Biologics in Hypereosinophilic Syndrome and Eosinophilic Granulomatosis with Polyangiitis

Hypereosinophilic syndrome (HES) and eosinophilic granulomatosis with polyangiitis (EGPA) are complex disorders defined by blood and tissue eosinophilia and heterogeneous clinical manifestations. Historically, the mainstay of therapy for both conditions has been systemic glucocorticoids. However, recent availability of biologics that directly or indirectly target eosinophils has provided new avenues to pursue improved outcomes with decreased toxicity. In this article, we summarize the evidence supporting the use of specific biologics in HES and/or EGPA and provide a framework for their clinical use in patients.