A study presented at this month’s American Association for Cancer Research annual meeting by Jose Baselga, M.D., Ph.D., suggests that tumor levels of HER2 may determine the patient’s response to treatment with T-DM1. Patients with tumors expressing higher levels of HER2 gained greater benefits from T-DM1 compared to patients with tumors expressing lower levels of HER2. Overall survival was 34.1 months for patients with increased HER2 expression versus 26.5 months for those expressing lower levels. The recently FDA-approved drug, T-DM1, combines the drug Herceptin, a man-made antibody, with a chemotherapy drug, Emtansine-attacking breast cancer in a whole new way.