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.

Abstract

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 PD-L1 status (VENTANA SP142) and age in the overall population (and the IMvigor211-like subgroup for PD-L1). Results: Between Nov 2016 and Mar 2018, 1004 pts were enrolled; 997 received atezo. Efficacy is summarized below. Incidences of grade ≥3 treatment-related adverse events were similar irrespective of PD-L1 status (overall IC 0/1 vs 2/3: 11% vs 16%; IMvigor211-like IC 0/1 vs 2/3: 11% vs 15%) or age (≥65 y: 13%; ≥75 y: 12%; ≥80 y: 10%). Conclusions: OS and ORR appear more favorable in IC 2/3 vs IC 0/1 subgroups (overall and in the IMvigor211-like population). Atezo was effective and well tolerated across subgroups including elderly pts. Clinical trial information: NCT02928406. [Table: see text]