Meta-analysis of asthma-related hospitalization in mepolizumab studies of severe eosinophilic asthma

Background: Studies show that mepolizumab can reduce the frequency of clinically significant exacerbations in patients with severe eosinophilic asthma, compared with placebo. However, important events such as hospitalizations and emergency room visits are rare and difficult to characterize in single studies. Objective: We sought to compare hospitalization or hospitalization and/or emergency room visit rates in patients with severe eosinophilic asthma treated with mepolizumab or placebo in addition to standard of care for at least 24 weeks. Methods: This study was conducted and reported in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses statement. PubMed and the GSK Clinical Study Register were searched for suitable studies. The primary end points were the rate of exacerbations requiring hospitalization and the rate of exacerbations requiring hospitalization/emergency room visit. The proportion of patients with 1 or more event was also assessed. All mepolizumab doses were combined and individual patient-level data were analyzed. Results: Four studies (n = 1388) were eligible for inclusion. Mepolizumab significantly reduced the rate of exacerbations requiring hospitalization (relative rate, 0.49; 95% CI, 0.30-0.80; P = .004) and hospitalization/emergency room visit (relative rate, 0.49; 95% CI, 0.33-0.73; P < .001) versus placebo. Significant reductions of 45% and 38% were also observed for the proportion of patients experiencing 1 or more hospitalization and hospitalization and/or emergency room visit, respectively. Conclusions: Mepolizumab approximately halved exacerbations requiring hospitalization and/or emergency room visits compared with placebo in patients with severe eosinophilic asthma. This treatment addresses a key outcome in a patient population with a high unmet need (GSK Study 204664).