Managing Severe Asthma: A Role for the Long-Acting Muscarinic Antagonist Tiotropium

Severe asthma is associated with substantial morbidity and mortality. Therapies must be maximized to gain control of a patient's severe asthma; however, avoiding overtreatment is also important. The mainstays of asthma maintenance treatment are inhaled corticosteroids (ICS) and long-acting β ₂-agonsits (LABAs), with the option of supplementary add-on treatments. New add-on treatments for severe asthma have emerged over the past two decades, including personalized biological therapies that are guided by a patient's asthma phenotype. In addition, the long-acting muscarinic antagonist tiotropium has been recommended as an add-on treatment for severe asthma. Phase III clinical trials have shown tiotropium in combination with ICS/LABA to be efficacious in patients with severe asthma. Further analyses of clinical trial data have indicated that there is no benefit in stratifying patients by phenotype to predict tiotropium efficacy. Furthermore, health economic studies suggest tiotropium to be a cost-effective treatment in patients with severe asthma. This review will present the evidence surrounding the role of tiotropium in severe asthma and will discuss the use of tiotropium add-on therapy before personalized medicine strategies in the stepwise process of gaining asthma control.