Sacituzumab govitecan is a Trop-2-directed antibody and topoisomerase inhibitor drug conjugate used for the treatment of metastatic triple-negative breast cancer and metastatic urothelial cancer. Triple-negative breast cancer is a type of breast cancer that tests negative for estrogen receptors, progesterone receptors and human epidermal growth factor receptor 2 (HER2) protein. Therefore, triple-negative breast cancer does not respond to hormonal therapy medicines or medicines that target HER2.Sacituzumab govitecan is a conjugate of the humanized anti-Trop-2 monoclonal antibody linked with SN-38, the active metabolite of irinotecan. Each antibody having on average 7.6 molecules of SN-38 attached. SN-38 is too toxic to administer directly to patients, but linkage to an antibody allows the drug to specifically target cells containing Trop-2.