BriaCell Therapeutics Corp. (Nasdaq: BCTX) announced positive survival data for its Bria-IMT™ plus immune checkpoint inhibitor combination therapy in metastatic breast cancer. The Phase 2 study revealed a median overall survival of 13.4 months, surpassing historical controls. These findings will be presented at the 2024 San Antonio Breast Cancer Symposium® (SABCS®).
The Phase 2 study included 54 patients and showed a 9.5% objective response rate and a 55% clinical benefit rate across all breast cancer subtypes. The therapy demonstrated efficacy in patients with low circulating tumor cell counts and positive delayed type hypersensitivity responses.
Clinical Efficacy and Patient Subtypes
Saranya Chumsri, MD, Principal Investigator and Professor of Oncology at Mayo Clinic, stated, "In the Phase 2 study, the Bria-IMT™ combination regimen significantly increased overall survival versus comparable published benchmarks. Objective response rate and clinical benefit rate data support the potential benefit of Bria-IMT™ plus CPI in patients with this difficult-to-treat cancer."
The survival benefit was observed across various breast cancer subtypes, including HER2+, HR+/HER2-, and triple-negative breast cancer (TNBC). This broad efficacy is particularly valuable as most current therapies are subtype-specific.
Biomarkers and Patient Selection
The study identified potential biomarkers, such as circulating tumor cell (CTC) counts and delayed type hypersensitivity (DTH) responses, to predict treatment outcomes. Patients with post-dose CTC counts < 5 had a significantly better overall survival compared to those with CTC counts > 5 (13.4 vs. 5.5 months, P < 0.01).
Giuseppe Del Priore, MD, MPH, BriaCell’s Chief Medical Officer, noted, "Our clinical findings support the use of the current Phase 3 formulation. We plan to confirm the potential use of key biomarkers to predict patient clinical outcomes in the Bria-IMT™ plus CPI ongoing pivotal Phase 3 study."
Implications for Treatment
The positive survival data in patients who had previously failed checkpoint inhibitor and antibody-drug conjugate therapy suggests that Bria-IMT™ could fill an important treatment gap. The therapy's efficacy against CNS metastases addresses a critical unmet need in breast cancer treatment.
Dr. William V. Williams, BriaCell’s President & CEO, stated, "BriaCell’s clinical data demonstrating impressive overall survival in all patient subsets including very difficult to treat patient populations, such as those who have failed prior checkpoint inhibitor and/or antibody-drug conjugate therapy, reinforces our confidence in the potential use of the combination regimen in MBC patients."
Future Directions
BriaCell is planning a Phase 3 trial to validate these promising results. The collaboration with the Medical College of Wisconsin will investigate the use of Bria-IMT™ + CPI in any cancer patient with central nervous system (CNS) metastases.
