On May 4, 2026 Oncolytics Biotech Inc. (Nasdaq: ONCY) ("Oncolytics" or the "Company"), a clinical-stage company developing pelareorep, an investigational, systemically delivered immunotherapy that has been shown to activate innate immune-sensing pathways, reported new durability data in metastatic colorectal cancer ("mCRC"), demonstrating meaningful and sustained clinical benefit in patients with RAS-mutant, microsatellite-stable ("MSS") disease.
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Pelareorep-based combination therapy demonstrated a 19.5-month median duration of response in second-line ("2L") KRAS-mutant MSS mCRC patients in the REO 022 study, compared to historical benchmarks of approximately 4–6 months in this setting.1 Additional data from this study include an objective response rate of 33% for patients receiving pelareorep, bevacizumab, and FOLFIRI, tripling the 6-11% for the standard of care.2, 3
"We believe these data demonstrate a compelling durability signal for pelareorep in colorectal cancer," said Jared Kelly, Chief Executive Officer of Oncolytics. "A 19.5-month median duration of response in second-line patients—representing a three- to four-fold improvement over historical expectations—highlights pelareorep’s potential to deliver sustained benefit in a population with few effective options. We believe these results support a path toward accelerated approval in second-line RAS-mutant MSS metastatic colorectal cancer, and we are actively engaging with the FDA to align on a regulatory strategy leveraging our ongoing randomized study."
Oncolytics is currently enrolling patients in its randomized Phase 2 study evaluating pelareorep in combination with FOLFIRI and bevacizumab in second-line RAS-mutant MSS mCRC (link to study on ClinicalTrials.gov). The Company is actively engaging with the U.S. Food and Drug Administration ("FDA") to discuss a potential accelerated approval pathway based on response durability and time-to-event endpoints from this study.
Colorectal cancer remains one of the largest oncology markets globally, with significant unmet need in later-line settings. RAS-mutant MSS mCRC represents a particularly difficult-to-treat population, where patients typically experience rapid disease progression and limited durability of response on standard therapies. The magnitude and consistency of durability and patient response observed with pelareorep-based combinations suggest the potential to meaningfully extend clinical benefit in this setting.
(Press release, Oncolytics Biotech, MAY 4, 2026, View Source [SID1234665050])