ERBB2 and breast cancer: The ExteNET study demonstrated that 1 year of neratinib, given after standard trastuzumab-based adjuvant therapy, significantly improved iDFS in women with early-stage HER2-positive BC, with a 27% relative reduction in the risk of an iDFS event (stratified HR 0.73, 95% CI 0.57–0.92; P = 0.