BCTX BriaCell Therapeutics Corporation

BriaCell Therapeutics Corp. (Nasdaq: BCTX, BCTXW, BCTXZ), (TSX: BCT) (“BriaCell” or the “Company”), a clinical-stage biotechnology company developing novel immunotherapies to transform cancer care, today announces the presentation of positive survival and clinical benefit data in three clinical poster presentations and one publish-only abstract at the upcoming 2025 American Society of Clinical Oncology (ASCO) Annual Meeting taking place May 30 – June 3 at McCormick Place, Chicago, IL.

“We are highly encouraged by the survival and clinical benefit data from our Phase 2 Bria-IMT™ study which meets and outperforms outcomes seen with FDA approved therapies - despite our patients being more heavily pre-treated,” stated Dr. William V. Williams, BriaCell’s President & CEO. “These results reinforce our belief in Bria-IMT’s potential to address the urgent, unmet needs of patients with metastatic breast cancer and we look forward to confirming results in our ongoing pivotal Phase 3 study.”

“These data provide additional validation of the mechanism of action and support the clinical efficacy of Bria-IMT,” noted Giuseppe Del Priore, MD, MPH, BriaCell’s Chief Medical Officer. “Importantly, the regimen has been well-tolerated and its favorable safety and efficacy profile positions it as a promising, less toxic therapeutic option for patients battling metastatic breast cancer.”

The details of the poster presentation sessions and publish-only abstract are listed below.

Abstract Title: Update on phase III pivotal trial of Bria-IMT + CPI vs physician’s choice in advanced metastatic breast cancer (BRIA-ABC) Session Date and Time: June 2, 2025 9:00 AM-12:00 PM CDTAbstract Number for Publication: TPS1138 Poster Board Number: 108aSession Type and Title: Poster Session – Breast Cancer—Metastatic

Preliminary selected clinical and biomarker data from BriaCell’s ongoing pivotal Phase 3 study of Bria-IMT plus an immune checkpoint inhibitor (CPI) in metastatic breast cancer (NCT06072612).

Abstract Title: Bria-IMT + checkpoint inhibitor: Phase I/II survival results compared to benchmark trials in metastatic breast cancerSession Date and Time: June 2, 2025 9:00 AM-12:00 PM CDTAbstract Number for Publication: 1096Poster Board Number: 75Session Type and Title: Poster Session – Breast Cancer—Metastatic

Phase 2 study of Bria-IMT in combination immunotherapy with an immune checkpoint inhibitor (CPI) consisted of 54 patients; 11 received pembrolizumab, 44 retifanlimab (1crossover).

Table 1: Median overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and clinical benefit rate (CBR) were evaluated against two pivotal Phase 3 studies of FDA approved drugs, ASCENT (Trodelvy® (SG) or Treatment of Physicians Choice (TPC) in triple-negative breast cancer (TNBC)) and TROPiCS-02 (SG or TPC in Hormone Receptor +/HER2- MBC)
Trial (Cohort)	Age (median, range)	Prior Therapies (median, range)	OS (months)	PFS (months)	ORR(%)	CBR(%)
Bria-IMT (Overall Cohort)	61 (38-81)	6 (2-13)	9.9 (1.8-30.3)	3.6	10%	55%
Bria-IMT (Phase 3 regimen)	62 (44-80)	6 (2-13)	13.43 (1.8-30.3)	3.6 (1.8-16.5)	14%	61%
ASCENT (SG)	54 (27-82)	4 (2-17)	11.8	4.8	31%	40%
ASCENT (TPC)	53 (27-81)	4 (2-14)	6.9	1.7	4%	8%
TROPiCS-02 (SG)	57 (49-65)	3	14.4	5.5	21%	34%
TROPiCS-02 (TPC)	55 (48-63)	3	11.2	4	14%	22%

Bria-IMT was well-tolerated with no treatment-related discontinuations. 22% of patients are still in active survival follow up.

This analysis does not stratify Bria-IMT patients by hormone receptor or HER2 status, and the dataset reflects the information available at the time of abstract submission. Updated data will be shared during the company’s presentation at ASCO 2025.

PFS (median) and OS (median): Patients treated with Bria-IMT’s selected Phase 3 formulation (without IFNγ; N = 37) demonstrated significantly improved progression-free survival (3.6 vs. 2.6 months; P = 0.01) and overall survival (13.4 vs. 6.9 months; P = 0.01) compared to those who received the alternate formulation not advanced to Phase 3.

The overall survival observed in the Phase 3 formulation cohort (13.4 months) was comparable to that reported in the ASCENT (11.8 months) and TROPiCS-02 (14.4 months) studies and exceeded survival outcomes in their respective treatment of physician’s choice (TPC) arms (6.9 and 11.2 months).

BriaCell’s Phase 2 study also achieved a Clinical Benefit Rate (CBR) of 61%, outperforming ASCENT (40%) and TROPiCS-02 (34%), and an Objective Response Rate (ORR) of 14%, which matched or exceeded the TPC arms in both studies (4% and 14%).

Importantly, these outcomes were achieved in a more heavily pretreated patient population than those in the comparator trials—highlighting Bria-IMT’s strong anti-cancer activity. The favorable efficacy profile of the Phase 3 formulation supports its continued evaluation in BriaCell’s ongoing pivotal Phase 3 trial comparing Bria-IMT to treatment of physician’s choice (NCT06072612).

Abstract Title: Trial in progress: A study of Bria-OTS™ cellular immunotherapy in metastatic recurrent breast cancerSession Date and Time: June 2, 2025 9:00 AM-12:00 PM CDTAbstract Number for Publication: TPS1136Poster Board Number: 107aSession Type and Title: Poster Session – Breast Cancer—Metastatic

Heavily pre-treated MBC patients were treated in a dose escalation Phase 1/2 study of Bria-OTS monotherapy (single agent). The Phase 1 part of the study has enrolled and treated 3 patients. The first patient treated with single agent therapy has confirmed resolution of a breast cancer metastasis in the lung and remains on study.

Publish-Only Abstract Title: Impact of HLA Matching on Clinical Outcomes in a Phase 2 Trial of Bria-IMT Plus Anti PD1 in Advanced Breast Cancer

Following the presentations, copies of the presentations will be posted on https://briacell.com/scientific-publications/.

About BriaCell Therapeutics Corp.

BriaCell is a clinical-stage biotechnology company that develops novel immunotherapies to transform cancer care. More information is available at https://briacell.com/.

Safe Harbor

This press release contains “forward-looking statements” that are subject to substantial risks and uncertainties. All statements, other than statements of historical fact, contained in this press release are forward-looking statements. Forward-looking statements contained in this press release may be identified by the use of words such as “anticipate,” “believe,” “contemplate,” “could,” “estimate,” “expect,” “intend,” “seek,” “may,” “might,” “plan,” “potential,” “predict,” “project,” “target,” “aim,” “should,” “will,” “would,” or the negative of these words or other similar expressions, although not all forward-looking statements contain these words. Forward-looking statements, including those about BriaCell’s successful completion of the pivotal Phase 3 study supporting biologics license application, priority review, full approval, and commercialization; Bria-IMT’s potential to address the urgent, unmet needs of patients with metastatic breast cancer; BriaCell confirming results in their ongoing pivotal Phase 3 study; Bria-IMT being positioned as a promising, less toxic therapeutic option for patients battling metastatic breast cancer; BriaCell presenting at the 2025 American Society of Clinical Oncology and the contents of such presentations are based on BriaCell’s current expectations and are subject to inherent uncertainties, risks, and assumptions that are difficult to predict. Further, certain forward-looking statements are based on assumptions as to future events that may not prove to be accurate. These and other risks and uncertainties are described more fully under the heading “Risks and Uncertainties” in the Company's most recent Management’s Discussion and Analysis, under the heading "Risk Factors" in the Company's most recent Annual Information Form, and under “Risks and Uncertainties” in the Company's other filings with the Canadian securities regulatory authorities and the U.S. Securities and Exchange Commission, all of which are available under the Company's profiles on SEDAR+ at www.sedarplus.ca and on EDGAR at www.sec.gov. Forward-looking statements contained in this announcement are made as of this date, and BriaCell Therapeutics Corp. undertakes no duty to update such information except as required under applicable law.

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Contact Information

Company Contact:William V. Williams, MDPresident & CEO1-888-485-6340info@briacell.com 

Investor Relations Contact:investors@briacell.com