Treating Japanese Patients With Pembrolizumab for Platinum-Refractory Advanced Urothelial Carcinoma in Real-World Clinical Practice

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BACKGROUND: Since December 2017, pembrolizumab has been approved in Japan as a second-line treatment for radical unresectable urothelial carcinoma (UC) that has become exacerbated after chemotherapy by the international randomized phase 3 trial, KEYNOTE-045. The aim of this study was to evaluate the oncological efficacy and safety of pembrolizumab after failure of platinum-based chemotherapy in Japanese patients with advanced UC in real-world clinical practice. METHODS: A total of 34 patients who received pembrolizumab after the failure of platinum-based chemotherapy for advanced urothelial carcinoma at four institutions between January 2018 and August 2019 were retrospectively evaluated. In all patients, UC was histopathologically diagnosed, and disease progression after platinum-based chemotherapy was radiologically confirmed. RESULTS: The median follow-up period was 7.7 months. The objective response rate, median progression-free survival, and median overall survival were 20.6%, 3.3 months, and 11.7 months, respectively. Regarding the toxicities associated with pembrolizumab, adverse events (AEs) of any grade occurred in 61.8%, and grade 3 AEs occurred in 23.5%; grade ≥ 4 AEs did not occur in any patients. Univariate analyses revealed that the Eastern Cooperative Oncology Group Performance Status, neutrophil/lymphocyte ratio, liver metastases, and time from previous chemotherapy were prognostic variables. Multivariate analyses revealed that liver metastases (positive: hazard ratio, 4.23; 95% confidence interval, 1.48 - 12.08; P < 0.01) and time from previous chemotherapy (≥ 3 months: hazard ratio, 5.06; 95% confidence interval, 1.43 - 17.91; P = 0.01) were independent prognostic factors. CONCLUSIONS: In this real-world clinical study, these findings concerning the efficacy and safety of pembrolizumab for advanced UC in Japanese patients were comparable to those of the open-label, international, phase 3 trial KEYNOTE-045. Liver metastases and time from previous chemotherapy were independent prognostic factors in the present study.