Increased tumour necrosis factor-a levels have been observed in bronchial biopsies and induced sputum from subjects with severe asthma. We investigated etanercept (ETN) as a therapeutic option for treating moderate-to-severe persistent asthma.In this 12-week, randomised, double-blind, placebo-controlled, phase 2 trial, subjects (n5132) with moderate-to-severe persistent asthma received subcutaneous injections of 25 mg ETN or placebo twice weekly, and were evaluated at baseline, and at weeks 2, 4, 8 and 12. The primary end-point was the change from baseline to week 12 in pre-bronchodilator forced expiratory volume in 1 s (FEV1) % predicted. Secondary end-points included morning peak expiratory flow, FEV1 % pred, Asthma Control Questionnaire (5-item version), asthma exacerbations, provocative concentration of methacholine causing a 20% decrease in FEV1, and the Asthma Quality of Life Questionnaire.No significant differences were observed between ETN and placebo for any of the efficacy endpoints. ETN treatment was well tolerated, with no unexpected safety findings observed during the study.Clinical efficacy of ETN was not shown in subjects with moderate-to-severe persistent asthma over 12 weeks. However, ETN treatment was a well-tolerated therapy. Studies in specific subsets of patients with asthma with longer-term follow-up may be needed to fully evaluate the clinical efficacy of ETN in this population.