Effect of Indacaterol on Dynamic Lung Hyperinflation and Breathlessness in Hyperinflated Patients with COPD

Abstract: Indacaterol is a novel, inhaled once-daily ultra long-acting β₂-agonist for the treatment of COPD. This randomised, double-blind, placebo-controlled, two-period crossover study evaluated the effect of two-week treatment with indacaterol 300 μg on peak and isotime exercise inspiratory capacity (IC) in patients with COPD. Patients (40–80 years) with post-bronchodilator forced expiratory volume in 1 s (FEV₁)/forced vital capacity (FVC) <70%, percent predicted FEV₁ ≥40% and ≤80%, smoking history ≥20 pack-years and functional residual capacity >120% of predicted normal were randomised to receive indacaterol 300 μg or placebo once-daily via a single-dose dry powder inhaler. Following 14 days of treatment, IC at peak and isotime during constant-load (80% of maximum workload) cycle ergometry was analysed using linear mixed-effects models. Safety and tolerability were also monitored. Twenty-seven patients (67% male; mean age, 61.3 years) were randomised; 24 completed the study. On Day 14, indacaterol showed statistically significant improvements over placebo in peak (317 mL [95% CI: 118–517]; p < 0.01) and isotime IC (268 mL [95% CI: 104–432]; p < 0.01). Statistically significant improvements were observed with indacaterol versus placebo on Day 14 for the following secondary endpoints: resting IC, trough FEV₁, dyspnoea (BDI/TDI and Borg CR10 scale at isotime) and exercise endurance time. Indacaterol was well tolerated, with no serious adverse events or deaths. In conclusion, indacaterol 300 μg administered once-daily showed a clinically relevant increase in IC after 14 days of treatment, reflecting a reduction in dynamic hyperinflation.