T-DM1 Prolongs Survival in Advanced HER2-Positive Breast Cancer

We can expect that the next breast cancer drug soon to be approved by the FDA will be trastuzumab emtansine (T-DM1), an antibody-drug conjugate combining trastuzumab with a derivative of the cytotoxic maytansine via a stable linker molecule (JW Oncol Hematol Oct 2 2012). T-DM1 is more than just another new agent. It represents vindication for those who have worked on fusion molecules for the last 2 decades. Previous efforts with such molecules were often derailed because the linker was either unstable (resulting in systemic exposure to the toxin) or cytotoxic (resulting in prohibitive adverse effects). With T-DM1, intracellular drug delivery only to human epidermal growth factor receptor 2 (HER2)–overexpressing tumor cells has been observed…