Severe refractory asthma: current treatment options and ongoing research

Abstract

Patients with severe asthma have a greater risk of asthma-related symptoms, morbidities, and exacerbations. Moreover, healthcare costs of patients with severe refractory asthma are at least 80% higher than those with stable asthma, mainly because of a higher use of healthcare resources and chronic side effects of oral corticosteroids (OCS). The advent of new promising biologicals provides a unique therapeutic option that could achieve asthma control without OCS. However, the increasing number of available molecules poses a new challenge: the identification and selection of the most appropriate treatment. Thanks to a better understanding of the basic mechanisms of the disease and the use of predictive biomarkers, especially regarding the Th2-high endotype, it is now easier than before to tailor therapy and guide clinicians toward the most suitable therapeutic choice, thus reducing the number of uncontrolled patients and therapeutic failures. In this review, we will discuss the different biological options available for the treatment of severe refractory asthma, their mechanism of action, and the overlapping aspects of their usage in clinical practice. The availability of new molecules, specific for different molecular targets, is a key topic, especially when considering that the same targets are sometimes part of the same phenotype. The aim of this review is to help clarify these doubts, which may facilitate the clinical decision-making process and the achievement of the best possible outcomes.

Keywords: cytokines; economic burden; endotypes; eosinophils; inflammation; phenotypes.

Figure 1

Inflammatory pathway in asthma. IFNγ, interferon gamma; IL, interleukin; ILC2, type II innate lymphoid cells; TH, T helper; TSLP, thymic stromal lymphopoietin.

Figure 2

Severe asthma endotype serving for the correct therapeutic choice. IgE, immunoglobulin E; Th2, T helper 2.