Outcomes of patients (pts) with advanced urothelial carcinoma (aUC) treated with immune checkpoint inhibitors (ICIs): Associations with age, race, sex and smoking history

e16526 Background: ICIs have altered the therapeutic landscape in pts with aUC and new biomarkers are needed to better predict response and outcomes with ICIs. It is unclear whether demographics, such as race, age, sex and history of smoking, are associated with outcomes with ICIs. We hypothesized that specific demographic groups (sex, age, race, smoking history) would be associated with outcomes with ICIs in aUC. Methods: We performed a retrospective cohort study across 25 institutions. Data collected included demographic and clinicopathologic factors, response and outcomes. We calculated observed response rate (ORR), Progression-Free Survival (PFS) and overall survival (OS) for specific demographic groups. We built multivariable models (logistic regression for ORR; Cox regression for PFS and OS) with all demographic groups to assess outcomes. Analysis was done for the overall population and stratified by treatment line (first line [1L]; salvage [2+L]). The stratified analysis was also adjusted for known prognostic risk scores (internally developed for 1L; Bellmunt for 2+L); p-value < 0.05 was significant. Results: We identified 1026 pts; 754, 744 and 780 were included in OS, ORR and PFS analysis. Overall, median age at ICI initiation was 70; 26% female; 75% White, 11% Hispanic, 5% Black, 8% other; 69% had smoking history; 28% with mixed histology; 17% with upper tract UC. In the unstratified analysis, age 65-74 (vs < 65) was significantly associated with higher ORR (32% vs 22%) and median PFS (5 vs 3 mo HR 0.8); otherwise no significant difference was noted among groups for ORR, PFS, OS in both the stratified and unstratified analyses (Table). Conclusions: We did not identify significant associations between age, sex, race or smoking history and ORR, PFS, OS with ICIs in pts with aUC. Limitations include retrospective nature, lack of randomization, possible selection and confounding factors. Further research is required to identify prognostic and predictive biomarkers for ICI therapy in aUC.[Table: see text]