Pembrolizumab Maintenance After Enfortumab Vedotin (EV)/Pembro Induction in Front-Line Metastatic Urothelial Carcinoma

This is a single-arm, open-label, non-randomized Phase II trial evaluating the efficacy of induction therapy with enfortumab vedotin (EV) plus pembrolizumab (P) for 18 weeks (6 cycles), followed by maintenance pembrolizumab in treatment-naïve patients with metastatic urothelial carcinoma (mUC). Approximately 97 patients will be enrolled. Induction consists of EV (1.25 mg/kg IV on Days 1 and 8 of each 21-day cycle; starting dose of 1 mg/kg allowed) and P (200 mg IV on Day 1 of each cycle). Radiographic assessments occur after 3 and 6 cycles. Patients achieving complete or partial response transition to maintenance P (400 mg IV every 6 weeks or 200 mg IV every 3 weeks) for up to 2 years. Dose modifications for EV are permitted per protocol; no dose adjustments for P. Treatment continues until disease progression, unacceptable toxicity, or completion of maintenance therapy. Patients will enter long-term or survival follow-up as applicable.