Bronchodilator effects of indacaterol and formoterol in patients with COPD.

BACKGROUND

Resting 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 beta(2)-agonist (or ultra-LABA), on resting IC and forced expiratory volume in 1 s (FEV(1)).

METHODS

Thirty patients with COPD (mean FEV(1)/FVC 0.49, mean FEV(1) 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 microg, matching placebo, and two doses of formoterol 12 microg 12 h apart.

RESULTS

Indacaterol and formoterol increased FEV(1) and IC at all time points relative to placebo (p<0.001). Peak effects on FEV(1) 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 FEV(1) 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 FEV(1) by 17.7% and 7.5%, respectively, from pre-dose.

CONCLUSIONS

This study discriminated between the effects on IC and FEV(1) of once daily indacaterol and twice daily formoterol. The greater effect of indacaterol on IC may translate into improved long-term clinical outcomes.