Two such ADCs, ado-trastuzumab emtansine (T-DM1) and trastuzumab deruxtecan (T-DXd, also called DS8201a), were approved by the U.S. Food and Drug Administration (FDA) to treat HER2+ metastatic BC and unresectable or metastatic HER2-low BC. Here, ERBB2 is linked to breast cancer.