Scientists stunned: New vaccine shows hope against deadliest breast cancer

In what researchers are calling a potentially transformative development for breast cancer care, an experimental vaccine targeting triple-negative breast cancer (TNBC) has shown encouraging results in early clinical testing.

This class of breast cancer, aggressive and often resistant to standard hormone or HER2-based therapies, has long posed one of oncology’s greatest therapeutic challenges. Early clinical data suggesting that a vaccine could stimulate the immune system to recognise and slow the disease represents a major advance.Anixa Biosciences (ANIX), a biotechnology firm focused on developing cancer vaccines and therapeutics, has announced the full Phase 1 results of its investigational breast cancer vaccine, unveiled at the 2025 San Antonio Breast Cancer Symposium. Developed in partnership with Cleveland Clinic and funded by the US Department of Defense, the vaccine achieved all primary endpoints in the early-stage trial.According to the company, the candidate was safe, well tolerated at the highest tested dose and triggered measurable immune responses in 74% of participants. The study targeted triple-negative breast cancer (TNBC), one of the most aggressive and difficult-to-treat forms of the disease.Dr Justin Johnson, who presented the findings, emphasized that demonstrating safety and immune activation is a crucial early milestone. Dr G Thomas Budd added that the results support advancing the alpha-lactalbumin vaccine into later-phase trials.

“Triple-negative breast cancer remains one of the most challenging forms of the disease to treat effectively,” said Dr G Thomas Budd, MD, principal investigator at Cleveland Clinic’s Cancer Institute. “These early results are encouraging—not only is the vaccine safe, but it also triggered immune responses in more than 70% of participants.”

Why triple-negative breast cancer is so challenging

TNBC accounts for approximately 10–15% of all breast cancers and is defined by the absence of oestrogen receptors, progesterone receptors and HER2 protein.

Due to this “triple negative” profile, conventional targeted therapies are not effective. Patients are commonly treated with chemotherapy, radiation and surgery but recurrence rates remain high and outcomes poorer compared to other breast cancer subtypes.

How the experimental vaccine works

Rather than directly killing cancer cells like chemotherapy, the vaccine aims to train the patient’s immune system to recognise and attack cancer cells.

Most investigational vaccines for TNBC are designed to present specific cancer-associated proteins (antigens) to immune cells, prompting them to mount a targeted antitumor response.This strategy is part of a broader push in oncology to harness the body's own defences, a trend that has already revolutionised treatment in melanoma and lung cancer. The vaccine is based on pioneering research by the late Vincent Tuohy, PhD, former Mort and Iris November Distinguished Chair in Innovative Breast Cancer Research at Cleveland Clinic.

His work identified α-lactalbumin, a protein present during lactation but absent in healthy breast tissue afterward, as a target.However, α-lactalbumin reappears in most TNBC tumours. The vaccine is designed to train the immune system to recognise this protein and attack emerging cancer cells.Dr Tuohy’s pre-clinical research, funded in part by more than 20,000 philanthropic donors over 12 years, demonstrated that vaccinating against α-lactalbumin prevented breast tumors in mice, a breakthrough published in Nature Medicine.“It was Dr Tuohy’s vision that immunisation could offer a new way to fight breast cancer,” said Justin Johnson, PhD, who presented the study. “Seeing immune responses across all three patient cohorts is a strong signal that this approach holds real promise.”

Inside the Phase 1 trial

Funded by the US Department of Defense and conducted in partnership with Anixa Biosciences, the study evaluated safety and immune response. A total of 35 participants were enrolled across three cohorts:

Launched in 2021, the trial has now concluded enrollment. Anixa plans to begin a Phase 2 efficacy study late next year, expected to run for two to three years.

Encouraging early findings from clinical testing

In early phase clinical trials (Phase I/II), researchers have reported that the TNBC vaccine:

Although full results and peer-reviewed publications are still pending from ongoing studies, oncologists describe the early immunologic responses as “promising”, warranting larger, controlled trials.

Why This Vaccine Matters

TNBC accounts for 10–15% of breast cancers but is responsible for a disproportionate number of breast cancer deaths.

It is twice as common in Black women and makes up 70–80% of tumours in patients with BRCA1 mutations, according to the American Cancer Society. Since TNBC lacks hormone receptors and HER2 expression, it does not respond to many targeted treatments, leaving a significant need for new approaches.

Expert context: What the science says

The broader scientific literature supports the promise of vaccines and immunotherapies in TNBC:

These trends reflect a shift in the TNBC treatment paradigm, from exclusively cytotoxic approaches to immunologically guided strategies.

What this means for patients

For patients and families grappling with TNBC, a vaccine and even one that works alongside other treatments, could:

Experts caution that early promise does not guarantee approval hence, further trials are needed to confirm long-term benefits. However, the current trajectory is one of cautious optimism.

Looking ahead: The future of TNBC management

With larger Phase II and Phase III trials now in planning or early execution, scientists hope to answer definitive questions about clinical benefit and long-term survival advantage.

If successful, a TNBC vaccine could join other advanced therapies like immunotherapies, targeted cytotoxics and CAR-T cell platforms in a multipronged arsenal against breast cancer.Anixa Biosciences holds the exclusive worldwide license for the vaccine technology, and Cleveland Clinic is entitled to royalty and commercialisation revenue. With Phase 1 complete, researchers are preparing to move the candidate into larger trials that will assess its ability to prevent cancer—not just activate immunity.The progress marks an important milestone in the long-term effort to develop the first vaccine designed to stop triple-negative breast cancer before it starts.Note: The information provided in this article is for educational purposes only and is not intended as medical advice. Always consult with a qualified healthcare professional before starting any new medication or treatment and before changing your diet or supplement regimen.