Fulvestrant Versus Anastrozole in Endocrine Therapy-Naïve Women With Hormone Receptor-Positive Advanced Breast Cancer: Final Overall Survival in the Phase III FALCON Trial.

Abstract

The randomized phase III FALCON trial demonstrated significant improvement in progression-free survival (PFS) with fulvestrant versus anastrozole in postmenopausal women with endocrine therapy-naïve, hormone receptor-positive/human epidermal growth factor receptor 2-negative advanced breast cancer. Herein, the prespecified final overall survival (OS) analysis is reported. After the primary PFS analysis, data were collected on survival, serious adverse events, and health-related quality of life. The final OS analysis was triggered at ≥65% maturity and ≥8 years since the last patient was enrolled. Analyses were descriptive with nominal P values (one-sided α threshold .01845). At the data cutoff (July 11, 2022), 314 (68.0%) of 462 patients had died (fulvestrant, 157/230 [68.3%], anastrozole, 157/232 [67.7%]). The final OS analysis of FALCON demonstrated no significant difference between fulvestrant and anastrozole (medians, 44.8 and 42.7 months, respectively; hazard ratio [HR], 0.97 [95% CI, 0.77 to 1.21]; P = .7579). Among patients with nonvisceral disease (n = 208), a trend showed a 15% reduction in the relative risk of death with fulvestrant versus anastrozole (median OS, 65.2 v 47.8 months; HR, 0.85 [95% CI, 0.60 to 1.20]). Data from FALCON are consistent with published evidence of long-term clinical benefit with fulvestrant and other endocrine therapies in the subset of patients with nonvisceral disease.