Deruxtecan, a topoisomerase I inhibitor, is an exatecan derivative (DX-8951 derivative) with a cleavable pepetide linker and a maleimide group. The maleimide group in Deruxtecan can react with antibody to form antibody-drug conguates (ADC) such as Trastuzumab deruxtecan (DS-8201a), which is a HER2-targeting antibody–drug conjugate. DS-8201a significantly suppressed tumor growth in an immunocompetent mouse model with human HER2-expressing CT26.WT (CT26.WThHER2) cells. DS-8201a is currently in clinical trials