Zafirlukast improves asthma symptoms and quality of life in patients with moderate reversible airflow obstruction

Background: Previous trials demonstrated the effectiveness of the leukotriene receptor antagonist zafirlukast in patients with mild-to-moderate asthma. Objectives: We sought to assess the efficacy and safety of zafirlukast and its effect on patients' quality of life (QOL) during a 13-week, double-blind, placebo-controlled, multicenter trial in adults and adolescents with moderate reversible airflow obstruction. Methods: Patients (age range, 12 to 68 years) with total daytime asthma symptoms scores of 10 or greater over 7 consecutive days (maximum, 21/wk), FEV₁ 45% or greater but less than or equal to 80% of predicted value (≥6 hours after β₂-agonist), and reversible airway disease were randomized to 20 mg zafirlukast twice daily (n_Z = 231) or placebo twice daily (n_P = 223). Efficacy was assessed from changes in daytime and nocturnal symptoms, β₂-agonist use, nasal congestion score, and pulmonary function. QOL was evaluated with a disease-specific Asthma Quality of Life Questionnaire. Safety was determined from adverse event information and clinical laboratory test results. Results: Zafirlukast was significantly (P < .001) more effective than placebo, with reductions from baseline in the daytime asthma symptoms score (-23%), nighttime awakenings with asthma (-19%), and β₂-agonist use (-24%) and improvements from baseline in morning (+25 L/min) and evening (+18 L/min) peak expiratory flow rates. Compared with placebo, zafirlukast significantly (P ≤ .018) improved scores for QOL domains (activity limitations, symptoms, emotional function, and exposure to environmental stimuli) and overall QOL, with a significantly greater proportion of zafirlukast-treated patients demonstrating clinically meaningful improvements (≥0.5-unit change from baseline; P ≤ .037). The safety profile of zafirlukast was clinically indistinguishable from that of placebo. Conclusions: Zafirlukast is effective and well tolerated and improves QOL in the long-term treatment of patients with moderate reversible airflow obstruction.