FALCON: A phase III randomised trial of fulvestrant 500 mg vs. anastrozole for hormone receptor-positive advanced breast cancer

Background: This Phase III, randomised, double-blind, multicentre trial (FALCON; NCT01602380) compared the selective estrogen receptor (ER) degrader (SERD) fulvestrant with anastrozole in patients with ER- and/or progesterone receptor-positive locally advanced or metastatic breast cancer who had not received prior hormonal therapy. Methods: Patients were randomised 1:1 to fulvestrant (500 mg IM on Days 0, 14, 28, then each 28 days) or anastrozole (1 mg daily). The primary endpoint was progression-free survival (PFS), assessed via RECIST 1.1, surgery/radiotherapy for disease worsening, or death. Secondary endpoints were: overall survival (OS); objective response rate (ORR, complete response [CR] or partial response [PR]); duration of response (DoR); expected DoR (EDoR); clinical benefit rate (CBR; CR, PR, or stable disease ≥24 weeks); duration of clinical benefit (DoCB); expected DoCB (EDoCB); health-related quality of life (HRQoL); and safety