Background: Several ongoing phase III studies are evaluating the efficacy of first-line atezolizumab in combination with chemotherapy in patients with non small-cell lung cancer (NSCLC). Among angiogenesis inhibitors, bevacizumab is approved as first-line therapy in combination with chemotherapy or in combination with erlotinib in patients with NSCLC harboring activating EGFR mutations. Recent evidence (Wallin 2016) suggests that the combination of atezolizumab and bevacizumab increases intra-tumoral CD8+T cells, suggesting that dual VEGF and PD-L1 inhibition improves antigen-specific T-cell migration. In addition, preliminary clinical data suggested a strong synergistic effects of bevacizumab with immune checkpoint inhibitors. There is therefore a strong rationale for investigating the combination of atezolizumab and bevacizumab in patients with advanced/metastatic NSCLC. The FoRT 05-BEAT is a multicenter, Italian, phase II, randomized study comparing atezolizumab monotherapy versus the combination of atezolizumab and bevacizumab in patients with chemo-naive metastatic NSCLC and high levels of PD-L1 expression. Methods: The trial was conducted in 35 Italian centers: chemotherapy naive metastatic NSCLC patients, with high levels of PD-L1 expression (PD-L1 TPS ≥50% or TC/IC 3 scoring) were randomly assigned to atezolizumab monotherapy (1200 mg every 3 weeks) or to the combination of atezolizumab (1200 mg every 3 weeks) and bevacizumab (15 mg/kg every 3 weeks).The primary endpoint is overall survival (OS) rate at 18 months. Secondary endpoints include response rate (RR), PFS, OS according to presence of bone and/or hepatic metastases. Safety considerations will be considered. Exploratory analysis of predictive biomarker on tumor tissue and blood samples has been planned. Sample size has been calculated assuming a 18 months OS of 50% in the atezolizumab arm. Therefore, a total of 186 patients is needed to detect an absolute improvement of 20%, thus obtaining a 18mOS of 70% in the combination arm, with a power of 80% at a significance level of 5%. Taking into account the percentage of patients lost-to-follow-up, the sample size has been increased by 10% (N = 206 patients, 103 per arm). At the drafting of this abstract, 57 patients have already been enrolled (47 randomized). Clinical trial information: NCT03896074.