Russell, Luke

Abstract Purpose: VV1 is designed to induce selective oncolysis of tumor cells and amplify cellular antitumor immune responses. This open-label, phase I, multicenter clinical trial assessed the safety and tolerability of VV1 monotherapy administered intratumorally or intravenously or administered intravenously in combination with avelumab. Patients and Methods: Patients with advanced solid tumors received intratumoral (n = 27) or intravenous VV1 monotherapy (n = 33) or intravenous VV1 plus avelumab (n = 16). Infusion durations (15–180 minutes) and viral dose (1.7 × 1010 or 1 × 1011 TCID50) were also evaluated. Study objectives included VV1 safety and tolerability, pharmacokinetics, pharmacodynamics, preliminary efficacy, and immune responses. Results: Intratumoral and intravenous VV1 were well tolerated, and injection reactions were infrequent. The most common adverse events of any grade related to VV1 were cytokine release syndrome (58%), fatigue (33%), and decreased lymphocyte count (32%). Virus infection of tumors was confirmed by NIS imaging and increases in serum levels of virally encoded interferon-β (IFNβ). Histologic tumor analysis at 28 days after intratumoral VV1 administration indicated increases in tumor-infiltrating immune cells. Two durable partial responses were recorded: a patient with pheochromocytoma after one intravenous dose of VV1 and a patient with thymic cancer in the combination arm. Stable disease was observed in 17 of 49 patients (34.7%) who received intravenous VV1. Conclusions: This first-in-human study demonstrates that intratumoral or intravenous VV1 administration had an acceptable safety profile as monotherapy and intravenously in combination with avelumab. There is preliminary antitumor activity. Intratumoral VV1 plus cemiplimab is now showing promise in the neoadjuvant setting. Significance: VV1 is a tumor-selective oncolytic vesicular stomatitis virus engineered to express IFNβ and the thyroidal NIS reporter gene. In this phase I study, we have demonstrated that a single administration of VV1, as a monotherapy or with an immune checkpoint inhibitor is safe, infects tumor lesions resulting in intratumoral infiltration of immune cells, and exhibits early signs of antitumor activity in patients with advanced unresectable and metastatic solid tumors.

e18026 Background: Immune checkpoint inhibitor (ICI) therapy is part of standard of care first-line therapy for recurrent or metastatic (R/M) HNSCC. However, less than 20% of patients (CPS ≥1) have an objective response to ICI monotherapy, and most tumors progress within ~3 months. We sought to improve the proportion of patients who benefit from a chemotherapy-free regimen by combining intratumoral (IT) VV1 oncolytic virus (VSV-IFNβ-NIS) injections with the anti-PD-1 antibody, cemiplimab. We report a pre-planned analysis of Simon's stage 1 results. Methods: We activated a phase 2 study testing the efficacy of first line IT VV1 plus cemiplimab in 1 st line patients with R/M HNSCC. A Simon's two-stage design was employed whereby 10 patients would be accrued in stage 1, and if 3 or more responses were observed, 12 additional patients would be accrued for stage 2. The primary endpoint was objective response rate (ORR) per investigator (RECIST 1.1). Eligible patients had untreated R/M HNSCC from primary oropharynx, oral cavity, hypopharynx, or larynx sites with CPS ≥1. Patients had to have at least one measurable lesion amenable to IT injection. Treatment comprised of IT injections to 1-5 lesions of oncolytic VV-1 virus and IV cemiplimab 350 mg on day 1, repeated every 21 days. Each lesion could be injected 3 times; a 4th injection was allowed if a partial response (PR) was achieved after 3 injections. Cemiplimab could be continued for up to 2 years until progression or unacceptable toxicity. Results: Patient and tumor characteristics, as well as efficacy and toxicity are summarized in the table below. Ten patients were treated at the time of Stage 1 analysis, with 3 showing a confirmed PR for ORR of 30%. Responder CPS scores were 45, 12 and 20%. Two of the responders subsequently showed progression after 6.2 and 9.9 months, the third has maintained PR at 7.7 months to date. Eight of 10 patients showed decrease in the sum of target lesion size (mean decrease of 16%; range -57 to 77%). One grade 2 event of ICI nephritis resolved with corticosteroid treatment. Conclusions: Three patients showed confirmed PR by RECIST 1.1 in Simon's stage 1, meeting criteria to proceed to Simon's stage 2. A total of 22 patients in the HNSCC will be enrolled. VV1 plus cemiplimab shows promise in first line R/M HNSCC based on these initial results. Clinical trial information: NCT04291105 . Patient demographics. N (treated) 10 Sex 20% female Median age (y) 60 (54 – 76) Oropharynx 7 HPV+ 7 Oral cavity 3 PD-L1 CPS median (range) 7.5 (1-45%) Locoregional injection 3 Distant injection 6 Local and distant injection 1 Best response (RECIST 1.1) PR 3 SD 5 PD 2 Adverse Events #pts any VV1/cemiplimab-related G3 AE 4 Lymphopenia 3 Elevated ALK 1