Efficacy of once-daily tiotropium Respimat in adults with asthma at GINA Steps 2-5.

Tiotropium Respimat is an efficacious add-on to maintenance treatment in patients with symptomatic asthma. Currently, the Global Initiative for Asthma (GINA) strategy recommends tiotropium for patients at Steps 4-5. To assess the clinical benefits of tiotropium Respimat across asthma severities, GINA Steps 2-5, a post hoc analysis of five double-blind trials (12-48-weeks; patients aged 18-75 years) investigated the effect of tiotropium Respimat, 5 µg or 2.5 µg, versus placebo, on peak forced expiratory volume in 1 s (FEV1) within 3 h post-dose (FEV1(0-3h)) response, and Asthma Control Questionnaire-7 (ACQ-7) responder rate. GINA step grouping was based on patients' background treatment regimen. Baseline characteristics of patients (N = 2926) were balanced between treatments. Tiotropium Respimat showed consistent improvements in lung function across GINA steps; placebo-corrected peak FEV1(0-3h) improvements after tiotropium Respimat 5 µg and 2.5 µg were: Step 2 (Week 8), 135 mL (95% confidence interval: 84, 187) and 155 mL (103, 206); Step 3 (Week 24), 187 mL (139, 235) and 235 mL (187, 283); Step 4 (Week 24), 111 mL (63, 159) and 181 mL (35, 326); Step 5 (Week 24; 5 µg only), 164 mL (5, 323). Asthma control improved with tiotropium Respimat versus placebo, showing statistical significance (nominal P value) with tiotropium Respimat 5 µg at Step 4 (odds ratio 1.36 [1.03, 1.78]). Safety profiles were similar between treatments. In conclusion, tiotropium Respimat add-on therapy improves lung function, and may improve asthma control, in adults across disease severities.