Francisco Esteva, MD, PhD, director, breast medical oncology program, NYU Langone’s Perlmutter Cancer Center, highlights endocrine therapy plus CDK4/6 inhibitors for estrogen receptor (ER)-positive, HER2-negative metastatic breast cancer. Findings from the MONALEESA-3 trial were presented at the 2018 ASCO Annual Meeting.

MONALEESA-3, a study conducted in nearly 730 patients, was called unique by Esteva because eligible patients were treated in the frontline setting without any prior hormone therapy or chemotherapy. The trial tested the clinical efficacy of ribociclib (Kisqali) and fulvestrant (Faslodex) compared with fulvestrant alone in the first- or second-line setting of patients with hormone receptor-positive, HER2-negative advanced breast cancer.

Patients received 600 mg/day of ribociclib on a 3-week on, 1-week off schedule. All patients also received fulvestrant 500 mg/day. Esteva says that this was the first study showing a significant increase in overall survival with a CDK4/6 inhibitor paired with fulvestrant in the frontline setting.

Esteva also shed light on encouraging phase II data with sacituzumab govitecan in ER-positive breast cancer, immunotherapy, and the phase III TAILORx trial, which focused on less chemotherapy in the adjuvant setting for select patients with breast cancer.

He adds that because of further research, chemotherapy should only be given to patients with high-risk breast cancer, while patients with low or intermediate risk should be treated with endocrine therapy alone.