Addition of leukotriene antagonists to therapy in chronic persistent asthma: a randomised double-blind placebo-controlled trial

Background Controlled trials suggest that leukotriene receptor antagonists can improve lung function and reduce requirement for oral or inhaled corticosteroids in patients with asthma. We aimed to assess whether montelukast, a leukotriene receptor antagonist, can improve symptoms or lung function in patients with chronic asthma with symptoms already taking corticosteroids. Methods We did a double-blind, placebo-controlled, crossover, randomised add-on study in which 100 patients with asthma and symptoms despite treatment with inhaled corticosteroids and additional therapy were given 10 mg montelukast sodium for 14 days in an outpatient clinic setting. Outcome measures were symptoms and peak flow diaries. Findings 72 patients had diary data for analysis. Compared with placebo, addition of montelukast did not result in any significant change in symptom scores (mean difference between the last 7 days of each treatment period 0·05; 95% CI −0·86 to 1·14), rescue inhaled (32 agonist use (mean difference in puffs per day 0·41; −0·29 to 0·57), or twice daily peak expiratory flow (PEF) measurements (mean difference in morning PEF 1·18 L/min; −14·29 to 17·14), and mean difference in evening peak flow (-0·50; −17·42 to 12·86). When treatment response was defined as a 15% or greater increase in mean peak flow readings, there were four responders to montelukast and seven responders to placebo. Interpretation Based on PEF data from our previous studies of a similar patient group we would have expected to detect changes of more than 5%. Used as additional therapy in a hospital outpatient clinic setting, montelukast did not provide such additional benefit in patients with moderate or severe asthma.