Clinical Outcomes of Enfortumab Vedotin in Advanced Urothelial Carcinoma With Prior AvelumabVersusPembrolizumab Therapy

Background/Aim: This study retrospectively evaluated whether enfortumab vedotin (EV) monotherapy is effective as a late-line treatment according to prior treatment type in patients with advanced urothelial carcinoma (UC). Patients and Methods: We assessed consecutive patients from the Uro-Oncology Group in the Kyushu study population with lower and upper urinary tract cancer treated with EV monotherapy after platinum-based chemotherapy and immune checkpoint inhibitor therapy failure between December 2021 and March 2024. In particular, patients receiving avelumab maintenance or pembrolizumab therapy before EV for advanced UC were analyzed and compared according to the response rate, progression-free survival (PFS), and overall survival (OS). Results: Of the 80 enrolled patients, 31 and 49 received avelumab and pembrolizumab before EV therapy, respectively. The avelumab and pembrolizumab groups had comparable objective response rates (48.4% vs. 44.9%, p=0.820) and disease control rates (77.4% vs. 67.3%, p=0.448). These two groups showed no significant difference in PFS from the initiation of EV (median: 6.4 months vs. 4.2 months, p=0.184); meanwhile, the avelumab group had better OS from the initiation of EV than the pembrolizumab group (median: 16.0 months vs. 10.2 months, p=0.019). Moreover, the median OS after first-line chemotherapy initiation was longer in the avelumab group than in the pembrolizumab group (40.3 months vs. 24.7 months, p=0.054). On multivariate analysis, avelumab maintenance therapy before EV reduced the mortality risk by 47% (95% confidence interval=0.27-1.03; p=0.059). Conclusion: EV monotherapy after avelumab maintenance therapy provides favorable survival outcomes in patients with advanced UC.