BriaCell presents OS data in MBC patients treated with Bria-IMT/CPI regimen

BriaCell (BCTX) Therapeutics is pleased to showcase its survival and clinical benefit data in MBC patients, including those with CNS metastases, treated with the Bria-IMT plus CPI regimen. The data is featured in BriaCell’s “Spotlight” poster presentation session, at the 2024 San Antonio Breast Cancer Symposium held at Henry B. Gonzalez Convention Center, San Antonio, TX. The data presented is from the fully enrolled BriaCell Phase 2 combination study of Bria-IMT plus CPI. An aggregate of 54 MBC patients were enrolled in the study – all treated with the Bria-IMT combination regimen. Data is available on all 54 of these heavily pre-treated metastatic breast cancer patients. Of these 54 patients, 37 were treated with the formulation currently under investigation in BriaCell’s ongoing pivotal Phase 3 study in metastatic breast cancer. Final median overall survival calculation for the patients in the Phase 2 portion of the study is pending, as most of these patients remain alive over 1 year following their start on the study. No Bria-IMT related discontinuations have been reported to date.Title: Overall survival results of Bria-IMT allogenic whole cell-based cancer vaccine: Bria-IMT regimen’s OS and tolerability in MBC patients: Median overall survival to date of 13.4 months for Phase 2 patients treated with the Phase 3 formulation double that of comparable patients in the literature. Final Phase 2 OS calculation is pending as many patients remain alive well over 1 year after starting the study. Median overall survival for patients who received the Phase 3 formulation in the Phase 2 portion of the study who also developed an immune response to the vaccine as measured by delayed-type hypersensitivity not yet reached with greater than1 year follow-up. 13.7 months median OS in MBC patients with central nervous system /intracranial tumors treated with the Bria-IMT regimen with or without a CPI. Objective response rates and clinical benefit rates were observed across all MBC patient subsets, but positive clinical outcomes were more prominent in HER2+ and HR+/HER2- patient subsets. Bria-IMT regimen was well-tolerated and produced clinical benefit in heavily pretreated MBC patients. Patients who developed a DTH response had lower neutrophil to lymphocyte ratio, suggesting improved clinical benefit in these patients. Delayed-type hypersensitivity response, and circulating tumor cells levels were significantly different between patients who responded vs those who did not respond to the Bria-IMT combination regimen. In conclusion, clinical findings to date support the potential safety and efficacy of Bria-IMT, along with its potential use in CNS metastases, as well as the possible use of biomarkers to predict clinical outcomes in BriaCell’s ongoing pivotal Phase 3 study in MBC. Title: Identification of antigenic determinants in SV-BR-1 derived cellular breast cancer vaccines: Summary: BriaCell successfully identified immunogenic peptides in patients treated with Bria-IMT, a cell-based cancer vaccine, and showed Bria-IMT’s ability to produce a targeted immune response against tumor antigens. Key immunogenic peptides detected included those with post-translational modifications, such as citrullination and cysteinylation, an important type of neoantigen that may be shared across many patients with cancer. Highlighted the advantage of cell-based cancer vaccines over RNA and peptide-based vaccines including their ability to present a broad and diverse repertoire of antigens. Cell-based cancer vaccines also display unknown, patient-specific neoantigens that are hard to reproduce with RNA or peptide vaccines. Diverse antigen presentation produces a robust, polyclonal immune response, engaging both CD8+ and CD4+ T cells against multiple tumor target. In conclusion, scientific data presented suggests that the unique mechanism of cell-based cancer vaccines may reduce cancer cells’ immune escape and may potentially lead to strong and long-lasting clinical outcomes in cancer patients. Title: PD-L1 upregulation in circulating tumor associated cells predicts for clinical outcomes in a phase I/II clinical trial using SV-BR-1-GM vaccine with the checkpoint inhibitor retifanlimab in metastatic breast cancer patients, an interim analysis: Summary: Interim analysis after at least one year of Bria-IMT plus CPI regimen shows the following: Significantly lowered levels of circulating tumor cells and cancer associated macrophage-like cells in 40% of heavily pre-treated MBC patients. Lower CTCs/CAMLs levels were significantly correlated with better survival outcomes. Bria-IMT appeared to increase PD-L1 levels in 15 patients which correlated with better clinical responses to combination treatment with the anti-PD-1 check point inhibitor retifanlimab. In conclusion, clinical data support the combination regimen in our ongoing pivotal Phase 3 study and suggests CTCs and CAMLs and PD-L1 levels may be relevant indicators of clinical outcome in MBC patients treated with Bria-IMT plus CPI. Abstract Title: ASTRO-VAC CNS: Bria-IMT in the management of tumor agnostic metastatic CNS lesions: Results: The poster provides the details of a planned Phase 2 study design expanding the use of Bria-IMT + CPI to tumor agnostic cancer patients with central nervous system metastasis.