Benralizumab

Benralizumab binds IL-5Rα on eosinophils and basophils, blocking IL-5 signaling and recruiting NK cells through its afucosylated Fc region to mediate antibody-dependent cellular cytotoxicity, producing near-complete eosinophil depletion. Indication: add-on maintenance therapy for severe eosinophilic asthma (peripheral eosinophil count typically ≥150–300/μL despite inhaled steroids), reducing exacerbations and allowing oral steroid tapering. Dosing is subcutaneous every 4 weeks for the first three doses, then every 8 weeks — less frequent than mepolizumab/reslizumab. Compare: mepolizumab and reslizumab bind IL-5; benralizumab binds the receptor and additionally depletes eosinophils. Major adverse effects: injection-site reactions, headache, pharyngitis; rare hypersensitivity.