Trastuzumab deruxtecan (DS-8201a) is an anti-human epidermal growth factor receptor 2 (HER2) antibody-drug conjugate (ADC). Trastuzumab deruxtecan is composed of a humanized anti-HER2 antibody, an enzymatically cleavable peptide-linker, a topoisomerase I inhibitor (a toxin component of Dxd). Trastuzumab deruxtecan can be used for the research of HER2-positive breast cancer and gastric cancer.