FIELD OF THE INVENTION:

The present invention relates to a method to treat and diagnose peripheral t-cell lymphoma (PTCL).

BACKGROUND OF THE INVENTION:

Peripheral T-cell lymphomas (PTCL) include various entities derived from the different subsets of mature T lymphocytes (Tap, y6 and NK cells). They are a heterogeneous group of diseases that most commonly present in the lymph nodes [angioimmunoblastic T-cell lymphoma (AITL), "unspecified" peripheral T-cell lymphomas (PTCL, NOS), anaplastic large cell lymphoma (ALCL) ], in the skin [mycosis fungoides (MF), Sezary syndrome (SS) and CD30 LPD] or less frequently in other extranodal sites [hepatosplenic T-cell lymphoma (HSTL), nasal NK/T-cell lymphoma, T-cell lymphoma T type enteropathy (EATL)]. dissatisfied physician with 30% overall survival at 5 years with current chemotherapy regimens.

Among PTCL, primary cutaneous T-cell lymphoma (CTCL) constitutes a heterogeneous subgroup. Sezary syndrome (SS) is a CTCL in which the inventors are particularly interested. This is a rare CTCL but which immediately has an aggressive evolution and above all a leukemic phase allowing the purification of tumor cells for functional studies in vitro.

Immunotherapy targeting “immune checkpoints” has greatly improved the management and prognosis of many advanced cancers. These antibodies, in IgG4 format, target lymphocyte activation brakes without recruiting NK or macrophages. The most classic targets in clinical practice are the co-inhibition receptors of the TCR PD1 and CTLA4, the blocking of which reactivates the anti-tumor T lymphocytes (tumorinfiltrating lymphocytes, TILs), resulting in a reactivation of the anti-tumor immune response. The use of these immunotherapies in TL has given heterogeneous and contradictory results (1, 2) sometimes disappointing, with sometimes even acceleration of the disease (3). This can be explained by the fact that in LT, the tumor cell is itself a T lymphocyte that can express PD1. In some cases, blocking PD1 would promote the activation and therefore the proliferation and survival of tumor cells. Proof of this concept was recently provided by the study of a mouse model of LT (ITK-SYK oncogenic translocation) in which the tumor cells are PD1+. In this model, PD1 has been shown to play a haplo-insufficient tumor suppressor role, knowing that one of the PDCD1 alleles seems to be often deleted in CTCLs (4).

ICOS is a receptor normally expressed by subpopulations of T lymphocytes, in particular activated T lymphocytes, regulatory T subpopulations (Tregs) and by B lymphocytes. This receptor, similar to CD28, has the normal function of potentiating the T lymphocyte activation initiated by the CD3/TCR complex. The ICOS ligand, ICOSL, is produced in different isoforms and is normally expressed primarily by antigen-presenting cells. There is currently no therapeutic targeting the ICOS/ICOSL couple on the market in the field of PTCL, whereas different subtypes of T lymphomas express ICOS, in particular PTCL derived from TFH cells (AITL) (5) and certain aggressive CTCLs, in particular transformed MFs and SS (6). In CTCLs, a preclinical study in which the inventors participated showed that the use of specific anti-ICOS antibodies coupled with a toxin is effective in vitro and in vivo. Furthermore, the functional importance of ICOS stimulation in the oncogenesis of AITL was highlighted in a recent study based on the study of a mouse model of AITL, with in vivo demonstration of the efficacy of therapies blocking the ICOS/ICOSL interaction (7).

The identification of new specific tumor cell markers useful for diagnosis and new therapeutic targets and approaches is therefore a major challenge in PTCL and CTCL.

SUMMARY OF THE INVENTION:

In this study, the inventors showed that CTCL lines and KIR3DL2+ SC are ICOS+ and ICOSL+. Normal T lymphocytes are ICOSL-, including after CD3/CD28 stimulation, using WB/IP in cell lines (My La, HUT78 and SeAx) and SC, several isoforms of ICOSL (35, 50kDa and 60-70kDa) are observed. Using RT-PCR in cell lines, SC and monocytes from HD, they identified, alone or in combination with the "classic" isoform 2 (1112bp), the 4.1 isoform of ICOSL (2025bp for the total size of the isoform), as well as than another isoform with an intracellular part (isoform 4.2), containing an additional proline-rich domain (as compared to the 4.1 isoform), with a unique sequence in databases. More, in vitro cytotoxicity tests show significantly increased mortality of target cells compared to the control isotype (HUT78 and SeAx lines) by using a an ICOS-Fc construct.

Thus, the present invention relates to a method to treat and diagnose peripheral t-cell lymphoma (PTCL). In particular, the present invention is defined by the claims.

DETAILED DESCRIPTION OF THE INVENTION: General definitions

As use herein, the term “Peripheral T-cell lymphoma” (PTCL) has its general meaning in the art and denotes a group of T-cell lymphomas that develop away from the thymus or bone marrow. This group comprise Peripheral T-cell lymphoma not otherwise specified (PTCL- NOS), including PTCL NOS thl (PTCL-TBX21) and PTCL NOS th2 (PTCL-GATA3), angioimmunoblastic T-cel lymphoma (AITL), anaplastic large-cell lymphoma (ALCL) ALK ⁺ or ALK', adult T cell leukemia and lymphoma (ATLL), hepatosplenic T-cell lymphoma (HSTL), extranodal NK/T cell lymphomas (ENKTCL), enteropathy associated T-cell lymphoma (EATL), monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) and cutaneous T-cell lymphoma (CTCL) like mycosis fungoides and Sezary syndrome.

As used herein, the term “Cutaneous T-cell Lymphomas (CTCL))” has its general meaning in the art and denotes a class of non-Hodgkin lymphoma, which is a type of cancer of the immune system. Unlike most non-Hodgkin lymphomas (which are generally B cell related), CTCL is caused by a mutation of T cells. The tumor T cells in the body initially migrate to the skin, causing various lesions to appear. These lesions change shape as the disease progresses, typically beginning as what appears to be a rash which can be very itchy and eventually forming plaques and tumors before spreading to other parts of the body.

According to the invention, the CTCL regroup the following diseases: Mycosis Fungoides (MF) and MF variants (folliculotropic, pagetoid reticulosis, granulomatous slack skin), Sezary syndrome (SS), Primary cutaneous CD30+ lymphoproliferative diseases (cutaneous anaplastic T-cell lymphoma and lymphomatoid papulosis), Subcutaneous panniculitis-like T-cell lymphoma, Primary cutaneous gamma/delta T-cell lymphoma, primary cutaneous agressive epidermotropic cytotoxic CD8+ T-cell lymphoma, Primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder, Primary cutaneous acral CD8+T-cell lymphoma, Primary cutaneous peripheral T-cell lymphoma NOS.

As used herein, the terms "ICOS" or “ICOS receptor” for "Inducible T cell costimulator" or “inducible T cell costimulator receptor” (also known as CD278, AILIM, H4) refer to a transmembrane homodimeric glycoprotein of 55 to 60kDa which presents an IgV type domain in its extracellular part and a tyrosine within an YMFM motif in its cytoplasmic part. It has been shown that ICOS engagement with its unique ligand (ICOSL, CD275, B7-H2, B7h, B7RP- 1) induces the phosphorylation of the tyrosine in the cytoplasmic part of ICOS. Said phosphorylation is responsible for the recruitment of the p85 PI3K regulatory subunit, which activates the PI3K/AKT signaling pathway. ICOS engagement is also described to induce the expression of CD40L at the cell surface. CD40L is known to have an important effect in the cooperation between T lymphocytes and B lymphocytes. ICOS, as a member of the costimulatory B7-1/B7-2-CD28/CTLA-4 family, is rapidly induced after TCR engagement on conventional T cells (Tconv CD4+, CD8+ subsets) as well as on Treg. ICOS shows a dualistic behaviour in oncogenesis, as it can both enhance anti-tumor T cell responses and support tumor development through Tregs, as in patients suffering from melanoma or breast cancer. Its Entrez Gene ID number is 29851.

As used herein, the term “ICOS ligand” (ICOSL or CD275) denotes a glycosylated transmembrane structure, which is classified as a member of the B7 family due to the significant homology with B7 family members. The B7/CD28 superfamily provides both positive and negative co-signals to immunocytes in immune responses. ICOSL interact with ICOS, the specific receptor for ICOSL. This interaction is critically involved in the activation, proliferation, differentiation and cytokine production of T cells as well as in the antibody secretion from B cells during secondary immune responses. Several isoforms of ICOSL exist: isoform 1, isoform 2, isoform 3; isoform 4.1 and isoform 4.2.

Amino acids sequence of the isoform ICOSL 4.1 (SEQ ID NO:1):

MRLGSPGLLFLLFSSLRADTQEKEVRAMVGSDVELSCACPEGSRFDLNDVYV YWQTSESKTVVTYHIPQNSSLENVDSRYRNRALMSPAGMLRGDFSLRLFNVTPQDEQ KFHCLVLSQSLGFQEVLSVEVTLHVAANFSVPVVSAPHSPSQDELTFTCTSINGYPRPN VYWINKTDNSLLDQALQNDTVFLNMRGLYDVVSVLRIARTPSVNIGCCIENVLLQQN LTVGSQTGNDIGERDKITENPVSTGEKNAATWSILAVLCLLVVVAVAIGWVCRDRCL QHSYAGAWAVSPETELTGEFAVGSSRFWGAQGRLGCQLSFRVSKNFQKAKVPCLEQ LLFLETQRSPRWCAWHFLQPPLGMGWHPGVHFVTLRWDFPNMHRSRETSARPPRSP VPSPDQGVQGGSRHRRPAPMGCPEWVQAPAPSPRGVSRAGPGTGAQPLWGVRSGSG HRQLLSVAATPAALVCPSVPGAT

Amino acids sequence of the isoform ICOSL 4.2 (SEQ ID NO:2):

MRLGSPGLLFLLFSSLRADTQEKEVRAMVGSDVELSCACPEGSRFDLNDVYV YWQTSESKTVVTYHIPQNSSLENVDSRYRNRALMSPAGMLRGDFSLRLFNVTPQDEQ KFHCLVLSQSLGFQEVLSVEVTLHVAANFSVPVVSAPHSPSQDELTFTCTSINGYPRPN VYWINKTDNSLLDQALQNDTVFLNMRGLYDVVSVLRIARTPSVNIGCCIENVLLQQN LTVGSQTGNDIGERDKITENPVSTGEKNAATWSILAVLCLLVVVAVAIGWVCRDRCL QHSYAGAWAVSPETELTGEFAVGSSRFWGAQGRLGCQLSFRVSKNFQKAEVPCLEQ LLFLETQRSPRWCARHFLQPPLGMGWHPGVHFVTLRWDFPNMHRSRETSARLPRSP VPSPDQGVQGGSRHRRPAPMGCPEWVQAPAPSPRGVSRAGPGTGAQPPWGVQGGSR HRRPAPMGCPEWVQAPAPSPRGVCRAGPGTGAQPLWGVRSGSGHRQLLSVAATPAA LV CPSVPGAT

As used herein, the term “patient” or ‘subject” denotes a mammal, such as a rodent, a feline, a canine, and a primate. Particularly, the subject according to the invention is a human. More particularly, the subject according to the invention suffers from a PTCL.

As used herein and according to all aspects of the invention, the term “sample” denotes, blood, peripheral-blood, serum, plasma, blood mononuclear cells (PBMCs) or cancer biopsy and particularly PTCL biopsy. In particular embodiment, the sample is previously obtained from a subject.

Diagnostic method

A first aspect of the invention relates to a method of diagnosing a Peripheral T-cell lymphoma (PTCL) in a patient in need thereof comprising i) determining in a sample obtained from the patient the expression level of inducible T cell costimulatory ligand (ICOSL) ii) comparing the expression level determined at step i) with its predetermined reference value and iii) concluding that the patient in need thereof has a PTCL when the expression level determined at step i) is higher than its predetermined reference value.

In a particular embodiment, ICOSL is ICOSL 4.

Thus, in other words, the invention relates to a method of diagnosing a Peripheral T-cell lymphoma (PTCL) in a patient in need thereof comprising i) determining in a sample obtained from the patient the expression level of ICOSL 4 ii) comparing the expression level determined at step i) with its predetermined reference value and iii) concluding that the patient in need thereof has a PTCL when the expression level determined at step i) is higher than its predetermined reference value.

In a particular embodiment, ICOSL 4 is ICOSL 4.1 or ICOSL 4.2.

Measuring the expression level of ICOSL (i.e ICOSL 4 such as ICOSL 4.1 or ICOSL 4.2) can be done by measuring the gene expression level of ICOSL, such as ICOSL 4, or by measuring the level of the protein ICOSL, such as ICOSL 4, and can be performed by a variety of techniques well known in the art.

Typically, the expression level of a gene may be determined by determining the quantity of mRNA. Methods for determining the quantity of mRNA are well known in the art. For example the nucleic acid contained in the samples (e.g., cell or tissue prepared from the patient) is first extracted according to standard methods, for example using lytic enzymes or chemical solutions or extracted by nucleic-acid-binding resins following the manufacturer's instructions. The extracted mRNA is then detected by hybridization (e. g., Northern blot analysis, in situ hybridization) and/or amplification (e.g., RT-PCR).

Other methods of Amplification include ligase chain reaction (LCR), transcription- mediated amplification (TMA), strand displacement amplification (SDA) and nucleic acid sequence-based amplification (NASBA).

Nucleic acids having at least 10 nucleotides and exhibiting sequence complementarity or homology to the mRNA of interest herein find utility as hybridization probes or amplification primers. It is understood that such nucleic acids need not be identical but are typically at least about 80% identical to the homologous region of comparable size, more preferably 85% identical and even more preferably 90-95% identical. In certain embodiments, it will be advantageous to use nucleic acids in combination with appropriate means, such as a detectable label, for detecting hybridization.

Typically, the nucleic acid probes include one or more labels, for example to permit detection of a target nucleic acid molecule using the disclosed probes. In various applications, such as in situ hybridization procedures, a nucleic acid probe includes a label (e.g., a detectable label). A “detectable label” is a molecule or material that can be used to produce a detectable signal that indicates the presence or concentration of the probe (particularly the bound or hybridized probe) in a sample. Thus, a labeled nucleic acid molecule provides an indicator of the presence or concentration of a target nucleic acid sequence (e.g., genomic target nucleic acid sequence) (to which the labeled uniquely specific nucleic acid molecule is bound or hybridized) in a sample. A label associated with one or more nucleic acid molecules (such as a probe generated by the disclosed methods) can be detected either directly or indirectly. A label can be detected by any known or yet to be discovered mechanism including absorption, emission and/ or scattering of a photon (including radio frequency, microwave frequency, infrared frequency, visible frequency and ultra-violet frequency photons). Detectable labels include colored, fluorescent, phosphorescent and luminescent molecules and materials, catalysts (such as enzymes) that convert one substance into another substance to provide a detectable difference (such as by converting a colorless substance into a colored substance or vice versa, or by producing a precipitate or increasing sample turbidity), haptens that can be detected by antibody binding interactions, and paramagnetic and magnetic molecules or materials.

Particular examples of detectable labels include fluorescent molecules (or fluorochromes). Numerous fluorochromes are known to those of skill in the art, and can be selected, for example from Life Technologies (formerly Invitrogen), e.g., see, The Handbook — A Guide to Fluorescent Probes and Labeling Technologies). Examples of particular fluorophores that can be attached (for example, chemically conjugated) to a nucleic acid molecule (such as a uniquely specific binding region) are provided in U.S. Pat. No. 5,866, 366 to Nazarenko et al., such as 4-acetamido-4'-isothiocyanatostilbene-2,2' disulfonic acid, acridine and derivatives such as acridine and acridine isothiocyanate, 5-(2'-aminoethyl) aminonaphthalene- 1 -sulfonic acid (EDANS), 4-amino -N- [3 vinylsulfonyl)phenyl]naphthalimide-3,5 disulfonate (Lucifer Yellow VS), N-(4-anilino-l- naphthyljmaleimide, antllranilamide, Brilliant Yellow, coumarin and derivatives such as coumarin, 7-amino-4-methylcoumarin (AMC, Coumarin 120), 7-amino-4- trifluoromethylcouluarin (Coumarin 151); cyanosine; 4',6-diaminidino-2-phenylindole (DAPI); 5',5"dibromopyrogallol-sulfonephthalein (Bromopyrogallol Red); 7 -diethylamino -3 (4'-isothiocyanatophenyl)-4-methylcoumarin; diethylenetriamine pentaacetate; 4,4'- diisothiocyanatodihydro-stilbene-2,2'-disulfonic acid; 4,4'-diisothiocyanatostilbene-2,2'- disulforlic acid; 5-[dimethylamino] naphthalene- 1 -sulfonyl chloride (DNS, dansyl chloride); 4-(4'-dimethylaminophenylazo)benzoic acid (DABCYL); 4-dimethylaminophenylazophenyl- 4'-isothiocyanate (DABITC); eosin and derivatives such as eosin and eosin isothiocyanate; erythrosin and derivatives such as erythrosin B and erythrosin isothiocyanate; ethidium; fluorescein and derivatives such as 5-carboxyfluorescein (FAM), 5-(4,6diclllorotriazin-2- yDaminofluorescein (DTAF), 2'7'dimethoxy-4'5'-dichloro-6-carboxyfluorescein (JOE), fluorescein, fluorescein isothiocyanate (FITC), and QFITC Q(RITC); 2',7'-difluorofluorescein (OREGON GREEN®); fluorescamine; IR144; IR1446; Malachite Green isothiocyanate; 4- methylumbelliferone; ortho cresolphthalein; nitrotyrosine; pararosaniline; Phenol Red; B- phycoerythrin; o-phthaldialdehyde; pyrene and derivatives such as pyrene, pyrene butyrate and succinimidyl 1 -pyrene butyrate; Reactive Red 4 (Cibacron Brilliant Red 3B-A); rhodamine and derivatives such as 6-carboxy-X-rhodamine (ROX), 6-carboxyrhodamine (R6G), lissamine rhodamine B sulfonyl chloride, rhodamine (Rhod), rhodamine B, rhodamine 123, rhodamine X isothiocyanate, rhodamine green, sulforhodamine B, sulforhodamine 101 and sulfonyl chloride derivative of sulforhodamine 101 (Texas Red); N,N,N',N'-tetramethyl-6-carboxyrhodamine (TAMRA); tetramethyl rhodamine; tetramethyl rhodamine isothiocyanate (TRITC); riboflavin; rosolic acid and terbium chelate derivatives. Other suitable fluorophores include thiol-reactive europium chelates which emit at approximately 617 nm (Heyduk and Heyduk, Analyt. Biochem. 248:216-27, 1997; J. Biol. Chem. 274:3315-22, 1999), as well as GFP, LissamineTM, diethylaminocoumarin, fluorescein chlorotriazinyl, naphthofluorescein, 4,7-dichlororhodamine and xanthene (as described in U.S. Pat. No. 5,800,996 to Lee et al.) and derivatives thereof. Other fluorophores known to those skilled in the art can also be used, for example those available from Life Technologies (Invitrogen; Molecular Probes (Eugene, Oreg.)) and including the ALEXA FLUOR® series of dyes (for example, as described in U.S. Pat. Nos. 5,696,157, 6, 130, 101 and 6,716,979), the BODIPY series of dyes (dipyrrometheneboron difluoride dyes, for example as described in U.S. Pat. Nos. 4,774,339, 5,187,288, 5,248,782, 5,274,113, 5,338,854, 5,451,663 and 5,433,896), Cascade Blue (an amine reactive derivative of the sulfonated pyrene described in U.S. Pat. No. 5,132,432) and Marina Blue (U.S. Pat. No. 5,830,912).

In addition to the fluorochromes described above, a fluorescent label can be a fluorescent nanoparticle, such as a semiconductor nanocrystal, e.g., a QUANTUM DOTTM (obtained, for example, from Life Technologies (QuantumDot Corp, Invitrogen Nanocrystal Technologies, Eugene, Oreg.); see also, U.S. Pat. Nos. 6,815,064; 6,682,596; and 6,649, 138). Semiconductor nanocrystals are microscopic particles having size-dependent optical and/or electrical properties. When semiconductor nanocrystals are illuminated with a primary energy source, a secondary emission of energy occurs of a frequency that corresponds to the handgap of the semiconductor material used in the semiconductor nanocrystal. This emission can he detected as colored light of a specific wavelength or fluorescence. Semiconductor nanocrystals with different spectral characteristics are described in e.g., U.S. Pat. No. 6,602,671. Semiconductor nanocrystals that can he coupled to a variety of biological molecules (including dNTPs and/or nucleic acids) or substrates by techniques described in, for example, Bruchez et al., Science 281 :20132016, 1998; Chan et al., Science 281:2016-2018, 1998; and U.S. Pat. No. 6,274,323. Formation of semiconductor nanocrystals of various compositions are disclosed in, e.g., U.S. Pat. Nos. 6,927, 069; 6,914,256; 6,855,202; 6,709,929; 6,689,338; 6,500,622; 6,306,736; 6,225,198; 6,207,392; 6,114,038; 6,048,616; 5,990,479; 5,690,807; 5,571,018; 5,505,928; 5,262,357 and in U.S. Patent Publication No. 2003/0165951 as well as PCT Publication No. 99/26299 (published May 27, 1999). Separate populations of semiconductor nanocrystals can he produced that are identifiable based on their different spectral characteristics. For example, semiconductor nanocrystals can he produced that emit light of different colors based on their composition, size or size and composition. For example, quantum dots that emit light at different wavelengths based on size (565 nm, 655 nm, 705 nm, or 800 nm emission wavelengths), which are suitable as fluorescent labels in the probes disclosed herein are available from Life Technologies (Carlshad, Calif).

Additional labels include, for example, radioisotopes (such as 3 H), metal chelates such as DOTA and DPTA chelates of radioactive or paramagnetic metal ions like Gd3+, and liposomes.

Detectable labels that can he used with nucleic acid molecules also include enzymes, for example horseradish peroxidase, alkaline phosphatase, acid phosphatase, glucose oxidase, beta-galactosidase, beta-glucuronidase, or beta-lactamase.

Alternatively, an enzyme can he used in a metallographic detection scheme. For example, silver in situ hybridization (SISH) procedures involve metallographic detection schemes for identification and localization of a hybridized genomic target nucleic acid sequence. Metallographic detection methods include using an enzyme, such as alkaline phosphatase, in combination with a water-soluble metal ion and a redox-inactive substrate of the enzyme. The substrate is converted to a redox-active agent by the enzyme, and the redoxactive agent reduces the metal ion, causing it to form a detectable precipitate. (See, for example, U.S. Patent Application Publication No. 2005/0100976, PCT Publication No. 2005/ 003777 and U.S. Patent Application Publication No. 2004/ 0265922). Metallographic detection methods also include using an oxido-reductase enzyme (such as horseradish peroxidase) along with a water soluble metal ion, an oxidizing agent and a reducing agent, again to form a detectable precipitate. (See, for example, U.S. Pat. No. 6,670,113).

Probes made using the disclosed methods can be used for nucleic acid detection, such as ISH procedures (for example, fluorescence in situ hybridization (FISH), chromogenic in situ hybridization (CISH) and silver in situ hybridization (SISH)) or comparative genomic hybridization (CGH).

In situ hybridization (ISH) involves contacting a sample containing target nucleic acid sequence (e.g., genomic target nucleic acid sequence) in the context of a metaphase or interphase chromosome preparation (such as a cell or tissue sample mounted on a slide) with a labeled probe specifically hybridizable or specific for the target nucleic acid sequence (e.g., genomic target nucleic acid sequence). The slides are optionally pretreated, e.g., to remove paraffin or other materials that can interfere with uniform hybridization. The sample and the probe are both treated, for example by heating to denature the double stranded nucleic acids. The probe (formulated in a suitable hybridization buffer) and the sample are combined, under conditions and for sufficient time to permit hybridization to occur (typically to reach equilibrium). The chromosome preparation is washed to remove excess probe, and detection of specific labeling of the chromosome target is performed using standard techniques.

For example, a biotinylated probe can be detected using fluorescein-labeled avidin or avidin-alkaline phosphatase. For fluorochrome detection, the fluorochrome can be detected directly, or the samples can be incubated, for example, with fluorescein isothiocyanate (FITC)- conjugated avidin. Amplification of the FITC signal can be effected, if necessary, by incubation with biotin-conjugated goat antiavidin antibodies, washing and a second incubation with FITC- conjugated avidin. For detection by enzyme activity, samples can be incubated, for example, with streptavidin, washed, incubated with biotin-conjugated alkaline phosphatase, washed again and pre-equilibrated (e.g., in alkaline phosphatase (AP) buffer). For a general description of in situ hybridization procedures, see, e.g., U.S. Pat. No. 4,888,278.

Numerous procedures for FISH, CISH, and SISH are known in the art. For example, procedures for performing FISH are described in U.S. Pat. Nos. 5,447,841; 5,472,842; and 5,427,932; and for example, in Pirlkel et al., Proc. Natl. Acad. Sci. 83:2934.2938, 1986; Pinkel et al., Proc. Natl. Acad. Sci. 85:9138-9142, 1988; and Lichter et al., Proc. Natl. Acad. Sci. 85:9664-9668, 1988. CISH is described in, e.g., Tanner et al., Am. .1. Pathol. 157:1467-1472, 2000 and U.S. Pat. No. 6,942,970. Additional detection methods are provided in U.S. Pat. No. 6,280,929.

Numerous reagents and detection schemes can be employed in conjunction with FISH, CISH, and SISH procedures to improve sensitivity, resolution, or other desirable properties. As discussed above probes labeled with fluorophores (including fluorescent dyes and QUANTUM DOTS®) can be directly optically detected when performing FISH. Alternatively, the probe can be labeled with a nonfluorescent molecule, such as a hapten (such as the following nonlimiting examples: biotin, digoxigenin, DNP, and various oxazoles, pyrrazoles, thiazoles, nitroaryls, benzofurazans, triterpenes, ureas, thioureas, rotenones, coumarin, courmarin-based compounds, Podophyllotoxin, Podophyllotoxin-based compounds, and combinations thereof), ligand or other indirectly detectable moiety. Probes labeled with such non-fluorescent molecules (and the target nucleic acid sequences to which they bind) can then be detected by contacting the sample (e.g., the cell or tissue sample to which the probe is bound) with a labeled detection reagent, such as an antibody (or receptor, or other specific binding partner) specific for the chosen hapten or ligand. The detection reagent can be labeled with a fluorophore (e.g., QUANTUM DOT®) or with another indirectly detectable moiety, or can be contacted with one or more additional specific binding agents (e.g., secondary or specific antibodies), which can be labeled with a fluorophore.

In other examples, the probe, or specific binding agent (such as an antibody, e.g., a primary antibody, receptor or other binding agent) is labeled with an enzyme that is capable of converting a fluorogenic or chromogenic composition into a detectable fluorescent, colored or otherwise detectable signal (e.g., as in deposition of detectable metal particles in SISH). As indicated above, the enzyme can be attached directly or indirectly via a linker to the relevant probe or detection reagent. Examples of suitable reagents (e.g., binding reagents) and chemistries (e.g., linker and attachment chemistries) are described in U.S. Patent Application Publication Nos. 2006/0246524; 2006/0246523, and 2007/ 01 17153.

It will be appreciated by those of skill in the art that by appropriately selecting labelled probe-specific binding agent pairs, multiplex detection schemes can he produced to facilitate detection of multiple target nucleic acid sequences (e.g., genomic target nucleic acid sequences) in a single assay (e.g., on a single cell or tissue sample or on more than one cell or tissue sample). For example, a first probe that corresponds to a first target sequence can he labelled with a first hapten, such as biotin, while a second probe that corresponds to a second target sequence can be labelled with a second hapten, such as DNP. Following exposure of the sample to the probes, the bound probes can he detected by contacting the sample with a first specific binding agent (in this case avidin labelled with a first fluorophore, for example, a first spectrally distinct QUANTUM DOT®, e.g., that emits at 585 nm) and a second specific binding agent (in this case an anti-DNP antibody, or antibody fragment, labelled with a second fluorophore (for example, a second spectrally distinct QUANTUM DOT®, e.g., that emits at 705 nm). Additional probes/binding agent pairs can he added to the multiplex detection scheme using other spectrally distinct fluorophores. Numerous variations of direct, and indirect (one step, two step or more) can he envisioned, all of which are suitable in the context of the disclosed probes and assays.

Probes typically comprise single-stranded nucleic acids of between 10 to 1000 nucleotides in length, for instance of between 10 and 800, more preferably of between 15 and 700, typically of between 20 and 500. Primers typically are shorter single-stranded nucleic acids, of between 10 to 25 nucleotides in length, designed to perfectly or almost perfectly match a nucleic acid of interest, to be amplified. The probes and primers are “specific” to the nucleic acids they hybridize to, i.e. they preferably hybridize under high stringency hybridization conditions (corresponding to the highest melting temperature Tm, e.g., 50 % formamide, 5x or 6x SCC. SCC is a 0.15 M NaCl, 0.015 M Na-citrate).

The nucleic acid primers or probes used in the above amplification and detection method may be assembled as a kit. Such a kit includes consensus primers and molecular probes. A preferred kit also includes the components necessary to determine if amplification has occurred. The kit may also include, for example, PCR buffers and enzymes; positive control sequences, reaction control primers; and instructions for amplifying and detecting the specific sequences.

In a particular embodiment, the methods of the invention comprise the steps of providing total RNAs extracted from cumulus cells and subjecting the RNAs to amplification and hybridization to specific probes, more particularly by means of a quantitative or semi- quantitative RT-PCR (or q RT-PCR).

In another preferred embodiment, the expression level is determined by DNA chip analysis. Such DNA chip or nucleic acid microarray consists of different nucleic acid probes that are chemically attached to a substrate, which can be a microchip, a glass slide or a microsphere-sized bead. A microchip may be constituted of polymers, plastics, resins, polysaccharides, silica or silica-based materials, carbon, metals, inorganic glasses, or nitrocellulose. Probes comprise nucleic acids such as cDNAs or oligonucleotides that may be about 10 to about 60 base pairs. To determine the expression level, a sample from a test subject, optionally first subjected to a reverse transcription, is labelled and contacted with the microarray in hybridization conditions, leading to the formation of complexes between target nucleic acids that are complementary to probe sequences attached to the microarray surface. The labelled hybridized complexes are then detected and can be quantified or semi-quantified. Labelling may be achieved by various methods, e.g. by using radioactive or fluorescent labelling. Many variants of the microarray hybridization technology are available to the man skilled in the art (see e.g. the review by Hoheisel, Nature Reviews, Genetics, 2006, 7:200-210).

Expression level of a gene may be expressed as absolute expression level or normalized expression level. Typically, expression levels are normalized by correcting the absolute expression level of a gene by comparing its expression to the expression of a gene that is not a relevant for determining the cancer stage of the patient, e.g., a housekeeping gene that is constitutively expressed. Suitable genes for normalization include housekeeping genes such as the actin gene ACTB, ribosomal 18S gene, GUSB, PGK1, TFRC, GAPDH, GUSB, TBP and ABL1. This normalization allows the comparison of the expression level in one sample, e.g., a patient sample, to another sample, or between samples from different sources. According to the invention, the level of ICOSL proteins, such as ICOSL 4 protein, may also be measured and can be performed by a variety of techniques well known in the art. For measuring the expression level of ICOSL 4, techniques like ELISA (see below) allowing to measure the level of the soluble proteins are particularly suitable.

In the present application, the “level of protein” or the “protein level expression” or the “protein concentration” means the quantity or concentration of said protein. In another embodiment, the “level of protein” means the level of ICOSL 4 proteins fragments. In still another embodiment, the “level of protein” means the quantitative measurement of ICOSL 4 proteins expression relative to a negative control.

According to the invention, the protein level of ICOSL 4 may be measured at the surface of the tumor cells or in an extracellular context (for example in blood or plasma).

Typically protein concentration may be measured for example by capillary electrophoresis-mass spectroscopy technique (CE-MS) or ELISA performed on the sample.

Such methods comprise contacting a sample with a binding partner capable of selectively interacting with proteins present in the sample. The binding partner is generally an antibody that may be polyclonal or monoclonal, preferably monoclonal.

The presence of the protein can be detected using standard electrophoretic and immunodiagnostic techniques, including immunoassays such as competition, direct reaction, or sandwich type assays. Such assays include, but are not limited to, Western blots; agglutination tests; enzyme-labeled and mediated immunoassays, such as ELISAs; biotin/avidin type assays; radioimmunoassays; immunoelectrophoresis; immunoprecipitation, capillary electrophoresismass spectroscopy technique (CE-MS). etc. The reactions generally include revealing labels such as fluorescent, chemioluminescent, radioactive, enzymatic labels or dye molecules, or other methods for detecting the formation of a complex between the antigen and the antibody or antibodies reacted therewith.

The aforementioned assays generally involve separation of unbound protein in a liquid phase from a solid phase support to which antigen-antibody complexes are bound. Solid supports which can be used in the practice of the invention include substrates such as nitrocellulose (e. g., in membrane or microtiter well form); polyvinylchloride (e. g., sheets or microtiter wells); polystyrene latex (e.g., beads or microtiter plates); polyvinylidine fluoride; diazotized paper; nylon membranes; activated beads, magnetically responsive beads, and the like. More particularly, an ELISA method can be used, wherein the wells of a microtiter plate are coated with a set of antibodies against the proteins to be tested. A sample containing or suspected of containing the marker protein is then added to the coated wells. After a period of incubation sufficient to allow the formation of antibody-antigen complexes, the plate(s) can be washed to remove unbound moieties and a detectably labeled secondary binding molecule is added. The secondary binding molecule is allowed to react with any captured sample marker protein, the plate is washed and the presence of the secondary binding molecule is detected using methods well known in the art.

Methods of the invention may comprise a step consisting of comparing the proteins and fragments concentration in circulating cells with a control value. As used herein, "concentration of protein" refers to an amount or a concentration of a transcription product, for instance the proteins ICOSL 4. Typically, a level of a protein can be expressed as nanograms per microgram of tissue or nanograms per milliliter of a culture medium, for example. Alternatively, relative units can be employed to describe a concentration. In a particular embodiment, "concentration of proteins" may refer to fragments of the protein ICOSL 4. Thus, in a particular embodiment, fragment of ICOSL protein, in particular ICOSL 4 protein, may also be measured.

In a particular embodiment, the detection of the level of ICOSL, in particular ICOSL 4, can be performed by flow cytometry. When this method is used, the method consists of determining the amount of ICOSL, in particular ICOSL 4, expressed on tumor cells. According to the invention and the flow cytometry method, when the florescence intensity is high or bright, the level of ICOSL, in particular ICOSL 4, express on tumor cells is high and thus the expression level of ICOSL, in particular ICOSL 4, is high and when the florescence intensity is low or dull, the level of ICOSL, in particular ICOSL 4, express on tumor cells is low and thus the expression level of ICOSL, in particular ICOSL 4, is low.

In another embodiment, the intracellular part of the ICOSL 4 protein is detected. Particularly, the proline riche sequence repeated twice of the ICOSL 4.2 is detected.

In a particular embodiment, the ICOSL 4.2 is detected by PCR or western blot.

Predetermined reference values used for comparison of the expression levels may comprise “cut-off’ or “threshold” values that may be determined as described herein. Each reference (“cut-off’) value for ICOSL level , in particular ICOSL 4 level, may be predetermined by carrying out a method comprising the steps of a) providing a collection of samples from patients suffering of a PTCL or not; b) determining the level of ICOSL, in particular ICOSL 4, for each sample contained in the collection provided at step a); c) ranking the tumor tissue samples according to said level and their status (PTCL or healthy); d) determining the median level of ICOSL, in particular ICOSL 4, for the healthy patients;

I) determining the Predetermined reference value for the PTCL patient by applying statistical test.

The reference value is selected such as the discrimination based on the criterion of the minimum p value is the strongest. In other terms, the expression level corresponding to the boundary between both subsets for which the p value is minimum is considered as the reference value. It should be noted that the reference value is not necessarily the median value of expression levels.

In routine work, the reference value (cut-off value) may be used in the present method to discriminate PTCL samples and therefore the corresponding patients.

The man skilled in the art also understands that the same technique of assessment of the expression level of a protein should of course be used for obtaining the reference value and thereafter for assessment of the expression level of a protein of a patient subjected to the method of the invention.

Such predetermined reference values of expression level may be determined for any protein defined above.

According to the invention, the reference values for ICOSL 4 may be 500 (UA) (reference value obtained with a flow cytometer).

A further object of the invention relates to kits for performing the methods of the invention, wherein said kits comprise means for measuring the expression level of ICOSL, in particular ICOSL 4, and more particularly ICOSL 4.1 and/or 4.2 in the sample obtained from the patient.

Particularly, the kit may comprise specific an antibody targeting ICOSL 4. 1 or ICOSL 4.2.

The kits may include probes, primers macroarrays or microarrays as above described. For example, the kit may comprise a set of probes as above defined, usually made of DNA, and that may be pre-labelled. Alternatively, probes may be unlabelled and the ingredients for labelling may be included in the kit in separate containers. The kit may further comprise hybridization reagents or other suitably packaged reagents and materials needed for the particular hybridization protocol, including solid-phase matrices, if applicable, and standards. Alternatively the kit of the invention may comprise amplification primers that may be prelabelled or may contain an affinity purification or attachment moiety. The kit may further comprise amplification reagents and also other suitably packaged reagents and materials needed for the particular amplification protocol.

In another particular embodiment, a step of communicating the result to the patient may be added to all the methods of the invention.

In some embodiments, all the methods of the invention are performed in vitro or ex vivo.

Therapeutic application

A second aspect of the invention relates to a fusion protein ICOS-Fc for use in the treatment of a Peripheral T-cell lymphoma (PTCL) in a subject in need thereof.

In a particular embodiment, the PTCL is a cutaneous T-cell lymphomas (CTCL) like a Sezary syndrome.

The use of a fusion protein ICOS-Fc is a new therapeutic approach, which makes it possible to overcome the different isoforms of ICOSL expressed in vivo and to overcome variable immunoreactivity with existing monoclonal antibodies anti-ICOS.

Accordingly, the present invention also relates to a method of treating a PTCL in a subject in need thereof comprising administering to the subject a therapeutically effective amount of the fusion protein of the present invention.

As use herein the terms “fusion protein ICOS-Fc” denotes fusion the ICOS receptor and a Fc region of an immunoglobulin. In other words, the term “fusion protein ICOS-Fc” denotes a protein comprising inducible T cell costimulatory (ICOS) receptor fused to a Fc region of an immunoglobulin. The ICOS receptor and the Fc region can be bind by a linker or not and the linker can be a peptide linker or not. The ICOS receptor and the Fc region can be bind by a covalent link.

In a particular embodiment, the ICOS receptor is fused to the Fc region at its N terminal end or at its C terminal end.

According to the invention, the ICOS receptor is a recombinant ICOS receptor.

Accordingly, in some embodiment the fusion protein ICOS-Fc can be administered to a subject diagnosed with PTCL according to the invention. Thus, in some embodiment, the invention refers to a method of treating a PTCL in a subject in need thereof comprising administering to the subject a therapeutically effective amount of the fusion protein ICOS-Fc of the present invention when the subject is diagnosed with PTCL according to the invention.

In other words, in some embodiment, the invention refers to a method of treating a PTCL in a subject in need thereof comprising i) determining in a sample obtained from the patient the expression level ICOSL 4 ii) comparing the expression level determined at step i) with its predetermined reference value and iii) administering to the subject a therapeutically effective amount of the fusion protein ICOS-Fc of the present invention when the expression level determined at step i) is higher than its predetermined reference value.

As used herein the term "antibody" or "immunoglobulin" have the same meaning and will be used equally in the present invention. The term "antibody" as used herein refers to immunoglobulin molecules and immunologically active portions of immunoglobulin molecules, i.e., molecules that contain an antigen binding site that immunospecifically binds an antigen. As such, the term antibody encompasses not only whole antibody molecules, but also antibody fragments as well as variants (including derivatives) of antibodies and antibody fragments. In natural antibodies, two heavy chains are linked to each other by disulfide bonds and each heavy chain is linked to a light chain by a disulfide bond. There are two types of light chain, lambda (1) and kappa (k). There are five main heavy chain classes (or isotypes) which determine the functional activity of an antibody molecule: IgM, IgD, IgG, IgA and IgE. Each chain contains distinct sequence domains. The light chain includes two domains, a variable domain (VL) and a constant domain (CL). The heavy chain includes four domains, a variable domain (VH) and three constant domains (CHI, CH2 and CH3, collectively referred to as CH). The variable regions of both light (VL) and heavy (VH) chains determine binding recognition and specificity to the antigen. The constant region domains of the light (CL) and heavy (CH) chains confer important biological properties such as antibody chain association, secretion, trans-placental mobility, complement binding, and binding to Fc receptors (FcR). The Fv fragment is the N-terminal part of the Fab fragment of an immunoglobulin and consists of the variable portions of one light chain and one heavy chain. The specificity of the antibody resides in the structural complementarity between the antibody combining site and the antigenic determinant. Antibody combining sites are made up of residues that are primarily from the hypervariable or complementarity determining regions (CDRs). Occasionally, residues from nonhypervariable or framework regions (FR) can participate to the antibody binding site or influence the overall domain structure and hence the combining site. Complementarity Determining Regions or CDRs refer to amino acid sequences which together define the binding affinity and specificity of the natural Fv region of a native immunoglobulin binding site. The light and heavy chains of an immunoglobulin each have three CDRs, designated L-CDR1, L- CDR2, L- CDR3 and H-CDR1, H-CDR2, H-CDR3, respectively. An antigen-binding site, therefore, typically includes six CDRs, comprising the CDR set from each of a heavy and a light chain V region. Framework Regions (FRs) refer to amino acid sequences interposed between CDRs.

In some embodiments, the Fc region is altered by replacing at least one amino acid residue with a different amino acid residue to alter the effector functions of the antibody. For example, one or more amino acids can be replaced with a different amino acid residue such that the fusion protein has an altered affinity for an effector ligand but retains the antigen-binding ability of the ICOS receptor. The effector ligand to which affinity is altered can be, for example, an Fc receptor or the Cl component of complement. This approach is described in further detail in U.S. Patent Nos. 5,624,821 and 5,648,260, both by Winter et al.

In some embodiments, the Fc region is modified to increase the ability of the fusion protein to mediate antibody dependent cellular cytotoxicity (ADCC or ADCC-like) or Antibody-dependent cellular phagocytosis (ADCP or ADCP-like) and/or to increase the affinity of the fusion protein for an Fc receptor by modifying one or more amino acids. This approach is described further in PCT Publication WO 00/42072 by Presta. Moreover, the binding sites on human IgGI for FcyRI, FcyRII, FcyRIII and FcRn have been mapped and variants with improved binding have been described (see Shields, R. L. et al., 2001 J. Biol. Chen. 276:6591- 6604, W02010106180).

The term "antibody-dependent cell-mediated cytotoxicity" or "ADCC" is a term well understood in the art and refers to a cell-mediated reaction in which non- specific cytotoxic cells that express Fc receptors (FcRs) recognize bound antibody on a target cell and subsequently cause lysis of the target cell. Non-specific cytotoxic cells that mediate ADCC include natural killer (NK) cells, macrophages, monocytes, neutrophils, and eosinophils.

As used herein, the term "effector functions" refer to those biological activities attributable to the Fc region of an antibody, which vary with the antibody isotype. Examples of antibody effector functions include: Clq binding and complement dependent cytotoxicity (CDC); Fc receptor binding; antibody-dependent cell-mediated cytotoxicity (ADCC); phagocytosis; down regulation of cell surface receptors (e.g. B cell receptor); and B cell activation.

In a particular embodiment, the Fc region is obtained from an IgGl.

In a particular embodiment, the ICOS receptor can be modified to reduce its amino acid sequence but retain the ability to specifically binds to ICOSL.

In a particular embodiment, the ICOS part of the fusion protein ICOS-Fc correspond to the ICOS extracellular domain. According to the invention, the ICOS extracellular domain is fuse to the Fc if an Iggl by a linker.

In a particular embodiment the ICOS part of the fusion protein ICOS-Fc has an amino acid sequence a set forth in SEQ ID NO:3:

EINGS ANYEMFIFHNGGVQILCKYPDIVQQFKMQLLKGGQILCDLTKTKGSGN TVSIKSLKFCHSQLSNNSVSFFLYNLDHSHANYYFCNLSIFDPPPFKVTLTGGYLHIYE SQLCCQLKF

In a particular embodiment, the ICOS extracellular domain and the linker has an amino acid sequence a set forth in SEQ ID NO:4 (ICOS extracellular doma -Z/wA :

EINGS ANYEMFIFHNGGVQILCKYPDIVQQFKMQLLKGGQILCDLTKTKGSGN TVSIKSLKFCHSQLSNNSVSFFLYNLDHSHANYYFCNLSIFDPPPFKVTLTGGYLHIYE SQLCCQLKF -IEGRMD

According to the invention, the SEQ ID NO:4 is fused to an Fc region of an IgGl (human IgGl pro!00-Lys330) to obtain the fusion protein ICOS-Fc. Thus, in a particular embodiment, the fusion protein ICOS-Fc has an amino acid sequence a set forth in SEQ ID NO: 5 (ICOS extracellular domain-Zitifer-Fc region) :

EINGS ANYEMFIFHNGGVQILCKYPDIVQQFKMQLLKGGQILCDLTKTKGSGN TVSIKSLKFCHSQLSNNSVSFFLYNLDHSHANYYFCNLSIFDPPPFKVTLTGGYLHIYE SOLCCOLKF-/EG D-PKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEV TCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEOYNSTYRVVSVLTVLHQDWL NGKEYKCKVSNKALPAPIEKTISKAKGOPREPQVYTLPPSRDELTKNOVSLTCLVKGF YPSDIAVEWESNGOPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWOQGNVFSCSVMH EALHNHYTQKSLSLSPGK As used herein, the term “specificity” refers to the ability of an antibody to detectably bind an epitope presented on an antigen, such as ICOS, while having relatively little detectable reactivity with non-ICOS proteins or structures. Specificity can be relatively determined by binding or competitive binding assays, using, e.g., Biacore instruments, as described elsewhere herein. Specificity can be exhibited by, e.g., an about 10:1, about 20: 1, about 50: 1, about 100: 1, 10.000: 1 or greater ratio of affmity/avidity in binding to the specific antigen versus nonspecific binding to other irrelevant molecules (in this case the specific antigen is ICOS).

The term “affinity”, as used herein, means the strength of the binding of an antibody to an epitope. The affinity of an antibody is given by the dissociation constant Kd, defined as [Ab] ^x [ Ag] / [Ab-Ag], where [Ab-Ag] is the molar concentration of the antibody-antigen complex, [Ab] is the molar concentration of the unbound antibody and [Ag] is the molar concentration of the unbound antigen. The affinity constant Ka is defined by 1/Kd. Preferred methods for determining the affinity of mAbs can be found in Harlow, et al., Antibodies: A Laboratory Manual, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., 1988), Coligan et al., eds., Current Protocols in Immunology, Greene Publishing Assoc, and Wiley Interscience, N.Y., (1992, 1993), and Muller, Meth. Enzymol. 92:589-601 (1983), which references are entirely incorporated herein by reference. One preferred and standard method well known in the art for determining the affinity of mAbs is the use of Biacore instruments.

In certain embodiments of the invention the fusion protein has been engineered to increase pl (isoelectric point) and improve their drug-like properties. The pl of a protein is a key determinant of the overall biophysical properties of a molecule. Fusion protein that have low pls have been known to be less soluble, less stable, and prone to aggregation. Further, the purification of fusion protein with low pl is challenging and can be problematic especially during scale-up for clinical use. Increasing the pl of the fusion protein of the invention improved their solubility, enabling the antibodies to be formulated at higher concentrations (>100 mg/ml). Formulation of the fusion protein at high concentrations (e.g. >100mg/ml) offers the advantage of being able to administer higher doses of the fusion protein into eyes of patients via intravitreal injections, which in turn may enable reduced dosing frequency, a significant advantage for treatment of chronic diseases including cardiovascular disorders. Higher pls may also increase the FcRn- mediated recycling of the IgG version of the antibody thus enabling the drug to persist in the body for a longer duration, requiring fewer injections. Finally, the overall stability of the fusion protein is significantly improved due to the higher pi resulting in longer shelf-life and bioactivity in vivo. Preferably, the pl is greater than or equal to 8.2. In each of the embodiments of the treatment methods described above, the fusion protein of the invention is delivered in a manner consistent with conventional methodologies associated with management of the disease or disorder for which treatment is sought. In accordance with the disclosure herein, an effective amount of the antibody or antibody-drug conjugate is administered to a patient in need of such treatment for a time and under conditions sufficient to prevent or treat the disease or disorder.

As used herein, the term "treatment" or "treat" refer to both prophylactic or preventive treatment as well as curative or disease modifying treatment, including treatment of subjects at risk of contracting the disease or suspected to have contracted the disease as well as subjects who are ill or have been diagnosed as suffering from a disease or medical condition, and includes suppression of clinical relapse. The treatment may be administered to a subject having a medical disorder or who ultimately may acquire the disorder, in order to prevent, cure, delay the onset of, reduce the severity of, or ameliorate one or more symptoms of a disorder or recurring disorder, or in order to prolong the survival of a subject beyond that expected in the absence of such treatment. By "therapeutic regimen" is meant the pattern of treatment of an illness, e.g., the pattern of dosing used during therapy. A therapeutic regimen may include an induction regimen and a maintenance regimen. The phrase "induction regimen" or "induction period" refers to a therapeutic regimen (or the portion of a therapeutic regimen) that is used for the initial treatment of a disease. The general goal of an induction regimen is to provide a high level of drug to a subject during the initial period of a treatment regimen. An induction regimen may employ (in part or in whole) a "loading regimen", which may include administering a greater dose of the drug than a physician would employ during a maintenance regimen, administering a drug more frequently than a physician would administer the drug during a maintenance regimen, or both. The phrase "maintenance regimen" or "maintenance period" refers to a therapeutic regimen (or the portion of a therapeutic regimen) that is used for the maintenance of a subject during treatment of an illness, e.g., to keep the subject in remission for long periods of time (months or years). A maintenance regimen may employ continuous therapy (e.g., administering a drug at a regular intervals, e.g., weekly, monthly, yearly, etc.) or intermittent therapy (e.g., interrupted treatment, intermittent treatment, treatment at relapse, or treatment upon achievement of a particular predetermined criteria [e.g., disease manifestation, etc.]).

As used herein, the term "therapeutically effective amount" or “effective amount” refers to an amount effective, at dosages and for periods of time necessary, to achieve a desired therapeutic result. A therapeutically effective amount of the fusion protein of the present invention may vary according to factors such as the disease state, age, sex, and weight of the individual, and the ability of the fusion protein of the present invention to elicit a desired response in the individual. A therapeutically effective amount is also one in which any toxic or detrimental effects of the fusion protein is outweighed by the therapeutically beneficial effects. The efficient dosages and dosage regimens for the fusion protein of the present invention depend on the disease or condition to be treated and may be determined by the persons skilled in the art. A physician having ordinary skill in the art may readily determine and prescribe the effective amount of the pharmaceutical composition required. For example, the physician could start doses of the fusion protein of the present invention employed in the pharmaceutical composition at levels lower than that required in order to achieve the desired therapeutic effect and gradually increase the dosage until the desired effect is achieved. In general, a suitable dose of a composition of the present invention will be that amount of the compound which is the lowest dose effective to produce a therapeutic effect according to a particular dosage regimen. Such an effective dose will generally depend upon the factors described above. For example, a therapeutically effective amount for therapeutic use may be measured by its ability to stabilize the progression of disease. Typically, the ability of a compound to inhibit cancer may, for example, be evaluated in an animal model system predictive of efficacy in human tumors. Alternatively, this property of a composition may be evaluated by examining the ability of the compound to induce cytotoxicity by in vitro assays known to the skilled practitioner. A therapeutically effective amount of a therapeutic compound may decrease tumor size, or otherwise ameliorate symptoms in a subject. One of ordinary skill in the art would be able to determine such amounts based on such factors as the subject's size, the severity of the subject's symptoms, and the particular composition or route of administration selected. An exemplary, non-limiting range for a therapeutically effective amount of the fusion protein of the present invention is about 0.1-100 mg/kg, such as about 0.1-50 mg/kg, for example about 0.1 -20 mg/kg, such as about 0.1-10 mg/kg, for instance about 0.5, about such as 0.3, about 1, about 3 mg/kg, about 5 mg/kg or about 8 mg/kg. An exemplary, non-limiting range for a therapeutically effective amount of the fusion protein of the present invention is 0.02-100 mg/kg, such as about 0.02-30 mg/kg, such as about 0.05-10 mg/kg or 0.1-3 mg/kg, for example about 0.5-2 mg/kg. Administration may e.g. be intravenous, intramuscular, intraperitoneal, or subcutaneous, and for instance administered proximal to the site of the target. Dosage regimens in the above methods of treatment and uses are adjusted to provide the optimum desired response (e.g., a therapeutic response). For example, a single bolus may be administered, several divided doses may be administered over time or the dose may be proportionally reduced or increased as indicated by the exigencies of the therapeutic situation. In some embodiments, the efficacy of the treatment is monitored during the therapy, e.g. at predefined points in time. In some embodiments, the efficacy may be monitored by visualization of the disease area, or by other diagnostic methods described further herein, e.g. by performing one or more PET-CT scans, for example using a labeled fusion protein of the present invention. If desired, an effective daily dose of a pharmaceutical composition may be administered as two, three, four, five, six or more sub-doses administered separately at appropriate intervals throughout the day, optionally, in unit dosage forms. In some embodiments, the fusion proteinf the present invention is administered by slow continuous infusion over a long period, such as more than 24 hours, in order to minimize any unwanted side effects. An effective dose of the fusion protein of the present invention may also be administered using a weekly, biweekly or triweekly dosing period. The dosing period may be restricted to, e.g., 8 weeks, 12 weeks or until clinical progression has been established. As non-limiting examples, treatment according to the present invention may be provided as a daily dosage of the fusion protein of the present invention in an amount of about 0.1-100 mg/kg, such as 0.2, 0.5, 0.9, 1.0, 1.1, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 40, 45, 50, 60, 70, 80,

90 or 100 mg/kg, per day, on at least one of days 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,

16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, or 40, or alternatively, at least one of weeks 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,

18, 19 or 20 after initiation of treatment, or any combination thereof, using single or divided doses every 24, 12, 8, 6, 4, or 2 hours, or any combination thereof.

Accordingly, one object of the present invention relates to a method of treating a PTCLin a subject in need thereof comprising administering to the subject a therapeutically effective amount of the fusion protein of the present invention.

In a particular embodiment, the fusion protein of the invention is used in combination with a second agent for the treatment of a PTCL. Conventional cancer therapies such as, e.g., surgery, radiotherapy, chemotherapy, or combinations thereof can be used.

The present invention also provides for therapeutic applications where the fusion protein of the present invention is used in combination with at least one further therapeutic agent, e.g. for treating PTCL. Such administration may be simultaneous, separate or sequential. For simultaneous administration the agents may be administered as one composition or as separate compositions, as appropriate. The further therapeutic agent is typically relevant for the disorder to be treated. Exemplary therapeutic agents include other anti-cancer antibodies, cytotoxic agents, chemotherapeutic agents, anti-angiogenic agents, anti-cancer immunogens, cell cycle control/apoptosis regulating agents, hormonal regulating agents, and other agents described below.

In some embodiments, the fusion protein of the present invention is used in combination with a chemotherapeutic agent. The term "chemotherapeutic agent" refers to chemical compounds that are effective in inhibiting tumor growth. Examples of chemotherapeutic agents include alkylating agents such as thiotepa and cyclosphosphamide; alkyl sulfonates such as busulfan, improsulfan and piposulfan; aziridines such as benzodopa, carboquone, meturedopa, and uredopa; ethylenimines and methylamelamines including altretamine, triethylenemelamine, trietylenephosphoramide, triethylenethiophosphaoramide and trimethylolomelamine; acetogenins (especially bullatacin and bullatacinone); a camptothecin (including the synthetic analogue topotecan); bryostatin; callystatin; CC-1065 (including its adozelesin, carzelesin and bizelesin synthetic analogues); cryptophycins (particularly cryptophycin 1 and cryptophycin 8); dolastatin; duocarmycin (including the synthetic analogues, KW-2189 and CBI-TMI); eleutherobin; pancratistatin; a sarcodictyin; spongistatin; nitrogen mustards such as chlorambucil, chlomaphazine, cholophosphamide, estramustine, ifosfamide, mechlorethamine, mechlorethamine oxide hydrochloride, melphalan, novembichin, phenesterine, prednimus tine, trofosfamide, uracil mustard; nitrosureas such as carmustine, chlorozotocin, fotemustine, lomustine, nimustine, ranimustine; antibiotics such as the enediyne antibiotics (e.g. calicheamicin, especially calicheamicin (11 and calicheamicin 211, see, e.g., Agnew Chem Inti. Ed. Engl. 33:183-186 (1994); dynemicin, including dynemicin A; an esperamicin; as well as neocarzinostatin chromophore and related chromoprotein enediyne antiobiotic chromomophores), aclacinomysins, actinomycin, authramycin, azaserine, bleomycins, cactinomycin, carabicin, canninomycin, carzinophilin, chromomycins, dactinomycin, daunorubicin, detorubicin, 6-diazo-5-oxo-L-norleucine, doxorubicin (including morpholino-doxorubicin, cyanomorpholino-doxorubicin, 2-pyrrolino-doxorubicin and deoxydoxorubicin), epirubicin, esorubicin, idanrbicin, marcellomycin, mitomycins, mycophenolic acid, nogalamycin, olivomycins, peplomycin, potfiromycin, puromycin, quelamycin, rodorubicin, streptomgrin, streptozocin, tubercidin, ubenimex, zinostatin, zorubicin; anti-metabolites such as methotrexate and 5 -fluorouracil (5-FU); folic acid analogues such as denopterin, methotrexate, pteropterin, trimetrexate; purine analogs such as fludarabine, 6-mercaptopurine, thiamiprine, thioguanine; pyrimidine analogs such as ancitabine, azacitidine, 6-azauridine, carmofur, cytarabine, dideoxyuridine, doxifluridine, enocitabine, floxuridine, 5-FU; androgens such as calusterone, dromostanolone propionate, epitiostanol, mepitiostane, testolactone; anti-adrenals such as aminoglutethimide, mitotane, trilostane; folic acid replenisher such as frolinic acid; aceglatone; aldophosphamide glycoside; aminolevulinic acid; amsacrine; bestrabucil; bisantrene; edatraxate; defofamine; demecolcine; diaziquone; elfomithine; elliptinium acetate; an epothilone; etoglucid; gallium nitrate; hydroxyurea; lentinan; lonidamine; maytansinoids such as maytansine and ansamitocins; mitoguazone; mitoxantrone; mopidamol; nitracrine; pento statin; phenamet; pirarubicin; podophyllinic acid; 2-ethylhydrazide; procarbazine; PSK®; razoxane; rhizoxin; sizofiran; spirogennanium; tenuazonic acid; triaziquone; 2, 2', 2" -tri chlorotri ethylamine; trichothecenes (especially T-2 toxin, verracurin A, roridinA and anguidine); urethan; vindesine; dacarbazine; mannomustine; mitobromtol; mitolactol; pipobroman; gacytosine; arabinoside ("Ara-C"); cyclophosphamide; thiotepa; taxoids, e.g. paclitaxel (TAXOL®, Bristol-Myers Squibb Oncology, Princeton, N.].) and doxetaxel (TAXOTERE®, Rhone-Poulenc Rorer, Antony, France); chlorambucil; gemcitabine; 6-thioguanine; mercaptopurine; methotrexate; platinum analogs such as cisplatin and carboplatin; vinblastine; platinum; etoposide (VP- 16); ifosfamide; mitomycin C; mitoxantrone; vincristine; vinorelbine; navelbine; novantrone; teniposide; daunomycin; aminopterin; xeloda; ibandronate; CPT-1 1 ; topoisomerase inhibitor RFS 2000; difluoromethylomithine (DMFO); retinoic acid; capecitabine; and pharmaceutically acceptable salts, acids or derivatives of any of the above. Also included in this definition are antihormonal agents that act to regulate or inhibit honnone action on tumors such as anti-estrogens including for example tamoxifen, raloxifene, aromatase inhibiting 4(5)-imidazoles, 4-hy dr oxy tamoxifen, trioxifene, keoxifene, LY117018, onapristone, and toremifene (Fareston); and anti-androgens such as flutamide, nilutamide, bicalutamide, leuprolide, and goserelin; and pharmaceutically acceptable salts, acids or derivatives of any of the above.

In some embodiments, the fusion protein of the present invention is used in combination with a targeted cancer therapy. Targeted cancer therapies are drugs or other substances that block the growth and spread of cancer by interfering with specific molecules ("molecular targets") that are involved in the growth, progression, and spread of cancer. Targeted cancer therapies are sometimes called "molecularly targeted drugs," "molecularly targeted therapies," "precision medicines," or similar names. In some embodiments, the targeted therapy consists of administering the subject with a tyrosine kinase inhibitor. The term “tyrosine kinase inhibitor” refers to any of a variety of therapeutic agents or drugs that act as selective or non- selective inhibitors of receptor and/or non-receptor tyrosine kinases. Tyrosine kinase inhibitors and related compounds are well known in the art and described in U.S Patent Publication 2007/0254295, which is incorporated by reference herein in its entirety. It will be appreciated by one of skill in the art that a compound related to a tyrosine kinase inhibitor will recapitulate the effect of the tyrosine kinase inhibitor, e.g., the related compound will act on a different member of the tyrosine kinase signaling pathway to produce the same effect as would a tyrosine kinase inhibitor of that tyrosine kinase. Examples of tyrosine kinase inhibitors and related compounds suitable for use in methods of embodiments of the present invention include, but are not limited to, dasatinib (BMS-354825), PP2, BEZ235, saracatinib, gefitinib (Iressa), sunitinib (Sutent; SU11248), erlotinib (Tarceva; OSI-1774), lapatinib (GW572016; GW2016), canertinib (CI 1033), semaxinib (SU5416), vatalanib (PTK787/ZK222584), sorafenib (BAY 43-9006), imatinib (Gleevec; STI571), leflunomide (SU101), vandetanib (Zactima; ZD6474), MK-2206 (8-[4-aminocyclobutyl)phenyl]-9-phenyl-l,2,4-triazolo[3,4-f| [l,6]naphthyridin- 3(2H)-one hydrochloride) derivatives thereof, analogs thereof, and combinations thereof. Additional tyrosine kinase inhibitors and related compounds suitable for use in the present invention are described in, for example, U.S Patent Publication 2007/0254295, U.S. Pat. Nos. 5,618,829, 5,639,757, 5,728,868, 5,804,396, 6,100,254, 6,127,374, 6,245,759, 6,306,874, 6,313,138, 6,316,444, 6,329,380, 6,344,459, 6,420,382, 6,479,512, 6,498,165, 6,544,988, 6,562,818, 6,586,423, 6,586,424, 6,740,665, 6,794,393, 6,875,767, 6,927,293, and 6,958,340, all of which are incorporated by reference herein in their entirety. In some embodiments, the tyrosine kinase inhibitor is a small molecule kinase inhibitor that has been orally administered and that has been the subject of at least one Phase I clinical trial, more preferably at least one Phase II clinical, even more preferably at least one Phase III clinical trial, and most preferably approved by the FDA for at least one hematological or oncological indication. Examples of such inhibitors include, but are not limited to, Gefitinib, Erlotinib, Lapatinib, Canertinib, BMS- 599626 (AC-480), Neratinib, KRN-633, CEP-11981, Imatinib, Nilotinib, Dasatinib, AZM- 475271, CP-724714, TAK-165, Sunitinib, Vatalanib, CP-547632, Vandetanib, Bosutinib, Lestaurtinib, Tandutinib, Midostaurin, Enzastaurin, AEE-788, Pazopanib, Axitinib, Motasenib, OSI-930, Cediranib, KRN-951, Dovitinib, Seliciclib, SNS-032, PD-0332991, MKC-I (Ro- 317453; R-440), Sorafenib, ABT-869, Brivanib (BMS-582664), SU-14813, Telatinib, SU- 6668, (TSU-68), L-21649, MLN-8054, AEW-541, and PD-0325901.

In some embodiments, the fusion protein of the present invention is used in combination with an immunotherapeutic agent. The term "immunotherapeutic agent," as used herein, refers to a compound, composition or treatment that indirectly or directly enhances, stimulates or increases the body's immune response against cancer cells and/or that decreases the side effects of other anticancer therapies. Immunotherapy is thus a therapy that directly or indirectly stimulates or enhances the immune system's responses to cancer cells and/or lessens the side effects that may have been caused by other anti-cancer agents. Immunotherapy is also referred to in the art as immunologic therapy, biological therapy biological response modifier therapy and biotherapy. Examples of common immunotherapeutic agents known in the art include, but are not limited to, cytokines, cancer vaccines, monoclonal antibodies and non-cytokine adjuvants. Alternatively the immunotherapeutic treatment may consist of administering the subject with an amount of immune cells (T cells, NK, cells, dendritic cells, B cells... ). Immunotherapeutic agents can be non-specific, i.e. boost the immune system generally so that the human body becomes more effective in fighting the growth and/or spread of cancer cells, or they can be specific, i.e. targeted to the cancer cells themselves immunotherapy regimens may combine the use of non-specific and specific immunotherapeutic agents. Non-specific immunotherapeutic agents are substances that stimulate or indirectly improve the immune system. Non-specific immunotherapeutic agents have been used alone as a main therapy for the treatment of cancer, as well as in addition to a main therapy, in which case the non-specific immunotherapeutic agent functions as an adjuvant to enhance the effectiveness of other therapies (e.g. cancer vaccines). Non-specific immunotherapeutic agents can also function in this latter context to reduce the side effects of other therapies, for example, bone marrow suppression induced by certain chemotherapeutic agents. Non-specific immunotherapeutic agents can act on key immune system cells and cause secondary responses, such as increased production of cytokines and immunoglobulins. Alternatively, the agents can themselves comprise cytokines. Non-specific immunotherapeutic agents are generally classified as cytokines or non-cytokine adjuvants. A number of cytokines have found application in the treatment of cancer either as general non-specific immunotherapies designed to boost the immune system, or as adjuvants provided with other therapies. Suitable cytokines include, but are not limited to, interferons, interleukins and colony-stimulating factors. Interferons (IFNs) contemplated by the present invention include the common types of IFNs, IFN-alpha (IFN-a), IFN-beta (IFN-P) and IFN-gamma (IFN-y). IFNs can act directly on cancer cells, for example, by slowing their growth, promoting their development into cells with more normal behavior and/or increasing their production of antigens thus making the cancer cells easier for the immune system to recognise and destroy. IFNs can also act indirectly on cancer cells, for example, by slowing down angiogenesis, boosting the immune system and/or stimulating natural killer (NK) cells, T cells and macrophages. Recombinant IFN-alpha is available commercially as Roferon (Roche Pharmaceuticals) and Intron A (Schering Corporation). Interleukins contemplated by the present invention include IL-2, IL-4, IL-11 and IL-12. Examples of commercially available recombinant interleukins include Proleukin® (IL-2; Chiron Corporation) and Neumega® (IL-12; Wyeth Pharmaceuticals). Zymogenetics, Inc. (Seattle, Wash.) is currently testing a recombinant form of IL-21, which is also contemplated for use in the combinations of the present invention. Colony-stimulating factors (CSFs) contemplated by the present invention include granulocyte colony stimulating factor (G-CSF or filgrastim), granulocyte-macrophage colony stimulating factor (GM-CSF or sargramostim) and erythropoietin (epoetin alfa, darbepoietin). Treatment with one or more growth factors can help to stimulate the generation of new blood cells in subjects undergoing traditional chemotherapy. Accordingly, treatment with CSFs can be helpful in decreasing the side effects associated with chemotherapy and can allow for higher doses of chemotherapeutic agents to be used. Various-recombinant colony stimulating factors are available commercially, for example, Neupogen® (G-CSF; Amgen), Neulasta (pelfilgrastim; Amgen), Leukine (GM-CSF; Berlex), Procrit (erythropoietin; Ortho Biotech), Epogen (erythropoietin; Amgen), Amesp (erytropoietin). Combination compositions and combination administration methods of the present invention may also involve "whole cell" and "adoptive" immunotherapy methods. For instance, such methods may comprise infusion or re-infusion of immune system cells (for instance tumor-infiltrating lymphocytes (TILs), such as CC2+ and/or CD8+ T cells (for instance T cells expanded with tumor-specific antigens and/or genetic enhancements), antibodyexpressing B cells or other antibody-producing or -presenting cells, dendritic cells (e.g., dendritic cells cultured with a DC-expanding agent such as GM-CSF and/or Flt3-L, and/or tumor-associated antigen-loaded dendritic cells), anti-tumor NK cells, so-called hybrid cells, or combinations thereof. Cell lysates may also be useful in such methods and compositions. Cellular "vaccines" in clinical trials that may be useful in such aspects include Canvaxin™, APC-8015 (Dendreon), HSPPC-96 (Antigenics), and Melacine® cell lysates. Antigens shed from cancer cells, and mixtures thereof (see for instance Bystryn et al., Clinical Cancer Research Vol. 7, 1882-1887, July 2001), optionally admixed with adjuvants such as alum, may also be components in such methods and combination compositions.

In some embodiments, the fusion protein of the present invention is used in combination with radiotherapy. Radiotherapy may comprise radiation or associated administration of radiopharmaceuticals to a patient. The source of radiation may be either external or internal to the patient being treated (radiation treatment may, for example, be in the form of external beam radiation therapy (EBRT) or brachytherapy (BT)). Radioactive elements that may be used in practicing such methods include, e.g., radium, cesium-137, iridium-192, americium-241, gold- 198, cobalt-57, copper-67, technetium-99, iodide-123, iodide-131, and indium-i ll. In some embodiments, the fusion protein of the present invention is used in combination with an antibody that is specific for a costimulatory molecule. Examples of antibodies that are specific for a costimulatory molecule include but are not limited to anti-CTLA4 antibodies (e.g. Ipilimumab), anti-PDl antibodies, anti-PDLl antibodies, anti-TIMP3 antibodies, anti-LAG3 antibodies, anti-B7H3 antibodies, anti-B7H4 antibodies or anti-B7H6 antibodies.

In some embodiments, the second agent is an agent that induces, via ADCC, the death of a cell expressing an antigen to which the second agent binds. In some embodiments, the agent is an antibody (e.g. of IgGl or IgG3 isotype) whose mode of action involves induction of ADCC toward a cell to which the antibody binds. NK cells have an important role in inducing ADCC and increased reactivity of NK cells can be directed to target cells through use of such a second agent. In some embodiments, the second agent is an antibody specific for a cell surface antigens, e.g., membrane antigens. In some embodiments, the second antibody is specific for a tumor antigen as described above (e.g., molecules specifically expressed by tumor cells), such as CD20, CD52, ErbB2 (or HER2/Neu), CD33, CD22, CD25, MUC-1, CEA, KDR, aVp3, etc., particularly lymphoma antigens (e.g., CD20). Accordingly, the present invention also provides methods to enhance the anti-tumor effect of monoclonal antibodies directed against tumor antigen(s). In the methods of the invention, ADCC function is specifically augmented, which in turn enhances target cell killing, by sequential administration of an antibody directed against one or more tumor antigens, and an antibody of the present invention.

Accordingly, a further object relates to a method of enhancing NK cell antibodydependent cellular cytotoxicity (ADCC) of an antibody in a subject in need thereof comprising administering to the subject the antibody and administering to the subject the fusion protein of the present invention.

A number of antibodies are currently in clinical use for the treatment of cancer, and others are in varying stages of clinical development. Antibodies of interest for the methods of the invention act through ADCC, and are typically selective for tumor cells, although one of skill in the art will recognize that some clinically useful antibodies do act on non-tumor cells, e.g. CD20. There are a number of antigens and corresponding monoclonal antibodies for the treatment of B cell malignancies. One popular target antigen is CD20, which is found on B cell malignancies. Rituximab is a chimeric unconjugated monoclonal antibody directed at the CD20 antigen. CD20 has an important functional role in B cell activation, proliferation, and differentiation. The CD52 antigen is targeted by the monoclonal antibody alemtuzumab, which is indicated for treatment of chronic lymphocytic leukemia. CD22 is targeted by a number of antibodies, and has recently demonstrated efficacy combined with toxin in chemotherapy- resistant hairy cell leukemia. Monoclonal antibodies targeting CD20, also include tositumomab and ibritumomab. Monoclonal antibodies useful in the methods of the invention, which have been used in solid tumors, include without limitation edrecolomab and trastuzumab (herceptin). Edrecolomab targets the 17-1 A antigen seen in colon and rectal cancer, and has been approved for use in Europe for these indications. Its antitumor effects are mediated through ADCC, CDC, and the induction of an anti-idiotypic network. Trastuzumab targets the HER- 2/neu antigen. This antigen is seen on 25% to 35% of breast cancers. Trastuzumab is thought to work in a variety of ways: downregulation of HER-2 receptor expression, inhibition of proliferation of human tumor cells that overexpress HER-2 protein, enhancing immune recruitment and ADCC against tumor cells that overexpress HER-2 protein, and downregulation of angiogenesis factors. Alemtuzumab (Campath) is used in the treatment of chronic lymphocytic leukemia; colon cancer and lung cancer; Gemtuzumab (Mylotarg) finds use in the treatment of acute myelogenous leukemia; Ibritumomab (Zevalin) finds use in the treatment of non-Hodgkin's lymphoma; Panitumumab (Vectibix) finds use in the treatment of colon cancer. Cetuximab (Erbitux) is also of interest for use in the methods of the invention. The antibody binds to the EGF receptor (EGFR), and has been used in the treatment of solid tumors including colon cancer and squamous cell carcinoma of the head and neck (SCCHN).

Acid nucleic, vector and host cell

A further object of the invention relates to a nucleic acid molecule encoding a fusion protein according to the invention.

Thus, the present invention relates a nucleic acid molecule encoding a fusion protein according to the invention for use in the treatment of a PTCL in a subject in need thereof.

Typically, said nucleic acid is a DNA or RNA molecule, which may be included in any suitable vector, such as a plasmid, cosmid, episome, artificial chromosome, phage or a viral vector. As used herein, the terms "vector", "cloning vector" and "expression vector" mean the vehicle by which a DNA or RNA sequence (e.g. a foreign gene) can be introduced into a host cell, so as to transform the host and promote expression (e.g. transcription and translation) of the introduced sequence. So, a further aspect of the invention relates to a vector comprising a nucleic acid of the invention. Such vectors may comprise regulatory elements, such as a promoter, enhancer, terminator and the like, to cause or direct expression of said antibody upon administration to a subject. Examples of promoters and enhancers used in the expression vector for animal cell include early promoter and enhancer of SV40 (Mizukami T. et al. 1987), LTR promoter and enhancer of Moloney mouse leukemia virus (Kuwana Y et al. 1987), promoter (Mason JO et al. 1985) and enhancer (Gillies SD et al. 1983) of immunoglobulin H chain and the like. Any expression vector for animal cell can be used, so long as a gene encoding the human antibody C region can be inserted and expressed. Examples of suitable vectors include pAGE107 (Miyaji H et al. 1990), pAGE103 (Mizukami T et al. 1987), pHSG274 (Brady G et al. 1984), pKCR (O'Hare K et al. 1981), pSGl beta d2-4-(Miyaji H et al. 1990) and the like. Other examples of plasmids include replicating plasmids comprising an origin of replication, or integrative plasmids, such as for instance pUC, pcDNA, pBR, and the like. Other examples of viral vector include adenoviral, retroviral, herpes virus and AAV vectors. Such recombinant viruses may be produced by techniques known in the art, such as by transfecting packaging cells or by transient transfection with helper plasmids or viruses. Typical examples of virus packaging cells include PA317 cells, PsiCRIP cells, GPenv+ cells, 293 cells, etc. Detailed protocols for producing such replication-defective recombinant viruses may be found for instance in WO 95/14785, WO 96/22378, US 5,882,877, US 6,013,516, US 4,861,719, US 5,278,056 and WO 94/19478.

A further aspect of the invention relates to a host cell which has been transfected, infected or transformed by a nucleic acid and/or a vector according to the invention.

The term "transformation" means the introduction of a "foreign" (i.e. extrinsic or extracellular) gene, DNA or RNA sequence to a host cell, so that the host cell will express the introduced gene or sequence to produce a desired substance, typically a protein or enzyme coded by the introduced gene or sequence. A host cell that receives and expresses introduced DNA or RNA has been "transformed" .

The nucleic acids of the invention may be used to produce a fusion protein of the present invention in a suitable expression system. The term "expression system" means a host cell and compatible vector under suitable conditions, e.g. for the expression of a protein coded for by foreign DNA carried by the vector and introduced to the host cell. Common expression systems include E. coli host cells and plasmid vectors, insect host cells and Baculovirus vectors, and mammalian host cells and vectors. Other examples of host cells include, without limitation, prokaryotic cells (such as bacteria) and eukaryotic cells (such as yeast cells, mammalian cells, insect cells, plant cells, etc.). Specific examples include E.coli, Kluyveromyces or Saccharomyces yeasts, mammalian cell lines (e.g., Vero cells, CHO cells, 3T3 cells, COS cells, etc.) as well as primary or established mammalian cell cultures (e.g., produced from lymphoblasts, fibroblasts, embryonic cells, epithelial cells, nervous cells, adipocytes, etc.). Examples also include mouse SP2/0-Agl4 cell (ATCC CRL1581), mouse P3X63-Ag8.653 cell (ATCC CRL1580), CHO cell in which a dihydrofolate reductase gene (hereinafter referred to as "DHFR gene") is defective (Urlaub G et al; 1980), rat YB2/3HL.P2.G11.16Ag.2O cell (ATCC CRL1662, hereinafter referred to as "YB2/0 cell"), and the like. The present invention also relates to a method of producing a recombinant host cell expressing an antibody according to the invention, said method comprising the steps of: (i) introducing in vitro or ex vivo a recombinant nucleic acid or a vector as described above into a competent host cell, (ii) culturing in vitro or ex vivo the recombinant host cell obtained and (iii), optionally, selecting the cells which express and/or secrete said antibody. Such recombinant host cells can be used for the production of antibodies of the present invention.

Fusion protein of the present invention is suitably separated from the culture medium by conventional immunoglobulin purification procedures such as, for example, protein A- Sepharose, hydroxylapatite chromatography, gel electrophoresis, dialysis, or affinity chromatography.

Pharmaceutical compositions

Typically, the fusion protein of the present invention is administered to the subject in the form of a pharmaceutical composition which comprises a pharmaceutically acceptable carrier.

Thus, the invention also relates to a pharmaceutical composition comprising a fusion protein of the invention for use in the treatment of a PTCL in a subject in need thereof.

Pharmaceutically acceptable carriers that may be used in these compositions include, but are not limited to, ion exchangers, alumina, aluminum stearate, lecithin, serum proteins, such as human serum albumin, buffer substances such as phosphates, glycine, sorbic acid, potassium sorbate, partial glyceride mixtures of saturated vegetable fatty acids, water, salts or electrolytes, such as protamine sulfate, disodium hydrogen phosphate, potassium hydrogen phosphate, sodium chloride, zinc salts, colloidal silica, magnesium trisilicate, polyvinyl pyrrolidone, cellulose-based substances, polyethylene glycol, sodium carboxymethylcellulose, polyacrylates, waxes, polyethylene-polyoxypropylene- block polymers, polyethylene glycol and wool fat. For use in administration to a patient, the composition will be formulated for administration to the patient. The compositions of the present invention may be administered orally, parenterally, by inhalation spray, topically, rectally, nasally, buccally, vaginally or via an implanted reservoir. The used herein includes subcutaneous, intravenous, intramuscular, intra-articular, intra-synovial, intrastemal, intrathecal, intrahepatic, intralesional and intracranial injection or infusion techniques. Sterile injectable forms of the compositions of this invention may be aqueous or an oleaginous suspension. These suspensions may be formulated according to techniques known in the art using suitable dispersing or wetting agents and suspending agents. The sterile injectable preparation may also be a sterile injectable solution or suspension in a non-toxic parenterally acceptable diluent or solvent, for example as a solution in 1,3-butanediol. Among the acceptable vehicles and solvents that may be employed are water, Ringer's solution and isotonic sodium chloride solution. In addition, sterile, fixed oils are conventionally employed as a solvent or suspending medium. For this purpose, any bland fixed oil may be employed including synthetic mono-or diglycerides. Fatty acids, such as oleic acid and its glyceride derivatives are useful in the preparation of injectables, as are natural pharmaceutically acceptable oils, such as olive oil or castor oil, especially in their polyoxyethylated versions. These oil solutions or suspensions may also contain a long-chain alcohol diluent or dispersant, such as carboxymethyl cellulose or similar dispersing agents that are commonly used in the formulation of pharmaceutically acceptable dosage forms including emulsions and suspensions. Other commonly used surfactants, such as Tweens, Spans and other emulsifying agents or bioavailability enhancers which are commonly used in the manufacture of pharmaceutically acceptable solid, liquid, or other dosage forms may also be used for the purposes of formulation. The compositions of this invention may be orally administered in any orally acceptable dosage form including, but not limited to, capsules, tablets, aqueous suspensions or solutions. In the case of tablets for oral use, carriers commonly used include lactose and com starch. Lubricating agents, such as magnesium stearate, are also typically added. For oral administration in a capsule form, useful diluents include, e.g., lactose. When aqueous suspensions are required for oral use, the active ingredient is combined with emulsifying and suspending agents. If desired, certain sweetening, flavoring or coloring agents may also be added. Alternatively, the compositions of this invention may be administered in the form of suppositories for rectal administration. These can be prepared by mixing the agent with a suitable non-irritating excipient that is solid at room temperature but liquid at rectal temperature and therefore will melt in the rectum to release the drug. Such materials include cocoa butter, beeswax and polyethylene glycols. The compositions of this invention may also be administered topically, especially when the target of treatment includes areas or organs readily accessible by topical application, including diseases of the eye, the skin, or the lower intestinal tract. Suitable topical formulations are readily prepared for each of these areas or organs. For topical applications, the compositions may be formulated in a suitable ointment containing the active component suspended or dissolved in one or more carriers. Carriers for topical administration of the compounds of this invention include, but are not limited to, mineral oil, liquid petrolatum, white petrolatum, propylene glycol, polyoxyethylene, polyoxypropylene compound, emulsifying wax and water. Alternatively, the compositions can be formulated in a suitable lotion or cream containing the active components suspended or dissolved in one or more pharmaceutically acceptable carriers. Suitable carriers include, but are not limited to, mineral oil, sorbitan monostearate, polysorbate 60, cetyl esters wax, cetearyl alcohol, 2- octyldodecanol, benzyl alcohol and water. Topical application for the lower intestinal tract can be effected in a rectal suppository formulation (see above) or in a suitable enema formulation. Patches may also be used. The compositions of this invention may also be administered by nasal aerosol or inhalation. Such compositions are prepared according to techniques well- known in the art of pharmaceutical formulation and may be prepared as solutions in saline, employing benzyl alcohol or other suitable preservatives, absorption promoters to enhance bioavailability, fluorocarbons, and/or other conventional solubilizing or dispersing agents. For example, an antibody present in a pharmaceutical composition of this invention can be supplied at a concentration of 10 mg/mL in either 100 mg (10 mL) or 500 mg (50 mL) single-use vials. The product is formulated for IV administration in 9.0 mg/mL sodium chloride, 7.35 mg/mL sodium citrate dihydrate, 0.7 mg/mL polysorbate 80, and Sterile Water for Injection. The pH is adjusted to 6.5. An exemplary suitable dosage range for an antibody in a pharmaceutical composition of this invention may between about 1 mg/m2 and 500 mg/m2. However, it will be appreciated that these schedules are exemplary and that an optimal schedule and regimen can be adapted taking into account the affinity and tolerability of the particular antibody in the pharmaceutical composition that must be determined in clinical trials. A pharmaceutical composition of the invention for injection (e.g., intramuscular, i.v.) could be prepared to contain sterile buffered water (e.g. 1 ml for intramuscular), and between about 1 ng to about 100 mg, e.g. about 50 ng to about 30 mg or more preferably, about 5 mg to about 25 mg, of an antimyosin 18 A antibody of the invention.

In certain embodiments, the use of liposomes and/or nanoparticles is contemplated for the introduction of the fusion protein into host cells. The formation and use of liposomes and/or nanoparticles are known to those of skill in the art.

Nanocapsules can generally entrap compounds in a stable and reproducible way. To avoid side effects due to intracellular polymeric overloading, such ultrafine particles (sized around 0.1 pm) are generally designed using polymers able to be degraded in vivo. Biodegradable polyalkyl-cyanoacrylate nanoparticles that meet these requirements are contemplated for use in the present invention, and such particles may be are easily made. Liposomes are formed from phospholipids that are dispersed in an aqueous medium and spontaneously form multilamellar concentric bilayer vesicles (also termed multilamellar vesicles (MLVs)). MLVs generally have diameters of from 25 nm to 4 pm. Sonication of MLVs results in the formation of small unilamellar vesicles (SUVs) with diameters in the range of 200 to 500 A, containing an aqueous solution in the core. The physical characteristics of liposomes depend on pH, ionic strength and the presence of divalent cations.

The invention will be further illustrated by the following figures and examples. However, these examples and figures should not be interpreted in any way as limiting the scope of the present invention.

FIGURES:

Figure 1: (A) Flow cytometry (CMF) results of ICOSL expression using anti-ICOSL clone MIH12 and an LSR Fortessa X20 (BD Biosciences) in SS patients, compared to healthy donors (HD). Mean fluorescence intensity (MFI) is significantly higher in SS patients (662 versus 250, p=0.0057, Mann-Whitney test). The positivity threshold using CMF can thus be considered at 500 under these technical conditions, i.e. twice the median of ICOSL expression in healthy donors, in which the MFI of COSL varied from 100 to 400. (B) Western blot analyzes of PBMC from healthy (HD) and patient (SS) donors showing ICOSL long isoforms in 4/5 SS samples.

Figure 2: Expression of ICOSL isoform 4.1 and/or 4.2 in SS cell lines & monocytes. A total mRNA extraction was done. RT-PCR primers are specific to the intracellular part of the long ICOSL isoform (280 bp for the long ICOSL isoform 4.1 intracellular part and 400 bp for the long ICOSL isoform 4.2 intracellular part).

Figure 3: Immunoprecipitation of 33, 55 and 60kDa ICOSL isoform with the 2D3 anti- ICOSL m!gG2b from SEAX cell lysate. Western blot was performed using rabbit polyclonal anti-ICOSL (ab!24972).

Figure 4: ICOSL expression on cell sorted SS tumor cells from 2 patients. Purified CD3+ CD4+ CD158k+ cell sorted tumor cells were harvested and treated to extract protein and mRNA.

Figure 5: Targeting of ICOSL: rICOS-Fc & ADCC-like efficient on cell lines. (A) HUT78 cells. (B) Seax cells. Figure 6: ICOS-Fc induced cytolysis evaluated by means on SEAX and HUT78 cell lines stained with CFSE and using PBMC as effectors at various efector/target ratios. An anti- CD25 (IgGl) was used as positive control. 1

Table 1: ICOS-L is expressed by neoplastic Sezary cells and other PTCL tumor cell lines

ALL: acute lymphoblastic leukemia; HSTL: hepatosplenic T-cell lymphoma; ENKTCL: Extranodal NK/T-cell lymphoma; ALCL: anaplastic large cell lymphoma.

EXAMPLES:

Example 1: Expression of ICOS and ICOSL on the surface of tumor cells of PTCL and of ICOSL in serum

Material & Methods In vitro study of ICOSL: In vitro study of ICOSL in blood mononuclear cells (PBMCs) from SS patients (Sezary cells [SC] n=13), healthy donors (HD, n=10) and SS cell lines.

Different studies have been done to study the expression of ICOSL:

1/ expression by flow cytometry (CMF) (CD3+/KIR3DL2+ tumor populations for SC), after stimulation for PBMCs of HD (CD3/CD28 beads);

2/ RT-PCR with sequencing (Sanger) and westemblot/immunoprecipitation (WB/IP) in SC. RT-PCR were done with specific primers targeting the intracellular part of ICOS-L (Forward primer: cagagagacgagtgctagacccc; Reverse primer: ctatgttgctcctggaac). 95°C 30sec, 60°C 15 sec, 72°C Imin. 40 cycles.

Cells lysates were obtained with NP40 1% cell lysate buffer for 1H at 4°C, and after centrifugation at 10000 rpm 15min at 4°C. Cell lysates were directly loaded on 8% acrylamide (SDS-PAGE) gels or subjected to immunoprecipitations with anti ICOS-L 2D3 antibody. The immunoprecipitates where then loaded on 8% SDS PAGE gels.

Immunoblots were realized with the anti-ICOSL MAB165-100 (clone 136726) from RD Systems.

In vitro cytotoxicity tests (ADCC-like):

These tests have been done on heterologous CTCL lines with HD PBMCs as effectors with an ICOS-Fc construct. Briefly, target cells (HUT78 or Seax) were stained with CFSE before co-cultured at different ratios (1-1, 5-1, 10-1) with effector cells (PBMC from healthy donors) and either human IgGl control or ICOS-FC both at lug/ml for 16 hours. Cell apoptosis was measured by flow cytometry, using a viability dye (VD efluor780). The % of ADCC was calculated as followed: % of CFSE ⁺ VD ⁺ / ((% of CFSE ⁺ VD ⁺ / % of (CFSE ⁺ VD ⁺ + CFSE ⁺ VD’))*100

The ICOS-Fc sequence used for these experiments correspond to the extracellular part of ICOS (in bolt) fused to a linker (italic) and the human IgGl sequence from Prohn 100 to Lysin 330.

Results

ICOSL expression in Sezary syndrome (SS):

Flow cytometry (CMF) data show that the majority of PTCL/CTCL cell lines studied express ICOSL, assessed with clone 2D3. The expression levels vary according to the lines but are high for the majority of CTCL lines (average MFI of 861 (minimum 234 - maximum 15744)) with clone 2D3 (data not shown). ICOSL is also expressed on primary CTCL cells, particularly in Sezary syndrome (Figure 1A), at lower levels than on cell lines, however. In normal T cells, we did not identify ICOSL expression, either in the basal state or after CD3/CD28 stimulation, with MFIs always below 400 using the MIH12 clone. The presence of ICOSL in SS tumor cells is confirmed by Western Blot studies, as illustrated in appendix 01 (figure IB, Figure 3). We find ICOSL on the surface of primary cells of patients with PTCL apart from Sezary syndrome, in particular in tumor cells of angioimmunoblastic T-cell lymphoma and in primary cells of patients with hepato-splenic T-cell lymphoma (HSTL) (data not shown). The expression of IOSL in the HSTLs is in agreement with its identification in the lines studied previously: DERL2 and DERL7. These results indicate that the tumor cells of most PTCLs express ICOSL, knowing that in many cases there is co-expression of its receptor (ICOS) on the surface of the tumor cells. An MFI of 400 using the clone MIH12 can be considered as a threshold value to define the positivity of a sample in flow cytometry, with an LSR Fortessa X20 device (BD Biosciences). ICOSL is expressed in S, AITL and HSTL, and its identification in many lines suggests that it could also be expressed in vivo by many other subtypes, including transformed mycosis fungoides (MyLa+ line) , analasic T-cell lymphomas (SUHL1+ line), lymphoblastic T-cell lymphomas (MOLT4+ line) and nasal-type NK T-cell lymphomas (SNK6 and YT + lines).

ICOSL isoforms:

We observed different expression profiles depending on the anti-ICOSL clone used in CMF.

RT-PCR analysis identifies, alone or in combination with the "classical" isoform 2 (1112bp), the 4.1 isoform of ICOSL (2025bp for the total size of the isoform) in SS lines and monocytes from healthy donors, including an additional 120 bp subvariant 4 in the intracellular part which we called isoform 4.2 (see the figure 2). Sequencing of this part of ICOSL isoform 4 (MyLa, H9 and SeAx lines and monocytes) shows that this long form carries an additional proline-rich domain compared to variant 4 (variant 4.2) (data not shown).

As in PBMCs from patients with SS, ICOSL immunoprecipitation reveals proteins of different sizes in the lines studied (in particular MyLa, HUT78 and SeAx, Table 1, Figure 4), with, in some samples, several isoforms present (35, 50kDa and 60-70kDa). Based on the sizes of the proteins obtained, we can assume that the two heaviest proteins are the 4.2 and 4.1 isoforms. The last form at 35 kDa corresponds to the widely described “classical” ICOSL (isoform 2). In agreement with the RT-PCR data, these data confirm the expression of different ICOSL isoforms, without it being possible to clearly conclude on the more precise specificity of the anti-ICOSL antibodies used in CMF.

More, ICOS-L is expressed in other PTCL tumor cell lines (Table 1) and we identified ICOSL in primary cells from a patient with an hepatosplenic T-cell lymphoma and in tumor cells from two patient derived xenografted (PDX) mice of angioimmunoblastic T-cell lymphomas (AITL).

ICOS/ICOSL pathway in the model of Sezary syndrome:

Concerning the Sezary cells (SCs), the engagement of ICOS does not induce their proliferation in vitro, contrary to what is observed with T lymphocytes from healthy donors, which are activated ICOS alone, or associated with CD3 or CD3/CD28. The blocking of ICOS/ICOSL on the SCs leads to increased mortality after 48 hours (18% to 27%) of culture in complete medium. This effect is much less in the presence of IL-2 which promotes cell survival.

Concerning the SS (Sezary Syndrome) line, SeAx, which strongly co-expresses ICOS and its ligand, we observed that blocking ICOS has a positive impact on cell mortality, as we observed in primary cells. However, the use of blocking anti-ICOSL antibodies does not lead to the same result. This may be due to a different conformation of the ICOSL-4 isoforms.

The use of proteome kits shows that the blocking of ICOS on the SeAx cell line, leads to a reduction in the levels of phosphorylation of Akt and of WNK1, target of Akt. There was also a reduction in the phosphorylation of AMPal, upstream of Akt in the see PI3K/Akt. We also observe a reduction in the levels of phosphorylation of p53, PRAS40 and GSK3/beta. Furthermore, we observe an increase in the level of phosphorylation of HSP27 and c-Jun. Concerning the apoptosis effectors, we observe a clear increase in the phosphorylation of cleaved caspase 3 and the phosphorylation of HSP27. These results confirm that ICOS blockade increases apoptosis in the SeAx line and more generally in SCs.

Targeting of SS tumor cells by ICOS-Fc:

The targeting of CS with the ICOS-Fc strategy could be effective and overcomes the potential problems of recognition of the isoforms expressed, which vary greatly from one sample to another. The preliminary tests that we carried out in vitro by using a a fusion protein ICOS-Fc according to the invention. The results obtained by ADCC tests in vitro on lines, using effectors from healthy donors, show a significant mortality increase in target cells compared to the control isotype (HUT78 and SeAx lines, SS models) (Figure 5 and 6). REFERENCES:

Throughout this application, various references describe the state of the art to which this invention pertains. The disclosures of these references are hereby incorporated by reference into the present disclosure.

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