Development of New Therapies for Severe Asthma.
Persistent asthma has long been treated with inhaled corticosteroids (CSs), as the mainstay of therapy. However, their efficacy in patients with more severe disease is limited, which led to the incorporation of poor response to ICSs (and thereby use of high doses of ICS) into recent definitions of severe asthma. Several studies have suggested that severe asthma might consist of several different phenotypes, each with ongoing symptoms and health care utilization, despite the use of high doses of ICS, usually in combination with a second or third controller. Several new therapies have been approved for severe asthma. Long-acting muscarinic agents have recently been approved as an additional controller agent and appear to improve lung function, although their effect on symptoms and exacerbations is less. Although bronchial thermoplasty (BT) has emerged as a therapy for severe asthma, little is understood regarding the appropriate selection of these patients. Considerable data have emerged to support the presence of a group of patients with severe asthma who have ongoing Type 2 inflammation. These patients appear to respond to targeted biologic approaches which are at the current time mostly investigational. In contrast, few effective therapies for patients with less or no evidence for Type 2 inflammation have emerged. Many new and exciting therapies are at the forefront for severe asthma therapy and, in conjunction with precision medicine approaches to identify the group of patients likely to respond to these approaches, will change the way we think about treating severe asthma.