Effect of CVA21, an Oncolytic Virus, in combination with Pembrolizumab on immunogenicity and the tumour microenvironment in advanced NSCLC: a phase I/II trial

Acquired or de novo resistance to immune checkpoint inhibitors occurs in the majority of advanced non-small cell lung cancers (NSCLC). There is an unmet need to improve outcomes for patients with this condition. Oncolytic viruses represent an attractive treatment approach due to their dual activity in inducing tumor cell lysis directly and potentially augmenting anti-tumor immunity. Here, we present the safety, efficacy and translational findings from a phase I/II single-arm trial utilising CVA21, an oncolytic coxsackie virus, in combination with pembrolizumab in patients with advanced pre-treated NSCLC. We performed paired biopsies pre- and post-treatment in 10 patients who received intravenous CVA21 and pembrolizumab, 8 of whom had prior treatment with immune checkpoint inhibitor (ICI) therapy. Whole genome sequencing and spatial proteomics were performed to comprehensively characterise the response to CVA21. Combination CVA21/pembrolizumab (anti PD-1) therapy was well tolerated with no serious treatment-related adverse events. Partial responses were seen in two patients with prior acquired anti-PD-1 resistance and disease stabilisation in 6 patients, giving a clinical benefit rate of 80%. High baseline tumor mutational burden and PD-L1 expression were observed in patients with better response to treatment. Interestingly, an increase in antigen presentation and CD8+ T cell infiltration was observed on treatment compared with baseline in patients with better progression-free survival. This study demonstrates the potential of CVA21 to modulate the immunogenicity of tumor cells and remodelling the tumor microenvironment, providing novel insights for patient selection for trials involving novel immunotherapeutic approaches.