Pelareorep Receives FDA Fast Track Status for KRAS-Mutant Colorectal Cancer

The U.S. Food and Drug Administration (FDA) has granted fast track designation to pelareorep, an investigational immunotherapy developed by Oncolytics Biotech, for use in combination with Avastin (bevacizumab) and chemotherapy in patients with KRAS-mutant, microsatellite-stable (MSS) metastatic colorectal cancer in the second-line setting. The designation is based on clinical data suggesting improved outcomes compared with standard-of-care therapy in a population with limited treatment options.

According to the company, pelareorep-based therapy demonstrated higher response rates and longer survival outcomes than what has historically been observed with standard treatments alone. The fast track designation is intended to support the development of therapies that address serious conditions and unmet medical needs and may allow for more frequent interaction with the FDA during the clinical development process.

“This designation is an important validation of our focus on pelareorep’s potential as a platform immunotherapy for gastrointestinal cancers like colorectal cancer,” said Jared Kelly, CEO of Oncolytics. “Adding pelareorep to the standard-of-care in this underserved segment of colorectal cancer patients results in a doubling or tripling of critical clinical endpoints, including overall survival, progression-free survival, and objective response rate in a market that is estimated to be worth several billion dollars. Pelareorep offers the potential to help a meaningful number of patients, and I look forward to continuing to collaborate with the FDA to address this treatment gap as expeditiously as possible.”

Clinical data supporting fast track designation

The FDA’s decision was supported by previously reported clinical data showing a 33% objective response rate among patients treated with pelareorep in combination with Avastin and the chemotherapy regimen leucovorin, fluorouracil, and irinotecan (FOLFIRI). In comparison, historical data suggest an objective response rate of approximately 10% with standard-of-care therapy in this patient population.

Additional outcomes included a median progression-free survival of 16.6 months for patients receiving the pelareorep-based combination, compared with 5.7 months reported with standard therapy. Median overall survival reached 27 months in the pelareorep group, compared with approximately 11.2 months with standard-of-care treatment alone.

These findings contributed to the FDA’s determination that pelareorep may offer an advantage over available therapies in this setting.

Background on KRAS-Mutant MSS Metastatic Colorectal Cancer

Colorectal cancer is among the most commonly diagnosed cancers worldwide, with an estimated 2 million new cases diagnosed each year. Many cases of metastatic colorectal cancer are microsatellite-stable, a characteristic associated with limited responsiveness to currently approved immunotherapies.

KRAS mutations are also common in colorectal cancer and are associated with resistance to certain targeted therapies. Patients whose tumors are both KRAS-mutant and MSS often have few effective treatment options after disease progression on first-line therapy. As a result, this subgroup represents a significant area of unmet medical need in gastrointestinal oncology.

Planned study design and additional findings

The news release announced plans to initiate a controlled clinical study evaluating pelareorep in the second-line treatment of KRAS-mutant MSS metastatic colorectal cancer. The study will compare standard-of-care therapy alone with standard-of-care therapy plus pelareorep.

The first clinical site is expected to open in March, with up to 10 additional sites anticipated to activate shortly thereafter. Interim data from the study are expected by the end of 2026. Further details regarding study design, endpoints, and enrollment criteria are expected to be released by the company at a later date.

The planned study will enroll patients with metastatic colorectal cancer whose disease has progressed following first-line therapy and whose tumors are confirmed to be KRAS-mutant and microsatellite-stable. Molecular testing plays an important role in identifying patients who may be eligible for studies such as this.

Pelareorep has now received fast track designation in two gastrointestinal cancers, reflecting the company’s focus on expanding its development program in this disease area. The designation allows for increased communication with the FDA and may enable eligibility for accelerated approval or priority review if future data continue to demonstrate benefit.

Pelareorep remains investigational, and additional clinical trials are needed to confirm its safety and efficacy before it can be considered for regulatory approval.

References

1. “Oncolytics Biotech® Receives FDA Fast Track Designation for Pelareorep in 2L KRAS-Mutant MSS Metastatic Colorectal Cancer,” by Oncolytics Biotech. News release; Feb. 4, 2026.

Editor's note: This article is for informational purposes only and is not a substitute for professional medical advice, as your own experience will be unique. Use this article to guide discussions with your oncologist. Content was generated with AI and reviewed by a human editor.

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