Real-world experience with atezolizumab (atezo) in advanced urothelial cancer (UC).

e16031Background: Atezo was recently FDA-approved for patients (pts) with UC (IMvigor210 trial). We assessed the safety and efficacy of Atezo in the real world setting and explored the role of putative biomarkers. Methods: Data from 44 consecutive non-trial pts with UC treated with ≥1 dose of Atezo 1200mg IV q3w at Cleveland Clinic (May - Dec 2016) were available. Demographic, clinicopathologic, biomarker data, including blood neutrophil to lymphocyte ratio (NLR) and myeloid derived suppressor cell (MDSC) populations [LinloCD33+/HLADR-(Total), and Granulocytic(CD15+CD14-), Monocytic(CD15-CD14+), Immature(CD15-CD14-), CD11b+ subsets], were collected. Response, progression-free survival (PFS) and overall survival (OS) were measured (RECIST v1.1). Adverse events (AE) were reported (CTCAE v4.03). Outcome data were analyzed with Fisher’s exact test, chi-square tests, log rank test and proportional hazards models. Results: Median age was 68y (34-88), 68% men, 68% pure urothelial histology, 27% never smokers; 61...