Sacituzumab govitecan (IMMU-132) in patients with previously treated metastatic urothelial cancer (mUC): Results from a phase I/II study.

354Background: Patients (pts) with mUC who progress after platinum (PLT)-based chemotherapy and immune checkpoint inhibitor (CPI) therapy have poor outcomes and limited treatment options. Sacituzumab govitecan (SG) is a novel antibody-drug conjugate. It consists of a monoclonal antibody targeting Trop-2, an epithelial cell surface antigen overexpressed in UC, conjugated to the active metabolite of irinotecan (SN38). Methods: We performed a phase I/II basket study in pts with advanced solid tumors receiving intravenous SG administered on day 1 and 8 of 21-day cycles, until progression or unacceptable toxicity. CT/MRI scans were obtained at 8-week intervals for response assessment. We evaluated pts with mUC who progressed after ≥1 prior systemic therapy and were treated with SG at the 10 mg/kg dose level. Endpoints included safety, objective response rate (ORR) by RECIST 1.1, clinical benefit rate (CBR; complete response [CR], partial response [PR], or else SD ≥6-mo), and Kaplan-Meier estimated duration of ...