Mayo Clinic sees hope in breast cancer vaccine

(KTVU) - Treating breast cancer has long involved addressing two problems: eliminating cancer cells from the tumor and preventing the disease from returning.

Experts say the key may be to stimulate and strengthen the body's immune system to do both jobs.

Researchers at the Mayo Clinic in Florida announced they are working on a new anti-cancer vaccine to help the body resist the return of "triple-negative breast cancer," an aggressive form of breast cancer that is more likely to spread beyond the breast and more likely to come back after treatment.

The vaccine is intended to be used in combination with Trastuzumab, an immune-stimulating drug given to women after they have surgery to remove the cancer tumor.

Doctors say the combination approach activates and stimulates two types of immune cells: B-cells and T-cells.

"The vaccine provides a prevention strategy to deter cancer reformation," said Dr. Keith Knutson, a Mayo Clinic immunologist working on the study. "The body's T-cells and B-cells synergize with each other for a strong, durable, immune response."

Mayo Clinic researchers recently received a grant of $11 million from the Department of Defense to push the next studies of the vaccine ahead.

So far, doctors say early results show the vaccine promotes a "measurable immune response" with few negative side effects

Future research, to be conducted at Mayo Clinic and in collaboration with other medical centers, will help determine how long immunity lasts and whether booster shots are necessary to help the immune system continue identifying the cancerous cells. The study will also help identify specific tumor "subtypes" that will respond best to vaccine treatments.

"The standard approaches to treating cancer address the existing disease," Knutson said. "Our goal is to develop a strategy to address recurrence. We have good drugs, like Trastuzumab, that can interfere with the recurrence of (this type of) breast cancer. Our hope is that a vaccine that engages multiple aspects of the body's own immune system will build on those successes."

Mayo Clinic has several other breast cancer vaccines in clinical trial, along with over 300 clinical trials for other types of cancer.