Efficacy of atezolizumab to treat non-small-cell lung cancer: a meta-analysis based on randomized clinical trials.

Atezolizumab, an immunoglobulin G1 monoclonal antibody against PD-L1, is accepted to treat advanced non-small-cell lung cancer (NSCLC). Our systematic review aims to evaluate survival efficacy of atezolizumab, overall and in subgroups defined by PD-L1 expression. Search the trials on efficacy of atezolizumab in advanced NSCLC based on online electronic databases from their dates of inception up to June 2019, including PubMed, Embase and Cochrane library databases. After rigorous reviewing of quality, the data of the PFS and OS were measured as outcomes. Six trials including seven researches were included. Overall, 4722 subjects involving 2488 patients received atezolizumab and 2234 patients received investigator's choice chemotherapy were retrieved. For the intention-to-treat (ITT) population, the pooled ORs for overall survival (OS) was 0.81 (95 % confidence interval [CI] 0.75-0.87; P<0.00001) and progression-free survival benefit (PFS) was 0.65 (95 % CI 0.59-0.73; P<0.00001), respectively. For the subgroups PD-L1 expression (negative and high), there were benefits both observed in the PFS and OS in two sub-groups with atezolizumab (P 0.05). However, in the low expression of PD-L1 group, the subjects who received atezolizumab achieved PFS (OR 0.70; 95% CI: 0.58-0.84, P=0.0002) advantage but OS advantage (OR 0.91; 95% CI: 0.62-1.33, P=0.62). In low expression of PD-L1 subgroups, a benefit was observed for PFS but OS. However, the status of PD-L1 expression cannot be recommend as prognostic biomarker to support the decision who will benefit from atezolizumab.