Immunotherapy Emerges as Promising Strategy in Breast Cancer

Mary L. Disis, MD

Next-generation immunotherapy in breast cancer treatment is an active field of scientific exploration with the potential to yield a vaccine in the near future, according to Mary L. Disis, MD, a leading researcher in the field.

Disis, professor in the Division of Oncology at the University of Washington School of Medicine in Seattle, described the rationale for immunotherapy approaches to breast cancer and possible advantages in such therapies during several presentations at the 29th Annual Miami Breast Cancer Conference this week. She is a co-investigator for the Cancer Immunotherapy Trials Network, an initiative the National Cancer Institute launched to spur investigation of such therapeutics.

During the past two years, the attention in immunotherapy has been focused upon prostate cancer, where sipuleucel-T (Provenge) became the first FDA-approved therapeutic cancer vaccine in 2010, and upon melanoma, where the novel immunogenic agent ipilimumab (Yervoy) was approved last year.

Disis said breast cancer “wasn’t classically thought of as an immunogenic tumor,” but that it presents favorable attributes for such approaches. “In fact, many of the favorable immune characteristics that are present in more classically immunogenic tumors, such as melanoma, are operative in breast cancer,” she said.

Disis said breast tumors exhibit type 1 inflammation, a gene signature associated with unusually high relapse; a high density of T cells penetrating the tumors, which battle cancer-causing antigens and are a predictor of survival; and modulation of the “self regulatory” response, which can be targeted.

In addition, Disis said existing therapies can be employed as immunogenic agents. She said several chemotherapy drugs are able to stimulate the immune system, and, in some cases, reverse the immune suppression inhibiting T cells.

“Stimulating a robust immune response will result in the development of immunologic memory,” she wrote in one of her conference abstracts. “T cells capable of recognizing and killing tumor cells will persist in lymph nodes for years and will be poised to attack an antigen-expressing tumor when it recurs.”

The slower-growing nature of breast tumors also can be an ally of immunotherapy, particularly strategies that involve propagating T cells. “This is a perfect time frame for the immune system to be stimulated, get a handle on the tumor, and overwhelm the tumor,” said Disis.

Disis anticipates a productive future for immunotherapeutics at every stage of breast cancer. She said there will be strategies for preventing breast cancer in high-risk women, targeting advanced disease, preventing relapse, and moving into “molecular-targeted prophylaxis using the immune system.”

“There will be a vaccine to prevent breast cancer recurrence in the next limited number of years,” she said.

<<< View the On-site Coverage From the 29th Annual Miami Breast Cancer Conference.