Abstract
Objective: This study aims to perform systematic review and meta-analysis of all randomized controlled trials that compare the efficacy and safety of programmed death 1 (PD-1) inhibitors versus chemotherapy alone in previously untreated advanced non-small cell lung cancer (NSCLC). Materials and methods: Several databases, including Medline, Cochrane Library, Embase, and Web of Science, were searched. The main outcome measures included overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and adverse events (AEs). Results: The results of meta-analysis are expressed as the hazard ratio (HR) or risk ratio (RR) with their corresponding 95% confidence intervals (CIs). The final analysis included six trials for 3,930 patients. PD-1 inhibitors led to a statistically superior survival benefit over chemotherapy in patients with advanced NSCLC. OS was longer in patients who received PD-1 inhibitors (HR =0.71, 95% CI =0.62-0.74, P=0.000). Furthermore, PD-1 inhibitors had significantly higher objective response rate than chemotherapy (RR =0.20，95% CI =0.17-0.23, P=0.000). Meta-analysis showed that the AEs of any grade with PD-1 inhibitors were lower than those with chemotherapy (RR =0.78; 95% CI =0.75-0.81, P=0.000). Conclusion: PD-1 inhibitors showed a clinically meaningful survival benefit and an improved safety profile in patients with previously treated NSCLC.