Oncolytics Biotech (ONCY) and SOLTI Achieve Primary Endpoint in AWARE-1 Study

Oncolytics Biotech® Inc. (NASDAQ: ONCY) (TSX: ONC), together with SOLTI, recently announced new clinical data from the AWARE-1 window-of-opportunity breast cancer study showing patients receiving pelareorep plus checkpoint blockade therapy met the trial's primary endpoint. These data are featured in an electronic poster at the American Association for Cancer Research (AACR) Annual Meeting 2021 during Week 1, which is taking place virtually from April 10-15, 2021.

In the poster, data from the twenty HR+/HER2- early-stage breast cancer patients included in AWARE-1's first two cohorts are presented. These patients were treated with pelareorep and letrozole without (cohort 1) or with (cohort 2) the PD-L1 inhibitor atezolizumab (Tecentriq®) prior to surgery. Evaluation of cohorts 1 and 2 is the core objective of AWARE-1, as HR+/HER2- is the breast cancer subtype Oncolytics intends to examine in a future registrational study.

Pelareorep treatment in cohort 1 upregulated tumor PD-L1 expression, induced the generation and expansion of T cell clones, promoted tumor infiltration of CD8+ T cells, and increased the CelTIL score, a measure of tumor cellularity and inflammation associated with favorable clinical outcomes. These desired outcomes were further enhanced in cohort 2 patients, demonstrating pelareorep and atezolizumab synergistically combine to generate an anti-cancer immune response in the tumor and peripheral blood. Notably, cohort 2 met the pre-specified success criteria for the study's primary endpoint (50% of patients with ≥ 30% increase in CelTIL score), with six of ten patients achieving at least a 30% increase in CelTIL score following treatment.

"These exciting AWARE-1 data confirm pelareorep promotes a pro-inflammatory tumor microenvironment, allowing it to synergistically interact with checkpoint inhibitors to train the immune system to fight cancer," said Aleix Prat, M.D., Ph.D., Translational Principal Investigator of AWARE-1, SOLTI President and Head of the Medical Oncology Department at Hospital Clinic in Barcelona. "The data show combining pelareorep with anti-PD-L1 therapy led to increases in CelTIL score and an improvement in the ratio between cytotoxic CD8+ T cells to regulatory T cells. These striking immunological changes are associated with greater therapeutic efficacy and improved clinical outcomes. Collectively, the AWARE-1 results highlight pelareorep's potential to address the unmet need for techniques to enhance checkpoint inhibitor efficacy and strongly support the continued clinical evaluation of pelareorep-checkpoint inhibitor combinations."

Key data and conclusions from the AACR poster include:

• Treatment with pelareorep alone or in combination with atezolizumab increased tumor PD-L1 expression and led to the conversion of PD-L1 negative tumors into PD-L1 positive tumors
• Pelareorep profoundly reverses immunosuppressive tumor microenvironments and promotes immune effector cell infiltration into solid tumors, positioning it as an enabling technology for a variety of immunotherapeutic agents
• Tumor-cell specific pelareorep replication was observed in all evaluated patients following intravenous pelareorep administration
• 60% of cohort 2 patients (n=10) saw a CelTIL increase of at least 30% from baseline (pre-pelareorep administration) to surgery (21-days post-administration), exceeding the study's pre-specified success criteria
• 70% of all cohort 1 and 2 patients (n=20) saw an increase in CelTIL from baseline to surgery
• The addition of atezolizumab enhances pelareorep's ability to generate and expand new anti-viral and anti-tumor T cell clones in the tumor and periphery
• Compared to cohort 1, cohort 2 patients had a higher ratio of CD8+ T cells to regulatory T cells, suggesting pelareorep and checkpoint inhibition enhances inflammation within the tumor microenvironment

Thomas Heineman, M.D., Ph.D., Global Head of Clinical Development and Operations at Oncolytics, commented, "Based on these new results, we have successfully achieved two key objectives of the AWARE-1 study. We've demonstrated synergy between pelareorep and checkpoint blockade therapy, and we've shown pelareorep triggers an adaptive T cell immune response specifically targeting tumors."

Matt Coffey, Ph.D., M.B.A., President and Chief Executive Officer of Oncolytics Biotech Inc. added, "Achieving the primary endpoint in AWARE-1 is a key milestone validating our clinical development strategy. Data indicating that pelareorep and atezolizumab synergistically interact de-risks both our lead breast cancer program and our additional clinical trials evaluating pelareorep-checkpoint inhibitor combination therapies. The data also highlight pelareorep's ability to profoundly reverse immunosuppressive tumor microenvironments and promote immune effector cell infiltration into solid tumors, positioning it as an enabling technology for a variety of immunotherapeutic agents. Moving forward, we expect these data to facilitate the advancement of our lead breast cancer program towards a registrational study while simultaneously bolstering our business development efforts across several indications and immunotherapy treatment regimes."

The electronic poster, titled "A window-of-opportunity study with atezolizumab and the oncolytic virus pelareorep in early breast cancer (AWARE-1)" is available for on-demand viewing on the AACR Annual Meeting 2021 e-poster website and on the Posters & Publications page of Oncolytics' website (LINK).

Key Opinion Leader Event

Oncolytics will host a Key Opinion Leader (KOL) event today at 2:00 pm ET with Aleix Prat, M.D., Ph.D., Translational Principal Investigator of AWARE-1, SOLTI President and Head of the Medical Oncology Department at Hospital Clinic in Barcelona and Dr. Richard Vile, a Professor of Immunology at the Mayo Clinic, who led the preclinical CAR T study with pelareorep presented earlier this year (link to press release, link to poster). To access the webcast, please click this link.

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