ERBB2 and breast cancer: Based on the above appealing phase 2 data, a multicenter, randomized, double-blind, placebo-controlled, phase 3 trial (the ExteNET trial) was conducted, where 2840 patients with previously trastuzumab-treated stage II-III HER2-positive BC were randomly assigned (1:1) to receive neratinib (n = 1420) and placebo (n = 1420)(Chan et al. 2016; Chia et al. 2019).