Background A substantial number of patients have symptomatic asthma despite treatment according to guidelines. Several studies have confirmed that tiotropium Respimat®, a once-daily long-acting anticholinergic bronchodilator, improves lung function in symptomatic patients receiving at least medium-dose inhaled corticosteroids (ICS) + long-acting β2-agonist (LABA) (Kerstjens et al. NEJM 2012;367:1198–207; Bateman et al. JACI 2011;128:315–22). Here we examine whether the atopic and/or allergic status of patients in these trials influenced their response to tiotropium Respimat®.
Method Two 48-week trials of tiotropium Respimat® 5 µg (PrimoTinA-asthma®: NCT00776984, NCT00772538) in patients (n = 912) on high-dose ICS + LABA; two 24-week trials of tiotropium Respimat® 5 µg and 2.5 µg (MezzoTinA-asthma®: NCT01172808, NCT01172821) in patients (n = 2100) on moderate-dose ICS. Pre-planned analyses (pooled populations) were performed in two subgroups defined at baseline as total serum immunoglobulin E (IgE) ≤ or >430 μg/L or blood eosinophils ≤ or >0.6×109/L or clinical judgement of allergic status (‘No’ or ‘Yes’). All tiotropium doses were delivered via the Respimat® SoftMist™ inhaler.
Results Tiotropium Respimat® 5 µg or 2.5 µg improved peak and trough forced expiratory volume in 1 second versus placebo (Table) independent of IgE, eosinophil count and clinical judgement.
Conclusion Once-daily tiotropium Respimat® as add-on to ICS or ICS + LABA in patients with moderate to severe symptomatic asthma reduces airflow obstruction, apparently independent of their atopic and/or allergic status.