ERBB2 and breast cancer: Neratinib is another irreversible pan-HER inhibitor, recently approved in breast cancer after the phase 3 ExteNET trial demonstrated that 1 year of extended neratinib therapy after adjuvant chemotherapy and trastuzumab for HER2-positive breast cancer improved 5-year invasive disease-free survival (90.2% vs 87.7%, HR, 0.73; P = 0.0083) [54].