(UroToday.com) In the phase 3 JAVELIN Bladder 100 trial, avelumab first-line maintenance + best supportive care significantly prolonged overall survival versus best supportive care alone in patients with advanced urothelial carcinoma that had not progressed on first-line platinum-based chemotherapy (HR 0.69, 95% CI 0.56 to 0.86; 1-sided p = 0.0005).1 Based on these results, avelumab first-line maintenance was approved in the USA, Canada, Europe, Japan, etc for patients who are progression-free following platinum-based chemotherapy. At the 2021 American Society of Clinical Oncology (ASCO) 2021 Annual Meeting, Dr. Thomas Powles and colleagues presented results of post hoc analyses in previously unreported clinical and genomic subgroups.