Dr. O'Regan Discusses BELLE-3 Study in Breast Cancer

Ruth O’Regan, MD, division head of Hematology and Oncology in the Department of Medicine at the University of Wisconsin School of Medicine and Public Health, discusses BELLE-3, a phase III study of buparlisib (BKM120) plus fulvestrant (Faslodex) in postmenopausal women with hormone receptor (HR)-positive, HER2-negative, locally advanced or metastatic breast cancer, who progressed on or after mTOR inhibitor-based treatment and were treated with an aromatase inhibitor.

The BELLE-3 study evaluated PI3K inhibition in HR-positive breast cancers that were resistant to both endocrine therapy and mTOR inhibition. The trial studied 432 postmenopausal women with HR-positive/HER2-negative locally advanced or metastatic breast cancer. One group was given a combination of buparlisib plus fulvestrant while the other was given fulvestrant plus placebo.

Progression-free survival was significantly improved in those who were administered the combination buparlisib plus fulvestrant in comparison to those who were given placebo plus fulvestrant. However, there were more adverse events in the buparlisib arm, such as intense mood changes.

Although the data was inconclusive, this agent and other PI3K inhibitors should be studied alongside other types of cancers to see where it could work best, says O’Regan.