Anti-interleukin 5 Therapy for Eosinophilic Asthma: a Meta-analysis of Randomized Clinical Trials

Recently, more and more clinical trials have been performed to evaluate the effects of anti-interleukin (IL)-5 antibodies in eosinophilic asthma. However, a confirm conclusion has not been well established. We therefore sought to conduct a meta-analysis to assess the overall efficacy and safety of anti-interleukin 5 treatments in eosinophilic asthma. RCTs of anti-interleukin 5 treatments in eosinophilic asthma published up to June 2016 in PubMed, Embase, Cochrane library databases, and CBM, which reported pulmonary functions, quality-of-life scores, asthmatic exacerbations, and adverse events were included. Fixed-effect models were used to calculate mean difference, relative risks (RR), and 95 % CIs. Twelve studies involving 3340 patients were identified. Pooled analysis revealed significant improvements in FEV₁ (nine trials, 1935 subjects; MD = 0.12; 95 % CI, 0.08-0.16), and Asthma Quality-of-Life Questionnaire scores (five trials, 1334 subjects; MD = 0.23; 95 % CI, 0.13-0.34). Anti-interleukin 5 treatment was also associated with significantly decreased exacerbation risk than placebo (six trials, 875 subjects; RR = 0.52; 95 % CI, 0.46 to 0.59) and a lower incidence of adverse events (eight trials, 1754 subjects; RR = 0.93; 95 % CI, 0.89 to 0.97). Anti-interleukin 5 treatment is well tolerated and could significantly improve FEV₁, quality of life, and reduced exacerbations risk in patients with eosinophilic asthma. Further trials are necessary to assess the baseline blood eosinophil count to identify the optimal patients of eosinophilic asthma that could benefit from anti-interleukin 5 therapy.