Severe Asthma and Biological Therapy: When, Which, and for Whom.

Asthma is a heterogeneous chronic inflammatory disease of the airways that affects approximately 300 million people worldwide. About 5-10% of all asthmatics suffer from severe or uncontrolled asthma, associated with increased mortality and hospitalization, reduced quality of life, and increased health care costs. In recent years, new treatments have become available, and different asthma phenotypes characterized by specific biomarkers have been identified. Biological drugs are currently indicated for patients with severe asthma that is not controlled with recommended treatments. They are mostly directed against inflammatory molecules of the type 2 inflammatory pathway and are effective at reducing exacerbations, maintaining control over asthma symptoms, and reducing systemic steroid use, which is associated with well-known adverse events. Although biological drugs for severe asthma have had a major impact on the management of the disease, there is still a need for head-to-head comparison studies of biologics and to identify new biomarkers for asthma diagnosis, prognosis, and response to treatment. Identifying novel biomarkers could facilitate the development of therapeutic strategies that are precisely tailored to each patient's requirements.