Dr. William Williams reports

BRIACELL ANNOUNCES RESOLUTION OF LUNG METASTASIS IN FIRST PATIENT TREATED WITH BRIA-OTS; LUNG METASTASIS (FROM METASTATIC BREAST CANCER) RESOLVED - AFTER ONLY 2 MONTHS (4 DOSES) OF TREATMENT WITH BRIA-OTS MONOTHERAPY; NO TOXICITY RELATED TO THE TREATMENT; PATIENT REMAINS ON STUDY

Briacell Therapeutics Corp. has released data showing an unprecedented clinical response including resolution of a lung metastasis (breast cancer tumour that spread to the lung) with stable disease elsewhere. This patient is the first metastatic breast cancer (MBC) patient treated with Bria-OTS.

Bria-OTS is a personalized off-the-shelf immunotherapy, currently under investigation in a phase 1/2a dose escalation study (U.S. ClinicalTrials identifier: NCT06471673) in metastatic recurrent breast cancer. Bria-OTS represents a personalized, next-generation, advancement of Briacell's lead candidate Bria-IMT which is currently in a pivotal phase 3 study for metastatic breast cancer. Images available on the company's website show treatment with Bria-OTS monotherapy resulted in 100-per-cent resolution of tumour in the lung of the MBC patient following four injection cycles. (The other white dots in the lungs are blood vessels.)

The lesion in the patient's right lung (left side of the image) is no longer detectable on the images taken two months after treatment with Bria-OTS monotherapy.

This 78-year-old woman with metastatic breast cancer (hormone receptor positive, HER2 negative) had failed several prior lines of therapy and received the lowest dose level in the phase 1/2a Bria-OTS study. At enrolment on Nov. 21, 2024, she had extensive metastases including multiple bone, lymph node and lung metastases. Following four injections with Bria-OTS every two weeks, the lung metastasis completely resolved, and she had stable disease elsewhere.

"Despite recent advancements in cancer treatment with antibody-drug-conjugates (ADCs) and immune checkpoint inhibitors (CPIs), metastatic breast cancer remains an unmet medical need as many patients do not respond to these treatments," stated Dr. Neal Chawla, associate director of clinical research at the Sarcoma Oncology Center and principal investigator for the Bria-OTS study. "We are very impressed by the clinical response observed showing rapid and robust clinical activity in addition to excellent tolerability in the first patient treated with Bria-OTS and look forward to reproducing these results in other cancer patients in the study."

"This data supports our hypothesis of personalized immunotherapy with Bria-OTS, potentially leading to new and effective treatment of metastatic breast cancer," stated Dr. William V. Williams, Briacell's president and chief executive officer. "We hope to transform the way we treat cancer patients with our novel personalized off-the-shelf immunotherapy approach."

"Resolution of metastatic lung disease in this breast cancer patient highlights the clinical effectiveness of Bria-OTS, and its therapeutic potential in MBC," commented Dr. Giuseppe Del Priore, Briacell's chief medical officer. "This result represents a major step towards advancing our innovative technology platform and our goal of offering safe and effective treatment to MBC patients and our plans to extend into prostate cancer, melanoma and lung cancer."

The phase 1/2a clinical trial is initially evaluating the safety and efficacy of Bria-OTS as monotherapy and, later, in combination with an immune checkpoint inhibitor in metastatic breast cancer. Key inclusion criteria include recurrent metastatic breast cancer and at least two failed prior attempts of systemic therapy (that is, chemotherapy). The study design includes a dose escalation monotherapy phase followed by an expansion phase that will include combination therapy with an immune checkpoint inhibitor.

About Briacell Therapeutics Corp.

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

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