Efficacy and Safety of Anti-Interleukin-5 Therapy in Patients with Asthma: A Systematic Review and Meta-Analysis

BACKGROUND Recent trials have assessed the efficacy and safety of novel monoclonal antibodies such as reslizumab and benralizumab. However, the overall efficacy and safety anti-interleukin (IL) 5 treatment in asthma have not been thoroughly assessed. METHODS Randomized controlled trials (RCTs) of anti-IL-5 treatment on patients with asthma published up to October 2016 in PubMed, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) that reported pulmonary function, quality of life scores, asthmatic exacerbation rate, blood and sputum eosinophil counts, short-acting β-agonist (SABA) rescue use, and adverse events were included. The pooled mean difference, and relative risks (RR), and 95% confidence intervals (CIs) were calculated using random-effects models. RESULTS Twenty studies involving 7100 patients were identified. Pooled analysis revealed significant improvements in FEV1 (first second forced expiratory volume) (MD = 0.09, 95% CI: 0.06-0.12, I2 = 10%), FEV1% (MD = 3.75, 95% CI: 1.66-5.83, I2 = 19%), Asthma Quality of Life Questionnaire (AQLQ) score (MD = 0.22, 95% CI: 0.15-0.30, I2 = 0%), decreased blood, sputum eosinophils and asthmatic exacerbation (RR = 0.66, 95% CI: 0.59-0.73, I2 = 51%); peak expiratory flow (PEF) (MD = 5.45, 95% CI: -2.83-13.72, I2 = 0%), histamine PC20 (MD = -0.62, 95% CI: -1.92-0.68, I2 = 0%) or SABA rescue use (MD = -0.11, 95% CI: -0.3-0.07, I2 = 30%) were unaffected; adverse events were not increased (RR = 0.93, 95% CI: 0.89-0.98, I2 = 46%). No publication bias was observed (Egger's P = 0.78). CONCLUSIONS Anti-interleukin 5 monoclonal therapies for asthma could be safe for slightly improving FEV1 (or FEV1% of predicted value), quality of life, and reducing exacerbations risk and blood and sputum eosinophils, but have no significant effect on PEF, histamine PC20, and SABA rescue use. Further trials required to establish to clarify the optimal antibody for different patients.