Efficacy and Safety Analysis of Mepolizumab in the Treatment of Eosinophilic Granulomatosis with Polyangiitis

<bold>Objective:</bold> To evaluate the effectiveness and safety of mepolizumab for treating eosinophilic granulomatosis with polyangiitis (EGPA). Method: Prospective study on 20 EGPA patients receiving mepolizumab at Guangzhou Medical University's First Affiliated Hospital from Aug 2021 to Dec 2023. Data on Birmingham Vasculitis Activity Score (BVAS), blood eosinophils, FEV1pred%, and oral corticosteroid (OCS) doses were collected to assess treatment efficacy. <bold>Results:</bold> Of 20 EGPA patients (85.0% female, median age 42), after 4 months, 85.0% responded positively. Eosinophil count significantly dropped (Z=3.88, p<0.001), FEV1pred% increased (Z=2.24, P=0.025), FeNO levels fell (Z=2.54, P=0.011), and OCS dosage reduced (Z=3.83, P<0.001). At 12 months, improvements persisted in 5 patients. No significant difference emerged between standard (300mg/4w) and non-standard (100mg/4w) dose groups in clinical indicator improvements after 4 months (P>0.05). One mild rash event occurred among 125 injections, indicating good safety profile. <bold>Conclusion:</bold> Mepolizumab is efficacious and safe in EGPA treatment, reducing OCS requirement, enhancing lung function, and showing no severe adverse effects. Both standard and non-standard dosing effectively managed symptoms and reduced OCS use in EGPA patients.