Tiotropium: a new therapeutic option in asthma

Although bronchial hyperresponsiveness to cholinergic agents is a main feature of asthma, the role of anticholinergic drugs in chronic asthma management has been largely underestimated. Several single-dose studies comparing acute bronchodilation induced by ipratropium bromide with salbutamol have shown that salbutamol is more effective than ipratropium in treating asthma. Recently, tiotropium has been studied in asthma, when added to low-medium dose inhaled corticosteroids (ICS) in unselected moderate asthmatics or in patients with uncontrolled asthma, or with COPD and history of asthma. Later, studies on patients with Arg/Arg beta2-receptor polymorphism demonstrated a similar efficacy of tiotropium in comparison with salmeterol, when both were added to ICS. More recently, pivotal long-term studies have been performed on severe asthmatics uncontrolled under ICS/LABA combination, showing the efficacy of tiotropium in improving lung function and in increasing the time until the first severe asthma exacerbation. These data support the use of tiotropium on top of ICS/LABA combination in moderate-severe asthmatic patients. New studies are going to be published on the use of tiotropium in mild and moderate asthmatics, when added to low or medium dose ICS, in comparison with ICS alone or with ICS/LABA combination. These data might extend the indication for using tiotropium in asthma. Therefore, tiotropium represents now a valid therapeutic option, in addition to the current therapy available for severe asthmatics, and in alternative to LABA in selected asthma populations. The specific asthma phenotype which may be appropriate for tiotropium treatment should still be defined.