Mepolizumab
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Dosing and administration[3]
Anti-IL-5 monoclonal antibody. In eosinophilic granulomatosis with polyangiitis (EGPA) the dose is higher than the asthma dose.
| Indication | Starting dose | Titration and maximum |
|---|---|---|
| Eosinophilic granulomatosis with polyangiitis (EGPA) | 300 mg subcutaneously every 4 weeks (given as three 100 mg injections). | Maintenance dosing; used as add-on, steroid-sparing therapy. |
Monitoring
- Monitor for hypersensitivity reactions.
- Treat pre-existing helminth infection before starting.
- Do not use to treat acute vasculitis flares.
Contraindications
- Hypersensitivity to mepolizumab.
Key interactions
- No significant drug interactions established; avoid live vaccines as a general precaution with immunomodulators.
Clinical notes
How it is used in EGPA
Anti-IL-5 therapy for EGPA. ACR/VF 2021 recommends mepolizumab plus glucocorticoids as first choice for active nonsevere EGPA induction and for nonsevere relapse; EULAR 2022 recommends it for relapsing or refractory EGPA without organ- or life-threatening disease (rec 13) and as a maintenance option (rec 14). For severe EGPA, both guidelines favour cyclophosphamide or rituximab over mepolizumab for induction.[1, 2]
Monitoring
Background clinical knowledge, not a graded guideline item: monitor clinical response (asthma and sinonasal control, eosinophil count, relapse activity) and injection tolerance. No fixed laboratory monitoring schedule is set by the AAV guidelines; follow the product monograph.
Common effects
Background clinical knowledge: injection-site reactions, headache, back pain, and fatigue are the most commonly reported effects.
Important cautions
Background and monograph, not from the AAV guidelines: hypersensitivity reactions can occur; consider herpes zoster status and vaccination, and treat any pre-existing helminth infection before starting, since IL-5 blockade may impair the response to parasites. Mepolizumab is not a rescue therapy for acute bronchospasm. Reconcile full cautions with the product monograph.
References
- Chung SA, Langford CA, Maz M, et al. 2021 American College of Rheumatology/Vasculitis Foundation Guideline for the Management of Antineutrophil Cytoplasmic Antibody-Associated Vasculitis. Arthritis Rheumatol. 2021;73(8):1366-1383. doi:10.1002/art.41773 https://doi.org/10.1002/art.41773
- Hellmich B, Sanchez-Alamo B, Schirmer JH, et al. EULAR recommendations for the management of ANCA-associated vasculitis: 2022 update. Ann Rheum Dis. 2024;83:30-47. doi:10.1136/ard-2022-223764 https://doi.org/10.1136/ard-2022-223764
- NUCALA (mepolizumab) Product Monograph. Health Canada authorized product monograph. https://health-products.canada.ca/dpd-bdpp/