92O Everolimus (EVE)+ letrozole (LET) in Asian patients with estrogen receptor–positive (ER+), human epidermal growth factor receptor 2–negative (HER2−) advanced breast cancer …

Background: Results from the primary analysis of the open-label, single-arm, phase 2 study BOLERO-4 demonstrated that first-line (1L) EVE+ LET was an effective combination with a manageable safety profile in postmenopausal patients with ER+ HER2− ABC. Here, we present results from a predefined subgroup analysis of 1L progression-free survival (PFS) and safety by race (Asian versus non-Asian).Methods: Patients received EVE 10 mg/day+ LET 2.5 mg/day until disease progression, unacceptable toxicity, or withdrawal of consent. 1L PFS per local investigator assessment was analyzed overall on the full analysis set (FAS; primary endpoint) and by patient subgroup. This study was not designed to use the SWISH protocol for prevention for stomatitis.Results: At the data cutoff (December 17, 2016), 44 Asian and 158 non-Asian (Caucasian 72%;...