The present invention relates to a combination therapy which comprises a tumour selective toxic virus and one or more therapeutic agents that reduce tumour blood vessel formation or damage tumour vasculature, especially for use in the treatment of neoplasms including solid tumours, metastases and other vascularised lesions.

The therapeutic agent or agents may have additional antitumour effects, for example, as inhibitors of tumour cell proliferation via a cell cycle specific effect or via signal transduction inhibition. The invention also relates to a method of treating neoplasms such as tumours, particularly solid tumours, metastases and other vascularised lesions with such a combination and the use of such combinations in therapy for cancer.

Tumour selective toxic viruses, particularly those known as oncolytic viruses, are viruses that have either been naturally selected or engineered to replicate selectively in tumour cells as compared to other cells and thus lead to tumour cell death. In general, these tumour toxic viruses derive their specificity by exploiting cell surface or intracellular aberrations in gene expression that arise during tumour evolution. Such viruses have great potential in therapy for cancer as they can spread progressively through a tumour until all of its cells are destroyed. Most current targeting strategies used to achieve tumour selective replication exploit tumour- specific defects in the regulation of cellular DNA replication or transcription. Using a replicating virus overcomes the need to infect all tumour cells at the time the virus is injected, which is a major limitation to conventional replacement gene therapy, because in principle virus goes on being produced, lysing cells on release of new virus, until no rumour cells remain.

The strength of this approach is that the therapeutic effect of the injected virus is augmented by that of virus produced within the tumour. Since the acute side effects of virus treatment are directly related to the amount of virus injected, the ability to inject a smaller amount of virus is an important advantage of replicating viruses.

However, there remains a need to further improve the efficacy of viral therapy for cancers, particularly when treating fast growing tumours.

The anti-tumour activity of several oncolytic viruses in combination with particular classes of therapeutic drugs has previously been examined. An oncolytic

adenovirus targeted to PSA positive prostate cells, termed CV787, resulted in synergistic cytotoxic effects when applied in combination with taxane antimicrotubule agents, paclitaxel and docetaxel, both in vitro and in vivo, see Yu et al. Cancer Res., 61: 517-525, 2001.

Another combination previously reported was ONYX-015, an adenovirus that replicates in and lyses tumour cells with defects in the p53 pathway, used in combination with 5-FU and cisplatin. No difference in viral titer could be found compared with cells treated with ONYX-015 alone, see Heise, C et al. Clinical Cancer Research Vol. 6, 4908-4914, December 2000.

The present inventors believe that some of the prior art therapeutic agents, for example, 5-FU and cisplatin, are actually toxic to the replicating virus and thus not ideal for use in combination therapy. 5-FU is an inhibitor of thymidylate synthase that inhibits cellular DNA synthesis by inhibiting nucleotide synthesis. Viral replication is dependent upon the cell's supply of nucleotides, thus replication of viral DNA will also be impaired. Cisplatin is a DNA damaging agent that will damage viral DNA as well as cellular DNA. Thus there is a need for alternative and improved oncolytic and therapeutic agent combinations for use in therapy.

Mullen et al, Cancer; VoI 101, pp869-877 (2004) describe use of an oncolytic Herpes simplex virus (HSV-I) vector that expresses endostatin in mice in vivo. This was seen to provide inhibition of angiogenesis around the cells from which the expression occurs together with direct tumour cell destruction. Tumours became soft and centrally necrotic with some tumours completely sloughed. However, new tumours regrow by 7 to 10 days later. HSV-I replication in tumours was not detectable after 1 week from administration.

Wong et al, Clin. Cancer. Res VoI 10, 4509-4516 (2004) describes an oncolytic herpes virus that expresses Interleukin 12 (IL 12), a proinflammatory and antiangiogenic cytokine which recruits immune cells to the site of oncolysis. Test tumour volumes rose over 13 days to over 500mm as compared to the control virus 1500mm ³ .

EP 1347042 discloses adenoviruses expressing angiogenesis inhibitors endostatin and angiostatin. Such virus proved effective in control of subcutaneously injected lymphomas. WO2002/088173 discloses similar adenoviruses. WO03/088567 discloses expression of tumour angiogenesis inhibitory factor-no data is presented.

The present inventors have now determined that the combination of a tumour selective toxic virus and an independent therapeutic agent that reduces blood vessel formation or damages tumour blood vessels is surprisingly effective at reducing tumour mass or even eradicating tumours.

Preferred viruses are self replicating, ie. replication competent, often referred to as an oncolytic virus.

The present inventors have also determined that a single therapeutic agent that, in addition to acting on the tumour vasculature, also inhibits tumour cell proliferation, is particularly advantageous when used in combination with an oncotoxic virus. A single therapeutic agent that acts as an immunosuppresant, anti- angiogenic and anti-proliferative is particularly suitable for use in the present combination. Alternatively, several agents may be used in combination with the virus to provide these different therapeutic effects.

The efficiency by which an oncolytic virus can kill a tumour is influenced by a number of factors including the amount virus that reaches and infects the tumour cells and also the speed at which the virus can spread from cell to cell through the tumour. Following administration of the virus, infection and lysis of tumour cells in often confined to localised areas, or foci, within the tumour mass. The virus then spreads out from these foci by replication and subsequent lysis of the neighbouring tumour cells. Upon lysis, the virus is released from the tumour cell and thus spreads to adjacent tumour cells and infects those. If the tumour is particularly fast growing, new tumour cells are formed at a rate that is faster than the rate of spread of the virus through the tumour. In effect, the growth of the tumour outpaces the spread of viral infection and the tumour escapes from the virus.

The inventors have shown that the administration of a combination of an oncolytic virus and a therapeutic agent that acts on the tumour vasculature is particularly efficacious in killing tumour cells. There are a number of reasons for this.

Firstly, reducing or shutting down the blood supply to the tumour by using an angiogenesis inhibitor and/or vascular targeting agent limits the availability of nutrients and oxygen, and thus slows tumour growth enabling the spread of the virus within the tumour to catch up with tumour cell division.

Secondly, targeting the blood vessels and shutting these down, provides a physical barrier, trapping the virus within the tumour and preventing the loss of viral particles into the general circulation.

Thirdly, the therapeutic agents used as angiogenesis inhibitors or vascular targeting agents generally have minimal or no toxicity to the virus. In the present invention this is particulary enhanced by using such agents that have, unlike the prior art, a more general anti-proliferative effect in addition to vascular growth inhibition.

Accordingly, in a first aspect the invention provides a method of therapy for a neoplasm in a patient comprising administering to the patient a combination of (i) a tumour selective toxic virus, and (ii) a independent therapeutic drug, wherein the therapeutic drug reduces tumour blood vessel formation or damages tumour blood vessels and is selected preferably selected from the group consisting of Vascular Targeting Agents (VTAs), mTOR inhibitors and Histone Deacetylase (HDAC) inhibitors.

In a second aspect the invention provides a combination for therapy of a neoplasm in a patient, the combination comprising (i) a tumour selective toxic virus, and (ii) a independent therapeutic drug, wherein the therapeutic drug reduces tumour blood vessel formation or damages tumour blood vessels and is preferably selected from the group consisting of Vascular Targeting Agents (VTAs), mTOR inhibitors and Histone Deacetylase (HDAC) inhibitors for simultaneous, concurrent, separate or sequential use.

In a third aspect the invention provides the use of a therapeutic agent that reduces blood vessel formation or damages tumour blood vessels, preferably selected from the group consisting of Vascular Targeting Agents (VTAs), mTOR inhibitors and Histone Deacetylase (HDAC) inhibitors, for the preparation of a medicament, for use in combination with an oncotoxic virus, for the therapy of a neoplasm in a patient.

In a fourth aspect the invention provides the use of an oncotoxic virus, for the preparation of a medicament, for use in combination with a therapeutic agent that reduces blood vessel formation or damages tumour blood vessels, preferably selected from the group consisting of Vascular Targeting Agents (VTAs), mTOR inhibitors and Histone Deacetylase (HDAC) inhibitors , for the therapy of a neoplasm in a patient.

The term independent as used above means not expressed from the virus.

Preferred embodiments of the first, second, third and fourth aspects of the present invention are those wherein the therapeutic drug is selected from the group consisting of mTOR inhibitors and Histone Deacetylase (HDAC) inhibitors as these are antiproliferatives and are seen to be surprisising effective

A tumor selective virus is herein a virus that is more toxic to a tumour cell than to other cells of a patient. Preferably the virus is an oncolytic virus and more preferably one that is self-replicating (replication competent), i.e. that can replicate in a tumour cell.

A particular further difference between the present invention and that of the prior art anti-angiogenic peptide expressing viruses is the independent nature of the components of the combination. Thus, preferably the components are administered separately, with the virus being preferably administered to the tumour and, in preferred therapies, the drug being administered at a later time and optionally pregferably to the body as a whole, eg. systemic administration, by mouth or parenterally.

Particularly the drug is administered 4 or more hours after the virus, preferably 1 to 5 days after the virus. In the event that the virus is to be administered on more than one occasion in a particular regimen, the administration of the drug is stopped for up to 3 days before that readministration of virus, preferably for 1 day, and then the administration of drug is resumed at 4 hours to 5 days thereafter, preferably within 1 day.

The preferred virus and drug combinations of the invention result in significant amounts of virus remaining in tumour cells after 5 weeks as determined by FISH staining for DNA. This is beyond that seen in the viruses expressing anti- angiogenic peptides of the prior art (eg 7 days) and may be indicative of the ability of separately administered drug to maximise viral infectivity and replication whilst slowing down the growth of the tumour to that which allows more effective viral spread.

Combinations maybe provided as kits with doses of virus and doses of drug.

Diseases to be treated

The combinations of the present invention are useful for treating neoplasms such as tumours and/or any metastases. The combinations are particularly useful in treating vascularised solid tumours and/or metastases including tumours derived from

colon cells, more particularly liver tumours that are metastases of colon cell primary tumours. Neoplasms that are not traditionally classified as solid tumours, but that nevertheless involve a degree of vascularisation, may also be suitable for treatment with the combination, e.g. multiple myeloma.

Other tumours and/or metastases that may be treated of the invention include breast cancer, ovarian cancer, head and neck cancer, lung cancer, prostate cancer and stomach cancer. Tumours that may be treated using the combination and method of the invention include tumours with mutations in APC gene or β-catenin pathway. Such defects are almost universal in colon cancer but they also occur at lower frequency in other tumours, such as melanoma, hepatocellular carcinoma and ovarian cancer. Such mutations lead to increased Tcf activity in affected cells. Thus an oncolytic virus comprising one or more Tcf regulated promoters is particular useful for the treatment of neoplasms of the colon, ovary and liver (hepatocellular carcinoma).

Tumours of the liver are particularly amenable to treatment using the method and combination of the invention because the oncotoxic virus can be administered via the hepatic artery, permitting relatively large doses of oncotoxic virus to reach the liver.

Secondary rumours are one of the most common causes of death in cancer patients and are by far and away the most common form of liver tumour. Although virtually any malignancy can metastasise to the liver, tumours which are most likely to spread to the liver include: cancer of the stomach, colon, and pancreas; melanoma; tumours of the lung, oropharynx, and bladder; Hodgkin's and non-Hodgkin's lymphoma and tumours of the breast, ovary, prostate and eye.

Viruses for use in the combination

The term tumor selective toxic virus is a broad one as there are many different viruses that are designed to, or have been selected to, replicate in and kill a wide range of different tumour types. The inventors have particularly found that combining an oncolytic virus with a therapeutic agent that acts on the tumour vasculature can result in improved therapies for the treatment of neoplasms. The term "toxic virus" as used herein relates to any virus that replicates preferentially, e.g. exclusively or at an elevated level in tumour cell as compared to other cells.

Toxic viruses include replication competent, and particularly replication efficient, adenovirus constructs that selectively replicate in response to transcription activators present in tumour cells, these factors being present either exclusively or at elevated levels in tumour cells as compared to other cells, and thus which lead to tumour cell death and cell lysis. To achieve tumour preferential replication the promoters of one or more viral genes are substituted or modified by the addition of regulatory sequences that are preferentially activated in cancer cells.

Toxic viruses that may be particularly useful in the inventive combination include those described in WO 00/56909 (BTG International Limited.) and WO 03/006662 (BTG International Limited.) incorporated herein by reference, particularly adenoviruses that have Tcf driven promoters and thus replicate preferentially in cells with mutations in wnt signalling pathway such as colon cancer cells. Other preferred adenoviruses are equivalent viruses with HRE promoters. Particualry preferred such viruses are those with wild type E2 promoters but tumour specific ElA and/or ElB promoters having the packaging signal relocated to the right hand side of the viral genome. Preferred tumour specific sites are HRE and Tcf sites, placed into the inverted terminal repeats (to drive ElA and to a lesser extent E4). Preferred viruses include an integrin targeting peptide (CDCRGDCFC), preferably in the fiber gene.

To produce a tightly regulated tumour specific transcription factor driven virus, a mutant ElA promoter, such as a Tcf-EIA promoter, needs to be installed. To effect this the present inventors have substituted part of the left hand inverted terminal repeat (ITR) of the virus with tumour specific promoter, eg Tcf binding sites. More preferably the El A enhancer is deleted from its wild type location, in part or in full, more preferably completely. Most preferably the packaging signal is relocated from its wild type site near the left hand ITR to another part of the viral genome where it is still effective to allow packaging of the virus. This is preferably relocated to adjacent the right hand ITR, more preferably to within 600bp thereof. The packaging signal may be relocated in either orientation.

The tumour transcription factor specific promoter conveniently comprises one or more Tcf binding sites, more preferably two to ten, still more preferably three to five Tcf sites in tandem. Most preferably four Tcf binding sites replace a portion of the ITR, the ElA enhancer and the packaging signal on the left hand side while the

packaging signal sequence is introduced adjacent the right hand ITR to permit proper encapsidation of viral DNA.

The right side substitutions are particularly desirable to maintain the symmetry of the terminal repeats, so a similar or identical number of tumour specific transcription factor binding sites are inserted in the right ITR as provided in the left ITR, such as to allow these sites to become base paired together during replication. It will be realised that these insertions are preferably subsitutions as with the left side changes.

Tumour specific promoter-dependent transcription, eg with Tcf sites, is inhibited by ElA, so the inventors also investigated mutations in the ElA protein that would abolish this repression in transcription assays. Mutation of the p300 binding site in El A partially relieved the repression, but in the context of the virus this mutation did not lead to increased transcription from the Tcf-E2 promoter and actually reduced the activity of the virus. Similar attenuation by mutation of the ammo-terminus of ElA has been reported by the Onyx group. In contrast, it has now been surpisingly determined that the viruses containing only the transcription factor binding site changes in the ElA and E4 promoters (see for example vCFll in the Examples herein) are selective for cells with active wnt signalling and active in most of the colon cancer cells studied.

It will be realised by those skilled in the art that any type of virus, which is potentially cytotoxic to tumour cells, may be employed in the combination of the present invention. Replication competent toxic viruses used in the invention may affect kill tumour by lysis i.e. be oncolytic or may kill tumour cells via a different mechanism. Particular examples of viruses for use in the practice of the invention include adenovirus, retrovirus, reovirus, vesicular stomatitis virus, Newcastle Disease virus, polyoma virus, vaccinia virus, herpes simplex virus and parvovirus.

Preferably the toxic virus is an adenovirus, more preferably an adenovirus that is of high specificity for a target tumour cell type, e.g. for a colon tumour type. Preferred colon tumour specific adenoviruses are encoded by viral DNA constructs corresponding to the DNA sequence of Ad5.

Tumour selective toxic viruses whose replication is targeted to, or increased in response to, hypoxic conditions may be particularly useful in the inventive combination because most solid tumours usually present large areas of hypoxic tissue. The therapeutic agent used in the inventive combination, because it acts on the

tumour vasculature, is likely to increase hypoxia and thus may increase replication of a hypoxia responsive virus. Hypoxia responsive viruses include viruses whose replication is dependent upon or increased in the presence of HIF (Hypoxia-Inducible Factor). For example, a toxic virus comprising one or more of the regulatory sequences known as hypoxia response elements (HRE) such as the HREs described in Cancer Research 63, 6877-6884, October 15, 2003; Staller P et al., Nature. 2003 Sep 18;425(6955):307-ll; and Semenza G et al., J Biol Chem. 1996 Dec 20;271(51):32529-37.

Viruses for use in the inventive combination include viruses that have modifications to the fibre proteins, with the aim of improving the efficiency of infection of target cells at the level of receptor binding. For example, the normal cellular receptor for adenovirus, CAR, is poorly expressed on some colon tumour cells. Addition of a number of lysine residues, e.g. 1 to 25, more preferably about 5 to 20, to the end of the adeno fibre protein (the natural CAR ligand) allows the virus to use heparin sulphate glycoproteins as receptor, resulting in more efficient infection of a much wider range of cells. Fibre mutations that introduce NGR, PRP or RGD peptides may also be exploited, either increasing or decreasing such effect depending upon the need to increase or decrease infectivity toward given cell types. Modification of the C terminus of the adenoviral fibre protein by the addition of an RGD-containing peptide is useful in the practice of the invention. For example the Tcf regulated adenovirus vKH6, described in the examples herein, has an RGD peptide incorporated in its fibre protein and retains its CAR binding ability permitting it to infect a broad range of tumour cells.

To produce a tightly regulated tumour specific transcription factor driven virus, a mutant ElA promoter, such as a Tcf-El A promoter, needs to be installed. To effect this the present inventors have substituted part of the left hand inverted terminal repeat (ITR) of the virus with tumour specific promoter, eg Tcf binding sites. More preferably the El A enhancer is deleted from its wild type location, in part or in full, more preferably completely. Most preferably the packaging signal is relocated from its wild type site near the the left hand ITR to another part of the viral genome where it is still effective to allow packaging of the virus. This is preferably relocated to adjacent the right hand ITR, more preferably to within 600bp thereof. The packaging signal may be relocated in either orientation.

The tumour transcription factor specific promoter conveniently comprises one or more Tcf binding sites, more preferably two to ten, still more preferably three to five Tcf sites in tandem. Most preferably four Tcf binding sites replace a portion of the ITR, the ElA enhancer and the packaging signal on the left hand side while the packaging signal sequence is introduced adjacent the right hand ITR to permit proper encapsidation of viral DNA.

The right side substitutions are particularly desirable to maintain the symmetry of the terminal repeats, so a similar or identical number of tumour specific transcription factor binding sites are inserted in the right ITR as provided in the left ITR, such as to allow these sites to become base paired together during replication. It will be realised that these insertions are preferably subsitutions as with the left side changes.

Tumour specific promoter-dependent transcription, eg with Tcf sites, is inhibited by ElA, so the inventors also investigated mutations in the ElA protein that would abolish this repression in transcription assays. Mutation of the p300 binding site in El A partially relieved the repression, but in the context of the virus this mutation did not lead to increased transcription from the Tcf-E2 promoter and actually reduced the activity of the virus. Similar attenuation by mutation of the amino-terminus of ElA has been reported by the Onyx group. In contrast, it has now been surpisingly determined that the viruses containing only the transcription factor binding site changes in the ElA and E4 promoters (see for example vCFl l in the Examples herein) are selective for cells with active wnt signalling and active in most of the colon cancer cells studied.

Therapeutic agents for use in the combination

There are a number of different classes of agent that may be used in the combination. Agents to be used in the invention are those that act as angiogenesis inhibitors or damage the tumour vasculature to reduce perfusion of the tumour e.g. vascular targeting agents. These are not limited to agents that are conventionally classified as angiogenesis inhibitors or vascular targeting agents but also include agents that have an anti-angiogenic effect or damage the tumour vasculature. In addition to having an effect on the tumour vasculature, the agents used in the inventive combination preferably have minimal or no toxicity to the toxic virus so that its ability to replicate and cause tumour cell death and lysis is maintained.

Therapeutic agents for use in the inventive combinations include:

1. Vascular targeting agents (VTAs)

VTAs can be broadly divided into two types, small molecule VTAs and ligand directed VTAs. Small molecule VTAs do no localise selectively to tumour blood vessels but exploit pathophysiological differences between tumour and normal endothelium to selectively occlude tumour vessels. The differences between tumour and normal endothelial cells include increased proliferation, permeability and reliance on a tubulin cytoskeleton to maintain shape, hi contrast, ligand directed VTAs use a targeting ligand to achieve selectivity of binding to and occlusion of tumour vessels. However, both types of VTAs have been reported to shut down, e.g. cause vascular collapse, or reduce blood flow through the tumour vasculature resulting in tumour cell death.

Some specific but non-limiting examples of vascular targeting agents that may be used in combination with the oncotoxic virus are listed below: Combretastatin A4 (Oxigene) Target:Endothelial tubulin. AVE8062A (Aventis) Target: Endothelial tubulin. ZD6126 (AstraZeneca) Target: Endothelial tubulin. DMXAA Target: Induction of TNF-α.

Other VTAs that may be useful in the inventive combination include those listed in Thorpe P.E. et al. Clin Cancer Res. 2004 Jan 15;10(2):415-27.

2. Angiogenesis inhibitors

Angiogenesis inhibitors are agents that prevent or reduce the formation of new tumour blood vessels. Agents that target the VEGF /VEGFR at the level of the ligand or receptor, or via downstream signalling pathways, are known to reduce angiogenesis and thus may be useful in the inventive combination. Agents that target other known anti-angiogenic targets such as Flt3, FGFs and Integrins may be useful in the inventive combination. Some specific but non-limiting examples of anti- angiogenesis inhibitors that may be used in the practice of the invention are listed below: AMG706; Thalidomide;

Avastin™ (bevacizumab) and VEGF-Trap, monoclonal antibodies that target VEGF

IMC-ICl 1 (Imclone), antibody targeting VEGFR-2;

SU5416 (Sugen/Pharmacia), receptor tyrosine kinase inhibitor targeting VEGFR-2;

SU6668 (Sugen/Pharmacia), receptor tyrosine kinase inhibitor targeting VEGFR-2, bFGFR, PDGFR;

SUl 1248 (Sugen/Pharmacia) receptor tyrosine kinase inhibitor targeting VEGFR-2,

PDGFR,c-Kit, Flt-3;

PTK787/ZK22854 (Schering/Novartis), receptor tyrosine kinase inhibitor targeting

VEGFR-I, VEGFR-2;

ZD6474 (Astra Zeneca), receptor tyrosine kinase inhibitor targeting VEGFR-2,

EGFR;

CP-547,632 (Pfizer), receptor tyrosine kinase inhibitor VEGFR-2, EGFR, PDGFR;

Inhibitors of endothelial cell proliferation including ABT-510 (Abbott), Angiostatin and Endostatin (Entremed);

Inhibitors of integrin activity including Vitaxin™ and Medi-522 (Medlmmune),

Cilengitide (Merck) targeted to αVβ3.

Preferably the angiogenesis inhibitor for use in the practice of the invention is selected from Avastin, thalidomide and PTK787.

The present invention offers advantage over the prior art use of oncolytic viruses expressing angiogenesis inhibiting proteins in so far as independent administration of the drug allows the virus to establish infectivity prior to attack on the vasculature.

3. mTOR inhibitors mTOR inhibitors are therapeutic agents that are not traditionally classed as angiogenesis inhibitors or vascular targeting agents. They are usually classified as signal transduction inhibitors or cell cycle inhibitors that act directly to inhibit tumour cell proliferation, as opposed to damaging or inhibiting growth of the tumour vasculature. mTOR, the mammalian target of rapamycin, is a downstream protein kinase of the phosphatidylinositol 3-kinase (PI3K)/Akt (protein kinase B) signalling pathway that mediates cell survival and proliferation. Thus agents that inhibit mTOR inhibit the signals required for cell cycle progression, cell growth, and proliferation, leading to tumour growth inhibition. However, in addition to their antiproliferative effects, they are known to have anti-angiogenic properties see Guba, M et al. Nat Med. 2002

Feb;8(2): 128-35. Thus niTOR inhibitors are particularly applicable for use in the practice of the invention. mTOR inhibitors also act as immuno-suppressives, a property which is particularly advantageous when they are used in combination with a toxic virus because the immune response against the virus is reduced or prevented, permitting repeat administration of virus, and may also obviate the need to use additional therapeutic agent(s) to prevent adverse reactions.

Rapamycin (sirolimus) is a highly specific inhibitor of mTOR and in fact it is the most selective protein kinase inhibitor known to date. Rapamycin and rapamycin derivatives are particularly applicable for use in combination with an oncotoxic virus, examples of such agents are those listed and referred to in WO 2004/082681 (Novartis Pharma), incorporated herein by reference.

Some specific but non-limiting examples of mTOR inhibitors that may be used in combination with an oncotoxic virus include those listed below:

Wyeth temsirohmus

Ariad AP-23841

Ariad AP-23573

Abbott ABT-578

Elan sirolimus, NanoCrystal

Isotechnika TAFA-93

Novartis RAD-OOl (everolimus)

Wyeth Sirolimus (rapamycin)

The inventors have particularly determined that the RAD-OOl (everolimus), a rapamycin derivative and mTOR inhibitor, when used in combination with an oncolytic adenovirus, produces synergistic anti-tumour effects. Thus mTOR inhibitors and particularly RAD-001 are particularly preferred agents for use in combination with a toxic virus.

Thus, in a most preferred independent aspect, the invention provides a method of therapy for a neoplasm cancer in a patient comprising administering to the patient a combination of (i) a tumour selective toxic virus, and (ii) an mTOR inhibitor.

In a further aspect the invention also provides a combination for therapy of a neoplasm in a patient, the combination comprising (i) a tumour selective toxic virus, and (ii) an mTOR inhibitor, for simultaneous, concurrent, separate or sequential use.

Preferably the mTOR inhibitor for use in combination with a tumour selective toxic virus is rapamycin, or a rapamycin derivative, more preferably RAD-001.

4. Histone Deacetylase (HDAC) Inhibitors

HDAC inhibitors are therapeutic agents that are not traditionally classed as angiogenesis inhibitors or vascular targeting agents. However, in addition to their antiproliferative and pro-apoptotic effects, they are now known to have anti- angiogenic properties, see, for example, Zgouras D et al., Biochem Biophys Res Commun. 2004 Apr 9;316(3):693-7 and Deroanne C et al., Oncogene 2002 Jan 17;21(3):427-36. The inventors believe that HDAC inhibitors are particularly applicable for use in combination with a tumour selective toxic virus.

Thus, in an independent aspect, the invention provides a method of therapy for a neoplasm cancer in a patient comprising administering to the patient a combination of (i) a tumour selective toxic virus, and (ii) a histone deacetylase inhibitor.

In a further aspect the invention also provides a combination for therapy of a neoplasm in a patient, the combination comprising (i) a tumour selective toxic virus, and (ii) a histone deacetylase inhibitor, for simultaneous, concurrent, separate or sequential use.

Preferably the histone deacetylase inhibitor for use in combination with a toxic virus is selected from SAHA, depsipeptide, LBH-589, MS275 and PXDlOl. Examples of HDAC inhibitors that may be used in the inventive combination are those listed and referred to in WO 2004/103358 (Novartis Pharma), incorporated herein by reference.

Some specific but non-limiting examples of histone deacetylase inhibitors that may be used in the practice of the invention include those listed below:

Originator Generic Name

Chipscreen Biosciences CS-00028

Chroma Therapeutics CHR-2504

Gloucester Pharmaceuticals depsipeptide (FK228)

Gloucester Pharmaceuticals FR-135313

Johnson & Johnson JNJ-16241199

Merck SAHA

Methylgene MGCD0103

Novartis LAQ-824

Novartis LBH-589

Pfizer CC 1994

Schering MS 275

Titan Pharmaceuticals pivaloyloxymethyl butyrate

TopoTarget/Curagen PXD lOl

Administration of virus

Route of administration may vary according to the patient's needs and may be by any of the routes described for viruses e.g. as those described in US 5,698,443 column 6, incorporated herein by reference. Suitable doses for oncotoxic viruses of the invention are in theory capable of being very low. For example they may be of the order of from 10 ² to 10 ¹³ , more preferably 10 ⁴ to 10 ¹¹ , with multiplicities of infection generally in the range 0.001 to 100.

For treatment a hepatic artery catheter, e.g. a port-a-cath, is preferably implanted. This procedure is well established, and hepatic catheters are regularly placed for local hepatic chemotherapy for ocular melanoma and colon cancer patients. A baseline biopsy may be taken during surgery.

A typical therapy regime might comprise the following:

Cycle 1: adenovirus construct administration diluted in 100 ml saline through the hepatic artery catheter, on days 1, 2 and 3.

Cycle 2 (day 29): adenovirus construct administration on days 1, 2, and 3 with concomitant administration of FUDR 0.3 mg/kg/d as continuous infusion for 14 days, via a standard portable infusion pump (e.g. Pharmacia or Melody), repeated every 4 weeks.

Safety of viral agent, and thus suitable dose, may be determined by Standard phase I dose escalation of the viral inoculum in a cohort of three patients per dose. If grade III/IV toxicity occurs in one patient, enrolment is continued at the current dose level for a total of six patients. Grade III/V toxicity in > 50% of the patients determines dose limiting toxicity (DLT), and the dose level below is considered the maximally tolerated dose (MTD) and may be further explored in phase II trials either as a single agent or in combination with the therapeutic agent.

For example, in such a combination trial, during the first cycle the virus can be administered alone, in order to determine toxicity and safety. For the second and subsequent cycles virus can be administered with concomitant chemotherapy. Safety and efficacy is preferably evaluated and then compared to the first cycle response, the patient acting as his or her own control.

It will be realised by those skilled in the art that the administration of toxic viruses may be accompanied by inflammation and or other adverse immunological event, which can be associated with e.g. cytokine release. In this event it is appropriate that an immuno-suppressive, anti-inflammatory or otherwise anti- cytokine medication is administered in conjunction with the virus, e.g., pre-, post- or during viral administration. Typical of such medicaments are steroids, e.g., prednisolone or dexamethasone, or anti-TNF agents such as anti-TNF antibodies or soluble TNF receptor, with suitable dosage regimes being similar to those used in autoimmune therapies. For example, see doses of steroid given for treating rheumatoid arthritis (see WO93/07899) or multiple sclerosis (WO93/10817).

The methods described in the following publications, incorporated herein by reference, which have recently been utilised in clinical trials of toxic viruses, may also be suitable for administration of the virus in the practice of the invention: Khuris et al., Nat Med. 2000 Aug;6(8):879-85, describes intratumoral injection; Nemunaitis J et al., Cancer Gene Ther. 2003 May; 10(5):341-52, describes intravenous injection; and Reid et al., Cancer Res. 2002 Nov l;62(21):6070-9 2002, describes hepatic artery infusion. Hepatic artery infusion is preferred when treating tumours in the liver.

The present invention will now be described by way of illustration only by reference to the following non-limiting Examples, Methods, Sequences and Figures. Further embodiments falling within the scope of the claims will occur to those skilled in the art in the light of these.

FIGURES

Figure 1. Adenoviruses used in this study, part/pfu: the ratio of particles measured by OD ₂₆₀ to PFU measured on HER911 cells.

Figure 2. Western blot analysis of ElA, DBP and fibre protein expression. SW620, SW480, HT29, Hctllβ and LS174T cells were infected at a moi of 100. HeLa cells were infected at a moi of 1000. Samples were collected at the indicated time points.

Figure 3. CPE assay on colon cancer cell lines (SW620, SW480, LS174T, HT29 and Hctllό) and HeLa cells. Cultures were infected withl 0-fold dilutions of virus starting at a moi of 1000, and stained with crystal violet on day 6 for SW620 and day 8 for the rest.

Figure 4. FISH for viral DNA in tumours 5 days after intravenous injection of 10 ¹¹ particles of vKHl and vKH6. Red: viral DNA (FISH); blue: cell nuclei (DAPI).

Figure 5. Biodistribution of vKHl, vKH3 and vKH6 24 hours after i.v. injection of 10 ¹¹ particles of virus. Each bar represents 3 individual experiments. Viral DNA was measured by quantitative PCR.

Figure 6. Liver histology three days after i.v. injection of virus, (a), 10 ¹⁰ particles wild type Ad5; (b), 10 ¹¹ particles vKHl; (c), 10 ¹¹ particles vKH6. Arrows in c show inflammatory infiltrates around the central vein.

Figure 7. Growth curves of subcutaneous SW620 colon carcinoma xenografts in NMRI nu/nu mice. Viral treatment started when tumours reached -100 mm ³ . Circles,

vKHl. Triangles, vKH6. Closed symbols: 10 ¹¹ particles of virus i.v. on day 0. Open symbols: 10 ¹¹ particles of virus i.v. on days 0, 7 and 14. 5, control (buffer injection).

Figure 8. FISH for viral DNA in tumours at the following times after i.v. injection of 10 ¹¹ particles of virus: (a), 3 days; (b), 6 days; c & d, 9 days. The whole tumour is shown in (d) to demonstrate the patchy distribution of virus. Original magnification: (a)-(c) 1Ox, (d) 2.5x. Red: viral DNA (FISH); blue: cell nuclei (DAPI).

Figure 9. Effect of RADOOl on virus infection in vitro, (a), Western blot analysis of ElA, DBP and fibre protein expression 24 and 48 hours after infection, (b), Viral DNA replication was analysed by quantitative PCR 48 hours after infection, (a) & (b), 3.6 μM RADOOl was added 4 hours after infection at an moi of 1. (c), CPE assay in the presence (+) or absence (-) of 3.6 μM RADOOl. Cultures were infected with 10-fold dilutions of virus starting at a moi of 1000, and stained with crystal violet on day 6. (d), MTT assay. SW480 cells were infected with 3-fold dilutions of virus starting at a moi of 1000, and harvested for MTT conversion on day 6.

Figure 10. Effect of RADOOl on virus replication and host antibody response in vivo, (a), Quantitative PCR for viral DNA in tumours six weeks after virus injection. The mice received one or three days of virus treatment and daily RADOOl 5 mg/kg/day. (b), FISH for viral DNA in a tumour six weeks after i.v. injection of 10 ¹¹ particles of vKHl and daily RADOOl. Red: viral DNA (FISH); blue: cell nuclei (DAPI). Original magnification 40x. (c), ELISA for anti-adenovirus antibody. Groups of four mice received RADOOl 10 mg/kg/day or placebo for 5 days followed by i.v. injection of 10 ⁹ particles of vKHl. The titre of anti-adenovirus antibodies in serum was measured by ELISA 21 days after infection.

Figure 11. Effect of RADOOl on tumour response in vivo.

(a) & (b), Growth curves of subcutaneous SW620 xenografts in NMRI nu/nu mice (5 per group), (a), i.v. injection of 10 ¹¹ particles of the virus on day 0; (b), i.v. injections of 10 ¹¹ particles of the virus on days 0, 7 and 14. σ, vKH6 and daily RADOOl 5 mg/kg/day; λ, vKHl and daily RADOOl 5 mg/kg/day; v, daily RADOOl 5 mg/kg/day; 5, control. The control group received placebo (RADOOl vehicle) by daily gavage. (g)

shows the growth curve for an earlier study (6 mice per group) using vKHl (day 0) and RADOOl (daily). The combination of virus and RADOOl completely stopped tumour growth.

(c)-(f), Kaplan-Meier curves showing the fraction of mice with SW620 xenografts below 1000 mm ³ in figures 7, 11 (a) & 1 l(b).

Figure 12. Histology of subcutaneous SW620 xenografts in mice treated with RADOOl. (a), vKHl; (b), 5 mg/kg/day RADOOl. Haematoxylin and eosin staining. Original magnification 10x.

Figure 13. Alignment of Tcf and Tcf/HRE ITRs

Figure 14. Kaplan-Meier curve for PTK787 and vKHl and vCF265. SW620 xenografts treated with iv virus on day 0 and oral daily PTK787 by gavage thereafter. KHl+ means vKHl plus PTK787, 265+ means vCF265 plus PTK787. Time = days.

General Methods Chemicals

RADOOl (Everolimus) was supplied by Novartis (Basel, Switzerland) as dry powder for in vitro use and microemulsion for oral use. The powder was dissolved in ethanol and stored as 10 mM stock solution at -20° C. The microemulsion (2% RADOOl) and placebo emulsion were aliquoted and stored at -20°C.

Cell lines

The colon cancer cell lines SW620 (ATCC-CCL), HT29 (ATCC-HTB38), Hctl lό (ATCC-CCL247), U2OS (ATCC-HTB96) and 293 cells (ATCC-CRLl 573) were obtained from the American Type Culture Collection (Rockville, Maryland). LS174T (ATCC-CL188) and SW480 (ATCC-CCL228) were provided by Dr B. Sordat. HeLa (CCL-2) cells were provided by Dr D. Lane. All cells were cultured in DMEM (Invitrogen, Carlsbad, USA) with 10% FBS, 1 % penicillin/streptomycin.

Viruses

EXAMPLE 1: Tcf promoter driven ElA. ElB and E4

The EIB-Tcf integrating vector, pRDI-241, was described by Brunori et al (1). The KpnllXbal Ad5 fragment (nt 30470 to 33598) containing the fibre region was cloned from Ad5 genomic DNA (ATCC VR5) into ρUC19 to give ρCF159. The CDCRGDCFC motif was inserted into the HI loop of the fibre by inverse PCR from pCF159 using primers (SEQ ID NO.l)

GGAGACTGTTTCTGCCCAAGTGCATACTCTATGTC (oKHll) and (SEQ ID NO.2) GCGGCAGTCACAAGTTGTGTCTCCTGTTTCCT (OKH12) to create pKH67. The Coxsackie- Adenovirus Receptor (CAR) binding site was mutated in the knob of the fibre by inverse PCR from ρKH67 using primers (SEQ ID NO.3) GGTGGTGGAGATGCTAAACTCACTTTGGTC (OKH9) and (SEQ ID NO.4) ATTTAGACTACAGTTAGGAGATGGAGCTGG (OKHIO) to create pKH68. The KpnVXbal fragments of pKH67 and pKH68 were cloned into pRS406 (6) to create ρKH69 (RGD insertion) and ρKH70 (RGD insertion and CAR deletion), the mutant fibre integrating vectors. The adenovirus genome was modified by two-step gene replacement as described by Gagnebin et al (3). First, the Tcf-EIB sites were inserted into vpCFl 1 (Tcf-EIA and Tcf-E4) (2) using pRDI-241 to create vpKHl. Subsequently, the fibre mutations were inserted in vpKHl using pKH69 and pKH70 to create vpKH3 and vpKH6, respectively. vKHl, vKH3 and vKH6 viruses were produced by transfection of Pad-digested vpKHl, 3 & 6 into cR2 cells (4). The viruses were then plaque purified on SW480 cells, expanded on SW480 cells using Cell factories (NUNC, Denmark), purified by double CsCl banding, buffer exchanged using HR400 columns (Amersham, UK) into 1 M NaCl, 100 mM Tris-HCl (pH 8.0), 10% glycerol, and stored frozen at -70°C. The identity of each batch was checked by restriction digestion and automated fluorescent sequencing in the ElB (nt 1300 to 2300) and fibre (30470-33598) regions using the following primers: (SEQ ID NO.5) ElB sense, TGT CTG AAC CTG AGC CTG AG; (SEQ ID NO.6) fibre antisense, CTA CTG TAA TGG CAC CTG; (SEQ ID NO.7) fibre sense, GCC ATT AAT GCA GGA GAT G. Apart from the desired mutations, no differences were found between the sequences of VR5 and the Tcf viruses. Particle counts were based on the optical density at 260 nm (OD ₂₆₀ ) of virus in 0.1% sodium dodecyl sulphate, using the formula 1 OD ₂₆₀ = 10 ¹² particles/ml.

EXAMPLE 2. HRE enhanced virus.

Viruses vCF265 was created which is identical to vKHl except for the presence of HREs in the El A promoter.

Construction of vCF265 was by gap repair using the same vectors as for vKHl, but HREs were inserted into a BgIII site before the TATA box in the left ITR Pacl/Sall fragment of the gap repair vector using oligos oCF121 (gatctggggtGCGTGtcgcgacgCACGCgcctcg) and oCF122

(gatccgaggcGCGTGcgtcgcgaCACGCacccca). The sequence alignment of the Tcf and Tcf/HRE ITRs is given in Figure 14.

The sequence starts with the Pad site, is followed by the ITR, and ends with the ElA TATA box. The region which does not align contains optimised HREs based on the CXCR4 HRE.

Western blotting

Cells were infected with 100 particles/cell in DMEM, except for HLF and U2OS which were infected with 1000 particles/cell. Two hours after infection, the medium was replaced with complete medium. Cells were harvested at the indicated times in SDS-PAGE sample buffer. ElA, DBP and fibre were detected with the M73 (Santa Cruz Biotechnology, Santa Cruz, USA), B6 (5) and 53 4D2 (Research Diagnostics Inc, Flanders, USA) antibodies, respectively.

Cytopathic effect assay

Cells in six- well plates were infected with 10-fold dilutions of virus in DMEM. Four hours after infection, the medium was replaced with complete medium containing RADOOl (Everolimus, Novartis, Basel, Switzerland). Four days after infection, new medium containing RADOOl was added. After 5-8 days, the cells were fixed with 4% formaldehyde in PBS and stained with crystal violet.

MTT assay

5000-10000 cells per well were seeded in complete medium in 96 well plates. 24 hours later cells were infected with serial dilutions of the viruses starting from 1000 particles/cell. After 6 days, 10 μl MTT reagent (Thiazolyl blue 98%, Sigma M5655) was added to the medium for 4 hours. The cells were then centrifuged, the

medium was removed and the wells were dried for 30 min. After addition of 100 μl isopropanol the absorbance was read at 570 run. Cell killing was normalised to mock infected cells.

Quantitative PCR assay

Cells were infected with 1 viral particle/cell in DMEM. Four hours after infection, the medium was replaced. 48 hours later DNA was purified using a DNeasy kit (Qiagen, Hilden, Germany) according to the manufacturer's instructions. Quantitative PCR was performed on a Light Cycler (Roche, Basel, Switzerland) using FastStart DNA Master SYBR Green I mix (Roche), 500 nM primers (Invitrogen, Carlsbad, USA) and 10 ng template DNA. Results were normalised to the amount of input DNA measured by OD ₂₆₀ . The primers used for quantitative PCR were: (SEQ ID NO.8) hexon forward primer CTTCGATGATGCCGCAGTG; (SEQ ID NO.9) hexon reverse GGGCTCAGGTACTCCGAGG.

Animal experiments

Four week old NMRI nu/nu mice were purchased from Elevage Janvier (Le Genest St Isle, France). Subcutaneous SW620 flank xenografts were made by injecting 10 ⁷ cells under isoflurane anaesthesia. Mice were injected with virus when tumours reached 80-150 mm ³ in size. A total of 1 x 10 ¹¹ particles were injected into the tail vein per day, given as four shots of 2.5x10 ¹⁰ particles at four hourly intervals. Two regimens were tested: virus injection on a single day at the start of the experiment (total dose per mouse 1 x 10 ¹¹ particles), or virus injection at weekly intervals for three weeks (total dose 3 x 10 ¹¹ particles). RADOOl microemulsion was diluted in water and 5 mg/kg/day was administered by daily gavage starting the day after virus injection. For mice receiving weekly injections of virus, RADOOl was omitted the day before and on the day of the injection (ie, on days 6, 7, 13 and 14). RADOOl administration continued daily thereafter to the end of the experiment. Tumour size was measured every two days. Tumour volume was calculated according to the formula, volume = length x width ² x 3.14/6.

ELISA

Three weeks after injection of 10 ⁹ viral particles of adenovirus (vKHl), 200 μl of blood was taken from each mouse, allowed to clot and serum was collected after

centrifugation at 3000 rpm for 10 min. ELISA plates (NUNC, Denmark) were coated with virus by incubation with 10 ⁹ viral particles of Ad5 in 100 μl PBS for 18 hours. After incubation the wells were washed 5 times with Ix PBS, 0.1% Tween-20 and blocked with 3% BSA, Ix PBS, 0.1% Tween-20 for 90 min. Serial dilutions of the serum were made in Ix PBS, 0.1%, Tween-20 and the wells were incubated with the different dilutions for 2 hours. Wells were washed with Ix PBS, 0.1% Tween-20 and then HRP-conjugated rabbit anti-mouse antibody diluted 1:2000 dilution in Ix PBS, 0.1% Tween-20 for 30 min was added. The wells were washed again with Ix PBS, 0.1% Tween-20 and HRP was detected by adding 50 mM citric acid, 100 mM Na ₂ HPO ₄ Ix PBS, 1 tablet of 3', 3', 5', 5'-tetramethylbenzidine, 2 ul 0.005% H ₂ O ₂ and read in a spectrophotometer at 450 nm.

FISH

Tumour samples were fixed in 4% paraformaldehyde (PFA), Ix PBS at 4°C for 4 hours. After fixation samples were moved into IxPBS and kept at 4 ⁰ C. 4 μm sections were prepared, fixed in 4% PFA, IxPBS for 15 min, washed in Ix PBS and digested for 30 min with lmg/ml proteinase-K in IM Tris-HCL, 0.5M EDTA at 37°C. Slides were washed again in Ix PBS for 5 min, acetylated with TEA pH 8 for 10 min, washed again for 5 min and covered with hybridization buffer without probe at 50°C for 2 hours. Probe was added and slides were hybridized overnight at 50°C. Probe was prepared using the Roche DNA labelling mix. Briefly, 100 ng of viral DNA was heated for 10 min at 100 ⁰ C in 8 μl dw. The tube was than quickly chilled on ice. 2 μl of 10x buffer (50OmM Hepes pH 6.6, 50 mM MgCl ₂ 20 mM DTT), 2 μl of 10x DIG DNA labelling mix (Roche), 6 ul of random hexamers (1 mg/ml), 2 μl of Klenow polymerase (1 U/μl) were added and incubated at 37°C for 1 hour. The reaction was stopped by freezing at -20°C. The free DIG-11-dUTP was removed using QIAquick Nucleotide Removal Kit (Qiagen). After overnight hybridisation, slides were washed first with 5x SSC for 5 min at room temperature then at 42°C with 5x, 0.2x, O.lx, O.lx SSC for 10, 15, 20 and 20 minutes, then with O.lx SSC at room temperature for 5 min. After washing, slides were incubated with buffer 1 (100 mM pH 9.5 Tris, 150 mM NaCl) for 5 min then with buffer 2 (5g/l BSA, 10 g/1 Roche

blocking reagent in buffer 1) for 2 hours, then incubated overnight with anti-DIG HRP in buffer 2 at 4 ⁰ C.

The following day slides were washed 5 times with Ix PBS, incubated with TSA Cy3 reagent kit (Perkin Elmer) for 10 minutes, washed 5 times with Ix PBS and incubated with DAPI for 10 min. Finally, slides were washed in Ix PBS and covered with DABCO and a coverslip. Photos were taken with DC200 and Axioplan microscopes.

RESULTS

The structure of the viruses used in this study is shown if figure 1. The parental virus, vKHl, has Tcf sites inserted into the inverted terminal repeats (ITRs) and ElB promoter, resulting in Tcf-dependent expression of ElA, ElB and, to a lesser extent, E4 (Fuerer & Iggo, 2002). The peptide CDCRGDCFC was inserted into the HI loop of the fibre gene of vKHl to produce vKH6, which is able to infect cells either through the normal CAR route or through binding to integrins, particularly α _v β ₃ and α _v β ₅ . The CAR binding site in the fibre gene of vKH6 was deleted to create vKH3. To avoid selective pressure to escape from the Tcf-based regulation of the early promoters, the vKH viruses were produced in SW480 cells, which have constitutively high Tcf activity because of a mutation in the APC gene. The particle to PFU ratio of the viruses is shown in figure 1, based on infection of HER911 cells, which are permissive for the Tcf viruses because of transcomplementation of the regulated promoters. CAR plays a major role in HER911 infection, resulting in a much higher particle to PFU ratio for vKH3 than for the other viruses. To avoid infecting cells with units of virus defined according to uninterpretable criteria, particle counts rather than PFU were used to calculate the viral titre for the experiments described below.

Western blotting for the ElA, DBP and fibre proteins was performed to test whether the Tcf viruses are able to infect colon cancer cells efficiently and retain selectivity. Three colon cancer cell lines with strong Tcf activity, SW480, SW620 and LS174T, and two colon cancer cell lines with weak Tcf activity, HT29 and Hctl lό, were tested. A cervical cancer cell line without activation of the Wnt pathway, HeLa, was used as a negative control. Viral protein expression by the Tcf viruses was reduced or absent in HeLa cells, confirming our previous results with Tcf-regulated viruses and showing that fibre modifications do not affect promoter activity (figure

2). The RGD viruses were as good as vKHl in all of the colon cancer cell lines, and showed substantially higher viral protein expression in LS 174T ₅ indicating that integrin binding plays an important role in infection of these cells.

To determine whether the RGD insertion changes the in vitro efficacy of the viruses, cytopathic effect assays (CPE) were performed (figure 3). At multiplicities of infection below 1 particle/cell, virus must undergo multiple rounds of productive infection to kill all the cells. Insertion of RGD into the fibre increased the efficacy of the virus on colon cells by a factor of 10-100. vKH3, in which the CAR binding site in the fibre has been deleted, showed intermediate toxicity in LS174T and Hctllδ, indicating that both CAR and integrins are used by vKH6 to infect these cells. The efficacy of vKH6 was comparable to, or greater than, that of wild type Ad5 in all of the colon cancer cell lines tested except HT29, which have the lowest Tcf activity. The CPE assay on HeLa cells showed that the tumour selectivity of the viruses was not affected by the fibre changes. vKHl and 3 were 10000-fold less cytopathic on the HeLa cells than wild type virus. vKH6 was 10-fold more cytopathic than the other Tcf-regulated viruses on HeLa cells, showing that integrins and CAR both contribute to HeLa infection. We conclude that the new viruses retain selectivity for colon cancer cells and show similar or greater toxicity than the parental virus. This is consistent with previous reports on the behaviour of RGD-modified oncolytic adenoviruses (Dmitriev et al., 1998).

To determine whether RGD insertion alters the pattern of Tcf virus infection in vivo, virus was injected into the tail vein of nude mice with subcutaneous SW620 xenografts. The virus was injected in four aliquots at four hourly intervals. This schedule was used to prolong the circulation time of the virus in the blood and hence the probability of infection (Tao et al., 2001): the first dose is rapidly cleared by Kupffer cells, which are themselves eliminated in the process. Fluorescent in situ hybridisation (FISH) to viral DNA was used to identify sites of virus replication (single viral genomes were below the detection limit of the assay). Nine days after injection, vKHl produced compact islands of infected cells, whereas vKH6 produced a more diffuse pattern, suggesting that vKH6 may spread better through tumour tissue (fig 4). To determine whether the spectrum of organs infected was altered by insertion of the RGD peptide, which binds to multiple different integrins, the biodistribution was tested (fig 5). Virus was injected into the tail vein and organs were harvested for quantitative PCR 24 hours later. The amount of viral DNA was 10-100 times higher

in the tumours infected with the RGD viruses, consistent with the in vitro data showing that SW620 is more susceptible to infection with vKH6 than vKHl. Liver is a major target organ for adenovirus after intravenous injection. The amount of viral DNA was similar in all mouse organs except liver, where the amount was increased 50-fold for vKH3 and vKH6. Wild type adenovirus is lethal after intravenous injection of doses over 10 ¹¹ particles (fig 6(a)). This is caused by virus replication in mouse liver cells and fulminant hepatocyte necrosis (Duncan et al., 1978). None of the mice treated with the Tcf viruses developed fatal liver necrosis after injection of 10 times the lethal dose of wild type virus (fig 6(b) & (c)). Consistent with the increased liver infection seen by quantitation of viral DNA, there was an inflammatory infiltrate in the region around the central veins of the mice receiving vKH6 (fig 6(c)). This is consistent with the increased liver infection noted by quantitative PCR, but the lack of overt signs of illness in the mice receiving the Tcf viruses indicates that the increased ability of the RGD viruses to infect the liver is more than offset by the reduction in toxicity caused by Tcf-regulation of the early promoters.

Given the increased ability of vKH6 to infect SW620 cells in vivo, xenograft growth was analysed after intravenous injection of virus. Two regimens were compared: injection on a single day (total 10 ¹¹ particles injected), and injection at weekly intervals for two weeks (total 3 x 10 ¹¹ particles injected). In both cases, the virus was fractionated on the day of injection to circumvent Kupffer cell clearance. Injection at weekly intervals was more effective than injection on a single day, and vKH6 was better than vKHl (fig 7). Even in the best case, however, all of the tumours eventually relapsed. Quantitative PCR showed that there was a large amount of viral DNA present in the tumours at the time of relapse. To understand why this virus had failed to control tumour growth, tumours were examined for viral DNA by FISH at different time points. Three days after infection, virus was found in isolated clusters of cells, corresponding to the cells initially infected with the injected virus and its progeny after one cycle of replication (fig 8(a)). At later time points, the regions infected expanded to form confluent areas of infection in some parts of the tumour (fig 8(b) & (c)). Relapse can be explained by uncontrolled growth of large areas of tumour that are devoid of virus (fig 8(d)). This is consistent with theoretical models showing that tumour cell spread generally outpaces virus spread (Wein et al., 2003).

To solve this problem one can try to increase the number of cells infected initially, for example by reducing losses in the circulation or by modifying the tropism to make the infection more selective for tumours. Alternatively, one can try to reduce the rate of tumour cell growth to allow more time for the virus to spread through the tumour nodule. Cytotoxic chemotherapy has been shown to increase the efficacy of toxic viruses (Heise et al., 1997), but the drugs normally used to treat colon cancer are unattractive for combination therapy because they can all kill the virus: irinotecan inhibits topoisomerase I, 5-fluorouracil blocks nucleotide synthesis, and oxaliplatin cross-links DNA. It has been suggested that they act synergistically by sensitising the cells to ElA, but in the complex situation in vivo it is difficult to distinguish this from a partial additive effect. Newer more selective agents offer the possibility to inhibit tumour cell growth without killing the virus. Among these drugs, the mTOR kinase inhibitor RADOOl (everolimus), an orally active derivative of rapamycin, is particularly useful in the practice of the present invention. This is because it combines three useful properties: it inhibits tumour cell growth directly, it blocks angiogenesis and it suppresses the immune response.

To determine whether RADOOl interferes with translation of viral proteins, a Western blot was performed in the presence or absence of RADOOl. There was no evidence of inhibition of either early or late protein expression (fig 9(a)), ElA and DBP are expressed early and late, fibre only late. Quantitation of viral DNA 48 hours after infection showed only small effects of RADOOl (in most cell lines there was a slight increase in replication in the presence of the drug, (fig 9(b)). In vitro efficacy was tested in CPE and MTT assays (fig 9(c) & (d)). Both showed either no effect or a 5 to 10-fold increase in efficacy in the presence of the drug. To show whether RADOOl inhibits replication in vivo a SW620 xenograft was infected by the intravenous route as above, and the amount and distribution of viral DNA in the tumour was examined after six weeks treatment of the mice with daily RADOOl by gavage. Quantitative PCR showed that a large amount of viral DNA was present in tumours after treatment with RADOOl for six weeks (fig 10(a)). Widespread areas of the tumour were positive by FISH for viral DNA after six weeks of treatment (fig 10(b)). Some of the FISH signal comes from cell debris in areas of necrosis, but the strongest signals are from the nuclei of living cells that are undergoing productive viral infection. We conclude that RADOOl does not inhibit viral growth in tumour

cells in vitro or in vivo. RADOOl is known to suppress T cell-dependent immune responses.

To confirm that it can prevent induction of a primary antibody response against adenovirus, an ELISA was performed in immune competent mice treated with RADOOl and then immunised with adenovirus (fig 10(c)). As expected, RADOOl was able to block the primary antibody response to virus.

The efficacy of combination therapy with toxic virus plus RADOOl was tested using two regimens. The virus itself was given according to the same schedules as before (fig 7). For single day virus treatment, RADOOl was given daily by gavage starting the day after injection of virus. For three days of virus treatment at weekly intervals, RADOOl was given daily except on the day preceding and the day of virus injection. RADOOl was omitted prior to virus injection to avoid possible interference with delivery of the virus to the tumour caused by anti- vascular effects of the drug. Mice treated with placebo (gavage with the vehicle used for the RADOOl) all had to be sacrificed because of uncontrolled tumour growth by day 20. This reflects the extremely rapid growth of this xenograft model once the tumours reach ~100 mm ³ . The start of the experiment had to be delayed until tumours had reached this size to ensure that they had developed a vascular tree which could be called on to deliver the virus after intravenous injection.

RADOOl alone was more effective than virus alone in slowing growth of the tumours, but at 40 days most mice still had to be sacrificed because of uncontrolled tumour growth (fig 11). Tumours treated with the combination showed markedly better responses: only one mouse in each vKHl plus RADOOl group had to be sacrificed, and no mice in either vKH6 plus RADOOl group had to be sacrificed before the end of the experiment, 40 days after the first virus injection (fig 11). The mechanism for the interaction between toxic virus and RADOOl most likely involves an effect on tumour blood vessels rather than a significant direct inhibitory effect on the tumour cells or inhibition of the immune response, given that the cells are relatively insensitive to the drug in vitro (fig 9(c)) the mice are immune deficient to allow xenografting. Histological examination of the tumours confirmed that RADOOl -treated tumours had the typical appearance of poorly vascularised tumours, with a rim of viable cells and a central necrotic core, in contrast with the untreated tumours, which contains large masses of viable cells with only patchy necrosis (fig 12).

HRE Virus results:

The Kaplan-Meier curves (Figure 14) show the time taken to reach a tumour size of 500 mm ³ . vCF265 was more effective than vKHl..

PTK787 as therapeutic drug for anti-angiogenesis

To test whether PTK787 can be usefully combined with a Tcf-regulated oncolytic adenovirus, SW620 xenografts were created and virus was injected intravenously as previously described. PTK787 was slightly more effective than vKHl alone. Addition of PTK787 significantly improved the survival of mice treated with either virus vCF265 and vKHl. This shows that addition of an anti- VEGFR drug increases the efficacy of a Tcf-regulated or a Tcf/HRE-regulated oncolytic adenovirus.

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