Dr. William Williams reports

BRIACELL PRESENTS POSITIVE PHASE 3 QUALITY OF LIFE AND PHASE 2 BIOMARKER DATA AT THE 2026 AACR MEETING

Briacell Therapeutics Corp. is presenting positive data in three clinical posters at the 2026 American Association for Cancer Research (AACR) annual meeting, taking place April 17 to April 22 at the San Diego Convention Center in San Diego, Calif. The presentations will include one poster featuring data from Briacell's continuing pivotal phase 3 study of Bria-IMT plus an immune checkpoint inhibitor and two posters highlighting further analyses of phase 2 data. Abstracts will be published in the on-line proceedings of the AACR.

• Phase 3 clinical data in heavily pretreated metastatic breast cancer patients with prior failed ADC, CPI and CDK4/6 inhibitor treatments shows quality of life (QOL) largely preserved.
• Identification of potential prognostic biomarkers upon further analyses of phase 2 Bria-IMT study data.
• Bria-OTS+ in Preclinical Cancer Models to be presented on Tuesday, April 21, from 2 p.m. to 5 p.m. PT; poster No.: 6701.

"Standards of care in cancer are evolving rapidly as innovative immunotherapy approaches emerge with potentially better safety profiles than chemotherapy. Clinical data, including Briacell's, highlight that maintaining quality of life is an important treatment goal alongside efficacy and safety," stated lead author, Saranya Chumsri, MD, principal investigator of Briacell phase 3 study of Bria-IMT+CPI, and professor of oncology, Mayo Clinic.

"At Briacell, we are focused on bringing novel therapeutics to cancer patients with unmet medical needs with the ultimate goal of improving patients' lives," noted William V. Williams, MD, Briacell's president and chief executive officer. "Our new quality of life data from the phase 3 Bria-IMT plus CPI study in patients with metastatic breast cancer who failed prior therapies show very positive trends, bringing us one step closer to transforming care for these patients."

Session title:  Phase II and Phase III Clinical Trials

Session:  April 20, 2026, 2 p.m. to 5 p.m. PT

Location:  Poster Section 52

Poster board No.:  1

Poster No.:  CT137

Title:  QOL Outcomes in Bria-ABC Late-Stage Metastatic Phase 3 Trial

Summary:  Heavily pretreated metastatic breast cancer patients in the pivotal phase 3 study of Bria-IMT plus an immune check point inhibitor maintained overall health status and key functional measures with a favourable safety profile. These findings are encouraging because they suggest meaningful preservation of quality of life for late-stage metastatic breast cancer patients with limited treatment options.

• QOL largely preserved in a heavily pretreated population with prior antibody-drug conjugate (ADC), check point inhibitor (CPI) and cyclin-dependent kinase 4/6 (CDK4/6) inhibitor exposure.
• European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 Survey showed:
  • 1) Global health status stable through early and mid-treatment;
  • 2) Emotional and cognitive functioning maintained; symptom burden stable.
• Safety profile and time-to-deterioration analyses support durable tolerability in a late-line setting.
• Briacell clinical data supports feasibility of decentralized treatment approaches, including potential home self-administration strategies.

Session category:  clinical research

Session:  April 19, 2026, at 2 p.m. to 5 p.m. PT

Location:  Poster Section 42

Poster board No.:  5

Poster No.:  1065

Title:  Mitosis in Circulating Tumor Cells Correlates with Highly Aggressive Disease in Metastatic Breast Cancer

Summary:  Circulating tumour cells (CTCs) are a well-established non-invasive blood-based biomarker that can help stratify prognosis in patients with metastatic breast cancer (MBC), particularly in aggressive disease subtypes. Early pilot studies had identified a distinct subset of CTCs undergoing mitosis (dividing cells), whose presence appeared to correlate with worse survival outcomes. However, their prognostic significance and potential interaction with different treatment regimens have not been clinically evaluated. In this multi-institutional prospective study, patients with mitotic CTCs were found to have poorer outcomes than those with non-mitotic CTCs or no CTCs, but appeared to have overall survival benefit when treated with targeted therapy. Over all, these findings support mitotic CTCs as a novel potential prognostic biomarker in metastatic breast cancer.

Session category:  clinical research

Session title:  Biomarkers Predictive of Therapeutic Benefit 1

Session:  April 19, 2026, at 2 to 5 p.m. PT

Location:   Poster Section 40

Poster board No.:   19

Poster No.:  1025

Title:  Monitoring PD-L1 in tumor macrophage fusion cells in blood identifies high PD-L1 checkpoint inhibitor responses in metastatic breast cancer

Summary:  Tissue biopsy PD-L1 combined positive score (CPS greater than or equal to 10) has been identified as a positive prognostic marker in metastatic breast cancer. However, a significant percentage of MBC patients with CPS less than 10 seem to benefit from immune check point inhibitor (ICI) therapy. Circulating tumour-macrophage fusion cells (TMFCs) express PD-L1 and changes in TMFC PD-L1 expression during ICI treatment may explain this outcome. This phase 2 prospective study found no correlation between tumour PD-L1 CPS and clinical response while demonstrating that patients with PD-L1 positive TMFCs in their blood had significantly improved progression free survival. Monitoring PD-L1 in TMFCs may serve as a real-time biomarker to better indicate ICI response and further studies into the role of TMFC PD-L1 in predicting therapeutic response are continuing.

Following the presentation, copies of the posters will be made available at the company's website.

About Briacell Therapeutics Corp.

Briacell is a clinical-stage biotechnology company that develops novel immunotherapies to transform cancer care.

We seek Safe Harbor.