Prior reports of ANCA reduction with IL-5–targeted therapy have generally involved concurrent corticosteroid use.4, 5, 6 For example, benralizumab has been reported to reduce MPO-ANCA in a patient with EGPA who was receiving high-dose prednisolone and azathioprine for asthma control.7 Here, MPO is linked to eosinophilic granulomatosis with polyangiitis.