Effectivity and safety of PD-1/PD-L1 inhibitors for different level of PD-L1-positive, advanced NSCLC: A meta-analysis of 4939 patients from randomized controlled trials

Background: Effective improvement for the programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) inhibitors had been shown in advanced non-small cell lung cancer (NSCLC) patients compared with traditional therapy. However, we do not have ample evidences to demonstrate the safety and effectivity in the treatment of PD-L1-positive, advanced NSCLC. The relation was controversial about the expression of PD-L1 and survival outcomes of PD-1/PD-L1 inhibitors. Materials and methods: Electronic databases (PubMed, EMBASE, and the Cochrane library) and major conference proceedings were systematically searched for all clinical trials in NSCLC using PD-1/PD-L1 inhibitors. Randomized controlled trials (RCTs) were included to compare PD-1/PD-L1 inhibitors with chemotherapy in advanced NSCLC patients reporting adverse events (AEs) and immune-related AEs (irAEs). The incidence, Hazard Ratio (HR), Odds Ratio (OR), and corresponding 95% confidence interval (CI) of outcomes were calculated. Results: A total of 4939 patients from 10RCTs were included. In the group of PD-L1 >= 1%, PD-L1 >= 5%, PD- L1 >= 10%, PD-L1 >= 50%, the HR of OS is 0.31(95%CI 0.38-0.23; p < 0.0001), 0.47(95%CI 0.82-0.12; p = 0.008), 0.85(95%CI 1.17-0.53; p < 0.0001), 0.47(95%CI 0.59-0.36; p < 0.0001) respectively. The HR of PFS is 0.13(95%CI 0.01-0.24; p = 0.027), 0.31(95%CI 0.00-0.62; p < 0.0001), 0.62(95%CI 0.30-0.93; p < 0.0001), 0.40(95% CI 0.20-0.59; p < 0.0001) respectively. In terms of summary adverse events, PD-1/PD-L1 inhibitors groups had a significant lower risks in any treat-realated AEs than chemotherapy. About irAEs, PD-1/PD-L1 inhibitors groups had a significant higher risks in irAEs than chemotherapy. Conclusion: PD-1/PD-L1 inhibitors are generally effected and safer than chemotherapy for patients with PD-L1-positive, advanced NSCLC. However, PD-1/PD-L1 inhibitors can generate a unique spectrum of irAEs, and even life-threatening.