Trastuzumab emtansine in breast cancer

Introduction: Trastuzumab emtansine (T-DM1) is a human epidermal growth factor receptor 2 (HER2)–targeted antibody–drug conjugate (ADC) composed of trastuzumab, a stable linker (MCC), and the cytotoxic agent DM1 (derivative of maytansine). Administration of T-DM1 leads to limited systemic exposure of free DM1, with no evidence of DM1 accumulation after repeated dosing.