Efficacy of zileuton controlled-release tablets administered twice daily in the treatment of moderate persistent asthma: a 3-month randomized controlled study.

Background: A controlled-release (CR) formulation of zileuton was developed to simplify administration from 600 mg 4 times daily (Zyflo) to 1,200 mg twice daily.
Objective: To evaluate the efficacy of zileuton CR, two 600-mg tablets twice daily, compared with placebo.
Methods: Patients with moderate asthma treated with short-acting beta-agonists only were randomized to receive zileuton CR, 1,200 mg twice daily (n = 206); placebo CR, twice daily (n = 203); zileuton immediate-release (IR), 600 mg 4 times daily (n = 101); or placebo IR, 4 times daily (n = 103), for 12 weeks. The primary efficacy variable was change from baseline in morning trough forced expiratory volume in 1 second (FEV1).
Results: Improvement in trough FEV1 was observed after 2 weeks of treatment (P = .001) and was maintained throughout the study. After 12 weeks of dosing, FEV1 improved by a mean of 0.39 L (20.8%) in the zileuton CR group vs 0.27 L (12.7%) in the placebo CR group (P = .02). A significant decline in beta-agonist use and a smaller proportion of patients reporting asthma exacerbations were observed in the zileuton CR group vs the placebo CR group. Adverse event profiles were similar across treatment groups. Elevations in alanine aminotransferase levels at least 3 times the upper limit of normal that reversed after drug withdrawal were seen in 5 zileuton CR-treated patients (2.5%) vs 1 placebo CR-treated patient (0.5%).
Conclusions: Treatment with zileuton CR, 1,200 mg twice daily, resulted in a significant improvement in asthma control, and the safety and efficacy profile was similar to that observed with zileuton IR, 600 mg 4 times daily (Zyflo).