Efficacy of indacaterol 75 μg once-daily on dyspnea and health status: results of two double-blind, placebo-controlled 12-week studies.

Indacaterol is an inhaled, once-daily, long-acting ®(2)-agonist for the treatment of COPD. Most previous studies were conducted with doses of 150 and/or 300 μg once-daily, and data with the 75 μg dose are limited. Two identically designed studies were, therefore, conducted to evaluate the efficacy and safety of the 75 μg once-daily dose. In two double-blind studies conducted in the USA, patients with moderate-to-severe COPD were randomized to treatment with indacaterol 75 μg once-daily (n = 163 and 159) or matching placebo (n = 160 and 159) for 12 weeks. The primary variable was forced expiratory volume in 1 s measured 24 h post-dose after 12 weeks (reported elsewhere). This report describes secondary efficacy endpoints, including transition dyspnea index (TDI) and St George's Respiratory Questionnaire (SGRQ) total scores, and the percentages of patients with improvements of or above the minimal clinically important difference (MCID; ≥1 in TDI score and ≥4 in SGRQ score). Differences between indacaterol and placebo for TDI total score at week 12 were 1.23 (p < 0.001) and 0.45 (p = 0.16), with odds ratios for achieving the MCID of 2.19 (p = 0.002) and 1.58 (p = 0.065). SGRQ total score decreased (improved) from baseline by 5.8 and 4.9 units with indacaterol at week 12 (2.0 and 0.9 with placebo), with odds ratios for achieving the MCID of 1.80 (p = 0.024) and 1.71 (p = 0.031). Patients receiving indacaterol had statistically significant or numerical improvements in diary-derived symptom variables compared with placebo. Treatment with indacaterol 75 μg may provide useful improvements in patient-reported outcomes in patients with moderate-to-severe COPD.