Trastuzumab after adjuvant chemotherapy in HER2-positive breast cancer.

Abstract (PubMed)

BACKGROUND: Trastuzumab (Herceptin) is a monoclonal antibody that targets the HER2 protein; it is active against HER2-positive metastatic breast cancer. We assessed the efficacy and safety of trastuzumab as adjuvant therapy for early HER2-positive breast cancer. METHODS: We conducted a multinational phase 3 trial (Herceptin Adjuvant [HERA] trial) in which 5081 women with HER2-positive early breast cancer that had been treated with adjuvant chemotherapy were randomly assigned to 2 years of trastuzumab, 1 year of trastuzumab, or observation. The interim results for the 1-year-versus-observation comparison are reported here. RESULTS: After a median follow-up of 1 year, the unadjusted hazard ratio for the first event in the 1-year trastuzumab group, as compared with the observation group, was 0.54 (95% confidence interval, 0.43 to 0.67; P<0.0001), indicating a 46% reduction in the risk of recurrence with trastuzumab therapy. The absolute benefit was 8.4 percentage points (disease-free survival at 2 years: 85.8% in the trastuzumab group vs. 77.4% in the observation group). Severe cardiotoxicity developed in 0.5% of the women treated with trastuzumab. CONCLUSIONS: One year of treatment with trastuzumab after adjuvant chemotherapy significantly improves disease-free survival among women with HER2-positive early breast cancer.