The Effect of Tiotropium in Symptomatic Asthma Despite Low- to Medium-Dose Inhaled Corticosteroids: A Randomized Controlled Trial

Abstract

Background: Tiotropium, a once-daily long-acting anticholinergic bronchodilator, has demonstrated efficacy in patients with asthma who were symptomatic despite treatment with medium- to high-dose inhaled corticosteroids (ICS). Objective: The objective of this study was to evaluate the efficacy and safety of once-daily tiotropium Respimat (5 μg or 2.5 μg), compared with placebo Respimat, as add-on therapy to low- to medium-dose ICS for adults with symptomatic asthma. Methods: A phase III, double-blind, placebo-controlled trial was conducted (NCT01316380). Adults with symptomatic asthma receiving low- to medium-dose ICS (200-400 μg budesonide or equivalent dose) and a pre-bronchodilator forced expiratory volume in 1 second (FEV1) ≥60% and ≤90% of predicted normal were randomized to 12 weeks of treatment with once-daily tiotropium Respimat 5 μg or 2.5 μg, or placebo Respimat, as add-on therapy to ICS. The primary endpoint was peak FEV1(0-3h) response. Results: In total, 464 patients were randomized (61% female; mean age 43 years; mean baseline FEV1 78% of predicted normal). After 12 weeks, both tiotropium Respimat doses were superior to placebo (adjusted mean difference from placebo: 5 μg, 128 mL; 2.5 μg, 159 mL; both P