Oncolytics Biotech Inc. (Nasdaq: ONCY) announced it has received written feedback from the U.S. Food and Drug Administration regarding the design of a potential pivotal expansion of its REO 033 clinical study, which is evaluating pelareorep in second-line RAS-mutant, microsatellite stable metastatic colorectal cancer.

The company had submitted a Type D meeting request to the FDA seeking feedback on whether the ongoing randomized Part A of REO 033 could support expansion into a pivotal Part B, and whether that expansion could support a potential accelerated approval pathway based on objective response rate and duration of response, with progression-free survival as the basis for full approval.

The FDA's written responses indicated alignment with the proposed pivotal study design, according to Oncolytics. The FDA also recommended that the company hold an End-of-Phase meeting to finalize key elements of the registration program. Based on this feedback, Oncolytics said it elected to forgo its scheduled Type D meeting and intends to pursue an End-of-Phase meeting as the program advances.

"The feedback provides alignment around the potential use of response rate to support an accelerated approval pathway and progression-free survival to support full approval," said Jared Kelly, Chief Executive Officer of Oncolytics.

REO 033 is a randomized controlled trial evaluating pelareorep combined with folinic acid, fluorouracil, irinotecan, and bevacizumab versus the latter three agents alone. The ongoing Part A enrolls 60 patients and is designed to evaluate clinical activity and inform a potential transition to a pivotal Part B.

Oncolytics said it plans to begin Part B start-up activities as soon as positive interim Part A data become available, with the goal of minimizing the time between supportive data generation and Part B initiation.

Pelareorep combination therapy has received Fast Track designation from the FDA in this patient population. The drug has been administered to more than 1,200 patients across various clinical studies.