Fact Check

What We Know About the Breast Cancer Vaccine

Is prevention in our future?

Published Oct 29, 2021

Pharmacy Research Technican Brenda Flenoy demonstrates a mock preperation of the new breast cancer vaccine in the pharmacy of the basement of the Taussig Cancer Center on Monday, Oct. 25, 2021. Photos by Lisa DeJong (Cleveland Clinic)
Image Via Cleveland Clinic
Researchers at Cleveland Clinic began a phase I study in October 2021 to test the safety of a vaccine aimed at preventing the most aggressive form of breast cancer.

After two decades of research, experts at the Cleveland Clinic announced the beginning of a human clinical trial to test the safety of a vaccine to potentially prevent triple-negative breast cancer, the most aggressive form of the disease.

In an Oct. 26, 2021, news release, the nonprofit medical center noted that the U.S. Food and Drug Administration had approved the investigational drug application in partnership with Anixa Biosciences, Inc., a biotech company focused on cancer and infectious diseases. Scientists at the clinic’s Lerner Research Institute launched the Phase I study, which is aimed at determining the highest dose that can be given safely without causing severe side effects, in October 2021. These tests follow laboratory tests and animal studies, and predate phase II clinical trials to determine the efficacy rates, according to the American Cancer Society.

“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 Dr. G. Thomas Budd, of the clinic’s Taussig Cancer Institute. “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.”

Triple-negative breast cancer represents between 12% and 15% of all breast cancers, but it accounts for a disproportionate number of deaths associated with the disease because it does not have specific receptors commonly found in breast cancer.

“Think of cancer cells as a house. The front door may have three kinds of locks, called receptors,” wrote the Centers for Disease Control and Prevention (CDC). These “locks” include the female hormones estrogen and progesterone as well as a protein called human epidermal growth factor (HER2).

“If your cancer has any of these three locks, doctors have a few keys (like hormone therapy or other drugs) they can use to help destroy the cancer cells. But if you have triple-negative breast cancer, it means those three locks aren’t there.”

In short, specialists have “fewer keys” they can turn to for treatment.

But the new vaccine is aimed at adding another key to the chain by preventing breast cancer before it occurs, particularly in the more aggressive forms of the disease. This is done by targeting a lactation protein, α-lactalbumin, that is only expressed when a woman is lactating. As a woman ages, this protein normally wanes but a majority of women diagnosed with triple-negative breast cancer retain the protein. The vaccine works by activating the immune system against the “retired” protein to provide “preemptive immune protection against emerging breast tumors that express α-lactalbumin. An adjuvant (a substance added to enhance the body's immune response) included in the vaccine also prompts the immune system to respond to potential emerging tumors before they grow.

The new study is based on research published in the peer-reviewed scientific journal Nature Medicine, which found α-lactalbumin protein was safe and effective in preventing breast tumors in mice, and a single dose could both prevent tumors from forming and inhibit the growth of those already existing.

The funding is set to be completed in September 2022 and will follow between 18 and 24 patients who have finished treatment for early-stage triple-negative breast cancer within the past three years. Though test subjects will be tumor-free at the time of the study, they are at a high risk for recurrence. Three vaccine doses will be given two weeks apart.

If the phase I study is successful, researchers hope to test the vaccine in cancer-free women who are at a high risk for developing breast cancer, typically those who carry mutations in either the BRCA1 or BRCA2 gene — both of which have been identified as risk factors for breast cancer.

“This vaccine strategy has the potential to be applied to other tumor types,” said vaccine inventor and immunologist Vincent Tuohy. “Our translational research program focuses on developing vaccines that prevent diseases we confront with age, like breast, ovarian and endometrial cancers. If successful, these vaccines have the potential to transform the way we control adult-onset cancers and enhance life expectancy in a manner similar to the impact that the childhood vaccination program has had.”

Madison Dapcevich is a former writer for Snopes.

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