Results from a recent study published in the journal Respiratory Medicine showed that treatment with the bronchodilator tiotropium Respima can improve lung function in patients with asthma.

International and national guidelines for the management of asthma recommend inhaled corticosteroids (ICS) as the first step for maintenance treatment of patients with symptomatic asthma. Increasing the ICS dose or adding a long-acting β₂-agonist (LABA), leukotriene modifier or sustained-release theophylline to low-dose ICS are options for patients who subsequently remain or become symptomatic. However, despite these options, at least 40% of patients with asthma remain symptomatic on currently available maintenance therapies.

In Phase II trials, tiotropium solution for inhalation delivered via the Respimat^® SoftMist™ inhaler (Boehringer Ingelheim, Ingelheim am Rhein, Germany) provided improvements in lung function at once-daily doses of 10 μg, 5 μg, 2.5 μg or 1.25 μg when compared with placebo Respimat.^®

In order to examine if a regimen dosing of tiotropium (once per day twice per day) via the Respimat SoftMist inhaler had an effect in the efficacy and safety of a 24-hour bronchodilator versus placebo Respimat in patients with asthma, in their study entitled “Once-daily tiotropium Respimat^® 5 μg is an efficacious 24-h bronchodilator in adults with symptomatic asthma,” Roland Buhl from the Universitätsmedizin der Johannes Gutenberg-Universität Mainz in Germany and colleagues randomized a total of 94 patients in a placebo-controlled cross over study with 4-week treatment periods of tiotropium 5 μg (once-daily, evening) and 2.5 μg (twice-daily, morning and evening).

The clinical trial’s main outcome for efficacy was the forced expiratory volume in 1 second (FEV₁) area under the curve from 0 to 24 h (AUC)_(0–24h) at the end of each treatment period. The team of researchers also examined the included peak forced expiratory volume in 1 second measured within 24 hours of the last evening inhalation (peak FEV_1(0–24h)), trough FEV₁ measured prior to evening dosing, morning and evening peak expiratory flow (PEF_am and PEF_pm) and pharmacokinetic assessments.

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Results revealed that after 24 hours in both tiotropium dosing regimens, the bronchodilation was similar. FEV₁ AUC_(0–24h) response was larger with both tiotropium dosing regimens (5 μg once per day: 158 ± 24 mL; 2.5 μg twice per day; 149 ± 24 mL) in comparison to the placebo.

The researchers observed an Improvement in peak FEV_1(0–24h), trough FEV₁and pre-dose PEF_am/pm in both the regimen dosing groups versus the placebo.

Based on the results, the researchers indicate in their study that improvements in lung function with tiotropium Respimat^® add-on to medium-dose ICS were similar for 5 μg once per day and twice per day 2.5 μg, which supports tiotropium Respimat^® 5 μg as a once per day bronchodilator that is effective over a 24-h dosing interval in patients with asthma.