BriaCell Therapeutics Corp. announced positive clinical efficacy data updates of its ongoing randomized Phase 2 study evaluating lead clinical candidate Bria-IMT in patients with advanced metastatic breast cancer. Two poster sessions, one abstract, and one oral presentation session (by Principal Investigator and Professor of Oncology, Mayo Clinic, Saranya Chumsri, MD), will be presented at the 2024 American Society of Clinical Oncology (ASCO) Annual Meeting taking place June 3, 2024 at McCormick Place, Chicago, IL.

Oral Presentation Summary: Abstract Number for Publication: 1022; Title: Outcomes of advanced/metastatic breast cancer (aMBC) treated with Bria-IMT?, an allogeneic whole cell immunotherapy. Session Type and Title: Rapid Oral Abstract ? Breast Cancer?Metastatic; Session Date and Time: 6/3/2024; 11:30 AM-1:00 PM CDT.

This presentation details the results of BriaCell?s randomized Phase 2 study of Bria-IMT? in combination with retifanlimab, an immune checkpoint inhibitor (CPI). The goal of randomization was to compare whether administration of the CPI early, in the first cycle of therapy, or later, late in the second cycle of therapy, offered any advantage.

Two different formulations of Bria-IMT? were also evaluated; one treated with interferon gamma and one untreated. A total of 54 patients were included in the Phase 1/2 study.

Nearly half of these had been treated previously with an antibody drug conjugate and had progressed in their disease following this treatment. Another 20% had failed a prior immune checkpoint inhibitor. Nearly 2/3 of the patients had failed therapy with a CDK 4/6 inhibitor.

On average they had failed six prior therapy attempts. In the Phase 2 portion of the study, there were 32 patients with 16 treated with CPI early and 16 treated with CPI late. There was no statistically significant difference in progression-free survival (PFS) two groups.

However, a slight advantage in the CPI early group has led this to be the selected regimen for the Phase 3 study. In the entire Phase 1/2 experience, with 54 patients, the formulation not incubated with interferon gamma showed a statistically significant improvement in PFS. Therefore, this formulation was selected for the Phase 3 study.

The progression free survival rate and the clinical benefit rate as well as the objective response rate were markedly higher than those of similar patients treated with the treatment of their physician?s choice in other studies. Poster Presentation Summary: The first poster described BriaCell?s ongoing pivotal Phase 3 registrational study in advanced metastatic breast cancer. BriaCell is excited to collaborate on this important program with authors and BriaCell medical advisory board members Sara A. Hurvitz, MD, Professor of Medicine, Fred Hutchinson Cancer Center, Adam M. Brufsky, MD, PhD, Professor of Medicine, University of Pittsburgh School of Medicine, and Massimo Cristofanilli, MD, Professor of Medicine, Weill Cornell Medical College, Cornell University.

The second poster described clinical data of Bria-IMT? in metastatic breast cancer patients who failed antibody drug conjugates (ADCs) and is spearheaded by Chaitali Nangia, MD, Partner, Hoag Medical Group, and Carmen Calfa, MD, Professor of Medicine, University of Miami. Abstract Number for Publication: TPS1137; Title: Study of the Bria-IMT?

regimen and CPI vs physicians' choice in advanced metastatic breast cancer (BRIA-ABC). Based on Phase 2 clinical data showing numerous survival and clinical benefit outcomes in advanced breast cancer patients treated with the Bria-IMT? regimen, the pivotal Phase 3 study has been designed as a multicenter randomized, open label comparison of the Bria-IMT?

regimen plus CPI in one arm versus Treatment of Physicians' Choice (TPC) in metastatic breast cancer patients with no approved alternative therapies available. Patients? eligibility includes treatment with 2 or more prior regimens.

There will be another arm of the Bria-IMT? regimen alone (monotherapy). For additional information on the pivotal Phase 3 study, please visit ClinicalTrials.gov as NCT06072612.

Abstract Number for Publication: 1087; Title: SV-BR-1-GM after progression on ADC in patients with metastatic breast cancer. Remarkable progression-free survival and clinical benefit of Bria-IMT? in ADC resistant advanced metastatic breast cancer: Phase 2 clinical data of the Bria-IMT?

regimen in 23 advanced metastatic breast cancer patients who failed multiple prior treatments including ADCs and CPIs (median of 6 prior treatments) are presented. Clinical efficacy: In evaluable patients, the ORR was 12% and CBR was 53% which is remarkable versus similar data suggesting clinical benefit. Median PFS of 4.1 months with the Phase 3 formulation was twice that seen of patients in similar studies - 1.7 and 2.2 months - who received TPC.

The PFS results suggest superior clinical efficacy given the larger number of prior treatments (median of 6) in Bria-IMT? patients vs those of the other studies (median of 4). Subset specific clinical benefits: Study data to date suggests clinical benefit for multiple breast cancer subtypes including HR+/HER2- (the most common breast cancer subtype, testing positive for estrogen and/or progesterone receptors and negative for human epidermal growth factor receptor 2 or HER2) with a CBR following treatment, of 63% (5 of 8 patients); HER2+ subtype (a positive test for HER2) with a 100% CBR (2 of 2 patients) and HR-/HER2 low subtype (a negative test for estrogen and/or progesterone receptor and a negative test for HER2) showing a CBR of 66% (2 of 3 patients).