Dr. Cristofanilli on Lasofoxifene in ESR1-Mutant Breast Cancer

Massimo Cristofanilli, MD, professor of medicine, Hematology Oncology Division, Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, discusses the use of lasofoxifene in patients with ESR1-mutant breast cancer.

In May 2019, the FDA granted a fast track designation to lasofoxifene for the treatment of female patients with estrogen receptor(ER)—positive, HER2-negative metastatic breast cancer who harbor ESR1 mutations. Lasofoxifene is a nonsteroidal selective ER modulator that has shown activity against mutations of the ER.

If the agent receives regulatory approval, it will lead to widespread use in the clinic, says Cristofanilli. ESR1 mutations are common in patients with metastatic breast cancer who progress on prior endocrine therapy. Given their frequency, it is important to educate the field on the importance of ER mutations. Currently, this represents an area of high unmet need. If the agent moves forward, it is also likely to be evaluated in combination with CDK4/6 inhibitors, concludes Cristofanilli.