REO 017 was a single-arm, open-label Phase II study of REOLYSIN® in combination with gemcitabine in patients with advanced or metastatic pancreatic cancer. Patients received gemcitabine on days 1 and 8 of each twenty-one day cycle, and REOLYSIN® on days 1, 2, 8 and 9. Approximately 33 patients were enrolled in the study. The primary objective was clinical benefit rate (complete response (CR) plus partial response (PR) plus stable disease (SD)). The secondary objectives were progression-free survival, and the safety and tolerability of the treatment regimen.
Final data from the study was presented by Oncolytics collaborators at the ESMO World Congress on Gastrointestinal Cancer in July 2015. Median progression-free survival for the study was four months, and median overall survival was 10.2 months. One- and two-year survival rates were 45% and 24%, respectively. The data suggested that the drug combination could increase median overall survival, and showed an approximately two-fold increase in one-year survival rates, and a five-fold increase in two-year survival rates, when compared to historical data assessing gemcitabine therapy alone. Of the 29 patients evaluable for clinical response, one patient had a partial response, 23 had stable disease and five had progressive disease as their best response. This translated into a clinical benefit rate of 83%. In addition, a further analysis demonstrated upregulation of the immune checkpoint marker PD-L1 in post-treatment tumours, suggesting the potential to combine oncolytic viral therapy with anti-PD-L1 inhibitors in future trials.