Dr. William Williams reports

BRIACELL ANNOUNCES STRONG CLINICAL DATA IN BREAST CANCER PATIENTS; REPORTS ANOTHER NOTABLE RESPONDER CASE

Briacell Therapeutics Corp. has released a preliminary disease control rate of 61 per cent in evaluable (that is, 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 per cent 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 pretreated 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 chief executive officer. "This data provides further encouragement to us as we continue our pivotal phase 3 study enrolment. 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-per-cent 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 continuing 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 pretreated and had failed a median number of six prior regimens.

Results in evaluable patients:

• Disease control rate of 61 per cent -- defined as the percentage of patients who achieve a complete response, partial response or stable disease.
• Disease control rate of 50 per cent in the 10-patient subset who had failed prior ADC therapy. This compares favourably with reported literature for second ADC treatment in ADC failure patients (approximately 20 per cent to 42 per cent).
• Progression-free survival of 4.2 months in ADC failure patients is also very favourable in comparison with published data in similar patients (1.6 months to 3.3 months).
• No discontinuations due to drug toxicity reported.
• No cases of interstitial lung disease 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.

We seek Safe Harbor.