BriaCell's Phase 2 Trial Shows Promising Survival Rates in Metastatic Breast Cancer

Analysis reveals significant industry trends and economic implications

Release Date

2025-07-09

Category

Clinical Trial Event

Reference

Source

Breakthrough Clinical Results

BriaCell Therapeutics Corp. announced updated survival data from its Phase 2 clinical study of Bria-IMT in patients with metastatic breast cancer (MBC). The study showed a 52% one-year survival rate in a 25-patient cohort, exceeding current standard of care. Eleven patients remain alive, with two exceeding 30 months of survival. The treatment was well-tolerated, with no Bria-IMT-related discontinuations. These results, observed even in patients who failed prior treatments like checkpoint inhibitors and antibody-drug conjugates, highlight the potential of Bria-IMT, particularly in combination with CPIs, which is being investigated in an ongoing Phase 3 trial (NCT06072612).

Key Highlights

  • 52% one-year survival rate in a 25-patient Phase 2 cohort of metastatic breast cancer patients treated with Bria-IMT.
  • Survival benefit observed in heavily pre-treated patients, including those who failed checkpoint inhibitors and antibody-drug conjugates.
  • No treatment discontinuations attributed to Bria-IMT.
  • Ongoing Phase 3 trial (NCT06072612) investigating Bria-IMT in combination with CPIs.

Incidence and Prevalence

Global Epidemiology of Metastatic Breast Cancer

Breast cancer is the most prevalent cancer and the leading cause of cancer-related death among females worldwide. Despite all therapeutic advances, metastatic breast cancer is still associated with a median overall survival of 3 years. Metastasis is the main cause of death for patients with breast cancer, with Metastatic breast cancer (MBC) being associated with more than 90% of cancer-related deaths.

Global Distribution and Trends

Data from a comprehensive study covering 2.4 million women with breast cancer from 81 countries reveals significant geographical variations in metastatic breast cancer incidence:

  • The proportion of cases with distant metastatic breast cancer at diagnosis was high in sub-Saharan Africa, ranging from 5.6% to 30.6%
  • In contrast, this proportion was low in North America, ranging from 0.0% to 6.0%
  • Encouragingly, the proportion of patients diagnosed with distant metastatic disease decreased over the past 2 decades from around 3.8% to 35.8% (early 2000s) to 3.2% to 11.6% (2015 onwards)

Demographic Factors

Age and socioeconomic status significantly impact metastatic breast cancer diagnosis:

  • Older age had the largest proportion of cases diagnosed with distant metastatic stage ranging from 2.0% to 15.7% among the younger to 4.1% to 33.9% among the oldest age group
  • Lower socioeconomic status had the largest proportion of cases diagnosed with distant metastatic stage ranging from 1.7% to 8.3% in the least disadvantaged groups to 2.8% to 11.4% in the most disadvantaged groups

Regional Case Study: Mali

A specific study in Mali provides insight into metastatic breast cancer in a sub-Saharan African context:

  • A total of 231 cases of breast cancer were diagnosed
  • Among them, 60 cases were synchronous metastatic breast cancer (26%)
  • The mean age of metastatic breast cancer cases in Mali was 45.3 ±12.1 years old

Genomic and Biological Characteristics

The genomic landscape of metastatic breast cancer is enriched in clinically relevant genomic alterations and is more complex than that of early breast cancer. Metastatic breast cancers showed an increase in mutational burden and clonal diversity compared to early breast cancers.

In metastatic triple-negative breast cancers, there is an increase in the frequency of somatic biallelic loss-of-function mutations in genes related to homologous recombination DNA repair (7% versus 2% in early cases).

Prognostic Factors and Metastatic Sites

Bone metastasis is one of the causes that mainly decrease survival in patients with advanced breast cancer. Bladder metastases of solid neoplasms are rarely observed, with secondary bladder tumors originating from breast cancer occurring in 2.5% of cases in some series.

Cancer-associated fibroblasts (CAFs), which represent 80% of the fibroblasts present in the tumor microenvironment, are being studied as potential biomarkers. Proliferative CAFs (pCAFs) were found to dominate breast cancer with lymphatic node, bone, and brain metastasis. An increased proportion of pCAFs in advanced breast cancer was associated with a poor prognosis.

High CD105 expression in cancer-associated fibroblasts was associated with an increased risk of metastatic occurrence, particularly bone metastasis, as well as shorter metastasis-free survival, bone metastasis-free survival, and overall survival.

Emerging End Points

Based on PubMed publications within the last three years, the key endpoints for metastatic breast cancer (mBC) clinical trials are:

  • Overall Survival (OS): This remains the most important endpoint, representing the duration of life after diagnosis or treatment initiation. Patients value lengthened OS combined with no worsening or improvement in quality of life.
  • Quality of Life (QoL): QoL is a crucial endpoint, particularly in mBC, where treatment aims to prolong survival while maintaining a good quality of life. Patients prioritize therapies that improve or, at the very least, do not negatively impact their QoL. Aspects of QoL valued by mBC patients include relief from cancer-related symptoms, management of treatment-related toxicities, and the ability to pursue personal goals.
  • Progression-Free Survival (PFS): While OS and QoL are considered the most relevant endpoints, PFS, defined as the time without disease progression, is also meaningful to patients, especially when coupled with QoL improvements and minimal treatment toxicity. However, the clinical term "PFS" is often not well understood by patients, highlighting the need for patient-friendly language.

Clinical trials also consider the following:

  • Biologic Subtype and Line of Therapy: Endpoint selection should be tailored to the specific biologic subtype of mBC (e.g., hormone receptor-positive, HER2-positive, triple-negative) and the line of therapy (e.g., first-line, second-line). Different subtypes have varying prognoses and responses to treatment, necessitating subtype-specific endpoints.
  • Magnitude of Clinical Benefit: The magnitude of absolute and relative gains in OS and PFS that would represent a clinically meaningful benefit should be carefully considered when designing trials. This involves determining what degree of improvement is substantial enough to justify the potential risks and costs of a new therapy.

For example, in a phase 3 trial (TORCHLIGHT) evaluating toripalimab combined with nab-paclitaxel for advanced triple-negative breast cancer (TNBC), the primary endpoint was PFS, while overall survival was a secondary endpoint. The study demonstrated a statistically significant improvement in PFS in the PD-L1-positive population (median PFS 8.4 vs. 5.6 months). The median overall survival also improved (32.8 vs. 19.5 months). These findings suggest that the combination therapy offers a significant clinical benefit in this patient population.

Furthermore, research emphasizes the importance of patient perspectives in endpoint selection. Patients value periods of time without disease progression, especially when accompanied by improved QoL and no added toxicity. This underscores the need to incorporate patient preferences and priorities into the design and conduct of future clinical trials, as well as health technology assessment (HTA) and reimbursement decisions.

Bria-IMT Clinical Trials Beyond Metastatic Breast Cancer

Based on the available information, there is no data regarding Bria-IMT (SV-BR-1-GM) being investigated for clinical trials for any indications, including metastatic breast carcinoma.

The review of all input materials does not contain any information about:

  • Clinical trials of Bria-IMT for indications other than metastatic breast cancer
  • Any intervention models, protocols, or dosing regimens for Bria-IMT
  • Any therapeutic applications of Bria-IMT in oncological or non-oncological settings

Without specific information about Bria-IMT clinical trials in the provided context, no further details can be provided about its investigational status for any indications or the intervention models employed in such trials.