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Severe Eosinophilic Asthma — RACP Adult Medicine MCQ

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HardRespiratorySevere Eosinophilic AsthmaRACP Adult Medicine

A 48-year-old man with severe persistent asthma on high-dose ICS/LABA, tiotropium, and oral prednisolone 10 mg daily has blood eosinophils of 450 cells/µL and total IgE of 380 IU/mL. Despite triple therapy, he continues to have frequent exacerbations. Which biologic agent is most appropriate?

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Correct answer: C — Mepolizumab (anti-IL5)

With blood eosinophils ≥300 cells/µL and frequent exacerbations despite GINA Step 5 therapy, anti-IL5 biologics (mepolizumab or benralizumab) are first-line add-on options. Mepolizumab has the longest track record and is PBS-listed for severe eosinophilic asthma in Australia. While dupilumab and tezepelumab are alternatives, anti-IL5 therapy is preferred for a predominantly eosinophilic phenotype. Omalizumab targets allergic (IgE-mediated) asthma but eosinophilic phenotype favours anti-IL5.

Reference: GINA – 2024 – Severe Asthma Management; PBS – 2025 – Biologic Listings for Severe Asthma