ONCOLYTIC VIROTHERAPY CONGRESS 2017 AGENDA
Tumor-Specific Immunogene Therapy Approach Using Transgene Bearing Variants of Oncolytic Adenovirus Enadenotucirev
Utilising the enadenotucirev virus as a vector system for the delivery of therapeutic transgenes to cancer cells.
Tumor cell, the DNA encoded transgenes are transcripted into mRNA which in turn is translated into proteins
T-SIGn virus turns the tumor cell into a “drug factory”. The result is localized delivery of biological anti-cancer therapeutics (with known or novel mechanisms) working to enhance the activity of enadenotucirev.
NG-348 is a virus that encodes for Membrane-integrated T-Cell Engagers (MiTEs), forcing tumor cells to express T-cell activating ligands on their cell surface.
Brian Champion - CSO -PsiOxus Therapeutic
Antibody-Mediated Delivery of Oncolytic Viruses to Tumours via Monocyte Carriage
Oncolytic virus (OV) therapy is emerging as a promising new approach for cancer treatment, with a rapid expansion in the number of clinical trials in recent years. Confidence in the field increased following FDA approval for the first agent in class, talimogenelaherparepvec (T-Vec, a Herpes Simplex virus encoding GM-CSF) to treat melanoma. FDA approval for T-Vec is for intra-tumoural delivery only and while this route ensures viral access to the tumour, it is technically challenging and limits treatment to readily accessible tumours. Systemic delivery is more broadly applicable in a clinical setting and more suitable for targeting visceral or widespread metastatic disease. Current dogma states that the presence of either pre-existing anti-viral neutralizing antibodies (NAb) in patients, or their development during viral therapy, are a barrier to systemic OV delivery making repeat systemic treatments unlikely to be effective. However, little convincing evidence supporting this notion exists. Our recent data suggests that, rather than having a detrimental effect, NAb may actually contribute to OV delivery to tumours under some conditions, thus enhancing viral dissemination and improving therapy.
We have found that reovirus forms complexes with antibodies present in patient serum and that following loading of these reovirus/antibody (reo/NAb) complexes onto monocytes, the virus can be delivered (‘handed off’) in an infectious form to tumour cell lines. The neutralizing antibody isotypes involved are IgG and IgA. Reo/NAb complexes associated with monocytes induced melanoma cell death, whereas free reo/NAb complexes were ineffective. Thus reovirus was fully neutralized in the reo/NAb complexes and unable to bind to andinfect melanoma cells directly but, when loaded onto monocyte carriers, became effective for tumour cell killing. This was not simply a result of the reovirus activating the monocytes to kill the tumours, because reo/NAb complexes containing UV-inactivated reovirus (which cannot infect tumour cells but does induce monocyte activation) did not promote tumour cell death. The mechanism by which this occurs is not fully elucidated but early data suggests uptake of the reo/NAb complexes involves Fc receptors. Infectious reovirus titres did not increase following loading of reo/NAb onto monocytes, suggesting that these cells are not highly permissive reovirus “replication factories”.Preliminary evidence suggests that monocytes may also be carriers for other OV/NAb complexes,as neutralized Coxsackievirus-A21 can also mediate melanoma cell death following loading onto monocytes. Finally, replicating reovirus can be retrieved from tumours in mice treated with intravenous ex vivo-generated reovirus/NAb complexes. These important findings have profound implications not only for the design of cancer therapy strategies but also for mechanistically defining routes of viral dissemination and the initiation of adaptive immune responses which modulate infection.
Dr Elizabeth Ilett - Research Fellow - University of Leeds
The Trojan Horse Cancer treatment: Targeting Oncolytic Viruses to Tumours using a Macrophage-based therapy
Dr Munitta Muthana - Lecturer - Department of Oncology & Metabolism - University of Sheffield
Systemic Oncolytic Viruses as Immunotherapy – from Laboratory to Clinic
Systemic Oncolytic Anti-cancer ‘Oncolytic’ viruses (OV), are naturally occurring or genetically modified viruses, which were first developed as direct cytotoxic agents. It is now becoming increasingly clear that they act predominantly by also stimulating anti-tumour immunity. The first such ‘immunovirotherapy’ agent, T-Vec (talimogene laherparepvec), a genetically modified herpes simplex virus encoding GM-CSF has now been approved in the US and in Europe, for direct intratumoural injection in melanoma. To address the question of whether OV can access tumours following intravenous injection, we have designed biological endpoint clinical studies and have shown that intravenous reovirus, delivered systemically prior to planned surgery, is detected in the resected specimen. The virus is protected from neutralizing antibodies in the circulation via protective cell carriage (‘hitchhiking’) by blood immune cells. Reovirus delivery upregulated interferon-regulated gene expression in resected tumours, as well as the PD-1/PD-L1 axis across both target tumour and immune effector cells. On taking this translational clinical data back to the laboratory we found, consistent with these findings, that addition of PD-1 blockade to reovirus enhanced systemic therapy in immunocompetent murine models. Hence OV represent a promising form of clinical immunotherapy, with the potential for systemic as well as local delivery. Moreover, they may switch tumours from being immunologically ‘cold’ to ‘hot’, and therefore prime the tumour microenvironment for effective combination therapy with immune checkpoint blockade.
Immune Cell Recruitment Following Intrapleural Administration of the Oncolytic HSV, Seprehvir in Mesothelioma Patient
Immunostimulatory Gene Therapy Using Oncolytic Adenoviruses
Cancer immunotherapy aims to activate the body’s own defense mechanisms to defeat cancer. CD40 is a pleiotropic receptor expressed in many cell types present in the tumor microenvironment such as myeloid cells, fibroblasts, endothelial cells and epithelial cells that all contribute to promote tumor progression and metastases. Activation of CD40 usually leads to the upregulation of cytokines and chemokines, which in immune cells promote potent Th1 cytokines and costimulatory molecules. In our studies in mice, dog and man adenovirus based CD40L gene therapy has shown promising anti-tumor responses. CD40 signaling can be potentiated with simultaneous Toll-like receptor and/or 4-1BBL signaling.
We have developed a novel oncolytic adenovirus (LOAd703) expressing both CD40L and 4-1BBL to optimize immune signaling in the tumor microenvironment.LOAd703 could efficientlyactivate immune cells including human monocyte-derived dendritic cells, T cells and NK cells. Further, LOAd703 infection changed the biology of fibroblast like stellate cells to reduce their production of TGFbeta and collagen type I. Infection of endothelial cells demonstrated that they upregulate receptors for lymphocyte attachment, enrollment and transmigration which can support infiltration of lymphocytes into the tumor. In addition, LOAd703 directly kill tumor cells via oncolysis while sparing normal cells sorted from healthy tissues. In vivo, LOAd703 eradicated established tumors in a pancreatic cancer model. Gemcitabine, current standard of care treatment for pancreatic cancer, could be combined with LOAd703 to induce tumor control also in large tumors. A Phase I/II trial is ongoing in which LOAd703 is used in combination with standard chemotherapy treatment (NCT02705196).
Angelica Loskog - CEO - Lokon
Viral Vector Engineering Approaches using Standard and CRISPR based Systems
The development of complex biologics requires equally complex DNA design and engineering strategies. Oxford Genetics has worked to create solutions for the engineering of both RNA and DNA based viruses for virotherapy applications, alongside algorithms to reduce the variability inherent in designing systems for protein expression. The size of many viral vector genomes prevents their easy manipulation using standard cloning approaches, deploying CRISPR-Cas9 based systems can significantly improve the rate of vector development and allow rapid virus engineering.
Engineering complex viruses for virotherapy applications
Standardisation of genetic platforms for the rapid analysis of exogenous sequences
Deploying CRISPR based approaches to virus engineering
Engineering of virus packaging cell lines allows scalable manufacture of gene therapy modalities
Dr Ryan Cawood- CEO and Founder - Oxford Genetics
Oncolytic Coxsackie A21 as a Cancer Immunotherapy
Prof Hardev Pandha FRCP FRACP PhD FSB - Director, Surrey Cancer Research Institute, University of Surrey
Development of Novel Parvovirus Based Combination Therapies
Oncolytic viruses (OVs) are of growing interest as cancer therapeutics for their ability to kill tumour cells both directly by inducing oncolysis and indirectly by activating antitumour immune responses. Protoparvoviruses (PV) belong to the dozen of oncolytic viruses presently evaluated at both preclinical and clinical levels. In particular the rat parvovirus H-1PV attracts high attention as an anticancer agent, because it is not pathogenic for humans and possesses oncolytic and oncosuppressive properties demonstrated in a number of in vitro and in vivo models. This virus has the ability to induce multiple cell death pathways such as apoptosis, necrosis and cathepsin B-mediated cell death and to elicit strong anticancer immune responses. H-1 PV was recently tested in a monocentric phase I/IIa trial in 18 patients with recurrent glioblastoma, the most common and aggressive form of brain tumour in humans. Results show that virus treatment is safe, well tolerated and is associated with first evidenceof efficacy. However, further development is necessary to improve clinical outcome.Our goal is to improve the anticancer efficacy of H-1PV at the preclinical level and move most promising therapies into the clinic. To this end we are designing novel combination protocolsbased on H-1PV and other anticancer agents such as epigenetic modifiers, apoptosis activators and immune-checkpoint blockade. An overview of such strategies will be given with a look into the future.
Antonio Marchini - Principal Investigator- German Cancer Research Center
Targeting Prostate and Pancreatic Cancer with Oncolytic Adenoviral Mutants
Oncolyticadenoviral mutants have been evaluated in numerous clinical trials targeting solid cancers and reported to be safe, withdemonstrated enhancement of efficacy in conjunction with cytotoxic agents. Potent synergy has been established in preclinical models in combination with DNA-damaging apoptosis-inducing cytotoxic agents.
Recent progress in the clinical development of several oncolyticvirus species as multimodal cancer therapeutics demonstrates the effectiveness of these biological agents to reduce progression of late stage cancers that are resistant to all current therapies.Several oncolytic adenoviruses expressing cytotoxic transgenes, prodrug-converting enzymes and/or immunomodulatory factors have been developed with many mutants being evaluated in early phase clinical trials in combination with current therapeutics.
The presentation will focus on our preclinical studies:
Dr Gunnel Halldén - Reader in Cancer Gene Therapy -Barts Cancer Institute
Review of the Immune Activating and Clinical Properties of ONCOS-102
ONCOS-102is a double targeted, chimeric oncolytic adenovirus, coding for human GM-CSF. The use of ONCOS-102 as cancer immune activator aims to i) oncolyse tumor cells and ii) trigger a tumor-specific immune response that targets the patient’s unique tumor antigen repertoire.
We conducted a phase I study with ONCOS-102, in patients with solid tumors refractory to available treatments. The objectives of the study were to determine the optimal dose for further use and to assess the safety, tolerability and adverse event (AE) profile of ONCOS-102. Further, the response rate and overall survival were evaluated as well as preliminary evidence of disease control. As an exploratory endpoint, the effect of ONCOS 102 on biological correlates was examined.
The study was conducted using a classic 3 + 3 dose escalation study design involving 12 patients. Patients were repeatedly treated intratumorally with ONCOS-102 plus daily low-dose oral cyclophosphamide (CPO). Tumor response was evaluated with diagnostic positron emission tomography (PET) and computed tomography (CT). Tumor biopsies were collected at baseline and after treatment initiation for analysis of immunological correlates. Peripheral blood mononuclear cells (PBMCs) were collected at baseline and during the study to assess antigen specificity of CD8+ T cells by interferon gamma (IFNγ) ELISPOT.
ONCOS-102 is safe and well tolerated at the tested doses. All three examined doses may be used in further development. There was evidence of antitumor immunity and signals of clinical efficacy. Results indicate that ONCOS-102 may, in the future, provide clinical value as a treatment for solid tumors and to sensitize tumors to other immunotherapies by modulating a T cell positive phenotype to an initially T-cell negative tumor. Phase I/II studies in malignant pleural mesothelioma (NCT02879669), melanoma (NCT03003676) and in subjects with advanced peritoneal malignancies (NCT02963831)have just been started in Europe and USA.
Dr Lukasz KuryK - Senior Research Scientist - Targovax AS
A New Class of Cancer Immunotherapeutic Agents: Tumour-targeted Oncolytic Viruses--What have we learnt and where are we going?
Tumour-targeted oncolytic viruses (TOVs) have become a new class of cancer therapeutics as TOVs can kill cancer cells through multiple mechanisms of action, especially via virus-induced engagement of the immune response against tumour cells. TOVs have shown some promising clinical outcome, with having two TOVs approved as new drugs for cancer treatment. Although the clinical safety profile of the viruses is encouraging, the efficacy of the virus as monotherapy has been limited. Therefore, it is imperative to develop next generation of oncolytic viruses and strategies to improve the anti-cancer potency of these agents.
Vaccinia virus (VV) has several inherent features that make it particularly attractive for use as an oncolytic agent. In this talk, the speaker will first discuss how to choose VV strain to develop next generation of oncolytic VV. A novel tumour-targeted VV as an effective immunotherapeutic agent for treating established cancers and preventing cancer recurrence as well as metastasis after surgery will be demonstrated. The future of tumour-targeted oncolytic VV, especially how TOVs could potentially overcome the weaknesses of immune check point blockage therapy and CAR-T cell therapy in order to optimise immunotherapy and boost the immune system to maximise the therapeutic potential of treatment will be finally discussed.
Professor Yaohe Wang - Professor of Cancer Cell and Gene Therapy - Barts Cancer Institute
Epitope Identification and Clinical Immune Monitoring in Immune Oncology Programmes: Considerations and Opportunities to Ensure Success
Characterisation and monitoring of antigen-specific immune responses is a critical element of the clinical trial data package, providing mechanistic and functional insights into the performance of immunotherapies. This talk will explain the latest technologies to identify T cell epitopes (against tumour antigens and oncolytic viruses) as well as the implementation of tracking antigen-specific T cells.
Poxvirus – Based Oncolytic Immunotherapy: Clinical Development and Preclinical Studies
Poxviruses are powerful immunotherapeutics and tumor-targeting platforms, as demonstrated by decades of both preclinical and clinical results with the Vaccinia virus backbone.
Pexa-Vec (pexastimogenedevacirepvec, JX-594) is an oncolytic and immunotherapeutic vaccinia virus (Wyeth strain)which selectively replicates in and destroy cancer cells, accompanied by tumor vasculature disruption and anti-tumor immunity mediated by the expression of GM-CSF. A randomized Ph 2 dose-finding study with 3intratumoral (IT) liver injections ofPexa-Vec in first line advanced HCC showed an acceptable safety profile and a significant increase in overall survial (OS) in the highest dose group (Heo et al. 2013). A randomized open-label Ph 3 study conducted by Transgene’s partner SillaJen is ongoing comparing the efficacy and tolerability of Pexa-Vec plus sorafenib vs sorafenib in advanced first line HCC patients (NCT02562755). The primary endpoint is OS. An update of Transgene’s early stage clinical trials in various indications and in combination with checkpoint blockade will be presented.
TG6002 is an oncolytic vaccinia virus (Copenhagen strain) armed with Fcu1, a chimeric enzyme which locally activates the prodrug 5-FC into 5-Fu at the tumor replication site. This product has demonstrated remarkable preclinical efficacy in a large variety of tumors, and its safety profile has been improved thanks to a double mutation of the TK and RR genes. Preclinical studies have shown a strong contribution of the immune system in the mechanism of action. The clinical development of TG6002 is currently starting, with a planned Ph1/2a trial in glioblastomaby the intravenous (IV) route, and possibly gastrointestinal tumors.
The Transgene’s portfolio also includes new oncolytic vaccinia-based vectors containing different transgenes, for which preclinical results will be presented.For example, we recently expanded our portfolio of armed oVV by engineering a vector that targets anti-PD1 IgG expression into the tumor. Local concentration of virus-encoded antibody was ~10-50 times higher than the reference mAb, leading to significant improvement of survival in a sarcoma preclinical model. Such results announce the next-generation oVVs, combining immunogenic oncolysis with the capacity to deliver complex therapeutic modalities in the tumor micro-environment, notably to restore immunocompetence and to attract effector cells / express chemoattractants, by encoding a full range of molecular agents.
Hyaluronidase Expressing Oncolytic Adenoviruses
Tumour targeting upon intravenous administration and subsequent intratumoural virus dissemination are key features for successful oncolytic adenovirus therapy. Pre-existing neutralizing antibodies (Nabs) can be overcome by pre-selecting the patient population and treating only those patients with low antibody titre or by modifying the viral capsid to be able to treat patients at high Nabs titre. VCN-01 is a selective oncolytic adenovirus with hyaluronidase activity that has shown, in pre-clinical studies in the absence of Nabs, improved tumour targeting, enhanced intratumoural spreading of oncolytic adenovirus and high anti-tumour activity.VCN-01 has also shown sensitization to chemotherapy after systemic administration of VCN-01 and increased tumour-uptake of Gemcitabine (GE) compared to compared to control (PBS) or Abraxane (ABRX) /GE treatment in an orthotopic pancreatic cancer model. In patients, VCN-01 is able to reach tumours when administered to patients with low Nabs (≤ 1/320) at 3.3E+12 & 1E+13 viral particles/patient systemically and the viral dose correlates with VCN-01 levels in blood, with the virus being detected for over 3 weeks. VCN-01 is safe both alone and in combination ABRX/GE, with MTD at 1E+13vp/patient in monotherapy and at 3.3E+12vp/patient when combined with chemotherapy.
In order to treat patients with higher Nabs titre (≥1/320), we have inserted an albumin-binding domain (ABD) within VCN-01 capsid so that it binds to albumin and protects it from Nabs. This virus is called VCN-11, a hyaluronidase expressing oncolytic adenovirus that evades neutralizing antibodies. The neutralizing evasion capacity of the ABD-modified virus has been demonstrated in vitro and in vivo employing commercial antibodies and serum from patients. Long circulation kinetics has been demonstrated for the ABD-modified virus and increased tumour targeting in the presence of Nabs in vivo. VCN-11 has decreased liver targeting which makes it is less toxicthan VCN-01 measured by body weight loss, biochemical parameters and haematology profile. Preclinical studies show that the incorporation of the ABD domain into the virus makes it able to give significant anti-tumour activity regardless of previous immunity against Ad5WT.
Oncolytic Semliki Forest Virus for Treatment of Brain Cancer
Glioblastomamultiforme (GBM) is a rapidly growing form of brain cancer that is impossible to cure with the current standard therapies. It affects both adults and children. Various oncolytic viruses have been tested in the clinic, but without much therapeutic benefit. We have utilized the fact that SFV has a natural neurotropism and developed it for therapy of GBM. As SFV is a small positive-strand RNA virus replicating in the cytoplasm we introduced microRNA target sequences into its genome to control its replication capacity. We detargeted the virus from replicating in normal neurons and other healthy brain cell by using three central nervous system (CNS)-related mircoRNAsto create SFV4miRT. Systemic treatment with SFV4miRT has the capacity to cure about 30% of mice with orthotopic, syngenic high-gradeglioma in preclinical murine models. Because SFV4 is partly type-I interferon insensitive the SFV4miRT virus could kill also tumors cells with moderate secretion of type-I interferons. By using the newly established Human Glioblastoma Cell Culture (HGCC) resource (www.hgcc.se) we demonstrate that SFV4miRT could kill human glioblastoma cell cultures of all molecular subtypes (proneural, classical, mesenchymal,neural), which indicates the potential for its clinical translational.
Magnus Essand - Department of Immunology, Genetics and Pathology, Clinical Immunology - Uppsala Univesity