<div id="readability-page-1"><div><ul><li>Bria-OTS has cleared its safety evaluation in the Phase 1/2 study monotherapy dosage setting</li><li>Phase 1/2 study has now transitioned to dosing patients in combination with checkpoint inhibitor in metastatic breast cancer </li><li>First Bria-OTS monotherapy patient remains on study with confirmed resolution of lung metastasis</li></ul>PHILADELPHIA and VANCOUVER, British Columbia, May 27, 2025 (GLOBE NEWSWIRE) — BriaCell Therapeutics Corp. (Nasdaq: BCTX, BCTXW, BCTXZ; TSX: BCT), a clinical-stage biotechnology company advancing personalized immunotherapies for cancer, today announced that Bria-OTS has cleared its safety evaluation in the Phase 1/2 monotherapy study and has now transitioned to dosing patients in combination with a checkpoint inhibitor (CPI). The first patient has been dosed in the checkpoint inhibitor combination cohort of the ongoing Phase 1/2 study of Bria-OTS (NCT06471673) in metastatic breast cancer.Bria-OTS, a personalized next-generation version of Bria-IMT™—currently in a pivotal Phase 3 trial—is designed to enhance immune responses against tumors. The CPI combination cohort follows the successful completion of a three-patient monotherapy safety run-in. Notably, the first monotherapy patient remains on study with complete resolution of lung metastasis.“The encouraging responses seen will give us reason to believe that combining Bria-OTS with a checkpoint inhibitor could yield even greater anti-tumor activity,” said Neal S. Chawla, MD, Director at the Sarcoma Oncology Center, Santa Monica, Ca., and Principal Investigator for the Bria-OTS study. “This approach may offer a new option for patients who have not responded to existing to antibody-drug-conjugates (ADCs) or checkpoint inhibitors. We are excited to further explore the therapeutic potential of the Bria-OTS platform.”“Initiating the CPI combination cohort marks a significant milestone for BriaCell,” added Dr. William V. Williams, BriaCell’s President and CEO. “We believe Bria-OTS has the potential to address major gaps in current cancer care, and this step brings us closer to offering a much-needed personalized immunotherapy for difficult-to-treat cancers.”The ongoing study will assess Bria-OTS in combination with a CPI in up to 12 patients with metastatic breast cancer, with safety and objective response rate (ORR) as primary endpoints. BriaCell also plans to evaluate Bria-OTS+™, a further optimized version of the platform, across multiple cancer types including breast and prostate cancers.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 HarborThis 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 include: the belief that combining Bria-OTS with a checkpoint inhibitor could yield even greater anti-tumor activity; the Bria-OTS approach offering a new option for patients who have not responded to existing to antibody-drug-conjugates (ADCs) or checkpoint inhibitors; BriaCell further exploring the therapeutic potential of the Bria-OTS platform; Bria-OTS having the potential to address major gaps in current cancer care and offering a personalized immunotherapy for difficult-to-treat cancers; the ongoing study assessing Bria-OTS in combination with a CPI in up to 12 patients with metastatic breast cancer, with safety and objective response rate (ORR) as primary endpoints; and BriaCell planning to evaluate Bria-OTS+ across multiple cancer types including breast and prostate cancers. Forward-looking statements 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. 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.Neither the Toronto Stock Exchange nor its Regulation Services Provider (as that term is defined in the policies of the Toronto Stock Exchange) accepts responsibility for the adequacy or accuracy of this release.Contact InformationCompany Contact:William V. Williams, MDPresident &amp; CEO1-888-485-6340info@briacell.com Investor Relations Contact:investors@briacell.com</div></div>

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BriaCell Therapeutics Corp. has announced that its Bria-OTS treatment has cleared safety evaluations in a Phase 1/2 study and has begun dosing patients in combination with a checkpoint inhibitor for metastatic breast cancer. The first patient in this cohort has been dosed, following a successful monotherapy safety run-in. The study aims to assess the safety and efficacy of Bria-OTS combined with a CPI, potentially offering new options for patients unresponsive to current treatments. BriaCell plans to further evaluate its platform across various cancer types.

BriaCell Bria-OTS™ Phase 1/2 Study Clears Safety Evaluation; Doses First Patient in Combination with Checkpoint Inhibitor