Phase II Interventional Study (N0337) of Capecitabine in Combination With Vinorelbine and Trastuzumab for First- or Second-Line Treatment of HER2-Positive Metastatic Breast Cancer: A North Central Cancer Treatment Group Trial

BackgroundWe conducted a multiinstitutional phase II study of capecitabine in combination with vinorelbine and trastuzumab in patients eligible to receive first- or second-line treatment for human epidermal growth factor receptor type 2 (HER2)-positive (HER2+) metastatic breast cancer (MBC).Patients and MethodsThe study was designed to test that the true confirmed response rate (CRR) was at most 45% vs. a true CRR of at least 65%. Between March 2005 and June 2008, eligible patients received capecitabine 825 mg/m2 orally on days 1 to 14, vinorelbine 25 mg/m2 intravenously on days 1 and 8 every 3 weeks, and trastuzumab 8 mg/kg intravenously on day 1 week 1 and 6 mg/kg every 3 weeks. The main outcome measure was CRR.ResultsOf 47 women accrued, 45 were evaluable. This design required at least 25 confirmed responses in the 45 evaluable patients for the treatment to be considered promising. Thirty women (67%) achieved a confirmed response; 25 women (56%) had a confirmed partial response (PR); 5 women (11%) had confirmed complete responses (CRs). Median progression-free survival (PFS) was 11.3 months (95% confidence interval [CI], 8.4-16.7 months). Median overall survival was 28.5 months (95% CI, 24.8-36.4 months).ConclusionsThis triplet combination demonstrated promising activity in patients with HER2+ MBC.