Oncolytics Biotech Inc. (Nasdaq: ONCY) announced preclinical results evaluating its investigational therapy pelareorep in combination with a pan-RAS inhibitor in a RAS-driven colorectal cancer model, according to a company statement.

During an initial treatment period with pelareorep administered every other day, pelareorep alone, the pan-RAS inhibitor alone, and the combination each reduced tumor growth compared to a control group. The greatest tumor reductions were observed in the RAS inhibitor and combination groups. The company said pelareorep activity was maintained in the presence of RAS inhibition, with no evidence of antagonism between the two therapies.

When dosing shifted to less frequent weekly pelareorep administration, the incremental activity associated with pelareorep became less evident. Oncolytics said the findings support further evaluation of optimized pelareorep dosing schedules alongside RAS inhibitors.

Thomas Heineman, MD, PhD, Chief Medical Officer of Oncolytics, said the results showed "pelareorep activity during the initial intensive dosing period as well as biologic compatibility between pelareorep and RAS inhibition." He added that "acquired resistance remains a major limitation of RAS-targeted therapies" and that the findings provide rationale to investigate whether sustained pelareorep activity can deepen and prolong responses to RAS inhibition.

The company said the results are consistent with previously published independent research indicating that RAS inhibitors do not interfere with the mechanism through which pelareorep selectively infects tumor cells.

Oncolytics plans to expand preclinical evaluation of pelareorep with RAS inhibitors across additional dosing schedules and RAS-driven tumor models. Pelareorep has received Fast Track designation from the U.S. Food and Drug Administration for colorectal, anal, and pancreatic cancer.