Thomas Powles, MBBS, MRCP, MD, from the Barts Cancer Institute, London, UK, gives an overview of the KEYNOTE-052 (NCT02335424) trial of pembrolizumab in urothelial bladder cancer at the European Association of Urology (EAU) conference 2017 in London, UK. This Phase II trial is investigating pembrolizumab treatment in urothelial bladder cancer patients ineligible for cisplatin-based chemotherapy. Prof. Powles explains that historically, the majority of patients in this setting have been treated with chemotherapy, and cisplatin is the standard approach in this case, however a substantial proportion of patients are not fit enough or have insufficient renal function for this treatment. Pembrolizumab was tested in 370 patients, with a 24-27% response rate (RR) observed. This response rate was enriched to 48% in patients with PD-L1 positive tumors. According to Prof. Powles, long-term and durable responses were seen, and the treatment was generally well tolerated, with a 16% Grade III and IV adverse event rate. He argues that in pembrolizumab, we have a drug with significant activity and good tolerability in an area of unmet need. It is likely that patients will want this treatment, and doctors will want to prescribe it, and he is confident that FDA approval of pembrolizumab for this indication will be granted.