Bronchodilator effects of indacaterol and formoterol in patients with COPD

BackgroundResting inspiratory capacity (IC) reflects static hyperinflation in chronic obstructive pulmonary disease (COPD). This study compared the effects of formoterol and indacaterol, a novel once-daily ultra-long-acting β2-agonist (or ultra-LABA), on resting IC and forced expiratory volume in 1 s (FEV1).MethodsThirty patients with COPD (mean FEV1/FVC 0.49, mean FEV1 56% predicted) each inhaled three treatments (two in randomized sequence followed by open-label formoterol) on separate study days: a single dose of indacaterol 300 μg, matching placebo, and two doses of formoterol 12 μg 12 h apart.ResultsIndacaterol and formoterol increased FEV1 and IC at all time points relative to placebo (p < 0.001). Peak effects on FEV1 were similar, while indacaterol had a greater effect on peak IC (31% vs 23% from pre-dose; p = 0.034). Indacaterol had a greater effect than formoterol on FEV1 at 8 h (1.47 vs 1.39 L; p = 0.014) and 24 h (1.44 vs 1.35 L; p = 0.003), and on IC from 4 to 24 h (differences of 0.13–0.19 L; p < 0.05). At 24 h, indacaterol and formoterol increased FEV1 by 17.7% and 7.5%, respectively, from pre-dose.ConclusionsThis study discriminated between the effects on IC and FEV1 of once daily indacaterol and twice daily formoterol. The greater effect of indacaterol on IC may translate into improved long-term clinical outcomes.