Long-term (8 years) assessment of trastuzumab-related cardiac events in the HERA trial.

525 Background: Trastuzumab-related cardiac dysfunction may occur in patients (pts) treated with adjuvant therapy and it is mostly reversible. We report the long-term outcome of pts with cardiac dysfunction treated with adjuvant trastuzumab (T) in the Herceptin Adjuvant (HERA) trial. Methods: HERA is a three-arm, randomized trial that compared 1 year or 2 years of T with observation (Obs) in women with HER2-positive early breast cancer (EBC). Eligible pts had a left ventricular ejection fraction (LVEF) ≥ 55% at study entry (i.e. after completion of (neo)adjuvant chemotherapy with or without radiotherapy). Cardiac function was closely monitored throughout the trial. This analysis at 8-year median follow-up considers pts randomly assigned to 1 year or 2 years of T therapy or observation. Results: 5102 pts were randomized to HERA. The “as treated” safety population is considered: 2 years T (N=1,673), 1 year T (N=1,682) and Obs (N=1,744). Cardiac events leading to T discontinuation in the 1-year and 2-year ar...