Abstract
Background: Cysteinyl leukotrienes mediate signs and symptoms of asthma. In a double-blind, placebo-controlled, crossover study, a new potent and specific cysteinyl leukotriene (LTD4) receptor antagonist, montelukast (MK-0476), was evaluated for tolerability and clinical efficacy in patients with chronic asthma (receiving and not receiving inhaled corticosteroids). Methods: Twenty-nine nonsmoking patients with asthma (15 treated concomitantly with inhaled corticosteroids) with FEV1 percent predicted values between 50% to 80% received MK-0476, 200 mg, or placebo three times daily for 101/3 days (31 doses) in a random, crossover manner, after a 2-week, open, baseline period. Comparisons in FEV1 (mean percent change from baseline after the first and last dose), mean daily daytime asthma and nocturnal awakening scores, and mean daily β-agonist use were made between treatment periods. Results: Montelukast, compared with placebo, caused improvements in FEV1 (mean percentage point difference of the percentage change from baseline) 3 and 4 hours after dosing on day 1 (hour 3, 9.0%; 95% confidence interval [CI] 0.53, 18.72; hour four, 10.9%; 95% CI - 0.25, 20.20) and day 11 (hour 3, 14.0%; 95% CI 0.76, 31.43; hour 4, 13.4%; 95% CI 1.24, 28.83). Reductions were observed in mean daily β-agonist use (1.0 puff/day [95% CI -1.61, -0.26]), mean daytime symptom scores, and nocturnal awakenings over the 101/3 day treatment period. There were no important differences between the groups receiving and those not receiving inhaled corticosteroids. Montelukast was well tolerated with no serious clinical adverse events reported. Conclusions: In this study Montelukast, 200 mg, administered three times daily for 101/3 days, compared with placebo, was generally well tolerated and resulted in significant improvement in chronic asthma, irrespective of the presence of inhaled corticosteroids.