Patent Publication Number: US-2022211783-A1

Title: Gmci and ddri combination therapy for treating cancer

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Application No. 62/809,020 filed on Feb. 22, 2019, U.S. Application No. 62/874,639 filed on Jul. 16, 2019, and U.S. Application No. 62/908,152 filed on Sep. 30, 2019. 
    
    
     FIELD OF THE INVENTION 
     This disclosure is in the fields of molecular biology, immunology, and cancer therapy. 
     BACKGROUND 
     Cancer afflicts about 17 million people yearly worldwide. Commonly used methods of treating cancer include surgical resection, radiation therapy, chemotherapy, immunotherapy, oncolytic viral therapy, and combinations thereof. 
     More recently, cancer has been treated with gene-mediated cytotoxic immunotherapy (GMCI). GMCI utilizes a viral vector to deliver a gene which, when delivered to a target tissue and expressed, can activate a separately delivered prodrug that ultimately causes cytotoxicity and cell death due to resulting defects in the targeted cell&#39;s DNA repair mechanism 
     A component of GMCI activity is stimulation of the treated subject&#39;s immune response against the tumor cells. This mechanism of action involves activation and activation mitotic division of the patients&#39; immune cells in situ. However, cancer therapy using this modality is not always efficacious. For example, although studies have indicated that GMCI has some activity in brain cancer patients, improvements in commonly measured outcomes such as survival or tumor shrinkage have not been in all patient and are infrequently durable. 
     Another type of cancer therapy involves the administration of DNA damage response inhibitors (DDRI&#39;s) which stop the repair of breaks in single-stranded and/or double-stranded DNA. Both DNA double- and single-strand break repair are highly coordinated processes utilizing signal transduction cascades and post-translational modifications such as phosphorylation, acetylation and ADP ribosylation. DDRI&#39;s are a class of molecules which act on target proteins that function in pathway that perform DNA damage repair within a cell. DDRI targets include ataxia-telangiectasia mutated (ATM) kinase, WEE1 kinase, DNA-dependent protein kinase (DNA-PK), checkpoint kinase 1 (CHK1), checkpoint kinase 2 (CHK2) and poly(ADP-ribose) (PARP). 
     Unfortunately, DDRI&#39;s do not have efficacy in all patients or tumors within a patient, and tumor responses are not durable (Weber and Ryan 2015; Minchom et al. 2018); Minchom et al. 2018). For example, toxicities are commonly observed with DDR inhibitor drugs. These drugs may increase frequency of breakage at fragile sites of chromosomes, which may damage normal cells. In addition, DDRI&#39;s may limit DNA replication or inhibit DNA repair in normal cells. Patients treated with DDRI&#39;s in combination with chemotherapies such as temozolomide may suffer from thrombocytopenia and/or neutropenia. 
     The effectiveness of PARP inhibitors requires the subject have mutated BRCA1/2 genes. This limits the effective use of these agents to a to a smaller population of cancer patients. Increasing efficacy of these agents in patient without BRCA1/2 mutations would provide benefit to many cancer patients. 
     Few examples currently exist where tumor-type sensitivities to DNA-damaging agents are so clear-cut. In fact, there are examples where loss of a specific DDR pathway results in resistance to DNA-damaging agents, such as the resistance of mismatch repair-deficient tumors to monofunctional alkylating agents such as temozolomide 
     While GMCI and DDRI each have anti-tumor activity, improvements in their use are desired to provide better clinical outcomes such as improves survival, increased times to disease progression, increase frequency of tumor responses, increased durability of responses, increased tumor cell killing, enhanced immune activity against tumor cells, decreased toxicities, decreased dosages of the drugs required for efficacy, improved dosing schedules of the drugs. 
     SUMMARY 
     It has been discovered that treatment of a cancer or tumor in a subject with a combination of GMCI and inhibitors of certain DNA damage repair agents has synergistically greater effects (i.e., at least greater than the effects of each added together) than the effects provided by either GMCI or the use of inhibitors of certain DNA damage repair agents, alone. For example, the cytotoxicity delivered from treating a cancer with a combination of GMCI and an inhibitor of ataxia-telangiectasia mutated (ATM) kinase, WEE1 kinase, DNA-dependent protein kinase (DNA-PK), checkpoint kinase 1 (CHK1), checkpoint kinase 2 (CHK2), or (poly(ADP-ribose) polymerase (PARP), is unexpectedly greater compared to the cytotoxicity delivered when treating the cancer with GMCI or one of these inhibitors, alone (or greater than the cytotoxicity of both added together). In addition, the combination therapy results in more rapid killing of cancer cells and more rapid tumor shrinkage than was found when either therapy, alone, is used. Also, tumor responses to treatment more frequently occurs in patients treated with the combination, than in patients treated with only GMCI or the DNA damage repair inhibitors listed above. In addition, tumor responses that occur in patients treated the combination of GMCI and one of the DNA damage repair inhibitors listed above are more frequent, of greater magnitude, and are more durable than those treated with GMCI or one of the inhibitors, alone. 
     These discoveries have been exploited to provide the present disclosure, which in part provides methods of treating a cancer, tumor, and/or micrometastasis in a subject, comprising treating the subject with a combination of gene-mediated cytotoxic immunotherapy and a DNA damage response inhibitor which is not an ATR inhibitor. The disclosure also provides the use of GMCI and a DDRI in the treatment of a cancer, a tumor, and/or a micrometastasis. 
     In one aspect, the disclosure provides a method of decreasing tumor burden and/or micrometastasis in a subject, comprising administering to the subject a combination of gene-mediated cytotoxic immunotherapy (GMCI) and a DNA damage response inhibitor (DDRI) which is not an ATR inhibitor. 
     In some embodiments, GMCI comprises: administering a viral vector encoding thymidine kinase or cytosine deaminase to the mammal with a tumor or to a tumor resection site in the mammal; and administering a prodrug to the mammal, the prodrug being activated by thymidine kinase or cytosine deaminase 
     In certain embodiments, the vector is an adenovirus, an adeno-associated virus (AAV), a lentivirus, a retrovirus, a herpes virus, a New Castle Disease Virus, a coxsackievirus, or a vaccinia virus. In specific embodiments, the viral vector is replication-incompetent. 
     In some embodiments, the prodrug comprises ganciclovir, acyclovir, valacyclovir, valgancyclovir, famiciclovir, or an analog thereof. In other embodiments, the prodrug comprises de 5-Flurocytosine or an analog thereof. 
     In some embodiments, DDRI administration is before, during, or after GMCI administration. In certain embodiments, the DDRI comprises a ATM inhibitor, a DNA-PK inhibitor, a PARP inhibitor, a CHK1 inhibitor, a CHK2 inhibitor, a WEE1 inhibitor, or a combination thereof. In specific embodiments, the ATM inhibitor comprises AZD0156, Wortmannin, CP-466722, KU-55933, KU-60019, or KU-559403. In other specific embodiments, the DNA-PK inhibitor comprises VX984 PI-103, NU7441, PIK-75, NU7026, PP121, CC-1 15, or KU-0060648. In other specific embodiments, the PARP inhibitor comprises Olaparib, Rucaparib, niraparib, talazoparib, or veliparib. In other specific embodiments, the CHK1 inhibitor comprises UCN-01, XL844, CBP501, AZD7762, LY603618, MK-8776, PF-00477736, LY2606368, 2e, CCT244747, CHIR-124, GNE-783, GNE-900, PD-321852, PD-407824, SAR-020106, SB-218078, S1181, V158411, CH-1, AR323, AR678, or AR458323. In other specific embodiments, the CHK2 inhibitor comprises UCN-01, XL844, CBP501, AZD7762, V158411, or LY2606368. In other specific embodiments, the WEE1 inhibitor comprises PD-407824 or PD-321852. 
     In some embodiments, the method further comprising administering radiotherapy and/or chemotherapy to, and/or performing surgery on, the mammal before, during, or following GMCI and/or administering the DDRI. 
    
    
     DESCRIPTION 
     Throughout this application, various patents, patent applications, and publications are referenced. The disclosures of these patents, patent applications, and publications in their entireties are hereby incorporated by reference into this application in order to more fully describe the state of the art as known to those skilled therein as of the date of the invention described and claimed herein. The instant disclosure will govern in the instance that there is any inconsistency between the patents, patent applications, and publications and this disclosure. 
     For convenience, certain terms employed in the specification, examples, and appended claims are collected here. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The initial definition provided for a group or terra herein applies to that group or term throughout the present specification individually or as part of another group, unless otherwise indicated. 
     The articles “a” and “an” are used herein to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article. By way of example, “an element” means one element or more than one element. 
     The term “or” is used herein to mean, and is used interchangeably with, the term “and/or,” unless context clearly indicates otherwise. 
     The term “about” is used herein to mean approximately, in the region of, roughly, or around. When the term “about” is used in conjunction with a numerical range, it modifies that range by extending the boundaries above and below the numerical values set forth. In general, the term “about” or “approximately” is used herein to modify a numerical value above and below the stated value by a variance of 20%. 
     As used herein, the term “administration” of an agent or drug to a subject includes any route of introducing or delivering the agent to a subject to perform its intended function. Administration can be carried out by any suitable route, including, but not limited to, orally, intratumorally, intracranially, parenterally (intravenously, intramuscularly, intraperitoneally, or subcutaneously), rectally, or topically. Administration includes self-administration and the administration by another. 
     As used herein, the term “cancer” refers to a class of diseases of humans and animals characterized by uncontrolled cellular growth. “Cancer” is used interchangeably with the terms “tumor,” “malignancy”, “hyperproliferation” and “neoplasm(s). The term “cancer cell(s)” is interchangeable with the terms “tumor cell(s),” “malignant cell(s),” “hyperproliferative cell(s),” and “neoplastic cell(s)” unless otherwise explicitly indicated. Similarly, the terms “hyperproliferative,” “hyperplastic,” “malignant” and “neoplastic” are used interchangeably, and refer to those cells in an abnormal state or condition characterized by rapid proliferation. Collectively, these terms are meant to include all types of hyperproliferative growth, hyperplastic growth, neoplastic growth, cancerous growths or oncogenic processes, metastatic tissues or malignantly transformed cells, tissues, or organs, irrespective of histopathologic type or stage of invasiveness. 
     The terms “DDRIs” and DNA damage repair inhibitors” refer to agents which stop or inhibit the repair of breaks in single-stranded and/or double-stranded DNA, and as used herein, including inhibitors of ataxia-telangiectasia mutated (ATM) kinase, WEE1 kinase, DNA-dependent protein kinase (DNA-PK), checkpoint kinase 1 (CHK1), checkpoint kinase 2 (CHK2), or (poly(ADP-ribose) polymerase, but do not include “ataxia telangiectasia- and rad3-related kinase inhibitors” or “ATRi&#39;s”. 
     As used herein, the term “effective amount” or “pharmaceutically effective amount” or “therapeutically effective amount” or “prophylactically effective amount” of a composition, is a quantity sufficient to achieve a desired therapeutic and/or prophylactic effect, e.g., an amount which results in the prevention of, or a decrease in, the symptoms associated with a disease that is being treated, e.g., a cancer. The amount of a composition administered to the subject will depend on the type and severity of the disease and on the characteristics of the individual, such as general health, age, sex, body weight and tolerance to drugs. It will also depend on the degree, severity and type of disease. In some embodiments, an effective amount of an oncolytic virus may be administered to a subject having cancer in an amount sufficient to exert oncolytic activity, causing attenuation or inhibition of tumor cell proliferation leading to primary and/or metastatic tumor regression. 
     As used herein, the term “immune response” refers to the concerted action of lymphocytes, antigen presenting cells, phagocytic cells, granulocytes, and soluble macromolecules produced by the above cells or the liver (including antibodies, cytokines, and complement) that results in selective damage to, destruction of, or elimination from the human body of cancerous cells, metastatic tumor cells, etc. 
     As used herein, the term “subject” refers to an organism administered one or more active agents. Typically, the subject is a mammal, such as an animal, e.g., domestic animals (e.g., dogs, cats and the like), farm animals (e.g., cows, sheep, pigs, horses and the like) and laboratory animals (e.g., monkey, rats, mice, rabbits, guinea pigs and the like). Typically, the terms “subject” and “patient” are used interchangeably herein in reference to a human subject. 
     As used herein, the terms “treating” or “treatment” or “alleviation” refers to both therapeutic treatment and prophylactic or preventative measures, wherein the object is to prevent or slow down (lessen) the targeted pathologic condition or disorder. For example, a subject is successfully “treated” for a cancer, if after receiving a therapeutic amount of the compositions described herein, the subject shows observable and/or measurable reduction in or absence of one or more signs and symptoms of the cancer, e.g., reduction in the number of cancer cells or absence of the cancer cells; reduction in the tumor size; inhibition of tumor metastasis; inhibition, to some extent, of tumor growth; increase in length of remission, and/or relief to some extent, of one or more of the symptoms associated with the specific cancer; reduced morbidity and mortality and improvement of life issues. 
     The present disclosure relates, in part, to a method of killing a cancer or tumor cells, and thus treating cancer by using a combination of therapies comprising gene-mediated cytotoxic immunotherapy and certain DNA damage response inhibitors. 
     I. GMCI 
     GMCI involves the administration of a viral vector carrying a gene encoding a cytotoxic protein to a subject afflicted with a cancer. When the viral vector is delivered to a target tissue in the subject, it expresses the gene, which, when in contact with a separately administered prodrug, activates the prodrug. The activated prodrug is cytotoxic to the cell and ultimately causes cell death due to resulting defects in the targeted cell&#39;s DNA repair mechanism. 
     A. Viral Vectors 
     Useful viral vectors include any viruses that can target a tissue and can carry a gene encoding a protein that can activate a prodrug. The viral vectors may be a virus that can replicate in the target tissue, or can be replication incompetent. Useful viral vectors include, but are not limited to, adenovirus, adeno-associated virus (AAV), lentivirus, retrovirus, herpes virus, New Castle Disease Virus, coxsackievirus, and vaccinia virus. 
     Useful genes to be carried by the viral vector are those genes which encode a “cytotoxic protein” that when expressed, is able to activate a prodrug, thereby causing a cytotoxic response. As used herein, “activates” means causes the prodrug to become cytotoxic. For example, activation of the prodrug may involve phosphorylation of the prodrug or its metabolite leading to the formation of a nucleotide analog that inhibits DNA repair by preventing DNA chain extension and DNA polymerase activity. This results in defective DNA repair in and around the targeted cancer cells, leading to cytotoxicity and ultimately, to cell death. Representative useful cytotoxic proteins include, but are not limited to, thymidine kinase and cytosine deaminase. 
     B. Prodrugs 
     Useful prodrugs include any that are in inactive form until they are contacted and activated by, the cytotoxic protein. Useful prodrugs administered in conjunction with thymidine kinase expressing vectors include, but are not limited to, ganciclovir, acyclovir, valacyclovir, valgancyclovir, famiciclovir, and analogs thereof. Useful prodrugs administered in conjunction with cytosine deaminase expressing vectors include  5 -Flurocytosine 
     II. DDRI&#39;s 
     Cancer cells may have weakened DNA repair and DNA-damage signaling capabilities compared to normal cells, and may be more susceptible to DNA damage repair inhibition than are normal cells. Because the key regulators within repair mechanisms, such as use either ATP or nicotinamide adenine dinucleotide for their enzymatic functions, they are readily accessible to small molecule inhibition at their catalytic sites. Useful targets to inhibit that are involved in the detection, signaling, and repair of double-stranded breaks include, ataxia-telangiectasia mutated (ATM) kinase, WEE1 kinase, DNA-dependent protein kinase (DNA-PK), checkpoint kinase 1 (CHK1), checkpoint kinase 2 (CHK2), and poly(ADP-ribose) polymerase (PARP). 
     Representative, nonlimiting ATM inhibitors include AZD0156, Wortmannin, CP-466722, KU-55933, KU-60019, and KU-559403. These inhibitors can be synthesized or can be commercially obtained. 
     Representative, nonlimiting DNA-PK inhibitors include VX984 PI-103, NU7441, PIK-75, NU7026, PP121, CC-1 15 and KU-0060648. These inhibitors can be synthesized or can be commercially obtained. 
     Representative, nonlimiting PARP inhibitors include Olaparib, Rucaparib, niraparib, talazoparib, and veliparib. These inhibitors can be synthesized or can be commercially obtained. 
     Representative, nonlimiting CHK1 inhibitors include UCN-01, XL844, CBP501, AZD7762, LY603618, MK-8776, PF-00477736, LY2606368, 2e, CCT244747, CHIR-124, GNE-783, GNE-900, PD-321852, PD-407824, SAR-020106, SB-218078, S1181, V158411, CH-1, AR323, AR678, and AR458323. These inhibitors can be synthesized or can be commercially obtained. 
     Representative, nonlimiting CHK2 inhibitors include UCN-01, XL844, CBP501, AZD7762, V158411, LY2606368. These inhibitors can be synthesized or can be commercially obtained. 
     Representative, nonlimiting WEE1 inhibitors include PD-407824 and PD-321852. These inhibitors can be synthesized or can be commercially obtained. 
     III. Combination Treatment 
     Treatment of a cancer in a subject according to the disclosure comprises treatment via a combination of GMCI, which includes the provision to the patient of a viral vector encoding a cytotoxic protein, administration of a prodrug activated by the cytotoxic protein, and DDRI administration of an inhibitor of certain DNA damage repair agents as described above. 
     Pharmaceutical formulations for this combination therapy comprise: (1) the viral vector; (2) the prodrug; and (3) the DNA damage repair inhibitor. These formulations are adapted to the route of administration and using a pharmaceutically acceptable carrier or diluent consistent with the chosen route of administration and which does not affect the activity of the viral vector, prodrug, or DDRI. In addition, pharmaceutically acceptable carriers or diluents are nontoxic to recipients at the dosages and concentrations employed. Representative examples of carriers or diluents for injectable solutions include water, isotonic saline solutions which may be buffered at a physiological pH or a pH for vector stability (such as phosphate-buffered saline or Tris-buffered saline), mannitol, dextrose, sucrose, glycerol, and ethanol, as well as polypeptides or proteins such as human serum albumin The formulations may be prepared either as a liquid solution, or in solid form (e.g., lyophilized) which is suspended in a solution prior to administration. The carriers and/or diluents in the formulations are suitable for surface administration, injection, oral, or rectal administration. 
     A. GMCI Administration 
     Formulated viral vectors or viral particles may be administered to a wide variety of tissue and/or cell types where cancerous lesions may exist, including for example, the brain and/or spinal cord, bone marrow, eyes, the liver, nose, throat and lung, heart and blood vessels, spleen, skin, circulation, muscles, prostate, breast, pancreas, kidney, cervix, prostate, and other organs. 
     Various methods may be utilized within the context of the present disclosure in order to administer the viral vector or viral particles to the tumor. Vectors may be administered either directly (e.g., intravenously, intramuscularly, intraperitoneally, intra-lesionally, intra-cavitally, subcutaneously, or intravesically, during surgical intervention) or indirectly (e.g., orally, rectally, intraocularly, intranasally,) to the site of a tumor lesion. Alternatively, other clinically acceptable means of administration may be used, such as by various forms of catheter that can be introduced into the patient with minimal discomfort, followed by injection or release of the vector in conjunction with operations made possible by the catheter, such as multiple injection, introduction of radioactive seeds, tissue disruption and other means known to those skilled in the art. In addition, the viral vector may be delivered after formulation by various physical methods such as lipofection, microprojectile bombardment, administration of nucleic acids alone or administration of DNA linked to killed adenovirus; via polycation compounds such as polylysine, utilizing receptor specific ligands; as well as with psoralen inactivated viruses such as Sendai or Adenovirus, by electroporation or by pressure-mediated delivery. 
     In a nonlimiting exemplary example, once a cancerous lesion is located, the vector formulation may be directly injected once or several times in several different locations within the body of the tumor. Alternatively, or additionally, arteries or blood vessels, which serve a tumor, may be identified and the vector injected into such blood vessel, in order to deliver the vector directly into the tumor. A tumor that has a necrotic center may be aspirated, and the vector injected directly into the now empty center of the tumor. The viral vector may be directly administered to the surface of the tumor, for example, by application of a topical pharmaceutical composition containing the viral vector. The vector may alternatively or additionally be administered by direct injection by other clinically acceptable means such as by various forms of catheter that can be introduced into the patient with minimal discomfort, followed by injection or release of the vector in conjunction with operations made possible by the catheter, such as multiple injection, introduction of radioactive seeds, tissue disruption and other means known to those skilled in the art. When the viral vector formulations are administered directly to the tumor or to the site of a resected tumor (where a tumor cell may still exist), from about 1×10 6  to 1×10 12  viral vector or viral vector particles are administered either into the tumor or in the wall of the resection cavity at a number of sites ranging from about 1 to about 50 injection sites with a total volume injected of about 100 μl to about 5000 μl. The total intravenous dose of the viral vector can range from about 1×10 7  to about 1×10 12  viral vectors or viral vector particles. 
     After the vector administration is completed, the prodrug formulation is administered. Administration can be oral or intravenous, depending on the prodrug. For orally administered prodrugs such as valacyclovir, dosing starts at about 1 days to about 3 days after viral vector administration at a dose between about 0.5 grams and about 2 grams orally about 1 to about 3 times a day for about 2 days to about 14 days. Certain patients, such as those with impaired renal function, may receive a modified dose schedule such as about 1.5 grams orally three times a day, or about 1.5 grams twice a day. Other prodrugs such as ganciclovir and acyclovir. Ganciclovir is administered intravenously at about 0.5 mg/kg to about 10 mg/kg up to twice daily for between about 5 days and about 14 days. Acyclovir is administered at about 5 mg/kg to about 20 mg/kg as frequently as every 8 hours for between about 5 days and about 14 days. 
     B. Administration of DNA Damage Response Inhibitors 
     DDRI treatment can be administered before, during, or after GMCI treatment. Details of the dosing of the DDRI, including the route of administration and dosage levels depend on the properties of the specific DDRI agent. These are typically characterized by balancing commonly used metrics of clinical efficacy (e.g., tumor shrinkage, survival, time to disease progression, improvements in symptoms) with side effects associated with administration of the drugs. For the well-characterized PARP inhibitors, initial dosing levels are frequently recommended, followed by dose reduction schedules as the alleviation of side effects is required. For olaparib, the initial dose may be about 600 mg/day, and if drug-related toxicities remain severe, reductions in dose to about 500 mg/day, orabout 400 mg/day are recommended (“Lynparaza (Olaparib)” 2019). For niraparib, initial dosing may be about 300 mg/day may be reduced to about 200 mg/day or about 100 mg/day as drug-related side effects require (“Zejula (Nirparib)” 2019). For talazoparib, initial dosing may be about 1 mg/day, with reductions to about 0.75 mg/day, about 0.5 mg/day, or about 0.25 mg/day depending on toxicities (“Talzenna (Talazoparib)” 2019). Rucaparib may be dosed at about 300 mg/day dosing with unspecified dose reductions based on side effects (“Rubraca (Rucaparib)” 2019). 
     Dosing of DDRI agents is frequently associated with toxicity, and accordingly it is common practice to gradually decrease the dosage of these drug in order to decrease DDRI-associated toxicities. Administration of the drugs is initiated at the high dose levels to provide optimal efficacy. When a patient is administered a combination of a DDRI agent with GMCI, lower doses of the DDRI can be used while achieving optimal efficacy (such as amount or duration of tumor response, or increase in survival of the cancer patient), with the toxicity of profile of the combination therapy being improved. 
     IV. Additional Associated Treatments 
     The combination therapy according to the disclosure can be used along with other cancer treatments, including, but not limited to standard cancer treatment modalities such as resectional surgery, radiation therapy, chemotherapy, and immune modulating therapies such as anti-checkpoint protein antibodies. The use of these additional therapies does not reduce the synergistic effect of the combination treatment. 
     V. Cancers to be Treated 
     Cancer that can be treated by the method according to the disclosure include solid tumors, liquid tumors, and metastases, and micrometastases. Tumors such as, but not limited to, hyperplastic or neoplastic disease, such as a carcinoma, sarcoma, or mixed type cancer, including breast, colorectal, endometrial, gastric, prostate or brain, mesothelioma, ovarian, lung or pancreatic cancer can be targeted for therapy using the present method. 
     VI. Monitoring of Treatment 
     Tumor cell death in vitro experiments can be measured using established methods such as assays for cell viability assays using agents such as MTT, MTS, or Alomar Blue and/or by standard clinical pathology methods of observing cell death by the analysis of necrosis in treated tissues. 
     Tumor size can be monitored using standard radiographic methods such as Magnetic Resonance Imaging (MRI) or Computed Tomography scan (CT Scan). Changes in tumor size are assessed using standard clinical criteria such as Response Evaluation Criteria In Solid Tumors (RECIST) or Immune Related Response Criteria (irRC) or Response Assessment in Neuro-oncology, or RANO Criteria. 
     VII. Synergistic Effects of the Combined Therapy 
     Unexpectedly improved and surprising anti-cancer results are obtained when therapies including GMCI and inhibitors of certain DNA damage repair agents are combined. The cytotoxic activity in tumor cells treated with the combination therapy is greater than the cytotoxic activity found in cells treated with only GMCI or an inhibitor of certain DNA damage repair agents and is greater and/or different than the additive effect of both. Further, the cytotoxicity measured when using the combination is more than the cytotoxicity found when using either therapy, alone or added together. 
     The combination theory results in more rapid killing of cancer cells and tumor shrinkage than was found when either therapy, alone, is used. Tumor responses to standard protocols (RECIST, irRC, RANO Criteria) occurs with more frequency in patients treated with the combination therapy, than in patients treated with only GMCI or only an inhibitor of certain DNA damage repair agents, alone. Also, tumor responses that occur in patients treated the combination therapy is greater and more durable than in patients treated with either treatment, alone. 
     When a patient is treated with the combination therapy, lower doses of the DNA damage inhibitor can be used while achieving optimal efficacy (such as amount or duration of tumor response, or increase in survival of the cancer patient), with the toxicity of profile of the combination therapy being improved. 
     A variety of mutations that inactive the BRCA genes (BRCA1 or BRCA2) are associated with some types of cancer including breast and ovarian cancer. The effective use of PARP inhibitors in the treatment of cancer has been limited to patients with inactivating mutations in the BRCA1/2 genes, a phenomenon termed “synthetic lethality”. Such pre-existing genetic perturbations resulting in synthetic lethality may be required for efficacy of many drugs in this class. This limits the number of patients in which such drugs can be used. However, when GMCI is combined with the administration of an inhibitor of certain DNA damage repair agents, the requirement for the patient to have perturbations resulting in synthetic lethality is reduced or eliminated. 
     Reference will now be made to specific examples illustrating the disclosure. It is to be understood that the examples are provided to illustrate exemplary embodiments and that no limitation to the scope of the disclosure is intended thereby. 
     EXAMPLES 
     Example 1 
     GMCI in Combination with ATM Inhibitor for Treatment of Brain Tumors 
     As per current standard of care, brain cancer patients typically undergo surgical removal of the tumor in followed by treatment with radiation therapy and temozolomide. Radiation therapy dosing is between about 70 Gy and about 80 Gy of radiation over a period of about 3 weeks to about 8 weeks. 
     The AdV-tk vector is injected into the resection cavity post-surgery. Between about 1×10 10  and about 1×10 12  vector particles are delivered in a total volume in the range of 0.5 ml and 2 ml over about 5 to about 50 sites within the surgical cavity. 
     The patient then receives a course of prodrug, valacyclovir. Prodrug treatment begins about 1 day to about 3 days after vector administration at a dose of approximately 2 g orally 3 times a day for 14 days. When a patient is unable to take the oral prodrug for any reason, intravenous acyclovir at 10 mg/kg tid is substituted. 
     Administration of the DDRI drug AZD1390 is initiated with the first dose about 1 day to about 7 days before surgery and AdV-tk injection. Continuous or intermittent dosing continues during the course of radiation therapy and for at least 2 weeks after the radiation course ends. AZD1390 is dosed orally at between 0.1 mg/kg and 100 mg/kg per day. 
     Clinical patient outcomes are monitored using standard methodology, including, but not limited to, at least one of tumor response, disease progression, quality of life, blood chemistry, immune system status, general wellness, and/or survival. 
     The patients receiving the combination treatment have improved outcomes when compared to patents with similar disease characteristics that receive current standard of care or either single agent alone. Improvements in outcomes include, but are not limited to, one or more of improved survival time post-treatment, increased time to disease recurrence, and/or a better quality of life. 
     Example 2 
     GMCI in Combination with a PARP Inhibitor for Treatment of Prostate Cancer 
     As per current standard of care, prostate cancer patients commonly undergo radiation therapy of the prostate. Radiation therapy dosing is between about 70 Gy and about 80 Gy of radiation over a period of about 3 weeks to about 8 weeks. 
     Three courses of GMCI are administered the first course of GMCI is started about 1 week to about 5 weeks before the initiation of radiation therapy. The second GMCI course is started in the first 3 weeks of radiation therapy. The third course of GMCI is started about 5 weeks to about 8 weeks after the initiation of radiation therapy. 
     For each course the AdV-tk vectors are injected into the prostate. Between about 1×10 10  and about 1×10 12  vector particles in a total volume of about 0.5 ml to about 2 ml are delivered over 4 sites within the prostate gland. For each course, after the injection of the vector, the patient receives a course of the prodrug, valacyclovir. Prodrug treatment begins about 1 day after vector administration at a dose of about 2 g orally 3 times a day for about 14 days. If a patient is unable to take the oral prodrug for any reason, intravenous acyclovir at 10 mg/kg patient weight is substituted. 
     Administration of the DDRI drug Olaparib, is initiated with the first dose about 1 day to about 7 days before, or 1 day to 14 days after the start of the first course of GMCI. Continuous or intermittent dosing continues during the radiation therapy course and for at least 2 weeks after the radiation course ends. Olaparib is dosed orally at between about 100 mg/day and about 750 mg/day. Dosing may be adjusted based on toxicities, while trying to maintain a dose sufficiently high to be effective in treating the cancer. 
     Clinical patient outcomes are monitored using standard methodology, including, but not limited to, at least one of tumor response, disease progression, quality of life, blood chemistry, immune system status, general wellness, and/or survival. 
     The patients receiving the combination treatment have improved outcomes when compared to patents with similar disease characteristics that receive current standard of care or either single agent alone. Improvements in outcomes include, but are not limited to, one or more of improved survival time post-treatment, increased time to disease recurrence, and/or a better quality of life. 
     Example 3 
     GMCI in Combination with an PARP Inhibitor for Treatment of Ovarian Cancer 
     As per current standard of care, ovarian cancer patients commonly undergo tumor debulking. After tumor removal, between about 1×10 10  and about 1×10 13  vector particles are administered intraperitoneally in a total volume of about 5 ml to about 500 ml. After vector administration, the patient receives a course of prodrug, valacyclovir. Prodrug treatment begins about 1 day after vector administration at a dose of about 2 g orally 3 times a day for about 14 days. If a patient is unable to take the oral prodrug for any reason, intravenous acyclovir at 10 mg/kg tid is substituted. 
     Administration of a DDRI drug such as niraparib is initiated about 1 day to about 10 days before the initiation of GMCI. Continuous or intermittent dosing of niraparib continues during the prodrug course, and continue for at least 1 week to 2 weeks after the prodrug course ends. 
     Clinical patient outcomes are monitored using standard methodology, including, but not limited to, at least one of tumor response, disease progression, quality of life, blood chemistry, immune system status, general wellness, and/or survival. 
     The patients receiving the combination treatment have improved outcomes when compared to patents with similar disease characteristics that receive current standard of care or either single agent alone. Improvements in outcome include, but are not limited to, improved survival time post-treatment, increased time to disease recurrence, and/or better quality of life. 
     Example 4 
     GMCI—WEE-1 Inhibitor Combination for Treatment of in vitro Luna Cancer 
     The combination of GMCI and a WEE-1 inhibitor (AZD1775) is examined for anti-cancer activity in lung cancer cells. 
     At the start of the study (Day 0), a lung cell line e.g., A549, A427, H2030 (American Type Culture Collection) is plated at a density of 5000 cells per well. For the samples on which GMCI is administered, on the following day (Day 1) AdV-tk vector is added at a concentration of approximately 5×10 4  vp/ml (100 MOI). Starting on Day 2, to the samples being treated with GMCI, ganciclovir is added to a concentration of 5 μg/ml. In samples exposed to AZD1775, starting at Day 2, AZD1775 is added at a concentration to either the EC 50  concentration (80 nM) of the drug, or half the IC 50  concentration (40 nM) of the drug, either in combination with GMCI or alone, as indicated. At Day 4, cell viability is assayed by the addition of a vial dye such as Presto Blue assay and quantified by fluorescence spectrometry. The viability of cells exposed to various regimens (GMCI, AZD1775, the combination of GMCI and AZD1775 or neither treatment). 
     After treatment of glioma cells as described, significant differences in the viability of the cancer cells are observed. Observed fluorescence, which is a measurement of viability in this assay, is normalized to samples that received no treatment. AZD1775 is observed to have cytotoxic activity when dosed at either its IC 50  concentration or half of its IC 50  concentration. GMCI also provides a decrease in cell activity indicating cytotoxic activity as previously observed. 
     When AZD1775 and GMCI treatments are combined, there is a large, unanticipated decrease in cell viability at either the IC 50  concentration of AZD1775 or half the IC 50  concentration of AZD1775. The decrease is greater than any observed with either agent by itself. 
     A statistical analysis is performed to demonstrate the synergy between GMCI and AZD1775 in the reduction of viability of cancer cells. Synergism is analyzed by the Combination Index (CI) calculation with the formula of Chou-Talalay (Chou 2010; Ting-Chao Chou 1984). CI values above 1.00 indicate antagonistic effect of combination agents; a CI of 1.00 indicates an additive effect; and CI values below 1.00 indicate synergistic effect. The calculated CI for GMCI with the ATRi at IC50 concentration is 0.8, and GMCI combined with ATRi at ½ IC 50  concentration is 0.9, indicating synergism. 
     In another experiment, the frequency of double-stranded DNA breaks in glioma cells treated with GMCI, or the combination is monitored. The formation of double-stranded DNA breaks is examined by staining the cells for H2AX-Ser139. 
     At the start of the study (Day 0), a lung cell line is plated at a density of 12,500 cells per well of a 24-well plate containing glass coverslips. For the samples to which GMCI is administered, AdV-tk vector is added at a concentration of approximately 1.25×10 6  vp/ml (100 MOI). Starting on Day 1, to the samples being treated with GMCI, ganciclovir is added to a concentration of 5 μg/ml. In samples exposed to AZD1775, starting at Day 1 AZD1775 is added at a concentration to the IC 50  concentration of the drug. either in combination with GMCI or alone, as indicated. At a timepoint 6 hours after addition of AZD1775 and/or GCV, the cells are fixed in 4% paraformaldehyde in phosphate buffered saline. After blocking with 5% donkey serum/0.5% Tween 20, 0.02% TX100/PBS for 1 hr at room temperature (RT), cells are washed 3 times with washing buffer (0.5% Tween 20, 0.02% TX100/PBS) and stained with H2AX Ser139 antibody (1:100). The next day the samples are washed and incubated for 2 hr with a fluorescently-tagged secondary antibody plus Hoechst 33342. Images are captured with a Zeiss LSM710 confocal microscope. 
     Double-stranded DNA breaks occur in treatment with GMCI and/or with WEE1i (AZD1775). 
     Confocal microscopic images of lung cancer cells after AdV-tk, GCV, and GMCI treatments show nuclear staining with an antibody specific for phospho-histone H2AX (Ser139) (anti-H2AX Ser139 (Product #9718, Cell Signal Technologies) in green and Hoechst in blue. Untreated cells show very little staining for H2AX(Ser139), whereas GMCI, AZD1775- and combination samples shows a large increase in H2AX staining. 
     Equivalents 
     The present invention is not to be limited in scope by the specific embodiments described which are intended as single illustrations of individual aspects of the invention, and any compositions or methods which are functionally equivalent are within the scope of this invention. Various modifications of the invention in addition to those shown and, described herein will become apparent to those skilled in the art from the foregoing description and accompanying drawings. Such modifications are intended to fall within the scope of the appended claims.