Atezolizumab (Atezo) And Subsequent Therapies In Patients (Pts) With Metastatic Urothelial Carcinoma (Muc) Outside Clinical Trials.

432Background: The use of immune checkpoint inhibitors (ICI) has revolutionized treatment of mUC. Little is known about the outcomes and safety profile of pts treated with ICI outside of clinical trials, as well as about responses to subsequent therapies. Methods: A retrospective analysis of consecutive mUC pts who received ≥1 dose of atezo 1200 mg every 3 weeks from May 2016 through April 2017 was conducted. Exploratory assessments included overall response rate according to RECIST v1.1, progression-free survival (PFS) and overall survival (OS) since time of treatment initiation, and treatment-related adverse events (TRAE) according to CTCAE v4.03. Results: A total of 79 pts were identified; median age 72 (29-93), 71% men, 27% never smokers, 66% pure urothelial histology, 49% visceral disease, 76% ECOG PS 0-1 and 61% with 1-2 Bellmunt risk factors. Most pts (79%) had primary tumor in bladder, 62% prior surgery and 75% ≥ 1 prior treatment. Most pts (71%) had 1-2 prior lines of treatment, 4% of pts had 3 l...