An investigational vaccine for triple-negative breast cancer (TNBC) has shown encouraging results in a Phase 1 trial, with over 70% of patients exhibiting immune responses, according to findings presented at the Society for Immunotherapy of Cancer (SITC) 39th Annual Meeting. The study, conducted in collaboration with Cleveland Clinic and funded by the US Department of Defense, evaluated the safety and immunogenicity of the α-lactalbumin vaccine.
Phase 1 Trial Details
The Phase 1 trial (NCT04674306) involved three patient cohorts. Cohort 1a included 21 women previously treated for TNBC, cohort 1b included 2 women at high genetic risk of TNBC undergoing prophylactic mastectomies, and cohort 1c consisted of 3 patients with TNBC receiving the vaccine alongside pembrolizumab (Keytruda). The primary endpoint was to evaluate the maximum tolerated dose (MTD), while secondary endpoints aimed to determine the lowest immunologic dose of the vaccine.
The vaccine was administered in three doses, two weeks apart. Dose-limiting toxicities, defined as grade 2 or worse adverse events, were closely monitored to prioritize safety.
Safety and Immune Response
The α-lactalbumin vaccine demonstrated a favorable safety profile, with injection site irritation being the most common adverse event. No major systemic adverse events were observed, even when the vaccine was administered in combination with pembrolizumab. The maximum tolerated dose has been identified, and alternative dose combinations are under investigation.
In cohort 1a, the vaccine was safe and tolerable, with strong immune responses noted. A similar safety profile was observed in cohort 1b, with enrollment and tissue analysis ongoing. Cohort 1c showed no major adverse events from the combination therapy, and confirmed immune responses were observed. According to the trial, nearly 75% of women treated with the vaccine achieved an immune response.
Azka Ali, MD, medical oncologist at Cleveland Clinic, noted, "This continues to be encouraging work. The goal of these exploratory assays and the extension of preclinical work is to make sure that what we are doing with the vaccine is eliciting an immune response. That immune response could ultimately predict vaccine activity."
Future Directions
Based on these promising results, a Phase 2 trial is planned to commence in 2025. This trial will evaluate the vaccine's effectiveness in the neoadjuvant setting for patients with newly diagnosed breast cancer. Researchers also plan to conduct further preclinical work to better understand the vaccine's mechanism of action and identify potential biomarkers for predicting response.
Amit Kumar, PhD, chairman and chief executive officer of Anixa Biosciences, stated, "We are pleased with the data we have observed in this clinical trial. As we near completion of the phase 1 trial, with the very positive data to date, we are planning a phase 2 study which is expected to commence in 2025."
The long-term goal is to develop a preventive vaccine that can be administered to individuals at high risk of developing TNBC. G. Thomas Budd, MD, of Cleveland Clinic's Cancer Institute, emphasized the need for more effective treatments for TNBC, stating, "Long term, we are hoping that this can be a true preventive vaccine that would be administered to individuals who are cancer-free to prevent them from developing this highly aggressive disease."
Background on Triple-Negative Breast Cancer
TNBC is an aggressive form of breast cancer that lacks estrogen receptors, progesterone receptors, and HER2 amplification, making it difficult to treat with traditional hormone therapies and HER2-targeted agents. It accounts for approximately 10-15% of all breast cancers and disproportionately affects younger women and women of African descent. The current standard of care for early-stage TNBC involves chemotherapy, and in some cases, immunotherapy. However, recurrence rates remain high, highlighting the need for novel therapeutic strategies.
