Patient outcomes following disease progression with enfortumab-vedotin (EV) in metastatic urothelial carcinoma (mUC).

Abstract

e16516 Background: Enfortumab Vedotin (EV) is an antibody drug conjugate (ADC), licensed for use in metastatic urothelial carcinoma (mUC), following disease progression with platinum-based chemotherapy (ChT) and immune checkpoint inhibitors (ICIs). A patient cohort now exists with disease progression following EV with no guidance for subsequent treatment. This retrospective observational study assessed patient outcomes post EV progression. Methods: Patients were identified from 3 centres in Europe (St Bartholomew’s Hospital, University Hospital Virgen Del Rocio and Hospital Universitario 12 de Octubre). Data was collected regarding treatments prior to and post EV, length of EV treatment and overall survival (OS) post EV progression. Descriptive statistics and survival analyses comparing survival outcomes stratified by treatment post EV progression were performed in SPSS (Version 27). Results: All 24 patients had received both an ICI and ChT prior to receiving EV. 10 patients received further treatment following disease progression on EV. 8 patients received ChT (6 patients platinum based, 1 patient paclitaxel, 1 patient vinflunine), 1 patient received radical radiotherapy and 1 patient received derazantinib. No patient received further ICI therapy post EV progression. 2 patients had achieved complete radiological response with EV and had no evidence of disease progression. Point bi-serial correlation showed no significant association between length of EV treatment and receiving further treatment post disease progression on EV. There was also no significant association between pre EV survival length and further treatment post disease progression on EV. Survival analysis (Kaplain-Meier, Mantel-Cox Log Rank) revealed a statistically significant difference in mean OS. Mean OS was 1 month in patients who received no further treatment vs 7 months in patients who received treatment post progression on EV (Chi-Square 16.569, p = 0.000). Conclusions: Less than half of patients who progressed on EV received subsequent treatment. Patients who did receive treatment had significantly increased OS. There is a clear gap in literature and evidence-based guidance for treatment following EV progression and further studies are required with larger samples accounting for confounding factors to further evaluate best practise post disease progression on EV.