Efficacy and safety of pembrolizumab for treating advanced non-small-cell lung cancer: a meta-analysis of phase II and III randomized controlled trials

＜ 0.00001) than chemotherapy. Patients with higher PD-L1 expression level were tend to have a better PFS, OS and ORR. Combination therapy of pembrolizumab was superior to pembrolizumab monotherapy in enhancing PFS. Pembrolizumab did not increase the frequency of commonly reported adverse events, but the immune-related adverse events (irAEs) occurred more frequently in the pembrolizumab group than those in the chemotherapy group. The pembrolizumab significantly improved the PFS, OS and ORR, simultaneously increasing the irAEs.