Integrating immunopeptidome analysis for the design and development of cancer vaccines.

The repertoire of naturally presented peptides within the MHC (major histocompatibility complex) or HLA (human leukocyte antigens) system on the cellular surface of every mammalian cell is referred to as ligandome or immunopeptidome. This later gained momentum upon the discovery of CD8 + T cells able to recognize and kill cancer cells in an MHC-I antigen-restricted manner. Indeed, cancer immune surveillance relies on T cell recognition of MHC-I-restricted peptides, making the identification of those peptides the core for designing T cell-based cancer vaccines. Moreover, the breakthrough of antibodies targeting immune checkpoint molecules has led to a new and strong interest in discovering suitable targets for CD8 +T cells. Therapeutic cancer vaccines are designed for the artificial generation and/or stimulation of CD8 +T cells; thus, their combination with ICIs to unleash the breaks of the immune system comes as a natural consequence to enhance anti-tumor efficacy. In this context, the identification and knowledge of peptide candidates take advantage of the fast technology updates in immunopeptidome and mass spectrometric methodologies, paying the way to the rational design of vaccines for immunotherapeutic approaches. In this review, we discuss mainly the role of immunopeptidome analysis and its application for the generation of therapeutic cancer vaccines with main focus on HLA-I peptides. Here, we review cancer vaccine platforms based on two different preparation methods: pathogens (viruses and bacteria) and not (VLPs, nanoparticles, subunits vaccines) that exploit discoveries in the ligandome field to generate and/or enhance anti-tumor specific response. Finally, we discuss possible drawbacks and future challenges in the field that remain still to be addressed.

Computationally prioritized drugs inhibit SARS-CoV-2 infection and syncytia formation.

The pharmacological arsenal against the COVID-19 pandemic is largely based on generic anti-inflammatory strategies or poorly scalable solutions. Moreover, as the ongoing vaccination campaign is rolling slower than wished, affordable and effective therapeutics are needed. To this end, there is increasing attention toward computational methods for drug repositioning and de novo drug design. Here, multiple data-driven computational approaches are systematically integrated to perform a virtual screening and prioritize candidate drugs for the treatment of COVID-19. From the list of prioritized drugs, a subset of representative candidates to test in human cells is selected. Two compounds, 7-hydroxystaurosporine and bafetinib, show synergistic antiviral effects in vitro and strongly inhibit viral-induced syncytia formation. Moreover, since existing drug repositioning methods provide limited usable information for de novo drug design, the relevant chemical substructures of the identified drugs are extracted to provide a chemical vocabulary that may help to design new effective drugs.

Characterization of Expanded Gamma Delta T Cells from Atypical X-SCID Patient Reveals Preserved Function and IL2RG-Mediated Signaling.

Abnormally high γδ T cell numbers among individuals with atypical SCID have been reported but detailed immunophenotyping and functional characterization of these expanded γδ T cells are limited. We have previously reported atypical SCID phenotype caused by hypomorphic IL2RG (NM_000206.3) c.172C > T;p.(Pro58Ser) variant. Here, we have further investigated the index patient's abnormally large γδ T cell population in terms of function and phenotype by studying IL2RG cell surface expression, STAT tyrosine phosphorylation and blast formation in response to interleukin stimulation, immunophenotyping, TCRvγ sequencing, and target cell killing. In contrast to his âºß T cells, the patient's γδ T cells showed normal IL2RG cell surface expression and normal or enhanced IL2RG-mediated signaling. Vδ2 + population was proportionally increased with a preponderance of memory phenotypes and high overall tendency towards perforin expression. The patient's γδ T cells showed enhanced cytotoxicity towards A549 cancer cells. His TCRvγ repertoire was versatile but sequencing of IL2RG revealed a novel c.534C > A; p.(Phe178Leu) somatic missense variant restricted to γδ T cells. Over time this variant became predominant in γδ T cells, though initially present only in part of them. IL2RG-Pro58Ser/Phe178Leu variant showed higher cell surface expression compared to IL2RG-Pro58Ser variant in stable HEK293 cell lines, suggesting that somatic p.(Phe178Leu) variant may at least partially rescue the pathogenic effect of germline p.(Pro58Ser) variant. In conclusion, our report indicates that expansion of γδ T cells associated with atypical SCID needs further studying and cannot exclusively be deemed as a homeostatic response to low numbers of conventional T cells.

Mannosylated Polycations Target CD206+ Antigen-Presenting Cells and Mediate T-Cell-Specific Activation in Cancer Vaccination.

Immunotherapy is deemed one of the most powerful therapeutic approaches to treat cancer. However, limited response and tumor specificity are still major challenges to address. Herein, mannosylated polycations targeting mannose receptor- are developed as vectors for plasmid DNA (pDNA)-based vaccines to improve selective delivery of genetic material to antigen-presenting cells and enhance immune cell activation. Three diblock glycopolycations (M15A12, M29A25, and M58A45) and two triblock copolymers (M29A29B9 and M62A52B32) are generated by using mannose (M), agmatine (A), and butyl (B) derivatives to target CD206, complex nucleic acids, and favor the endosomal escape, respectively. All glycopolycations efficiently complex pDNA at N/P ratios <5, protecting the pDNA from degradation in a physiological milieu. M58A45 and M62A52B32 complexed with plasmid encoding for antigenic ovalbumin (pOVA) trigger the immune activation of cultured dendritic cells, which present the SIINFEKL antigenic peptide via specific major histocompatibility complex-I. Importantly, administration of M58A45/pOVA elicits SIINFEKL-specific T-cell response in C56BL/6 mice bearing the melanoma tumor model B16-OVA, well in line with a reduction in tumor growth. These results qualify mannosylation as an efficient strategy to target immune cells in cancer vaccination and emphasize the potential of these glycopolycations as effective delivery vehicles for nucleic acids.

Viral Nanoparticles: Cancer Vaccines and Immune Modulators.

In the last decades, viruses have gained great interest in the field of immuno-oncology (I-O) for their ability of interacting both with the immune system and the tumour microenvironment. Those pathogens have naturally evolved and been evolutionary to specifically infect hosts, replicate, deliver their genome, and spread. These properties, initially considered a disadvantage, have been investigated and edited to turn viruses into precious allies for molecular biology serving as gene therapy vectors, adjuvants for the immune system, drug cargos, and, lately, anticancer therapeutics. As anticancer drug, one interesting option is viral engineering. Modification of either the viral genome or the outer shell of viruses can change infectivity and tissue targeting and add new functions to the viral particle. Remarkably, in the field of cancer virotherapy, scientists realized that a specific viral genomic depletion would turn the normal tropism of viruses to conditionally replicate in cancer cells only. This category of viruses, named 'Oncolytic viruses', have been investigated and used for cancer treatment in the past decades resulting in the approval of the first oncolytic virus, a herpes simplex virus expressing a stimulating factor, named T-Vec, in 2015. As such, oncolytic viruses achieved positive outcome but still are not able to completely eradicate the disease. This has brought the scientific community to edit those agents, adding to their ability to directly lysate cancer cells, few modifications to mainly boost their interaction with the immune system. Viruses experienced then a renaissance not only as infecting agent but as nanoparticle and cancer vaccines too. These strategies bring new life to the concept of using viruses as viral particles for therapeutic applications.

Oncolytic Adenoviruses for Cancer Therapy.

Many immuno-therapeutic strategies are currently being developed to fight cancer. In this scenario, oncolytic adenoviruses (Onc.Ads) have an interesting role for their peculiar tumor selectivity, safety, and transgene-delivery capability. The major strength of the Onc.Ads is the extraordinary immunogenicity that leads to a strong T-cell response, which, together with the possibility of the delivery of a therapeutic transgene, could be more effective than current strategies. In this review, we travel in the adenovirus (Ads) and Onc.Ads world, focusing on a variety of strategies that can enhance Onc.Ads antitumoral efficacy, passing through tumor microenvironment modulation. Onc.Ads-based therapeutic strategies constitute additional weapons in the fight against cancer and appear to potentiate conventional and immune checkpoint inhibitors (ICIs)-based therapies leading to a promising scenario.

Tumor Suppressor Role of hsa-miR-193a-3p and -5p in Cutaneous Melanoma.

BACKGROUND: Remarkable deregulation of several microRNAs (miRNAs) is demonstrated in cutaneous melanoma. hsa-miR-193a-3p is reported to be under-expressed in tissues and in plasma of melanoma patients, but the role of both miR-193a arms in melanoma is not known yet. METHODS: After observing the reduced levels of miR-193a arms in plasma exosomes of melanoma patients, the effects of hsa-miR-193a-3p and -5p transfection in cutaneous melanoma cell lines are investigated. RESULTS: In melanoma cell lines A375, 501Mel, and MeWo, the ectopic over-expression of miR-193a arms significantly reduced cell viability as well as the expression of genes involved in proliferation (ERBB2, KRAS, PIK3R3, and MTOR) and apoptosis (MCL1 and NUSAP1). These functional features were accompanied by a significant downregulation of Akt and Erk pathways and a strong increase in the apoptotic process. Since in silico databases revealed TROY, an orphan member of the tumor necrosis receptor family, as a potential direct target of miR-193a-5p, this possibility was investigated using the luciferase assay and excluded by our results. CONCLUSIONS: Our results underline a relevant role of miR-193a, both -3p and -5p, as tumor suppressors clarifying the intracellular mechanisms involved and suggesting that their ectopic over-expression could represent a novel treatment for cutaneous melanoma patients.

Helper-dependent adenovirus-mediated gene transfer of a secreted LDL receptor/transferrin chimeric protein reduces aortic atherosclerosis in LDL receptor-deficient mice.

Familial hypercholesterolemia (FH) is a genetic hyperlipidemia characterized by elevated concentrations of plasma LDL cholesterol. Statins are not always effective for the treatment of FH patients; unresponsive patients have poor prognosis and rely on LDL apheresis. In the past, we developed safe and effective gene therapy strategies for the expression of anti-atherogenic proteins using PEGylated helper-dependent adenoviral (HD-Ad) vectors. We recently developed a HD-Ad vector for the expression of the soluble form of the extracellular portion of the human LDL receptor (LDLR) fused with a rabbit transferrin dimer (LDLR-TF). We evaluated the efficacy of the LDLR-TF chimeric protein  in CHOLDLA7, a cell line lacking LDLR expression, restoring the ability to uptake LDL. Subsequently, we administered intravenously 1 × 10E13 vp/kg of this vector in LDLR-deficient mice and observed amelioration of lipid profile and reduction of aortic atherosclerosis. Finally, we studied LDL distribution after HD-Ad vector-mediated expression of LDLR-TF in LDLR-deficient mice and found LDL accumulation in liver, and in heart and intestine. These results support the possibility of lowering LDL-C levels and reducing aortic atherosclerosis using a secreted therapeutic transgene; the present strategy potentially can be modified and adapted to non-systemic gene transfer with expression of the secreted chimeric protein in muscle or other tissues. Intramuscular or local administration strategies could improve the safety profile of this strategy and facilitate applicability.

Peptide Nucleic Acid-Functionalized Adenoviral Vectors Targeting G-Quadruplexes in the P1 Promoter of Bcl-2 Proto-Oncogene: A New Tool for Gene Modulation in Anticancer Therapy.

The B-cell lymphoma 2 (Bcl-2) gene encodes for an antiapoptotic protein associated with the onset of many human tumors. Several oligonucleotides (ONs) and ON analogues are under study as potential tools to counteract the Bcl-2 expression. Among these are Peptide Nucleic Acids (PNAs). The absence of charges on PNA backbones allows the formation of PNA/DNA complexes provided with higher stability than the corresponding natural DNA/DNA counterparts. To date, the use of PNAs in antigene or antisense strategies is strongly limited by their inability to efficiently cross the cellular membranes. With the aim of downregulating the expression of Bcl-2, we propose here a novel antigene approach which uses oncolytic adenoviral vectors (OAds) as a new cancer cell-targeted PNA delivery system. The ability of oncolytic Ad5D24 vectors to selectively infect and kill cancer cells was exploited to transfect with high efficiency and selectivity a short cytosine-rich PNA complementary to the longest loop of the main G-quadruplex formed by the 23-base-long bcl2midG4 sequence located 52-30 bp upstream of the P1 promoter of Bcl-2 gene. Physico-chemical and biological investigations confirmed the ability of the PNA-conjugated Ad5D24 vectors to load and transfect their PNA cargo into human A549 and MDA-MB-436 cancer cell lines, as well as the synergistic (OAd+PNA) cytotoxic effect against the same cell lines. This approach holds promise for safer chemotherapy because of reduced toxicity to healthy tissues and organs.

Personalized Cancer Vaccine Platform for Clinically Relevant Oncolytic Enveloped Viruses.

The approval of the first oncolytic virus for the treatment of metastatic melanoma and the compiling evidence that the use of oncolytic viruses can enhance cancer immunotherapies targeted against various immune checkpoint proteins has attracted great interest in the field of cancer virotherapy. We have developed a novel platform for clinically relevant enveloped viruses that can direct the virus-induced immune response against tumor antigens. By physically attaching tumor-specific peptides onto the viral envelope of vaccinia virus and herpes simplex virus 1 (HSV-1), we were able to induce a strong T cell-specific immune response toward these tumor antigens. These therapeutic peptides could be attached onto the viral envelope by using a cell-penetrating peptide sequence derived from human immunodeficiency virus Tat N-terminally fused to the tumor-specific peptides or, alternatively, therapeutic peptides could be conjugated with cholesterol for the attachment of the peptides onto the viral envelope. We used two mouse models of melanoma termed B16.OVA and B16-F10 for testing the efficacy of OVA SIINFEKL-peptide-coated viruses and gp100-Trp2-peptide-coated viruses, respectively, and show that by coating the viral envelope with therapeutic peptides, the anti-tumor immunity and the number of tumor-specific CD8+ T cells in the tumor microenvironment can be significantly enhanced.

Optimization of Early Steps in Oncolytic Adenovirus ONCOS-401 Production in T-175 and HYPERFlasks.

Oncolytic adenoviruses can trigger lysis of tumor cells, induce an antitumor immune response, bypass classical chemotherapeutic resistance strategies of tumors, and provide opportunities for combination strategies. A major challenge is the development of scalable production methods for viral seed stocks and sufficient quantities of clinical grade viruses. Because of promising clinical signals in a compassionate use program (Advanced Therapy Access Program) which supported further development, we chose the oncolytic adenovirus ONCOS-401 as a testbed for a new approach to scale up. We found that the best viral production conditions in both T-175 flasks and HYPERFlasks included A549 cells grown to 220,000 cells/cm² (80% confluency), with ONCOS-401 infection at 30 multiplicity of infection (MOI), and an incubation period of 66 h. The Lysis A harvesting method with benzonase provided the highest viral yield from both T-175 and HYPERFlasks (10,887 ± 100 and 14,559 ± 802 infectious viral particles/cell, respectively). T-175 flasks and HYPERFlasks produced up to 2.1 × 108 ± 0.2 and 1.75 × 108 ± 0.08 infectious particles of ONCOS-401 per cm² of surface area, respectively. Our findings suggest a suitable stepwise process that can be applied to optimizing the initial production of other oncolytic viruses.

Antitumor-specific T-cell responses induced by oncolytic adenovirus ONCOS-102 (AdV5/3-D24-GM-CSF) in peritoneal mesothelioma mouse model.

Oncolytic adenoviral immunotherapy activates the innate immune system with subsequent induction of adaptive tumor-specific immune responses to fight cancer. Hence, oncolytic viruses do not only eradicate cancer cells by direct lysis, but also generate antitumor immune response, allowing for long-lasting cancer control and tumor reduction. Their therapeutic effect can be further enhanced by arming the oncolytic adenovirus with costimulatory transgenes and/or coadministration with other antitumor therapies. ONCOS-102 has already been found to be well tolerated and efficacious against some types of treatment-refractory tumors, including mesothelin-positive ovarian cancer (NCT01598129). It induced local and systemic CD8+ T-cell immunity and upregulated programmed death ligand 1. These results strongly advocate the use of ONCOS-102 in combination with other therapeutic strategies in advanced and refractory tumors, especially those expressing the mesothelin antigen. The in vivo work presented herein describes the ability of the oncolytic adenovirus ONCOS-102 to induce mesothelin-specific T-cells after the administration of the virus in bagg albino (BALB/c) mice with mesothelin-positive tumors. We also demonstrate the effectiveness of the interferon-γ the enzyme-linked immunospot (ELISPOT) assay to detect the induction of T-cells recognizing mesothelin, hexon, and E1A antigens in ONCOS-102-treated mesothelioma-bearing BALB/c mice. Thus, the ELISPOT assay could be useful to monitor the progress of therapy with ONCOS-102.

Chronic Activation of Innate Immunity Correlates With Poor Prognosis in Cancer Patients Treated With Oncolytic Adenovirus.

Despite many clinical trials conducted with oncolytic viruses, the exact tumor-level mechanisms affecting therapeutic efficacy have not been established. Currently there are no biomarkers available that would predict the clinical outcome to any oncolytic virus. To assess the baseline immunological phenotype and find potential prognostic biomarkers, we monitored mRNA expression levels in 31 tumor biopsy or fluid samples from 27 patients treated with oncolytic adenovirus. Additionally, protein expression was studied from 19 biopsies using immunohistochemical staining. We found highly significant changes in several signaling pathways and genes associated with immune responses, such as B-cell receptor signaling (P < 0.001), granulocyte macrophage colony-stimulating factor (GM-CSF) signaling (P < 0.001), and leukocyte extravasation signaling (P < 0.001), in patients surviving a shorter time than their controls. In immunohistochemical analysis, markers CD4 and CD163 were significantly elevated (P = 0.020 and P = 0.016 respectively), in patients with shorter than expected survival. Interestingly, T-cell exhaustion marker TIM-3 was also found to be significantly upregulated (P = 0.006) in patients with poor prognosis. Collectively, these data suggest that activation of several functions of the innate immunity before treatment is associated with inferior survival in patients treated with oncolytic adenovirus. Conversely, lack of chronic innate inflammation at baseline may predict improved treatment outcome, as suggested by good overall prognosis.

Synergistic anti-tumor efficacy of immunogenic adenovirus ONCOS-102 (Ad5/3-D24-GM-CSF) and standard of care chemotherapy in preclinical mesothelioma model.

Malignant mesothelioma (MM) is a rare cancer type caused mainly by asbestos exposure. The median overall survival time of a mesothelioma cancer patient is less than 1-year from diagnosis. Currently there are no curative treatment modalities for malignant mesothelioma, however treatments such as surgery, chemotherapy and radiotherapy can help to improve patient prognosis and increase life expectancy. Pemetrexed-Cisplatin is the only standard of care (SoC) chemotherapy for malignant mesothelioma, but the median PFS/OS (progression-free survival/overall survival) from the initiation of treatment is only up to 12 months. Therefore, new treatment strategies against malignant mesothelioma are in high demand. ONCOS-102 is a dual targeting, chimeric oncolytic adenovirus, coding for human GM-CSF. The safety and immune activating properties of ONCOS-102 have already been assessed in phase 1 study (NCT01598129). In this preclinical study, we evaluated the antineoplastic activity of combination treatment with SoC chemotherapy (Pemetrexed, Cisplatin, Carboplatin) and ONCOS-102 in xenograft BALB/c model of human malignant mesothelioma. We demonstrated that ONCOS-102 is able to induce immunogenic cell death of human mesothelioma cell lines in vitro and showed anti-tumor activity in the treatment of refractory H226 malignant pleural mesothelioma (MPM) xenograft model. While chemotherapy alone showed no anti-tumor activity in the mesothelioma mouse model, ONCOS-102 was able to slow down tumor growth. Interestingly, a synergistic anti-tumor effect was seen when ONCOS-102 was combined with chemotherapy regimens. These findings give a rationale for the clinical testing of ONCOS-102 in combination with first-line chemotherapy in patients suffering from malignant mesothelioma.

Oncolytic adenovirus and doxorubicin-based chemotherapy results in synergistic antitumor activity against soft-tissue sarcoma.

Despite originating from several different tissues, soft-tissue sarcomas (STS) are often grouped together as they share mesenchymal origin and treatment guidelines. Also, with some exceptions, a common denominator is that when the tumor cannot be cured with surgery, the efficacy of current therapies is poor and new treatment modalities are thus needed. We have studied the combination of a capsid-modified oncolytic adenovirus CGTG-102 (Ad5/3-D24-GMCSF) with doxorubicin, with or without ifosfamide, the preferred first-line chemotherapeutic options for most types of STS. We show that CGTG-102 and doxorubicin plus ifosfamide together are able to increase cell killing of Syrian hamster STS cells over single agents, as well as upregulate immunogenic cell death markers. When tested in vivo against established STS tumors in fully immunocompetent Syrian hamsters, the combination was highly effective. CGTG-102 and doxorubicin (without ifosfamide) resulted in synergistic antitumor efficacy against human STS xenografts in comparison with single agent treatments. Doxorubicin increased adenoviral replication in human and hamster STS cells, potentially contributing to the observed therapeutic synergy. In conclusion, the preclinical data generated here support clinical translation of the combination of CGTG-102 and doxorubicin, or doxorubicin plus ifosfamide, for the treatment of STS, and provide clues on the mechanisms of synergy.

GMCSF-armed vaccinia virus induces an antitumor immune response.

Oncolytic Western Reserve strain vaccinia virus selective for epidermal growth factor receptor pathway mutations and tumor-associated hypermetabolism was armed with human granulocyte-macrophage colony-stimulating factor (GMCSF) and a tdTomato fluorophore. As the assessment of immunological responses to human transgenes is challenging in the most commonly used animal models, we used immunocompetent Syrian golden hamsters, known to be sensitive to human GMCSF and semipermissive to vaccinia virus. Efficacy was initially tested in vitro on various human and hamster cell lines and oncolytic potency of transgene-carrying viruses was similar to unarmed virus. The hGMCSF-encoding virus was able to completely eradicate subcutaneous pancreatic tumors in hamsters, and to fully protect the animals from subsequent rechallenge with the same tumor. Induction of specific antitumor immunity was also shown by ex vivo co-culture experiments with hamster splenocytes. In addition, histological examination revealed increased infiltration of neutrophils and macrophages in GMCSF-virus-treated tumors. These findings help clarify the mechanism of action of GMCSF-armed vaccinia viruses undergoing clinical trials.

Treatment of melanoma with a serotype 5/3 chimeric oncolytic adenovirus coding for GM-CSF: Results in vitro, in rodents and in humans.

Metastatic melanoma is refractory to irradiation and chemotherapy, but amenable to immunological approaches such as immune-checkpoint-inhibiting antibodies or adoptive cell therapies. Oncolytic virus replication is an immunogenic phenomenon, and viruses can be armed with immunostimulatory molecules. Therefore, oncolytic immuno-virotherapy of malignant melanoma is an appealing approach, which was recently validated by a positive phase 3 trial. We investigated the potency of oncolytic adenovirus Ad5/3-D24-GMCSF on a panel of melanoma cell lines and animal models, and summarized the melanoma-specific human data from the Advanced Therapy Access Program (ATAP). The virus effectively eradicated human melanoma cells in vitro and subcutaneous SK-MEL-28 melanoma xenografts in nude mice when combined with low-dose cyclophosphamide. Furthermore, virally-expressed granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulated the differentiation of human monocytes into macrophages. In contrast to human cells, RPMI 1846 hamster melanoma cells exhibited no response to oncolytic viruses and the chimeric 5/3 fiber failed to increase the efficacy of transduction, suggesting limited utility of the hamster model in the context of viruses with this capsid. In ATAP, treatments appeared safe and well-tolerated. Four out of nine melanoma patients treated were evaluable for possible therapy benefit with modified RECIST criteria: one patient had minor response, two had stable disease, and one had progressive disease. Two patients were alive at 559 and 2,149 days after treatment. Ad5/3-D24-GMCSF showed promising efficacy in preclinical studies and possible antitumor activity in melanoma patients refractory to other forms of therapy. This data supports continuing the clinical development of oncolytic adenoviruses for treatment of malignant melanoma.

Serotype chimeric oncolytic adenovirus coding for GM-CSF for treatment of sarcoma in rodents and humans.

Sarcomas are a relatively rare cancer, but often incurable at the late metastatic stage. Oncolytic immunotherapy has gained attention over the past years, and a wide range of oncolytic viruses have been delivered via intratumoral injection with positive safety and promising efficacy data. Here, we report preclinical and clinical results from treatment of sarcoma with oncolytic adenovirus Ad5/3-D24-GMCSF (CGTG-102). Ad5/3-D24-GMCSF is a serotype chimeric oncolytic adenovirus coding for human granulocyte-macrophage colony-stimulating factor (GM-CSF). The efficacy of Ad5/3-D24-GMCSF was evaluated on a panel of soft-tissue sarcoma (STS) cell lines and in two animal models. Sarcoma specific human data were also collected from the Advanced Therapy Access Program (ATAP), in preparation for further clinical development. Efficacy was seen in both in vitro and in vivo STS models. Fifteen patients with treatment-refractory STS (13/15) or primary bone sarcoma (2/15) were treated in ATAP, and treatments appeared safe and well-tolerated. A total of 12 radiological RECIST response evaluations were performed, and two cases of minor response, six cases of stable disease and four cases of progressive disease were detected in patients progressing prior to virus treatment. Overall, the median survival time post treatment was 170 days. One patient is still alive at 1,459 days post virus treatment. In summary, Ad5/3-D24-GMCSF appears promising for the treatment of advanced STS; a clinical trial for treatment of refractory injectable solid tumors including STS is ongoing.

Oncolytic adenovirus with temozolomide induces autophagy and antitumor immune responses in cancer patients.

Oncolytic adenoviruses and certain chemotherapeutics can induce autophagy and immunogenic cancer cell death. We hypothesized that the combination of oncolytic adenovirus with low-dose temozolomide (TMZ) is safe, effective, and capable of inducing antitumor immune responses. Metronomic low-dose cyclophosphamide (CP) was added to selectively reduce regulatory T-cells. Preclinically, combination therapy inhibited tumor growth, increased autophagy, and triggered immunogenic cell death as indicated by elevated calreticulin, adenosine triphosphate (ATP) release, and nuclear protein high-mobility group box-1 (HMGB1) secretion. A total of 41 combination treatments given to 17 chemotherapy-refractory cancer patients were well tolerated. We observed anti- and proinflammatory cytokine release, evidence of virus replication, and induction of neutralizing antibodies. Tumor cells showed increased autophagy post-treatment. Release of HMGB1 into serum--a possible indicator of immune response--increased in 60% of treatments, and seemed to correlate with tumor-specific T-cell responses, observed in 10/15 cases overall (P = 0.0833). Evidence of antitumor efficacy was seen in 67% of evaluable treatments with a trend for increased survival over matched controls treated with virus only. In summary, the combination of oncolytic adenovirus with low-dose TMZ and metronomic CP increased tumor cell autophagy, elicited antitumor immune responses, and showed promising safety and efficacy.