Background: Tiotropium, a once daily inhaled anticholinergic delivered via HandiHaler, provides bronchodilation for >24h and improves patient-centred outcomes. The Respimat Soft Mist Inhaler (SMI), a novel, propellant-free inhaler, has been developed and proposed as an alternative delivery device for use with tiotropium.
Methods: In a pre-specified, pooled analysis of two 30-week, double-blind, double-dummy, crossover studies, 207 patients with Chronic Obstructive Pulmonary Disease (COPD) were randomised to receive once daily tiotropium 5 microg or 10 microg (aqueous solution delivered via Respimat SMI), tiotropium 18 microg (inhalation powder via HandiHaler) or placebo. The primary endpoint was trough forced expiratory volume in 1s (FEV(1)) response. Forced vital capacity (FVC), peak expiratory flow rate (PEFR), rescue medication use, safety and pharmacokinetics (in a subgroup of patients) were also assessed.
Results: Both tiotropium doses delivered by Respimat SMI were significantly superior to placebo and non-inferior to tiotropium 18 microg HandiHaler on the primary endpoint (all p<0.0001). All active treatments were significantly superior to placebo (all p<0.0001) and both doses of tiotropium Respimat SMI were non-inferior to tiotropium 18 microg HandiHaler on the secondary spirometry variables and rescue medication use. The systemic exposure was similar between tiotropium 5 microg Respimat SMI and tiotropium 18 microg HandiHaler but was higher for tiotropium 10 microg Respimat SMI. All active treatments were well tolerated.
Conclusions: Tiotropium 5 microg Respimat SMI is comparable with tiotropium 18 microg HandiHaler in terms of efficacy, pharmacokinetics and safety. Respimat SMI is an effective alternative, multi-dose delivery device for tiotropium.