Comparative Efficacy and Safety of Adjuvant Letrozole Versus Anastrozole in Postmenopausal Patients With Hormone Receptor-Positive, Node-Positive Early Breast Cancer: Final Results of the Randomized Phase III Femara Versus Anastrozole Clinical Evaluation (FACE) Trial.

Purpose The Letrozole (Femara) Versus Anastrozole Clinical Evaluation (FACE) study compared the efficacy and safety of adjuvant letrozole versus anastrozole in postmenopausal patients with hormone receptor (HR) -positive and node-positive early breast cancer (eBC). Methods Postmenopausal women with HR-positive and node-positive eBC were randomly assigned to receive adjuvant therapy with either letrozole (2.5 mg) or anastrozole (1 mg) once per day for 5 years or until recurrence of disease. Patients were stratified on the basis of the number of lymph nodes and human epidermal growth factor receptor 2 status. The primary end point was 5-year disease-free survival (DFS), and the key secondary end points were overall survival and safety. Results A total of 4,136 patients were randomly assigned to receive either letrozole (n = 2,061) or anastrozole (n = 2,075). The final analysis was done at 709 DFS events (letrozole, 341 [16.5%]; anastrozole, 368 [17.7%]). The 5-year estimated DFS rate was 84.9% for letrozole versus 82.9% for anastrozole arm (hazard ratio, 0.93; 95% CI, 0.80 to 1.07; P = .3150). Exploratory analysis showed similar DFS with letrozole and anastrozole in all evaluated subgroups. The 5-year estimated overall survival rate was 89.9% for letrozole versus 89.2% for anastrozole arm (hazard ratio, 0.98; 95% CI, 0.82 to 1.17; P = .7916). Most common grade 3 to 4 adverse events (> 5% of patients) reported for letrozole versus anastrozole were arthralgia (3.9% v 3.3%, and 48.2% v 47.9% for all adverse events), hypertension (1.2% v 1.0%), hot flushes (0.8% v 0.4%), myalgia (0.8% v 0.7%), dyspnea (0.8% v 0.5%), and depression (0.8% v 0.6%). Conclusion Letrozole did not demonstrate significantly superior efficacy or safety compared with anastrozole in postmenopausal patients with HR-positive, node-positive eBC.