Introduction and Objectives Aclidinium bromide, a second-generation, long-acting muscarinic antagonist with low systemic activity, is in clinical development for the twice daily maintenance treatment of chronic obstructive pulmonary disease (COPD). This Phase IIb study investigated the dose-response bronchodilation of aclidinium twice daily vs placebo and an active control (formoterol 12 μg twice daily) in patients with moderate to severe COPD.

Methods In this double-blind, double-dummy, cross-over study, 79 patients received 7-day treatments of aclidinium 100 μg, 200 μg and 400 μg, formoterol 12 μg and placebo twice daily over five treatment periods separated by a 7-day washout. The primary endpoint was change from baseline in normalised forced expiratory volume in 1 second (FEV₁) area under the curve (AUC)_0–12 at Day 7. Other efficacy assessments included change from baseline at Day 7 in normalised FEV₁ AUC_0–24 and morning pre-dose (trough) and peak FEV₁. Adverse events (AEs) were reported throughout the study.

Results Aclidinium provided dose-dependent bronchodilation compared with placebo as assessed by change from baseline in normalised FEV₁ AUC_0–12 and FEV₁ AUC_0–24 at Day 7 (Abstract P256 table 1). The bronchodilation provided by aclidinium 400 μg during the first 12 h was comparable to the active control, formoterol 12 μg. Aclidinium improved morning pre-dose trough FEV₁ and peak FEV₁ after 7 days compared with placebo; the 400 μg dose was most comparable to formoterol 12 μg. Aclidinium was well tolerated; the safety profile of all doses was comparable to that of placebo.

Conclusion A dose-dependent bronchodilation was observed with aclidinium twice daily. The bronchodilation provided by the highest dose of aclidinium (400 μg) twice daily was comparable to formoterol 12 μg twice daily. The safety profile of aclidinium was similar to placebo, with no dose-dependent AEs observed.