381 Intratumoral oncolytic virus V937 plus ipilimumab in patients with advanced melanoma: the phase 1b MITCI study

BackgroundIntratumoral administration of V937, a bioselected genetically unmodified Coxsackievirus A21, has shown antitumor activity both as a monotherapy and in combination with the anti–PD-1 antibody pembrolizumab.1–3 V937 induces lytic tumor cell infection and upregulation of members of immune checkpoint pathways.2 We present the results from the phase 1b MITCI study that evaluated V937 plus ipilimumab for advanced melanoma.MethodsEligible patients had unresectable or metastatic stage IIIB/C or IV melanoma amenable to intratumoral injection. Patients received intratumoral V937 3×108 TCID50 on days 1, 3, 5, 8, and 22, then Q3W for 14 more injections plus intravenous ipilimumab 3 mg/kg Q3W administered 4 times starting on day 22. Imaging was done Q6W beginning at day 106; response was assessed per immune-related response criteria (irRC). The primary endpoints were safety and ORR in the overall population and in patients whose disease progressed on prior anti–PD-1 therapy.Results50 patients were enrolled and received ≥1 dose of study treatment. At data cutoff (February 21, 2020), all had discontinued the study and study therapy. Median (range) age was 64.5 (28–88) years. Fourteen patients (28%) had stage III disease. Forty patients (80%) had received prior systemic treatment, 33 of whom had received anti–PD-1 therapy. The median number of cycles of ipilimumab was 4 (range, 1–4), and the number of intratumoral injections of V937 was 9 (range, 5–19). Among the 94% of patients who had ≥1 treatment-related AE, 14% had grade 3/4 treatment-related AEs, none of which were considered related to V937. The most common grade 3/4 treatment-related AEs were dehydration, diarrhea, and hepatotoxicity (4% each). No grade 5 treatment-related AEs occurred. The most common treatment-related AEs were pruritus (50%), fatigue (44%), diarrhea (32%), and nausea (22%). Efficacy outcomes for the overall population and by prior anti-PD-1 therapy use are presented in table 1. Tumor regression was observed in injected and noninjected lesions.Abstract 381 Table 1ConclusionsV937 plus ipilimumab was safe and the toxicities were manageable and consistent with that anticipated for the individual treatment components. ORR was robust and significantly higher than anticipated with ipilimumab monotherapy, including in patients who had received prior anti–PD-1 therapy. Most responses were durable (≥26 weeks), and responses seen in noninjected metastases provided evidence of probable systemic immune activation. The combination of V937 plus ipilimumab warrants further investigation in a larger trial in patients with advanced melanoma.AcknowledgementsMedical writing assistance was provided by Kathleen Estes, PhD, of ICON plc (North Wales, PA, USA), funded by Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA.Trial RegistrationNCT02307149ReferencesPandha H, Harrington K, Ralph C, Melcher A, Gupta S, Akerley W, et al. Abstract CT115: phase 1b KEYNOTE 200 (STORM study): a study of an intravenously delivered oncolytic virus, coxsackievirus A21 in combination with pembrolizumab in advanced cancer patients. Cancer Res 2017;77(13 suppl):CT115.Andtbacka RHI, Curti BD, Kaufman H, Nemunaitis JJ, Daniels GA, Hallmeyer S, et al. Dynamics of tumor response in advanced melanoma patients treated with coxsackievirus A21. J Clin Oncol 2016;34(15 suppl):9553.Silk AW, Kaufman H, Gabrail N, Mehnert J, Bryan J, Norrell J, et al. Phase 1b study of intratumoral coxsackievirus A21 (CVA21) and systemic pembrolizumab in advanced melanoma patients: interim results of the CAPRA clinical trial. Cancer Res 2017;77(13 suppl):CT026.Ethics ApprovalAn independent institutional review board or ethics committee approved the protocol at each study site, and the trial was conducted in compliance with Good Clinical Practice guidelines and the Declaration of Helsinki. All patients provided informed consent.

Prior Exposure to Coxsackievirus A21 Does Not Mitigate Oncolytic Therapeutic Efficacy

Oncolytic viruses (OVs) are being developed as a type of immunotherapy and have demonstrated durable tumor responses and clinical efficacy. One such OV, Coxsackievirus A21 (CVA21), exhibited therapeutic efficacy in early phase clinical trials, demonstrating the ability to infect and kill cancer cells and stimulate anti-tumor immune responses. However, one of the major concerns in using this common cold virus as a therapeutic is the potential for innate and adaptive immune responses to mitigate the benefits of viral infection, particularly in individuals that have been exposed to coxsackievirus prior to treatment. In this study, we assess melanoma responses to CVA21 in the absence or presence of prior exposure to the virus. Melanomas were transplanted into naïve or CVA21-immunized C57BL6 mice and the mice were treated with intratumoral (IT) CVA21. We find that prior exposure to CVA21 does not dramatically affect tumor responses, nor does it alter overall survival. Our results suggest that prior exposure to coxsackievirus is not a critical determinant of patient selection for IT CVA21 interventions.

Clinical Responses of Oncolytic Coxsackievirus A21 (V937) in Patients With Unresectable Melanoma

PURPOSE We evaluated the activity of intratumoral Coxsackievirus A21 (V937) in 57 patients with unresectable stage IIIC or IV melanoma. PATIENTS AND METHODS In this multicenter, open-label, phase II study, patients received up to a total V937 dose of 3 × 108 TCID50 (50% tissue culture infectious dose) in a maximum 4.0-mL volume by intratumoral injection. Ten sets of V937 injections were administered between days 1 and 127 ( NCT01227551 ). Patients who had stable disease or were responding could continue treatment in an extension study ( NCT01636882 ). Response and progression status were based on contrast-enhanced computed tomography, magnetic resonance imaging, or caliper measurement and were categorized using immune-related Response Evaluation Criteria in Solid Tumors (irRECIST). Other evaluations included monitoring of adverse events and serum levels of V937 and anti-V937 antibody titers. The primary efficacy end point was 6-month progression-free survival (PFS) rate per irRECIST. RESULTS The primary efficacy end point, 6-month PFS rate per irRECIST, was 38.6% (95% CI, 26.0 to 52.4). Durable response rate (partial or complete response for ≥ 6 months) was 21.1% per irRECIST. Best overall response rate (complete plus partial response) was 38.6% (unconfirmed) and 28.1% (confirmed) per irRECIST. Regression of melanoma was observed in noninjected lesions. Based on Kaplan-Meier estimation, 12-month PFS was 32.9% (95% CI, 19.5 to 46.9) per irRECIST and 12-month overall survival was 75.4% (95% CI, 62.1 to 84.7). No treatment-related grade ≥ 3 adverse events occurred. Viral RNA was detected in serum within 30 minutes of administration. Neutralizing antibody titers increased to > 1:16 in all patients after day 22, without effect on clinical or immunologic response. CONCLUSION V937 was well tolerated and warrants further investigation for treatment of patients with unresectable melanoma. Studies of combination approaches with V937 and immune checkpoint inhibitors are ongoing.

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

Oncolytic viruses (OVs) are an emerging therapeutic approach for the treatment of cancer. Clinical benefit has been demonstrated for intratumoral administration, but 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. For two Synthetic RNA virus drug candidates, Seneca Valley virus (SVV) and Coxsackievirus A21 (CVA21), we demonstrate vRNA delivery, viral replication, 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 promoted immune cell infiltration and enhanced anti-tumor activity in combination with anti-PD-1 checkpoint inhibitor. Altogether, the Synthetic RNA virus platform provides an innovative approach that enables repeat intravenous administration of viral immunotherapy.

Genetic diversity of Coxsackievirus A21 associated with sporadic cases of acute respiratory infections in Malaysia

Background Coxsackievirus A21 (CVA21), a member of Enterovirus C from the Picornaviridae family, has been associated with respiratory illnesses in humans. Methods A molecular epidemiological investigation of CVA21 was conducted among patients presenting with acute upper respiratory illnesses in the ambulatory settings between 2012 and 2014 in Kuala Lumpur, Malaysia. Results Epidemiological surveillance of acute respiratory infections (n = 3935) showed low-level detection of CVA21 (0.08%, 1.4 cases/year) in Kuala Lumpur, with no clear seasonal distribution. Phylogenetic analysis of the new complete genomes showed close relationship with CVA21 strains from China and the United States. Spatio-temporal mapping of the VP1 gene determined 2 major clusters circulating worldwide, with inter-country lineage migration and strain replacement occurring over time. Conclusions The study highlights the emerging role of CVA21 in causing sporadic acute respiratory outbreaks.