Merck (NYSE:MRK), known as MSD outside the United States and Canada, today announced results from the pivotal KEYNOTE-045 study investigating the use of KEYTRUDA ® (pembrolizumab), the company's anti-PD-1 therapy, in patients with advanced bladder (urothelial) cancer previously treated with platinum-containing chemotherapy. As previously announced, KEYTRUDA was superior to investigator-choice chemotherapy for the primary endpoint of overall survival (OS) in this phase 3 study, and was stopped early. Specifically, there was a 27 percent reduction in the risk of death in patients treated with KEYTRUDA compared to chemotherapy (OS, HR = 0.73, p-value: 0.0022). Data presented at the Society for Immunotherapy of Cancer's (SITC) 31 st Annual Meeting are the first publicly presented findings from this study. "The improved overall survival for patients receiving KEYTRUDA in this trial are clinically significant and could impact how physicians consider treating patients with previously treated advanced urothelial cancer," said Dr. Roger Dansey, senior vice president, oncology late-stage development, Merck Research Laboratories. "These data add to the growing body of evidence from our clinical development program for KEYTRUDA in a range of cancers, including advanced urothelial cancer." Study findings are being presented by Dr. Joaquim Bellmunt from Dana-Farber Cancer Institute on Saturday, Nov. 12 th from 11:45 a.m. - 12:00 p.m. ET (Abstract #470). "There have been few advancements in the treatment of bladder cancer in the past several decades, with chemotherapy being the only option," said Dr. Dean F. Bajorin, study investigator and medical oncologist at Memorial Sloan Kettering Cancer Center. "These data demonstrate the potential for pembrolizumab to provide a meaningful improvement in overall survival for patients with advanced urothelial cancer who previously have received platinum-containing chemotherapy." The KEYTRUDA (pembrolizumab) clinical development program includes more than 30 tumor types in more than 360 clinical trials, including nearly 200 trials that combine KEYTRUDA with other cancer treatments. Currently, Merck has the largest immuno-oncology clinical development program in bladder cancer, with 27 trials underway involving KEYTRUDA as monotherapy and in combination, including four registration-enabling studies.