Effect of an additional dose of indacaterol in COPD patients under regular treatment with indacaterol

In this randomized, double-blind, crossover study, we explored the acute effects on respiratory function and safety of an additional dose of indacaterol 150 μg in stable COPD patients regularly treated with a conventional dose of indacaterol 150 μg.

On two non-consecutive days, patients inhaled indacaterol 150 μg. After 180 min, they inhaled an additional dose of indacaterol 150 μg or placebo. Lung function, oxygen saturation by pulse oximetry (SpO(2)) and heart rate were measured before the first drug administration and up to 360 min thereafter.

In both treatment groups, indacaterol induced a significant (P < 0.05) bronchodilation during all the study time. The difference between the FEV(1) AUCs(0-180 min) was not statistically significant (P = 0.971). On the contrary, the difference between the FEV(1) AUCs(180-360 min) was significant (P < 0.0001). However, only 8 out of 20 patients showed a further increase of at least 100 ml from the peak obtained after the first administration of indacaterol 150 μg with the second dose of 150 μg. Indacaterol 150 μg induced a modest but significant decrease in SpO(2) up to 60 min and a second dose of indacaterol 150 μg significantly decreased the SpO(2) mean value up to 360 min.

This study suggests that it is reasonable and safe to increase the dose of indacaterol in those stable COPD patients who are under regular therapy with indacaterol 150 μg from which they do not draw the maximum benefit because they are unable to perceive bronchodilation. However, only a minority of patients seem to benefit from this dose escalation, at least in terms of spirometric improvement.