Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of Single and Repeat Inhaled Doses of Umeclidinium in Healthy Subjects: Two Randomized Studies

Background Chronic obstructive pulmonary disease (COPD) has a significant negative impact on quality of life and increases the risk of premature death. Umeclidinium is a long-acting muscarinic receptor antagonist in development for the treatment of COPD with the aim to broaden treatment options for clinicians and patients by providing improved symptom control. Objective To characterize the safety, tolerability, pharmacokinetics and pharmacodynamics of single and repeat inhaled doses of umeclidinium in healthy subjects. Study Design Two randomized, placebo-controlled, ascending-dose studies were conducted in healthy ipratropium bromide-responsive subjects. In the single-dose study, subjects (n = 20) received umeclidinium (10-350 mu g), tiotropium bromide 18 mu g and placebo in a crossover dosing schedule. In this study, lung function was assessed for 24 h by measuring specific airways conductance (sGaw) and forced expiratory volume in 1 s (FEV1). In the repeat-dose study, subjects (n = 36) received umeclidinium (250-1,000 mu g) and placebo for 14 days in a parallel-group schedule. Results Adverse events (AEs) were reported in five subjects (single-dose study) and 23 subjects (repeat-dose study); none were serious. In both studies, no abnormalities in 12-lead electrocardiogram parameters, 24-h Holter monitoring or lead II monitoring were reported as AEs. Umeclidinium was rapidly absorbed following single-dose administration [time to reach the maximum plasma concentration (t(max)) 5-15 min] and repeat-dose administration (t(max) 5-7 min). Following repeat dosing, the geometric mean plasma elimination half-life was approximately 27 h and statistically significant accumulation was observed for the area under the plasma concentration-time curve, maximum plasma concentration and cumulative amount of unchanged drug excreted into the urine at 24 h (range 1.5- to 4.5-fold). Umeclidinium at doses of 100 mu g and above, and tiotropium bromide demonstrated statistically significant bronchodilatory effects relative to placebo at 12 h post-dosing, which lasted up to 24 h for umeclidinium 350 mu g and for tiotropium bromide. Relative to placebo, these increases in sGaw were 24-34 % at 12 h post-dose and 13 % at 24 h post-dose. Increases in FEV1 achieved statistical significance at 12 and 24 h for umeclidinium 100 mu g and 350 mu g compared with placebo. Conclusion Umeclidinium was well tolerated and demonstrated bronchodilatory effects in healthy subjects for up to 24 h. These bronchodilatory effects can be potentially clinically important in patients with airway obstruction such as COPD. The data obtained have informed dose selection for subsequent trials in subjects with COPD.