Pseudoprogression During Enfortumab Vedotin Plus Pembrolizumab Therapy in Muscle‐Invasive Bladder Cancer Achieving Pathological Complete Response: A Case Report

ABSTRACT Introduction Enfortumab vedotin plus pembrolizumab has emerged as a standard first‐line therapy for advanced urothelial carcinoma (UC). However, pseudoprogression during this combination remains poorly characterized. Case Presentation A 71‐year‐old man with muscle‐invasive bladder cancer and lymph node metastasis received enfortumab vedotin plus pembrolizumab. During treatment, imaging suggested tumor progression with new hydronephrosis. Repeat transurethral resection revealed no viable tumor. Because of persistent symptoms, robot‐assisted radical cystectomy was performed. Histopathological examination demonstrated no residual tumor cells, indicating pathological complete response (ypT0N0), with prominent CD8‐ and CD4‐positive T‐cell infiltration and minimal CD20‐positive B‐cell infiltration. Conclusion This case suggests that pseudoprogression may occur during enfortumab vedotin plus pembrolizumab therapy. Careful interpretation of radiological findings is essential to avoid premature treatment discontinuation.