Phase 1b study of oncolytic vaccinia virus GL-ONC1 in recurrent ovarian cancer (ROC).

5577Background: Immunotherapy can trigger immune activation including tumor-infiltrating CD8+ T cells, leading to antitumor response and survival benefits. Immunotherapeutic GL-ONC1 (modified vaccinia virus) causes oncolysis, immune activation and durable anti-cancer memory. Methods: Intraperitoneal infusion of GL-ONC1 monotherapy was given at higher repeated doses compared to a previous Ph1 trial in patients (pts) with platinum refractory/resistant disease. Primary endpoint: adverse events; Secondary endpoints: anti-tumor response by RECIST1.1 & survival. Eleven heavily pretreated pts with end-stage ROC were enrolled: 3-4 prior lines (n = 3), ≥ 5 lines (n = 8), ECOG 0 (n = 7) or 1 (n = 4), ascites/pleural effusion (n = 9) & progressive disease (PD) at baseline (n = 10). There were two dose cohorts: 3 × 109 (n = 6) or 1 × 1010 (n = 5) plaque forming units/day on 2 consecutive days. Results: (1) Adverse reactions included Grade 1-2 chills (n = 7), nausea (7), fever (6), abdominal pain/distention (4), & vom...