Real-World Clinical Outcomes of Pembrolizumab as Second-Line Therapy for Advanced Urothelial Carcinoma

Background: Pembrolizumab is currently considered the standard second-line treatment for advanced urothelial carcinoma (UC). This study aimed to investigate the efficacy and safety of pembrolizumab in patients with advanced UC in real-world data, which is not well-reported.Methods: The study included 98 patients with advanced UC who were treated with pembrolizumab after platinum-based chemotherapy at eight hospitals. The efficacy, safety, and risk factors for prognosis were evaluated. Results: The median age was 73 years. Nineteen patients (19%) with performance status (PS) 2-4 were included. The percentages of liver, lung, bone, and lymph node metastasis were 18%, 27%, 19%, and 76%, respectively. The best response was complete response in nine patients (9%) and partial response in 16 patients (17%). The median progression-free survival and overall survival were 3.7 months (95% confidence interval [CI]: 2.8–4.7) and 11.8 months (95% CI: 6.7–17.0), respectively. Poor PS, liver metastasis, and higher C-reactive protein were poor prognostic factors. Hyperprogression was observed in nine patients (9%), who were mostly of poor PS and had high-volume lesions. Severe adverse events (AEs) were observed in 18 patients (19%), and five patients died because of AEs (5%). Atypical AEs, such as pneumocystis pneumonia and acute myeloid leukemia, were observed in our cohort. Conclusion: The efficacy of pembrolizumab for advanced UC in our cohort was better than a previous phase III trial (KEYNOTE-045), possibly owing to lower cancer volume and fewer visceral metastases in our patients.