“There is a significant unmet need for patients with advanced prostate cancer, and the outcome of this study is an important reminder that this disease remains very difficult to treat,” said Dr. Scot Ebbinghaus, vice president, clinical research, Merck Research Laboratories. “We are grateful to the patients and investigators for their participation in this study, and we will continue to advance our clinical development program to evaluate KEYTRUDA-based combinations and novel candidates for patients with prostate cancer.”