Oncolytics Biotech Inc. (Nasdaq: ONCY) announced on October 20, 2026, that it will present a trial-in-progress abstract and e-poster at the European Society for Medical Oncology (ESMO) Congress 2026. The presentation, titled "Phase 2 randomized, controlled study of pelareorep combined with 5-fluorouracil/leucovorin/ irinotecan (FOLFIRI) + bevacizumab (bev) for the second-line treatment of RAS-mutated, microsatellite-stable (MSS) metastatic colorectal cancer," will be displayed as e-Poster Number 994eTiP.
The REO 033 study is a randomized, controlled, open-label trial evaluating the investigational immunotherapy pelareorep. The study is designed to validate efficacy signals observed in a previous study, REO 022, and generate data to support future regulatory interactions. The trial is enrolling patients with RAS-mutated, MSS metastatic colorectal cancer who have progressed on first-line oxaliplatin-based therapy.
Patients are randomized 1:1 to one of two arms:
- Arm 1: Pelareorep combined with FOLFIRI and bevacizumab.
- Arm 2: FOLFIRI and bevacizumab alone (standard of care).
The study will enroll 30 patients per arm. The primary endpoint is objective response rate (ORR). Secondary endpoints include overall survival (OS), progression-free survival (PFS), disease control rate, duration of response (DOR), and safety and tolerability. Additionally, blood and tumor samples are being collected for biomarker evaluations.
The company noted that recent interactions with the U.S. Food and Drug Administration (FDA) have provided the opportunity to initiate a pivotal expansion of the REO 033 study (Part B). This expansion could support an accelerated approval submission based on ORR and a full approval based on PFS.
According to data from the REO 022 study, which evaluated patients with similar treatment histories, the ORR, median PFS, median OS, and median DOR were more than doubled in patients treated with pelareorep + FOLFIRI/bevacizumab compared to historical outcomes for patients treated with FOLFIRI and bevacizumab alone. In REO 022, patients treated with the combination saw a median PFS of 17 months, compared to 6 months for the historical standard of care.
