ABSTRACT: Indacaterol is a novel once-daily ultra long-acting ?2-agonist for the treatment of chronic obstructive pulmonary disease. It is known that ?2-agonists, like other adrenergic compounds, can prolong the QT-interval. This thorough QT/QTc study (as per ICH E14 guideline) evaluated the effect of indacaterol on the QT interval in healthy subjects.In this randomized, double-blind, parallel-group, placebo- and positive-controlled (open-label moxifloxacin) study, non-smoking healthy subjects (18-55 years, body mass index: 18.5-32.0 kg/m2) were randomized (4:4:2:4:1) to 14-day treatment with once-daily indacaterol (150 ?g, 300 ?g, or 600 ?g), placebo, or placebo/moxifloxacin (double-blind 14-day treatment with placebo and a single open-label dose of 400 mg moxifloxacin on Day 14). The primary endpoint was the change from baseline on Day 14 in QTcF (QT interval corrected for heart rate using Fridericia's formula).In total, 404 subjects were randomized to receive indacaterol (150 [n = 108], 300 [n = 108], 600 ?g [n = 54]), placebo (n = 107), or placebo/moxifloxacin (n = 27); 388 subjects completed the study. Maximal time-matched mean (90% confidence intervals) treatment differences from placebo in QTcF change from baseline on Day 14 were 2.66 (0.55, 4.77), 2.98 (1.02, 4.93) and 3.34 (0.86, 5.82) ms for indacaterol 150 ?g, 300 ?g and 600 ?g, respectively. Study sensitivity was confirmed with moxifloxacin demonstrating a significant maximal time-matched QTcF prolongation of 13.90 (10.58, 17.22) ms compared to placebo. All indacaterol doses were well tolerated.Indacaterol, at doses up to 600 ?g once daily (2-4 times the therapeutic dose) does not have any clinically relevant effect on the QT interval.