BriaCell Showcases Data Demonstrating Unmatched Progression-Free Survival (PFS) and Clinical Efficacy in Antibody-Drug Conjugate (ADC) Resistant and Central Nervous System (CNS) Metastatic Breast Cancer at the 2024 AACR

• PFS of 4.2 months in Phase 2 ADC resistant patients receiving Bria-IMT™ pivotal Phase 3 formulation is twice that of controls in similar studies
• PFS results reinforced by larger number of prior treatments in Bria-IMT™ population than in comparable studies
• Bria-IMT™ PFS compares favorably to their most recent treatment PFS in 48% of patients
• Clinical benefit rate of 56% in evaluable patients
• 71% intracranial objective response rate (iORR) in heavily pretreated patients
• Findings support clinical efficacy of Bria-IMT™ and highlight its significant potential in managing CNS metastatic disease in advanced breast cancer
• Additional preclinical anti-cancer data of Bria-OTS+™ and Bria-PROS+™ will be presented tomorrow 9:00 AM – 12:30 PM PST; Abstract Presentation Number: 6753

PHILADELPHIA and VANCOUVER, British Columbia, April 09, 2024 (GLOBE NEWSWIRE) — 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 presenting positive clinical data from its lead product candidate, Bria-IMT™, in two posters of its three poster sessions during the 2024 American Association for Cancer Research (AACR) Annual Meeting held from April 5-10 at San Diego Convention Center, San Diego, CA.

“We are extremely impressed by the unprecedented survival and clinical benefit data for Bria-IMT™ in patients who have failed ADCs,” stated lead author Chaitali S. Nangia, MD, Partner at Hoag Medical Group. “ADCs are the latest treatments for very difficult-to-treat advanced metastatic breast cancer. However, some patients experience resistance with rapid disease progression. To our knowledge, there are no effective treatment options in this patient population for whom the progression-free survival prognosis is only a few weeks. Finding an alternative well-tolerated treatment option that is effective is a matter of life and death for these patients.”

“Our clinical data further validates Bria-IMT™’s novel mechanism of action to generate potent immune responses in breast cancer patients who failed ADCs leading to clinically relevant survival and treatment benefit in these patients,” commented Dr. Giuseppe Del Priore, BriaCell’s CMO. “We look forward to building upon the body of evidence with additional clinical data in the coming months from the ongoing pivotal registration trial.”

“We are excited about the safety and efficacy data to date with Bria-IMT™ and expect that Bria-IMT™ will generate positive effects on survival and clinical benefit in the Phase 3 study in advanced breast cancer patients whose medical needs remain unmet,” commented Dr. William V. Williams, BriaCell’s President and CEO.

The posters are summarized below and linked here: https://briacell.com/scientific-publications/.

Poster 1 – Title: Efficacy of Bria-IMT™ regimen in inducing CNS metastasis regression
Abstract Presentation Number: CT204

Superior clinical benefit of Bria-IMT™ regimen – alone or combined with an immune check point inhibitor (CPI) in advanced breast cancer patients with CNS metastatic disease

• Clinical efficacy: 71% (5/7) intracranial objective response rate (iORR), defined as the percentage of patients who achieve a complete response (complete disappearance) or partial response (volume reduction of 30% or more) in intracranial tumors, achieved in patients with central nervous system (CNS) metastases treated with the Bria-IMT™ regimen, either alone or in combination with an immune checkpoint inhibitor (i.e. PD-1 inhibitor pembrolizumab or retifanlimab). These patients failed multiple prior treatments including 2 antibody-drug conjugates in one case. Clinical benefit is observed across all subsets of breast cancer.
• Safety profile: Absence of both interstitial lung disease (ILD), a common serious adverse event with ADCs, and no Bria-IMT™-related treatment discontinuations underscore Bria-IMT™’s excellent tolerability and favorable safety profile.

In summary, Bria-IMT™’s tumor reductions observed in all breast cancer subtypes in patients with intracranial disease underlines its potential clinical effectiveness in managing CNS metastatic disease in advanced breast cancer. BriaCell will continue to monitor the data in this subgroup of patients including a pre-planned subgroup analysis in the current pivotal Phase 3 study in advanced metastatic breast cancer. Treatment of patients with CNS metastatic disease represents a potential additional indication for market approval of Bria-IMT™.

Poster 2 – Title: Efficacy and safety of SV-BR-1-GM after progression on ADC in metastatic breast cancer patients
Abstract Presentation Number: CT206

Notable progression-free survival benefit of Bria-IMT™ in ADC resistant advanced metastatic breast cancer

Phase 2 clinical data of the Bria-IMT™ regimen in 23 advanced metastatic breast cancer patients who failed multiple prior treatments including ADCs and CPIs (median of 6 prior treatments) are presented.

• Progression-free Survival Benefit: Median progression free survival (PFS), defined as the length of time during which a patient’s cancer does not get worse, in heavily pre-treated patients of 3.5 months is comparable to that seen in similar studies in patients with a history of fewer prior treatments (median of 4)^1,2. Similarly, median PFS of 4.2 months in patients receiving the Bria-IMT™ pivotal phase 3 formulation is approximately twice the PFS figures reported for treatment of physician’s choice (TPC) in other similar studies. These PFS results suggest superior clinical efficacy considering the larger number of prior treatments in Bria-IMT™ patients vs those of the other studies.
• Clinical efficacy: PFS is similar or better than that of the last regimen in 48% (11/23) of the patients suggesting Bria-IMT™ effectiveness in delivering clinical and survival benefits in these patients. Additionally, a clinical benefit rate (CBR), defined as percentage of patients whose disease shrinks or remains stable over a certain time, of 56% is observed in evaluable patients further highlighting clinical benefit.
• Subset specific clinical benefits: Study data to date suggests clinical benefit for multiple breast cancer subtypes including HR+/HER2- (the most common breast cancer subtype, testing positive for estrogen and/or progesterone receptors and negative for human epidermal growth factor receptor 2 or HER2) with a CBR following treatment, of 63% (5 of 8 patients); HER2+ subtype (a positive test for HER2) with a 100% CBR (2 of 2 patients) and HR-/HER2 low subtype (a negative test for estrogen and/or progesterone receptor and a negative test for HER2) showing a CBR of 66% (2 of 3 patients).
• Safety profile: There are no incidents of interstitial lung disease – a well-documented serious adverse event associated with ADCs, – in either ADC naïve or ADC treated patients, and no treatment-related discontinuations of Bria-IMT™.

In summary, the data to date shows that Bria-IMT™ provides prolonged progression-free survival and clinical benefits in heavily pre-treated, ADC resistant breast cancer patients compared with those in other similar studies. BriaCell will be monitoring ADC resistant patients in its ongoing pivotal Phase 3 study of Bria-IMT™ and CPI in advanced metastatic breast cancer.

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_{¹ Cortes J et al. Eribulin monotherapy versus treatment of physician’s choice in patients with metastatic breast cancer (EMBRACE): a phase 3 open-label randomized study. Lancet (2011) 377: 914–23
² Bardia A et al. Final results from the randomized phase III ASCENT clinical trial in metastatic triple-negative breast cancer and association of outcomes by human epidermal growth factor receptor 2 and trophoblast cell surface antigen 2 expression. J Clin Oncol (2024) 00:1-7}

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 presenting three posters at the 2024 AACR, and the contents of such posters; the positive clinical data from BriaCell’s Bria-IMT™ being presented in two posters during the 2024 AACR; the clinical efficacy of Bria-IMT™ and its potential clinical effectiveness in managing CNS metastatic disease in advanced breast cancer; the unprecedented survival and clinical benefit data for Bria-IMT™; Bria-IMT™’s ability to generate potent immune responses in breast cancer patients who failed ADCs, leading to clinically relevant survival and treatment benefit; BriaCell’s ability to build upon their current body of evidence with additional clinical data in the coming months from the ongoing registration trial; Bria-IMT™’s ability to generate positive effects on survival and clinical benefit in the Phase 3 study in advanced breast cancer patients; Bria-IMT™’s tolerability and favorable safety profile; Bria-IMT™’s significant potential in managing CNS metastatic disease in advanced breast cancer; BriaCell monitoring the data in a subgroup of patients including a pre-planned subgroup analysis in the current pivotal Phase 3 study in advanced metastatic breast cancer; the treatment of patients with CNS metastatic disease representing a potential additional indication for market approval of Bria-IMT™; Bria-IMT™’s effectiveness in delivering clinical and survival benefits in patients; the Bria-IMT™ data representing a clinical benefit for multiple breast cancer subtypes including HR+/HER2; and BriaCell’s monitoring of ADC resistant patients in their ongoing pivotal Phase 3 study of Bria-IMT™ and CPI in advanced metastatic breast cancer, 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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Contact Information

Company Contact:
William V. Williams, MD
President & CEO
1-888-485-6340
info@briacell.com 

Media Relations:
Jules Abraham
CORE IR
julesa@coreir.com

Investor Relations Contact:
CORE IR
investors@briacell.com