ERBB2 and breast cancer: Additionally, in HER‐2‐positive BC, the antibody‐conjugated agents TDM1 (trastuzumab conjugated to the cytotoxic agent DM1) and T‐Dxd (trastuzumab deruxtecan) have shown significant antitumor activity and are used as standard therapy in early and advanced disease, respectively.7, 8, 9, 10