ERBB2 and breast carcinoma: In line with these findings, Modi et al. observed in 112 HER2-positive breast cancer patients that were previously treated with trastuzumab emtansine and then treated with the recommended dose of trastuzumab deruxtecan 61% of responding patients with a median response duration of 14.8 months and median duration of progression-free survival of 16.4 months [501].