Background: R (anti-VEGFR2) and P (anti-PD-1) are active in patients (pts) with previously-treated non-small cell lung carcinoma (NSCLC), gastric or gastroesophageal adenocarcinoma (G/GEJ) and urothelial carcinoma (UC). Because PD-L1 expression may be a predictive biomarker, we examined the effect of R + P in relation to PD-L1. Methods: Eligible pts had progressive advanced or metastatic G/GEJ, NSCLC and UC, ECOG PS 0-1, and baseline tumor tissue. PD-L1 was assessed using the PD-L1 IHC 22C3 pharmDx assay, where the number of stained tumor cells (tumor proportion score; TPS) or tumor and immune cells (combined positive score; CPS) is relative to total tumor cells. PD-L1 positivity was defined by CPS ≥1% in G/GEJ and UC, and defined by TPS ≥1% in NSCLC. Primary objective was safety and tolerability of R + P. Results: As of 31-July-2017, 92 pts received P 200 mg on Day 1 q3W with R at 10 mg/kg on Day 1 (G/GEJ, n = 17; NSCLC, n = 27; and UC, n = 24) or R at 8 mg/kg, Day 1 and 8 q3W (G/GEJ, n = 24). Baseline demographics and characteristics were as expected for an advanced, previously treated population. Median follow-up duration for G/GEJ, NSCLC, and UC, was 17.9 months (mo), 20.1 mo, and 17.5 mo, respectively. The safety profile was consistent with that of each individual drug, with no additive toxicities. 84 (91%) of 92 pts were evaluable for PD-L1. Objective response rate (ORR), progression-free survival (PFS), and overall survival (OS) by PD-L1 are shown in the table. 13 pts remained on study treatment (G/GEJ, n = 4; NSCLC, n = 8; and UC, n = 1). Clinical trial information: NCT02443324 NR = not reached Conclusions: In previously treated G/GEJ, NSCLC, and UC, R + P appears to provide more benefit in PD-L1 positive compared to PD-L1 negative pts. Randomized trials are warranted. Updated safety and efficacy results will be presented at the meeting.