Survival with Trastuzumab Emtansine in Residual HER2-Positive Breast Cancer

Patients with human epidermal growth factor receptor 2 (HER2)-positive early breast cancer with residual invasive disease after neoadjuvant systemic therapy have a high risk of recurrence and death. The primary analysis of KATHERINE, a phase 3, open-label trial, showed that the risk of invasive breast cancer or death was 50% lower with adjuvant trastuzumab emtansine (T-DM1) than with trastuzumab alone.

We randomly assigned patients with HER2-positive early breast cancer with residual invasive disease in the breast or axilla after neoadjuvant systemic treatment with taxane-based chemotherapy and trastuzumab to receive T-DM1 or trastuzumab for 14 cycles. Here, we report the prespecified final analysis of invasive disease-free survival and the second interim analysis of overall survival.