Three-Year Follow-up of Neoadjuvant Chemotherapy With or Without Anthracyclines in the Presence of Dual ERBB2 Blockade in Patients With ERBB2-Positive Breast Cancer: A Secondary Analysis of the TRAIN-2 Randomized, Phase 3 Trial.

IMPORTANCE: Primary analysis of the TRAIN-2 study showed high pathologic complete response rates after neoadjuvant chemotherapy with or without anthracyclines plus dual ERBB2 (formerly HER2) blockade. OBJECTIVE: To evaluate 3-year event-free survival (EFS) and overall survival (OS) of an anthracycline-free and anthracycline-containing regimen with dual ERBB2 blockade in patients with stage II and III ERBB2-positive breast cancer. DESIGN, SETTING, AND PARTICIPANTS: A total of 438 patients with stage II and III ERBB2-positive breast cancer were enrolled in this randomized, clinical, open-label phase 3 trial across 37 hospitals in the Netherlands from December 9, 2013, until January 14, 2016. Follow-up analyses were performed after a median follow-up of 48.8 months (interquartile range, 44.1-55.2 months). Analysis was performed on an intention-to-treat basis. INTERVENTIONS: Participants were randomly assigned on a 1:1 basis, stratified by age, tumor stage, nodal stage, and estrogen receptor status, to receive 3 cycles of fluorouracil (500 mg/m2), epirubicin (90 mg/m2), and cyclophosphamide (500 mg/m2), followed by 6 cycles of paclitaxel and carboplatin or 9 cycles of paclitaxel (80 mg/m2 days 1 and 8) and carboplatin (area under the concentration-time curve, 6 mg/mL/min). Both groups received trastuzumab (6 mg/kg; loading dose 8 mg/kg) and pertuzumab (420 mg intravenously; loading dose 840 mg) every 3 weeks. MAIN OUTCOMES AND MEASURES: Three-year EFS, OS, and safety. RESULTS: A total of 438 women were randomized, with 219 per group (anthracycline group, median age, 49 years [interquartile range, 43-55 years]; and nonanthracycline group, median age, 48 years [interquartile range, 43-56 years]). A total of 23 EFS events (10.5%) occurred in the anthracycline group and 21 EFS events (9.6%) occurred in the nonanthracycline group (hazard ratio, 0.90; 95% CI, 0.50-1.63; favoring nonanthracyclines). Three-year EFS estimates were 92.7% (95% CI, 89.3%-96.2%) in the anthracycline group and 93.6% (95% CI, 90.4%-96.9%) in the nonanthracycline group and 3-year OS estimates were 97.7% (95% CI, 95.7%-99.7%) in the anthracycline group and 98.2% (95% CI, 96.4%-100%) in the nonanthracycline group. The results were irrespective of hormone receptor and nodal status. A decline in left ventricular ejection fraction of 10% or more from baseline to less than 50% was more common in patients who received anthracyclines than those who did not (17 of 220 [7.7%] vs 7 of 218 [3.2%]; P = .04). Two patients treated with anthracyclines developed acute leukemia. CONCLUSIONS AND RELEVANCE: This follow-up analysis of the TRAIN-2 study shows similar 3-year EFS and OS estimates with or without anthracyclines in patients with stage II and III ERBB2-positive breast cancer. Anthracycline use is associated with increased risk of febrile neutropenia, cardiotoxic effects, and secondary malignant neoplasms. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01996267.