Effect of Epirubicin Plus Paclitaxel vs Epirubicin and Cyclophosphamide Followed by Paclitaxel on Disease-Free Survival Among Patients With Operable ERBB2-Negative and Lymph Node–Positive Breast Cancer: A Randomized Clinical Trial

IMPORTANCE: Adjuvant therapy is an important and effective treatment for breast cancer. However, there is a lack of head-to-head clinical trials comparing the regimens epirubicin plus paclitaxel (EP) vs epirubicin and cyclophosphamide followed by paclitaxel (EC-P) in breast cancer. OBJECTIVE: To evaluate the noninferiority of a cyclophosphamide-free (EP) regimen compared with the standard EC-P regimen for patients with operable hormone receptor–positive, ERBB2 (formerly HER2)-negative, lymph node–positive breast cancer. DESIGN, SETTING, AND PARTICIPANTS: This prospective, open-label, phase 3, noninferiority randomized clinical trial was conducted from June 1, 2010, to June 30, 2016, in the Cancer Hospital, Chinese Academy of Medical Sciences, Beijing. Patients with hormone receptor–positive, ERBB2-negative, lymph node–positive operable breast cancer were included and randomized into 2 treatment groups. Data were analyzed from June 30, 2016, to November 1, 2022. INTERVENTIONS: Patients received adjuvant epirubicin (75 mg/m(2)) and paclitaxel (175 mg/m(2)) every 3 weeks for 6 cycles (EP regimen) or epirubicin (90 mg/m(2)) and cyclophosphamide (600 mg/m(2)) every 3 weeks for 4 cycles followed by paclitaxel (175 mg/m(2)) every 3 weeks for 4 cycles (EC-P regimen) as the intention-to-treat (ITT) population. MAIN OUTCOMES AND MEASURES: The primary outcome was disease-free survival (DFS), and the secondary outcomes included overall survival (OS), distant DFS, and safety. RESULTS: A total of 900 patients were registered, and 813 eligible patients (median age, 48 [IQR, 41-56] years) were randomly assigned to the EP group (n = 407) or the EC-P group (n = 406) after the surgical procedure. Through a median follow-up of 93.6 (IQR, 60.9-114.1) months, the hazard ratio (HR) of DFS for EP vs EC-P was 0.82 (95% CI, 0.62-1.10; 5-year DFS, 86.0% vs 80.6%; noninferior P = .001). The 5-year OS for the ITT population treated with the EP or the EC-P regimen was 94.7% vs 95.0%, respectively (HR, 0.95 [95% CI, 0.61-1.49]). Patients in the EP group had more frequent toxic effect events than those in the EC-P group. CONCLUSIONS AND RELEVANCE: In this prospective, open-label, phase 3, randomized clinical trial, the EP regimen was noninferior to the EC-P regimen. These findings supported that the EP regimen could be an effective adjuvant chemotherapy regimen for women with ERBB2-negative breast cancer. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01134523