Background and objectives: To compare the efficacy and safety of tiotropium inhaled via Respimat Soft Mist Inhaler, a multidose propellant-free inhaler and HandiHaler, a single-dose dry powder inhaler, in a phase 2 study of Japanese COPD patients.
Methods: Patients with FEV(1)<or=70% predicted, FEV(1)/FVC<or=70% and a smoking history of >10 pack-years received tiotropium once daily via Respimat (5microg) and HandiHaler (18microg) for 4 weeks each in a randomised, double-blind, double-dummy, two-way crossover study. Lung function, adverse events, pharmacokinetics and safety were assessed.
Results: Of 184 patients screened, 134 were evaluable. The trough FEV(1) response on Day 29 showed Respimat to be non-inferior to HandiHaler (mean treatment difference, 0.008L; 95% CI, -0.009 to +0.024L; p<0.001). Peak and average FEV(1) and FVC responses on Day 1 and Day 29 were very similar for the two treatments. Tiotropium plasma levels and excretion kinetics showed a similar profile of systemic exposure for the two formulations of tiotropium. Adverse events were reported by similar numbers of patients on each treatment, i.e. 27.9 and 30.6% in the Respimat and HandiHaler groups, respectively.
Conclusions: In Japanese patients with COPD, tiotropium Respimat 5microg and tiotropium HandiHaler 18microg showed a similar profile of efficacy, safety and pharmacokinetics.