Using sacituzumab govitecan for metastatic urothelial carcinoma after prior treatment with enfortumab vedotin: A single institution experience.

Abstract

78 Background: The Trop-2-directed antibody drug conjugate sacituzumab govitecan (SG) has demonstrated efficacy in metastatic urothelial cancer (mUC) previously treated with checkpoint inhibitors +/- prior chemotherapy based on the results from the TROPHY U-01 study. However, only 10/118 and 7/38 patients in the reported Cohorts 1 and 2 respectively had received prior enfortumab vedotin (EV). Given that EV is preferred prior to SG given proven overall survival (OS) benefit vs chemotherapy, we analyzed our institution’s experience to determine real-world outcomes when SG is used after prior EV treatment. Methods: We identified patients who had received EV for mUC at our institution and identified a subset of patients who had received SG after prior treatment with EV. Patient characteristics (e.g. age, sex, primary site of disease) were noted, as well as the number of lines of prior systemic therapy for mUC. Best response to SG was recorded, as well as time to progression, reason for discontinuation, and time to death. Progression free survival (PFS) was calculated from time of SG treatment initiation until progression or death, and overall survival (OS) was calculated from time of SG treatment initiation until death. Results: Ten patients were identified having been treated with SG for mUC after prior EV treatment. Seven out of ten were male and the median age at time of initial EV treatment was 68 years. Half of the patients had the primary upper tract urothelial carcinoma. There were no responses to treatment with SG; the best response to SG treatment was stable disease (SD) in 3/10 patients, progressive disease in 4/10 patients, and three patients’ responses were not assessed due to death or transition to hospice at time of last follow-up. The median PFS was 2.5 months and median OS was 3.2 months. Only two patients survived more than six months (7.1 months and 10.8 months). Conclusions: In this small retrospective series at a single institution, real-world outcomes (response to treatment, PFS, OS) using SG for mUC after prior EV treatment appear to be worse than the reported outcomes in TROPHY-U01 trial. The lack of prior EV treatment in the majority of the SG clinical trial patients could contribute to these disparate results.