December 11, 2025, CLEVELAND: Cleveland Clinic researchers are presenting final Phase 1 data from their novel study of a vaccine aimed at preventing triple-negative breast cancer , the most aggressive and lethal form of the disease.
The study team found that the investigational vaccine produced an immune response in the majority (74%) of all participants and was safe and well tolerated. They determined the maximum tolerated dose and described that side effects primarily consisted of mild skin inflammation at the injection site. The findings , which will inform the subsequent Phase 2 study, are being presented at the San Antonio Breast Cancer Symposium.
"Triple-negative breast cancer remains one of the most challenging forms of the disease to treat effectively," said G. Thomas Budd, M.D. , of Cleveland Clinic's Cancer Institute and principal investigator of the study. "The results from this trial are promising, as they suggest the investigational vaccine is not only safe and well tolerated but also capable of inducing immune responses in over 70% of participants."
Funded by the U.S. Department of Defense, the clinical trial evaluated safety and monitored immune response to the vaccine. The Phase 1 study ( NCT04674306 ), conducted at Cleveland Clinic's Main Campus in partnership with Anixa Biosciences, Inc ., included 35 patients across three cohorts:
- Phase 1a - patients who completed treatment for early-stage, triple-negative breast cancer within the past three years and are tumor-free but at high risk for recurrence.
- Phase 1b - cancer-free individuals who carry genetic mutations associated with elevated breast cancer risk, and who elected to have a preventative mastectomy.
- Phase 1c - early-stage triple-negative breast cancer patients who received pre-operative chemoimmunotherapy and surgery and were treated with pembrolizumab. These patients have residual cancer in the breast tissue, making them at risk of recurrence.
Launched in 2021, the trial enrolled 26 patients in Phase 1a, four in Phase 1b, and five in Phase 1c. Anixa is planning a Phase 2 study to evaluate the efficacy of the vaccine. The trial is expected to begin late next year and is projected to last approximately two to three years.
There is a great need for improved treatments for triple-negative breast cancer, which does not have biological characteristics that typically respond to hormonal or targeted therapies. Although it makes up only 10-15% of breast cancer cases, it causes a disproportionately high number of breast cancer deaths, according to the American Cancer Society. This aggressive cancer is twice as common in Black women, and accounts for 70-80% of breast tumors in patients with BRCA1 gene mutations.
The investigational vaccine is based on pre-clinical research led by the late Vincent Tuohy, Ph.D., who was the Mort and Iris November Distinguished Chair in Innovative Breast Cancer Research at Cleveland Clinic. Dr. Tuohy's decades of groundbreaking research led to the development of this investigational vaccine.
The vaccine targets a lactation protein, α-lactalbumin, which is no longer found after lactation ceases in normal, aging breast tissues but is present in most triple-negative breast cancers. The vaccine is designed to stimulate the immune system to attack tumors if they develop.
The study is based on Dr. Tuohy's research that showed that activating the immune system against α-lactalbumin was safe and effective in preventing breast tumors in mice. The research, originally published in Nature Medicine , was funded in part by philanthropic gifts from more than 20,000 people over the last 12 years.
"It was Dr. Tuohy's hope that this vaccine would demonstrate the potential of immunization as a new way to combat breast cancer, and that a similar approach could someday be applied to other types of malignancies," said Justin Johnson, Ph.D., researcher in Cleveland Clinic's Department of Inflammation and Immunity and presenter of the study. "Our findings that the majority of participants across all three cohorts demonstrated an immune response to α-lactalbumin is an encouraging sign for the vaccine's potential moving forward."
Anixa is the exclusive worldwide licensee of the novel breast cancer vaccine technology developed at Cleveland Clinic. Cleveland Clinic is entitled to royalties and other commercialization revenues from the company.
