First-of-its Kind Study Focuses on Preventive Breast Cancer Vaccine

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Thomas Budd, MD, Cleveland Clinic, Taussig Cancer Institute

Cleveland Clinic researchers have opened a novel study for a vaccine aimed at eventually preventing triple-negative breast cancer, the most aggressive and lethal form of the disease.

This Phase I trial is designed to determine the maximum tolerated dose of the vaccine in patients with early-stage triple-negative breast cancer and to characterize and optimize the body’s immune response. The U.S. Food and Drug Administration recently approved an Investigational New Drug application for the vaccine, which permits Cleveland Clinic and partner Anixa Biosciences, Inc. to start the study.

“We are hopeful that this research will lead to more advanced trials to determine the effectiveness of the vaccine against this highly aggressive type of breast cancer,” said G. Thomas Budd, MD, of Cleveland Clinic’s Taussig Cancer Institute and principal investigator of the study. “Long term, we are hoping that this can be a true preventive vaccine that would be administered to healthy women to prevent them from developing triple-negative breast cancer, the form of breast cancer for which we have the least effective treatments.”

Despite representing only about 12% to 15% of all breast cancers, triple-negative breast cancer accounts for a disproportionately higher percentage of breast cancer deaths and has a higher rate of recurrence. This form of breast cancer is twice as likely to occur in African American women, and approximately 70% to 80% of the breast tumors that occur in women with mutations in the BRCA1 genes are triple-negative breast cancer.

Vincent Tuohy, PhD, is the primary inventor of the vaccine and staff immunologist at Cleveland Clinic’s Lerner Research Institute. The investigational vaccine targets a breast-specific lactation protein which is no longer found post-lactation in normal, aging tissues but is present in the majority of triple-negative breast cancers. Activating the immune system against this “retired” protein provides pre-emptive immune protection against emerging breast tumors that express it. The vaccine also contains an adjuvant that activates an innate immune response that allows the immune system to mount a response against emerging tumors to prevent them from growing.

Preclinical research found that a single vaccination could prevent breast tumors from occurring in mouse models, while also inhibiting the growth of already existing breast tumors. 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.

Funded by the U.S. Department of Defense, the new study at Cleveland Clinic will include 18 to 24 patients who have completed treatment for early-stage triple-negative breast cancer within the past three years and are currently tumor-free but at high risk for recurrence. During the course of the study, participants will receive three vaccinations, each two weeks apart, and will be closely monitored for side effects and immune response. The study is estimated to be completed in September 2022.

Researchers anticipate that a subsequent trial will involve healthy, cancer-free women at high risk for developing breast cancer who have decided to undergo voluntary bilateral mastectomy to lower their risk.

Edited by Gary Cramer