Powles T, Park SH, Voog E, et al. - Researchers undertook this phase 3 trial to evaluate outcomes of best supportive care with or without maintenance avelumab in patients with unresectable locally advanced or metastatic urothelial cancer who did not have disease progression with first-line chemotherapy (four to six cycles of gemcitabine plus cisplatin or carboplatin). In the avelumab group and in the control group, the overall survival at 1 year was estimated to be 71.3% and 58.4%, respectively. Overall survival in the programmed cell death ligand 1–positive population was also significantly prolonged by avelumab. In this study sample, a significant prolongation of overall survival was shown to be conferred by maintenance avelumab plus best supportive care vs best supportive care alone.