Meta-analysis of the Efficacy and Tolerability of Immune Checkpoint Inhibitors Combined With Chemotherapy in First-line Treatment of Small Cell Lung Cancer

Purpose: The present study was conducted to evaluate the efficacy and tolerability of using an immune checkpoint inhibitor (ICI; programmed cell death protein 1/ligand 1 [PD-1/PD-L1] inhibitor or cytotoxic T-lymphocyte antigen [CTLA]-4 inhibitor) combined with chemotherapy in the first-line treatment of small cell lung cancer. Methods: Potential articles and studies were identified using Web of Science, Cochrane Library, and ClinicalTrials.gov. The end points included overall survival, progression-free survival, objective response rate, and adverse events. Significant heterogeneity was represented by a P value (P-h) of <0.05 or an I-2 value of >= 50%, and the random-effects model was applied for pooled analysis. Otherwise, the fixed-effects model was used. Subgroup analysis was performed based on the type of ICI. Potential publication bias was evaluated via funnel plot and the Egger test. Findings: Five eligible articles were included. Both overall survival (hazard ratio [HR] = 0.83; 95% CI, 0.75-0.91; P < 0.001) and progression-free survival (HR = 0.80; 95% CI, 0.73-0.86; P < 0.001) were significantly prolonged by joint ICI + chemotherapy treatment. Additionally, the rates of tolerable grade >= 3 adverse events were similar between the ICI combination regimens and conventional chemotherapy (relative risk = 1.05; 95% CI, 0.98-1.12; P = 0.17). Subanalysis demonstrated that patient survival and objective response rate were more efficiently improved with a combination of anti-PD-1/PD-L1, but not anti-CTLA-4, + chemotherapy. Published by Elsevier Inc.