24-hour bronchodilator efficacy of single doses of indacaterol in patients with persistent asthma: comparison with placebo and formoterol

Objective: To assess the 24-h bronchodilator efficacy and safety of single-dose indacaterol in asthma. Methods: This was a five-period, double-blind, double- dummy, crossover study in patients with persistent asthma. On separate study days, patients inhaled a single dose of indacaterol (150, 300 or 600 mg) in the morning via a single-dose dry powder inhaler (SDDPI), formoterol 12 mg twice daily via its proprietary SDDPI, or placebo. Study days were separated by a washout period of at least 6 days. Results: Of the 45 patients randomized to treatment, 42 completed the study. The 24-h trough FEV(1) (primary endpoint) was significantly higher than placebo following all doses of indacaterol (mean [95% CI] differences of 0.11 [0.06, 0.16], 0.21 [0.17, 0.26] and 0.22 [0.18, 0.27] L for 150, 300, and 600 mu g, respectively) and formoterol (by 0.13 [0.08, 0.18] L). The 24-h trough FEV(1) was significantly higher following indacaterol 300 and 600 mg than indacaterol 150 mg (by 0.11 [0.06, 0.15] and 0.12 [0.07, 0.17] L, respectively) or formoterol (by 0.08 [0.03, 0.13] L vs. 300 mg; by 0.09 [0.04, 0.14] L vs. 600 mg). Most adverse events were mild-to-moderate and transient. Examination of serum potassium, blood glucose, QTc interval, pulse rate, and blood pressure raised no concern over the safety of indacaterol. Conclusions: Single doses of indacaterol provided effective 24-h bronchodilation and were well tolerated in patients with persistent asthma. Safety findings were limited by non-standardized diet conditions in this study but suggest a minimal systemic treatment effect.