Jacksonville, Florida - Researchers on Mayo Clinic’s Florida campus have been awarded a $13.3 million, five-year federal grant to test a vaccine designed to prevent the recurrence of triple-negative breast cancer, a subset of breast cancer for which there are no targeted therapies.

The clinical trial, which will enroll 280 patients at multiple clinical sites, is expected to begin early in 2016.

The grant, the Breakthrough Award from the U.S. Department of Defense’s Breast Cancer Research Program, will fund a national, phase II clinical trial testing the ability of a folate receptor alpha vaccine to prevent recurrence of this aggressive cancer following initial treatment.

A 22-patient phase I clinical trial, previously conducted by the grant’s principal investigator, Keith Knutson, Ph.D., in the Department of Immunology at Mayo Clinic’s Florida campus, found the vaccine was safe. It did not induce autoimmunity — a failure of the body’s immune system to recognize its own cells and tissues as “self” — as some vaccines can.

The vaccine was designed by Dr. Knutson and initially tested by researchers at Mayo Clinic’s Rochester, Minnesota, campus for safety and its ability to stimulate the immune system.

It exploits the need of triple-negative breast cancer to take in folic acid, an essential vitamin, to grow, says Dr. Knutson. Because of that need, these tumors overproduce the folate receptor alpha, which latches on to folic acid in the tumor’s microenvironment.

Evidence shows some patients naturally produce an immune response to parts of these receptors, “but the cancer is much too strong for what is typically a weak immune response,” says Dr. Knutson.

The vaccine is designed to boost the immune system to rapidly react to presence of the receptor on cancer cells early in the course of tumor recurrence.

“We believe this vaccine will provide a much more robust and sustained immune response to these receptors, which will then improve the body’s ability to directly or indirectly kill the tumor by cutting off access to the folate it needs to respond to cancer if it begins to re-emerge in these patients,” he says.

The grant is a collaborative effort among Mayo Clinic’s clinicians, clinical researchers and basic science researchers, says Edith Perez, M.D., a breast cancer researcher at the Mayo Clinic Cancer Center in Florida. Dr. Perez is a partner and principal investigator on the grant with Dr. Knutson.

“Continued improvements in therapies for patients with triple-negative breast cancer are one of our most important research goals,” Dr. Perez says. “We owe it to our patients to develop studies such as the ones that will now be possible because of this grant.”

Mayo Clinic and Dr. Knutson have a financial interest in the technology referenced in this news release. TapImmune Inc. has a license for the vaccine and will supply it for the trial.