In the post-neoadjuvant setting, the randomized, multicenter phase III trial DESTINY-Breast05 (NCT04622319) is evaluating T-DXd vs T-DM1 as a post-neoadjuvant treatment for patients with HER2-positive breast cancer with residual invasive disease post-neoadjuvant therapy. This evidence concerns the gene ERBB2 and breast carcinoma.