Indacaterol 75 μg once daily is a long-acting β 2 agonist approved for maintenance bronchodilator treatment in patients with chronic obstructive pulmonary disease (COPD). The purpose of this study was to evaluate patients’ perception of onset of effect with a single dose.
In this double-blind, crossover, Phase IV study, 40 patients were randomized to receive a single dose of indacaterol 75 μg or placebo via a dry powder inhaler device. The primary variable was time until patient’s perception of onset of effect, using a simple self-administered (nonvalidated) questionnaire that patients answered at nine protocol-specified time points. Exploratory variables included change in forced expiratory volume in 1 second (FEV 1) and change in percent predicted FEV 1 from predose to postdose (determined 60–75 minutes postdose).
The least-squares mean time to patient’s perception of onset of effect was 25.4 minutes and 23.9 minutes for indacaterol and placebo, respectively. There was no significant effect for treatment, period, or sequence on the time to patient’s perception. In addition, no statistically significant differences between treatments were observed for patient’s global satisfaction with onset of effect and global expectation of treatment adherence. For the exploratory variable change in FEV 1 from predose to postdose, indacaterol showed superiority over placebo with a clinically relevant least-squares mean treatment difference of 0.12 L ( P<0.0001). There was little or no association between patient’s perception of time to onset of effect and change in FEV 1, or change in percent predicted FEV 1. Both treatments were well tolerated.
A single dose of indacaterol 75 μg did not separate from placebo in terms of patient perception of onset, although there was an improvement in FEV 1 for indacaterol compared with placebo. Development and use of a validated questionnaire may be needed to address the inconsistency in evaluating this patient-related outcome.