BOLERO-2 trial participants were postmenopausal women with estrogen receptor–positive breast cancer who relapsed or progressed on a nonsteroidal aromatase inhibitor. They were randomized to receive a 10-mg oral daily dose of everolimus plus 25 mg of exemestane once daily, or placebo and 25 mg of exemestane daily; treatment with everolimus conferred a median 4.2-month progression-free survival advantage, more than doubling the median progression-free survival from 3.2 months in the placebo group to 7.8 months in the treatment group. Based on these findings, the U.S. Food and Drug Administration approved the drug for this indication in July, making it the first mTOR inhibitor approved for advanced hormone receptor–positive breast cancer.
BOLERO-2 was sponsored by Novartis Pharmaceuticals. Dr. Rugo reported receiving research funding from Merck, Novartis, and Pfizer. Dr. Hart and Dr. Perez reported having no relevant financial disclosures.