Bronchodilator efficacy of 18 μg once-daily tiotropium inhalation via Discair(®) versus HandiHaler(®) in adults with chronic obstructive pulmonary disease: randomized, active-controlled, parallel-group, open-label, Phase IV trial

PURPOSE: To compare the bronchodilator efficacy of 18 μg once-daily tiotropium inhalation administered via Discair(®) versus HandiHaler(®) in adults with moderate-to-severe chronic obstructive pulmonary disease (COPD). PATIENTS AND METHODS: Fifty-eight patients with moderate-to-severe COPD were enrolled in this randomized, active-controlled, parallel-group, open-label, Phase IV non-inferiority trial. Patients were randomly assigned to a test group (n=29, inhalation with Discair) or a reference group (n=29, inhalation with HandiHaler). The primary efficacy parameter was the average maximum change in forced expiratory volume in 1 second (FEV(1), in L). Change in forced vital capacity (FVC, in L), %FEV(1) and %FVC, the standardized area under the response–time curve (AUC) for the absolute change in FEV(1) and FVC, time to onset and peak of response, and safety data were also evaluated. RESULTS: The test inhaler was non-inferior to the reference inhaler in terms of maximum change in FEV(1) at 24 h (unadjusted change: 0.0017 L [95% confidence interval [CI]: −0.0777, 0.0812]; change adjusted for time to reach maximum change in FEV(1) and smoking in pack-years: 0.0116 L [95% CI: −0.0699, 0.0931]), based on a non-inferiority margin of 0.100 L. There were also no significant differences between the two groups in maximum change in FVC value from baseline (0.3417 L vs 0.4438 L, P=0.113), percent change from baseline (22.235 vs 20.783 for FEV(1), P=0.662; 16.719 vs 20.337 for FVC, P=0.257), and AUC(0–24 h) (2.949 vs 2.833 L for FEV(1), P=0.891; 2.897 vs 4.729 L for FVC, P=0.178). There were no adverse events, serious adverse events, or deaths. CONCLUSION: Our findings show that the Discair was non-inferior to the HandiHaler. More specifically, these devices had similar clinical efficacy in terms of time-dependent response over 24 h for patients with moderate-to-severe COPD.