Efficacy and safety of mepolizumab in patients with severe eosinophilic asthma: a meta-analysis

Background: The efficacy and safety of mepolizumab in patients with eosinophilic asthma remains controversial. Our meta-analysis was undertaken to evaluate the efficacy and safety of mepolizumab in patients with eosinophilic asthma. Methods: PubMed, EMBASE, Cochrane Library, and Clinical Trials.gov databases were searched for randomized controlled trials (RCTs). The incidence of exacerbation was the efficacy endpoint. The safety endpoint was the incidence of adverse events. Results: Eight RCTs and 1818 patients were included in our meta-analysis. Mepolizumab associated with lower risk compared with placebo in the endpoint of exacerbation when a dose of 750 mg was used (Risk Ratio (RR) 0.77 95% confidence intervals (CIs) 0.60 to 0.98; P=0.03; I-2=48%) and similar results were obtained with a dose of 100 mg (RR 0.58 95% CI 0.44 to 0.78; P=0.0003; I-2=0). The risk of adverse events was decreased compared with placebo at the dose of 50 mg (RR 0.72 95% CI 0.53 to 0.99; P=0.05; I-2=0). In the subgroup analysis of a 250 mg dose (standard mean differences (SMD) 2.00; 95% CI 1.72 to 2.27; P<0.00001) and a 100 mg dose (SMD 3.71; 95% CI 1.28 to 6.14; P=0.003; I-2=99%), mepolizumab significantly increased the value of FEV1 more than placebo. Meanwhile mepolizumab associated with greater decrease in blood eosinophil counts but did not confer a significant difference in the change of sputum eosinophil counts and Asthma Control Questionnaire (ACQ). Conclusion: Mepolizumab associated with a significant reduction in endpoint of exacerbation and adverse events, but an increased value of FEV1. Meanwhile, mepolizumab-treated patients experienced significant decreases in blood eosinophil levels and ACQ compared with those who received placebo.