A randomized, double-blind, double-dummy, multicenter study (FALCON, NCT01602380) was conducted in postmenopausal patients with locally advanced or metastatic breast cancer who were ER-positive and/or PgR-positive and HER2-negative to compare the clinical efficacy and safety of 500 mg of Fulvestrant (Faslodex, Fulvestrant) and 1 mg of anastrozol (Arimidex, anastrozol).
Comparison of clinical efficacy of Fulvestrant and anastrozol
Trial content
A total of 462 patients were randomized 1:1 to receive 500mg of Fulvestrant injection intramuscularly on days 1, 15, 29, and every 28 (+\/-3) days thereafter, or 1mg of anastrozol orally daily. This study compared the efficacy and safety of 500mg of Fulvestrant injection and 1mg of anastrozol. Randomization was stratified by disease background (locally advanced or metastatic), use of previous chemotherapy for advanced disease, and the presence of measurable disease.
Trial Indicators
The primary efficacy endpoint of this study was progression-free survival (PFS) assessed by the investigator according to RECIST v.1.1 (Response Evaluation Criteria in Solid Tumors). Secondary efficacy endpoints included overall survival (OS), objective response rate (ORR), and duration of response (DoR).
Baseline Examination
The median age of patients participating in this study was 63 years (range, 36 to 90 years). Most patients (87%) had metastatic disease at baseline. At baseline, 55% of patients had visceral metastases. 17% of patients had received one prior chemotherapy regimen; 84% of patients had measurable disease. The metastatic sites were as follows: musculoskeletal 59%, lymph nodes 50%, respiratory system 40%, liver (including gallbladder) 18%.
Trial Results
Progression-free Survival
The median progression-free survival (mPFS) of the Fulvestrant group was 16.6 months, 3.1 months higher than that of anastrozole (mPFS was 13.8 months).
Overall survival (OS)
The overall survival rate of the Fulvestrant group was 67%, and the overall survival rate of anastrozole was 75%. The median overall survival was not reached (NR).
Objective efficacy (DOR)
The objective efficacy of the Fulvestrant group was 49.1%, which was not much different from anastrozole (44.9%); and in terms of median DOR, the DOR of Fulvestrant was 20 months, and the DOR of anastrozole was 13.2 months, and the DOR of Fulvestrant was 6.8 months higher than that of anastrozole.
Summary
Compared with anastrozole, Fulvestrant has significantly improved progression-free survival and objective efficacy, which improves the patient's survival and life treatment.
