Viral Immunotherapy Research Articles

CTIM-15. RESULTS OF A PHASE IB TRIAL OF RECOMBINANT POLIO:RHINOVIRUS IMMUNOTHERAPY FOR RECURRENT PEDIATRIC HIGH GRADE GLIOMA

Abstract BACKGROUND Outcomes of recurrent pediatric high grade glioma (pHHG) are poor with a median overall survival (OS) of < 6 months. Viral immunotherapy such as the polio:rhinovirus chimera, PVSRIPO, is a novel treatment approach for recurrent pHHG. PVSRIPO is genetically engineered to prevent neurovirulence. In adults with recurrent glioblastoma treated with PVSRIPO, 21% survived > 36 months. The poliovirus receptor, CD155, is ubiquitously expressed in malignant pediatric brain tumors including pHHG. METHODS The primary objective of this Phase 1b clinical trial was to evaluate the safety and feasibility of PVSRIPO for recurrent pHGG. PVSRIPO was given at a single dose, 5x107 50% tissue-culture infectious dose (TCID50) administered by convection enhanced delivery (CED) to children with biopsy-confirmed recurrent pHHG between ≥ 1 and ≤ 5.5 in diameter. 3 mL of PVSRIPO was delivered at 0.5 mL/hr via a single catheter. RESULTS Eight patients were treated with PVSRIPO including 5 males and 3 females with a median age of 16.5 (range 9-19). Six patients had recurrent glioblastoma, 2 had recurrent anaplastic astrocytoma. The median number of previous recurrences prior to enrollment was 3.5 (range 1-5). Four patients received bevacizumab on-study for treatment-related peritumoral inflammation/edema. Six of 8 patients experienced 26 treatment related adverse events (AEs) possibly, probably, or definitely related to protocol treatment. There were no Grade 4 or 5 AEs. There were 3 Grade 3 AEs: 2 headaches and 1 seizure. There were no AEs related to biopsy or CED catheter insertion/removal. Median OS was 4.13 months (range 1.23-NA). One patient is currently alive at > 21 months. Monocyte and T cell inflammatory phenotypes and total CD4+ T cells were increased in peripheral blood after treatment. CONCLUSIONS CED of PVSPRIO is both safe and feasible for the treatment of recurrent pHHG. Histologic correlative results will also be presented.

Intravenous injection of a novel viral immunotherapy encoding human interleukin-7 in nonhuman primates is safe and increases absolute lymphocyte count

ABSTRACT Persistence of an immunosuppression, affecting both the innate and adaptive arms of the immune system, plays a role in sepsis patients’ morbidity and late mortality pointing to the need for broad and effective immune interventions. MVA-hIL-7-Fc is a non-replicative recombinant Modified Vaccinia virus Ankara encoding the human interleukin-7 fused to human IgG2 Fc fragment. We have shown in murine sepsis models the capacity of this new virotherapy to stimulate both arms of the immune system and increase survival. Herein, an exploratory study in nonhuman primates was performed following a single intravenous injection of the MVA-hIL-7-Fc used at the clinical dose to assess its safety and biological activities. Four cynomolgus macaques were followed for 3 weeks post-injection (p.i), without observed acute adverse reactions. Circulating hIL-7-Fc was detected during the first 3–5 days p.i with a detection peaking at 12 h p.i. IL-7 receptor engagement and downstream signal transduction were detected in T cells demonstrating functionality of the expressed IL-7. Expansion of blood lymphocytes, mainly CD4 and CD8 naïve and central memory T cells, was observed on day 7 p.i. together with a transient increase of Ki67 expression on T lymphocytes. In addition, we observed an increase in circulating B and NK cells as well as monocytes were albeit with different kinetics and levels. This study indicates that a vectorized IL-7-Fc, injected by intravenous route at a relevant clinical dose in a large animal model, is active without adverse reactions supporting the clinical development of this novel virotherapy for treatment of sepsis patients.

Counteracting Immunosuppression in the Tumor Microenvironment by Oncolytic Newcastle Disease Virus and Cellular Immunotherapy.

An apparent paradox exists between the evidence for spontaneous systemic T cell- mediated anti-tumor immune responses in cancer patients, observed particularly in their bone marrow, and local tumor growth in the periphery. This phenomenon, known as "concomitant immunity" suggests that the local tumor and its tumor microenvironment (TME) prevent systemic antitumor immunity to become effective. Oncolytic Newcastle disease virus (NDV), an agent with inherent anti-neoplastic and immune stimulatory properties, is capable of breaking therapy resistance and immunosuppression. This review updates latest information about immunosuppression by the TME and discusses mechanisms of how oncolytic viruses, in particular NDV, and cellular immunotherapy can counteract the immunosuppressive effect of the TME. With regard to cellular immunotherapy, the review presents pre-clinical studies of post-operative active-specific immunotherapy and of adoptive T cell-mediated therapy in immunocompetent mice. Memory T cell (MTC) transfer in tumor challenged T cell-deficient nu/nu mice demonstrates longevity and functionality of these cells. Graft-versus-leukemia (GvL) studies in mice demonstrate complete remission of late-stage disease including metastases and cachexia. T cell based immunotherapy studies with human cells in human tumor xenotransplanted NOD/SCID mice demonstrate superiority of bone marrow-derived as compared to blood-derived MTCs. Results from clinical studies presented include vaccination studies using two different types of NDV-modified cancer vaccine and a pilot adoptive T-cell mediated therapy study using re-activated bone marrow-derived cancer-reactive MTCs. As an example for what can be expected from clinical immunotherapy against tumors with an immunosuppressive TME, results from vaccination studies are presented from the aggressive brain tumor glioblastoma multiforme. The last decades of basic research in virology, oncology and immunology can be considered as a success story. Based on discoveries of these research areas, translational research and clinical studies have changed the way of treatment of cancer by introducing and including immunotherapy.

Immunovirotherapy: The role of antibody based therapeutics combination with oncolytic viruses.

Despite the fact that the new drugs and targeted therapies have been approved for cancer therapy during the past 30 years, the majority of cancer types are still remain challenging to be treated. Due to the tumor heterogeneity, immune system evasion and the complex interaction between the tumor microenvironment and immune cells, the great majority of malignancies need multimodal therapy. Unfortunately, tumors frequently develop treatment resistance, so it is important to have a variety of therapeutic choices available for the treatment of neoplastic diseases. Immunotherapy has lately shown clinical responses in malignancies with unfavorable outcomes. Oncolytic virus (OV) immunotherapy is a cancer treatment strategy that employs naturally occurring or genetically-modified viruses that multiply preferentially within cancer cells. OVs have the ability to not only induce oncolysis but also activate cells of the immune system, which in turn activates innate and adaptive anticancer responses. Despite the fact that OVs were translated into clinical trials, with T-VECs receiving FDA approval for melanoma, their use in fighting cancer faced some challenges, including off-target side effects, immune system clearance, non-specific uptake, and intratumoral spread of OVs in solid tumors. Although various strategies have been used to overcome the challenges, these strategies have not provided promising outcomes in monotherapy with OVs. In this situation, it is increasingly common to use rational combinations of immunotherapies to improve patient benefit. With the development of other aspects of cancer immunotherapy strategies, combinational therapy has been proposed to improve the anti-tumor activities of OVs. In this regard, OVs were combined with other biotherapeutic platforms, including various forms of antibodies, nanobodies, chimeric antigen receptor (CAR) T cells, and dendritic cells, to reduce the side effects of OVs and enhance their efficacy. This article reviews the promising outcomes of OVs in cancer therapy, the challenges OVs face and solutions, and their combination with other biotherapeutic agents.

SARS CoV-2 infections in animals, two years into the pandemic.

In December 2019, several cases of pneumonia caused by a novel coronavirus, later identified as SARS-CoV-2, were detected in the Chinese city of Wuhan. Due to its rapid worldwide spread, on 11 March 2020 the World Health Organization declared a pandemic state. Since this new virus is genetically similar to the coronaviruses of bats, SARS-CoV-2 was hypothesized to have a zoonotic origin. Within a year of the appearance of SARS-CoV-2, several cases of infection were also reported in animals, suggesting human-to-animal and animal-to-animal transmission among mammals. Natural infection has been found in companion animals as well as captive animals such as lions, tigers, and gorillas. Among farm animals, so far, minks have been found to be susceptible to SARS-CoV-2 infection, whereas not all the relevant studies agree on the susceptibility of pigs. Experimental infections have documented the susceptibility to SARS-CoV-2 of further animal species, including mice, hamsters, cats, dogs, ferrets, raccoon dogs, cattle, and non-human primates. Experimental infections have proven crucial for clarifying the role of animals in transmission and developing models for viral pathogenesis and immunotherapy. On the whole, this review aims to update and critically revise the current information on natural and experimental SARS-CoV-2 infections in animals.

Development of intravenously administered synthetic RNA virus immunotherapy for the treatment of cancer

The therapeutic effectiveness of oncolytic viruses (OVs) delivered intravenously is limited by the development of neutralizing antibody responses against the virus. To circumvent this limitation and to enable repeated systemic administration of OVs, here we develop Synthetic RNA viruses consisting of a viral RNA genome (vRNA) formulated within lipid nanoparticles. For two Synthetic RNA virus drug candidates, Seneca Valley virus (SVV) and Coxsackievirus A21, we demonstrate vRNA delivery and replication, virus assembly, spread and lysis of tumor cells leading to potent anti-tumor efficacy, even in the presence of OV neutralizing antibodies in the bloodstream. Synthetic-SVV replication in tumors promotes immune cell infiltration, remodeling of the tumor microenvironment, and enhances the activity of anti-PD-1 checkpoint inhibitor. In mouse and non-human primates, Synthetic-SVV is well tolerated reaching exposure well above the requirement for anti-tumor activity. Altogether, the Synthetic RNA virus platform provides an approach that enables repeat intravenous administration of viral immunotherapy.

Cytomegalovirus infection of brain tumors and CMV immunotherapy

Objective. The article presents the literature of the last ten years and the results of our own research on the importance of cytomegalovirus (CMV) in the development of brain tumors, especially glioblastoma and medulloblastoma. Two alternative views are discussed - the pros and cons of the role of the virus in the induction and stimulation of tumor growth.Materials and methods. 256 samples of biotic material of tissues of various brain tumors were studied. Among them are histologically diagnosed: in 123 cases glial tumors of various grade of malignancy, in 51 cases meningiomas, in 25 cases medulloblastomas, in 16 cases oligodendroastrocytomas of the second grade of malignancy, in 14 cases metastatic tumors. Tumor fragments were obtained from biopsy material 1.5-2.0 hours after surgical removal. To detect the presence of CMV in the tumor tissue real-time polymerase chain reaction (PCR) using "DNA sorb A and B" kits was performed, the company "Amplisens" (Russia), according to the manufacturer’s instructions and BioRal device (USA) with standard DNA detection kits of CMV "DNA Technology" (Russia). Cytological imprints on slides were also made from tumor tissue fragments, which were examined by indirect immunofluorescence method with monoclonal antibodies to CMV pP-65 protein using the "MonoScan CMV" kit.Results. The frequency of detection of CMV antigen or its DNA in brain tissue depends on the research method - the immunofluorescence method detects pP-65 antigen by monoclonal antibodies 2-2.5 times more often than the PCR method of CMV in tumor tissue. In the tissue of different histogenesis of brain tumors both the pP-65 antigen and CMV DNA are detected with different frequencies. CMV was most often detected in tumors of glial origin and medulloblastomas. No CMV DNA was detected in the peripheral blood of patients with brain tumors at the time of admission for examination and surgical treatment, indicating an earlier contamination of the tumor focus with this virus. Data on the mechanisms of CMV induction and stimulation of tumor growth by activating cell proliferation, including nerve stem cells, are presented. Works using specific antiviral therapy and CMV specific cell immunotherapy in the treatment of gliomas have been analyzed in detail.Conclusions. The paper concludes on the important clinical and prognostic value of determining CMV infection in brain tumors and indicates the need for CMV viral and cellular immunotherapy in the combined treatment of malignant brain tumors.

LBA39 Final 5-year results of the phase II, multicenter, randomized, open-label trial of talimogene laherparepvec (T-VEC) neoadjuvant treatment (Tx) plus surgery vs immediate surgery in patients (pts) with resectable stage IIIB-IVM1a melanoma (MEL)

The risk of recurrence after resection remains high for pts with advanced MEL. Neoadjuvant therapies before surgery shrink tumors, reduce recurrence risks, and potentially improve long-term outcomes. T-VEC, an intralesional oncolytic viral immunotherapy, selectively replicates in MELs and enhances the antitumor immune response. The primary analysis (NCT02211131) reported a 2-y recurrence-free survival (RFS) of 29.5% for T-VEC + surgery and 16.5% for surgery alone (overall HR 0.75; 80% CI 0.58-0.96) in pts with resectable stage IIIB-IVM1a MEL, persisting at 3 y (overall HR 0.74; 80% CI 0.57-0.95) (Dummer Nat Med 2021). Here, we report the final 5-y analysis. Pts with resectable stage IIIB-IVM1a MEL and ≥ 1 injectable cutaneous, subcutaneous, or nodal lesions were randomized 1:1 to six doses of neoadjuvant T-VEC, then surgery (Arm 1) or immediate surgery alone (Arm 2). T-VEC was administered at standard doses until surgery, no remaining injectable tumors, or intolerance. The investigator’s choice adjuvant Tx was allowed and used similarly in both arms. The final RFS was analyzed 5 y after randomization. As of May 30, 2022, the median follow-up for all 150 pts was 63.3 mo (range 0.1-86.8). For Arm 1 vs Arm 2, the 5-y KM estimates of RFS were 22.3% and 15.2% (HR 0.76, 80% CI 0.60-0.97), the 5-y KM estimates of EFS were 43.7% and 27.4% (HR 0.57, 80% CI 0.43-0.76), and the 5-y KM estimates of OS were 77.3% and 62.7% (HR 0.54, 80% CI 0.36-0.81). HRs for local RFS, regional RFS, and distant metastases-free survival (DMFS) were 0.82 (80% CI 0.64-1.06), 0.81 (80% CI 0.62-1.05), and 0.73 (80% CI 0.57-0.94), respectively. No new safety signals were detected. In the final readout of the largest randomized trial of neoadjuvant Tx in pts with resectable stage IIIB-IVM1a MEL, we report durable improvements in RFS, EFS, DMFS, and OS at 5 y with neoadjuvant T-VEC + surgery vs standard surgery. These results provide proof of concept that an intratumorally administered oncolytic agent can elicit a meaningful long-term systemic effect and support the use of neoadjuvant T-VEC + surgery in this pt population.

Binding of Coxsackievirus A21 procapsids to immobilized glutathione depends on cell culture conditions during infection

A prototype strain of Coxsackievirus A21 (CVA21) is under clinical evaluation as an oncolytic virus immunotherapy. To improve scalability of the manufacturing process, an affinity chromatography purification method was developed using immobilized glutathione resin that captured infectious CVA21 virions from cell culture harvests with high recovery and impurity clearance. Unexpectedly, the binding of empty CVA21 procapsids depended on production cell culture conditions during infection including temperature, presence of serum in the media, and production cell line. At 37 °C and 2% serum during infection, procapsids flowed-through while infectious virions bound and were recovered at >95% yield in the chromatography elution. However, at sub-physiological temperature or after removal of serum at infection, both procapsids and mature virions bound and co-eluted from the immobilized glutathione ligand. This work may improve the understanding of CVA21 capsid assembly and presents an efficient purification method that may be applied to picornaviruses that interact with intracellular GSH.

Charge-based interactions through peptide position 4 drive diversity of antigen presentation by human leukocyte antigen class I molecules.

Human leukocyte antigen class I (HLA-I) molecules bind and present peptides at the cell surface to facilitate the induction of appropriate CD8+ T cell-mediated immune responses to pathogen- and self-derived proteins. The HLA-I peptide-binding cleft contains dominant anchor sites in the B and F pockets that interact primarily with amino acids at peptide position 2 and the C-terminus, respectively. Nonpocket peptide–HLA interactions also contribute to peptide binding and stability, but these secondary interactions are thought to be unique to individual HLA allotypes or to specific peptide antigens. Here, we show that two positively charged residues located near the top of peptide-binding cleft facilitate interactions with negatively charged residues at position 4 of presented peptides, which occur at elevated frequencies across most HLA-I allotypes. Loss of these interactions was shown to impair HLA-I/peptide binding and complex stability, as demonstrated by both in vitro and in silico experiments. Furthermore, mutation of these Arginine-65 (R65) and/or Lysine-66 (K66) residues in HLA-A*02:01 and A*24:02 significantly reduced HLA-I cell surface expression while also reducing the diversity of the presented peptide repertoire by up to 5-fold. The impact of the R65 mutation demonstrates that nonpocket HLA-I/peptide interactions can constitute anchor motifs that exert an unexpectedly broad influence on HLA-I-mediated antigen presentation. These findings provide fundamental insights into peptide antigen binding that could broadly inform epitope discovery in the context of viral vaccine development and cancer immunotherapy.

Abstract 383: ONCR-021 as a systemic intravenous synthetic RNA virus immunotherapy for the repeat treatment of cancer

Abstract Oncolytic viruses (OV) have shown great potential to improve clinical outcomes when dosed intratumorally, however, their therapeutic efficacy when intravenously administered is likely limited by the rapid emergence of neutralizing antibodies. To overcome this limitation, we developed Synthetic RNA viruses consisting of a replication competent viral genomic RNA (vRNA) encapsulated within a lipid nanoparticle (LNP) for IV administration. Upon dosing and delivery of this infectious RNA payload, the vRNA initiates viral replication and virus production in neoplastic cells leading to oncolysis and tumor destruction. This formulation enables repeat intravenous dosing of a replication competent oncolytic virotherapy even in presence of circulating neutralizing antibody to the virus. Here we present ONCR-021, an LNP formulation of Coxsackievirus A21 (CVA21) vRNA. ONCR-021 vRNA encodes a novel ICAM1-dependent strain of CVA21 that results in greater in vitro and in vivo oncolysis compared to the previously described CVA21 Kuykendall strain. ONCR-021 is broadly oncolytic in cancer cell lines in vitro and is intended for clinical development in NSCLC, RCC, and HCC based upon the viral tropism. IV-administration of ONCR-021 vRNA results in rapid initiation of viral replication, oncolysis, and potent anti-tumor efficacy, even in the presence of circulating CVA21 neutralizing antibodies. This efficacy is principally driven by CVA21 amplification in situ after delivery to tumor cells and we demonstrate viral replication, virion production and spread within the tumor after dosing. We also observe only modest and transient production of CVA21 in healthy tissues of transgenic mice expressing the CVA21 entry receptor human ICAM1. Consistent with these findings, high doses levels of ONCR-021 were well-tolerated in this model. Altogether, these preclinical data support the development of ONCR-021, a novel synthetic oncolytic virus designed to overcome the challenges of repeat intravenous administration of viral immunotherapy for the treatment of disseminated cancers. Citation Format: Jeffrey Bryant, Agnieszka Denslow, Jacqueline Hewett, Lingxin Cong, Ana De Almeida, Jennifer Lee, Judy Jacques, Sonia Feau, Daniel. Wambua, Adrienne Yanez, Pam Shou-Ping Wang, Jessica Deterling, Matthew Scott, Jason Auer, Brian B. Haines, Christophe Quéva, Lorena Lerner, Edward M. Kennedy. ONCR-021 as a systemic intravenous synthetic RNA virus immunotherapy for the repeat treatment of cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 383.

Abstract 3299: Development of ONCR-788, a synthetic oncolytic virus based on Seneca Valley virus for the treatment of neuroendocrine tumors

Abstract Oncolytic viruses (OVs) are an emerging therapeutic approach for the treatment of cancer. Clinical benefit has been demonstrated for intratumoral administration. Still, the therapeutic effectiveness of intravenous delivery has been limited by neutralizing antibody responses against the virus. To circumvent this limitation, we developed Synthetic RNA viruses, a novel approach for intravenous and repeated administration of OVs, consisting of a viral RNA genome (vRNA) formulated within lipid nanoparticles. Systemic administration of ONCR-788, the Synthetic RNA virus drug candidate encoding the vRNA of Seneca Valley virus (SVV), led to potent anti-tumor efficacy, even in the presence of OV neutralizing antibodies in the bloodstream. After a single intravenous administration of ONCR-788, we demonstrated vRNA delivery, viral replication, spread, and lysis of tumor cells. Robust anti-tumor efficacy was observed across diverse neuroendocrine tumor models, including tumor CDX and PDX xenografts, lung orthotopic, and GEMM-derived models. In a syngeneic model, ONCR-788 stimulated both tumor lysis and modulation of the tumor microenvironment. Enhanced T cell recruitment and activation, increased expression of PD-L1 on tumor cells and myeloid cells, and M2 to M1 macrophage conversion were observed. Combination of ONCR-788 with anti-PD-1 resulted in improved anti-tumor activity versus the monotherapy arms. Altogether, ONCR-788 provides an innovative approach that enables repeat intravenous administration of viral immunotherapy. Citation Format: Edward M. Kennedy, Agnieszka Denslow, Jacqueline Hewett, Lingxin Kong, Ana De Almeida, Jeffrey Bryant, Jennifer S. Lee, Judy Jacques, Sonia Feau, Hayes Hayes, Elizabeth L. McMichael, Daniel Wambua, Sanmit Adhikari, Jessica Deterling, Matthew Scott, Brian H. Haines, Mitchel H. Finer, Ted Ashburn, Christophe Quéva, Lorena Lerner. Development of ONCR-788, a synthetic oncolytic virus based on Seneca Valley virus for the treatment of neuroendocrine tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3299.

Distinguishing the pros and cons of metabolic reprogramming in oncolytic virus immunotherapy.

Oncolytic viruses (OVs) represent a class of cancer immunotherapies that rely on hijacking the host cell factory for replicative oncolysis and eliciting immune responses for tumor clearance. An increasing evidence suggests that the metabolic state of tumor cells and immune cells is a putative determinant of the efficacy of cancer immunotherapy. However, how therapeutic intervention with OVs affects metabolic fluxes within the tumor microenvironment (TME) remains poorly understood. Herein, we review the complexities of metabolic reprogramming involving the effects of viruses and their consequences on tumor cells and immune cells. We highlight the inherent drawback of oncolytic virotherapy, namely that treatment with OVs inevitably further exacerbates the depletion of nutrients and the accumulation of metabolic wastes in the TME, leading to a metabolic barrier to antitumor immune responses. We also describe targeted metabolic strategies that can be used to unlock the therapeutic potential of OVs.

Reverse-Phase Ultra-Performance Chromatography Method for Oncolytic Coxsackievirus Viral Protein Separation and Empty to Full Capsid Quantification.

Oncolytic virus immunotherapy is emerging as a novel therapeutic approach for cancer treatment. Immunotherapy clinical drug candidate V937 is currently in phase I/II clinical trials and consists of a proprietary formulation of Coxsackievirus A21 (CVA21), which specifically infects and lyses cells with overexpressed ICAM-1 receptors in a range of tumors. Mature Coxsackievirus virions, consisting of four structural virion proteins, (VPs) VP1, VP2, VP3, and VP4, and the RNA genome, are the only viral particles capable of being infectious. In addition to mature virions, empty procapsids with VPs, VP0, VP1, and VP3, and other virus particles are produced in V937 production cell culture. Viral protein VP0 is cleaved into VP2 and VP4 after RNA genome encapsidation to form mature virions. Clearance of viral particles containing VP0, and quantification of viral protein distribution are important in V937 downstream processing. Existing analytical methods for the characterization of viral proteins and particles may lack sensitivity or are low throughput. We developed a sensitive and robust reverse-phase ultra-performance chromatography method to separate, identify, and quantify all five CVA21 VPs. Quantification of virus capsid concentration and empty/full capsid ratio was achieved with good linearity, accuracy, and precision. ClinicalTrials.gov ID: NCT04521621 and NCT04152863.

Novel gene immunotherapy prevents Aquaporin-4 (AQP4) mediated neuroinflammation and demyelination in a mouse model of multiple sclerosis

Abstract Neuromyelitis optica (NMO) is an auto-inflammatory demyelinating disease that typically affects optic nerves and spinal cord that is characterized by the presence of serum aquaporin-4 immunoglobulin G antibodies (AQP4-IgG). NMO accounts for >45% of the demyelinating disease in Asians and warrants the development of a suitable therapy other than generalized immunosuppressants. It is thought that autoimmune activated AQP4-specific T cells disrupt the BBB and allow increased entry of AQP4-IgG and other immune effectors into tissues containing astrocytes expressing AQP4 in their membranes. Recently we have established an adeno-associated viral (AAV) gene immunotherapy that effectively prevents and reverses experimental autoimmune encephalomyelitis (EAE) via generation of suppressive antigen-specific regulatory T cells (Tregs). In this report, using a similar antigen-specific approach, we have demonstrated that AAV.AQP4 gene immunotherapy prevented the development of AQP4-mediated neuroinflammation and clinical neurological disability in almost 100% of C57BL/6J mice when AAV.AQP4 vector was administered to mice 2 weeks prior to immunization with an immunogenic epitope of AQP4. Moreover, in contrast to AAV.AQP4 treated mice which remained unremarkable, histological analysis of the spinal cord sections from untreated vehicle only mice showed multiple areas of significant focal inflammation within the spinal cord. Based on our clinical and pathological data, we’ve successfully demonstrated that our novel AAV.AQP4 gene immunotherapy can indeed suppress the induction of AQP4 mediated autoimmune disease. Further evaluation will determine if it can also treat preexisting disease.

Viral Pathogens in Oesophageal and Gastric Cancer.

Tumour virology was born with the discovery by Peyton Rous in 1911 of a filterable agent in chicken cellular extracts that caused neoplasia in healthy chickens. Universally, 20% of all human cancers have a viral aetiology. Viruses are involved at various stages of the carcinogenesis pathway, depending on the viral pathogen, and likely require co-factors. Multiple risk factors have been associated with oesophageal and gastric malignancy, including carcinogenic pathogens. These viruses and bacteria include human papillomavirus (HPV) [oesophageal cancer], Epstein–Barr virus (EBV) [proximal stomach cancer], and Helicobacter pylori (HP) [non-cardia stomach cancer]. Viruses such as EBV have been firmly established as causal for up to 10% of gastric cancers. HPV is associated with 13 to 35% of oesophageal adenocarcinoma but its role is unclear in oesophageal squamous cell carcinomas. The causal relationship between hepatitis B (HBV), cytomegalovirus (CMV), HPV, and John Cunningham (JCV) and gastric neoplasia remains indeterminate and warrants further study. The expression of viral antigens by human tumours offers preventive and therapeutic potential (including vaccination) and has already been harnessed with vaccines for HPV and HBV. Future goals include viral protein-based immunotherapy and monoclonal antibodies for the treatment of some of the subset of EBV and HPV-induced gastro-esophageal cancers.

Neoadjuvant in situ vaccination with cowpea mosaic virus as a novel therapy against canine inflammatory mammary cancer

BackgroundInflammatory mammary cancer (IMC), the counterpart of human inflammatory breast cancer (IBC), is the deadliest form of canine mammary tumors. IMC patients lack specific therapy and have poor outcomes. This...

Oncolytic Orf virus licenses NK cells via cDC1 to activate innate and adaptive antitumor mechanisms and extends survival in a murine model of late-stage ovarian cancer

BackgroundNovel therapies are needed to improve outcomes for women diagnosed with ovarian cancer. Oncolytic viruses are multifunctional immunotherapeutic biologics that preferentially infect cancer cells and stimulate inflammation with the potential...

Local Treatment of a Pediatric Osteosarcoma Model with a 4-1BBL Armed Oncolytic Adenovirus Results in an Antitumor Effect and Leads to Immune Memory.

Osteosarcoma is an aggressive bone tumor occurring primarily in pediatric patients. Despite years of intensive research, the outcomes of patients with metastatic disease or those who do not respond to therapy have remained poor and have not changed in the last 30 years. Oncolytic virotherapy is becoming a reality to treat local and metastatic tumors while maintaining a favorable safety profile. Delta-24-ACT is a replicative oncolytic adenovirus engineered to selectively target cancer cells and to potentiate immune responses through expression of the immune costimulatory ligand 4-1BB. This work aimed to assess the antisarcoma effect of Delta-24-ACT. MTS and replication assays were used to quantify the antitumor effects of Delta-24-ACT in vitro in osteosarcoma human and murine cell lines. Evaluation of the in vivo antitumor effect and immune response to Delta-24-ACT was performed in immunocompetent mice bearing the orthotopic K7M2 cell line. Immunophenotyping of the tumor microenvironment was characterized by immunohistochemistry and flow cytometry. In vitro, Delta-24-ACT killed osteosarcoma cells and triggered the production of danger signals. In vivo, local treatment with Delta-24-ACT led to antitumor effects against both the primary tumor and spontaneous metastases in a murine osteosarcoma model. Viral treatment was safe, with no noted toxicity. Delta-24-ACT significantly increased the median survival time of treated mice. Collectively, our data identify Delta-24-ACT administration as an effective and safe therapeutic strategy for patients with local and metastatic osteosarcoma. These results support clinical translation of this viral immunotherapy approach.

Immunotherapy to prevent progression on active surveillance study (IPASS): A phase II, randomized, double-blind, controlled trial of PROSTVAC in prostate cancer patients who are candidates for active surveillance.

249 Background: Immunotherapy could potentially prevent disease progression for early-stage prostate cancer. In this randomized Phase 2 clinical trial, we evaluated the clinical effects of PROSTVAC, a vaccinia/fowlpox viral vector-based immunotherapy that contains PSA and three T-cell costimulatory molecules, in patients with localized prostate cancer. Methods:154 patients with clinically localized, low- or favorable intermediate-risk prostate cancer active surveillance were randomized (2:1) to receive 7 doses of subcutaneous PROSTVAC or placebo (empty fowlpox vector) over 140 days. Post-intervention prostate biopsy was performed 7-14 days after the last dose. Participants were followed for 6 months post-treatment. The primary outcome was change from baseline to post-vaccination in CD4 and CD8 T cell infiltration in biopsy tumor tissue. Secondary outcomes included changes in prostate biopsy Gleason grade (Grade Group) and serum PSA. Results: There were no differences in CD4 and CD8 densities (count of cells/mm2) in post-treatment biopsy tumor tissue between groups ( p = 0.63 and p = 0.75, respectively). Compared to placebo, patients who received PROSTVAC were less likely to demonstrate upgrading at follow-up biopsy, but this difference did not attain significance (22% vs. 40%, p= 0.08). There was no difference in the change of PSA from baseline to 6 months post-treatment between arms ( p= 0.30). Conclusions: In this first-of-kind trial of immunotherapy for localized prostate cancer, PROSTVAC was well tolerated but did not elicit significant prostate tissue T-cell responses compared to placebo. The favorable post-treatment biopsy grade findings in PROSTVAC patients merit further evaluation and longer-term clinical follow-up. Clinical trial information: NCT02326805.