Dr. Mortimer on Brain Metastases in HER2+ Breast Cancer

Joanne Mortimer, MD, associate director for Education and Training, Comprehensive Cancer Center, Baum Family Professor in Women’s Cancers, vice chair and professor, Department of Medical Oncology and Therapeutics Research, director, Women’s Cancer Programs, and breast cancer oncologist, City of Hope, discusses brain metastases in women with HER2-positive breast cancer.

One of the continual challenges in HER2-positive breast cancer is disease that has metastasized to the brain, says Mortimer. Moreover, brain metastases seem to be more common in HER2-positive breast cancer than in some of the other subtypes.

As the lifespan of women with HER2-positive breast cancer increases, so does the chance of disease metastasizing to the brain. Currently, radiation and surgery are the staples of treatment for these women. However, new brain metastases may develop in the setting of prior radiation or in places that are inaccessible to radiation and surgery, explains Mortimer. For those women, there are some data to suggest that lapatinib (Tykerb) and neratinib (Nerlynx) have some activity. Additionally, ado-trastuzumab emtansine (T-DM1; Kadcyla) has been shown to cause regression of brain metastases in very small series, she adds.

One of the most promising agents under investigation is tucatinib (ONT-380). In the ongoing phase II HER2CLIMB trial, patients are randomized to receive tucatinib with capecitabine and trastuzumab (Herceptin) or capecitabine and trastuzumab alone. Tucatinib is unique in that it is a selective HER2 drug that has been shown to have some activity in preventing and targeting brain metastases, concludes Mortimer.