22 January 2025 – Oncolytics Biotech® Inc. (NASDAQ: ONCY; TSX: ONC) has announced new clinical data for its investigational immuno-oncology therapy pelareorep, presented at the 2025 ASCO Gastrointestinal Cancers Symposium in San Francisco. The findings focus on two particularly challenging tumor types: anal squamous cell carcinoma (SCCA) and pancreatic ductal adenocarcinoma (PDAC), where therapeutic progress has historically been limited.

Anal Cancer Findings from the GOBLET Study

In the anal cancer cohort of the GOBLET platform trial, pelareorep was combined with the PD-L1 inhibitor atezolizumab in patients whose disease had progressed following prior therapies. The study followed a Simon two-stage design, beginning with 12 evaluable patients. Results showed an objective response rate (ORR) of 33%, with four partial responses and one patient achieving a complete response sustained beyond 15 months.

These outcomes are particularly notable when set against historical benchmarks, where immunotherapy with checkpoint inhibitors alone has produced ORRs between 10% and 24% in similar patient groups. Importantly, pelareorep plus atezolizumab demonstrated a tolerable safety profile, with no new safety signals detected.

Further immune analysis revealed that in three of the responding patients, there was evidence of tumor-infiltrating lymphocyte (TIL) clonal expansion by cycle four of treatment. This observation suggests that pelareorep may be enhancing the adaptive immune response against tumor cells. Based on these encouraging results, the study has advanced to Stage 2, which will recruit an additional 18 patients to validate efficacy in a larger cohort.

Progress in Pancreatic Cancer

Pancreatic cancer remains one of the most lethal malignancies, with five-year survival rates lingering below 10% despite advances in chemotherapy. Oncolytics previously reported that pelareorep, when combined with gemcitabine, nab-paclitaxel, and atezolizumab, showed evidence of clinical activity.

The newly disclosed data broaden this picture, demonstrating that pelareorep can also be safely administered with modified FOLFIRINOX—another widely used frontline chemotherapy regimen for metastatic PDAC. Early results indicate that patients tolerated the triplet therapy well, without unmanageable toxicity, opening the door for wider use of pelareorep across different pancreatic cancer treatment backbones.

Strategic Positioning in Immuno-Oncology

Pelareorep is an intravenously delivered oncolytic virus derived from reovirus. Its dual mechanism—direct tumor lysis and stimulation of anti-tumor immune responses—has positioned it as a promising candidate in combination regimens. The current findings underscore its potential to act as an immune primer, enhancing the effectiveness of checkpoint inhibitors and chemotherapy.

The anal cancer data, in particular, provide a clear proof-of-concept: patients not only responded but, in some cases, achieved long-lasting remissions, a critical outcome in a disease setting where second-line treatment options are scarce. The expansion into FOLFIRINOX combinations in pancreatic cancer further signals flexibility and a path toward integration into existing treatment standards.

Looking Ahead

With recruitment now underway for the Stage 2 anal cancer cohort, Oncolytics Biotech is aiming to gather more robust data that could justify advancing pelareorep toward pivotal studies. In pancreatic cancer, the confirmation of safety alongside FOLFIRINOX provides the foundation for larger trials designed to assess survival benefits in a notoriously resistant cancer.

The updates at ASCO-GI 2025 mark a meaningful step forward for pelareorep’s development trajectory. By demonstrating durable responses in anal cancer and expanding its reach into pancreatic regimens, the company has strengthened its clinical case for broader adoption. As the field of immuno-oncology continues to evolve, agents like pelareorep that enhance immune engagement may prove vital in turning the tide against hard-to-treat gastrointestinal malignancies.