Safety and effectiveness of pembrolizumab monotherapy in Japanese patients with unresectable urothelial carcinoma: a nation-wide post-marketing surveillance

BACKGROUND: This study was conducted to identify factors associated with the safety and effectiveness of pembrolizumab in Japanese patients with unresectable urothelial carcinoma and to confirm the real-world safety and effectiveness of pembrolizumab in Japanese patients. METHODS: This multicenter, observational, post-marketing surveillance was conducted over a 1-year observation period starting at pembrolizumab initiation (200-mg pembrolizumab every 3 weeks); data were collected from case report forms (3 months and 1 year). Safety measures included treatment-related adverse events and adverse events of special interest (AEOSI). Effectiveness assessments included tumor response, objective response rate (ORR), and disease control rate (DCR). RESULTS: Overall, 1293 patients were evaluated for safety and 1136 for effectiveness. At 12 months, the treatment-related adverse event incidence was 53.8% (n = 696) and that of AEOSI was 25.0% (n = 323). The most frequent AEOSI of any grade were endocrinological disorder (10.4%, n = 134), interstitial lung disease (ILD) (7.2%, n = 93), and hepatic function disorder (4.9%, n = 64). Multivariate analysis demonstrated that the risk of developing ILD was almost seven times greater (odds ratio 6.60) in patients with a comorbidity of ILD, and approximately twice as high in patients aged ≥ 65 years (odds ratio 2.24) and with smoking history (odds ratio 1.79). The ORR was 26.1% and the DCR was 50.7%. The ORR was 46.4% in patients with a Bellmunt risk score of 0 and decreased as the Bellmunt risk score increased. CONCLUSIONS: This post-marketing surveillance confirmed the safety and effectiveness of pembrolizumab in Japanese patients with unresectable urothelial carcinoma in the real-world setting. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12885-023-10930-2.