Anti-IL-5 treatments in patients with severe asthma by blood eosinophil thresholds: Indirect treatment comparison

Background: Three anti-IL-5 pathway-directed therapies are approved for use in patients with severe eosinophilic asthma (SEA); however, no head-to-head comparison data are available. Objective: We sought to compare the efficacy of licensed doses of mepolizumab, benralizumab, and reslizumab in patients with SEA, according to baseline blood eosinophil counts. Methods: This indirect treatment comparison (ITC) used data from a Cochrane review and independent searches. Eligible studies were randomized controlled trials in patients aged 12 years or greater with SEA. End points included annualized rate of clinically significant exacerbations and change from baseline in Asthma Control Questionnaire score and FEV1. An ITC was performed in patients with Asthma Control Questionnaire scores of 1.5 or greater and stratified by baseline blood eosinophil count. Results: Eleven studies were included. All treatments significantly reduced the rate of clinically significant exacerbations and improved asthma control versus placebo in all blood eosinophil count subgroups. Mepolizumab reduced clinically significant exacerbations by 34% to 45% versus benralizumab across subgroups (rate ratio >= 400 cells/mu L: 0.55 [95% CI, 0.35-0.87]; >= 300 cells/mu L: 0.61 [95% CI, 0.37-0.99]; and >= 150 cells/mu L: 0.66 [95% CI, 0.49-0.89]; all P <.05) and by 45% versus reslizumab in the 400 cells/mu L or greater subgroup (rate ratio, 0.55 [95% CI, 0.36-0.85]; P =.007). Asthma control was significantly improved with mepolizumab versus benralizumab (all subgroups: P <.05) and versus reslizumab in the 400 cells/mu L or greater subgroup (P =.004). Benralizumab significantly improved lung function versus reslizumab in the 400 cells/mu L or greater subgroup (P =.025). Conclusions: This ITC of the licensed doses suggests that mepolizumab was associated with significantly greater improvements in clinically significant exacerbations and asthma control compared with reslizumab or benralizumab in patients with similar blood eosinophil counts.