at least 25 preferably 30 or 40, or up to 50 or 100, or 60 to 120 amino acids long, depending on the length of the original protein sequence from which it is derived. A length of 90 to 120, 100 to 110 amino acids may be convenient in some instances. The fragment, derivative, variant or analogue of the protein may be (i) one in which one or more of the amino acid residues are substituted with a conserved or non-conserved amino acid residue (preferably, a conserved amino acid residue) and such substituted amino acid residue may or may not be one encoded by the genetic code, or (ii) one in which one or more of the amino acid residues includes a substituent group, or (iii) one in which the additional amino acids are fused to the mature polypeptide, such as a leader or auxiliary sequence which is employed for purification of the polypeptide. Such fragments, derivatives, variants and analogues are deemed to be within the scope of those skilled in the art from the teachings herein. “Oligonucleotides” are short-length, single- or double-stranded polydeoxynucleotides that are chemically synthesized by known methods (such as phosphotriester, phosphite, or phosphoramidite chemistry, using solid-phase techniques). Further methods include the polymerase chain reaction (PCR) used if the entire nucleic acid sequence of the gene is known, or the sequence of the nucleic acid complementary to the coding strand is available. Alternatively, if the target amino acid sequence is known, one may infer potential nucleic acid sequences using known and preferred coding residues for each amino acid residue. The oligonucleotides can be purified on polyacrylamide gels or molecular sizing columns or by precipitation. DNA is “purified” when the DNA is separated from non-nucleic acid impurities (which may be polar, non-polar, ionic, etc.). A “source” or “template” VNAR, as used herein, refers to a VNAR or VNAR antigen binding fragment whose antigen binding sequence serves as the template sequence upon which diversification according to the criteria described herein is performed. An antigen binding sequence generally includes within a VNAR preferably at least one CDR, preferably including framework regions. A “transcription regulatory element” will contain one or more of the following components: an enhancer element, a promoter, an operator sequence, a repressor gene, and a transcription termination sequence. “Transformation” means a process whereby a cell takes up DNA and becomes a “transformant”. The DNA uptake may be permanent or transient. A “transformant” is a cell which has taken up and maintained DNA as evidenced by the expression of a phenotype associated with the DNA (e.g., antibiotic resistance conferred by a protein encoded by the DNA). A “variant” or “mutant” of a starting or reference polypeptide (for example, a source VNAR or a CDR thereof), such as a fusion protein (polypeptide) or a heterologous polypeptide (heterologous to a phage), is a polypeptide that (1) has an amino acid sequence different from that of the starting or reference polypeptide and (2) was derived from the starting or reference polypeptide through either natural or artificial mutagenesis. Such variants include, for example, deletions from, and/or insertions into and/or substitutions of, residues within the amino acid sequence of the polypeptide of interest. For example, a fusion polypeptide of the invention generated using an oligonucleotide comprising a nonrandom codon set that encodes a sequence with a variant amino acid (with respect to the amino acid found at the corresponding position in a source VNAR or antigen binding fragment) would be a variant polypeptide with respect to a source VNAR or antigen binding fragment. Thus, a variant CDR refers to a CDR comprising a variant sequence with respect to a starting or reference polypeptide sequence (such as that of a source VNAR or antigen binding fragment). A variant amino acid, in this context, refers to an amino acid different from the amino acid at the corresponding position in a starting or reference polypeptide sequence (such as that of a source VNAR or antigen binding fragment). Any combination of deletion, insertion, and substitution may be made to arrive at the final variant or mutant construct, provided that the final construct possesses the desired functional characteristics. The amino acid changes also may alter post-translational processes of the polypeptide, such as changing the number or position of glycosylation sites. A “wild-type” or “reference” sequence or the sequence of a “wild-type” or “reference” protein/polypeptide, such as a coat protein, or a CDR of a source VNAR, may be the reference sequence from which variant polypeptides are derived through the introduction of mutations. In general, the “wild-type” sequence for a given protein is the sequence that is most common in nature. Similarly, a “wild-type” gene sequence is the sequence for that gene which is most commonly found in nature. Mutations may be introduced into a “wild-type” gene (and thus the protein it encodes) either through natural processes or through man induced means. The products of such processes are “variant” or “mutant” forms of the original “wild-type” protein or gene. A “humanised” antigen specific antigen binding molecule may be modified at one or more amino acid sequence position to reduce the potential for immunogenicity in vivo, while retaining functional binding activity for the specific epitopes on the specific antigen. Humanization of antibody variable domains is a technique well-known in the art to modify an antibody which has been raised, in a species other than humans, against a therapeutically useful target so that the humanized form may avoid unwanted immunological reaction when administered to a human subject. The methods involved in humanization are summarized in Almagro J.C and William Strohl W. Antibody Engineering: Humanization, Affinity Maturation, and Selection Techniques in Therapeutic Monoclonal Antibodies: From Bench to Clinic. Edited by An J.2009 John Wiley & Sons, Inc and in Strohl W.R. and Strohl L.M., Therapeutic Antibody Engineering, Woodhead Publishing 2012. Although IgNARs have distinct origins compared to immunoglobulins and have very little sequence homology compared to immunoglobulin variable domains there are some structural similarities between immunoglobulin and IgNAR variable domains, so that similar processes can be applied to the VNAR domain. For example, WO2013/167883, incorporated by reference, provides a description of the humanization of VNARs, see also Kovalenko O.V., et al. J Biol Chem.2013.288(24): p.17408-19. A humanised antigen specific binding molecule may differ from a wild-type antigen specific binding molecule by substituting one or more framework amino acid residues with a corresponding framework amino acid residue of DPK-9. DPK-9 is a human germline VL scaffold, a member of the variable kappa subgroup 1 (Vκ1). DPK-9 has a sequence according to: DIQMTQSPSSLSASVGDRVTITCRASQSISSYLNWYQQKPGKAPKLLIYAASSLQSGVPS RFSGSGSG TDFTLTISSLQPEDFATYYCQQSYSTPNTFGQGTKVEIK (SEQ ID NO:132) The term "chimeric antigen receptors (CARs)," as used herein, may refer to artificial T-cell receptors, chimeric T-cell receptors, or chimeric immunoreceptors, for example, and encompass engineered receptors that graft an artificial specificity onto a particular immune effector cell. CARs may be employed to impart the specificity of an antigen-specific binding protein, such as a monoclonal antibody or VNAR, onto a T cell, thereby allowing a large number of specific T cells to be generated, for example, for use in adoptive cell therapy. CARs may direct the specificity of the cell to a tumour associated antigen, for example. CARs may comprise an intracellular activation domain, a transmembrane domain, and an extracellular domain comprising a tumour associated antigen binding region. In particular aspects, CARs comprise fusions of single-chain variable fragments (scFv) derived from monoclonal antibodies fused to CD3-zeta transmembrane and endodomains. In other particular aspects, CARs comprise fusions of the VNAR domains described herein with CD3-zeta transmembrane and endodomains. The specificity of other CAR designs may be derived from ligands of receptors (e.g., peptides) or from pattern-recognition receptors, such as Dectins. In particular embodiments, one can target malignant B cells by redirecting the specificity of T cells by using a CAR specific for the B-lineage molecule, CD 19. In certain cases, the spacing of the antigen-recognition domain can be modified to reduce activation-induced cell death. In certain cases, CARs comprise domains for additional co-stimulatory signalling, such as CD3-zeta, FcR, CD27, CD28, CD 137, DAP 10, and/or OX40. In some cases, molecules can be co- expressed with the CAR, including co-stimulatory molecules, reporter genes for imaging (e.g., for positron emission tomography), gene products that conditionally ablate the T cells upon addition of a pro-drug, homing receptors, chemokines, chemokine receptors, cytokines, and cytokine receptors. The term “conjugation” as used herein may refer to any method of chemically linking two or more chemical moieties. Typically, conjugation will be via covalent bond. In the context of the present invention, at least one of the chemical moieties will be a polypeptide and in some cases the conjugation will involve two or more polypeptides, one or more of which may be generated by recombinant DNA technology. A number of systems for conjugating polypeptides are known in the art. For example, conjugation can be achieved through a lysine residue present in the polypeptide molecule using N- hydroxy-succinimide or through a cysteine residue present in the polypeptide molecule using maleimidobenzoyl sulfosuccinimide ester. In some embodiments, conjugation occurs through a short- acting, degradable linkage including, but not limited to, physiologically cleavable linkages including ester, carbonate ester, carbamate, sulfate, phosphate, acyloxyalkyl ether, acetal, and ketal, hydrazone, oxime and disulphide linkages. In some embodiments linkers that are cleavable by intracellular or extracellular enzymes, such as cathepsin family members, cleavable under reducing conditions or acidic pH are incorporated to enable releases of conjugated moieties from the polypeptide or protein to which it is conjugated. A particularly preferred method of conjugation is the use of intein-based technology (US2006247417) Briefly, the protein of interest is expressed as an N terminal fusion of an engineered intein domain (Muir 2006 Nature 442, 517–518). Subsequent N to S acyl shift at the protein-intein union results in a thioester linked intermediate that can be chemically cleaved with bis-aminoxy agents or amino-thiols to give the desired protein C-terminal aminoxy or thiol derivative, respectively. These C-terminal aminoxy and thiol derivatives can be reacted with aldehyde / ketone and maleimide functionalised moieties, respectively, in a chemoselective fashion to give the site-specific C-terminally modified protein. In another preferred method of conjugation the VNARs are directly expressed with an additional cysteine at or near the C-terminal region of the VNAR or incorporated within a short C-terminal tag sequence enabling conjugation with thiol reactive payloads such as maleimide functionalised moieties. Conjugation as referred to herein is also intended to encompass the use of a linker moiety, which may impart a number of useful properties. Linker moieties include, but are not limited to, peptide sequences such as poly-glycine, gly-ser, val-cit or val-ala. In certain cases, the linker moiety may be selected such that it is cleavable under certain conditions, for example via the use of enzymes, nucleophilic/basic reagents, reducing agents, photo-irradiation, electrophilic/acidic reagents, organometallic and metal reagents, or oxidizing reagents, or the linker may be specifically selected to resist cleavage under such conditions. Polypeptides may be conjugated to a variety of functional moieties in order to achieve a number of goals. Examples of functional moieties include, but are not limited to, polymers such as polyethylene glycol in order to reduce immunogenicity and antigenicity or to improve solubility. Further non-limiting examples include the conjugation of a polypeptide to a therapeutic agent or a cytotoxic agent. The term “detectable label” is used herein to specify that an entity can be visualized or otherwise detected by spectroscopic, photochemical, biochemical, immunochemical, electrical, optical, chemical or other means. The detectable label may be selected such that it generates a signal which can be measured and whose intensity is proportional to the amount of bound entity. A wide variety of systems for labelling and/or detecting proteins and peptides are known in the art. A label may be directly detectable (i.e., it does not require any further reaction or manipulation to be detectable, e.g., a fluorophore is directly detectable) or it may be indirectly detectable (i.e., it is made detectable through reaction or binding with another entity that is detectable, e.g., a hapten is detectable by immunostaining after reaction with an appropriate antibody comprising a reporter such as a fluorophore). Suitable detectable agents include, but are not limited to, radionuclides, fluorophores, chemiluminescent agents, microparticles, enzymes, colorimetric labels, magnetic labels, haptens, molecular beacons, and aptamer beacons. Methods of killing or inhibiting the growth of a cells expressing ROR1 in vitro or in a patient are contemplated herein, in general, the term “killing” as used herein in the context of cells means causing a cell death. This may be achieved by a number of mechanisms, such as necrosis or other cells injury, or the induction of apoptosis. The phrases “inhibiting the growth” or “inhibiting proliferation” when used herein are intended to encompass the prevention of cell development, more specifically the prevention of cell division. As used herein, an alkyl group is a straight chain or branched, substituted or unsubstituted group (preferably unsubstituted) containing from 1 to 40 carbon atoms. An alkyl group may optionally be substituted at any position. The term "alkenyl," as used herein, denotes a group derived from the removal of a single hydrogen atom from a straight- or branched-chain aliphatic moiety having at least one carbon- carbon double bond. The term "alkynyl," as used herein, refers to a group derived from the removal of a single hydrogen atom from a straight- or branched-chain aliphatic moiety having at least one carbon- carbon triple bond. The term ‘alkyl’, ‘aryl’, ‘heteroaryl’ etc also include multivalent species, for example alkylene, arylene, ‘heteroarylene’ etc. Examples of alkylene groups include ethylene (-CH ₂ -CH ₂ -), and propylene (-CH ₂ - CH2-CH2-). An exemplary arylene group is phenylene (-C6H4-), and an exemplary heteroarylene group is pyridinylene (-C5H3N-). Aromatic rings are cyclic aromatic groups that may have 0, 1, 2 or more, preferably 0, 1 or 2 ring heteroatoms. Aromatic rings may be optionally substituted and/or may be fused to one or more aromatic or non-aromatic rings (preferably aromatic), which may contain 0, 1, 2, or more ring heteroatoms, to form a polycyclic ring system. Aromatic rings include both aryl and heteroaryl groups. Aryl and heteroaryl groups may be mononuclear, i.e. having only one aromatic ring (like for example phenyl or phenylene), or polynuclear, i.e. having two or more aromatic rings which may be fused (like for example napthyl or naphthylene), individually covalently linked (like for example biphenyl), and/or a combination of both fused and individually linked aromatic rings. Preferably the aryl or heteroaryl group is an aromatic group which is substantially conjugated over substantially the whole group. Aryl groups may contain from 5 to 40 ring carbon atoms, from 5 to 25 carbon atoms, from 5 to 20 carbon atoms, or from 5 to 12 carbon atoms. Heteroaryl groups may be from 5 to 40 membered, from 5 to 25 membered, from 5 to 20 membered or from 5 to 12 membered rings, containing 1 or more ring heteroatoms selected from N, O, S and P. An aryl or heteroaryl may be fused to one or more aromatic or non-aromatic rings (preferably an aromatic ring) to form a polycyclic ring system. Aryl and heteroaryl preferably denote a mono-, bi- or tricyclic aromatic or heteroaromatic group with up to 25 ring atoms that may also comprise condensed rings and is optionally substituted. Preferred aryl groups include, without limitation, benzene, biphenylene, triphenylene, [1,1':3',1'']terphenyl-2'-ylene, naphthalene, anthracene, binaphthylene, phenanthrene, pyrene, dihydropyrene, chrysene, perylene, tetracene, pentacene, benzopyrene, fluorene, indene, indenofluorene, spirobifluorene, etc. Preferred heteroaryl groups include, without limitation, 5-membered rings like pyrrole, pyrazole, silole, imidazole, 1,2,3-triazole, 1,2,4-triazole, tetrazole, furan, thiophene, selenophene, oxazole, isoxazole, 1,2-thiazole, 1,3-thiazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3- thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole, 6-membered rings like pyridine, pyridazine, pyrimidine, pyrazine, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine, 1,2,4,5-tetrazine, 1,2,3,4- tetrazine, 1,2,3,5-tetrazine, and fused systems like carbazole, indole, isoindole, indolizine, indazole, benzimidazole, benzotriazole, purine, naphthimidazole, phenanthrimidazole, pyridimidazole, pyrazin- imidazole, quinoxalinimidazole, benzoxazole, naphthoxazole, anthroxazole, phenanthroxazole, isoxazole, benzothiazole, benzofuran, isobenzofuran, dibenzofuran, quinoline, isoquinoline, pteridine, benzo-5,6-quinoline, benzo-6,7-quinoline, benzo-7,8-quinoline, benzoisoquinoline, acridine, phenothiazine, phenoxazine, benzopyridazine, benzopyrimidine, quinoxaline, phenazine, naphthyridine, azacarbazole, benzocarboline, phenanthridine, phenanthroline, thieno[2,3b]thiophene, thieno[3,2b]thiophene, dithienothiophene, dithienopyridine, isobenzothiophene, dibenzothiophene, benzothiadiazothiophene, 2,5-dihydropyrrolo[3,4-c]pyrrol-1,4-dione (diketopyrrolopyrrole, DPP), 2-oxo- 1H-indol-3-ylidene, [3,3'-bipyrrolo[2,3-b]pyridinylidene]-2,2'(1H,1'H)-dione (pyridine isoindigo) and (3E)- 3-(2-oxo-1H-indol-3-ylidene)-1H-indol-2-one (isoindigo), or combinations thereof. The heteroaryl groups may be substituted with alkyl, alkoxy, thioalkyl, fluoro, fluoroalkyl or further aryl or heteroaryl substituents. Preferably a heteroaryl group is thiophene. Particularly preferred heteroatoms are selected from O, S, N, P and Si. Typically, hydrogen will complete the valency of a heteroatom included in the molecules of the invention, e.g. for N there may be -NH- or -NH2 where one or two other groups are involved. As used herein, the term “optionally substituted” means that one or more of the hydrogen atoms in the optionally substituted moiety is replaced by a suitable substituent. Unless otherwise indicated, an "optionally substituted” group may have a suitable substituent at each substitutable position of the group, and when more than one position in any given structure may be substituted with more than one substituent selected from a specified group, the substituent may be either the same or different at every position. Combinations of substituents envisioned by this invention are preferably those that result in the formation of stable compounds. The term "stable", as used herein, refers to compounds that are chemically feasible and can exist for long enough at room temperature (i.e.16-25°C) to allow for their detection, isolation and/or use in chemical synthesis. Any of the above groups (for example, those referred to herein as “optionally substituted”, including alkyl, aryl and heteroaryl groups) may optionally comprise one or more substituents, preferably selected from silyl, sulfo, sulfonyl, formyl, amino, imino, nitrilo, mercapto, cyano, nitro, halogen, -NCO, -NCS, - OCN, -SCN, -C(=O)NR ⁰ R ⁰⁰ , -C(=O)X ⁰ , -C(=O)R ⁰ , -NR ⁰ R ⁰⁰ , C _1-12 alkyl, C _1-12 alkenyl, C _1-12 alkynyl, C _6- 12aryl, C3-12cycloalkyl, heterocycloalkyl having 4 to 12 ring atoms, heteroaryl having 5 to 12 ring atoms, C1-12 alkoxy, hydroxy, C1-12 alkylcarbonyl, C1-12 alkoxy-carbonyl, C1-12 alkylcarbonyloxy or C1-12 alkoxycarbonyloxy wherein one or more H atoms are optionally replaced by F or Cl and/or combinations thereof; wherein X ⁰ is halogen and R ⁰ and R ⁰⁰ are, independently, H or optionally substituted C _1-12 alkyl. The optional substituents may comprise all chemically possible combinations in the same group and/or a plurality of the aforementioned groups (for example amino and sulfonyl if directly attached to each other represent a sulfamoyl radical). In one embodiment, the substituent is not acyl. As used herein acyl refers to an acyl group which is a moiety derived by the removal of one or more hydroxyl groups from an oxoacid, such as a carboxylic acid. It contains a double-bonded oxygen atom and an alkyl group. In some embodiments the groups may be unsubstituted. For example, the anthracycline (PNU) derivative may be of formula (V): wherein [X] is an optional spacer selected from the group comprising unsubstituted alkyl groups, unsubstituted heteroalkyl groups, unsubstituted aryl groups, unsubstituted heteroaryl groups, one or more heteroatoms, polyethylene glycol, or a combination thereof; [L1] and [L2] are optional linkers selected from the group consisting of valine (Val), citrulline (Cit), alanine (Ala), asparagine (Asn), a peptide, -(CH2)n-, -(CH2CH2O)n-, p-aminobenzyloxycarbonyl (PAB), Val-Cit- PAB, Val-Ala-PAB, Ala-Ala-Asn-PAB, Val-Ala, Asn-Ala, any amino acid except glycine, and combinations thereof. In embodiments wherein the groups are unsubstituted, [X] is preferably selected from the group comprising polyethylene glycol and , wherein represents the point of attachment to the rest of the molecule and wherein [R] is an optional spacer selected from the group comprising unsubstituted alkyl groups, unsubstituted heteroalkyl groups, unsubstituted aryl groups, unsubstituted heteroaryl groups, one or more heteroatoms, polyethylene glycol, or a combination thereof. In general, the term PAB is intended to mean p-aminobenzyloxycarbonyl. Occasionally in the literature, the term PAB may be used to indicated p-aminobenzyl. In the present specification, PAB is intended to indicate p-aminobenzyloxycarbonyl. The term “target-binding molecule” refers to any molecule that binds to a given target. In this context, “target” and “antigen” may be used interchangeably. Examples of target-binding molecules include natural or recombinant proteins including immunoglobulins or antibodies, immunoglobulin Fc regions, immunoglobulin Fab regions, Fab, Fab’, Fv, Fv-Fc, single chain Fv (scFv), scFv-Fc, (scFv)2, diabodies, triabodies, tetrabodies, bispecific t-cell engagers , inteins, intein fusions, VNAR domains, single domain antibodies (sdAb), VH domains, scaffold proteins (affibodies, centyrins, darpins etc.) and nucleic acids including aptamers or small molecules or natural products that have been developed to bind to the target or naturally bind to the target. Chemical modification of proteins and biomolecules to introduce thiols is well established. Methods include reaction of amine groups with 2-iminothiolane (Traut’s reagent), modification of amine groups with NHS-ester containing heterobifunctional agents such as N-succinimidyl S-acetylthiolate (SATA) or N-succinimidyl-4-(2-pyridyldithio)butanoate (SPDB), followed by treatment with hydroxylamine and reducing agents respectively and cleavage of engineered intein-fusion proteins with cysteamine to generate C-terminal thiol proteins and peptides. The phrase “selected from the group comprising” may be substituted with the phrase “selected from the group consisting of” and vice versa, wherever they occur herein. The PNU derivatives described herein may be prepared accordingly to standard synthesis methods. Mass spectrometry may be used to verify that the correct molecules have been produced (Table 4). Table 4: Characterisation of PNU derivatives by mass spectrometry Preferred embodiments include target-binding molecule-drug conjugate selected from the group consisting of: ^ G3CP / P2A7 each fused to hFc (S239C+S442C) comprising a [G4S]3 linker and KIH technology, conjugated to vcMMAE via each S239C and each S442C ^ G3CP / 4D2 each fused to hFc (S239C+S442C) comprising a [G4S]3 linker and KIH technology, conjugated to vcMMAE via each S239C and each S442C ^ G3CP / E02 each fused to hFc (S239C+S442C) comprising a [G4S]3 linker and KIH technology, conjugated to vcMMAE via each S239C and each S442C ^ 1H8 / P2A7 each fused to hFc (S239C+S442C) comprising a [G4S]3 linker and KIH technology, conjugated to vcMMAE via each S239C and each S442C ^ 1H8 / 4D2 each fused to hFc (S239C+S442C) comprising a [G4S]3 linker and KIH technology, conjugated to vcMMAE via each S239C and each S442C ^ 1H8 / E02 each fused to hFc (S239C+S442C) comprising a [G4S]3 linker and KIH technology, conjugated to vcMMAE via each S239C and each S442C ^ G3CPG4 / P2A7 each fused to hFc (S239C+S442C) comprising a [G4S]3 linker and KIH technology, conjugated to vcMMAE via each S239C and each S442C ^ G3CPG4 / 4D2 each fused to hFc (S239C+S442C) comprising a [G4S]3 linker and KIH technology, conjugated to vcMMAE via each S239C and each S442C ^ G3CPG4 / E02 each fused to hFc (S239C+S442C) comprising a [G4S]3 linker and KIH technology, conjugated to vcMMAE via each S239C and each S442C ^ P3A1 / P2A7 each fused to hFc (S239C+S442C) comprising a [G4S]3 linker and KIH technology, conjugated to vcMMAE via each S239C and each S442C ^ P3A1 / 4D2 each fused to hFc (S239C+S442C) comprising a [G4S]3 linker and KIH technology, conjugated to vcMMAE via each S239C and each S442C ^ P3A1 / E02 each fused to hFc (S239C+S442C) comprising a [G4S]3 linker and KIH technology, conjugated to vcMMAE via each S239C and each S442C ^ G3CP / P2A7 each fused to hFc (S239C+S442C) comprising a G4S linker and KIH technology, conjugated to vcMMAE via each S239C and each S442C ^ G3CP / 4D2 each fused to hFc (S239C+S442C) comprising a G4S linker and KIH technology, conjugated to vcMMAE via each S239C and each S442C ^ G3CP / E02 each fused to hFc (S239C+S442C) comprising a G4S linker and KIH technology, conjugated to vcMMAE via each S239C and each S442C ^ P3A1 / P2A7 each fused to hFc (S239C+S442C) comprising a G4S linker and KIH technology, conjugated to vcMMAE via each S239C and each S442C ^ P3A1 / 4D2 each fused to hFc (S239C+S442C) comprising a G4S linker and KIH technology, conjugated to vcMMAE via each S239C and each S442C ^ P3A1 / E02 each fused to hFc (S239C+S442C) comprising a G4S linker and KIH technology, conjugated to vcMMAE via each S239C and each S442C ^ 1H8 / P2A7 each fused to hFc (S239C+S442C) comprising a G4S linker and KIH technology, conjugated to vcMMAE via each S239C and each S442C ^ 1H8 / 4D2 each fused to hFc (S239C+S442C) comprising a G4S linker and KIH technology, conjugated to vcMMAE via each S239C and each S442C ^ 1H8 / E02 each fused to hFc (S239C+S442C) comprising a G4S linker and KIH technology, conjugated to vcMMAE via each S239C and each S442C ^ G3CPG4 / P2A7 each fused to hFc (S239C+S442C) comprising a G4S linker and KIH technology, conjugated to vcMMAE via each S239C and each S442C ^ G3CPG4 / 4D2 each fused to hFc (S239C+S442C) comprising a G4S linker and KIH technology, conjugated to vcMMAE via each S239C and each S442C ^ G3CPG4 / E02 each fused to hFc (S239C+S442C) comprising a G4S linker and KIH technology, conjugated to vcMMAE via each S239C and each S442C ^ Further preferred embodiments include target-binding molecule-drug conjugate selected from the group consisting of: ^ G3CP / P2A7 each fused to hFc (S239C) comprising a [G4S]3 linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S239C ^ G3CP / 4D2 each fused to hFc (S239C) comprising a [G4S]3 linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S239C ^ G3CP / E02 each fused to hFc (S239C) comprising a [G4S]3 linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S239C ^ 1H8 / P2A7 each fused to hFc (S239C) comprising a [G4S]3 linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S239C ^ 1H8 / 4D2 each fused to hFc (S239C) comprising a [G4S]3 linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S239C ^ 1H8 / E02 each fused to hFc (S239C) comprising a [G4S]3 linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S239C ^ G3CPG4 / P2A7 each fused to hFc (S239C) comprising a [G4S]3 linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S239C ^ G3CPG4 / 4D2 each fused to hFc (S239C) comprising a [G4S]3 linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S239C ^ G3CPG4 / E02 each fused to hFc (S239C) comprising a [G4S]3 linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S239C ^ P3A1 / P2A7 each fused to hFc (S239C) comprising a [G4S]3 linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S239C ^ P3A1 / 4D2 each fused to hFc (S239C) comprising a [G4S]3 linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S239C ^ P3A1 / E02 each fused to hFc (S239C) comprising a [G4S]3 linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S239C ^ G3CP / P2A7 each fused to hFc (S239C) comprising a G4S linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S239C ^ G3CP / 4D2 each fused to hFc (S239C) comprising a G4S linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S239C ^ G3CP / E02 each fused to hFc (S239C) comprising a G4S linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S239C ^ P3A1 / P2A7 each fused to hFc (S239C) comprising a G4S linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S239C ^ P3A1 / 4D2 each fused to hFc (S239C) comprising a G4S linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S239C ^ P3A1 / E02 each fused to hFc (S239C) comprising a G4S linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S239C ^ 1H8 / P2A7 each fused to hFc (S239C) comprising a G4S linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S239C ^ 1H8 / 4D2 each fused to hFc (S239C) comprising a G4S linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S239C ^ 1H8 / E02 each fused to hFc (S239C) comprising a G4S linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S239C ^ G3CPG4 / P2A7 each fused to hFc (S239C) comprising a G4S linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S239C ^ G3CPG4 / 4D2 each fused to hFc (S239C) comprising a G4S linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S239C ^ G3CPG4 / E02 each fused to hFc (S239C) comprising a G4S linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S239C Further preferred embodiments include target-binding molecule-drug conjugate selected from the group consisting of: ^ G3CP / P2A7 each fused to hFc (S239C) comprising a [G4S]3 linker and KIH technology, conjugated to va-EDA-PNU via each S239C ^ G3CP / 4D2 each fused to hFc (S239C) comprising a [G4S]3 linker and KIH technology, conjugated to va-EDA-PNU via each S239C ^ G3CP / E02 each fused to hFc (S239C) comprising a [G4S]3 linker and KIH technology, conjugated to va-EDA-PNU via each S239C ^ 1H8 / P2A7 each fused to hFc (S239C) comprising a [G4S]3 linker and KIH technology, conjugated to va-EDA-PNU via each S239C ^ 1H8 / 4D2 each fused to hFc (S239C) comprising a [G4S]3 linker and KIH technology, conjugated to va-EDA-PNU via each S239C ^ 1H8 / E02 each fused to hFc (S239C) comprising a [G4S]3 linker and KIH technology, conjugated to va-EDA-PNU via each S239C ^ G3CPG4 / P2A7 each fused to hFc (S239C) comprising a [G4S]3 linker and KIH technology, conjugated to va-EDA-PNU via each S239C ^ G3CPG4 / 4D2 each fused to hFc (S239C) comprising a [G4S]3 linker and KIH technology, conjugated to va-EDA-PNU via each S239C ^ G3CPG4 / E02 each fused to hFc (S239C) comprising a [G4S]3 linker and KIH technology, conjugated to va-EDA-PNU via each S239C ^ P3A1 / P2A7 each fused to hFc (S239C) comprising a [G4S]3 linker and KIH technology, conjugated to va-EDA-PNU via each S239C ^ P3A1 / 4D2 each fused to hFc (S239C) comprising a [G4S]3 linker and KIH technology, conjugated to va-EDA-PNU via each S239C ^ P3A1 / E02 each fused to hFc (S239C) comprising a [G4S]3 linker and KIH technology, conjugated to va-EDA-PNU via each S239C ^ G3CP / P2A7 each fused to hFc (S239C) comprising a G4S linker and KIH technology, conjugated to va-EDA-PNU via each S239C ^ G3CP / 4D2 each fused to hFc (S239C) comprising a G4S linker and KIH technology, conjugated to va-EDA-PNU via each S239C ^ G3CP / E02 each fused to hFc (S239C) comprising a G4S linker and KIH technology, conjugated to va-EDA-PNU via each S239C ^ P3A1 / P2A7 each fused to hFc (S239C) comprising a G4S linker and KIH technology, conjugated to va-EDA-PNU via each S239C ^ P3A1 / 4D2 each fused to hFc (S239C) comprising a G4S linker and KIH technology, conjugated to va-EDA-PNU via each S239C ^ P3A1 / E02 each fused to hFc (S239C) comprising a G4S linker and KIH technology, conjugated to va-EDA-PNU via each S239C ^ 1H8 / P2A7 each fused to hFc (S239C) comprising a G4S linker and KIH technology, conjugated to va-EDA-PNU via each S239C ^ 1H8 / 4D2 each fused to hFc (S239C) comprising a G4S linker and KIH technology, conjugated to va-EDA-PNU via each S239C ^ 1H8 / E02 each fused to hFc (S239C) comprising a G4S linker and KIH technology, conjugated to va-EDA-PNU via each S239C ^ G3CPG4 / P2A7 each fused to hFc (S239C) comprising a G4S linker and KIH technology, conjugated to va-EDA-PNU via each S239C ^ G3CPG4 / 4D2 each fused to hFc (S239C) comprising a G4S linker and KIH technology, conjugated to va-EDA-PNU via each S239C ^ G3CPG4 / E02 each fused to hFc (S239C) comprising a G4S linker and KIH technology, conjugated to va-EDA-PNU via each S239C Further preferred embodiments include target-binding molecule-drug conjugate selected from the group consisting of: ^ G3CP / P2A7 each fused to hFc (S442C) comprising a [G4S]3 linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S442C ^ G3CP / 4D2 each fused to hFc (S442C) comprising a [G4S]3 linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S442C ^ G3CP / E02 each fused to hFc (S442C) comprising a [G4S]3 linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S442C ^ 1H8 / P2A7 each fused to hFc (S442C) comprising a [G4S]3 linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S442C ^ 1H8 / 4D2 each fused to hFc (S442C) comprising a [G4S]3 linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S442C ^ 1H8 / E02 each fused to hFc (S442C) comprising a [G4S]3 linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S442C ^ G3CPG4 / P2A7 each fused to hFc (S442C) comprising a [G4S]3 linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S442C ^ G3CPG4 / 4D2 each fused to hFc (S442C) comprising a [G4S]3 linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S442C ^ G3CPG4 / E02 each fused to hFc (S442C) comprising a [G4S]3 linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S442C ^ P3A1 / P2A7 each fused to hFc (S442C) comprising a [G4S]3 linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S442C ^ P3A1 / 4D2 each fused to hFc (S442C) comprising a [G4S]3 linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S442C ^ P3A1 / E02 each fused to hFc (S442C) comprising a [G4S]3 linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S442C ^ G3CP / P2A7 each fused to hFc (S442C) comprising a G4S linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S442C ^ G3CP / 4D2 each fused to hFc (S442C) comprising a G4S linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S442C ^ G3CP / E02 each fused to hFc (S442C) comprising a G4S linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S442C ^ 1H8 / P2A7 each fused to hFc (S442C) comprising a G4S linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S442C ^ 1H8 / 4D2 each fused to hFc (S442C) comprising a G4S linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S442C ^ 1H8 / E02 each fused to hFc (S442C) comprising a G4S linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S442C ^ G3CPG4 / P2A7 each fused to hFc (S442C) comprising a G4S linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S442C ^ G3CPG4 / 4D2 each fused to hFc (S442C) comprising a G4S linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S442C ^ G3CPG4 / E02 each fused to hFc (S442C) comprising a G4S linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S442C ^ P3A1 / P2A7 each fused to hFc (S442C) comprising a G4S linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S442C ^ P3A1 / 4D2 each fused to hFc (S442C) comprising a G4S linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S442C ^ P3A1 / E02 each fused to hFc (S442C) comprising a G4S linker and KIH technology, conjugated to vc-PAB-EDA-PNU via each S442C Further preferred embodiments include target-binding molecule-drug conjugate selected from the group consisting of: ^ G3CP / P2A7 each fused to hFc (S442C) comprising a [G4S]3 linker and KIH technology, conjugated to va-EDA-PNU via each S442C ^ G3CP / 4D2 each fused to hFc (S442C) comprising a [G4S]3 linker and KIH technology, conjugated to va-EDA-PNU via each S442C ^ G3CP / E02 each fused to hFc (S442C) comprising a [G4S]3 linker and KIH technology, conjugated to va-EDA-PNU via each S442C ^ 1H8 / P2A7 each fused to hFc (S442C) comprising a [G4S]3 linker and KIH technology, conjugated to va-EDA-PNU via each S442C ^ 1H8 / 4D2 each fused to hFc (S442C) comprising a [G4S]3 linker and KIH technology, conjugated to va-EDA-PNU via each S442C ^ 1H8 / E02 each fused to hFc (S442C) comprising a [G4S]3 linker and KIH technology, conjugated to va-EDA-PNU via each S442C ^ G3CPG4 / P2A7 each fused to hFc (S442C) comprising a [G4S]3 linker and KIH technology, conjugated to va-EDA-PNU via each S442C ^ G3CPG4 / 4D2 each fused to hFc (S442C) comprising a [G4S]3 linker and KIH technology, conjugated to va-EDA-PNU via each S442C ^ G3CPG4 / E02 each fused to hFc (S442C) comprising a [G4S]3 linker and KIH technology, conjugated to va-EDA-PNU via each S442C ^ P3A1 / P2A7 each fused to hFc (S442C) comprising a [G4S]3 linker and KIH technology, conjugated to va-EDA-PNU via each S442C ^ P3A1 / 4D2 each fused to hFc (S442C) comprising a [G4S]3 linker and KIH technology, conjugated to va-EDA-PNU via each S442C ^ P3A1 / E02 each fused to hFc (S442C) comprising a [G4S]3 linker and KIH technology, conjugated to va-EDA-PNU via each S442C ^ G3CP / P2A7 each fused to hFc (S442C) comprising a G4S linker and KIH technology, conjugated to va-EDA-PNU via each S442C ^ G3CP / 4D2 each fused to hFc (S442C) comprising a G4S linker and KIH technology, conjugated to va-EDA-PNU via each S442C ^ G3CP / E02 each fused to hFc (S442C) comprising a G4S linker and KIH technology, conjugated to va-EDA-PNU via each S442C ^ P3A1 / P2A7 each fused to hFc (S442C) comprising a G4S linker and KIH technology, conjugated to va-EDA-PNU via each S442C ^ P3A1 / 4D2 each fused to hFc (S442C) comprising a G4S linker and KIH technology, conjugated to va-EDA-PNU via each S442C ^ P3A1 / E02 each fused to hFc (S442C) comprising a G4S linker and KIH technology, conjugated to va-EDA-PNU via each S442C ^ 1H8 / P2A7 each fused to hFc (S442C) comprising a G4S linker and KIH technology, conjugated to va-EDA-PNU via each S442C ^ 1H8 / 4D2 each fused to hFc (S442C) comprising a G4S linker and KIH technology, conjugated to va-EDA-PNU via each S442C ^ 1H8 / E02 each fused to hFc (S442C) comprising a G4S linker and KIH technology, conjugated to va-EDA-PNU via each S442C ^ G3CPG4 / P2A7 each fused to hFc (S442C) comprising a G4S linker and KIH technology, conjugated to va-EDA-PNU via each S442C ^ G3CPG4 / 4D2 each fused to hFc (S442C) comprising a G4S linker and KIH technology, conjugated to va-EDA-PNU via each S442C ^ G3CPG4 / E02 each fused to hFc (S442C) comprising a G4S linker and KIH technology, conjugated to va-EDA-PNU via each S442C Fc Silencing In one embodiment, an antibody of the invention comprises a “silenced” Fc region. Fc binding to FcγRs has the potential to impact efficacy and/or toxicity of antibodies and other Fc containing protein therapeutics through 3 different mechanisms: antibody-dependent cellular toxicity (ADCC), antibody- dependent cellular phagocytosis (ADCP) and complement dependent cytotoxicity (CDC) (reviewed in Liu 2020 Antibodies 9; 64). These are summarised below, where, for simplicity the term “antibody” is used to encompass all Fc containing proteins including VNAR Fc fusion proteins as disclosed herein. ADCC is mediated by Natural killer (NK) cells binding the Fc region of the antibody on antibody- labelled cells, predominantly through FcγRIIIa. This causes the release of NK lytic granules containing, for example, perforin & granzyme and leading to cell lysis. ADCP is mediated by phagocytotic cells, for example macrophages, monocytes and neutrophils, when the Fc region of the antibody on antibody-labelled cells interacts with corresponding activatory FcγRs on the surface of these phagocytic cells. This causes activation of the phagocytic cell, promoting clearance of the Fc-labelled cells from the body by phagocytosis. CDC occurs when sufficient Fc molecules engage the 6 globular heads of the C1q protein, initiating the proteolytic cascade of complement proteins and ultimately resulting in release of anaphylatoxins C3a and C5a, and formation of membrane attack complex (MAC). The MAC forms pores in the plasma membrane of target cells, leading to osmolysis. In some therapeutic contexts such Fc mediated effector function(s) may be undesirable. For example, where there is normal tissue expression of the antibody target which can lead to undesired on-target off-tumour immune activation and thereby potential toxicity issues. A number of strategies can be used to reduce or silence Fc effector activity. IgG isotypes have different affinities for the FcγRs (IgG1 > IgG3 > IgG2 > IgG4) and IgG2 and IgG4 backbones have been used to reduce Fc effector functions in therapeutics (Yu 2020 J Hematol & Oncol 13:45). In addition, Ser is naturally found at positions 330 and 331 in IgG4, and results in reduced FcγR binding when incorporated into IgG2 (Lund 1991 J Immunol 147:2657). Methods for reducing Fc effector function in the IgG1 isotype include a glycosylation through amino acid substitution at N297 position (N297Q/A/G) (Jacobsen 2017 JBC 292(5) 1865), because glycans attached at this position of the Fc are critical for efficient binding to FcγRs and C1q. Similarly, cell free protein expression (e.g. Sutro XpressCF ^TM ) or sugar remodelling / conjugation platforms (e.g. Synaffix GlycoConnect ^TM ) have the potential to reduce Fc effector function. Alternatively amino acid substitutions or modifications within the Fc:FcγR/C1q binding interface can be used to reduce IgG1 Fc effector activity (Sonderman 2020 Nature 406(6793):267). At least 39 human IgG1 residues are relevant to binding FcγRs, with substitutions between positions 232-239 of particular interest and many antibody variants in the clinic have substitutions in this area. For example, L234A/L235A (LALA) (Strohl 2009 Curr Opin Biotechnol 20,685), L234F/L235E/P331S (FES) (Oganesyan 2008 Biological Crystallography D64, 700–704), L234A/L235A/P329G (LALAPG) (Schlothauer 2016 PEDS 29:457-466), L234S/L235T/G236R (STR) (Wilkinson 2021 PLOS ONE). Asymmetric Fc mutations for reduced or silenced effector function have also been employed, for example HC-A L234D/L235E plus HC-B E233K/L234R/L235R (Escobar-Cabrera 2017 Antibodies 6, 7). Accordingly, in some embodiments, an antibody of the invention does not display the effector function or functions associated with a normal Fc region. In some embodiments, the Fc region of an antibody of the invention does not bind to or has reduced binding to one or more Fc receptors. In one embodiment, an antibody of the invention may show reduced binding to all Fc receptors. In one embodiment, an antibody of the invention does not bind to any Fc receptors. In another embodiment, the antibody does bind to one or more types of Fc receptor. In one embodiment, an antibody of the invention does not bind or has reduced binding to one or more FcγRs. For example, an antibody of the invention may not bind or may have reduced binding to FcγRIIIa. In one embodiment, an antibody of the invention does not bind or has reduced binding to C1q. In one embodiment, an antibody of the invention does not bind or has reduced binding to one or more FcγRs or C1q. In an alternative embodiment, an antibody of the invention does not bind or has reduced binding to one or more FcγRs, but does bind C1q. In one embodiment, an antibody of the invention in general may comprise an Fc region modification(s) that alter the half-life of the antibody. By “reduced binding”, it is meant that binding of the modified Fc region is reduced relative to the binding of a corresponding Fc region which has not been modified. In one embodiment, an antibody of the invention comprises a mutated Fc region, in particular, an Fc region comprising a mutation described herein. In one embodiment the Fc mutation is selected from the group comprising a mutation to remove, reduce or enhance binding of the Fc region to an Fc receptor, a mutation to increase, reduce or remove an effector function, a mutation to increase or decrease half-life of the antibody and a combination of the same. In one embodiment, where reference is made to the impact of a modification it may be demonstrated by comparison to an equivalent antibody lacking the modification. In some embodiments, antibodies of the invention may comprise multiple modifications, for example modifications which reduce or silence effector function may be present in addition to modifications which alter the half-life of the antibody and/or modifications which promote heterodimerisation. Therefore, any of the Fc regions disclosed herein may be further modified to comprise any of the Fc “silencing” mutations or strategies described above. The mutations may be symmetric or asymeteric. For example, in some embodiments, the Fc region comprises a first fragment of an immunoglobulin Fc region and a second fragment of an immunoglobulin Fc region containing the same Fc “silencing” mutations. In alternative embodiments, the first fragment of an immunoglobulin Fc region and the second fragment of an immunoglobulin Fc region may contain different Fc “silencing” mutations. For example, any of the Fc regions disclosed herein may additionally comprise the following mutations or any combination thereof: ^ L234A ^ L234F ^ L234S ^ L234D ^ L234R ^ L235A ^ L235E ^ L235T ^ L235R ^ P331S ^ P329G ^ G236R For example, any of the Fc regions disclosed herein may additionally comprise the following groups of mutations: ^ L234A/L235A ^ L234F/L235E/P331S ^ L234A/L235A/P329G ^ L234S/L235T/G236R ^ L234D/L235E ^ E233K/L234R/L235R Preferred hFc regions that may be incorporated into any of the bi-specific antigen binding molecules disclosed herein include: IgG1 hFc (L234A/L235A) EPKSSDKTHTCPPCPAPEAAGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKF NWYVDGV EVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQ PREPQVY TLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSK LTVDKSR WQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 653) IgG1 hFc (L234A/L235A/Y407T) EPKSSDKTHTCPPCPAPEAAGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKF NWYVDGV EVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQ PREPQVY TLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSK LTVDKSR WQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 654) IgG1 hFc (L234A/L235A/T366Y) EPKSSDKTHTCPPCPAPEAAGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKF NWYVDGV EVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQ PREPQVY TLPPSRDELTKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSK LTVDKSR WQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 655) IgG1 hFc (L234A/L235A/S239C/Y407T) EPKSSDKTHTCPPCPAPEAAGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKF NWYVDGV EVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQ PREPQVY TLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSK LTVDKSR WQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 656) IgG1 hFc (L234A/L235A/S239C/T366Y) EPKSSDKTHTCPPCPAPEAAGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKF NWYVDGV EVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQ PREPQVY TLPPSRDELTKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSK LTVDKSR WQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 657) IgG1 hFc (L234A/L235A/S239C/S442C/Y407T) EPKSSDKTHTCPPCPAPEAAGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKF NWYVDGV EVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQ PREPQVY TLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSK LTVDKSR WQQGNVFSCSVMHEALHNHYTQKSLCLSPGK (SEQ ID NO: 658) IgG1 hFc (L234A/L235A/S239C/S442C/T366Y) EPKSSDKTHTCPPCPAPEAAGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKF NWYVDGV EVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQ PREPQVY TLPPSRDELTKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSK LTVDKSR WQQGNVFSCSVMHEALHNHYTQKSLCLSPGK (SEQ ID NO: 659) IgG1 hFc (L234S/L235T/G236R) EPKSSDKTHTCPPCPAPESTRGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKF NWYVDGV EVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQ PREPQVY TLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSK LTVDKSR WQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 660) IgG1 hFc (L234S/L235T/G236R/Y407T) EPKSSDKTHTCPPCPAPESTRGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKF NWYVDGV EVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQ PREPQVY TLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSK LTVDKSR WQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 661) IgG1 hFc (L234S/L235T/G236R/T366Y) EPKSSDKTHTCPPCPAPESTRGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKF NWYVDGV EVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQ PREPQVY TLPPSRDELTKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSK LTVDKSR WQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 662) IgG1 hFc (L234S/L235T/G236R/S239C/Y407T) EPKSSDKTHTCPPCPAPESTRGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKF NWYVDGV EVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQ PREPQVY TLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSK LTVDKSR WQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 663) IgG1 hFc (L234S/L235T/G236R/S239C/T366Y) EPKSSDKTHTCPPCPAPESTRGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKF NWYVDGV EVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQ PREPQVY TLPPSRDELTKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSK LTVDKSR WQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 664) IgG1 hFc (L234S/L235T/G236R/S239C/S442C/Y407T) EPKSSDKTHTCPPCPAPESTRGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKF NWYVDGV EVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQ PREPQVY TLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSK LTVDKSR WQQGNVFSCSVMHEALHNHYTQKSLCLSPGK (SEQ ID NO: 665) IgG1 hFc (L234S/L235T/G236R/S239C/S442C/T366Y) EPKSSDKTHTCPPCPAPESTRGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKF NWYVDGV EVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQ PREPQVY TLPPSRDELTKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSK LTVDKSR WQQGNVFSCSVMHEALHNHYTQKSLCLSPGK (SEQ ID NO: 666) Preferred bi-specific heterodimers incorporating Fc “silencing” hFc mutations include: G3CP-P2A7 hFc(S239C) LALA G3CP hFc (L234A/L235A/S239C/T366Y) ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPEAAGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFS CSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 667) P2A7 hFc (L234A/L235A/S239C/Y407T) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHTC PPCPAPEAAGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHN AKTKPRE EQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPP SRDELTKN QVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGN VFSCSV MHEALHNHYTQKSLSLSPGK (SEQ ID NO: 668) G3CP-P2A7 hFc(S239C+S442C) LALA G3CP hFc (L234A/L235A/S239C/S442C/T366Y) ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPEAAGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFS CSVMHEALHNHYTQKSLCLSPGK (SEQ ID NO: 669) P2A7 hFc (L234A/L235A/S239C/S442C/Y407T) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHTC PPCPAPEAAGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHN AKTKPRE EQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPP SRDELTKN QVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGN VFSCSV MHEALHNHYTQKSLCLSPGK (SEQ ID NO: 670) G3CP-4D2 hFc(S239C) LALA G3CP hFc (L234A/L235A/S239C/T366Y) ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPEAAGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFS CSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 671) 4D2 hFc (L234A/L235A/S239C/Y407T) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSGGGGSGGGGSEPK SSDKT HTCPPCPAPEAAGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 672) G3CP-P2A7 hFc(S239C) STR G3CP hFc (L234S/L235T/G236R/S239C/T366Y) ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPESTRGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFS CSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 673) P2A7 hFc (L234S/L235T/G236R/S239C/Y407T) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHTC PPCPAPESTRGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHN AKTKPRE EQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPP SRDELTKN QVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGN VFSCSV MHEALHNHYTQKSLSLSPGK (SEQ ID NO: 674) G3CP-P2A7 hFc(S239C+S442C) STR G3CP hFc (L234S/L235T/G236R/S239C/S442C/T366Y) ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPESTRGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFS CSVMHEALHNHYTQKSLCLSPGK (SEQ ID NO: 675) P2A7 hFc (L234S/L235T/G236R/S239C/S442C/Y407T) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHTC PPCPAPESTRGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHN AKTKPRE EQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPP SRDELTKN QVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQGN VFSCSV MHEALHNHYTQKSLCLSPGK (SEQ ID NO: 676) G3CP-4D2 hFc(S239C) STR G3CP hFc (L234S/L235T/G236R/S239C/T366Y) ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPESTRGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFS CSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 677) 4D2 hFc (L234S/L235T/G236R/S239C/Y407T) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSGGGGSGGGGSEPK SSDKT HTCPPCPAPESTRGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 678) G3CP-4D2 hFc(S239C+S442C) STR G3CP hFc (L234S/L235T/G236R/S239C/S442C/T366Y) ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPESTRGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQ QGNVFS CSVMHEALHNHYTQKSLCLSPGK (SEQ ID NO: 679) 4D2 hFc (L234S/L235T/G236R/S239C/S442C/Y407T) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSGGGGSGGGGSEPK SSDKT HTCPPCPAPESTRGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLCLSPGK (SEQ ID NO: 680) Preferred embodiments are set out in the following numbered clauses 1. A bi-specific antigen binding molecule comprising: (i) a receptor tyrosine kinase-like orphan receptor 1 (ROR1) specific antigen binding molecule comprising an amino acid sequence represented by the formula (I): FW1-CDR1-FW2-HV2-FW3a-HV4-FW3b-CDR3-FW4 (I) wherein CDR3 is a CDR sequence having an amino acid sequence selected from the group consisting of YPWGAGAPYNVQWY (SEQ ID NO: 23), YPWGAGAPYLVQWY (SEQ ID NO: 20), YPWGAGAPWNVQWY (SEQ ID NO: 24), YPSGAGAPRPVQWY (SEQ ID NO:11), YPWGAGAPCLVQWY (SEQ ID NO: 12), YPWGAGAPRLVQWY (SEQ ID NO:13), YPWGAGAPRQVQWY (SEQ ID NO: 14), YPWGAGAPRSVQWY (SEQ ID NO: 15), YPWGAGAPSLVQWY (SEQ ID NO: 16), YPWGAGAPSNVQWY (SEQ ID NO: 17), YPWGAGAPSQVQWY (SEQ ID NO: 18), YPWGAGAPSSVQWY (SEQ ID NO: 19), YPWGAGAPWQVQWY (SEQ ID NO: 21), YPWGAGAPWSVQWY (SEQ ID NO: 22), and YPWGAGAPWLVQWY (SEQ ID NO: 10); CDR1 is a CDR sequence having an amino acid sequence selected from the group consisting of GANYGLAA (SEQ ID NO: 1), DANYGLAA (SEQ ID NO: 5), GANYDLSA (SEQ ID NO: 2), GANYGLSA (SEQ ID NO: 3), and GANYDLAA (SEQ ID NO: 4) FW1 is a framework region; FW2 is a framework region; HV2 is a hypervariable sequence having an amino acid sequence selected from the group consisting of SSNQERISIS (SEQ ID NO: 6), and SSNKERISIS (SEQ ID NO: 7); FW3a is a framework region; HV4 is a hypervariable sequence having an amino acid sequence selected from the group consisting of NKRTM (SEQ ID NO: 8) and NKGTM (SEQ ID NO: 9); FW3b is a framework region; FW4 is a framework region; wherein if CDR3 is YPWGAGAPWLVQWY (SEQ ID NO: 10) then CDR1 is selected from the group consisting of DANYGLAA (SEQ ID NO: 5), GANYGLSA (SEQ ID NO: 3) and GANYDLAA (SEQ ID NO: 4); and (ii) a protein tyrosine kinase 7 (PTK7) specific antigen binding molecule. 2. The bi-specific antigen binding molecule of clause 1 wherein: CDR3 is a CDR sequence having an amino acid sequence selected from the group consisting of YPWGAGAPYNVQWY (SEQ ID NO: 23), YPWGAGAPYLVQWY (SEQ ID NO: 20) and YPWGAGAPWNVQWY (SEQ ID NO: 24), and/or CDR1 is a CDR sequence having an amino acid sequence selected from the group consisting of GANYGLAA (SEQ ID NO: 1) and DANYGLAA (SEQ ID NO: 5). 3. The bi-specific antigen binding molecule of clause 1 or clause 2 wherein: CDR3 is a CDR sequence having an amino acid sequence according to YPWGAGAPYNVQWY (SEQ ID NO: 23). 4. The bi-specific antigen binding molecule of any preceding clause wherein: CDR3 is a CDR sequence having an amino acid sequence according to YPWGAGAPYNVQWY (SEQ ID NO: 23); CDR1 is a CDR sequence having an amino acid sequence according to GANYGLAA (SEQ ID NO: 1); HV2 is a hypervariable sequence having an amino acid sequence according to SSNQERISIS (SEQ ID NO: 6); and HV4 is a hypervariable sequence having an amino acid sequence according to NKRTM (SEQ ID NO: 8). 5. The bi-specific antigen binding molecule of any one of clauses 1 to 3 wherein: CDR3 is a CDR sequence having an amino acid sequence according to YPWGAGAPYNVQWY (SEQ ID NO: 23); CDR1 is a CDR sequence having an amino acid sequence according to DANYGLAA (SEQ ID NO: 5); HV2 is a hypervariable sequence having an amino acid sequence according to SSNKERISIS (SEQ ID NO: 7); and HV4 is a hypervariable sequence having an amino acid sequence according to NKGTM (SEQ ID NO: 9). 6. The bi-specific antigen binding molecule of any one of clauses 1 to 3 wherein: CDR3 is a CDR sequence having an amino acid sequence according to YPWGAGAPWLVQWY (SEQ ID NO: 10); CDR1 is a CDR sequence having an amino acid sequence according to DANYGLAA (SEQ ID NO: 5); HV2 is a hypervariable sequence having an amino acid sequence according to SSNKERISIS (SEQ ID NO: 7); and HV4 is a hypervariable sequence having an amino acid sequence according to NKGTM (SEQ ID NO: 9). 7. The bi-specific antigen binding molecule of any preceding clause further comprising an additional domain. 8. The bi-specific antigen binding molecule of clause 7 wherein the additional domain is an immunoglobulin, an immunoglobulin Fc region, an immunoglobulin Fab region, a single chain Fv (scFv), a diabody, a triabody, a tetrabody, a bispecific t-cell engager (BiTE), an intein, a VNAR domain, a single domain antibody (sdAb), a VH domain, or a scaffold protein. 9. The bi-specific antigen binding molecule of clause 8 wherein the additional domain is an Fc region. 10. The bi-specific antigen binding molecule of clause 9 wherein the additional domain is a human Fc region. 11. The bi-specific antigen binding molecule of clause 10 wherein the additional domain is hIgG1 (SEQ ID NO: 216). 12. The bi-specific antigen binding molecule of clause 10 wherein the additional domain is hIgG1 (S239C) (SEQ ID NO: 217). 13. The bi-specific antigen binding molecule of clause 10 wherein the additional domain is hIgG1 (S442c) (SEQ ID NO: 218). 14. The bi-specific antigen binding molecule of clause 10 wherein the additional domain is hIgG1 (S239C+S442C) (SEQ ID NO: 219). 15. The bi-specific antigen binding molecule of any preceding clause, further comprising a linker region between the ROR1-specific antigen binding molecule and PTK7-specific antigen binding molecule. 16. The bi-specific antigen binding molecule of clause 15, wherein the linker comprises [G ₄ S] _x , where x is 1, 2, 3, 4, 5, 5, 6, 7, 8, 9, or 10. 17. The bi-specific antigen binding molecule of clause 16, wherein the linker comprises [G4S]3, [G ₄ S] ₅ , or G ₄ S. 18. The bi-specific antigen binding molecule of clause 15, wherein the linker comprises PGVQPSPGGGGS (SEQ ID NO: 89) (Wobbe-G4S) or PGVQPAPGGGGS (SEQ ID NO: 90) (Wobbe- G ₄ S GM). 19. The bi-specific antigen binding molecule of any preceding clause, further comprising a C- or N- terminal tag sequence. 20. The bi-specific antigen binding molecule of clause 19, further comprising a C- terminal tag sequence selected from QASGAHHHHHHGAEFEQKLISEEDL (SEQ ID NO: 98), QACGAHHHHHHGAEFEQKLISEEDL (SEQ ID NO: 99), QACKAHHHHHHGAEFEQKLISEEDL (SEQ ID NO: 97), AAAHHHHHHGAEFEQKLISEEDL (SEQ ID NO: 100), ACAHHHHHHGAEFEQKLISEEDL (SEQ ID NO: 101), QASGAHHHHHH (SEQ ID NO: 102) QACGAHHHHHH (SEQ ID NO: 103), QACKAHHHHHH (SEQ ID NO: 104), AAAHHHHHH (SEQ ID NO: 105), ACAHHHHHH (SEQ ID NO: 106), QASGA (SEQ ID NO: 107), QACGA (SEQ ID NO: 108), QACKA (SEQ ID NO: 109), ACA (SEQ ID NO: 110), and SAPSA (SEQ ID NO: 111). 21. A bi-specific antigen binding molecule comprising: (i) a receptor tyrosine kinase-like orphan receptor 1 (ROR1) specific antigen binding molecule comprising an amino acid sequence represented by the formula (I): FW1-CDR1-FW2-HV2-FW3a-HV4-FW3b-CDR3-FW4 (I) wherein CDR1 is a CDR sequence having an amino acid sequence selected from the group consisting of GTRYGLYS (SEQ ID NO: 25), GTRYGLYSS (SEQ ID NO: 26), DTRYALYS (SEQ ID NO: 27), DTRYALYSS (SEQ ID NO: 28), GTKYGLYA (SEQ ID NO: 29), GTKYGLYAS (SEQ ID NO: 30) and DTSYGLYS (SEQ ID NO: 207); FW1 is a framework region; FW2 is a framework region; HV2 is a hypervariable sequence having an amino acid sequence selected from the group consisting of SSDEERISIS (SEQ ID NO: 31), STDEERISIG (SEQ ID NO: 32), SPNKDRMIIG (SEQ ID NO: 33), STDKERIIIG (SEQ ID NO: 34), and TTDWERMSIG (SEQ ID NO: 208); FW3a is a framework region; HV4 is a hypervariable sequence having an amino acid sequence selected from the group consisting of NKGTK (SEQ ID NO: 35), NKGSK (SEQ ID NO: 36), NNGTK (SEQ ID NO: 37), and NNRSK (SEQ ID NO: 38); FW3b is a framework region; CDR3 is a CDR sequence having an amino acid sequence according to REARHPWLRQWY (SEQ ID NO: 39); FW4 is a framework region; and (ii) a protein tyrosine kinase 7 (PTK7) specific antigen binding molecule. The bi-specific antigen binding molecule of any preceding clause, wherein FW1 is a framework region of from 20 to 28 amino acids; FW2 is a framework region of from 6 to 14 amino acids; FW3a is a framework region of from 6 to 10 amino acids; FW3b is a framework region of from 17 to 24 amino acids; and/or FW4 is a framework region of from 7 to 14 amino acids. 23. The bi-specific antigen binding molecule of clause 22, wherein FW1 has an amino acid sequence selected from the group consisting of: ASVNQTPRTATKETGESLTINCVVT (SEQ ID NO: 40), TRVDQSPSSLSASVGDRVTITCVLT (SEQ ID NO: 41) and ASVTQSPRSASKETGESLTITCRVT (SEQ ID NO: 42), or a functional variant of any thereof with a sequence identity of at least 45%; FW2 has an amino acid sequence according to TYWYRKNPG (SEQ ID NO: 43), or a functional variant of any thereof with a sequence identity of at least 45%; FW3a has an amino acid sequence selected from the group consisting of: GRYVESV (SEQ ID NO: 44) and GRYSESV (SEQ ID NO: 45), or a functional variant of any thereof with a sequence identity of at least 45%; FW3b has an amino acid sequence selected from the group consisting of: SFSLRIKDLTVADSATYYCKA (SEQ ID NO: 84), SFTLTISSLQPEDSATYYCRA (SEQ ID NO: 46) and SFSLRISSLTVEDSATYYCKA (SEQ ID NO: 47), or a functional variant of any thereof with a sequence identity of at least 45%; and/or FW4 has an amino acid sequence selected from the group consisting of: DGAGTVLTVN (SEQ ID NO: 48), DGAGTKVEIK (SEQ ID NO: 49) or DGQGTKLEVK (SEQ ID NO: 85) or a functional variant of any thereof with a sequence identity of at least 45%. 24. The bi-specific antigen binding molecule of clause 1, wherein the ROR1-specific antigen binding molecule comprises an amino acid sequence selected from the group consisting of: ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVN (SEQ ID NO: 50); TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPWLVQWY DGAGTKVEIK (SEQ ID NO: 51); ASVNQTPRTATKETGESLTINCVVTGANYDLSATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPSGAGAPRPVQWYDGAGTVLTVN (SEQ ID NO: 52); ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPCLVQWYDGAGTVLTVN (SEQ ID NO: 53); ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPRLVQWYDGAGTVLTVN (SEQ ID NO: 54); ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPRQVQWYDGAGTVLTVN (SEQ ID NO: 55);, ASVNQTPRTATKETGESLTINCVVTGANYGLSATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPRSVQWYDGAGTVLTVN (SEQ ID NO: 56); ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPRSVQWYDGAGTVLTVN (SEQ ID NO: 57); ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSLVQWYDGAGTVLTVN (SEQ ID NO: 58); ASVNQTPRTATKETGESLTINCVVTGANYGLSATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSNVQWYDGAGTVLTVN (SEQ ID NO: 59); ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSQVQWYDGAGTVLTVN (SEQ ID NO: 60); ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPSSVQWYDGAGTVLTVN (SEQ ID NO: 61); ASVNQTPRTATKETGESLTINCVVTGANYGLSATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPWLVQWYDGAGTVLTVN (SEQ ID NO: 62); ASVNQTPRTATKETGESLTINCVVTGANYDLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPWLVQWYDGAGTVLTVN (SEQ ID NO: 63); ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPWNVQWYDGAGTVLTVN (SEQ ID NO: 64); ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPWQVQWYDGAGTVLTVN (SEQ ID NO: 65); ASVNQTPRTATKETGESLTINCVVTGANYGLSATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPWQVQWYDGAGTVLTVN (SEQ ID NO: 66); ASVNQTPRTATKETGESLTINCVVTGANYDLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPWQVQWYDGAGTVLTVN (SEQ ID NO: 67); ASVNQTPRTATKETGESLTINCVVTGANYDLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPWSVQWYDGAGTVLTVN (SEQ ID NO: 68); ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPWSVQWYDGAGTVLTVN (SEQ ID NO: 69); and ASVNQTPRTATKETGESLTINCVVTGANYGLSATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPWSVQWYDGAGTVLTVN (SEQ ID NO: 70); or a functional variant having CDR1, HV2, HV4 and CDR2 sequences according to any thereof and having FW1, FW2, FW3a, FW3b and FW4 sequences having a combined sequence identity of at least 45% to the combined FW1, FW2, FW3a, FW3b and FW4 sequences of any thereof. 25. The bi-specific antigen binding molecule of clause 1, wherein the ROR1-specific antigen binding molecule comprises an amino acid sequence according to ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVN (SEQ ID NO: 50). 26. The bi-specific antigen binding molecule of clause 1, wherein the ROR1-specific antigen binding molecule comprises an amino acid sequence according to TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPWLVQWYDGAGTKVEIK (SEQ ID NO: 51). 27. The bi-specific antigen binding molecule of clause 1, wherein the ROR1-specific antigen binding molecule comprises an amino acid sequence selected from the group consisting of: TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIK (SEQ ID NO: 71); ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPYNVQWYDGQGTKLEVK (SEQ ID NO: 72); TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPSSVQWYDGAGTKVEIK (SEQ ID NO: 73); ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPSSVQWYDGQGTKLEVK (SEQ ID NO: 74); TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPRQVQWYDGAGTKVEIK (SEQ ID NO: 75); and ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPRQVQWYDGQGTKLEVK (SEQ ID NO: 76); or a functional variant having CDR1, HV2, HV4 and CDR2 sequences according to any thereof and having FW1, FW2, FW3a, FW3b and FW4 sequences having a combined sequence identity of at least 45% to the combined FW1, FW2, FW3a, FW3b and FW4 sequences of any thereof. 28. The bi-specific antigen binding molecule of clause 1, wherein the ROR1-specific antigen binding molecule comprises an amino acid sequence according to TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIK (SEQ ID NO: 71). 27. The bi-specific antigen binding molecule of clause 21, wherein the ROR1-specific antigen binding molecule comprises an amino acid sequence selected from the group consisting of: TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVN (SEQ ID NO: 206) TRVDQSPSSLSASVGDRVTITCVLTGTRYGLYSTYWYRKNPGSSDEERISISGRYSESVN KGTKSFTL TISSLQPEDSATYYCRAREARHPWLRQWYDGAGTKVEIK (SEQ ID NO: 77); TRVDQSPSSLSASVGDRVTITCVLTGTRYGLYSSTYWYRKNPGSSDEERISISGRYSESV NKGTKSFT LTISSLQPEDSATYYCRAREARHPWLRQWYDGAGTKVEIK (SEQ ID NO: 78); TRVDQSPSSLSASVGDRVTITCVLTDTRYALYSTYWYRKNPGSTDEERISIGGRYSESVN KGSKSFTL TISSLQPEDSATYYCRAREARHPWLRQWYDGAGTKVEIK (SEQ ID NO: 79); TRVDQSPSSLSASVGDRVTITCVLTDTRYALYSSTYWYRKNPGSTDEERISIGGRYSESV NKGSKSFT LTISSLQPEDSATYYCRAREARHPWLRQWYDGAGTKVEIK (SEQ ID NO: 80); TRVDQSPSSLSASVGDRVTITCVLTGTKYGLYATYWYRKNPGSPNKDRMIIGGRYSESVN NGTKSFTL TISSLQPEDSATYYCRAREARHPWLRQWYDGAGTKVEIK (SEQ ID NO: 81); TRVDQSPSSLSASVGDRVTITCVLTGTKYGLYASTYWYRKNPGSPNKDRMIIGGRYSESV NNGTKSF TLTISSLQPEDSATYYCRAREARHPWLRQWYDGAGTKVEIK (SEQ ID NO: 82); TRVDQSPSSLSASVGDRVTITCVLTGTKYGLYASTYWYRKNPGSTDKERIIIGGRYSESV NNRSKSFTL TISSLQPEDSATYYCRAREARHPWLRQWYDGAGTKVEIK (SEQ ID NO: 83); or a functional variant having CDR1, HV2, HV4 and CDR2 sequences according to any thereof and having FW1, FW2, FW3a, FW3b and FW4 sequences having a combined sequence identity of at least 45% to the combined FW1, FW2, FW3a, FW3b and FW4 sequences of any thereof. 28. The bi-specific antigen binding molecule of any preceding clause, wherein the ROR1-specific antigen binding molecule does not bind to receptor tyrosine kinase-like orphan receptor 2 (ROR2). 29. The bi-specific antigen binding molecule of any preceding clause, wherein the ROR1-specific antigen binding molecule binds to both human ROR1 and murine ROR1 (mROR1). 30. The bi-specific antigen binding molecule of any preceding clause, wherein the ROR1-specific antigen binding molecule binds to deglycosylated ROR1. 31. The bi-specific antigen binding molecule of any preceding clause, wherein the ROR1-specific antigen binding molecule is humanized. 32. The bi-specific antigen binding molecule of any one of clauses 1 to 30, wherein the ROR1- specific antigen binding molecule is de-immunized. 33. The bi-specific antigen binding molecule of any one of clauses 1 to 32, wherein the ROR1- specific antigen binding molecule is conjugated to a detectable label, dye, toxin, drug, pro-drug, radionuclide or biologically active molecule. 34. The bi-specific antigen binding molecule of any one of clauses 1 to 33, wherein the specific antigen binding molecule selectively interacts with ROR1 protein with an affinity constant of approximately 0.01 to 50 nM, preferably 0.1 to 30 nM, even more preferably 0.1 to 10 nM. 35. The bi-specific antigen binding molecule of any one of clauses 1 to 34, wherein the specific antigen binding molecule is capable of mediating killing of ROR1-expressing tumour cells. 36. The bi-specific antigen binding molecule of any one of clauses 1 to 34, wherein the specific antigen binding molecule is capable of inhibiting cancer cell proliferation. 37. The bi-specific antigen binding molecule of any one of clauses 1 to 34, wherein the specific antigen binding molecule is capable of being endocytosed upon binding to ROR1. 38. The bi-specific antigen binding molecule of any preceding clause, further comprising an additional domain. 39. The bi-specific antigen binding molecule of clause 38 wherein the additional domain is an immunoglobulin, an immunoglobulin Fc region, an immunoglobulin Fab region, a single chain Fv (scFv), a diabody, a triabody, a tetrabody, a bispecific t-cell engager (BiTE), an intein, a VNAR domain, a single domain antibody (sdAb), a VH domain, or a scaffold protein. 40. The bi-specific antigen binding molecule of clause 39 wherein the additional domain is an Fc region. 41. The bi-specific antigen binding molecule of clause 40 wherein the additional domain is a human Fc region. 42. The bi-specific antigen binding molecule of clause 41 wherein the additional domain is hIgG1 (SEQ ID NO: 216). 43. The bi-specific antigen binding molecule of clause 41 wherein the additional domain is hIgG1 (S239C) (SEQ ID NO: 217). 44. The bi-specific antigen binding molecule of clause 41 wherein the additional domain is hIgG1 (S442c) (SEQ ID NO: 218). 45. The bi-specific antigen binding molecule of clause 41 wherein the additional domain is hIgG1 (S239C+S442C) (SEQ ID NO: 219). 46. The bi-specific antigen binding molecule of any preceding clause, further comprising a linker region between the ROR1-specific antigen binding molecule and PTK7-specific antigen binding molecule. 47. The bi-specific antigen binding molecule of clause 46, wherein the linker comprises [G4S]x, where x is 1, 2, 3, 4, 5, 5, 6, 7, 8, 9, or 10. 48. The bi-specific antigen binding molecule of clause 47, wherein the linker comprises [G ₄ S] ₃ , [G4S]5, or G4S. 49. The bi-specific antigen binding molecule of clause 47, wherein the linker comprises PGVQPSPGGGGS (SEQ ID NO: 89) (Wobbe-G ₄ S) or PGVQPAPGGGGS (SEQ ID NO: 90) (Wobbe- G4S GM). 50. The bi-specific antigen binding molecule of any one of clauses 21 - 49, further comprising a C- or N- terminal tag sequence. 51. The bi-specific antigen binding molecule of clause 50, further comprising a C- terminal tag sequence selected from QASGAHHHHHHGAEFEQKLISEEDL (SEQ ID NO: 98), QACGAHHHHHHGAEFEQKLISEEDL (SEQ ID NO: 99), QACKAHHHHHHGAEFEQKLISEEDL (SEQ ID NO: 97), AAAHHHHHHGAEFEQKLISEEDL (SEQ ID NO: 100), ACAHHHHHHGAEFEQKLISEEDL (SEQ ID NO: 101), QASGAHHHHHH (SEQ ID NO: 102) QACGAHHHHHH (SEQ ID NO: 103), QACKAHHHHHH (SEQ ID NO: 104), AAAHHHHHH (SEQ ID NO: 105), ACAHHHHHH (SEQ ID NO: 106), QASGA (SEQ ID NO: 107), QACGA (SEQ ID NO: 108), QACKA (SEQ ID NO: 109), ACA (SEQ ID NO: 110), and SAPSA (SEQ ID NO: 111). 52. A recombinant fusion protein comprising a bi-specific antigen binding molecule as defined in any one of clauses 1 to 51. 53. The recombinant fusion protein as defined in clause 52, in which the bi-specific antigen binding molecule is fused to one or more biologically active proteins. 54. The recombinant fusion protein as defined in clause 53, wherein the bi-specific antigen binding molecule is fused to one or more biologically active proteins via one or more linker domains. 55. The recombinant fusion protein as defined in either clause 53 or 54, wherein at least one biologically active protein is an immunoglobin, an immunoglobulin Fc region, a fragment of an immunoglobulin Fc region, an Fc heavy chain, a CH2 region, a CH3 region, an immunoglobin Fab region, a Fab’, a Fv, a Fv-Fc, a single chain Fv (scFv), scFv-Fc, (scFv)2, a diabody, a triabody, a tetrabody, a bispecific t-cell engager, an intein, a VNAR domain, a single domain antibody (sdAb), a VH domain, or a scaffold protein. 56. The recombinant fusion protein as defined in clause 55, wherein the at least one biologically active protein is an immunoglobulin Fc region. 57. The recombinant fusion protein as defined in clause 56, wherein the at least one biologically active protein is a fragment of an immunoglobulin Fc region selected from the group consisting of an Fc heavy chain, a CH2 region and a CH3 region. 58. The recombinant fusion protein as defined in clause 57, wherein the fragment of an immunoglobulin Fc region is an Fc heavy chain, optionally wherein the Fc heavy chain is engineered to comprise one or more cysteine residues suitable for bioconjugation. 59. The recombinant fusion protein as defined in any one of clauses 57 to clause 58 wherein the fragment of an immunoglobulin Fc region is engineered to dimerize with a second fragment of an immunoglobulin Fc region. 60. The recombinant fusion protein as defined in any one of clauses 57 to 59 wherein the fragment of an immunoglobulin Fc region is engineered to dimerize with the second fragment of an immunoglobulin Fc region by a method selected from the group consisting of knobs-into-holes (Y-T), knobs-into-holes (CW-CSAV), CH3 charge pairing, Fab-arm exchange, SEED technology, BEATtechnology, HA-TF, ZW1 approach, Biclonic approach, EW-RVT and Triomab. 61. The recombinant fusion protein as defined in any one of clauses 57 to clause 60 wherein one or more residues of the fragment of the immunoglobulin Fc region comprises one or more amino acid substitution suitable for heterodimerization with a second fragment of an immunoglobulin Fc region, and wherein one or more residues of the second fragment of an immunoglobulin Fc region comprise one or more amino acid substitutions suitable for knobs-in-holes (KIH) dimerization with the first fragment of an immunoglobulin Fc region. 62. The recombinant fusion protein as defined in clause 61 wherein the one or more amino acid substitution is selected from the group consisting of T366Y, Y407T, S354C, T366W, Y349C, T366S, L368A and Y407V. 63. The recombinant fusion protein as defined in clause 61 or clause 62 wherein the one or more amino acid substitution is selected from the group consisting of T366Y and Y407T. 64. The recombinant fusion protein as defined in any one of clauses 55 to 63 or any clause dependent thereon, comprising a sequence according to any one or more of SEQ ID NO: 439 to 549. 65. A recombinant fusion protein dimer comprising: (a) a first recombinant fusion protein, wherein the first recombinant fusion protein comprises a receptor tyrosine kinase-like orphan receptor 1 (ROR1) specific antigen binding molecule comprising an amino acid sequence represented by the formula (I): FW1-CDR1-FW2-HV2-FW3a-HV4-FW3b-CDR3-FW4 (I) wherein CDR3 is a CDR sequence having an amino acid sequence selected from the group consisting of YPWGAGAPYNVQWY (SEQ ID NO: 23), YPWGAGAPYLVQWY (SEQ ID NO: 20), YPWGAGAPWNVQWY (SEQ ID NO: 24), YPSGAGAPRPVQWY (SEQ ID NO: 11), YPWGAGAPCLVQWY (SEQ ID NO: 12), YPWGAGAPRLVQWY (SEQ ID NO: 13), YPWGAGAPRQVQWY (SEQ ID NO: 14), YPWGAGAPRSVQWY (SEQ ID NO: 15), YPWGAGAPSLVQWY (SEQ ID NO: 16), YPWGAGAPSNVQWY (SEQ ID NO: 17), YPWGAGAPSQVQWY (SEQ ID NO: 18), YPWGAGAPSSVQWY (SEQ ID NO: 19), YPWGAGAPWQVQWY (SEQ ID NO: 21), YPWGAGAPWSVQWY (SEQ ID NO: 22), and YPWGAGAPWLVQWY (SEQ ID NO: 10); CDR1 is a CDR sequence having an amino acid sequence selected from the group consisting of GANYGLAA (SEQ ID NO: 1), DANYGLAA (SEQ ID NO: 5), GANYDLSA (SEQ ID NO: 2), GANYGLSA (SEQ ID NO: 3), and GANYDLAA (SEQ ID NO: 4) FW1 is a framework region; FW2 is a framework region; HV2 is a hypervariable sequence having an amino acid sequence selected from the group consisting of SSNQERISIS (SEQ ID NO: 6), and SSNKERISIS (SEQ ID NO: 7); FW3a is a framework region; HV4 is a hypervariable sequence having an amino acid sequence selected from the group consisting of NKRTM (SEQ ID NO: 8) and NKGTM (SEQ ID NO: 9); FW3b is a framework region; FW4 is a framework region; wherein if CDR3 is YPWGAGAPWLVQWY (SEQ ID NO: 10) then CDR1 is selected from the group consisting of DANYGLAA (SEQ ID NO: 5), GANYGLSA (SEQ ID NO: 3) and GANYDLAA (SEQ ID NO: 4), and wherein the first antigen binding molecule is fused to a first fragment of an immunoglobulin Fc region engineered to dimerize with a second fragment of an immunoglobulin Fc region;, and (b) a second recombinant fusion protein, wherein the second recombinant fusion protein comprises a protein tyrosine kinase 7 (PTK7) specific antigen binding molecule fused to a second fragment of an immunoglobulin Fc region engineered to dimerize with the first fragment of an immunoglobulin Fc region. 66. The recombinant fusion protein dimer as defined in clause 65, wherein the second fragment of an immunoglobulin Fc region selected from the group consisting of an Fc heavy chain, a CH2 region and a CH3 region. 67. The recombinant fusion protein dimer as defined in clause 66, wherein the second fragment of an immunoglobulin Fc region is an Fc heavy chain. 68. The recombinant fusion protein dimer as defined in any one of clauses 65 to 68 wherein the second fragment of an immunoglobulin Fc region is engineered to dimerize with the second fragment of an immunoglobulin Fc region by a method selected from the group consisting of knobs-into-holes (Y-T), knobs-into-holes (CW-CSAV), CH3 charge pairing, Fab-arm exchange, SEED technology, BEAT technology, HA-TF, ZW1 approach, Biclonic approach, EW-RVT and Triomab. 69. The recombinant fusion protein dimer as defined in any one of clauses 65 to clause 68 wherein one or more residues of the fragment of the immunoglobulin Fc region comprises one or more amino acid substitution suitable for knobs-in-holes (KIH) dimerization with a second fragment of an immunoglobulin Fc region comprising one or more corresponding amino acid mutation. 70. The recombinant fusion protein dimer as defined in clause 69 wherein the one or more amino acid substitution is selected from the group consisting of T366Y, Y407T, S354C, T366W, Y349C, T366S, L368A and Y407V. 71. The recombinant fusion protein dimer as defined in clause 69 or clause 70 wherein the one or more amino acid substitution is selected from the group consisting of T366Y and Y407T. 72. The recombinant fusion protein dimer as defined in any one of clauses 65 to 71 wherein the second antigen binding molecule is a ROR1 specific antigen binding molecule. 73. The recombinant fusion protein dimer according to any one of clauses 65 to 72 wherein the second specific antigen binding molecule is an immunoglobin, an immunoglobin Fab region, a Fab’, a Fv, a Fv-Fc, a single chain Fv (scFv), scFv-Fc, (scFv)2, a diabody, a triabody, a tetrabody, a bispecific t-cell engager, an intein, a VNAR domain, a single domain antibody (sdAb) or a VH domain. 74. The recombinant fusion protein dimer according to any one of clauses 65 or 73 wherein (a) the first recombinant fusion protein comprises a sequence according to SEQ ID NO: 50 (G3CP), SEQ ID NO: 61 (1H8) and SEQ ID NO: 71 (G3CP G4), and (b) the second recombinant fusion protein comprises a sequence according to SEQ ID NO: 210, SEQ ID NO: 211, SEQ ID NO: 212, SEQ ID NO: 213, SEQ ID NO: 214, or SEQ ID NO: 215. 75. The recombinant fusion protein dimer according to any one of clauses 65 or 73 wherein (a) the first recombinant fusion protein comprises G3CP-hFc, 1H8-hFc or G3CPG4-hFc, and (b) the second recombinant fusion protein comprises P2A7-hFc, E02-hFc, or 4D2-hFc. 76. The recombinant fusion protein dimer according to any one of clauses 65 or 73 wherein (a) the first recombinant fusion protein comprises G3CP-hFc (S239C & S442C), 1H8-hFc (S239C & S442C) or G3CPG4-hFc (S239C & S442C), and (b) the second recombinant fusion protein comprises P2A7-hFc (S239C & S442C), E02-hFc (S239C & S442C) or 4D2-hFc (S239C & S442C). 77. The recombinant fusion protein dimer according to any one of clauses 65 or 73 wherein (a) the first recombinant fusion protein comprises G3CP-hFc (S239C & S442C), 1H8-hFc (S239C & S442C) or G3CPG4-hFc (S239C & S442C), and (b) the second recombinant fusion protein comprises P2A7-hFc (S239C & S442C), E02-hFc (S239C & S442C) or 4D2-hFc (S239C & S442C). 78. The recombinant fusion protein dimer according to any one of clauses 65 or 73 wherein the recombinant fusion protein dimer is selected from the group consisting of: G3CP-hFc (S239C & S442C) and P2A7-hFc (S239C & S442C), G3CP-hFc (S239C & S442C) and E02-hFc (S239C & S442C), and G3CP-hFc (S239C & S442C) and 4D2-hFc (S239C & S442C); wherein the ROR1-specific binding molecule is fused to the hFc region via a [G ₄ S] ₃ linker or a G ₄ S linker and wherein (a) the hFc region fused to the ROR1-specific binding molecule comprises a T366Y substitution and the hFc region fused to the PTK7-specific binding molecule comprises a Y407T substitution, or (b) the hFc region fused to the ROR1-specific binding molecule comprises a Y407T substitution and the hFc region fused to the PTK7-specific binding molecule comprises a T366Y substitution. 79. The recombinant fusion protein dimer according to any one of clauses 65 or 73 wherein the recombinant fusion protein dimer is selected from the group consisting of: G3CPG4-hFc (S239C & S442C) and P2A7-hFc (S239C & S442C), G3CPG4-hFc (S239C & S442C) and E02-hFc (S239C & S442C), and G3CPG4-hFc (S239C & S442C) and 4D2-hFc (S239C & S442C); wherein the ROR1-specific binding molecule is fused to the hFc region via a [G ₄ S] ₃ linker or a G ₄ S linker and wherein (a) the hFc region fused to the ROR1-specific binding molecule comprises a T366Y substitution and the hFc region fused to the PTK7-specific binding molecule comprises a Y407T substitution, or (b) the hFc region fused to the ROR1-specific binding molecule comprises a Y407T substitution and the hFc region fused to the PTK7-specific binding molecule comprises a T366Y substitution. 80. The recombinant fusion protein dimer according to any one of clauses 65 or 73 wherein the recombinant fusion protein dimer is selected from the group consisting of: 1H8-hFc (S239C & S442C) and P2A7-hFc (S239C & S442C), 1H8-hFc (S239C & S442C) and E02-hFc (S239C & S442C), and 1H8-hFc (S239C & S442C) and 4D2-hFc (S239C & S442C); wherein the ROR1-specific binding molecule is fused to the hFc region via a [G ₄ S] ₃ linker or a G ₄ S linker and wherein (a) the hFc region fused to the ROR1-specific binding molecule comprises a T366Y substitution and the hFc region fused to the PTK7-specific binding molecule comprises a Y407T substitution, or (b) the hFc region fused to the ROR1-specific binding molecule comprises a Y407T substitution and the hFc region fused to the PTK7-specific binding molecule comprises a T366Y substitution. 81. The recombinant fusion protein of any one of clauses 52 to 64, or recombinant fusion protein dimer of any one of clauses 65 to 79, wherein the recombinant fusion protein comprises SEQ ID NO: 186 (G3CP-hFc), SEQ ID NO: 187 (G3CPG4-hFc), SEQ ID NO: 183 (1H8-hFc), SEQ ID NO: 184 (1H8 G4-hFc), SEQ ID NO: 185 (1H8 V15-hFc) and/or SEQ ID NO: 223 (P3A1-hFc). 82. A recombinant fusion protein dimer comprising: (a) a first recombinant fusion protein, wherein the first recombinant fusion protein comprises a receptor tyrosine kinase-like orphan receptor 1 (ROR1) specific antigen binding molecule comprising an amino acid sequence represented by the formula (I): FW1-CDR1-FW2-HV2-FW3a-HV4-FW3b-CDR3-FW4 (I) wherein CDR1 is a CDR sequence having an amino acid sequence selected from the group consisting of GTRYGLYS (SEQ ID NO: 25), GTRYGLYSS (SEQ ID NO: 26), DTRYALYS (SEQ ID NO: 27), DTRYALYSS (SEQ ID NO: 28), GTKYGLYA (SEQ ID NO: 29), GTKYGLYAS (SEQ ID NO: 30) and DTSYGLYS (SEQ ID NO: 207); FW1 is a framework region; FW2 is a framework region; HV2 is a hypervariable sequence having an amino acid sequence selected from the group consisting of SSDEERISIS (SEQ ID NO: 31), STDEERISIG (SEQ ID NO: 32), SPNKDRMIIG (SEQ ID NO: 33), STDKERIIIG (SEQ ID NO: 34) and TTDWERMSIG (SEQ ID NO: 208); FW3a is a framework region; HV4 is a hypervariable sequence having an amino acid sequence selected from the group consisting of NKGTK (SEQ ID NO: 35), NKGSK (SEQ ID NO: 36), NNGTK (SEQ ID NO: 37), NNRSK (SEQ ID NO: 38) and NKGAK (SEQ ID NO: 209); FW3b is a framework region; CDR3 is a CDR sequence having an amino acid sequence according to REARHPWLRQWY (SEQ ID NO: 39); FW4 is a framework region, and wherein the first antigen binding molecule is fused to a first fragment of an immunoglobulin Fc region engineered to dimerize with a second fragment of an immunoglobulin Fc region; and (b) a second recombinant fusion protein, wherein the second recombinant fusion protein comprises a protein tyrosine kinase (PTK7) specific antigen binding molecule fused to a second fragment of an immunoglobulin Fc region engineered to dimerize with the first fragment of an immunoglobulin Fc region. 83. The recombinant fusion protein dimer of clause 82 wherein: (a) the first recombinant fusion protein comprises P3A1, and (b) the second recombinant fusion protein comprises P2A7, E02, or 4D2. 84. The recombinant fusion protein dimer of clause 82 wherein: (a) the first recombinant fusion protein comprises P3A1-hFc, and (b) the second recombinant fusion protein comprises P2A7-hFc, E02-hFc or 4D2-hFc. 85. The recombinant fusion protein dimer of clause 82 wherein: (a) the first recombinant fusion protein comprises P3A1-hFc (S239C & S442C), and (b) the second recombinant fusion protein comprises P2A7-hFc (S239C & S442C), E02-hFc (S239C & S442C) or 4D2-hFc (S239C & S442C). 86. The recombinant fusion protein dimer of clause 82 wherein: (a) the first recombinant fusion protein comprises P3A1-hFc (S239C & S442C), and (b) the second recombinant fusion protein comprises P2A7-hFc (S239C & S442C), E02-hFc (S239C & S442C) or 4D2-hFc (S239C & S442C). 87. The recombinant fusion protein dimer of clause 82 wherein the recombinant fusion protein dimer may be selected from the group consisting of: P3A1-hFc (S239C & S442C) and P2A7-hFc (S239C & S442C), P3A1-hFc (S239C & S442C) and E02-hFc (S239C & S442C), and P3A1-hFc (S239C & S442C) and 4D2-hFc (S239C & S442C); wherein the ROR1-specific binding molecule is fused to the hFc region via a [G4S]3 linker or a G4S linker and wherein (a) the hFc region fused to the ROR1-specific binding molecule comprises a T366Y substitution and the hFc region fused to the PTK7-specific binding molecule comprises a Y407T substitution, or (b) the hFc region fused to the ROR1-specific binding molecule comprises a Y407T substitution and the hFc region fused to the PTK7-specific binding molecule comprises a T366Y substitution. 88. A bi-specific chimeric antigen receptor (CAR), comprising at least one bi-specific antigen binding molecule as defined in any one of clauses 1 to 32, fused or conjugated to at least one transmembrane region and at least one intracellular domain. 89. A cell comprising a chimeric antigen receptor according to clause 88, which cell is preferably an engineered T-cell. 90. A nucleic acid sequence comprising a polynucleotide sequence that encodes a bi-specific antigen binding molecule, recombinant fusion protein or chimeric antigen receptor according to any one of clauses 1 to 88. 91. A vector comprising a nucleic acid sequence as defined in clause 90, optionally further comprising one or more regulatory sequences. 92. A host cell comprising a vector as defined in clause 91. 93. A method for preparing a bi-specific antigen binding molecule, recombinant fusion protein or chimeric antigen receptor, comprising cultivating or maintaining a host cell comprising the polynucleotide of clause 90 under conditions such that said host cell produces the binding molecule, optionally further comprising isolating the binding molecule. 94. A pharmaceutical composition comprising the bi-specific antigen binding molecule, recombinant fusion protein or chimeric antigen receptor of any one of clauses 1 to 88. 95. The bi-specific antigen binding molecule, recombinant fusion protein or chimeric antigen receptor of any one of clauses 1 to 88, for use in therapy. 96. The bi-specific antigen binding molecule, recombinant fusion protein or chimeric antigen receptor of any one of clauses 1 to 88, for use in the treatment of cancer. 97. The bi-specific antigen binding molecule, recombinant fusion protein or chimeric antigen receptor of clause 96, wherein the cancer is a ROR1-positive cancer type and/or a PTK7-positive cancer type. 98. The bi-specific antigen binding molecule, recombinant fusion protein or chimeric antigen receptor for use of clause 96, wherein the cancer is selected from the group comprising blood cancers such as lymphomas and leukemias, chronic lymphocytic leukaemia (CLL), mantle cell lymphoma (MCL), B-cell acute lymphoblastic leukaemia (B-ALL), marginal zone lymphoma (MZL), non-Hodgkin lymphomas (NHL), acute myeloid leukemia (AML) and solid tumours including neuroblastoma, renal cancer, lung cancer, colon cancer, ovarian cancer, pancreatic cancer, breast cancer, skin cancer, uterine cancer, prostate cancer, thyroid cancer, Head and Neck cancer, bladder cancer, oesophageal cancer, stomach cancer or liver cancer. 99. The use of a bi-specific antigen binding molecule, recombinant fusion protein or chimeric antigen receptor of any one of clauses 1 to 87 in the manufacture of a medicament for the treatment of a disease in a patient in need thereof. 99. A method of treatment of a disease in a patient in need of treatment comprising administration to said patient of a therapeutically effective dosage of a bi-specific antigen binding molecule, recombinant fusion protein or chimeric antigen receptor of any one of clauses 1 to 87 or a pharmaceutical composition of clause 93. 100. The method of clause 99, wherein the disease is cancer. 101. The method of clause 100 wherein the cancer is a ROR1-positive cancer type and/or a PTK7- positive cancer type. 102. The method of clause 100, wherein the cancer is selected from the group consisting of blood cancers such as lymphomas and leukaemias, chronic lymphocytic leukaemia (CLL), mantle cell lymphoma (MCL), B-cell acute lymphoblastic leukaemia (B-ALL), marginal zone lymphoma (MZL), non-Hodgkin lymphomas (NHL), acute myeloid leukemia (AML) and solid tumours including neuroblastoma, renal cancer, lung cancer, colon cancer, ovarian cancer, pancreatic cancer, breast cancer, skin cancer, uterine cancer, prostate cancer, thyroid cancer, Head and Neck cancer, bladder cancer, oesophageal cancer, stomach cancer or liver cancer. 103. A method of assaying for the presence of a target analyte in a sample, comprising the addition of a detectably labelled bi-specific antigen binding molecule of any one of clauses 1 to 51 or a recombinant fusion protein of clause 52 to 64, or a recombinant fusion protein dimer of any one of clauses 65 to 87 to the sample and detecting the binding of the molecule to the target analyte. 104. A method of imaging a site of disease in a subject, comprising administration of a detectably labelled bi-specific antigen binding molecule as defined in any one of clauses 1 to 51 or a detectably labelled recombinant fusion protein of any one of clause 52 to 64, or a detectably labelled recombinant fusion protein dimer of any one of clauses 65 to 87 to a subject. 105. A method of diagnosis of a disease or medical condition in a subject comprising administration of a bi-specific antigen binding molecule as defined in any one of clauses 1 to 51 or a recombinant fusion protein of clause 52 to 64, or a recombinant fusion protein dimer of any one of clauses 65 to 87. 106. An antibody, antibody fragment or antigen-binding molecule that competes for binding to ROR1 with the bi-specific antigen binding molecule of any one of clauses 1 to 51. 107. A kit for diagnosing a subject suffering from cancer, or a pre-disposition thereto, or for providing a prognosis of the subject's condition, the kit comprising detection means for detecting the concentration of antigen present in a sample from a test subject, wherein the detection means comprises a bi-specific antigen binding molecule as defined in any one of clauses 1 to 51, a recombinant fusion protein as defined in any one of clauses 52 to 64, a recombinant fusion protein dimer as defined in any one of clauses 65 to 87, a CAR as defined in clause 88, or a nucleic acid as defined in clause 90, each being optionally derivatized, wherein presence of antigen in the sample suggests that the subject suffers from cancer. 108. The kit according to clause 107, wherein the antigen comprises ROR1 protein, more preferably an extracellular domain thereof. 109. The kit according to clause 107, wherein the kit is used to identify the presence or absence of ROR1-positive cells and/or PTK7-positive cells in the sample, or determine the concentration thereof in the sample. 110. The kit according to clause 107, wherein the kit comprises a positive control and/or a negative control against which the assay is compared. 111. The kit according to clause 107, wherein the kit further comprises a label which may be detected. 112. A method for diagnosing a subject suffering from cancer, or a pre-disposition thereto, or for providing a prognosis of the subject's condition, the method comprising detecting the concentration of antigen present in a sample obtained from a subject, wherein the detection is achieved using a bi- specific antigen binding molecule as defined in any one of clauses 1 to 51, a recombinant fusion protein as defined in any one of clauses 52 to 64, a recombinant fusion protein dimer as defined in any one of clauses 65 to 87, a CAR as defined in clause 88, or a nucleic acid sequence as defined in clause 90, each being optionally derivatized, and wherein presence of antigen in the sample suggests that the subject suffers from cancer. 113. A method of killing or inhibiting the growth of a cell expressing ROR1 and/or PTK7 in vitro or in a patient, which method comprises administering to the cell a pharmaceutically effective amount or dose of (i) bi-specific antigen binding molecule as defined in any one of clauses 1 to 51, a recombinant fusion protein as defined in any one of clauses 52 to 64, a recombinant fusion protein dimer as defined in any one of clauses 65 to 87, a nucleic acid as defined in clause 90, or the CAR or cell according to clause 88 or 89, or (ii) of a pharmaceutical composition according to clause 64. 114. The method of clause 113, wherein the cell expressing ROR1 and/or PTK7 is a cancer cell. 115. The method according to either clause 113 or 114, wherein the ROR1 is human ROR1. 116. A bi-specific antigen binding molecule comprising an amino acid sequence represented by the formula (II): X-FW1-CDR1-FW2-HV2-FW3a-HV4-FW3b-CDR3-FW4-Y (II) wherein FW1-CDR1-FW2-HV2-FW3a-HV4-FW3b-CDR3-FW4 is a ROR1-specific antigen binding molecule according to any one of clauses 1 to 25 X and Y are optional amino acid sequences wherein the ROR1-specific antigen binding molecule is conjugated to a second moiety and wherein the bi-specific antigen binding molecule further comprises a PTK7-specific antigen binding molecule. 117. The bi-specific antigen binding molecule of clause 116, wherein X or Y are individually either absent or selected from the group comprising an immunoglobulin, an immunoglobulin Fc region, an immunoglobulin Fab region, a Fab’, a Fv, a Fv-Fc, a single chain Fv (scFv), scFv-Fc, (scFv) ₂ , a diabody, a triabody, a tetrabody, a bispecific t-cell engager, an intein, a VNAR domain, a single domain antibody (sdAb), a VH domain, or a scaffold protein. 118. The bi-specific antigen binding molecule of clause 117, wherein X or Y are individually either absent or selected from the group comprising an immunoglobin, an immunoglobulin Fc region, a fragment of an immunoglobulin Fc region, an Fc heavy chain, a CH2 region, a CH3 region, an immunoglobin Fab region, a Fab’, a Fv, a Fv-Fc, a single chain Fv (scFv), scFv-Fc, (scFv)2, a diabody, a triabody, a tetrabody, a bispecific t-cell engager, an intein, a VNAR domain, a single domain antibody (sdAb), a VH domain, or a scaffold protein. 119. The bi-specific antigen binding molecule of clause 117 or clause 118, wherein X or Y are individually either absent or an immunoglobulin Fc region. 120. The bi-specific antigen binding molecule of clause 118, wherein X or Y are individually either absent or a fragment of an immunoglobulin Fc region selected from the group consisting of an Fc heavy chain, a CH2 region and a CH3 region. 121. The bi-specific antigen binding molecule of clause 120, wherein X or Y are individually either absent or a fragment of an immunoglobulin Fc region is an Fc heavy chain, optionally wherein the Fc heavy chain is engineered to comprise one or more cysteine residues suitable for bioconjugation. 122. The bi-specific antigen binding molecule of clause 120 or 121, wherein X or Y are individually either absent or a fragment of an immunoglobulin Fc region engineered to dimerize with a second fragment of an immunoglobulin Fc region. 123. The bi-specific antigen binding molecule of clause 120 to 122, wherein X or Y are individually either absent or a fragment of an immunoglobulin Fc region engineered to dimerize with the second fragment of an immunoglobulin Fc region by a method selected from the group consisting of knobs- into-holes (Y-T), knobs-into-holes (CW-CSAV), CH3 charge pairing, Fab-arm exchange, SEED technology, BEATtechnology, HA-TF, ZW1 approach, Biclonic approach, EW-RVT and Triomab. 124. The bi-specific antigen binding molecule of clause 108 to 123, wherein X or Y are individually either absent or a fragment of the immunoglobulin Fc region that comprises one or more amino acid substitution suitable for heterodimerization with a second fragment of an immunoglobulin Fc region comprising one or more corresponding amino acid mutation. 125. The bi-specific antigen binding molecule of clause 124 wherein the one or more amino acid substitution is selected from the group consisting of T366Y, Y407T, S354C, T366W, Y349C, T366S, L368A and Y407V. 126. The bi-specific antigen binding molecule of clause 124 or clause 125 wherein the one or more amino acid substitution is selected from the group consisting of T366Y and Y407T. 127. The bi-specific antigen binding molecule of any one of clause 116 to clause 126, wherein the conjugation is via a cysteine residue in the amino acid sequence of the specific antigen binding molecule. 128. The bi-specific antigen binding molecule of any one of clause 117 to clause 127, wherein the specific antigen binding molecule comprises SEQ ID NO: 178, SEQ ID NO: 179, SEQ ID NO: 180, SEQ ID NO: 181, or SEQ ID NO: 182 and/or SEQ ID NO: 224. 129. The bi-specific antigen binding molecule of any one of clause 117 to clause 127, wherein the specific antigen binding molecule comprises SEQ ID NO: 225, SEQ ID NO: 226, SEQ ID NO: 227, SEQ ID NO: 228, SEQ ID NO: 229, and/or SEQ ID NO: 230. 130. The bi-specific antigen binding molecule of any one of clause 117 to clause 127, wherein the specific antigen binding molecule comprises SEQ ID NO: 231, SEQ ID NO: 232, SEQ ID NO: 233, SEQ ID NO: 234, SEQ ID NO: 235, and/or SEQ ID NO: 236. 131. The bi-specific antigen binding molecule of any one of clause 117 to clause 127, wherein the specific antigen binding molecule comprises SEQ ID NO: 473, SEQ ID NO: 474, SEQ ID NO: 475, SEQ ID NO: 485, SEQ ID NO: 486 and/or SEQ ID NO: 487. 132. The bi-specific antigen binding molecule of any one of clause 117 to clause 127, wherein the specific antigen binding molecule comprises SEQ ID NO: 476, SEQ ID NO: 477, SEQ ID NO: 478, SEQ ID NO: 488, SEQ ID NO: 489 and/or SEQ ID NO: 490. 133. The bi-specific antigen binding molecule of any one of clause 117 to clause 127, wherein the specific antigen binding molecule comprises SEQ ID NO: 479, SEQ ID NO: 480, SEQ ID NO: 481, SEQ ID NO: 491, SEQ ID NO: 492 and/or SEQ ID NO: 493. 134. The bi-specific antigen binding molecule of any one of clause 117 to clause 127, wherein the specific antigen binding molecule comprises SEQ ID NO: 482, SEQ ID NO: 483, SEQ ID NO: 484, SEQ ID NO: 494, SEQ ID NO: 495 and/or SEQ ID NO: 496. 135. The bi-specific antigen binding molecule of any one of clauses 116 to 134, wherein the second moiety is selected from the group comprising an immunoglobulin or antibody, an immunoglobulin Fc region, an immunoglobulin Fab region, a Fab’, a Fv, a Fv-Fc, a single chain Fv (scFv), scFv-Fc, (scFv)2, a diabody, a triabody, a tetrabody, a bispecific t-cell engager, an intein, a VNAR domain, a single domain antibody (sdAb), a VH domain, or a scaffold protein. 136. The bi-specific antigen binding molecule of any one of clauses 116 to 134, wherein the second moiety is selected from the group comprising detectable label, dye, toxin, drug, pro-drug, radionuclide or biologically active molecule. 137. The bi-specific antigen binding molecule according to any one of clauses 116 to 134 or 136, wherein the second moiety is at least one toxin selected from the group comprising: • auristatins, • anthracyclines, preferably PNU-derived anthracyclines • maytansinoids, • amanitin derivatives, preferably α-amanitin derivatives • calicheamicins, • tubulysins • duocarmycins • radioisotopes - such as an alpha-emitting radionuclide, such as 227 Th and 225 Ac label • liposomes comprising a toxic payload, • protein toxins • taxanes • pyrrolbenzodiazepines and dimers thereof • indolinobenzodiazepine pseudodimers • spliceosome inhibitors • CDK11 inhibitors • Nicotinamide phosphoribosyltransferase inhibitors (NAMPTi) • Pyridinobenzodiazepines and dimers thereof • Cyclopropapyrroloindole (CPI), cyclopropabenzindole (CBI) or cyclopropathienoindole (CTI) and dimers thereof • Irinotecan or exatecan and their derivatives. 138. A target-binding molecule-drug conjugate, comprising (a) a bi-specific antigen binding molecule according to any one of clauses 1 to 51, or a recombinant fusion protein of any one of clauses 52 to 64, or a recombinant fusion protein dimer of any one of clauses 65 to 87, and (b) at least one toxin. 139. The target-binding molecule-drug conjugate of clause 138, wherein the toxin is selected from the group consisting of: auristatins, • anthracyclines, preferably PNU-derived anthracyclines • maytansinoids, • amanitin derivatives, preferably α-amanitin derivatives • calicheamicins, • tubulysins • duocarmycins • radioisotopes - such as an alpha-emitting radionuclide, such as 227 Th and 225 Ac label • liposomes comprising a toxic payload, • protein toxins • taxanes • pyrrolbenzodiazepines and dimers thereof • indolinobenzodiazepine pseudodimers • spliceosome inhibitors • CDK11 inhibitors • Nicotinamide phosphoribosyltransferase inhibitors (NAMPTi) • Pyridinobenzodiazepines and dimers thereof • Cyclopropapyrroloindole (CPI), cyclopropabenzindole (CBI) or cyclopropathienoindole (CTI) and dimers thereof • Irinotecan or exatecan and their derivatives. 140. The target-binding molecule-drug conjugate of clause 130 or clause 139, comprising (b) an anthracycline (PNU) derivative, wherein the target-binding molecule-drug conjugate has the structure of formula (III): wherein [X] is an optional spacer selected from the group comprising substituted or unsubstituted alkyl groups, substituted or unsubstituted heteroalkyl groups, substituted or unsubstituted aryl groups, substituted or unsubstituted heteroaryl groups, one or more heteroatoms, polyethylene glycol, or a combination thereof; [L1] and [L2] are optional linkers selected from the group consisting of valine (Val), citrulline (Cit), alanine (Ala), asparagine (Asn), a peptide, -(CH2)n-, -(CH2CH2O)n-, p-aminobenzyloxycarbonyl (PAB), Val-Cit-PAB, Val-Ala-PAB, Ala-Ala-Asn-PAB, Val-Ala, Asn-Ala, any amino acid except glycine, and combinations thereof; and Y comprises a bi-specific antigen binding molecule according to any one of clauses 1 to 51, or a recombinant fusion protein of any one of clauses 52 to 64, or a recombinant fusion protein dimer of any one of clauses 65 to 87. 141. The target-binding molecule-drug conjugate of clause 140, wherein the target-binding molecule-drug conjugate of formula (III) comprises [L1], [L2] or [L1] and [L2]. 142. The target-binding molecule-drug conjugate of any one of clauses 140 to 141, wherein [L2] is p-aminobenzyloxycarbonyl (PAB) or alanine. 143. The target-binding molecule-drug conjugate of clause 140, wherein the target-binding molecule-drug conjugate has a structure selected from: 144. The target-binding molecule-drug conjugate of clause 140, comprising (b) an anthracycline (PNU) derivative, wherein the target-binding molecule-drug conjugate has the structure of formula (IV): wherein [X] is an optional spacer selected from the group comprising substituted or unsubstituted alkyl groups, substituted or unsubstituted heteroalkyl groups, substituted or unsubstituted aryl groups, substituted or unsubstituted heteroaryl groups, one or more heteroatoms, polyethylene glycol, or a combination thereof; [Z] is a linker derived from a reactive group used to conjugate the anthracycline (PNU) derivative and the target-binding molecule; and Y comprises a bi-specific antigen binding molecule according to any one of clauses 1 to 51, or a recombinant fusion protein of any one of clauses 52 to 64, or a recombinant fusion protein dimer of any one of clauses 65 to 87. 145. The target-binding molecule-drug conjugate of clause 144, wherein [Z] is selected from the group consisting of a disulphide bond, an amide bond, an oxime bond, a hydrazone bond, a thioether bond, a 1, 2, 3 triazole and polyGly. 146. The target-binding molecule-drug conjugate of any one of clauses 140 to 143 or 144 to 145, wherein [X] is selected from the group comprising polyethylene glycol, ’ represents the point of attachment to the rest of the molecule and wherein [R] is an optional spacer selected from the group comprising substituted or unsubstituted alkyl groups, substituted or unsubstituted heteroalkyl groups, substituted or unsubstituted aryl groups, substituted or unsubstituted heteroaryl groups, one or more heteroatoms, polyethylene glycol, or a combination thereof. 147. The target-binding molecule-drug conjugate of any one of clauses 140 to 143 or 144 to 145, wherein [X] is polyethylene glycol. 148. The target-binding molecule-drug conjugate of any one of clauses 140 to 147, wherein the target-binding molecule is a protein and the anthracycline (PNU) derivative is conjugated to a thiol- containing amino acid residue in the amino acid sequence of the protein or wherein the PNU derivative is conjugated via a thiol moiety incorporated by chemical modification at the N-terminus or C-terminus of the amino acid sequence of the protein. 149. The target-binding molecule-drug conjugate according to any one of clauses 140 to 148, wherein Y comprises a ROR1 specific antigen binding molecule according to any one of clauses 1 to 25 conjugated to the PNU derivative via a human immunoglobulin Fc region or fragment thereof. 150. The target-binding molecule-drug conjugate of clause 130 or clause 139 wherein the toxin is an auristatin and (b) is an a MMAE derivative, wherein the target-binding molecule-drug conjugate has the structure of formula (VI): [X] is an optional spacer selected from the group comprising substituted or unsubstituted alkyl groups, substituted or unsubstituted heteroalkyl groups, substituted or unsubstituted aryl groups, substituted or unsubstituted heteroaryl groups, one or more heteroatoms, polyethylene glycol, or a combination thereof; [L1] and [L2] are optional linkers selected from the group consisting of valine (Val), citrulline (Cit), alanine (Ala), asparagine (Asn), a peptide, -(CH2)n-, -(CH2CH2O)n-, p-aminobenzyloxycarbonyl (PAB), Val-Cit-PAB, Val-Ala-PAB, Ala-Ala-Asn-PAB, Val-Ala, Asn-Ala, any amino acid except glycine, and combinations thereof; and Y comprises a bi-specific antigen binding molecule according to any one of clauses 1 to 51, or a recombinant fusion protein of any one of clauses 52 to 64, or a recombinant fusion protein dimer of any one of clauses 65 to 87. 151. The target-binding molecule-drug conjugate of claim 150 wherein the toxin is an auristatin and (b) is an a MMAE derivative, wherein the target-binding molecule-drug conjugate has the structure of formula (VIII): (VIII). 152. The bi-specific antigen binding molecule of any one of clauses 1 to 51 or the recombinant fusion protein of any one of clauses 52 to 64, or the recombinant fusion protein dimer of any one of clauses 65 to 87, wherein the PTK7-specific binding molecule is an immunoglobulin, an immunoglobulin Fab region, a single chain Fv (scFv), a diabody, a triabody, a tetrabody, a bispecific t- cell engager (BiTE), an intein, a VNAR domain, a single domain antibody (sdAb), a VH domain, or a scaffold protein. 153. The bi-specific antigen binding molecule, the recombinant fusion protein, or the recombinant fusion protein dimer of clause 152 wherein the PTK7-specific binding molecule is VNAR domain. 154. The bi-specific antigen binding molecule, the recombinant fusion protein, or the recombinant fusion protein dimer of clause 153 wherein the PTK7-specific binding molecule is a VNAR domain according to SEQ ID NO: 440. 155. The bi-specific antigen binding molecule, the recombinant fusion protein, or the recombinant fusion protein dimer of clause 153 wherein the PTK7-specific binding molecule is a VNAR domain according to SEQ ID NO: 452. 155. The bi-specific antigen binding molecule, the recombinant fusion protein, or the recombinant fusion protein dimer of clause 153 wherein the PTK7-specific binding molecule is a VNAR domain according to SEQ ID NO: 453. The present invention will be further understood by reference to the following examples. EXAMPLES EXAMPLE 1 – Generation of the anti-ROR1 VNAR B1 loop library sequences B1 protein library design. To gain a better understanding of the interaction between B1 and ROR1, we solved the crystal structure of B1 in complex with the ROR1 Ig domain (data not shown). This crystal structure informed which positions to change in the protein library that was expressed and screened. We had previously noted that mutation of B1 Tryptophan residues at positions 88 and 94 to Alanine (standard alanine scanning approach) caused loss of function or expression of the protein. From the crystal structure it was observed that these residues in the CDR3 loop appear to be important for ROR1 binding. A B1 loop library was therefore designed to modify the biophysical properties of the protein through changing selected positions within the CDR1 and CDR3 regions. The set of mutations made at each particular loop position was informed from the structural analysis of the B1:ROR1 complex, with a view to changing the biophysical properties whilst maintaining structural integrity and high affinity binding. Library construction Sequence and loop library design of B1 are shown in Figure 1. Library was synthesised by controlled mutagenesis of CDR1 and CDR3. Residues 30, 32, 88, 94 and 95 located within CDR loops were randomised. Libraries construction. B1 loop library DNA was amplified by PCR using specific primers to introduce SfiI restriction sites for cloning into pEDV1 phagemid vector. Library DNA ligated into pEDV1 was transformed into electrocompetent TG1 E.coli (Lucigen). The library size was calculated to be 8 x 104. 84 single clones were picked and sequenced as a quality control of the library. One sequence has been found to be WT B1 clone. In total 70 unique clones based on CDR1 and CDR3 diversity were identified. These sequences contain a C-terminal HisMyc tag to enable purification by IMAC chromatography and assessment of ROR1 binding by ELISA and flow cytometry Screening of the library for ROR1 specific VNAR sequences As B1 binds to both human and mouse ROR1, recombinant human and mouse ROR1-Fc protein was used for screening CDR loop library. In total 928 clones were expressed in 96 well format; periplasmic fractions were extracted and binding to ROR1 analysed in ELISA.23 unique sequences additional to B1 WT sequence which binds to ROR1 were found. Expression of ROR1 VNAR binders 23 clones were expressed in TG1 E.coli bacteria and IMAC purified using Ni-NTA Sepharose. Proteins were dialysed to PBS pH 7.4, absorbance Abs280 was measured and concentrations calculated. Yields obtained were in a range of 1.5 and 9 mg/L. Purity of proteins was analysed by SDS-PAGE. Binding to human and mouse ROR1 by ELISA for the different loop variants is summarised in Table 5. Methods Library synthesis CDR loops library was synthetized by GeneArt Gene Synthesis according with provided design. Library subcloning into pEDV1 PCR amplification of 11.4 ng (10 µl) of synthetised library was performed in the total reaction volume 1 ml using Phusion High-Fidelity PCR Master Mix and the following primers: 280: 5’-CTACCGTGGCCCAGGCGGCC-3’ (SEQ ID NO: 133) 287: 5’-GGTGATGGTGGGCCCCTGAGGCCT-3’ (SEQ ID NO: 134) Amplicons were purified with Promega PCR purification Kit, digested with SfiI and ligated into pEDV1 vector opened with SfiI restriction enzyme as well. Ligation performed at ratio 1:3 (0.54 µg vector ligated with 1.62 µg library DNA). Screening of CDR loop library: Periplasmic expression of single clones in 96 well format and binding ELISA 1. Inoculate Greiner 96 deep-well plate containing 1ml 2xTY/0.1% glucose/100µg/µl Amp. Grow for 5h at 37 °C, 180 rpm in incubation chamber until faintly turbid. 2. Induced with 110 µl/well 1 mM IPTG in 2xTY/Amp (final concentration of IPTG =100µM); same shaking speed at 28°C overnight. 3. Spin cultures for 15 min at 4°C and 3500 rpm. Decant supernatant and tap dry on paper towels. 4. Add 250 µl/well ice-cold TES buffer (50 mM Tris/HCl, pH8.0/1 mM EDTA, pH8.0/20% Sucrose) to the pellets. Vortex. 5. Add 250 µl 1:5 diluted in water TES buffer (ice-cold). Keep on ice (or in the ridge) for 30 min. Spin as above. Keep supernatants on ice until ready to use. ELISA 1. Coat 96 well plates with 1 µg/ml of huROR1-Fc, mouse ROR1-Fc, human ROR2-Fc or HSA and incubated overnight at 4°C. 2. Wash plates 3xPBST. 3. Block coated plates with 200µl/well 4% MPBS. Incubate for 1h at room temperature. 4. Wash 3xPBST. 5. Incubate plates with 100 µl/well of peri-prep for 1 h at room temperature. 6. Add 100 µl of anti-His-HRP (1:1000 in PBST) and incubate 1h at room temperature. 7. Wash 2xPBST and 2x PBS. 8. Add 100 µl/well of TMB substrate. Stop reaction with 50 µl/well 1M H2SO4. Large scale expression and purification of ROR1 VNAR binders 1. Inoculate clones from glycerol stock into 20 ml of 2xTY/0.1% glucose/100 µg/µl Amp. Grow overnight at 37°C shaking at 250 rpm in incubation chamber. 2. Dilute the overnight culture 1:50 in TB + phosphate salt + 1% glucose +100 µg/ml Amp media (10 ml o/n culture into 500ml media; 450 ml TB + 50 ml phosphate salt) and incubate at 37°C with vigorous shaking (250 rpm) all day or as long as possible. 3. Pellet the cells by centrifugation at 4,000 x g for 15 min at 20°C. 4. Re-suspend the cells in the same volume of TB + phosphate salt + 1% glucose +100 µ g/ml Amp media and incubate at 30°C overnight with shaking. 5. Pellet the cells by centrifugation at 4,000 x g for 15 min at 20°C and re-suspend the cells in the same volume of TB + phosphate salt +100 µg/ml Amp media (NO GLUCOSE). Add IPTG to a final conc. of 1 mM IPTG. Incubate at 30°C for 4-5 h with shaking. 6. Collect the cells by centrifugation at 4500 x g for 20 min [the pellet could be frozen at this point at -20°C] 7. Re-suspend the pellet in 10% culture volume ice-cold TES buffer (50 ml for 500 ml culture) and shake gently on ice for 15 min. 8. Add an equal volume ice-cold 5 mM MgSO4 (for 2.5 mM final concentration of MgSO4) and continue shaking gently on ice for a further 15 min. 9. Pellet the suspension by centrifugation at 8000 x g for 30 min at 4°C. Supernatant contains released periplasmic proteins. 10. Add 10xPBS (pH 7.4) [final conc. of 1xPBS] to peri-prep extract prior to IMAC purification. Immobilised Metal Affinity Chromatography (IMAC) purification 1. Add 2-3 ml Nickel-resin (His Pur Ni-NTA Resin, Thermo Fisher#88222) to 100 ml osmotic shock solution (periplasmic extract) and incubated on roller for 1 hour at room temperature. 2. Allow periplasmic extract to pass through the column (Poly prep chromatography columns 10 ml, Bio-Rad# 7321010) 3. Wash the resin with 50 - 100ml PBS. 4. Eluted protein with 5 x 1 ml 500 mM imidazole (pH 8). 5. Dialyze eluates in 3x5 liters PBS with agitation in dialysis cassette (Slide A Lyzer Dialysis cassette 7.000 MWCO, Thermo Fisher#66707) 6. Analyse proteins by SDS-PAGE. Concentrations of purified proteins were determined from absorbance at 280 nm using the theoretical extinction coefficient predicted from the amino acid sequence. All proteins were characterised by reducing and non-reducing SDS PAGE analysis and mass spectrometry. The formation of the desired disulphide bond was confirmed by mass spectrometry methods. Size exclusion chromatography Loop engineered variants were assessed by size exclusion chromatography. The monomericity and biophysical properties of B1 loop variants were assessed by size-exclusion chromatography (SEC) using an analytical SEC column (Superdex 7510/300 GL). Chromatography was carried out in PBS pH 7.4. The elution volume on SEC can be a measure of the relative hydrophobicity of the different proteins. With increased elution volume, as a result of interactions with the column matrix, an indication of increasing hydrophobicity. The SEC elution volumes run under identical conditions are shown in Table 5. Binding to human and mouse ROR1 by BLI Binding kinetics were determined using the Biolayer Interferometry (BLI) Octet K2 system (ForteBio). Human or mouse ROR1-hFc fusion proteins (extracelluar domains) were immobilised in sodium acetate pH5 buffer to COOH2 chips or AR2G sensors using amine coupling. VNARs were tested at various concentrations and the Ka (M ^-1 s ^-1 ), Kd (s ^-1 ) and KD (nM) values were determined using Octet Data Analysis High Throughput software (ForteBio) for Biolayer Interferometry. Table 5. summarise the BLI data for the affinity of these molecules for human and mouse ROR1.

₁ R O _* R _* ^*/ _{* * * * *} s ^t _n ai _r a _v 1 _{) y} r R M _{2 2 2 2 6 a} O ⁿ ( 1 ¹ ₁ ^{2 3} _. ^{6 9 9} _. ^{6 8 4} _. ⁶ _. ^{9 4} _. ^{6 0 5 3 6 6} _. ^{9 r R} D ^{. .} ₀ ^{. 2} ₅ ^. ₄ ^. _{5 5 5 2 6 0 4 1 6 7 b h 2 8 1 1} ^{9 . . 3 2 . 3 . . . . . . 1 . i} l K _{4 9 3 8 2 1 1 0 1 0 0 2 9 2 0 1 0} p _o o _{l 1} B ^f _{o ) n l} o _{i 9 4 6 5 6 2 8 2 7 9 4 5 5} C ^m ₍ ^{7 7 1 7 6 1 7 5 5 4 3 9 2} _{6 7 7 8} t _a ^E _{T .} 7 _. 7 _. 9 _. 8 _. 8 _. 8 _. 7 _. 8 ⁸ _. 8 _. 8 _. 5 _{. .} ⁶ _. ⁴ _. ⁶ _. ⁷ _. ⁶ _. ⁰ _. ⁵ _. s _{i S} R _{2 1 2 1 1 1 1 1 1 1 1 2} ¹ ₂ ⁵ ₂ ⁵ ₂ ³ ₂ ⁰ ₂ ⁰ ₂ ⁶ ₂ ⁸ ₁ ⁰ ₂ r _e ^t _c a _r a _h C ^: _{5 e} ^l _e 1 _{P P P 5} ² ₁ C _P ⁰ _{P P P P} C _{P b} ^m _{2 5 1} ^{C C} _{5 4 9 8} ¹ ₁ ^C _{6 1} C C C _{1 0} ^{C a} _a ¹ _B ^{E E B} ₃ ^{G G F G H} ₉ ^{B F 6 2 6 G 1} _{3 T} N _{1 1 1} C _{2 1} G _{2 1 1} G D _{1 1 E F B 1 A} G Binding of loop variant VNARs to cell-surface ROR1 by flow cytometry Loop variant VNARs were re expressed using intein technology. For expression as intein fusions, DNA encoding VNARs was optimised for E. coli expression (GeneArt, Thermo) and cloned in frame into an intein expression vector. This results in a gene encoding the VNAR protein of interest fused to an engineered intein domain which in turn is fused to a chitin binding domain (CBD) to enable purification on a chitin column. Transformed E.coli cells were grown in 1L shaker flasks until OD600nm = ~0.6, cold shocked 4 °C for 2 hours then protein expression induced with 0.5mM IPTG at 18 °C overnight. Cells were lysed by sonication in lysis buffer (50mM sodium phosphate pH7.4, 0.5M NaCl, 15% glycerol, 0.5mM EDTA, 0.1% Sarkosyl, 1mM AEBSF) and centrifuged to remove cell debris. VNAR intein fusion protein was purified from clarified cell lysate by immobilising on chitin beads (NEB, S6651). Beads were washed extensively with lysis buffer followed by cleavage buffer (50mM sodium phosphate pH6.9, 200mM NaCl) and VNARs released from the beads by overnight chemical cleavage in 400mM dioxyamine, or O,O’- 1,3-propanediylbishydroxylamine, or 100mM cysteine or cysteamine to generate the corresponding C- terminal aminoxy, C-terminal cysteine or C-terminal thiol derivative of the VNARs. Cleaved VNAR supernatant was then further purified by SEC (Superdex7526/60 GE healthcare) and / or IMAC (HisTrap HP, GE Healthcare). Concentrations were determined from absorbance at 280 nm using the theoretical extinction coefficient predicted from the amino acid sequence. All proteins were characterised by reducing and non-reducing SDS PAGE analysis and mass spectrometry. The formation of the desired disulphide bond in the VNAR domain was confirmed by mass spectrometry methods. These C-terminal HisMyc tagged proteins were then assessed for ROR1 cell-surface binding by flow cytometry Cell surface binding of test agents to hROR1 was characterized in different cell lines (A549 and A427) and the resulting KDapp values determined. Adherent cancer cells were detached from tissue culture flasks by incubating with 0.1% EDTA/PBS solution at 37 °C for ~10 minutes or until cells detached easily. Cells were re-suspended in ice-cold PBS/2%FCS in 15ml tubes and centrifuged at 1500rpm for 5 mins at 4 °C. Supernatant was removed and the cell pellet re-suspended in PBS/2%FCS. A cell count was performed using a Z1 Coulter Particle Counter (Beckman Coulter) or Chemometec Nucleocounter NC-202 and 5 x 10^5 cells were aliquoted per test sample into a 96 well plate. Cells were incubated with 100µl of test agents at a range of concentrations, plus controls for 1hr on ice. The sample plate was centrifuged at 2000 rpm for 5mins. The supernatant was removed and a wash performed by re-suspending the cell pellets in 0.25mL of ice-cold PBS/2%FCS using a multichannel pipette. Samples were again centrifuged at 2000rpm for 5min at 4°C. Supernatant was removed and two further washes performed as described. After the final wash and centrifugation step, excess liquid was removed by blotting the plate on tissue paper. Binding of VNARs was determined by adding 100µl of anti-x6His tag Ab (Abcam) per cell pellet sample as appropriate and incubated on ice for 30mins. Wash steps were performed as described previously. PE-anti-mouse antibody (JIR) was used to detect binding of the VNAR (His6 tagged) agents and corresponding drug-conjugates by incubating with the appropriate samples for 30min on ice in the dark. Wash steps were performed as described previously. All cell pellets were finally re-suspended in 0.3ml of ice-cold PBS/2%FCS and left on ice in the dark prior to analysis on a Cytek Biosciences Guava EasyCyte HT or Thermo Fisher Attune NxT flow cytometer. As shown in Figure 2 and Figure 3, the loop library variants bind to the ROR1 ^hi human cancer cell-line A549 but not to the ROR1 ^low human cancer cell-line A427.2V is a control VNAR sequence, derived from a naïve VNAR library, so is representative of this protein class but has no known target. EXAMPLE 2 - Humanisation and further engineering of B1 loop library variants Humanised sequence derivatives of three lead ROR1 binding B1 loop library VNARs were generated using two different strategies. Humanised sequences were designed based on the human germ line Vκ1 sequence, DPK-9. For example, in P3A1 V1 the framework regions 1, 3 and 4 of the VNAR were mutated to align with the framework regions of DPK-9. The second strategy involved grafting the binding loops of the ROR1 binding VNARs onto a previously humanised VNAR framework (Kovalenko et al JBC 2013288(24) 17408-17419; WO2013/167883). But with further positions engineered based on the structure of the VNAR B1 in complex with the ROR1 Ig domain. Additional sites of engineering include amino acid changes in the CDR1, HV2 and HV4 regions of the protein. Similarly, a humanised variant of B1 was developed using this approach, which accordingly contains amino acid changes in its CDR1, HV2 and HV4 regions as well as the framework regions. So B1G4 is, by de facto, a loop library derivative of B1 or a loop library variant of humanised variants of B1 whereby the CDR1, HV2, HV4 and CDR3 sequences are the same as in the parental protein. Examples of humanised / grafted loop library VNAR sequences are below: G3CP G4 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIK (SEQ ID NO: 71) G3CP V15 ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPYNVQWYDGQGTKLEVK (SEQ ID NO: 72) 1H8 G4 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPSSVQWYDGAGTKVEIK (SEQ ID NO: 73) 1H8 V15 ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPSSVQWYDGQGTKLEVK (SEQ ID NO: 74) C3CP G4 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPRQVQWYDGAGTKVEIK (SEQ ID NO: 75) C3CPV15 ASVTQSPRSASKETGESLTITCRVTGANYGLAATYWYRKNPGSSNQERISISGRYSESVN KRTMSFSL RISSLTVEDSATYYCKAYPWGAGAPRQVQWYDGQGTKLEVK (SEQ ID NO: 76) B1G4 TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPWLVQWYDGAGTKVEIK (SEQ ID NO: 51). DNA encoding the humanised constructs was codon optimised for expression in E. coli and synthesised by GeneArt (Thermo). All humanised sequences were generated with the following C terminal His ₆ tag: QASGAHHHHHH (SEQ ID NO: 102) G4 sequences were made without an additional C-terminal tag. DNA encoding these proteins was sub cloned into the intein expression vectors, expressed in E. coli and purified as described previously in “Typical method for expression of VNAR intein fusion proteins” section. Humanised ROR1 binding VNAR variants demonstrated high affinity binding to human ROR1 by BLI, good thermal stability and little evidence of aggregation by SEC. BLI was performed as described previously using human ROR1 ECD – Fc immobilised to the chip surface. SEC was performed as previously described. Thermal stability assays used Applied Biosystems StepOne Real Time PCR system with the Protein Thermal Shift™ dye kit (Thermo). The assay mix was set up so that the protein was at a final concentration of 20 ^M in 20 ^L.5 ^L of Thermal Shift™ buffer was added alongside 2.5 uL 8x Thermal Shift™ Dye. Assays were run using the StepOne software and data analysed using Protein Thermal Shift™ software. All data are from first derivative analysis. BLI data for hROR1 binding and thermal stability by protein thermal shift is shown in Table 6. Table 6: Thermal stability and hROR1 binding data for humanised VNAR loop variants Either grafting the HV and CDR loops of G3CP, 1H8 and C3CP onto a humanised VNAR framework coupled with additional mutations in the CDR1, HV2 and HV4 regions or substituting VNAR framework sequences with regions from the human DPK-9 sequence, yielded substantially engineered proteins that are stable, monomeric and maintain high affinity binding to hROR1. EXAMPLE 3 – Generation of the anti-ROR1 VNAR P3A1 G1 loop library sequences Library design P3A1 G1 is a humanised version of the ROR1 binding VNAR P3A1. The P3A1 G1 loop library was designed to improve ROR1 binding affinity of this humanised variant via randomisation of CDR1, HV2 and HV4 regions without any changes within frameworks. Choice of mutations was made based on the data analysis of VNAR sequences from Squalus acanthus. Sequence of P3A1 G1 and library design are shown in Figure 4. Library was synthesised by controlled mutagenesis of CDR1, HV2 and HV4. Residues 26-33, 44-52 and 61-65 located within CDR1, HV2 and HV4 loops respectively were changed to selected amino acids as specified in Fig.4 resulting in total library diversity of 8.2x10 ⁶ combinations. Libraries construction. P3A1 G1 library DNA was amplified by PCR using specific primers to introduce SfiI restriction sites for cloning into pEDV1 phagemid vector. This introduces an additional Ser residue into CD1. Library DNA ligated into pEDV1 was transformed into electrocompetent TG1 E.coli (Lucigen). The library size was calculated to be 2 x 10 ⁸ .192 single clones were picked and sequenced as a quality control of the library. Screening of P3A1 G1 library for antigen specific VNAR sequences. Recombinant human ROR1 protein was used for selections and screening of the P3A1 G1 library. Two strategies were utilised to isolate ROR1 specific binders: selections on biotinylated antigen immobilised on pre-decorated streptavidin-coated beads and selections with antigen directly immobilised to the immunotube. Selection on pre-decorated with biotinylated antigen beads involved 3 rounds of panning with low stringency in first and second rounds (3xPBST and 3xPBS washes for both rounds, 100 nM and 10 nM of biotinylated huROR1 for round 1 and 2 respectively), but high stringency for third round (10xPBST and 10xPBS washes, 0.5 nM of biotinylated huROR1). Selection on immunotubes consists of 2 rounds of panning with constant antigen concentration of 2 ng/ml. Following the selection process, outputs were screened for antigen-specific binding by monoclonal phage and periplasmic extract ELISAs against human or mouse ROR1.95% of monoclonal phage displaying the VNARs were specific to human and mouse ROR1 from selections with antigen directly immobilised to the immunotube and 4% for selections on biotinylated antigen immobilised on pre-decorated streptavidin-coated beads. In total 9 unique sequences from each selection campaign were expressed and analysed for binding and selectivity (Table 7 and 8).

W ^R _{L L P .} ^{W W} _P ^W H ^s _d ^{W W} _{P P} H ^W _{P P} R A ^a _{P e} H H H R R R H H R E ^b R ^{A A} _E R ^{A R d A A} _{E E E} ^{A R} _{E E A e} ^{R R} _{A A} ^{R R} Y _T D H S _A ^E _n H E ^{o W} _{Y L} ^Y _{T L} ^Y _T D ^Y _T D ^Y _{T L} ^Y _T D Y _L ^S _I ^s H L _n ^{H T} D D o ⁱ _{A S} ^{E Y} _E ^S _S ^E _E ^{S E} S _E ^{S E} _E ^S D S ^E _{E L} ^S _I ^Y _L ^S _I ^Y _L ^S _{S I} ^Y _L ^S _{I A} ^{E Y} _{E S L} ^S _I ^{F S} _I G _{K t} G Y ^L Q ^{c S L G L A} _K ^{L G} _{K L} ^{L G L A} _K K ^E _e ^l _A ^G _{K K e Y} Q _Y Q _Y Q _Y Q _{Y K} Q Q _{Y T F} G _T ^E _A ^{s Q : S} g _T ^{E K} _T ^R _T ^E _F ^G _T ^E _F ^K _T ^K _T ^E _F D _F ^{E D} _F ^{E D E} _A ^{G E D} _F ^{D E L} _V G ^m _o ^a t _T ^E _{A T} ^E _{A T T A T T A} G G ^E _A CH ^r f ^l H _a ^L _V G ^L _V G ^L _V ^{L L L} G n H _{V V} G _V C C C CH C CH T _I H ^d _i H H H H H H T H _e ^{t T} _I H ^T _I H ^T _I H ^T _I H ^T _I H ^T _I H VH _a ^{l m} _r ^T H ^T _V H ^T _V H ^T _V H ^T _V H ^T _V H R D ^H _o ^e t A ^s _{i - V} H H H H H H C RH RH R R RH R D D ^H D ^{H H G} _s D ^{H H} _{A A} D ^H D _{A V} G S ^t _{n g} ^G _A ^G _{V A} ^G _V G ^G _V G ^G _{V A} ^G G S _{A A} ^a _i ⁿ _{i V} G G S ^{S S} _A ^{S S} _A G _V S ^{S S} _A S Q L ^K _I ^r _a ^d _u ^S _A ^S _{A) A} ^S _{A A} Q _A Q _A ^S _{A A} Q S ^{v l} _c ^S Q ⁵ ₃ ^S Q ^{S K} _I ^{S K S} Q ^{S K} S ^E _L ¹ _{L L L I L L I V} ^{p P} _o ⁿ _{i -} ^{S K} _{I :} ^K _I ^K _{I S S} ^K _T ^o _l ^E O ^S _S ^S _S ^E _V ^S _S ^E _V ^S _S ^S _S ^E _V e ^P _V ^{N E P} _V ^{E P K P K P} _V ^{P K} Q ^G _{1 c} n _T ^K _T ^D I _S ^K _{T S T S T S} ^K _{T S T} D _{A V} G Q Q Q ^G Q ^G Q Q ^G G _e R ₁ ^{u D G} _A ^{Q D G} _A ^D _A ^D _A ^{D G} _A ^D _{A T} ^D _{q V E V V} G _V G _{V V} G Y ^A ₃ ^e _S ^R _T G ^S ( ^R G ^{R D R D R} G ^{R D P} D _T D _{T Y T Y T} D _{T Y S} ^{: .} _{8 7 e} n ¹ 9 3 5 F ^l A _b ^o _l ^D _{I A} ^{C a 3} _{1 A S} ^C _{A S} ^E _A ^F _A ^F _{A T} C _{e P} G N ^. ₁ N ^. ₆ N ^S _. N ^S _. N ^S _{. S} ^I _{S T} ^I _T ^I _{T S} ^{I L L L} _{T T T T} ^{L F F F} _{T S S S} ^{F K K K} _{S S T T} ^{K G} _K ^G _S G N _K ^{G N} _{K V} ^{N N} V _V ^{N S S S} _{V E E E} ^{S S} _Y ^S _E S _Y ^S R _Y R _Y R G G R G ^S _I G G ^I I _I ^G I _I ^S _I G ^I R ^I _S ^I _I E ₎ R E ³ ₇ ^E ₎ R K ₎ ^E _E ^{5 D} ₎ 1 ^S _: D ⁴ ₇ D ¹ _E 3 D ₇ D ⁶ ₇ ¹ _{2 S} O ^S _S ¹ _: ^S _{: S} O ^T _S ¹ _: G ^{N G} O ^{G N G} O P ^D _P ^N _P ^D _P ^{N N} _{I K} ^{N Q} _K ^{D I N} _{I K} ^{Q N} _K ^{D I R} _{Y E} S ^R _Y ^Q _E ^R _{Y E} S ^R _Y ^Q _E W ₍ W ^S ₍ W ₍ ^{S Y} _L Y _L ^Y _L W _{( T} D _{T T} D ^Y _{T L} S ^{E S} D ^{S E S} D S _{E S} ^E _{S E A} ^{E Y S} _{I E} ^{Y S} _{I E L} ^{L Y G} _{K L} ^S _{I L} ^{Y S} YQ ^G _Y ^{L L} K ^G _{K L I Y} Q ^{A L} _K G _T ^E _F ^K Q _Y R ^E _F ^R Q G _T ^E _T ^E A ^G _{F T T} ^E _F L _T ^{E G} _T ^E _A ^D _{T V} G ^L _{V A} ^{L E} VG ^L _A H G _V G C C CH TH H ^T H H CH I _I H ^T _I H ^{T T} _I H VH ^T _V H H H H ^T _V ^T _V H RH R H H R RH D ^H _A D D ^H _A D G _V G ^{G H} V _A G ^H _A G ^G _V ^G _V G S ^S A _A ^S _A ^S _A ^{S S} A _A ^S _A ^{S S} Q L ^K _I ^S Q _{A L} Q ^S _L ^K _I ^S Q S ^{E K} _I E ^E _L ^K _{I S V} ^S _S ^S V _{S V} ^S _S ^{E P K K K} _{V S T} ^P _S ^P _{S T} ^{P G} _{T S} ^K Q _A Q Q ^G Q _T D _V G ^D _V ^G _A ^D _{A V} G ^{D G} _{A T Y} ^R _T G _V R ^D D ^R _T ^D _Y ^R _T G D . ₅ ⁰ ₁ ^. ₃ ^{. A} _{A S} ^D _{4 A} ^S _. ^E _{A S} ^F _{A S} Expression of ROR1 P3A1 G1 loop variants Clones were expressed in TG1 E.coli bacteria and the resulting C-terminally HisMyc-tagged proteins were purified by IMAC using Ni-NTA Sepharose. Proteins were dialysed to PBS pH 7.4, absorbance Abs280 was measured and concentrations calculated. Yields obtained were in a range of 0.5 and 6.5 mg/L. Purity of proteins was analysed by SDS-PAGE. All proteins were characterised by reducing and non-reducing SDS PAGE analysis and mass spectrometry. The formation of the desired disulphide bond was confirmed by mass spectrometry methods. Binding of P3A1 G1 loop variants to hROR1 by ELISA The binding of P3A1 G1 loop variants to human ROR1 was initially assessed by ELISA. In brief, ELISA method as follows. Wells coated with 100ng of ROR1-hFc antigen and incubated, covered, at room temperature for 2hr. Plates washed 3x 400ul per well with PBST (PBS + 0.05% Tween 20 (v/v)), then blocked with 4% skimmed milk powder (w/v) in PBST for 1 hour at 37°C. Plates washed as before plus additional wash in PBS alone. HisMyc-tagged binding proteins were diluted in 4% milk PBST and incubated overnight at 4 °C. Plates washed 3x with PBST, 3x PBS and binding detected using appropriate secondary detection antibody in 4% milk PBST, room temperature 1 hour. Secondary antibodies used include: Anti-c-Myc, HRP (Invitrogen #R951-25) Mouse anti-polyHis, HRP (Sigma #A7058) Plates washed 3x with PBST. 100µL TMB substrate (Thermo #34029) added and reaction allowed to proceed at r.t. for 10mins. 100 µL of 2M H ₂ SO ₄ added to quench the reaction. Plate centrifuged briefly before absorbance at 450nm read on a CLARIOstar plate reader (BMG Labtech). Figure 5 shows the relative binding of different variants to human ROR1 with sequences NAG8.S, AF7.S, NAC6.S and AE3.S showing the strongest signal for binding. The same ELISA method was also used to compare binding of variants NAG8.S, AF7.S, NAC6.S and AE3.S to human ROR1 with that of the parental P3A1 G1 sequence. The dose response data shown in Figure 6 shows that these loop library sequences bind stronger to human ROR1 than the parental P3A1 G1 protein. Characterisation of mouse ROR1 and ROR2 binding of P3A1 G1 loop variants by ELISA A selection of P3A1 G1 loop variants were further characterised for binding to mouse ROR1 and human ROR2 by ELISA. The same ELISA procedure was employed as described above but with either mROR1-hFc or hROR2-hFc coated on the plates. None of the variants tested bound to human ROR2. Of the variants that were tested, NAC6.S and AE3.S bound to mouse ROR1 Expression of P3A1 G1 loop library variants as intein fusion proteins P3A1 G1 loop variant VNARs NAG8.S, NAC6.S and AE3.S were re-expressed using intein technology but with a Ser deletion from the CDR1 loop. Expression as intein fusions was performed as described above with either a His tag QACKAHHHHHHG (SEQ ID NO: 163) or HisMyc tag QACKAHHHHHHGAEFEQKLISEEDLG (SEQ ID NO: 164) incorporated at the C-terminus of the VNAR domain. Following expression and capture on chitin beads the intein VNARs were released from the beads by overnight chemical cleavage in 400mM dioxyamine, or O,O’-1,3-propanediylbishydroxylamine, or 100mM cysteine or cysteamine to generate the corresponding C-terminal aminoxy, C-terminal cysteine or C-terminal thiol derivative of the VNARs. Cleaved VNAR supernatant was then further purified by SEC (Superdex7526/60 GE healthcare) and / or IMAC (HisTrap HP, GE Healthcare) to give the proteins NAG8, NAC6 and AE3. Concentrations were determined from absorbance at 280 nm using the theoretical extinction coefficient predicted from the amino acid sequence. All proteins were characterised by reducing and non-reducing SDS PAGE analysis and mass spectrometry. The formation of the desired disulphide bond in the VNAR domain was confirmed by mass spectrometry methods. These C-terminal HisMyc or His tagged proteins were then further assessed for ROR1 binding by BLI, thermal stability and biophysical properties by SEC, Binding to human and mouse ROR1 by BLI Binding kinetics were determined using the Biolayer Interferometry (BLI) Octet K2 system (ForteBio). Human or mouse ROR1-hFc fusion proteins (extracelluar domains) were immobilised in sodium acetate pH5 buffer to COOH2 chips or AR2G sensors using amine coupling. VNARs were tested at various concentrations and the Ka (M ^-1 s ^-1 ), Kd (s ^-1 ) and K _D (nM) values were determined using Octet Data Analysis High Throughput software (ForteBio) for Biolayer Interferometry. Binding parameters are shown in Table 9. Thermal stability assays Thermal stability assays used Applied Biosystems StepOne Real Time PCR system with the Protein Thermal Shift™ dye kit (Thermo). The assay mix was set up so that the protein was at a final concentration of 20 µM in 20 µL in PBS pH 7.4.2.5 µL 8x Thermal Shift™ Dye was added. Assays were run using the StepOne software and data analysed using Protein Thermal Shift™ software. All data are from first derivative analysis with the Tm values detailed in Table 9. Size exclusion chromatography The monomericity and biophysical properties of P3A1 loop variants were assessed by size-exclusion chromatography (SEC) using an analytical SEC column (Superdex 75 increase 10/300 GL). Chromatography was carried out in PBS pH 7.4. The % monomericity and SEC elution volumes run under identical conditions are shown in Table 9. Table 9: Summary of ROR1 binding and physical properties of P3A1 G1 variants NAG8, NAC6 and AE3 EXAMPLE 4 – VNAR Reformatting as multimers ROR1 binding loop variant VNARs were successfully reformatted into hetero dimers and trimers by genetic fusion using different GlySer based linkers to generate bi-specific binders, ROR1 bi-paratopic binders and ROR1 bi-paratopic bi-specific binders. Bispecific binders Several bi-specific VNAR-based binders were developed by combining ROR1 loop-variant VNAR binders with the humanised VNAR BA11, which binds with high affinity to serum albumins, using a PGVQPSPGGGGGS (SEQ ID NO: 96) linker Proteins were expressed with a C-terminal tag QACKAHHHHHHGAEFEQKLISEEDL (SEQ ID NO: 97) or QACKAHHHHHH (SEQ ID NO: 104) to aid purification and characterisation. This tag also contains a single cysteine residue to facilitate site-selective bioconjugation of payloads to the proteins using thiol mediated chemical coupling strategies Binding kinetics were determined using Biolayer interferometry (K2 Octet instrument / Pall ForteBio) as previously described. For BLI experiments ROR1-hFc, (extracellular domain) and HSA were immobilised in sodium acetate pH5 buffer to AR2G sensors using amine coupling. VNAR-based molecules were tested at various concentrations and the Ka (M ^-1 s ^-1 ), Kd (s ^-1 ) and KD (nM) values were determined using the Octet data analysis HT software (Pall ForteBio). Binding kinetics for hROR1 binding were also performed with saturating levels of HSA (200 nM) in the baseline, association and dissociation conditions. Binding to the ROR1hi A549 cancer-cell lines was determined by flow cytometry. A dose response was performed and the KDapp for cell-surface ROR1 binder determined using the change in median fluorescence intensity (background corrected) as a function of VNAR concentration. The characterisation of these bi-specific VNARs is shown in Table 10. Table 10: Characterisation of bi-specific proteins containing ROR1 VNAR loop library variants Bi-specific VNAR binders were further modified through conjugation to the single cysteine residue in the C-terminal tag. Bi-paratopic binders Several ROR1 bi-paratopic binders were developed combining different ROR1 loop-variant VNAR binders with or without additional insertion of the serum albumin binding humanised VNAR BA11. The VNAR domains were joined together using a PGVQPAPGGGGS (SEQ ID NO: 90) linker and proteins were expressed with a C-terminal tag QACKAHHHHHHGAEFEQKLISEEDL (SEQ ID NO: 97) or QACKAHHHHHH (SEQ ID NO: 104) to aid purification and characterisation. This tag also contains a single cysteine residue to facilitate site-selective bioconjugation of payloads to the proteins using thiol mediated chemical coupling strategies Binding kinetics were determined using Biolayer interferometry (K2 Octet instrument / Pall ForteBio) as previously described. For BLI experiments ROR1-hFc, (extracelluar domain) was immobilised in sodium acetate pH5 buffer to AR2G sensors using amine coupling. VNAR-based molecules were tested at various concentrations and the Ka (M ^-1 s ^-1 ), Kd (s ^-1 ) and KD (nM) values were determined using the Octet data analysis HT software (Pall ForteBio). The characterisation of these bi-specific VNARs is shown in Table 11. Table 11: Characterisation of bi-paratopic proteins containing ROR1 VNAR loop library variants Bi-paratopic binders show increased affinity for binding ROR1 as compared to the individual ROR1 binding monomers. The constructs containing BA11 are examples of bi-paratopic bi-specific protein binders. Furthermore, several bi-specific and bi-paratopic VNAR-based binders were developed by combining ROR1 loop-variant VNAR binders with the humanised VNAR BA11 or by combining different ROR1 loop-variant VNAR binders using a PGVQPCPGGGGGS (SEQ ID NO: 177) linker. This linker sequence also contains a single cysteine residue to facilitate site-selective bioconjugation of payloads to the proteins, in this linker, using thiol mediated chemical coupling strategies. Proteins were expressed with a C-terminal tag QASGAHHHHHH (SEQ ID NO: 102) or QACKAHHHHHH (SEQ ID NO: 104) to aid purification and characterisation. Table 12: Characterisation of bi-specific and bi-paratopic proteins containing ROR1 VNAR loop library variants with cysteine containing linker sequences Bi-specific VNAR binders were further modified through conjugation to the single cysteine residue in the linker sequence. Prior to conjugation, 20 equivalents of TCEP were added to the bispecific proteins to remove cysteine/glutathione capping of the linker thiol. After incubation at room temperature for one hour the TCEP was removed by purification on a HiTrap SP cation exchange chromatography column (Cytiva). To load onto the column the protein was diluted three-fold in 50 mM Na Phosphate buffer pH 6.0. The protein was then eluted by an increasing gradient of elution buffer consisting of 50 nM Na phosphate pH 6.0, 1 M NaCl. To conjugate, 4 equivalents of a maleimide containing payload was added and left to incubate at room temperature for 1 hour. Free payload was then removed by cation exchange using the same protocol as above. Table 13: Characterisation of bi-specific and bi-paratopic protein drug conjugates containing ROR1 VNAR loop library variants with cysteine containing linker sequences Without being bound by any particular theory, it is expected that conjugate yields can be improved by increasing scale of production and by employing optimised purification processes. EXAMPLE 5 – VNAR Reformatting as Fc fusion proteins VNAR Fc Fusion Proteins Fusion of proteins to an Fc domain can improve protein solubility and stability, markedly increase plasma half-life and improve overall therapeutic effectiveness. A human IgG1 Fc sequence is shown below and further examples are shown in Figure 7. Human IgG1 Fc (hFc) EPKSSDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKF NWYVDGV EVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQ PREPQVY TLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSK LTVDKSR WQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 145) VNAR loop variants were genetically fused via standard [G4S]3 linkers to engineered hIgG1 Fc domains that contained a cysteine substitution in the hIgG1 Fc sequence, S239C (EU numbering). The VNAR Fc fusion proteins were transiently expressed as secreted protein in CHO K1 cells and purified from the media using MabSelect™ SuRe™ (Evitria, Switzerland). Purified proteins were exchanged into PBS pH 7.4 or PBS + 100 mM Arg pH 7.4 and analysed by SEC (AdvanceBio, Agilent, running buffer DPBS pH 7.4), SDS PAGE and mass spectrometry to confirm sequence and protein integrity. Binding kinetics were determined using a Pioneer Surface Plasmon Resonance (SPR) instrument (SensiQ/Pall ForteBio), or the Biolayer Interferometry (BLI) Octet K2 system (ForteBio). ROR1-hFc fusion proteins (extracelluar domains) were immobilised in sodium acetate pH5 buffer to COOH2 chips or AR2G sensors using amine coupling. VNAR-Fc molecules were tested at various concentrations and the Ka (M ^-1 s ^-1 ), Kd (s ^-1 ) and KDapp (nM) values were determined using Octet Data Analysis High Throughput software (ForteBio) for Biolayer Interferometry. Alternatively, the kinetic parameters for binding were determined by immobilising the VNAR-hFc fusion onto AHC sensors. Human ROR1 (ECD) was tested at various concentrations and the Ka (M ^-1 s ^-1 ), Kd (s ^-1 ) and KD (nM) values for 1:1 binding were determined using Octet Data Analysis High Throughput software (ForteBio) for Biolayer Interferometry. ROR12A2 mAb (Biolegend) was included as a control for positive/negative binding to ROR1.2V is a control VNAR sequence, derived from a naïve VNAR library, so is representative of this protein class but has no known target. SEC analysis was performed as described previously. The data, summarised in Table 14, demonstrates advantageous properties of the loop library hFc variants versus the parental B1-hFc protein. Binding of the VNAR-Fc fusions to ROR1 on the surface of cancer cell lines was measured by flow cytometry using the methods described previously, with binding of VNAR-hFc fusion molecules determined by adding 100µL of PE-anti-human antibody (JIR) and incubating on ice for 30mins. KDapp values were calculated from the increase in fluorescence intensity as a function of VNAR-hFc concentration. Figure 8 shows the binding of different VNAR-Fc fusions to the ROR1 ^hi A549 lung adenocarcinoma cells.

^s _e ^l _u c _e ^l _o m _c F ^e _{s h} - _L ^{/ e} _{5 g h} ^{t 1} f _V ^{m o} ₈ ⁰ ₀ ⁵ _. ⁹ ₁ ⁹ _{. 5} D o _r p _h - ^d _{4 L} ^/ e G _g g _{n P} ^{m a 0} _{5 h} ^C _{3 0} ^{2 0} _. ^{9 5} 2 c _x G ¹ _{. >} ⁵ ₉ ⁰ _{. <} ⁷ _{9 1} ^. _{7 1} ^. ₀ ² ₂ e _r e _f ^f _u b _{s ,} ^{n d} _{e o c L} ^{/ i i} i ^f _s ^F _{h g} r m u . ^{u p s} _f - l _{P 0 5} l _{l c} ^{0 0} a ^e _c ^F - ^C _{3 1 8} i _> ⁹ _. ⁴ _{7 7} ² _{7 >} ^{0 . . . n} _{f 9} R G _{< 5 0 0 n} ⁴ A o ₅ ^N _V d _i ^A e ^h _s s 1 ^t a R _n b ( O ^a _{i l} ^{d R r} _{a c L} ^/ i ^{e g y} _n ^{v F i n} _d ^p _{o h g} - ₁ ^m ₅ 0 ^{8 4} o ^{0 1} _. 0 ₇ ^. ₀ ^. ₇ ^{. i} _i ^{n o} _l B _{5 8 < 3 0 1 s} ^b ₁ ^t ₎ s _{r n} ^{w s} e ^o l r _f R O ^e _{i o} ^l _{l p p} ^{s f} ₍ ^e _c x _e ^p _a ^{R f} _n a _{) ) g} D _{o r} ^t _{( )} ^M M ⁿ _{i 9 e s} M _n ⁿ ₍ ^{d 4 h} K t _e ^ci _t ^d _l ^{n (} _{n 5} e _{( ) i p} ¹ _{: p} ⁱ _b A s _e ^h i ^{t s s} _i ^{p r y} C ^{p 1} ( _{a 1 n} r ^d a _{n e} ^{t n E} _a D D D R ^o i m ^{a I} _{c o} m _L ^a _r ⁱ _s ⁾ _{n S} ^{K K K y} O _t a ^{s o} _{i y} ^y _t t ^y _i R _r ^{t u B a} S ^y _{h e} r _p ^s _s ^{b r} _i t _i ⁿ e ⁿ i ⁿ i ⁱ _f ^h i _t f ^e _{c )} - _b ^C _: ^{x e} _{r f} ^f _f ^f _a ^{a y} _r M 4 _{1 1} R ⁴ _{e 1} l _l ^p _x ^m _{o a a 1 f} r ^{t n} _{( e} ^l O _{e b} ^{R l a} _r ^{e n} _{1 1} O _o R _{u e} R R O ^s _p O O _l m o ^p _a a _{r b} ^e _v H ^m T ^o _f ^a _T O C % ^R _h ^{R R} _t ^l _{e t} D h ^a _r C ^y _c K The relative stabilities of VNAR-hFc fusion proteins in PBS buffer were assessed. G3CP-hFc, G3CPG4- hFc and B1G4-hFc and parental B1-hFc were incubated at 2 mg / mL in sterile PBS buffer pH 7.4 containing 0.05% sodium azide at 37°C for 96h. The UV absorbance was measured at 280nm and 320nm at t=0 and t=96h. The monomericity of the proteins at t=0 and t=96 h was assessed by size- exclusion chromatography (S200 Increase 10/300GL with PBS pH 7.4 running buffer). As shown in Figure 16 the UV absorbance at both 280nm and 320nm was increased after 96h incubation for B1-hFc but not for the loop library variants (i.e. G3CP-hFc and G3CPG4-hFc). The absorbance at 320nm in particular is attributed to the scattering of light by aggregate particles. The protein concentrations for the loop library variants (i.e. G3CP-hFc and G3CPG4-hFc), calculated from the absorbance at 280 nm, remain constant throughout the experiment. The SEC analysis at t=0 versus t=96h (Figure 17) shows that loop library variants (i.e. G3CP-hFc and G3CPG4-hFc) have good stability and are more stable than the parental protein B1-hFc. Bi-paratopic VNAR Fc Fusion Proteins VNAR loop variants were genetically fused via standard [G4S]3 linkers to hIgG1 Fcs engineered for heterodimerisation (Ridgway 1996 Protein Engineering 9(7):617-21). The Knob variant has a tryptophan substitution at position 336 (T366Y) and the Hole variant has a Threonine substitution at position 407 (Y407T) (EU numbering). This approach was used to generate bi-paratopic ROR1 binders where one arm comprises a VNAR loop variant and the other arm comprises a second ROR1 binding VNAR. In addition, a cysteine substitution was incorporated in the hIgG1 Fc sequence [S239C (EU numbering)] of both Knob and Hole variants to facilitate bioconjugation with different payloads. The VNAR Fc fusion proteins were transiently co-expressed as secreted protein in CHO K1 cells and purified from the media using MabSelect™ SuRe™ (Evitria, Switzerland). Purified proteins were exchanged into PBS pH 7.4 and analysed by SEC (AdvanceBio, Agilent, running buffer DPBS), SDS PAGE and mass spectrometry to confirm sequence and protein integrity. G3CP hFc(S239C+Y407T) ASVNQTPRTATKETGESLTINCVVTGANYGLAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAYPWGAGAPYNVQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKS SDKT HTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVE VHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYT LPPSRDEL TKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQ QGNVFSC SVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 146) G3CPG4 hFc(S239C+Y407T) TRVDQSPSSLSASVGDRVTITCVLTDANYGLAATYWYRKNPGSSNKERISISGRYSESVN KGTMSFTL TISSLQPEDSATYYCRAYPWGAGAPYNVQWYDGAGTKVEIKGGGGSGGGGSGGGGSEPKS SDKTH TCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKP REEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTL PPSRDELT KNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLTSKLTVDKSRWQQ GNVFSCS VMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 147) P3A1 hFc(S239C+T366Y) TRVDQTPRTATKETGESLTINCVLTDTSYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAREARHPWLRQWYDGAGTVLTVNGGGGSGGGGSGGGGSEPKSS DKTHT CPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVH NAKTKPR EEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLP PSRDELTK NQVSLYCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQG NVFSCS VMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 148) All proteins were characterised by reducing and non-reducing SDS PAGE analysis (Figure 9) and mass spectrometry (Table 15). Binding to ROR1 was determined using Biolayer interferometry (K2 Octet instrument / Pall ForteBio) as previously described. For BLI experiments ROR1-hFc, (extracelluar domain) was immobilised on the sensors. Data is shown in Table 15. Table 15: MS characterisation of bi-paratopic VNAR-Fc fusions and binding to human ROR1 by BLI Binding of the bi-paratopic VNAR-Fc fusions to ROR1 on the surface of cancer cell lines was measured by flow cytometry using the methods described previously. Binding of VNAR-hFc fusion molecules determined by adding 100µL of PE-anti-human antibody (JIR) and incubating on ice for 30mins. KDapp values were calculated from the increase in fluorescence intensity as a function of VNAR-hFc concentration. Figure 10 shows the binding of the bi-paratopic VNAR-Fc fusions to the ROR1 ^hi A549 lung adenocarcinoma cells and the ROR1 ^low A427 cells. G3CP-P3A1 hFc (S239C+KIH) and G3CPG4- P3A1 hFc (S239C+KIH) bind strongly to A549 cells with KD app of 0.06 nM and 0.20 nM respectively but show little binding to A427 cells. EXAMPLE 6 – Loop variant VNAR drug conjugates VNAR-hFc drug conjugates Another approach for generating ADCs is to engineer cysteine substitutions or additions at positions on the light and heavy chains of antibodies and these cysteines provide reactive thiol groups for site specific labelling (Junutula 2008 Nature Biotechnology 26, 925 – 932, Jeffrey 2013, Sutherland 2016). The anti ROR1 loop library VNAR -hFc fusions were generated with an additional cysteine engineered into the Fc region as described previously, which enabled site specific labelling with maleimide derivatives of fluorescent labels (AF488) and cytotoxic drugs (MA PEG4 vc PAB EDA PNU 159682 and MA PEG4 va PAB EDA PNU 159682) (Figure 11). Generation of VNAR-hFc – drug conjugates Using a partial reduction, refolding and labelling method adapted from the literature [Junutula et al, 2008 Nat Biotech, Jeffrey et al, 2013 Bioconj Chem], these proteins were site specific labelled with the maleimide PNU derivatives. Briefly, 1mg/ml VNAR hFc solutions were prepared in PBS +100mM L- Arginine pH7.4 with 1mM EDTA. 20 molar equivalents TCEP added and incubated at 4°C for a minimum of 48 hours. 30 molar equivalents DHAA added, pH adjusted to 6.5 and incubated at room temperature for 1 hour. Refolded VNAR Fc S239C was extensively dialysed or buffer exchanged into PBS +50mM L-Arginine and quantified by UV before reacting with 4 or 5 molar equivalents maleimide PNU solution, room temperature overnight. Conjugates were purified by SEC and analysed by analytical HIC, analytical SEC, and LC-MS. Table 16 summaries the conjugates prepared. Table 16: Summary of characteristics of VNAR-PNU conjugates SDS-PAGE and mass spectrometry analysis of the final conjugates determined that the labelling had proceeded in a quantitative fashion to give highly pure homogenous protein drug conjugates with drug to antibody ratio (DAR) of 2. Binding of VNAR-hFc – drug conjugates to hROR1 by ELISA The binding of G3CP hFc and G3CPG4 hFc and their respective drug conjugates to human ROR1 was assessed by ELISA. In brief, ELISA method as follows. Wells were coated with 100ng of ROR1-his antigen and incubated, covered, at room temperature for 2hr. Plates washed 3x 400ul per well with PBST (PBS + 0.05% Tween 20 (v/v)), then blocked with 4% skimmed milk powder (w/v) in PBST for 1 hour at 37°C. Plates washed as before plus additional wash in PBS alone. B1 loop variants (VNAR- hFc fusion) binding proteins were diluted in 4% milk PBST and incubated overnight at 4 °C. Plates washed 3x with PBST, 3x PBS and binding detected using appropriate secondary detection antibody in 4% milk PBST, room temperature 1 hour. The secondary antibody used for detection was a Rabbit anti- human IgG H&L (HRP), Abcam Cat No. ab6759. Plates were washed 3x with PBST and then 100µL TMB substrate (Thermo #34029) added and the reaction allowed to proceed at r.t. for 10mins. 100 µL of 2M H2SO4 was then added to quench the reaction. The plate was centrifuged briefly before absorbance at 450nm read on a CLARIOstar plate reader (BMG Labtech). Figure 12 shows that G3CP hFc and G3CPG4 hFc PNU conjugates bind strongly to human ROR1 and there is no loss in binding activity after conjugation of the different PNU linker payloads to the parental proteins. In vitro cell viability assays for cancer cells treated with anti ROR1 VNAR drug conjugates Cells were seeded into white, clear bottom 96 well plates (Costar) and incubated at 37°C, 5% CO2 for 24 hours. On the following day, dilution series were set up for each test agent at x10 working stocks. The dose response X10 stock was: 10000, 5000, 1000, 500, 100, 50, 10, 5, 1, 0.5nM etc. 10µL of the X10 stock solutions were added to the cell plates (90µl per well) using a multichannel pipette. This resulted in a 1:10 dilution into the well and dose responses ranging from 1000nM (column 1) to 0.05nM (column 10) or continued to 0.5fM, if required, for the most sensitive cells lines. 10µl of vehicle control (PBS) was added to the control wells (columns 11 and 12). Plates were incubated at 37°C, 5% CO2 for 72-96 hours. Promega Cell Titre Glo reagent was used as per the manufacturer’s instructions to assess cell viability. Briefly, assay plates were removed from incubator and allowed to equilibrate to room temperature before adding 100µl of room temperature Cell Titre Glo reagent to each 100µl assay well. Plates were placed on a plate shaker for 2 minutes at 600rpm. Plates were allowed to sit for a further 10 minutes at room temperature prior to measuring luminescence read-out using a Clariostar plate- reader (BMG). Data was analysed by calculating the average for untreated (vehicle only) control wells and determining the % of control for each treated well. % of control data was then plotted against Log [Treatment] concentration and the IC50 value derived using non-linear regression fitting in GraphPad Prism software. The following cell lines were used PA-1 – human ovarian cancer cell line: EMEM, 10% hiFCS PA-1 ROR1 ko - human ovarian cancer cell line with ROR1 knock-out: EMEM, 10% hiFCS HEK293 – human embryonic kidney cell line: EMEM, 10% FCS HEK293 stably transfected with human ROR1 (HEK293.hROR1) – human embryonic kidney cell line stably expressing hROR1: EMEM, 10% FCS Figure 13 shows dose response curves, with corresponding IC50 values (Table 17), for cell-killing of the ROR1 positive PA-1 ovarian cancer cells and PA-1 ROR1 ko cells by G3CP-hFc-PNU conjugates (PEG4-vc PAB EDA PNU159682 and PEG4-va-EDA-PNU159682) and G3CPG4-hFc-PNU conjugate (PEG4-vc PAB EDA PNU159682). PA-1 ROR1 ko is PA-1 cancer cell-line where ROR1 expression has been knocked out. Table 17: Calculated IC50 values (nM) for the cell-killing of PA-1 and PA1 ROR1 ko cancer cells by G3CP-hFc conjugates. The ROR1 targeting VNAR-hFc conjugates show potent killing of PA-1 cell-lines, which is abrogated upon knockdown of the ROR1 receptor. There is > 100 fold window in the IC50 values for both of the G3CP-hFc PNU conjugates. Figure 18 shows dose response curves, with corresponding IC50 values (Table 18), for cell-killing of the ROR1 ^low HEK293 cells and HEK293 cells stably transfected with human ROR1 (HEK293.hROR1) by G3CP-hFc-PNU, G3CPG4-hFc-PNU and 2V-hFc-PNU conjugates (PEG4-vc PAB EDA PNU159682). 2V is a control VNAR sequence, derived from a naïve VNAR library, so is representative of this protein class but has no known target. Table 18: Calculated IC ₅₀ values (nM) for the cell-killing of HEK293 WT and HEK293.hROR1 cells by G3CP-hFc, G3CPG4-hFc and 2V-hFc conjugates. The ROR1 targeting VNAR-hFc conjugates show potent killing of the HEK293.hROR1 cell-line, which is stably transfected with the ROR1 receptor, but not the ROR1 ^low wild-type HEK293 cells. There is > 2000-fold window in the IC50 values for both the G3CP-hFc PNU and G3CPG4-hFc-PNU conjugates for killing HEK293 vs HEK293.hROR1 cells but no window for the 2V-hFc-PNU non-binding control conjugate. Example 7 - In vivo efficacy of protein-drug conjugates in patient-derived xenograft model of Triple Negative Breast Cancer (TNBC) An efficacy study in the ROR1+ HBCx-28 patient-derived TNBC xenograft model was performed by XenTech (Paris). Outbred athymic (nu/nu) female mice (HSD: Athymic Nude-Foxn1 ^nu ) were implanted subcutaneously with tumours of the same in vivo passage. Mice were monitored until the tumour implants reached the study volume recruitment criteria of 60–200 mm ³ , preferably 75–196 mm ³ in a sufficient number of animals. Mice were randomised to treatment groups such that there was no statistical difference between tumour volumes in each group. Randomisation was designated as Day 0 of the experiment. Mice were treated with vehicle or with the protein-drug conjugates B1-hFc-vc-PAB-EDA-PNU, B1G4- hFc-vc-PAB-EDA-PNU, G3CP-hFc-vc-PAB-EDA-PNU or G3CPG4-hFc-vc-PAB-EDA-PNU by single dose 0.3 mg / kg i.v. injection on day 2. All mice pre-primed with mouse IgG 20h before first PDC dose. Tumour volume was evaluated by measuring perpendicular tumour diameters, with a calliper, three times a week during the experimental period. Absolute tumour volume (ATV) was calculated using the formula TV (mm ³ ) = [length (mm) x width (mm) ² ] x 0.5, where the length and the width are the longest and the shortest perpendicular diameters of the tumour measured perpendicularly, respectively. All animals were weighed at the same time as tumour size measurement. Mice were observed and documented daily for changes in physical appearance, behaviour, adverse clinical signs and general welfare in line with local welfare and best veterinary practice guidelines. Figure 14 shows the effect of the protein-drug conjugates on tumour growth versus vehicle control. All protein drug conjugates were well tolerated and show highly statistically significant in vivo efficacy in this ROR1+ TNBC PDX model. B1G4-hFc-vc-PAB-EDA-PNU retains comparable levels of in vivo efficacy to B1-hFc-vc-PAB-EDA-PNU (data not shown). Loop library variants G3CP-hFc-vc-PAB-EDA- PNU and G3CPG4-hFc-vc-PAB-EDA-PNU show improved efficacy over the parental B1 fusion with complete and durable regressions observed for both loop library variants for the 0.3 mg / kg single dose regimen. An efficacy study was also performed in the ROR1+ HBCx-10 patient-derived TNBC xenograft model by XenTech (Paris). Outbred athymic (nu/nu) female mice (HSD: Athymic Nude-Foxn1 ^nu ) were implanted subcutaneously with tumours of the same in vivo passage. Mice were monitored until the tumour implants reached the study volume recruitment criteria of 75–196 mm ³ in a sufficient number of animals. Mice were randomised to treatment groups such that there was no statistical difference between tumour volumes in each group. Randomisation was designated as Day 0 of the experiment. Mice were treated with vehicle or with the protein-drug conjugates B1-hFc-vc-PAB-EDA-PNU, B1G4-hFc-vc-PAB-EDA-PNU, G3CP-hFc-vc-PAB-EDA-PNU or G3CPG4-hFc-vc-PAB-EDA-PNU or G3CP-hFc-va-EDA-PNU at a dose of 0.3 mg / kg i.v. injection, three times, four days apart (3 x Q4D on day 2, 6 and 10). All mice were pre-primed with mouse IgG 20h before first PDC dose. Tumour volume was evaluated by measuring perpendicular tumour diameters, with a calliper, three times a week during the experimental period. Absolute tumour volume (ATV) was calculated using the formula TV (mm ³ ) = [length (mm) x width (mm) ² ] x 0.5, where the length and the width are the longest and the shortest perpendicular diameters of the tumour measured perpendicularly, respectively. All animals were weighed at the same time as tumour size measurement. Mice were observed and documented daily for changes in physical appearance, behaviour, adverse clinical signs and general welfare in line with local welfare and best veterinary practice guidelines. Figure 19 shows the effect of the protein-drug conjugates on tumour growth versus vehicle control. All protein drug conjugates were well tolerated and show highly statistically significant in vivo efficacy in this ROR1+ TNBC PDX model with complete and durable regressions observed for this dosing regimen. EXAMPLE 8 – Bi-paratopic loop variant VNAR drug conjugates Bi-paratopic VNAR-hFc drug conjugates Bi-paratopic anti-ROR1 loop library VNAR-hFc fusions, as described in Example 5, were generated with an additional cysteine engineered into the Fc region as described previously, which enabled site specific labelling with maleimide derivatives of labels and cytotoxic drugs. Generation of Bi-paratopic VNAR-hFc – drug conjugates Bi-paratopic ROR1 binding proteins G3CP-P3A1 hFc (S239C+KIH) and G3CPG4-P3A1 hFc (S239C+KIH) were conjugated with MC-vc-PAB-MMAE or MA-PEG4-vc-PAB-EDA-PNU159682 using a partial reduction, refolding and labelling method as described in Example 6. Conjugates were purified by SEC and analysed by analytical HIC, analytical SEC, and LC-MS. Table 19 summarizes the conjugates prepared. Table 19: Summary of characteristics of Bi-paratopic VNAR-PNU conjugates Binding of the bi-paratopic VNAR-Fc-PNU conjugates to ROR1 on the surface of cancer cell lines was measured by flow cytometry using the methods described previously. Binding of VNAR-hFc-PNU molecules was determined by adding 100µL of PE-anti-human antibody (JIR) and incubating on ice for 30mins. KDapp values were calculated from the increase in fluorescence intensity as a function of VNAR- hFc concentration. Figure 20 a and b shows the binding of the bi-paratopic VNAR-Fc-PNU conjugates (PEG4-vc PAB EDA PNU159682) to the ROR1 ^hi A549 lung adenocarcinoma cells and the ROR1 ^low A427 cells along with the corresponding mono-paratopic PNU conjugates. G3CP-P3A1 hFc (S239C+KIH)-PNU and G3CPG4-P3A1 hFc (S239C+KIH)-PNU bind strongly to A549 cells with KD app of 0.92 nM and 1.83 nM respectively but show little binding to A427 cells. G3CP-P3A1 hFc (S239C+KIH)-PNU demonstrates a greater level of saturation binding to A549 cells as compared to the corresponding G3CP-hFc-PNU and P3A1-hFc-PNU conjugates (Figure 20a). Similarly, G3CPG4-P3A1 hFc (S239C+KIH)-PNU demonstrates a greater level of saturation binding to A549 cells as compared to the corresponding G3CPG4-hFc-PNU and P3A1-hFc-PNU conjugates (Figure 20b) In vitro cell viability assays for cancer cells treated with anti ROR1 Bi-paratopic VNAR drug conjugates Cell Titre Glo assays were performed as described in Example 6. Cells were incubated with VNAR-hFc conjugates at 37°C, 5% CO2 for 96 hours and the % of cell viability determined as a function of dose response. The % of control data was plotted against Log [Treatment] concentration and the IC50 value derived using non-linear regression fitting in GraphPad Prism software. The following cell lines were used PA-1 (ECACC 90113101) – human ovarian cancer cell line: EMEM, 10% hiFCS PA-1 ROR1 ko - human ovarian cancer cell line with ROR1 knock-out: EMEM, 10% hiFCS Kasumi-2 (ACC 526; DSMZ-German Collection of Microorganisms and Cell Cultures GmbH)– human B cell precursor leukaemia cell line: RPMI 1640, 10% hiFCS MHH-ES1 (ACC 167; DSMZ-German Collection of Microorganisms and Cell Cultures GmbH) – human Ewings sarcoma cell line: RPMI 1640, 10% hiFCS Figure 21 shows dose response curves for cell-killing of the ROR1 positive PA-1 ovarian cancer cells and PA-1 ROR1 ko cells by G3CP-P3A1 hFc (S239C+KIH)-PNU and G3CPG4-P3A1 hFc (S239C+KIH)-PNU conjugates (PEG4-vc PAB EDA PNU159682). PA-1 ROR1 ko is PA-1 cancer cell- line where ROR1 expression has been knocked out. Table 20 shows IC50 values, for cell-killing of Kasumi-2, MHH-ES1, PA-1 and PA-1 ROR1 ko cells by G3CP-P3A1 hFc (S239C+KIH)-PNU and G3CPG4-P3A1 hFc (S239C+KIH)-PNU conjugates (PEG4-vc PAB EDA PNU159682). The cell-surface ROR1 receptor number was determined for each cell-line by flow cytometry using BD Biosciences Quantibrite beads. Table 20: Calculated IC50 values (nM) for the cell-killing of PA-1 and PA1 ROR1 ko cancer cells by G3CP-P3A1 hFc (S239C+KIH)-PNU and G3CPG4-P3A1 hFc (S239C+KIH)-PNU conjugates. The ROR1 targeting bi-paratopic VNAR-hFc conjugates show potent killing of the ROR1+ cancer cell- lines, but not the ROR1 negative PA1.ROR1ko cell-line. EXAMPLE 9 - In vivo efficacy of bi-paratopic protein-drug conjugates in patient-derived xenograft model of Triple Negative Breast Cancer (TNBC) An efficacy study in the ROR1+ HBCx-28 patient-derived TNBC xenograft model was performed by XenTech (Paris). Outbred athymic (nu/nu) female mice (HSD: Athymic Nude-Foxn1 ^nu ) were implanted subcutaneously with tumours of the same in vivo passage. Mice were monitored until the tumour implants reached the study volume recruitment criteria of 100–200 mm ³ in a sufficient number of animals. Mice were randomised to treatment groups such that there was no statistical difference between tumour volumes in each group. Randomisation was designated as Day 0 of the experiment. Mice were treated with vehicle or with the Bi-paratopic protein-drug conjugates G3CP-P3A1 hFc (S239C+KIH)-vc-PAB-EDA- PNU and G3CPG4-P3A1 hFc (S239C+KIH) vc-PAB-EDA-PNU either by single dose 0.3 mg / kg i.v. injection on day 2 or by 3 x 0.1 mg / kg i.v. injections four days apart (3 x Q4D on day 2, 6 and 10). All mice were pre-primed with mouse IgG 20h before first PDC dose. Tumour volume was evaluated by measuring perpendicular tumour diameters, with a caliper, three times a week during the experimental period. Absolute tumour volume (ATV) was calculated using the formula TV (mm ³ ) = [length (mm) x width (mm) ² ] x 0.5, where the length and the width are the longest and the shortest perpendicular diameters of the tumour measured perpendicularly, respectively. All animals were weighed at the same time as tumour size measurement. Mice were observed and documented daily for changes in physical appearance, behaviour, adverse clinical signs and general welfare in line with local welfare and best veterinary practice guidelines. Figure 22 shows the effect of the protein-drug conjugates on tumour growth versus vehicle control. All protein drug conjugates were well tolerated and both bi-paratopic loop library variants G3CP-P3A1-hFc- vc-PAB-EDA-PNU and G3CPG4-P3A1-hFc-vc-PAB-EDA-PNU show excellent in vivo efficacy in this ROR1+ TNBC PDX model, with tumour regressions observed for both agents. EXAMPLE 10 - ROR1 VNAR Bi-specifics Bispecific target combinations for ROR1 binding VNARs include, for example, HSA for half-life extension; bispecific engagement of ROR1 and serum albumin RTKs e.g. EGFR, Her3; bispecific targeting both EGFR and ROR1 or HER3 and ROR1 on the surface of cells. The VNAR BA11, already discussed and exemplified herein, is an example of a HSA-binding VNAR. Bi- specific molecules comprising a HSA-binding VNAR (such as BA11) and another specific binding molecule are discussed. ROR1 x CD3 bispecific sequences combining N-terminal ROR1 VNARs with a C-terminal anti-CD3 scFv (clone OKT3) via 2 different length G4S linkers were expressed in CHO cells (Evitria) and purified by IMAC (HisTrap Excel, GE Healthcare) followed by SEC (Superdex 200 26/60, GE Healthcare). Similarly, biparatopic ROR1 x CD3 bispecific sequences combining N-terminal biparatopic ROR1 VNARs with the C-terminal anti-CD3 scFv were also expressed in CHO (Evitria). CD3 BiTE-like approach; examples of CD3 binding sequences for use as an ROR1 VNAR bispecific Anti CD3 scFv clone OKT3 (WO 2014028776 Zyngenia) and orientation and humanised derivatives thereof VH-[G4S]3-VL DIKLQQSGAELARPGASVKMSCKTSGYTFTRYTMHWVKQRPGQGLEWIGYINPSRGYTNY NQKFKD KATLTTDKSSSTAYMQLSSLTSEDSAVYYCARYYDDHYCLDYWGQGTTLTVSSGGGGSGG GGSGG GGSDIQLTQSPAIMSASPGEKVTMTCRASSSVSYMNWYQQKSGTSPKRWIYDTSKVASGV PYRFSG SGSGTSYSLTISSMEAEDAATYYCQQWSSNPLTFGAGTKLELKS (SEQ ID NO: 149) Humanised anti CD3 scFv UCHT1 (Arnett et al PNAS 2004101(46) 16268-16273) and derivatives thereof VL-[G ₄ S] ₃ -VH MDIQMTQTTSSLSASLGDRVTISCRASQDIRNYLNWYQQKPDGTVKLLIYYTSRLHSGVP SKFSGSGS GTDYSLTISNLEQEDIATYFCQQGNTLPWTFAGGTKLEIKGGGGSGGGGSGGGGSEVQLQ QSGPEL VKPGASMKISCKASGYSFTGYTMNWVKQSHGKNLEWMGLINPYKGVSTYNQKFKDKATLT VDKSSS TAYMELLSLTSEDSAVYYCARSGYYGDSDWYFDVWGQGTTLTVFS (SEQ ID NO: 150) EXAMPLE 11 – ROR1 CAR-T approaches Chimeric antigen receptors (CARs) based on the ROR1-specific antigen binding molecules described in the present application may be generated. Furthermore, engineered T cells expressing such a CAR may also be generated, which may then be used in, for example, adoptive cell therapy. In brief, a nucleic acid construct encoding a ROR1-specific CAR may be produced. The ROR1-specific CAR may include an intracellular activation domain, a transmembrane domain, and an extracellular domain comprising the ROR1-specific antigen binding molecule described herein. The nucleic acid construct may then be incorporated into a viral vector, such as a retroviral vector (e.g., a lentiviral vector). T cells may be isolated from a patient in need of treatment, which may then be modified to express the nucleic acid construct encoding the CAR, for example by retroviral transfection or gene-editing using approaches such as CRISPR-CAS-9. The engineered T cells may then be re-infused into the patient in order to treat the condition, such as treatment of cancer. ROR1 x PTK7 EXPERIMENTAL SUB-SECTION EXAMPLE 12 – Isolation of PTK7 specific VNAR binders VNAR libraries ELSS1 and ELSS4 were panned against biotinylated huPTK7 ECD (extracellular domains 1-7) or against biotinylated huPTK7 (domains 5-7) on pre-decorated Streptavidin Beads M-280 (Thermo Scientific Cat# 11206D) to benefit the antigen presentation. Antigens were biotinylated as per manufacturer’s instructions (Thermo Scientific Sulfo-NHS-LC-Biotin protocol Cat# A39256). Selection of 4 panning rounds was conducted and specific VNARs were identified by monoclonal phage and peri- prep binding ELISA. Library Screening 1. To rescue library phage for selections, cultures from library glycerol stocks were grown at 37 ^o C and 250 rpm, in 2xTY, 2% glucose, 100 µg/ml ampicillin to an OD600 of 0.5. 2. Cells were super-infected with 10 ⁹ M13K07 helper phage (NEB) in ratio and then incubated overnight in 2xTY, 100 µg/ml ampicillin, 50 µg/ml kanamycin at 25 ^o C and 250 rpm. 3. ^{The phage was PEG-precipitated (20% PEG/2.5 M NaCl) twice from the bacterial culture and} the resulting phage pellets were resuspended in 1 ml PBS. 4. Two hundred microliters of Dynabeads M-280 Streptavidin (Invitrogen #11205D), pre-blocked with 2% (w/v) MPBS, were coated with 200 nM biotinylated Human PTK7 ECD rotating at 20 rpm, at room temperature for 1 h. 5. ^{Library phage was de-selected by incubation with Dynabeads for 1 h rotating at room} temperature and then added to the antigen-coated beads. 6. Beads were washed 5-10 times with PBST and 5-10 times with PBS, eluted by rotating for 8 min in 400 ^l 100 mM TEA and neutralised by the addition of 200 ^l 1 M Tris-HCl pH 7.5. 7. ^{E. coli TG1 cells (10 ml) were infected with 300 μl of eluted phage for 30 min at 37 °C and grown} overnight at 37 °C on TYE agar plates containing 2 % (w/v) glucose and 100 μg/ml ampicillin. 8. Three further rounds of selection were conducted, and outputs were screened for antigen- specific binding by monoclonal phage and periplasmic extract ELISAs against human PTK7 ECD. Phage binders were detected using HRP-conjugated anti-M13 antibody (GE Healthcare, 27942101) and periplasmic protein was detected using HRP-conjugated anti-HIS antibody (Sigma A7058). Recombinant protein expression and IMAC purification 1. For expression of VNAR in E.coli set up a culture of bacterial cells transformed with plasmid encoding VNAR sequence in 10 ml of 2xTY media. Grow overnight at 37 ^C at 250 rpm. 2. Dilute overnight culture 1:50 in TB media supplemented with phosphate salts, 1% glucose and 100 µg/ml ampicillin. Incubate at 37 ^C, 250 rpm all day or as long as possible. 3. Pellet the cells by centrifugation at 4,000 x g for 15 min at 20 ^C 4. Resuspend the cells in the same volume of TB media (same supplements as above) and incubate at 30 ^C, 250 rpm overnight. 5. Pellet the cells by centrifugation at 4,000 x g for 20 min at 20 ^C 6. Resuspend the cells in the same volume of TB supplemented with phosphate salts, 100 µg/ml ampicillin (NO GLUCOSE) and IPTG of a final concentration 1 mM IPTG. Incubate at 30 ^C, 250rpm for 4-5 h. 7. Collect the cells by centrifugation at 4500 x g for 25 min and freeze the pellet. 8. Defrost the pellet next day and resuspend it in 10% culture volume ice-cold TES (fractionation buffer). Shake gently on ice for 15 min. 9. Add an equal volume ice-cold 5 mM MgSO4 (for 2.5 mM final concentration) and continue shaking gently on ice for a further 15 min. 10. Pellet the suspension by centrifugation at 9000 x g for 40 min at 4 ^C. Carefully decant the supernatant containing released periplasmic proteins into a clean falcon. 11. Add 10% of 10 fold PBS and Nickel-resin (His Pur Ni-NTA Resin, Thermo Fisher#88222) to osmotic shock solution (periplasmic extract) and incubated on roller for 1 hour. 12. Allow periplasmic extract to pass through the Poly prep chromatography column (20 ml, Bio- Rad) 13. Wash the resin with sterile PBS with total 100ml (5 x 20 ml) 14. Elute protein with 10 x 1 ml 500 mM imidazole (pH 8). 15. Dialyze eluate in PBS with agitation in dialysis cassette (Slide A Lyzer Dialysis cassette, Thermo Fisher) PTK7 specific VNARs were found in both ELSS1 and ELSS4 libraries. One unique VNAR sequence was isolated from panning of ELSS1 library on biotinylated huPTK7 (domains 5-7). Eleven and five unique VNAR sequences specific to huPTK7 (EDC) were isolated from ELLS1 and ELSS4 library respectively. All VNAR clones were expressed, purified and re-assessed for PTK7 specific binding. Fifteen clones obtained in selections on huPTK7 (ECD) recognise recombinant huPTK7 ECD in ELISA, but not recombinant huPTK7 (domains 5-7). One clone (4A12) didn’t show any specificity to huPTK7. Clone E02 derived from selection on huPTK7 (5-7) binds to both recombinant antigens, huPTK7 (ECD) and huPTK7 (5-7) (Figure 23). SEQUENCES OF ISOLATED CLONES (Sequences contain a C-terminal QASGA-His-Myc tag) P2A2-QASGA-His-Myc (SEQ ID NO: 636) ASVNQTPRTATKETGESLTINCVLTDTDPWWVRTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSF SLRIKDLTVADSATYYCKAWWHIDWFTRMWYDGAGTVLTVNQASGAHHHHHHGAEFEQKL ISEEDL P2A7-QASGA-His-Myc (SEQ ID NO: 637) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNQASGAHHHHHHGAEFEQKLI SEEDL. P2B1-QASGA-His-Myc (SEQ ID NO: 638) ASVDQTPRTATKETGESLTINCVLTDTWEEDMTTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSF SLRIKDLTVADSATYYCKAWWSPSYYSFMWYDGAGTVLTVNQASGAHHHHHHGAEFEQKL ISEEDL P2B12-QASGA-His-Myc (SEQ ID NO: 639) ASVNQTPRTATKETGESLTINCVLTDTDDQVPATSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAWWWDGNWVWVWYDGAGTVLTVNQASGAHHHHHHGAEFEQKLI SEEDL P2C6-QASGA-His-Myc (SEQ ID NO: 640) TRVDQTPRTATKETGESLTINCVLTDTDDGWPTTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSF SLRIKDLTVADSATYYCKAWWEWDLYTWYWYDGAGTVLTVNHASRAHHLHHHGAEFKHKL ISEEDL P2C7-QASGA-His-Myc (SEQ ID NO: 641) TRVDQTPRTATKETGESLTINCVLTDTEVWWPKTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSF SLRIKDLTVADSATYYCKAWWKWAEYVWYWYDGAGTVLTVNQASGAHHHHHHGAEFEQKL ISEEDL P2F8-QASGA-His-Myc (SEQ ID NO: 642) ASVNQTPRTATKETGESLTINCVLTDTTWTDELTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAWWQTSYLVWGWYDGAGTDLTVNQASGAHHHHHHGAEFEQNLI SEEDL P2G3-QASGA-His-Myc (SEQ ID NO: 643) TRVDQTPRTATKETGESLTINCVLTDTDDPVHTTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAWWEWDLFTWYWYDGAGTVLTVNQASGAHHHHHHGAEFEQKLI SEEDL P2H9-QASGA-His-Myc (SEQ ID NO: 644) ASVNQTPRTATKETGESLTINCVLTDTNHDLYTTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKAAAALNNGFLVWYDGAGTVLTVNQASGAHHHHHHGAEFEQKLI SEEDL 4A12-QASGA-His-Myc (SEQ ID NO: 645) TRVDQTPRTATKETGESLTINCVLTDTSCGLYNTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYICRATMELCQAERINGYDGAGTVLTVNQASGAHHHHHHGAEFEQKL ISEEDL 4C7-QASGA-His-Myc (SEQ ID NO: 646) ASVNQTPRTATKETGESLTINCVVTGARCGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSF SLRIKDLTVADSATYYCKA.TNCYYNHVDGAGTVLTVNQASGAHHHHHHGAEFEQKLISE EDL 4E5-QASGA-His-Myc (SEQ ID NO: 647) ASVNQTPRTATKETGESLTINCVVTGASCSWSGTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSF SLRIKDLTVADSATYYCKAVTYCISTNDMDLEYVYGAGTVLTVNQASGAHHHHHHGAEFE QKLISEED L 4H3-QASGA-His-Myc (SEQ ID NO: 648) TRVDQTPRTATKETGESLTINCVVTGASCALYRTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKARACKYDRFHVDGAGTVLTVNQASGAHHHHHHGAEFEQKLISE EDL 4D2-QASGA-His-Myc (SEQ ID NO: 649) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFS LRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNQASGAHHHHHHGAEFEQK LISEEDL E02-QASGA-His-Myc (SEQ ID NO: 650) ASVNQTPRTATKETGESLTINCVVTGAGYALAATYWYRKNPGSSNQERISISGRYVESVN KRTMSFSL RIKDLTVADSATYYCKAFLPPRVWHGVKMQHWYDGAGTVLTVNQASGAHHHHHHGAEFEQ KLISEE DL PB4-QASGA-His-Myc (SEQ ID NO: 651) ASVNQTPRTATKETGESLTINCVLTDTWEEDMTTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSF SLRIKDLTVADSATYYCKAWWSPSYYSFMWYDGAGTVLTVNQASGAHHHHHHGAEFEQKL ISEEDL PC2-QASGA-His-Myc (SEQ ID NO: 652) ASVNQTPRTATKETGESLTINCVLTDTWGPEVHTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSF SLRIKDLTVADSATYYCKAWWNADYYVFYWYDGAGTVLTVNQASGAHHHHHHGAEFEQKL ISEEDL EXAMPLE 13 Species cross- reactivity of PTK7 specific VNAR binders Three lead clones, E02, P2A7 and 4D2, were selected based on their biophysical characteristics and expression yields. Species cross-reactivity of lead clones was analysed with cynomolgus monkey and mouse PTK7 along with human antigen (both full ECD and PTK7 domains 5-7). Briefly 1. Coat 96 well plates with 1 μg/ml of huPTK7 ECD-huFc (or PTK7(ECD)-his for CCK4 and hu24 controls), huPTK7 ECD (5-7)-Fc (or PTK7(5-7)-his for CCK4 and hu24 controls), mouse PTK7 or cyno PTK7 in PBS. Incubated overnight at 4 ^o C. 2. Wash 2 x PBS and block with 200 μl/well of 4% MPBS for 1h at RT. 3. Wash 2 x PBS and add VNAR or controls at starting concentration of 1µg/ml and make 3-fold serial dilutions down the plate. Incubated for 1 h at RT. 4. Wash 3 x PBST 5. Incubate plates with 100 μl of anti-his-HRP (diluted 1:1000 in PBST) or anti huIgG-HRP for control antibodies, both diluted 1:1000 in PBST. Incubate for 1h at RT. 6. Wash 2 x PBST and 2 x PBS Add 100 μl/well of TMB substrate. Stop reaction by adding 50 μl/well of 1M H2SO4. P2A7 bound to human PTK7 (ECD), but not human PTK7 (domains 5-7), and cross-reacted with mouse and cynomolgus PTK7. 4D2 bound to human PTK7 (ECD) but not human PTK7 (domains 5-7) and cross-reacted with cynomolgus PTK7 only (did not bind mouse PTK7). E02 bound to both human PTK7 ECD and PTK7 (5-7) but did not show any species cross-reactivity with either mouse or cyno antigen (Figure 24). PTK7 binding VNARs were re-expressed using intein technology. For expression as intein fusions, DNA encoding VNARs was optimised for E. coli expression (GeneArt, Thermo) and cloned in frame into an intein expression vector. This results in a gene encoding the VNAR protein of interest fused to an engineered intein domain which in turn is fused to a chitin binding domain (CBD) to enable purification on a chitin column. Transformed E.coli cells were grown in 1L shaker flasks until OD600nm = ~0.6, cold shocked 4 °C for 2 hours then protein expression induced with 0.5mM IPTG at 18 °C overnight. Cells were lysed by sonication in lysis buffer (50mM sodium phosphate pH7.4, 0.5M NaCl, 15% glycerol, 0.5mM EDTA, 0.1% Sarkosyl, 1mM AEBSF) and centrifuged to remove cell debris. VNAR intein fusion protein was purified from clarified cell lysate by immobilising on chitin beads (NEB, S6651). Beads were washed extensively with lysis buffer followed by cleavage buffer (50mM sodium phosphate pH6.9, 200mM NaCl) and VNARs released from the beads by overnight chemical cleavage in 400mM dioxyamine, or O,O’- 1,3-propanediylbishydroxylamine, or 100mM cysteine or cysteamine to generate the corresponding C- terminal aminoxy, C-terminal cysteine or C-terminal thiol derivative of the VNARs. Cleaved VNAR supernatant was then further purified by SEC (Superdex7526/60 GE healthcare) and / or IMAC (HisTrap HP, GE Healthcare). Concentrations were determined from absorbance at 280 nm using the theoretical extinction coefficient predicted from the amino acid sequence. All proteins were characterised by reducing and non-reducing SDS PAGE analysis and mass spectrometry. The formation of the desired disulphide bond in the VNAR domain was confirmed by mass spectrometry methods. These C-terminal HisMyc or His tagged proteins were then further assessed for PTK7 binding by BLI and thermal stability by Differential Scanning Fluorimetry. Binding to human and cynomolgus PTK7 by BLI Binding kinetics were determined using the Biolayer Interferometry (BLI) Octet K2 system (ForteBio). Human or cynomolgus PTK7-hFc fusion proteins (extracelluar domains) were immobilised in sodium acetate pH5 buffer to COOH2 chips or AR2G sensors using amine coupling. VNARs were tested at various concentrations and the Ka (M ^-1 s ^-1 ), Kd (s ^-1 ) and KD (nM) values were determined using Octet Data Analysis High Throughput software (ForteBio) for Biolayer Interferometry. Binding parameters are shown in Table 21. Thermal stability assays Thermal stability assays used Applied Biosystems StepOne Real Time PCR system with the Protein Thermal Shift™ dye kit (Thermo). The assay mix was set up so that the protein was at a final concentration of 20 µM in 20 µL in PBS pH 7.4.2.5 µL 8x Thermal Shift™ Dye was added. Assays were run using the StepOne software and data analysed using Protein Thermal Shift™ software. All data are from first derivative analysis with the Tm values detailed in Table 21. Table 21: Summary of PTK7 binding properties and thermal stability of P2A7, P2B1, 4D2 and 4H3 EXAMPLE 14 – PTK7 VNAR Reformatting as Fc fusion proteins VNAR Fc Fusion Proteins Fusion of proteins to an Fc domain can improve protein solubility and stability, markedly increase plasma half-life and improve overall therapeutic effectiveness. A human IgG1 Fc sequence is shown below and further examples are shown in Figure 7. Human IgG1 Fc (hFc) EPKSSDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKF NWYVDGV EVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQ PREPQVY TLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSK LTVDKSR WQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 145) PTK7-specific VNARs were genetically fused via standard G4S linkers (typically [G4S]3) linkers to engineered hIgG1 Fc domains that contained a cysteine substitution in the hIgG1 Fc sequence, S239C (EU numbering) or a double substitution at S239C and S442C (EU numbering). The VNAR Fc fusion proteins were transiently expressed as secreted protein in CHO K1 cells and purified from the media using MabSelect™ SuRe™ (Evitria, Switzerland). Purified proteins were exchanged into PBS pH 7.4 or PBS + 100 mM Arg pH 7.4 and analysed by SEC (Superdex 75 increase 10/300 GL, running buffer PBS pH 7.4), SDS PAGE and mass spectrometry to confirm sequence and protein integrity (Table 22). Table 22: Characterisation of PTK7 VNAR-hFc fusions Binding to PTK7 was determined using Biolayer interferometry (K2 Octet instrument, Sartorius) as previously described. For BLI experiments PTK7-hFc, (extracellular domain) was immobilised on the sensors. PTK7 Binding kinetics were determined using Biolayer Interferometry (BLI) on an Octet K2 system (Sartorius). PTK7(ECD)-hFc fusion proteins (extracellular domains) were immobilised in sodium acetate pH5 buffer to COOH2 chips or AR2G sensors using amine coupling. VNAR-Fc molecules were tested at various concentrations and the Ka (M-1s-1), Kd (s-1) and KDapp (nM) values were determined using Octet Data Analysis High Throughput software (Sartorius) for Biolayer Interferometry. Alternatively, the kinetic parameters for binding were determined by immobilising the VNAR-hFc fusion onto AHC sensors. Human PTK7 (ECD) was tested at various concentrations and the Ka (M-1s-1), Kd (s-1) and KD (nM) values for 1:1 binding were determined using Octet Data Analysis High Throughput software (Sartorius) for Biolayer Interferometry. Binding parameters are shown in Table 23. Table 23: Parameters for binding of VNAR-Fc fusions to PTK7 by BLI BLI data confirms that P2A7 and 4D2 Fc fusions bind with high affinity to both human and cynomolgus PTK7. P2A7 hFc shows cross-reactivity with the mouse orthologue, whereas 4D2 hFc does not bind to mouse PTK7. In addition, BLI experiments to assess competitive binding of the VNAR-hFc fusions showed that E02, P2A7 and 4D2 do not compete with each other for PTK7 binding. Combinations of these binders can therefore be used to generate bi-paratopic PTK7 binders. Bi-paratopic VNAR Fc Fusion Proteins PTK7-specific VNARs were genetically fused via standard [G ₄ S] ₃ linkers to hIgG1 Fcs engineered for heterodimerisation (Ridgway 1996 Protein Engineering 9(7):617-21). The Knob variant has a tryptophan substitution at position 366 (T366Y) and the Hole variant has a Threonine substitution at position 407 (Y407T) (EU numbering). This approach was used to generate bi-paratopic PTK7 binders where one arm comprises a PTK7 targeting VNAR and the other arm comprises a second PTK7 binding VNAR. In addition, a cysteine substitution was incorporated in the hIgG1 Fc sequence [S239C (EU numbering) or S239C + S442C (EU numbering)] of both Knob and Hole variants to facilitate bioconjugation with different payloads. The VNAR Fc fusion proteins were transiently co-expressed as secreted protein in CHO K1 cells and purified from the media using MabSelect™ SuRe™ (Evitria, Switzerland). Purified proteins were exchanged into PBS pH 7.4 and analysed by SEC (Superdex 75 increase 10/300 GL, running buffer PBS pH 7.4), SDS PAGE and mass spectrometry to confirm sequence and protein integrity (Table 24). P2A7 hFc (S239C+T366Y) (SEQ ID NO: 509) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFSLRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSGGGGSGGG GSEPKSSDKTHTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEV KFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIE KTISKAKGQPREPQVYTLPPSRDELTKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKT TPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK 4D2 hFc (S239C+Y407T) (SEQ ID NO: 501) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFSLRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSGGGGSG GGGSEPKSSDKTHTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDP EVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAP IEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNY KTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK P2A7 hFc (S239C+S442C+T366Y) (SEQ ID NO: 515) TRVDQTPRTATKETGESLTINCVLTDTNYGLYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFSLRIKDLTVADSATYYCKAAYIERNGFLTWYDGAGTVLTVNGGGGSGGGGSGGG GSEPKSSDKTHTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEV KFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIE KTISKAKGQPREPQVYTLPPSRDELTKNQVSLYCLVKGFYPSDIAVEWESNGQPENNYKT TPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLCLSPGK 4D2 hFc (S239C+S442C+Y407T) (SEQ ID NO: 507) ASVNQTPRTATKETGESLTINCVVTGAICGWYSTSWFRKNPGTTDWERMSIGGRYVESVN KGAKSFSLRIKDLTVADSATYYCKASSWWCTDNMVPEYVYGAGTVLTVNGGGGSGGGGSG GGGSEPKSSDKTHTCPPCPAPELLGGPCVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDP EVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAP IEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNY KTTPPVLDSDGSFFLTSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLCLSPGK

D ^{s 4 0 ,} _{b 3 5 s} O ⁸ _, ^{8 s} _{, a} ⁸ ₃ ⁸ ₃ m ^{2 7} _. ⁷ _. n _{i p} ⁹ ₃ ^{5 a} _h ^x _E ⁸ _{5 ,} ⁸ C ⁸ _{, 3} ⁸ _{3 a} ² _. ^{8 D 6} _. s ^{2 ,} _{b 1 3 s} O ⁹ _, ⁹ _, s _a ⁸ ₃ ⁸ ₃ m ^{1 n} _i ⁷ _. ^{7 a} _p ¹ _. 7 h ^x _{2 3} 4 C _E ⁹ _, ^{9 8} _{, 3} ⁸ ₃ ⁴ ₂ W C M _{g s} ^{E H g} _{3 a} ^. _{8 5} ^. ₈ ⁿ _{S d o} ^{l i} % _{e s} ⁱ _y ^u _f ^{c r} _{d e} ^o _{F o} ^h - C ^{m 7 E} % _{o .} ² _. ^{g n 4} ₉ ¹ _i ^{n R} _{S A o 9 d} ^N m ^e _{t V} ^a _{r 7} ^K _L ^e _T ^/ _{n g} ^d _e ^r _e ^{0 e} _g ^{P m v} _{6 0 e i} ^c _, ^{p n} _o ⁴ ₁ ² _> ^r _{e o o} ^c _e w ^{t i} _{a s} R _s ^{r s} _{a e} ^r _i ^{n p} _{- p} ^e _{t i} ^{x e} r _{t 0} 4 ₅ o ^B _E ⁱ _{T 3} ⁶ _{4 r} ^{f p} _o ) ⁿ _{n o} ⁱ _i ^{H o} _{I c s} ^t _{a i} ^{s F} _{) c h} ^H _I ^{F K} h ₊ ^u _{f c} ^r _{e e 2} ^{K C} ₂ ^{F t} _c ^m D _{+ 2} D ⁴ _{h 4} ^a _{a r} ^a N ⁴ - ^C _{7 h} ⁷ ₉ ⁴ - ^S A ³ ₂ ⁷ ₊ ^K _T ^{C 2 S} _{A (} ^{2 C} ₉ ^P _{: P P} ³ _i ^{c 4} ₂ ^p ₂ ^S _{( o} ^t _{e a} ^{l r} _b 3 2 _a ^a _# ⁷ _{T 4} ⁹ ₄ ^p - ⁱ _{B 5} EXAMPLE 15 PTK7 VNAR-hFc drug conjugates An approach for generating ADCs is to engineer cysteine substitutions or additions at positions on the light and heavy chains of antibodies and these cysteines provide reactive thiol groups for site specific labelling (Junutula 2008 Nature Biotechnology 26, 925 – 932, Jeffrey 2013, Sutherland 2016). PTK7 VNAR-hFc proteins were generated with additional cysteines engineered into the Fc region as described previously, which enabled site-specific labelling with maleimide derivatives of labels and probes including cytotoxic payloads. Generation of PTK7 VNAR-hFc MMAE conjugates Using a partial reduction, refolding and labelling method adapted from the literature (Junutula et al, 2008 Nat Biotech, Jeffrey et al, 2013 Bioconj Chem), the PTK7 hFc (S239C±S442C) series of proteins were site specifically labelled with MC-vc-PAB-MMAE (Levena # SET0201). Briefly, for the PTK7 hFc (S239C + S442C) 1.5 mg/ml PTK7 hFc protein solutions were prepared in PBS +100mM L-Arginine pH7.4 with 1mM EDTA. 40 molar equivalents TCEP added and incubated at 4°C for a minimum of 48 hours. 50 molar equivalents DHAA added, pH adjusted to 6.5 and incubated at room temperature for 1 hour. Refolded VNAR hFc was extensively dialysed into PBS +50mM L-Arginine before reacting with 8 equivalents MC-vc-PAB-MMAE, room temperature 2 hours. The PTK7 hFc (S239C) series of proteins were site specifically labelled using a similar partial reduction, refolding approach. Briefly, 2-5 mg/ml PTK7 hFc protein solutions were prepared in PBS +100mM L- Arginine pH7.4 with 1mM EDTA. 20 molar equivalents TCEP added and incubated at 4°C for a minimum of 48 hours. 30 molar equivalents DHAA added, pH adjusted to 6.5 with 400 mM sodium phosphate pH 6.0 at 1/30th of the reaction volume and incubated at room temperature for 1 hour. Refolded PTK7 hFc was extensively dialysed into PBS +50mM L-Arginine before reacting with 4 equivalents MC-vc-PAB- MMAE, room temperature 2 hours. Conjugates were purified by SEC and analysed by SDS PAGE and LC-MS under reducing and non- reducing conditions to confirm the integrity of the conjugates. Table 25 summarizes the conjugates prepared. Generation of PTK7 VNAR-hFc PNU conjugates The same conjugation approach was used as above except in this instance the refolded VNAR Fc S239C proteins were extensively dialysed or buffer exchanged into PBS +50mM L-Arginine and quantified by UV before reacting with 4 or 5 molar equivalents maleimide PNU solution (MA PEG4 vc PAB EDA PNU 159682), room temperature overnight. Conjugates were purified by SEC and analysed by analytical HIC, analytical SEC, and LC-MS. Table 25 summarizes the conjugates prepared. d _e r _a ² ₈ ^{2 2 6} _{8 8} p _e r ₉ ⁶ p ⁵ ₉ ⁶ _{9 1} ⁵ ₁ ⁵ _{1 s} E ^{E E} U E ^E U U e _{t A A A} ^N _{A A} ^{N E E N E a} _{P P A A P A g} M M M - M M - M M - M u _{j d} M M M _{A A A} D M M D M M D M n _o ^a _o - _B - _B - _B - _B ^{- - - - c l} _y ^{E A A A} _{- B} ^E _{- B B} ^E _{- B} B ^{A A A A A c a} _{P P P F P} - _c ^{- -} _{A P} - _P ^{B -} _{A P} - _P ^{B -} _{A P} - ^h - ^v _{c c -} ^v - ^v - ^P _{- c} c R _v ^v _{c -} ^v - ^P _{- c} c ^v _{c -} ^v - ^P _{- c} c ^v - C C C - C C _v - C C _v - C A M M M ₄ M M ₄ M M ₄ M N G G G V ^E 7 _P ^{E -} _P ^E _{P A} - _A - K _A T _P M M M e _{) ) )} h t ^H _I ^H _I ^H _I f _o ^K y _{n c} ^{2 c} _F ^c _F ^c ₍ ^K ₍ ^K _{( F c c c c c c} r _a ⁱ _e ^F ₀ t _h ^{E h h h F F F F F F 7} _{h h h h h h} m _o ^r ₂ m ^{0 c} _{F A} ⁷ _A ⁷ _{A 2 2 3 2 2 2 u P E} H ² _P ² _P ² _P ^D ₄ ^D ₄ ^H ₄ D D D 4- ⁴ - ⁴ - S _: ⁷ _A ^{7 7 5} ₂ ² _{A P} ² _{A P} ² _{P e} ^l _b 2 8 6 4 1 8 6 7 0 5 0 a _{# T} ⁹ ₂ ⁹ ₂ ⁵ ₄ ³ ₅ ⁰ ₅ ⁵ ₄ ³ ₅ ⁵ ₄ ⁸ ₄ ³ ₅ ⁰ ₅ EXAMPLE 16 - Binding of PTK7 hFc-fusion proteins and drug conjugates to cell-surface PTK7 by flow cytometry Cell surface binding of P2A7, 4D2, and P2A7-4D2 hFc fusion proteins and their respective drug conjugates was assessed in different cancer cell lines NCI-H661 (ATCC, HTB-183) (PTK7 ^Hi lung large cell carcinoma)and AsPC1 (ATCC, CRL-1682) (PTK7 ^Lo pancreatic adenocarcinoma) and the resulting K _Dapp values determined. Adherent cancer cells were detached from tissue culture flasks by incubating with 0.1% EDTA/PBS solution at 37 °C for ~10 minutes or until cells detached easily. Cells were re- suspended in ice-cold PBS/2%FCS in 15ml tubes and centrifuged at 1500rpm for 5 mins at 4 °C. Supernatant was removed and the cell pellet re-suspended in PBS/2%FCS. A cell count was performed using a Z1 Coulter Particle Counter (Beckman Coulter) or Chemometec Nucleocounter NC-202 and 5 x 10^5 cells were aliquoted per test sample into a 96 well plate. Cells were incubated with 100µl of test agents at a range of concentrations, plus controls for 1hr on ice. The sample plate was centrifuged at 2000 rpm for 5mins. The supernatant was removed, and a wash performed by re-suspending the cell pellets in 0.25mL of ice-cold PBS/2%FCS using a multichannel pipette. Samples were again centrifuged at 2000rpm for 5min at 4°C. Supernatant was removed and two further washes performed as described. After the final wash and centrifugation step, excess liquid was removed by blotting the plate on tissue paper. Binding of VNAR-hFc molecules was determined by adding 100µl of of PE-anti-human antibody (JIR) and incubating on ice for 30mins. Wash steps were performed as described previously and analysis on a Cytek Biosciences Guava EasyCyte HT or Thermo Fisher Attune NxT flow cytometer. KDapp values were calculated from the increase in fluorescence intensity as a function of VNAR-hFc concentration. Bmax values are the MFI values at saturation binding. Table 26 below summarizes the binding of the PTK7-hFc proteins and drug conjugates to PTK7 ^hi human cancer cell-line NCI-H661 (KDapp and Bmax). Table 26: Summary of K _D app and Bmax values for binding of PTK7-hFc proteins and conjugates to the human cancer cell-line NCI-H661 Note Bmax values can only be compared within a series As shown in Figure 25 and Figure 26, the unconjugated monoparatopic and biparatopic VNAR-hFc proteins bind with high affinity to the PTK7 ^hi human cancer cell-line NCI-H661 but do not bind to the PTK7 ^low human cancer cell-line AsPC1. Binding to cell-surface PTK7 was saturable, with higher Bmax values observed for biparatopic binder P2A7-4D2 hFc compared to the corresponding P2A7-hFc and 4D2-hFc proteins, indicating increased cell surface binding on the surface of NCI-H661 (PTK7Hi) cells for the bi-paratopic protein. The corresponding vc-PAB-MMAE and vc-PAB-EDA-PNU drug conjugates maintain the high affinity binding to the NCI-H661 cells with no-binding observed to AsPC1 cells (PTK7 ^Lo ). Binding of the drug conjugates to cell-surface PTK7 was saturable and, as is the case for the non-conjugates, higher Bmax values were observed for the biparatopic P2A7-4D2 hFc drug conjugates as compared to the respective monoparatopic P2A7-hFc and 4D2-hFc conjugates. This indicates increased cell surface binding on the surface of NCI-H661 (PTK7Hi) cells for the bi-paratopic drug conjugates versus the monoparatopic counterparts (Figures 27 to 29). EXAMPLE 17 – In vitro cell viability assays for cancer cells treated with anti PTK7 VNAR drug conjugates Cells were seeded into white, clear bottom 96 well plates (Costar) and incubated at 37°C, 5% CO ₂ for 24 hours. On the following day, dilution series were set up for each test agent at x10 working stocks. The dose response X10 stock was: 10000, 5000, 1000, 500, 100, 50, 10, 5, 1, 0.5nM etc. 10µL of the X10 stock solutions were added to the cell plates (90µl per well) using a multichannel pipette. This resulted in a 1:10 dilution into the well and dose responses ranging from 1000nM (column 1) to 0.05nM (column 10) or continued to 0.5fM, if required, for the most sensitive cells lines. 10µl of vehicle control (PBS) was added to the control wells (columns 11 and 12). Plates were incubated at 37°C, 5% CO2 for 96 hours. Promega Cell Titre Glo reagent was used as per the manufacturer’s instructions to assess cell viability. Briefly, assay plates were removed from incubator and allowed to equilibrate to room temperature before adding 100µl of room temperature Cell Titre Glo reagent to each 100µl assay well. Plates were placed on a plate shaker for 2 minutes at 600rpm. Plates were allowed to sit for a further 10 minutes at room temperature prior to measuring luminescence read-out using a Clariostar plate- reader (BMG). Data was analysed by calculating the average for untreated (vehicle only) control wells and determining the % of control for each treated well. % of control data was then plotted against Log [Treatment] concentration and the IC50 value derived using non-linear regression fitting in GraphPad Prism software. The following cell lines were used PA-1 - human ovarian cancer cell line: EMEM, 10% hiFCS PA-1 PTK7 ko - human ovarian cancer cell line with PTK7 knock-out: EMEM, 10% hiFCS Figure 30 shows dose response curves, with corresponding IC ₅₀ values (Table 27), for cell-killing of the PTK7 positive PA-1 ovarian cancer cells and PA-1 PTK7 ko cells by P2A7-hFc-PNU conjugates (PEG4- vc PAB EDA PNU159682), 4D2-hFc-PNU conjugates (PEG4-vc PAB EDA PNU159682) and P2A7- 4D2-hFc-PNU conjugates (PEG4-vc PAB EDA PNU159682) and P2A7-4D2-hFc-MMAE conjugate (vc- PAB-MMAE). PA-1 PTK7 ko is PA-1 cancer cell-line where PTK7 expression has been knocked out. Table 27: Calculated IC50 values (nM) for the cell-killing of PA-1 and PA1 PTK7 ko cancer cells by P2A7- hFc, 4D2-hFc and P2A7 conjugates. The PTK7 targeting VNAR-hFc conjugates show potent killing of PA-1 cells, which is abrogated upon knockdown of the PTK7 receptor. Reformatting as a biparatopic binder [P2A7-4D2-hFc (S239C) vcPAB- EDA-PNU] increases the potency of the drug conjugates with respect to the equivalent mono-paratopic binders [cf P2A7-hFc (S239C) vcPAB-EDA-PNU and 4D2-hFc (S239C) vcPAB-EDA-PNU]. There is a circa 20-fold shift in IC50 for the biparatopic conjugates on PTK7 knockdown. Example 18 - In vivo efficacy of PTK7-hFc protein-drug conjugates in patient-derived xenograft model of Ovarian Cancer (OvCa) An efficacy study in the PTK7+ OVXF_OV55 patient-derived Ovarian cancer xenograft model was performed by Charles River (Freiburg). Outbred athymic (nu/nu) female mice (Crl:NMRI-Foxn1nu) were implanted subcutaneously with tumours of the same in vivo passage. Mice were monitored until the tumour implants reached the study volume recruitment criteria of 60–200 mm ³ , preferably 75–196 mm ³ in a sufficient number of animals. Mice were randomised to treatment groups such that there was no statistical difference between tumour volumes in each group. Randomisation was designated as Day 0 of the experiment. Mice were treated with vehicle or with the protein-drug conjugates P2A7-hFc-vc-PAB-EDA-PNU, 4D2-hFc-vc-PAB-EDA-PNU, P2A7-4D2-hFc-vc-PAB-EDA-PNU at a dose of 0.3 mg / kg i.v. injection, three times, four days apart (3 x Q4D on day 1, 5 and 9). Separately, P2A7-4D2-hFc-vc-PAB-EDA-PNU was also dosed at 0.1 mg / kg i.v. injection, three times, four days apart (3 x Q4D on day 1, 5 and 9). Mice were also treated with protein drug conjugate P2A7-4D2-hFc-vc-PAB-MMAE at a 2.5 mg / kg i.v. injection, four times, four days apart (4 x Q4D on day 1, 5, 9 and 13). All mice were pre-primed with mouse IgG 20h before first PDC dose. Tumour volume was evaluated by measuring perpendicular tumour diameters, with a calliper, three times a week during the experimental period. Absolute tumour volume (ATV) was calculated using the formula TV (mm ³ ) = [length (mm) x width (mm) ² ] x 0.5, where the length and the width are the longest and the shortest perpendicular diameters of the tumour measured perpendicularly, respectively. All animals were weighed at the same time as tumour size measurement. Mice were observed and documented daily for changes in physical appearance, behaviour, adverse clinical signs and general welfare in line with local welfare and best veterinary practice guidelines. Figure 31 shows the effect of the protein-drug conjugates on tumour growth versus vehicle control. All protein drug conjugates were well tolerated. P2A7-4D2-hFc-vc-PAB-EDA-PNU dosed at 0.3 mg/kg and P2A7-4D2-hFc-vc-PAB-MMAE at a 2.5 mg / kg demonstrated highly statistically significant in vivo efficacy in this PTK7+ OvCa PDX model with partial, and complete regressions observed for this dosing regimen. EXAMPLE 19 – Generation of the anti-ROR1 x anti-PTK7 bi-specific proteins ROR1 binding VNAR sequences as described previously (WO 2019/122447 and PCT/EP2021/086667, filed on 17 December 2021 were genetically fused to human IgG1 hFc sequence via standard [G4S]3 or short [G4S]1 linkers. The human IgG1 sequence comprised 1 or 2 site specific Cys substitutions (S239C ± S442C) for site specific conjugation and the T366Y knobs-into-holes (KIH) mutation for bi-specific chain pairing (EU numbering). The PTK7 binding VNARs P2A7 and 4D2 were fused to human IgG1 hFc sequence via standard [G4S]3 or short [G4S]1 linkers. The Fc region contains site-specific Cys substitutions (S239C ± S442C) for site specific conjugation and the corresponding Y407T KIH mutation for bi-specific pairing with above ROR1 VNAR chains. Bi-specific protein combinations were transiently expressed as secreted protein in CHO K1 cells and purified from the media using MabSelect™ SuRe™ (Evitria, Switzerland). Purified proteins were exchanged into PBS pH 7.4 and analysed by SEC (AdvanceBio, Agilent or Superdex200 Increase 10/300, Cytiva, running buffer PBS pH 7.4). The % high molecular weight (HMW) species was determined as the amount of protein eluting before 12.5 mL based on integration of Abs 280nm signal as a % of total protein eluting. (total Abs 280nm). SDS PAGE and mass spectrometry were also performed under reducing and native conditions to confirm sequence and protein integrity and the correct bi-specific pairing. For MS analysis proteins were deglycosylated with PNGaseF, reduced with 50mM DTT (if required) and run on Sciex X500B QTOP using MassPREP desalting column (Waters). Accordingly, different series of ROR1 x PTK7 bi-specifics were successfully generated (Tables 28-33).

⁹ _. ⁷ _. ⁷ _. ⁹ _. ⁸ _. ⁶ _. ³ _. ³ _. g _a ^. ₁ ^. ₂ ^. ₀ ^. ₀ ^. ₂ ^. ₀ ^. ₀ ^. _{0 8} 2 ₀ 8 ₃ 0 _{5 2 2 5 6} l _. m ⁶ _. 6 _. ² 1 ⁵ _. ⁵ _. ⁶ _. ⁶ _. ⁸ _{. 1 1} ⁵ ₁ ⁴ ₁ ⁴ ₁ ⁴ ₁ ⁴ ₁ L ^/ _g m ^{8 8 4 8} _{7 4 6 c 7 c 4} ^{5 0 5 8} c _{4 c 7 7 1 1 1} F _h ^F _h ^F _h ^F _{c h} ^F _{c h} ^F _{c h} ^F _{c h} ^F _{h ) ) ) ) ) ) ) )} C ₂ ^{C C C C C C 4} _{2 4} ⁴ _{2 2} ⁷ _{2 2 2 2} ^C _{2 4} ^{7 4} _{4 2} ⁴ _{A 4} ² _P ⁴ ₄ ^D ₄ ⁴ _{4 7} ⁴ ₄ ⁴ _{4 7} ^S ₊ ^S _{A +} ^{2 S} ₊ ^{D S} ₊ - ₄ ^{S -} ₄ ^{S A} ₂ ^S ₂ ^{S A} ₂ ^C _{2 P + + +} D _{+ 9} D ^{C P} ₉ - _{4 P} ^C ₉ ^{- C} ₉ ^{G C} ₉ ^{G C} ₉ ^P - ^C ₉ ⁴ - ^C _{9 -} ^{3 4} - ^{3 C 3} _{P P P} C ^{3 C 3 3 1} _A ^{3 1} _A ^{3 1} _{2 2 B} ^S ₍ ¹ _B ^S _{3 2 (} G ^S _{3 2 (} G ^S _{3 2} ^C _{2 2 2 (} G ^S _{3 (} G ^S ₍ ³ _P ^S ₍ ³ _P ^S _{( 9} 1 ₁ 2 _{9 2 0 3 8} ⁸ _{1 4 8 6} ⁹ ₆ ⁹ ₆ ⁹ ₆ ⁹ ₆ ⁹ ₆ 7 _K 7 _K ^T _{P 7 7} ^{T x K K} _{P 4 T T 4} ^x ₄ ^{G P} _x P _{P P 4} ¹ _{4 x} ^R _A ^C ₃ ^R _A ^C ₃ ^R _A ^{R 1} _A D G D G D ³ _{A B P} D a ⁹ _. ^{2 D 2} _. ^{2 3} _. ^{8 5} _. ^{8 0} _. ¹ _. ¹ _. ⁶ _{. 1 5 1 8} ⁴ ₅ ⁶ ₀ ¹ ₅ ⁶ ₄ , ₎ C _E S _{( 4 V} l ⁰ _{0 .} ⁹ ₉ 2 ₃ 6 ₅ 7 ₈ 9 ₄ 9 ₆ 2 3 r R m ⁷ _{. 1} ⁷ _{. 1} ⁵ _{. . . . . 1} ⁵ ₁ ⁴ ₁ ⁴ ₁ ⁴ ₁ ⁵ ₁ ⁵ ₂ e _k ⁿ _{o i} ^{n i l} _{s ]} ^s S _{e 4} ^{r G} _p L ^/ [ ^x _g ^{7 8 1 6} ₂ t _{r E} m _{9 7 7} ⁴ ₇ ⁵ _{6 7} ¹ ₁ ⁶ ₈ o _h ) s _{) )} ^C _{) ) 2} ^C _{2 )} C _{2 )} ^C ₂ ^{4 C} ₄ ^{4 4} _{) 4} ^C _{2 )} C 4 ^C ₂ ⁴ _{4 2} ^{S 4} ₊ ^{S 4} _{4 2} S ^{4 C} ₂ ^S _{+ 4} ^C _{+ 9} ^{4 C S} _{4 + 4} C ₉ ^{S 4} + ₄ ^{S C} ₊ ^{3 S} _{9 2 9 +} ^{S C} ₊ 3 _{+ 2} ^C ₉ ^{3 C} ₉ ^{S 3} _{2 9} ^{C C} ₂ ³ ( 2 ^S ₍ ³ _{2 9} 3 ^S ₍ ³ _{2 9} ^S ₍ ^{c S} _{F c} ^S _{( 2 4} ^S ₍ ³ ₂ ^c _{( F c} ^{h F} _{h c} ^S ₍ R _{A c} ^S ₍ ^{h F 7} h _{A 2} ^F _{h c} F ^D _: ^F _{h c} ⁷ _{A 2} ² _P ^D _{4 7 h 2} C ₇ ^F _h ^{2 Q} n ^{i A} _P ^{D -} ₄ - ₄ ^A ₂ D 2 ₂ - ₄ ^{- G G P} - ⁴ - n _{e i} ^t D o ^P _{P P P P} r - ^{4 1} - ^{C 1 1} 3 ^C ₃ ^C ₃ ^C _{3 A A} e _t o _{P B} ¹ _{B r} G G G G ³ _P ³ _P p _t r _o h _{8 s} # ¹ _{0 3 6 4 7 5 8 8} ² ₈ ⁸ ₆ ⁸ ₆ ⁸ ₆ ⁸ ₆ ⁸ ₆ ⁸ _{6 4} ⁷ R _K A ^{7 D} _K ^T _{P 7} K ⁹ ₇ ^T 2 ^K _P ^x _{4 T e} s _T ^{x G P} _x l _b ^ei _r ^P _{4 P 4 P 4 x} ^{R 1} _{4 A} ^C ₃ ^R _A ^C ₃ ^R _{A A} ^{R a} _T ^e _S ¹ _{A B} D G D G D ³ _P D a ⁷ _. ^{1 D 4} _{. 1} ⁹ _{7 0 5 9 2 7 5} 2 _{. .} ^{s 8} ₃ ⁸ ₃ ⁸ ₃ ⁸ ₃ ^{8 8 n} _i ^{1 a} ₁ ⁰ _{8 a} O _{3 3 h p} ⁹ C ^x _, ² _, ^m E ⁸ ₃ ⁸ ₃ ² ₇ ^. ₈ ^. ₇ ^. ₈ ^. ₇ ^. ₈ ^. s s ^S _{( e 4 5 4 1 5 8} r _p L ^{/ 6} _. ⁸ _. ⁹ _. ² _. ¹ _. ^{2 x} _{g 4 V} l ⁴ _{. E} m ⁰ ₆ ⁸ ₁ R m ₁ ⁴ ₁ ³ ₁ ⁴ ₁ ⁴ ₁ ⁴ ₁ 2 _r e ^{n r} _{e ]} ³ _{k o} ^{i k} _n ⁱ S ₄ S ₄ ⁿ _l ⁱ _s s L G ^G _{[ ]} 3 _e S ^r _p L ^{/ r} _{4 e} ^c _F ^c _F ^G _[ ^x _{g 6 E} m ³ _{5 1} ³ _{8 2} ⁷ _{1 1} ⁰ _{1 3} ⁷ _{4 3} ³ ₁ m _o ^h - ^h _d n ⁷ - 7 ^r _a ^C _{9 o A} ³ C 9 M 2 ² _{A P} ^{2 d} P _n ^C ₉ C _{2 3} C a _t ³ ₂ ⁹ ₃ ^{S 2 9} C c _{S 3} ^{9 1 s r} ₎ ^{S 2} _{F c} ² _{3 e} ^c _S ^{h F} _S ² _S k _] 3 ^C _{h c n} S _{9 F c} i ₄ S ⁷ 4 ³ ₂ ^{h F} _{A 2} ^F _{c L} ^G _[ G ^S ₍ ⁷ _{h A 2} ² _h ^F P ^D _h - ₄ - _{7 2} r _e c c ₂ ^{2 F} n _P ^D _{4 4 4} ^A ₂ D h ^F _h ^{R i -} _P - _P ^{G G P} - ⁴ - m _o - _P - _{A e P} ^{D t} _{P P o} ^{C C C C 1} _A ¹ _A n _o ^C ₃ ^C _{: 3} C ^r _{3 3 3 3 P} G G G G ³ _P ³ _P M 1 G G Q n _{2 3 4 5 6 7 5 6} ⁱ _e ^{0 0 0 0 9 9 t} # _{8 8 8 8} ⁰ ₈ ⁰ ₈ # _{6 6 o} ) ^r _p C _{2 2} ⁷ _K 7 _A ⁴ R 4 A ⁷ _K ^T _{P 7} 2 _P ^S ₊ ^{D x K 1 T} _{4 T 3 P} s ^{x ei} _{P 4} ^C ₉ s ^x _{P 2} ^G _{P 2} ^P _{x 2 r} ^R _c ³ _e ^{l ei} _r ^{R R 1} _A ^{R e C} _{3 A} ^F _{2 b} e ^C _{3 A} ^C _{3 A} ³ _{A S} G D _h ^S ₍ ^a _{T S} G D G D _P D 5 _{1 4 7 7 5} 0 8 _{3 3 3 3 3} ⁿ _{i 2 1 1} ^a _{h p} ² ₀ ⁹ ₃ . ₇ ^. ₈ ^. _{5 8} ^. _{5 7} ^. C ^x _E ⁹ ₃ ⁸ ₃ 9 ^{8 8 5} ₇ 5 W 2 _. ⁵ _. ⁵ _. ⁶ _. ⁷ _. ^{G [} _s 5 ₁ ⁴ ₁ ⁴ ₁ ⁴ ₁ ⁴ ₁ ^{& s} ] _e S ^r L 4 _p ^{/ x} _{g 0 2} G ^[ _E m ² ₂ ⁰ ₂ d _e ^{2 r} 7 _{6 5 0 5 i} ^x _e k _] 3 S 8 ₁ ^{0 6 4 8 m} _{) n} ⁱ S _{4 4 c 3 2 3 1} ^{G C} _L G _[ F _{9 h} C ^{r 9} _e ^c _F ^c C ³ ₂ ^h _F C ₃ ^{m 2 9} C ^S _{( o -} ^h - 9 _{3 S 3} ^{9 2} _{3 4} ^{n 7 7} o _{A A S c} ² _S ^{2 R} M 2 ² _P ² _{P c} ^{F F 7} _{h c S A h A} 2 ₂ ^F _c ^{D 1 D} _h ^F _{h :} ^r _{e ]} 3 2 _P D ₄ - _{4 4} - ₇ C 4 ^A _{2 2} ^k S D ^Q _{n 4} S P ^{n i G} ₄ - _P ^G C ^{G P} - ⁴ _{- i L [} G C ₃ ^C ₃ ⁹ _{P 3} ^{C 1} 3 _A ¹ _A ^e _t o _r ^r _e c c F _h ^F G G ² _S G ³ _P ³ _P ^{p r m -} _h - e _o k ⁿ _{P P o} ^C ₃ ^C _{3 7 8 9 0 1 n} ⁱ M 1 G G 9 ^{9 9 0 0 l} 7 _{7 7 8 8} ^d _e x ₈ # ⁰ _{9 i 8} ⁰ c ₈ m 7 _{K 2} ^F R _h T _{P 7} A ^{7 x} ₄ ^K _T ^D _A G _{P 2} ^P _x ^{3 2} 3 _P s ^{x C 1} _{2 e P 2} C 3 ^R _{A A} ^R _A ^l _b ^ei _r ^C ₃ ^{R 9} A ₃ G D ³ _P D ^a _T ^e _S G D ² _S MS analysis confirms the desired bi-specific proteins were generated in consideration of expected modifications (C-terminal Lys processing, incomplete deglycosylation and free thiol capping as appropriate) The elution volume on SEC can be a measure of the relative hydrophobicity of the different proteins, with increased elution volume, as a result of interactions with the column matrix, an indication of increasing hydrophobicity. It was noted that the ROR1 x PTK7 hFc bi-specific proteins containing the ROR1 binder B1 had increased elution volume as compared to the bi-specific proteins containing other ROR1 binders. The non B1 containing bi-specifics therefore show advantageously reduced hydrophobicity relative to B1 containing bi-specifics, thus providing improved developability. EXAMPLE 20 – ROR1 Target binding by ELISA The ROR1 x PTK7 hFc bi-specific proteins were assessed for ROR1 target binding by ELISA. Briefly, plates were coated with 2 μg/ml human ROR1 ECD His (Evitria) in PBS for 2hr at room temperature. ROR1 x PTK7 hFc bi-specifics were titrated in PBSTM (PBS + 0.05% Tween 20 (v/v) + 4% skimmed milk powder (w/v)) and plates incubated at 4°C overnight. Binding was detected using anti human IgG HRP in PBSTM (Abcam #Ab6759, 1:130,000 dilution, 1hr at room temperature] and TMB substrate (Thermo Scientific, #12617087) and absorbance measured at 450nm. As can be seen in Figure 32 all ROR1 x PTK7 bi-specific proteins bind human ROR1. EXAMPLE 21 – PTK7 Target binding by ELISA The ROR1 x PTK7 hFc bi-specific proteins were assessed for PTK7 target binding by ELISA. Briefly, plates were coated with 2 μg/ml human PTK7 ECD His (Evitria) in PBS for 2hr at room temperature. ROR1 x PTK7 hFc bi-specifics were titrated in PBSTM (PBS + 0.05% Tween 20 (v/v) + 4% skimmed milk powder (w/v)) and plates incubated at 4°C overnight. Binding was detected using anti human IgG HRP in PBSTM (Abcam #Ab6759, 1:130,000 dilution, 1hr at room temperature] and TMB substrate (Thermo Scientific, #12617087) and absorbance measured at 450nm. As can be seen in Figure 33 all ROR1 x PTK7 bi-specific proteins bind human PTK7. Example 22: Binding of ROR1 x PTK7 bi-specific hFc proteins to ROR1 and PTK7 by BLI Binding to ROR1 or PTK7 was determined using Biolayer interferometry (R4 Octet instrument, Sartorius) as previously described. For BLI experiments, PTK7 ECD His, or ROR1 ECD His was immobilised on AR2G sensors in MES-NaOH pH 5.2 using amine coupling. ROR1 x PTK7 hFc proteins were tested at various concentrations and the Ka (M ^-1 s ^-1 ), Kdis (s ^-1 ) and KDapp (nM) values were determined using Octet Data Analysis High Throughput software (Sartorius) for Biolayer Interferometry. Results are shown in Table 34 below.

C _{2 9} ^C ₊ ^{C S 3} _{2 9} ^C ₉ ^C _{2 9} ^C ₊ ^{C S 3} _{2 9} ^C ₉ ^C ₉ 3 ( 2 ^{c S} ₍ ³ _{2 9} ^{3 3} ₂ ( ³ ₉ ³ ₂ ³ _{2 2} ³ ₂ ^{c S} _{( 2} ^{3 S} _{( F c} ^h _c ^{S S} ( F ₍ ^S _{F c} 7 _{h c (} ^{c S} _{( F c} ^{h S} ₂ ^S ( ^S ( F _{( h c} ^S ₍ ^c _F ^c _F F _{h A 2} ^F _{h c} ^{h 7} _{A 2} ^F _c ^{h h} 2 ² _P ^D _{4 7} ^F _h ^F 2 ⁷ _{h A 2} ² _{h P} ^D _{4 7} ^F _h ⁷ _A ⁷ _A D ₄ - ₄ - ₄ ^A ₂ D ^{2 D -} ₄ - ₄ ^A _{2 2} D ^{2 2 -} _P ^G _P ^G _P ^P - ⁴ _{P 4 P P} 1 - ^{- - G G P 4 - - 1} _{P P P P -} 1 _{- P P} C ₃ ^C ₃ ^C _{3 A} G G G ³ _A ^C ₃ ^C ₃ ^C ₃ ^C _{3 A} ¹ _A ^C ₃ ^C _{3 P} ³ _P G G G G ³ _P ³ _P G G 1 _{-) 4} ^{s -} 0 2 _{0 3 1 4 3} ¹ _x 9 ₆ ⁹ ₆ ⁹ _{6 4 7 5 8 5 6} ⁽ 6 ⁹ ₆ ⁹ ₆ ⁸ ₆ ⁸ ₆ ⁸ ₆ ⁸ ₆ ⁸ ₆ ⁸ ₆ ⁵ ₇ ⁵ _{7 f} ^{f k} _{o ,} ) 4 _{4 4 1} - ^R s R _{A 4} ^R _A ¹ - D _{4 A 4} ^{D R R} _A ^{D R c 5 M 7} _{K A} T D ^{D 7} _{K A F} 0 D ^{h 1} _{x P 7} ⁷ _r ^T _{r 7 r} ^{7 r (} _n x ₄ ^K _{K T} ^{T e} _P x ^{e K e} _{K e} k k ^{o G P} _{P k 4 k T k} ^{T x} _i ^{n G} _i ^{n P} _i ⁿ _{P n} ^{i l ,} _{) P x} C ¹ _P ^l _{t P} ^l _{t x} ^l _t ^x M 3 _A ^r _o ^r _o ¹ _A ^r _P ^d _e ⁿ ₍ G ^{3 C} _{3 P} G ^{h C} _{3 o} ^C _{3 i S} ^x G ^h _S ³ _P ^h _S G M K ^d EXAMPLE 23 – Protein stability in PBS The protein stability for a representative panel of ROR1 x PTK7 hFc proteins was assessed. Each ROR1 x PTK7 hFc protein (1 mg) was prepared at 2 mg/ml (except for 683 and 684 at 2.9 mg/ml and 821 at 1.5 mg/ml) in PBS pH 7.4 + 0.05% sodium azide. Half the protein was used for T0 analysis and the other half was incubated at 37°C for 96h (T96). Analysis of samples by SDS PAGE (intact and reduced), MS (glycosylated, reduced) and ELISA (PTK7 and ROR1 target binding as described above) showed no significant differences between T0 and T96 for all samples. Samples at T0 and T96 were also analysed by size exclusion chromatography (S200 Increase 10/300GL with PBS pH 7.4 running buffer). SEC analysis at T0 versus T96 showed significant increase in %HMW aggregates for the B1 x 4D2 hFc variants (both standard and short linker variants) at T96h compared to T0. All other bi-specific constructs showed good stability by SEC with only small changes in the %HMW species (Δ%HMW) after incubation (little to no %HMW at T0) (Table 35 and Figures 34 and 35). Table 35 Bi-specific protein stability. Changes in percentage HMW species upon incubation in PBS pH 7.4 at 37°C The increase in %HMW for these B1 containing proteins indicates that non B1 containing bi-specifics, advantageously, have improved developability potential. EXAMPLE 24 – ROR1 x PTK7 bi-specific drug conjugates Bi-specific ROR1 x PTK7-hFc drug conjugates An approach for generating ADCs is to engineer cysteine substitutions or additions at positions on the light and heavy chains of antibodies and these cysteines provide reactive thiol groups for site specific labelling (Junutula 2008 Nature Biotechnology 26, 925 – 932, Jeffrey 2013, Sutherland 2016). ROR1 x PTK7 hFc bi-specific proteins were generated with additional cysteines engineered into the Fc region as described previously, which enabled site-specific labelling with maleimide derivatives of labels and probes including cytotoxic payloads. EXAMPLE 25 – Generation of Bi-specific ROR1 x PTK7 hFc MMAE conjugates Using a partial reduction, refolding and labelling method adapted from the literature (Junutula et al, 2008 Nat Biotech, Jeffrey et al, 2013 Bioconj Chem), the ROR1 x PTK7 hFc (S239C+S442C) series of proteins were site specifically labelled with MC-vc-PAB-MMAE (Levena # SET0201). Briefly, 2-5 mg/ml ROR1 X PTK7 hFc protein solutions were prepared in PBS +100mM L-Arginine pH7.4 with 1mM EDTA. 40 molar equivalents TCEP added and incubated at 4°C for a minimum of 48 hours. 50 molar equivalents DHAA added, pH adjusted to 6.5 with 400 mM sodium phosphate pH 6.0 at 1/30 ^th of the reaction volume and incubated at room temperature for 1 hour. Refolded ROR1 x PTK7 hFc was extensively dialysed into PBS +100mM L-Arginine before reacting with 8 equivalents MC-vc-PAB- MMAE, room temperature 2 hours. Conjugates were purified by SEC and analysed by SDS PAGE and LC-MS under reducing and non-reducing conditions to confirm the integrity of the bi-specific conjugates. Table 36 summarizes the conjugates prepared. The ROR1 x PTK7 hFc (S239C) series of proteins were site specifically labelled with MC-vc-PAB-MMAE (Levena # SET0201) using a similar partial reduction, refolding approach. Briefly, 2-5 mg/ml ROR1 X PTK7 hFc protein solutions were prepared in PBS +100mM L-Arginine pH7.4 with 1mM EDTA. 20 molar equivalents TCEP added and incubated at 4°C for a minimum of 48 hours. 30 molar equivalents DHAA added, pH adjusted to 6.5 with 400 mM sodium phosphate pH 6.0 at 1/30 ^th of the reaction volume and incubated at room temperature for 1 hour. Refolded ROR1 x PTK7 hFc was extensively dialysed into PBS +100mM L-Arginine before reacting with 4 equivalents MC-vc-PAB-MMAE, room temperature 2 hours. Conjugates were purified by SEC and analysed by SDS PAGE and LC-MS under reducing and non-reducing conditions to confirm the integrity of the bi-specific conjugates. Table 37 summarizes the conjugates prepared.

) ₄ ^E _A ^E _A ^E _A ^E _A ^E _A ^E _A ^E _A ^E _A ^E _A ^E _A R _A M M M M M M M M M M D ₍ ^M ₎ ^M ₎ ^M ₎ ^M ₎ ^M ₎ ^M ₎ ^M ₎ ^M ₎ ^M ₎ ^M _{) s} ^C ₂ ^C ₂ ^{7 C} ₂ ^C ₂ ^{C C C C 7 C C e} _t ^{4 4} _A 4 _{2 2 2 2 2 A 2 2 2} a _g ^{e 7} _{4 2 4} ² _{P 4} ^D ₄ ⁴ _{4 7} ⁴ ₄ ⁴ ₄ ^{7 4} ₄ ⁴ ₄ ² _P ⁴ ₄ ^D ₄ ⁴ ₄ u _{t A j} ^{a 2 S} ₊ ^{D S} ₊ - ₄ ^S ₊ - ₄ ^S ₊ ^A ₂ ^S _{+ 2} D ^S _{A 2 +} ^{2 S} ₊ ^{D S} ₊ - ₄ ^S ₊ - ₄ ^S ₊ n _{o g P} - ₄ ^{- G G P 4} _P - ₄ - ^{c u} _{j P} ^C ₉ 3 _P ^C ₉ 3 _P ^C ₉ 3 _P ^C _{9 -} ^{C 3 1} _{9 -} ^{C 3 1} ₉ 3 _P ^C ₉ ^{C 3} _{P 9} ^G _P ^C ₉ ^G _P ^C ₉ n ^C ₂ ^{C C C} _{A A} ^{C C 3 C 3 C 3 E} _{o 3} S _{3 2} S _{3 2} S _{3 2 2 2} S ^{3 S 3 S} _{3 2 2 2 2} S ₃ S _{3 3 A} C G ₍ G ₍ G ₍ G _{( P ( P (} G ₍ G ₍ G ^S ₍ G ^S ₍ M M ₈ 3 ₃ 4 ₄ 4 ₂ 5 ₃ 5 ₄ 5 ₂ 3 ₃ 3 ₄ 3 ₅ c _F # _{7 7 7 c 7 7 7 7 7 7} ³ ₇ h _c 7 ^F _h ^F _{h K} T _P x ₁ ^c _c ^c R _F O ^{h 7} _{F 4 K 4} ^F _h ⁷ 4 ^h _{4 K} R ^{7 T} ₇ ^{7 T} _{4 : K} ^R _{A P} x ^R _A ^{K R} _{A K} ^R _{r A} ^e _P ^R _{r A} ^{e 6 T} _P ^D ₄ ^D _T ^{D T} _P ^D _k ^x _{4 k 3 e} s ^{x G P} _x ^x _i ^{n l G D} _i ^{n l l} _b ^ei _P ^E r ^C _{A P} ^{E C} _A ^{1 E} _P ^E _{t P} ^E _{t A A} ^C _A ^r _{o A} ^r _o a _T ^e ₃ M ₃ M S G M G M ³ M ₃ M P M G M ^{h C} ₃ M S G M ^h _S 0 ^. ₀ ^. ₀ ^. ₀ ^. _{0 0 0 0 0 ) 2 ) 2 ) 2 ) 2} ^. ) ₂ ^. ) ₂ ^. ) ₂ ^. ₂ ^. ₂ C ₂ ^{C C C C C C 4} ₂ 4 ₂ 4 ₂ 4 ₂ 4 _{2 2 ) ) 4 4 4 4 4} ⁴ ₄ ⁴ ₄ ^{C C S} _{2 2 +} ^S ₊ ^S ₊ ^S ₊ ^S ₊ ^S ₊ ^S ₊ ^{4 4 C C C C} _{4 4 9 9} ^{C C C S S 3 3} ₉ 3 ₉ 3 ₉ 3 ₉ 3 ₉ 3 _{+ + 2 2 2 2 2 2 2} ^{C C S} ₍ ^S ₍ ^S ₍ ^S ₍ ^S ₍ ^S _{9 9 (} ^S ₍ ³ ₂ ^{3 c} _{2 c c c c F} ^F _{c c} ^S ₍ ^S ₍ F _h ^F _h ^F _h ^{h 7} _h ^F _{h A 2} ^F _h ^c _F ^{c h} _F h 2 ⁷ _A ² _P ^D ₇ ^{7 7} D ² ₂ - _{4 4} ^{- A} _{2 A} 2 _A 2 - _P ^D _{4 4 2} D 4 ^{E - E - E G E G E P} - ^{E 4} _{- P P} E ^{- E - 1} _{A P A P A P A P A} ¹ _{P P} ^E A ^{C C C C} _{A A} ¹ _{A A} ^C _A ^C _A 3 M ₃ M ₃ M ₃ M ₃ M M M ₃ M ₃ M G M G M G M G M ³ M P _P M ³ _P M G M G M 4 4 ₃ 3 ₆ 3 _{4 8} ³ _{7 5 8 5 6 8 8 8} ^{3 3 3 4 4} c _{8 8 8 8 8} F _h c _{F c} ^c 2 ^{h 7} _K ^F _F 7 ₂ ^T _{2 h 2} ^h ₂ R _{A K} ^R _{r P} ^R _{r 7} ^R _r ⁷ _K ^{R r D T} _{A P} ^e _k ^x _A ^{e K} _A ^e _{A e} k ^{E x D} _i ⁿ _{4 A P} ^{E l} _t ^{G D} _{k T i} ⁿ P ^{E l} _t ^P _x ^D _k E _i ^{T n l} _{P t} ^{x D} _n ⁱ P ^{E l d C} _A ^r _{o A} ^r _o ¹ _{A A} ^r _{o A e} M ₃ M ^{h C} ₃ M ^h M ^C ₃ M _i ^x M G M _S G M _S ³ _P M ^h _S G M M All of the expected DAR4 and DAR2 MMAE bi-specific conjugates were generated in good yield. Example 26: Binding of ROR1 x PTK7 bi-specific hFc MMAE conjugates to ROR1 and PTK7 by BLI Binding to ROR1 or PTK7 was determined using Biolayer interferometry (R4 Octet instrument, Sartorius) as previously described. For BLI experiments, PTK7 ECD His,or ROR1 ECD His was immobilised on AR2G sensors in MES-NaOH pH 5.2 using amine coupling. ROR1 x PTK7 hFc MMAE conjugates were tested at various concentrations and the Ka (M ^-1 s ^-1 ), Kdis (s ^-1 ) and KDapp (nM) values were determined using Octet Data Analysis High Throughput software (Sartorius) for Biolayer Interferometry (Table 38).

S _{( ) ) ( c} ^{S S} _{( ) ) (} ^{S F 7 C C} _{c (} ^c _{F c c (} ^c _F ^c _{F h A 2 2 2} ^F _{h c} ^{7 C F h F} _{h A 2 2} ^C ₂ ^F _{h c} F ^{h h} 2 ² _P ⁴ ₄ ^D ₄ ⁴ _{4 7 h} ⁷ _{A 2} ² _P ⁴ ₄ ^D ₄ ⁴ _{4 7 h} ⁷ _A ^{7 D} ₄ - ₊ - _{4 + 2 2} D ^{2 D -} _{4 +} - _{4 + 2 2} ² _{A 4} ^{S S A S S A 2 -} _P ^G _P ^C ₉ ^G _P ^C ₉ ^P - ⁴ _{- P} - ₄ D P - _P ^G _P ^C ₉ ^G _P ^C ₉ ^P - ⁴ _{- P} - _{P P} - _P C ₃ ^C ₃ ³ ₂ ^{C 3} ₂ ¹ _A ¹ _A ^{C C C 3} ₂ ^{C 3} ₂ ¹ _A ¹ _A ^{C C S} ₃ S ^{3 3} _{3 3 3} S ₃ ^{3 3} _{3 3} G G ₍ G _{( P P} G G G ₍ G ^S _{( P P} G G 1 _{-) 4} ^s 3 _{4 2 3 4 2 3 4 5 6 7 5 6} -0 4 ₇ ⁴ ₇ ⁵ ₇ ⁵ ₇ ⁵ ₇ ³ ₇ ³ ₇ ³ ₇ ³ ₇ ³ ₇ ³ ₇ ⁵ ₇ ⁵ ₇ ¹ _x ⁽ _{f 4} ^f _{o 4} ^{k R} _{, A} ^{R D} _{A 1} - ) D ¹ s E - _A ^E _A ^{M 7} M M ^c _F ⁵ 0 K T ₄ ⁷ 4 ^M _{K 4} M ^{h 1} _{x P} ^{R x} _{A 7} ⁷ 4 ^{D K R} _r ^T _{r 7 r} ⁷ _{4 T A K P} ^R _A ^{r ( K} _K ^R _{e n} o ^{G D T} _P ^e _k ^x ₄ ^{e D} _{k T} ^e _k ^T _{A P} ^{D k} _n k i ^, _{) P} ^E _A ^P _x ^{E x} _i ⁿ P ^l _t ^{G E} _i ^{n l} _t ^P _{x i} ^{n l} _t ^{x E l} M C ₃ M ¹ _{A A} M ^C ₃ ^r _{P o} ^C _{A 3} ^r M _o ¹ _A ^r _{P o} ^C _A ^d _{e 3} M _i ^{x n} ₍ G ^{M 3} _P M G ^h _S G M ^h _S ³ _P ^h _S G M M K ^d All DAR4 bi-specific MMAE conjugates show high affinity binding to both ROR1 and PTK7. For G3CPG4 containing conjugates there is a slight drop-off in ROR1 binding affinity with respect to the corresponding unconjugated proteins (described previously). EXAMPLE 27 – Killing of a panel of cancer cells in vitro by bi-specific ROR1 x PTK7-hFc MMAE conjugates In vitro cell viability assays for cancer and normal cells treated with anti ROR1xPTK7 Bi-specific VNAR drug conjugates Cell Titre Glo assays were performed as described in Example 6. Cells were incubated with bi-specific ROR1 x PTK7 hFc conjugates at 37°C, 5% CO2 for 96 hours and the % of cell viability determined as a function of dose response. The % of control data was plotted against Log [Treatment] concentration and the IC50 value derived using non-linear regression fitting in GraphPad Prism software (Table 40). The following cell lines were used ^ PA-1 (ECACC 90113101) – human ovarian cancer cell line: EMEM, 10% hiFCS ^ PA-1 ROR1 ko - human ovarian cancer cell line with ROR1 knock-out: EMEM, 10% hiFCS ^ SW403 [SW-403] (ATCC CCL-230) - human colorectal cancer cells: L-15, 10% hiFCS ^ NCI-H1703 [H1703] (ATCC CRL-5889) – human squamous lung cancer cell line: RPMI1640, 10% hiFCS ^ NCI-H1975 [H-1975, H1975] (ATCC CRL-5908) – human lung cancer cell line: RPMI1640, 10% hiFCS ^ NHEK-Ad (Lonza 00192627) – Adult normal human epidermal keratinocytes: KGM-Gold Keratinocyte growth medium Bullet kit ^ PNT2 (ECACC 95012613) – immortalized normal prostate epithelium cells: RPMI 1640, 5mM Glutamine, 10% FCS ROR1 and PTK7 cell receptor numbers were determined across the cancer cell-line panel and the normal primary NHEK-Ad cells and normal PNT2 cell-line (prostate epithelium) using a PE-conjugated ROR1 (2A2) mAb (Biolegend) and PE-conjugated anti-human PTK7 mAb clone OT12E7; (Novus Biologicals) (Table 39) Cells were incubated with PE-conjugated ROR12A2 mAb at 5µg/ml for 1 hour on ice in the dark. Quantibrite beads (BD Biosciences) were used as per the manufacturer’s instructions. Analysis was performed on Attune NxT flow cytometer (ThermoFisher). Cells were incubated with PE-conjugated anti-PTK7 OT12E7 mAb at 22µg/ml for 1 hour on ice in the dark. Quantum Simply Cellular Beads (Bangs Laboratories) were used as per the manufacturer’s instructions. Analysis was performed on Attune NxT flow cytometer (ThermoFisher). Table 39: ROR1 and PTK7 receptor numbers for a panel of cancer and normal cell lines used in the cell 5 viability assays.

² _T 9 N _P ⁷ 1 1 3 1 9 9 3 8 0 6 5 0 0 1 2 ₃ ⁸ ₂ ⁵ ₃ ⁸ ₁ ¹ ₂ ⁷ ₃ ¹ ₂ ⁵ ₂ ³ ₃ ⁹ ₂ ⁷ ₂ ⁰ ₂ ³ ₂ d A- 0 0 0 8 8 8 0 K ⁰ ₀ ^{2 0} ₀ ^{9 9 9} 2 9 0 4 ⁰ ₀ 9 5 8 6 E _{4 5 2 5 2} ⁹ ₂ ⁷ ₆ ⁰ ₄ ⁹ ₂ ⁹ ₄ ⁹ ₂ n _a ^{E E k o} _h ⁿ _{o A A A A} ^{E E} _h ^o _h p _{A A i} ^{n l} _n ^{i s l} - a M f M _t l o ^t - g _t ^r M MM M _{A A} ^s ( ^s ( o ) ) M M ^{E E} g e ^{t ni} _a ^{M r} c ^M _{o r} o _n o l _l ^{F c} _l ^E _A ^h _s ^E _A ^M _c ^{M M} F ^h _s ^c _c ^r _e ^{M c r} _e ^M _{A A} ( ^E _h s ^{E (} _c ^M M c M ⁽ _c M ^F _{h F} ^{F h} _h ^k _{n F} ^k _n ^{F c} _F ⁾ _r M ⁾ _r i _k ^g _{u h e} ^j _n - ₇ ^h _{- c A} ( _A M A ^{2 F} _h M ^c _F M ^F _h ) _r ^F _h M - ) _{7 -} - ₇ ⁱ l ^h - ⁱ l _{h r} ^{A 2} _D ^{A t} _r ² _D ^t _r - ₇ ^h - ^M _c ^{e 2 F} _k ^{Me n c} _{F k} n ^h t ^{o r} _{C 2 D} - o ^P - ⁴ _{- 7} M ^h - M- ₇ ^{e A 2} _k - ₇ ^e _{k 2} ⁴ _{- 2} ^{o 4} - ^{o A} _{2 D h} - i _l ^h - i _{l D} ^A ₂ ⁿ i ^A ₂ ^{n P} i - ^{P 4 4} _{- h} s ₍ ⁴ _h s ₍ ^P - ⁴ _{- 7} ^{2 f} ₎ ^P _C ^P _{C 2} P _{l -} ⁴ - ^P - ^P _{- l G G} ^{4 P P} _{G G} P ^{P 1} _A ¹ _A ^A _{2 D} P ⁴ - M ^{3 3 n} _{( G G} ^P _C ^P _C ^P s ^{3 3} _C ^P G ³ _{C C C C C} ^{3 3} G ³ _G ³ _{P -} ¹ G ³ _G ³ _G ³ _{G P} ¹ _{A A} 3 ^{3 e} _{G P P u} ^l _a v ⁰ # 8 5 ³ 3 7 ⁴ 2 7 ³ 3 7 ³ 5 7 ⁵ 6 4 2 4 5 3 4 6 7 7 ⁵ ₇ ⁴ ₇ ⁵ ₇ ³ ₇ ³ ₇ ⁵ ₇ ⁵ ₇ ³ ₇ ³ ₇ C _{I d c} e _{t c l} ^{a F F} _h 4 _c F ^u _{h 7 7} ^R _{A h c} ^l _a s e ^C _i ^E : _r ^K _{T A} ^{4 K} _{T 7} ^{E e P} _x M _R A ^P _x ^{D K E} _{T A} ⁴ A ^P M _R A ⁰ _S ^P M _D ⁴ _{G x} M _{D 4 e C} ^P _C M ¹ M _A l _b ^{3 a} _G ^{3 3} _{P T G} Examples of the dose response curves for cell-killing are shown in Figure 36. ROR1 x PTK7 targeting bi-specific hFc conjugates show potent killing of cancer cells expressing ROR1 or PTK7, with the most potent killing observed for PA-1, which expresses both ROR1 and PTK7 receptors (single digit nanomolar range for a number of conjugates). For the PA-1 ROR1 ko cell lines the potencies were decreased for all the conjugates with respect to the PA-1 cell-line. In general, a 2-5- fold drop-off in IC ₅₀ values was observed for these ROR1-negative, PTK7-positive cells. In addition, all conjugates showed much weaker cell-killing of SW403 colorectal cancer cells which lack both ROR1 and PTK7 expression. The bi-specific conjugates showed much poorer killing of primary adult keratinocytes (NHEK-Ad cells) and normal prostate epithelium cells (PNT2) despite high levels of PTK7 expression. Generally, the percentage of cell-killing did not reach an IC50 value over the large dose-response range used (in these instances the projected IC50 values reported are for comparative purposes only). Therefore, the ROR1 x PTK7 targeting bi-specific conjugates provide a large window for the killing of dual receptor positive cancer cells versus normal cells. The estimated IC50 values for NHEK-Ad showed that these normal cells are between 12 to 111 times less sensitive to ROR1 x PTK7-hFc MMAE conjugates than the PA- 1 cancer cells. Within a series of bi-specific conjugates, there were no major differences observed between conjugates employing a standard linker [-(G4S)3 -], a short linker -(G4S)1– or a combination of the two. EXAMPLE 28 – Beads on a string (BOS) ROR1 binding VNAR sequences (G3CP and P3A1) as described previously were genetically fused to the sequence of P2A7 binding VNAR sequences via a PGVQPCPGGGGS (SEQ ID NO: 432) (Wobbe- Cys-G ₄ S) linker which afforded the conjugation site at the middle Cys and the short spacer G ₄ S. A C- terminal sequence including a 6xHis tag (QASGAHHHHHH (SEQ ID NO: 102)) was applied to facilitate purification. The nucleotide sequences of the constructs were synthesized by Geneart (Thermo Scientific) and inserted to the pET100/D-TOPO expression vector under the control of a T7 promoter. Bi-specific protein combinations were expressed in Shuffle Xpress E. coli cells (NEB) and purified from inclusion bodies in the presence of 8 M Urea and 1 mM DTT using HisTrap Excel columns (Cytiva). The purified proteins were oxidatively refolded by stepwise dialysis of the urea down to 0.5 M in the presence of 20 mM NaPi, pH 7.8, 250 mM NaCl, 3 mM Cysteine, 1 mM Cystine. The refolded proteins were exchanged into PBS pH 7.4 and analysed by SEC (Superdex75 Increase 10/300, Cytiva, running buffer PBS pH 7.4). The % high molecular weight (HMW) species was determined as the amount of protein eluting before 12.5 mL based on integration of Abs 280nm signal as a % of total protein eluting. (total Abs 280nm). SDS PAGE and mass spectrometry were also performed under reducing and native conditions to confirm sequence and protein integrity and the correct bi-specific pairing. For MS analysis proteins were reduced with 50mM DTT (if required) and run on Sciex X500B QTOP using MassPREP desalting column (Waters). Accordingly, three ROR1 x P2A7 BOS bi-specifics were successfully generated (Table 41). Table 41: Characterisation of ROR1 x PTK7 (BOS) proteins MS analysis confirms the desired bi-specific proteins were generated in consideration of expected modifications (N-terminal Met processing, free thiol capping as appropriate) The retention volume on SEC can be an indicator of the folding status of different proteins. Assuming a protein of globular shape, the retention volume may be associated with its molecular weight. It was noted that the refolded ROR1 x P2A7 bi-specific BOS proteins all eluted at volumes higher than those expected for 26 kDa globular proteins. Example 29: Binding of ROR1 x PTK7 (BOS) proteins to ROR1 and PTK7 by BLI Binding to ROR1 or PTK7 was determined using Biolayer interferometry (R4 Octet instrument, Sartorius) as previously described. For BLI experiments, PTK7 ECD His or ROR1 ECD His was immobilised on AR2G sensors in MES-NaOH pH 5.2 using amine coupling. ROR1 x PTK7 BOS proteins were tested at various concentrations and the Ka (M ^-1 s ^-1 ), Kdis (s ^-1 ) and KDapp (nM) values were determined using Octet Data Analysis High Throughput software (Sartorius) for Biolayer Interferometry (Table 42). Table 42: Kinetic parameters for ROR1 x PTK7 BOS binding to human ROR1 and PTK7 by BLI ROR1 x PTK7 beads-on-a-string format bind with high affinity to both ROR1 and PTK7. EXAMPLE 30 – Generation of bi-specific ROR1 x PTK7 BOS MMAE conjugates The ROR1 x P2A7 bi-specific BOS proteins were prepared at 0.4-0.8 mg/ml in PBS, pH 7.4. TCEP was added at 2 mM and incubated at 22°C for 1 hour. To remove TCEP, the buffer was exchanged to PBS, 100 mM L-Arginine pH 7.4, 1 mM EDTA using a HiPrep 26/10 desalting column (Cytiva). 3 molar equivalents MC-vc-PAB-MMAE were added to the protein and incubated at 22 ^o C for 1 hour. The excess MMAE was removed using a HiPrep 26/10 desalting column equilibrated in PBS pH 7.4. The conjugates were analysed by SEC, SDS PAGE and LC-MS under reducing and non-reducing conditions to confirm the integrity of the bi-specific conjugates. Table 43 summarizes the conjugates prepared. Table 43 MMAE conjugation of the ROR1x PTK7 bi-specific BOS proteins The ROR1 x PTK7 bi-specific MMAE conjugates in a beads-on-a-string format where prepared in good yield. EXAMPLE 31 – Tumours from a wide range of different cancer indications express both ROR1 and PTK7 proteins PTK7 and ROR1 protein expression levels were investigated by Western blotting in a series of PDX models from a number of different cancer indications. Tumour fragments were weighed and 3-10X volume of RIPA buffer, containing phosphatase and protease inhibitors, was added. Tumours were homogenised at 4°C for 5min at 50Hz. Samples were sonicated for up to 30 minutes (30sec on - 30 sec off cycles) at 4°C. Lysates were centrifuged at 14000g for 15 minutes at 4 degrees and the supernatant was collected. Protein concentrations were quantified using BCA Protein Assay and samples were prepared adding loading buffer and reducing agents. Samples (~60µg/ml determined by BCA assay) were loaded on a pre-cast gel and run for approximately 1hr then transferred on PVDF or nitrocellulose membrane. Membranes were blocked in TBST with 5% milk for 1h at RT. Incubation with primary antibodies was performed overnight at 4degC in TBST + 5% milk. Commercial primary antibodies (anti ROR1 CST #16540 and anti PTK7 clone 4F9 (Merck Sigma) or anti-PTK7 clone OTI2E7 (Novus Biologicals) were used according to manufacturer’s recommendations. Beta Actin or Vinculin were used as a loading control. Membranes were washed in TBST and incubated for 1h at room temperature with secondary antibodies in TBST+ 5% milk. Both chemiluminescence and fluorescence detection methods were used to detect protein bands. PA-1 and SW403 cells were used as ROR1/PTK7 positive and negative controls respectively. PDX models from several different cancer indications were selected for analysis based on reported ROR1 mRNA expression levels. PDX models predicted to have high levels of ROR1 expression were screened for PTK7 and ROR1 protein expression by Western blot. A large number of PDX tumour samples, across different cancer indications, were shown to express both ROR1 and PTK7 proteins (Figures 37 and 38). Table 44a: ROR1 and PTK7 relative protein expression in selected PDX models from TNBC, Breast adenocarcinoma, Ovarian cancer, Sarcoma and Endometrial cancer. Protein levels were quantified by fluorescence detections methods. Table 44b: ROR1 and PTK7 relative protein expression in selected PDX models from a variety of lung cancer indications. Protein levels were quantified by chemiluminescence detections methods. Relative protein expression levels were annotated in consideration of loading controls within each experiment Table 44a and Table 44b show a selection of PDX models expressing both ROR1 and PTK7 proteins (corresponding western blots are shown in Figure 37 and 38). Examples of tumours with dual ROR1 / PTK7 expression can be found in a variety of cancer indications, including SCLC (model LXFS_650), LCLC (model LXFL_2228 and LXFL_625), lung adenocarcinoma (models LXFA_1647, LXFA_1125, LXFA_2184), Lung Squamous Cell Carcinoma (model LXFE_409), Pleuromesothelioma (model PXF- 1118), TNBC (models HBCx-28, HBCx-30, HBCx-33, HBCx-24 and HBCx-10), Breast adenocarcinoma (models MAXFHER_BR64 and MAXFTN_BR5), Ovarian cancer (models OVXF_OV55, OXVF_OV-003, OXVF_OV-006 and OVXF_899), Sarcoma (models SXFS_117, SXFS_1407 and SXFS_174) and Endometrial (Endo10561, Endo10987, Endo6489). Dual expression of ROR1 x PTK7 is advantageous for treating indications, such as lung cancer, where mono-specific ROR1 targeted therapies are not especially effective. EXAMPLE 32 – Binding of bi-specific ROR1 x PTK7-hFc MMAE conjugates to ROR1+PTK7+ cancer cells (PA1) Cell surface binding of ROR1xPTK7 VNAR-hFc MMAE conjugates (G3CP-P2A7 & G3CP-4D2), bispecific and their respective ROR1 and PTK7 monospecific MMAE drug conjugates (G3CP, P2A7 & 4D2) was assessed in different cancer cell lines PA-1 (ROR1 ^hi & PTK7 ^hi ovarian cancer cell line) and SW403 (ROR1 ^neg & PTK7 ^low colorectal cancer cell line) and the resulting KDapp values determined. Adherent cancer cells were detached from tissue culture flasks by incubating with 0.1% EDTA/PBS solution at 37 °C for ~10 minutes or until cells detached easily. Cells were re-suspended in ice-cold PBS/2%FCS in 15ml tubes and centrifuged at 1500rpm for 5 mins at 4 °C. Supernatant was removed and the cell pellet re-suspended in PBS/2%FCS. A cell count was performed using a Chemometec Nucleocounter NC-202 and 5 x 10^5 cells were aliquoted per test sample into a 96 well plate. Cells were incubated with 100µl of test agents at a range of concentrations, plus controls for 1hr on ice. The sample plate was centrifuged at 2000 rpm for 5mins. The supernatant was removed, and a wash performed by re-suspending the cell pellets in 0.25mL of ice-cold PBS/2%FCS using a multichannel pipette. Samples were again centrifuged at 2000rpm for 5min at 4°C. Supernatant was removed and two further washes performed as described. After the final wash and centrifugation step, excess liquid was removed by blotting the plate on tissue paper. Binding of VNAR-hFc MMAE conjugates was determined by adding 100µl of of PE-anti-human antibody (JIR) and incubating on ice for 30mins. Wash steps were performed as described previously and analysis on a Cytek Biosciences Guava EasyCyte HT. KDapp values were calculated from the increase in fluorescence intensity as a function of VNAR- hFc concentration. Bmax values are the MFI values at saturation binding. As shown in Figure 39 and Figure 40, the ROR1xPTK7 VNAR-hFc MMAE conjugates (G3CP-P2A7 & G3CP-4D2), bispecifics bind with high affinity to the ROR1 ^hi & PTK7 ^hi human ovarian cancer cell-line PA-1 but do not bind to the ROR1 ^neg & PTK7 ^low human colorectal cancer cell-line SW403. Binding to cell-surface ROR1 & PTK7 was saturable, with higher Bmax values observed for bispecific binder G3CP-P2A7 hFc MMAE conjugate compared to the corresponding G3CP-hFc and P2A7-hFc MMAE monospecific bivalent conjugates, indicating increased cell surface binding on the surface of PA-1 (ROR1 ^hi & PTK7hi) cells for the bispecific conjugate. Similar Bmax values are observed for bispecific binder G3CP-4D2 hFc MMAE conjugate compared to corresponding G3CP-hFc monospecific bivalent conjugate indicating similar cell surface binding levels on the surface on PA-1 (ROR1 ^hi & PTK7 ^hi ) cells for this particular bispecific conjugate and ROR1 monospecific conjugate. EXAMPLE 33 – Internalisation of bi-specific ROR1 x PTK7-hFc MMAE conjugates to ROR1+PTK7+ HEK293-ROR1 cells Internalisation of the following MMAE conjugates: ROR1 x PTK7-targeting, ROR1-hFc binders, PTK7- hFc binders and 2V-hFc non-targeting control was assessed in HEK293-ROR1 cells using an IncuCyte S3 live cell analysis instrument (Sartorius). HEK293-ROR1 stable transfectants were generated using 293 [HEK-293] (ATCC CRL-1573) provided by the American Type Culture Collection (ATCC) grown in EMEM, 10% hiFCS. Cells were seeded at a density of 3000 cells/well into a black clear-bottom 96-well plate (Corning, #3340) and left to adhere at 37 °C and 5% CO2 for 24 hrs. The test agents were mixed with FabFluor- pH Red Antibody Labeling Reagent (Sartorius, #4722) at a molar ratio of 1:2 in media, x2 final assay concentration, and incubated for 15 minutes at 37 °C to allow conjugation.50 µl of the resulting mixtures was added to appropriate wells containing cells (50 µl) to result in a final concentration of 25nM of each test agent. Images were captured periodically for 30 hours and four regions of interest were imaged from each well. Cell-by-cell analysis was performed using Incucyte integrated module. Data is presented as average red mean intensity (Red Calibrated Unit; RCU) over time. Assay was performed in triplicates. As shown in Figure 41, the ROR1xPTK7 VNAR-hFc MMAE conjugates (G3CP-P2A7 & G3CP-4D2), bispecifics have enhanced internalisation compared to ROR1 & PTK7 monospecific bivalent MMAE conjugates. Indicating that bispecific ROR1xPTK7 VNAR-hFc MMAE conjugates have enhanced internalisation compared to monospecific controls into a cell line which expresses ROR1 & PTK7. EXAMPLE 34 – Potency of bi-specific ROR1 x PTK7-hFc MMAE conjugates on ROR1+PTK7+ cancer cells (NCI-H1975) Cell Titre Glo assays were performed as described in Example 6. Cells were incubated with bi-specific ROR1 x PTK7 hFc conjugates at 37°C, 5% CO2 for 96 hours and the % of cell viability determined as a function of dose response. The % of control data was plotted against Log [Treatment] concentration and the IC ₅₀ value derived using non-linear regression fitting in GraphPad Prism software (Table 45). Table 45: Calculated IC50 values (nM) for the killing of NCI-H1975 lung adenocarcinoma cancer cells by ROR1 x PTK7 hFc MMAE conjugates and corresponding ROR1 monospecific and PTK7 monospecific control PDCs. As shown in Table 45 and Figure 42 the ROR1xPTK7 targeting VNAR-hFc conjugates show potent killing of NCI-H1975 cells. There is a circa 3-fold shift in IC50 for the ROR1xPTK7 targeting VNAR-hFc conjugates compared to ROR1 monospecific conjugate. In addition, there is a circa 2-5 fold shift in IC50 for the ROR1xPTK7 targeting VNAR-hFc conjugates compared to the respective PTK7 monospecific conjugate. EXAMPLE 35 – Generation of Bi-specific ROR1 x PTK7 hFc PNU conjugates A similar partial reduction, refolding and labelling method was used for PNU conjugation as above with some modifications. Briefly, 1-6 mg/ml VNAR hFc solutions were prepared in PBS, 100 mM L-Arg, 1 mM EDTA pH 7.4. 20 molar equivalents TCEP added and incubated at 4°C for 18 hours. 30 molar equivalents DHAA is then added, pH adjusted to 6.5 and incubated at room temperature for 3 hours. Refolded VNAR hFc was buffer exchanged into PBS, 50 mM L-Arg, pH 7.4 using NAP25 columns and concentrated to 3-4 mg/ml. Propylene glycol was then added to a 20% final concentration before addition of 4 molar equivalents maleimide PNU solution. This was incubated at room temperature for 2 hours. Conjugates were desalted using NAP-25 columns and purified using preparative size-exclusion chromatography, before being analysed by reducing and non-reducing SDS-PAGE, analytical HIC and LC-MS. Table 46 summarizes the conjugates prepared. Table 46: ROR1xPTK7 hFc PNU conjugates (DAR2) All of the expected DAR2 PNU bi-specific conjugates were generated in good yield. EXAMPLE 36 – Binding of bi-specific ROR1 x PTK7-hFc PNU conjugates to ROR1+PTK7+ cancer cells (PA1) Cell surface binding of ROR1xPTK7 VNAR-hFc PNU conjugates (G3CP-P2A7 & G3CP-4D2), bispecific and their respective ROR1 and PTK7 monospecific PNU drug conjugates (G3CP, P2A7 & 4D2) was assessed in different cancer cell lines PA-1 (ROR1 ^hi & PTK7 ^hi ovarian cancer cell line) and SW403 (ROR1 ^Neg & PTK7 ^Lo colorectal cancer cell line) and the resulting KDapp values determined as described in Example 32. As shown in Figure 43 and Figure 44, the ROR1xPTK7 VNAR-hFc PNU conjugates (G3CP-P2A7 & G3CP-4D2), bispecifics bind with high affinity to the ROR1 ^hi & PTK7 ^hi human ovarian cancer cell-line PA-1 but do not bind to the ROR1 ^neg & PTK7 ^low human colorectal cancer cell-line SW403. Binding to cell-surface ROR1 & PTK7 was saturable, with higher Bmax values observed for bispecific binder G3CP-P2A7 hFc PNU and G3CP-4D2 hFc PNU conjugate compared to the corresponding G3CP-hFc, P2A7-hFc, and 4D2-hFc PNU monospecific bivalent conjugates, indicating increased cell surface binding on the surface of PA-1 (ROR1 ^hi & PTK7 ^hi ) cells for the bispecific conjugate. EXAMPLE 37 – Killing of a panel of cancer cells in vitro by bi-specific ROR1 x PTK7-hFc PNU conjugates Cell Titre Glo assays were performed as described in Example 6. Cells were incubated with bi-specific ROR1 x PTK7 hFc conjugates at 37°C, 5% CO2 for 96 hours and the % of cell viability determined as a function of dose response. The % of control data was plotted against Log [Treatment] concentration and the IC50 value derived using non-linear regression fitting in GraphPad Prism software (Table 47). Table 47: Calculated IC50 values (nM) for the cell-killing of PA-1, NCI-H1975, NCI-H1703, SW403, NHEK-Ad and PA1 ROR1 ko cancer cells by ROR1xPTK7 targeting VNAR-hFc conjugates PNU conjugates. IC50 (nM) 96hr Examples of the dose response curves for cell-killing are shown in Figure 45. ROR1 x PTK7 targeting bi-specific hFc PNU conjugates show potent killing of cancer cells expressing ROR1 and PTK7, with the most potent killing observed for PA-1, which expresses both ROR1 and PTK7 receptors (sub nanomolar range for a number of conjugates). For the PA-1 ROR1 ko cell lines the potencies were decreased for all the conjugates with respect to the PA-1 cell-line. In general, a 10-12 fold drop-off in IC50 values was observed for these ROR1-negative, PTK7-positive cells. In addition, all conjugates showed much weaker cell-killing of SW403 colorectal cancer cells which lack both ROR1 and PTK7 expression. The bi-specific conjugates showed much poorer killing of primary adult keratinocytes (NHEK-Ad cells) despite high levels of PTK7 expression. Therefore, the ROR1 x PTK7 targeting bi-specific PNU conjugates provide a large window for the killing of dual receptor positive cancer cells versus normal cells. The estimated IC50 values for NHEK-Ad showed that these normal cells are between 23 to 223 times less sensitive to ROR1 x PTK7-hFc PNU conjugates than the PA-1 cancer cells.