Joaquim Bellmunt, MD, PhD, from the Dana-Farber Cancer Institute, Boston, MA, summarizes the aims and results of the KEYNOTE-045 (NCT02256436) trial of pembrolizumab as a second-line agent in the treatment of urothelial carcinoma at the European Association of Urology conference 2017 in London, UK. He explains that this Phase III randomized trial was carried out in patients failing first-line platinum-base chemotherapy, or second- or third-line chemotherapy in some cases. Patients received pembrolizumab every three weeks, or standard of care chemotherapy (paclitaxel, docetaxel, or vinflunine). Dr Bellmunt highlights that this is the first trial showing an advantage of immunotherapy over chemotherapy in bladder cancer treatment. He points out other trials of immunotherapy in advanced or metastatic bladder cancer currently ongoing, such as the IMvigor211 Phase III trial comparing the PD-L1 inhibitor atezolizumab (NCT02302807) to chemotherapy, which he hopes will provide further data showing that immunotherapy is superior to chemotherapy in this setting.