Why Did Oncolytics Biotech Inc. (ONCY) Plunge 25.84% Post-ASCO Data?

On May 27, 2025, Oncolytics Biotech Inc. (ONCY) experienced a significant drop of 25.84% in pre-market trading. This sharp decline in stock price can be attributed to several factors, including the company's recent clinical trial data presentations and market sentiment.

Oncolytics Biotech recently presented new clinical trial data at the American Society of Clinical Oncology (ASCO) Showing Pelareorep's Unique Immune Activation Capabilities. The data highlighted Pelareorep's ability to initiate a pro-inflammatory tumor microenvironment and induce both innate and adaptive immune responses. This presentation was part of a broader effort by Oncolytics to showcase the potential of its immunotherapeutic agent, Pelareorep, which is currently in Phase 3 clinical trials for the treatment of hormone-refractory metastatic prostate cancer.

Despite the promising data presented at ASCO, the market's reaction to Oncolytics Biotech's stock was negative. This could be due to investor concerns about the company's financial health, the competitive landscape in the immunotherapeutic space, or broader market trends affecting biotechnology stocks. Additionally, the company's reliance on a single therapeutic agent, Pelareorep, may have contributed to investor caution, as the success of the stock is heavily dependent on the outcomes of ongoing clinical trials.