The soft-mist inhaler is licensed for use in patients currently treated with inhaled corticosteroids (at least 800 microgram daily of budesonide or equivalent) and long-acting β2 agonists (LABAs) who have experienced one or more severe exacerbations in the previous year.
It is already licensed for maintenance bronchodilator treatment in patients with chronic obstructive pulmonary disease. The dose for both conditions is 5 microgram once daily, taken as two consecutive 2.5 microgram puffs.
Tiotropium is a long-acting muscarinic antagonist (LAMA or anticholinergic) that blocks muscarinic acetylcholine receptors on bronchial smooth muscle, leading to bronchodilation.
Two randomised, double-blind, placebo-controlled trials of identical design evaluated the safety and efficacy of tiotropium soft-mist inhaler (5 microgram once daily) added to high-dose inhaled corticosteroids and LABAs in patients with poorly controlled asthma, defined as persistent airflow obstruction and at least one severe exacerbation requiring systemic corticosteroid treatment in the previous year.
After a four-week screening period, 912 patients entered the 48-week treatment phase and 907 were included in the analysis.
At 24 weeks, peak FEV1 showed a greater increase from baseline in the tiotropium group than in the placebo group, with mean differences of 86ml (p=0.01) and 154ml (p<0.001) in the two trials, respectively. The corresponding differences in trough FEV1 were 88ml (p=0.01) and 111ml (p<0.001), respectively.
Analysis of pooled 48-week data showed that patients in the tiotropium group had a time to first severe exacerbation (necessitating initiation or doubling of systemic corticosteroids for ≥3 days) of 282 days compared with 226 days for those in the placebo group, translating into a 21% reduction in the relative risk of severe exacerbation (hazard ratio 0.79; 95% confidence interval [CI] 0.62–1.00, p=0.03).
The overall incidence of adverse events was similar in the tiotropium and placebo groups (73.5% and 80.3%, respectively).
Updated prescribing information for Spiriva Respimat will appear in the December print edition of MIMS.
Further information: Boehringer Ingelheim