Combination of Pelareorep and Radiotherapy Shows Promise

By News Release


New preclinical data demonstrates the synergistic immunotherapeutic effects of pelareorep combined with radiotherapy in a murine cancer model. The data from Oncolytics Biotech were featured in a poster presentation at The International Conference on Immunotherapy Radiotherapy Combinations in Paris from September 14-17, 2021.

Preclinical studies presented in the poster evaluated various treatment combinations of pelareorep, ionizing radiation (radiotherapy), and anti-PD-1 therapy in mice with two bilateral tumors, each located subcutaneously (under the skin) on a different side of the body. Radiotherapy and/or pelareorep treatment was delivered locally to one tumor (denoted the primary tumor), while the second tumor (denoted the abscopal tumor) was not directly exposed to either therapy. Anti-PD-1 therapy was delivered systemically.

Results showed that in primary tumors, pelareorep monotherapy led to a numerical increase in the number of infiltrating anti-cancer CD8+ T cells, which reached statistical significance when combined with radiotherapy (a 15-fold increase compared to control). In abscopal tumors, both pelareorep monotherapy and pelareorep-radiation combination therapy led to a statistically significant increase in infiltrating anti-cancer CD8+ T cells. This effect was not seen with single-agent radiotherapy in either the primary or the abscopal tumors.

Local delivery of radiotherapy alone and the pelareorep-radiotherapy combination into primary tumors significantly improved survival compared to untreated controls. Compared to single-agent radiotherapy, the pelareorep-radiotherapy combination led to a numerical increase in survival, which reached statistical significance when anti-PD-1 therapy was added to the treatment regimen.

“The observed increases in survival and in the number of anti-cancer immune cells within both primary and abscopal tumors following treatment is indicative of the synergistic immunotherapeutic effects of the pelareorep-radiotherapy combination,” said Thomas Heineman, MD, PhD, Global Head of Clinical Development and Operations at Oncolytics. “This is a compelling finding that has the potential to be broadly applicable across multiple cancer indications and warrants further study. Together with prior clinical and preclinical data, these results also highlight pelareorep's potential as an enabling technology to enhance the efficacy of a wide range of therapies.”