Background: In Study JVDF (NCT02443324), we combined ramucirumab (VEGFR2 antagonist) and pembrolizumab (PD-1 antagonist) to simultaneously target the tumor microenvironment and immune checkpoints in patients with advanced non-small cell lung cancer (NSCLC), gastric or gastroesophageal junction adenocarcinoma (G/GEJ), urothelial carcinoma (UC) or biliary tract cancer (BTC). We reported that this combination was associated with increased antitumor activity in patients with PD-L1 positive tumors by immunohistochemistry (IHC) compared with PD-L1 negative tumors.1) Here we explore the association between baseline gene expression profiles and clinical outcomes. Methods: JVDF was a nonrandomized phase 1a/b trial that treated patients with intravenous ramucirumab at 8 mg/kg on days 1 and 8 (G/GEJ, BTC) or 10 mg/kg on day 1 (G/GEJ, NSCLC, UC) plus pembrolizumab (200 mg day 1) every 3 weeks.¹ Baseline tumor samples from 53 patients across 7 study cohorts were analyzed with the NanoString PanCancer Immune Profiling Panel for RNA expression and the DAKO PD-L1 IHC 22C3 pharmDx assay for PD-L1 protein expression. Clinical outcomes included progression-free survival (PFS), overall survival (OS), and objective response rate (ORR). Results: Across cohorts, PD-L1 gene expression was correlated with increased IFNγ gene expression and immune-related gene signatures (T effector, T cell-inflamed (TIS)), and trended with PD-L1 protein expression. Expression of immune checkpoint-related genes and myeloid-derived suppressor cell /regulatory T cell markers was increased in the NSCLC TPS≥50% PD-L1 IHC subgroup (N=8), while no clear pattern of expression was observed in other cohorts. Higher T effector and TIS scores appeared associated with better survival and response in NSCLC cohorts (mean TIS: 1.21±0.80 in responders (N=7) vs -0.13±0.57 in non-responders (N=7); p=0.004), and a trend was observed in G/GEJ cohorts (mean TIS: -0.18±0.30 (N=5) vs -0.39±0.21 (N=13); p=0.207). Of note, partial responses and stable disease were also observed in NSCLC and G/GEJ patients with a low baseline inflammatory signature score. Additional analyses are ongoing and will be presented. Conclusions: Baseline PD-L1 gene and protein expression tends to correlate with immune-related gene expression, and an inflamed tumor microenvironment may be associated with better clinical outcomes with ramucirumab and pembrolizumab. However, interpretation is limited by lack of control arm and sample size.1) Herbst et al. Lancet Oncol. 2019 Aug; 20 (8):1109-1123. Clinical trial information: NCT02443324.