BCTX BriaCell Therapeutics Corporation

BriaCell Therapeutics Corp. (Nasdaq: BCTX, BCTXW) (TSX: BCT) (“BriaCell” or the “Company”), a clinical-stage biotechnology company that develops novel immunotherapies to transform cancer care, is pleased to report preliminary disease control rate of 61% in evaluable (i.e. exhibited clinical outcomes) Phase 2 advanced breast cancer patients treated with BriaCell’s Bria-IMT™ regimen – the same formulation being used in BriaCell’s open pivotal Phase 3 study. Additionally, a disease control rate of 50% was reported in similarly treated evaluable patients who had failed prior antibody-drug conjugate (ADC) therapy.

“We are extremely pleased to report clinical benefit with our regimen in a heavily pre-treated patient who had failed prior ADC treatment,” commented Dr. Giuseppe Del Priore, BriaCell’s Chief Medical Officer. “In addition to the longer than expected progression free and overall survival, we note the absence of serious complications such as potentially fatal interstitial lung disease (ILD) commonly associated with follow-on ADC treatments. The data supports the Bria-IMT™ approach as a promising therapeutic alternative to chemotherapy in advanced metastatic breast cancer.”

“We are beyond excited by the clinically significant disease control data we are seeing in this group of very difficult-to-treat patients,” stated Dr. William V. Williams, BriaCell’s President and CEO. “This data provides further encouragement to us as we continue our pivotal Phase 3 study enrollment. Our highest priority is to provide both survival and quality of life benefits to patients fighting a very deadly disease in a cohort with typically only a few months to live. Bria-IMT™ checks both boxes as no patients have discontinued our therapy due to treatment related serious side effects. We are closely monitoring the data and feedback we receive from our expert clinical team and the study participants, and look forward to sharing additional clinical data in the coming months.”

Case Report of a Notable Responder in Prior ADC Therapy Failure

Background: Advanced metastatic breast cancer patients who have had multiple lines of prior treatments including ADCs, are often recommended palliative, supportive medical care that focuses on easing pain, stress and other symptoms of a serious/terminal illness.

The patient was hormone receptor positive HER 2 negative (HR+/HER2-), had failed four prior lines of therapy including ADC therapy and had breast cancer metastasized to her liver. She had two HLA matches with Bria-IMT™ and received seven cycles of treatments with the Bria-IMT™ regimen.

Results: In her first on study assessment the liver metastasis was no longer seen. She had progression free survival (PFS) of 5.8 months, a 100% increase from her PFS on ADC therapy.

BriaCell Clinical Data in Evaluable Patients

Bria-IMT™ Combined with an Immune Check Point Inhibitor

Among the 35 patients with evaluable outcomes in BriaCell’s ongoing Phase 2 study, 23 patients were treated with the same Bria-IMT™ formulation currently being used in BriaCell’s Phase 3 metastatic breast cancer study. These patients had been heavily pre-treated and had failed a median number of six prior regimens.

Results in Evaluable Patients:

• Disease control rate of 61%; defined as the percentage of patients who achieve a complete response, partial response, or stable disease.
• Disease control rate of 50% in the 10 patient subset who had failed prior ADC therapy. This compares favorably with reported literature for second ADC treatment in ADC failure patients (~20-42%)1.
• Progression free survival of 4.2 months in ADC failure patients is also very favorable in comparison to published data in similar patients (1.6-3.3 months)1.
• No discontinuations due to drug toxicity reported.
• No cases of Interstitial Lung Disease (ILD) with Bria-IMT™ (a well-documented serious side effect of ADCs) reported in this group of patients.

The strong survival and clinical benefits observed in evaluable and ADC resistant patients support the use of the current formulation in BriaCell’s pivotal Phase 3 study and the Company looks forward to presenting further updates as treatment progresses in the fully enrolled Phase 2 study.

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 the Bria-IMT™ approach being a promising therapeutic alternative to chemotherapy in advanced metastatic breast cancer; BriaCell's ability to continue their ongoing pivotal Phase 3 study enrollment; BriaCell's Bria-IMT™ approach providing both survival and quality of life benefits to patients; BriaCell sharing additional clinical data with the public in the coming months; and BriaCell presenting further updates as treatment progresses in the fully enrolled Phase 2 study, 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.sedar.com 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 Information

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

Media Relations:Jules AbrahamCORE IRjulesa@coreir.com

Investor Relations Contact:CORE IRinvestors@briacell.com

1 Rachel Occhiogrosso Abelman, et al. Sequential use of antibody-drug conjugate after antibody-drug conjugate for patients with metastatic breast cancer: ADC after ADC (A3) study. Presented at ASCO 2023 Abstract 1022; Laura Huppert et al. Multicenter retrospective cohort study of the sequential use of the antibody-drug conjugates (ADCs) trastuzumab deruxtecan (T-DXd) and sacituzumab govitecan (SG) in patients with HER2-low metastatic breast cancer (MBC) (PS08-04) - SABCS 2023; François Poumeaud, et. al., Efficacy of Sacituzumab-Govitecan (SG) post Trastuzumab-deruxtecan (T-DXd) and vice versa for HER2low advanced or metastatic breast cancer (MBC): a French multicentre retrospective study. (PS08-02) - SABCS 2023