Outcomes of metastatic urothelial carcinoma following discontinuation of enfortumab-vedotin.

Background: Enfortumab vedotin (EV) is approved to treat metastatic urothelial carcinoma (mUC) following platinum and PD1/L1 inhibitors. Since the outcomes and patterns of therapy of patients following discontinuation of EV are unknown, we conducted a retrospective study to assess this issue.

Methods: Data were retrospectively obtained from patients with mUC following discontinuation of EV after prior platinum-based chemotherapy and PD1/L1 inhibitors. Objective response rate (ORR) was evaluated in those who received therapy post-EV. Statistical analyses were performed to describe the overall survival (OS) and compare patient characteristics and outcomes of those who did or did not receive treatment post-EV.

Results: Data were available for 63 patients from 6 institutions: 46 (73%) were male and median age was 68 years (range 43-83). The median OS was 32 weeks. Thirty-two patients (51%) received therapy after EV. The OS of those who did vs. did not receive post-EV therapy was significantly different (median 43.1 vs. 16.9 weeks, P = .015). Longer duration of prior EV therapy was associated with receipt of post-EV therapy (P = .0437) as well as OS in both the treated (P = .045) and untreated groups (P = .012). Objective response was observed in 3 of 32 patients (9.4%) who received therapy post-EV.

Conclusion: Outcomes of patients with mUC following discontinuation of EV are dismal and only 51% received therapy after discontinuation of EV. This study identifies benchmarks for the interpretation of activity of new agents following EV and raises the hypothesis for duration of EV as a potential prognostic factor following discontinuation of EV.