Oncolytics gets FDA feedback on pivotal path for pelareorep in colorectal cancer
The FDA's written response addresses a possible accelerated approval route for REO 033's Part B expansion in second-line RAS-mutant MSS metastatic colorectal cancer.
Oncolytics Biotech announced on August 18, 2026 that it had received written feedback from the FDA regarding the design of a potential pivotal Part B expansion of REO 033, its ongoing randomized study of pelareorep in second-line RAS-mutant, microsatellite stable metastatic colorectal cancer.1
The company had submitted a Type D meeting request to the FDA about expanding REO 033 into a pivotal study.1 In that request, Oncolytics asked the FDA whether the current Part A design could support a pivotal Part B, and whether such a Part B could support accelerated approval using objective response rate and duration of response, with progression-free survival as the basis for full approval.1
According to the company, the FDA's written responses reflect what Oncolytics views as meaningful alignment on the proposed pivotal study design.1 The FDA also recommended that the company hold an End-of-Phase meeting to finalize agreement on key elements of the registration program.1 Given this feedback, Oncolytics decided to skip its scheduled Type D meeting in favor of pursuing that End-of-Phase meeting as the program moves forward.1
REO 033 is currently testing pelareorep alongside standard-of-care therapy in second-line RAS-mutant, MSS metastatic colorectal cancer patients, and was designed with the option to expand into a pivotal Part B if Part A results and regulatory feedback support it.1 Based on the FDA's feedback, Oncolytics plans to begin Part B start-up activities as soon as positive interim Part A data become available, to shorten the gap between data and initiation.1
The company cites earlier data from REO 022 showing improvements in objective response rate, duration of response, progression-free survival and overall survival with pelareorep combination therapy, which has Fast Track designation from the FDA in this population.1 Part A of REO 033 enrolls 60 patients and is meant to generate data supporting a decision on the pivotal Part B transition.1
Written by readthrough’s AI from the linked primary sources and fact-checked against them automatically before publishing. Not investment advice.