Dr. Bardia on the Need for Oral SERDs in ESR1-Mutant ER+ Breast Cancer

Aditya Bardia, MD, MPH, assistant professor of medicine, Harvard Medical School, attending physician, Medical Oncology, Massachusetts General Hospital, discusses the need for oral selective estrogen receptor degraders (SERDs) in ESR1-mutant, estrogen receptor (ER)–positive breast cancer.

Endocrine therapy is a mainstay of treatment in localized and metastatic ER-positive breast cancer, and the only SERD currently approved by the FDA is fulvestrant (Faslodex), which is administered as an intramuscular shot, Bardia explains. Additional therapies are needed, and there are several oral SERDs in development, Bardia adds. The need is more pressing in the metastatic setting since a subset of patients with ER-positive breast cancer can develop ESR1 mutations, and ESR1-mutated tumors are resistant to aromatase inhibitors, Bardia says. 

Since SERDs, including fulvestrant, bind to the ER, they can be effective in treating patients with ESR1 mutations, Bardia notes. Oral SERDs will continue to address this need and give patients an easier method of receiving treatment, Bardia continues. Under the right context, oral SERDs can also be used to treat patients with ESR1 wild-type disease, Bardia concludes.