Trastuzumab emtansine (T-DM1) versus trastuzumab in Chinese patients with residual invasive disease after neoadjuvant chemotherapy and HER2-targeted therapy for HER2-positive breast cancer in the phase 3 KATHERINE study

In the KATHERINE study (NCT01772472), patients with HER2-positive early breast cancer (EBC) and residual invasive disease after neoadjuvant chemotherapy plus HER2-targeted therapy who were treated with adjuvant trastuzumab emtansine (T-DM1) had a 50% reduction in the risk of an invasive disease-free survival (IDFS) event compared to patients treated with adjuvant trastuzumab. In metastatic disease, T-DM1 has resulted in higher rates of thrombocytopenia in Asian versus non-Asian patients. Here, we report safety and efficacy in Chinese patients from KATHERINE.