Biologics for the Treatment of Allergic Conditions: Eosinophil Disorders.

Eosinophil-associated diseases are characterized by a common pathogenetic background, represented by eosinophil-led inflammation and overexpression of interleukin (IL)-5. IL-5 and its receptor are excellent therapeutic targets for eosinophil-associated diseases. Three monoclonal antibodies targeting IL-5 currently are available: mepolizumab and reslizumab block circulating IL-5 preventing the binding to its receptor, whereas benralizumab binds to IL-5 receptor α. They have a steroid-sparing effect in eosinophil disorders, such as eosinophilic granulomatosis with polyangiitis, hypereosinophilic syndrome, allergic bronchopulmonary aspergillosis, eosinophilic esophagitis, and chronic eosinophilic pneumonia. The biotechnological drugs targeting IL-5 are promising therapies; however, further studies are needed.