BriaCell and BriaPro to Present Preclinical Anti-Cancer Activity and Immunotherapy Findings at SITC 2026

• Four presentations highlight BriaCell’s Bria-OTS+™ cellular immunotherapy platform and BriaPro’s CD80-based immunotherapy programs

• In vitro Bria-OTS+ studies demonstrate immune-cell activation and tumor-cell killing across breast, prostate and lung cancer models

• BriaPro data describes BP-80 tolerability in nonhuman primates and engineered CD80 constructs with enhanced PD-L1 binding

PHILADELPHIA and VANCOUVER, British Columbia, Nov. 03, 2026 (GLOBE NEWSWIRE) -- BriaCell Therapeutics Corp. (Nasdaq: BCTX, BCTXL) (TSX: BCT) (“BriaCell” or the “Company”), a clinical-stage biotechnology company developing novel immunotherapies to transform cancer care, and its majority-owned subsidiary, BriaPro Therapeutics Corp. (“BriaPro”), today announced four preclinical research presentations at the Society for Immunotherapy of Cancer (SITC) 41th Anniversary Annual Meeting, taking place November 4-8, 2026, in Phoenix, AZ.

The presentations cover BriaCell’s personalized off-the-shelf immunotherapy platform, Bria-OTS+, and three BriaPro research programs: BP-80, a soluble CD80-Fc fusion protein; TILsRx-001, a tumor-targeted CD80-based checkpoint inhibitor; and engineered CD80 variants with altered immune receptor binding.

“The Bria-OTS+ studies demonstrate immune-cell activation and tumor-cell killing in laboratory models spanning breast, prostate and lung cancers,” said Miguel A. Lopez-Lago, PhD, BriaCell’s Chief Scientific Officer. “These findings support continued investigation of the platform, including how its immune responses may translate into clinical activity, potentially providing more durable and effective cancer immunotherapies.”

“The four presentations provide additional preclinical data supporting our cellular and protein-based immunotherapy research,” stated William V. Williams, MD, BriaCell’s President and CEO. “We are advancing the clinical evaluation of our Bria-OTS+ programs while continuing preclinical development of BriaPro’s candidates.”

Presentation abstract summaries are listed below.

Title: A Multifaceted Genetically Engineered Whole-Cell Vaccine Platform Generates Potent, Broad, Persistent, and Effector-Centric Anti-Tumor Immunity Across Multiple Cancer Indications Abstract Number: 863 Location: PCC-North Building-Lower Level-Exhibition Halls 4-5-6 Date: Friday, Nov. 6, 2026

Summary: Bria-OTS+ is a modular allogeneic whole-cell vaccine platform engineered to combine tumor-derived antigens, immune-stimulatory cytokines, co-stimulatory molecules, and diverse HLA antigens. Bria-OTS+ activated innate and adaptive immune cells, including dendritic, NK, NKT, CD4+ T, and CD8+ T cells, represented by increased activation markers, cytokine production, proliferation, and cytotoxicity. Bria-OTS+ also induced immune activation in PBMCs obtained from cancer patients, extending these findings beyond healthy-donor models.

In vitro studies showed that Bria-OTS+ stimulated innate and adaptive immune responses, broad tumor recognition, sustained cytotoxicity, and memory-like responses across breast, prostate, and lung cancer models, supporting its potential as a broadly applicable cancer immunotherapy platform.

Title: Development of BP-80, a soluble CD80 dimer (CD80-Fc) for cancer treatment Abstract Number: 404 Location: PCC-North Building-Lower Level-Exhibition Halls 4-5-6 Date: Saturday, Nov. 7, 2026

Summary: BP-80 is a soluble CD80-Fc fusion protein incorporating the full wild-type CD80 extracellular domain, designed to promote T cell activation through CD28 co-stimulation and counteracting CTLA-4-mediated inhibition. Its Fc region contains L234A/L235A (LALA) mutations to reduce antibody-dependent effector functions. In cell-based assays, BP-80 demonstrated CD28 co-stimulatory activity and counteracted CTLA-4-mediated inhibition, with activity dependent on Fc receptor engagement and anti-Fc antibody-based crosslinking, respectively. In cynomolgus monkeys, BP-80 demonstrated a no observed effect level (NOEL) of 50 mg/kg/day and a half-life ranging from 8.08 to 8.92 hours.

Title: Tumor-targeted checkpoint inhibitors for reactivation of tumor-infiltrating lymphocytes Abstract Number: 405 Location: PCC-North Building-Lower Level-Exhibition Halls 4-5-6 Date: Friday, Nov. 6, 2026

Summary: TILsRx-001 is a tumor-targeted, tetravalent immune checkpoint inhibitor comprising an engineered CD80 extracellular domain with enhanced PD-L1 affinity and an anti-B7-H3 single-chain variable fragment (scFv) for tumor targeting. In a cell-based study, TILsRx-001 antagonized the immune inhibitory effect of PD-L1 expressed on cells co-expressing B7-H3, supporting further investigation of targeted checkpoint inhibition to enhance tumor-infiltrating lymphocyte (TIL) activity.

Title: Molecular design of CD80 variants with increased affinity for PD-L1 and wild-type or lower affinity for CD28 Abstract Number: 406 Location: PCC-North Building-Lower Level-Exhibition Halls 4-5-6 Date: Saturday, Nov. 7, 2026

Summary: CD80 (B7-1) regulates T cell activity through interactions with CD28, PD-L1, and CTLA-4. Structure-guided protein engineering identified CD80 variants with increased PD-L1 binding affinity and minimal effect on CD28 affinity, a potential approach to limiting excessive T cell stimulation. One variant demonstrated more than 130-fold stronger PD-L1 binding than wild-type CD80 (0.23 µM versus >30 µM). Another mutation increased CTLA-4 affinity approximately fivefold while preserving CD28 affinity. These findings support further development of engineered CD80 proteins for cancer immunotherapy.

BriaCell is an immuno-oncology-focused biotechnology company developing targeted and effective approaches for the management of cancer. More information is available at https://briacell.com/.

BriaPro is a pre-clinical stage immunotherapy company developing binding agents and proteins with the intention to boost the ability of the body’s own cancer-fighting cells to destroy cancerous tumors.

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 and BriaPro presenting posters at the SITC 2026 Annual Meeting, and the contents of such posters, 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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