Updated results from the Phase 1 REO 022 trial show that pelareorep (Reolysin), an oncolytic virus, added to standard FOLFIRI and bevacizumab may significantly improve outcomes in RAS-mutant, microsatellite-stable metastatic colorectal cancer.
The combination performed much better than historical results for second-line treatment. Median duration of response reached 19.5 months compared with about 4 to 6 months normally. The objective response rate was 33% versus 6% to 11% with standard therapy alone. Median progression-free survival was 16.6 months compared with about 5.7 months, and overall survival reached 27 months versus roughly 11 months.
Pelareorep works by selectively infecting cancer cells and activating the immune system against the tumor. The FDA has granted Fast Track designation, and Oncolytics Biotech is working with regulators on a possible accelerated approval pathway. A Phase 2 study is now ongoing to confirm these findings.