On 20 December 2019, the FDA granted accelerated approval for the treatment of unresectable or metastatic HER2+ BC to Fam-trastuzumab deruxtecan-Nxki (T-DxD, Enhertu®), composed of trastuzumab and topoisomerase I inhibitor (DXd) [228]. This evidence concerns the gene ERBB2 and breast cancer.