Clinical outcomes according to PD-L1 status and age in the prospective international SAUL study of atezolizumab (atezo) for locally advanced or metastatic urothelial carcinoma (UC) or non-UC of the urinary tract.

4519 Background: Atezo, a monoclonal antibody targeting PD-L1, is an approved therapy for locally advanced/metastatic UC based on IMvigor210 and IMvigor211 phase II and III trials. The single-arm SAUL study (NCT02928406) with a broader patient (pt) population demonstrated median overall survival (OS) of 8.7 months and a safety profile consistent with previous atezo trials. Methods: Pts with locally advanced/metastatic UC or non-UC of the urinary tract received atezo 1200 mg every 3 weeks until disease progression or unacceptable toxicity. Populations excluded from IMvigor211 (renal impairment, ECOG PS 2, treated asymptomatic CNS metastases, stable controlled autoimmune disease, concomitant steroids, HIV positive, non-UC) were eligible. The primary endpoint was safety; OS and overall response rate (ORR) were secondary endpoints. Predefined subgroup analyses included outcomes according to …