Tiotropium respimat: Comparison of bronchodilator efficacy of 5 and 2.5 µg doses

Background: Safety and efficacy of tiotropium Respimat 5 µg (R5) and 2.5 µg (R2.5) doses were compared with tiotropium HandiHaler 18 μg (HH) in two recent chronic obstructive pulmonary disease (COPD) trials. Aims and objectives: To compare bronchodilator efficacy of once-daily R5 and R2.5 and HH in TIOtropium Safety and Performance In Respimat (TIOSPIR; [NCT01126437][1])1 and the 205.458 ([NCT01222533][2])2 trials. Methods: TIOSPIR: Randomized, double-blind (n=17,135; mean 2.3 years' follow up) trial assessing mortality and exacerbations. Included a spirometry substudy (n=1370), predefined test of noninferiority of R5 and R2.5 vs HH for trough forced expiratory volume in 1 second (FEV1), average 24-120 weeks (noninferiority margin 50 mL). 205.458: Multicentre, placebo-controlled, randomized within Respimat (1.25, 2.5, 5 µg), five-way crossover trial with 4-week treatment periods (n=154). Results: TIOSPIR: Adjusted mean trough FEV1 (average 24-120 weeks) was 1.285L for R5 and 1.295 L for HH (difference vs HH, -10 mL; 95% confidence interval [CI], -38 to 18 mL), and 1.258 L for R2.5 (difference vs HH, -37 mL; 95% CI, -65 to -9 mL). 205.458: R2.5, R5 and HH showed significant improvements in trough FEV1 versus placebo. Mean trough FEV1 for R5 was comparable to HH but was 27 and 41 mL lower than HH for R2.5 and R1.25, respectively. Conclusion: In TIOSPIR, R5 was noninferior to HH for FEV1, but R2.5 was inferior to HH. Similar results were seen in the 205.458 trial and support the use of tiotropium Respimat 5μg once daily for the maintenance treatment of COPD. TIOSPIR and 205.458 trials were funded by Boehringer Ingelheim. [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT01126437&atom=%2Ferj%2F44%2FSuppl_58%2FP924.atom [2]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT01222533&atom=%2Ferj%2F44%2FSuppl_58%2FP924.atom