CTIM-20. SYSTEMIC IMMUNE CORRELATES ASSOCIATED WITH LONG-TERM SURVIVAL AFTER THERAPEUTIC ADENOVIRUS (DNX2401) PLUS INTERFERON GAMMA FOR RECURRENT GLIOBLASTOMA EFFECT TRIAL (TARGET): A RANDOMIZED PHASE 1 TRIAL

Abstract Anti-tumor immune response following oncolytic virus treatment of glioblastoma may be enhanced by immune activating therapies. Here, in this Phase Ib, multicenter, randomized, open-label study we evaluated the combination of intra-tumoral delivery of oncolytic virus DNX-2401 with subcutaneous interferon gamma (IFN-γ) a T-helper 1 response activator in 37 patients with recurrent glioblastoma. In part 1, 27 patients were randomized 2:1 into DNX-2401 with IFN-γ and DNX-2401 alone with intra-tumoral DNX-2401 administered via a standard biopsy needle. In part 2, 10 patients received intra-tumoral DNX-2401 via an FDA-approved Alcyone MEMS Cannula designed to prevent backflow at high infusion flowrates. DNX-2401 was well tolerated but the addition of IFN- γ was not well tolerated. The primary efficacy endpoint, objective clinical response, was not met. The secondary endpoint of 12-month overall survival for DNX-2401 with IFN-γ, DNX-2401 alone and DNX-2401 via Cannula were 33%, 22%, 0% respectively. The 18-month OS for DNX-2401 with IFN-γ, DNX-2401 alone and DNX-2401 via Cannula were 25%, 9%, 0% respectively. The DNX-2401 with IFN- γ cohort had the most long-term survivors (44.2, 23.7, 20.6 and 20.1 months). Systemic antibody and immune cell profiling following DNX-2401 treatment showed that long term survivors had significantly higher anti-adenovirus specific antibody reactivity and a higher activated CD8+ effector memory T-cell sub-population at 2 months post-treatment relative to baseline. This systemic immune response did not occur in short term survivors following DNX-2401 treatment. Overall, these data suggest that an early and robust systemic adaptive immune response could be used as a biomarker for long term survival following DNX-2401 treatment of recurrent glioblastoma independent of other salvage treatments administered following disease progression during the trial. (Clinical Trial.gov registration: NCT02197169).