Steroid alternatives for managing eosinophilic lung diseases

International audience; Introduction Chronic pulmonary eosinophilia is a rare condition, usually highly responsive to systemic glucocorticoids, yet relapses are frequent and require long-term treatment associated with significant morbidity. Areas covered We review the main conditions causing chronic pulmonary eosinophilia and glucocorticoid-sparing agents in this setting. Expert opinion An individually tailored etiologic assessment is mandatory in all patients presenting with chronic pulmonary eosinophilia. Reducing the cumulative exposure to glucocorticoids by treating flares with short courses of systemic glucocorticoids is both safe and feasible in idiopathic chronic eosinophilic pneumonia. In frequently relapsing patients and in those requiring high doses of glucocorticoids, alternatives to glucocorticoids should be considered. Mepolizumab has been approved in several countries for the treatment of both hypereosinophilic syndrome and eosinophilic granulomatosis with polyangiitis. Given their ability to induce rapid and sustained depletion in blood and tissue eosinophils (e.g. benralizumab and lirentelimab) and/or to curb Type 2-mediated inflammation (e.g. dupilumab), other biologics hold promise in these settings. Likewise, anti-IgE targeted therapies (i.e omalizumab) should be considered in the glucocorticoid-sparing therapeutic armamentarium of allergic or hypersensitivity-related diseases, including allergic bronchopulmonary aspergillosis. Other drugs (fevipiprant, tezepelumab) are at an early phase of development. Cost-effectiveness studies are lacking. Whether glucocorticoid-free treatment regimens are achievable in these conditions is unknown.