An antibody-drug conjugate (ADC) composed of a humanized immunoglobulin G1 kappa (IgG1k) monoclonal antibody directed against the tumor-associated antigen (TAA) trophoblast cell surface protein 2 (trophoblast antigen 2; calcium signal transducer 2; TROP2; TROP-2; TACSTD2; GA733-1; M1S1) conjugated, via a methyl sulfonyl pyrimidine linker, to the belotecan derivative and topoisomerase I inhibitor tirumotecan, with potential antineoplastic activity. Upon administration of sacituzumab tirumotecan, sacituzumab targets and binds to TROP2 expressed on tumor cells. Upon both extracellular pH-sensitive cleavage and intracellular enzymatic cleavage of the linker, tirumotecan is released and inhibits DNA topoisomerase I activity, thereby inhibiting DNA replication and resulting in cell cycle arrest and apoptosis in tumor cells expressing TROP2. In addition, the bystander effect induced by sacituzumab tirumotecan further inhibits tumor cell proliferation. TROP2 is a transmembrane protein overexpressed in various tumors while its expression is low and/or restricted in normal, healthy tissues; its expression is associated with enhanced tumor aggressiveness, metastasis, drug resistance and increased tumor cell survival.