Real-world respiratory effectiveness of mepolizumab in severe eosinophilic asthma and eosinophilic granulomatosis with polyangiitis.

BACKGROUND

Severe eosinophilic asthma (SEA) and eosinophilic granulomatosis with polyangiitis (EGPA) share a common type 2 inflammatory pathway but differ in systemic involvement and corticosteroid dependence. Real-world data on mepolizumab's effectiveness in Chinese SEA and EGPA populations are limited, and no study has jointly evaluated both cohorts.

METHODS

We conducted a single-center, retrospective cohort study of 38 consecutive SEA or EGPA patients treated with mepolizumab between July 2022 and February 2025 in China. Key outcomes included asthma exacerbation frequency, oral corticosteroid (OCS) use, lung function (FEV1 % predicted), and symptom control (ACQ-5, mini-AQLQ, SNOT-22) at baseline, 6 months, and 12 months. Safety and tolerability were also assessed.

RESULTS

After 12 months, the proportion of patients with ≥1 exacerbation decreased from 66 % to 14 % (P < 0.001), and median annual exacerbation rate fell from 2.0 (IQR 2.0-4.0) to 0.0 (IQR 0.0-0.8; P < 0.001). OCS use declined from 63 % to 23 %, with median daily prednisone dose reduced from 10.0 mg to 5.0 mg (P < 0.001). Mean FEV1 % predicted increased from 69.3 % to 81.4 % at 12 months (P = 0.004); the SEA subgroup, characterized by more severe baseline obstruction, achieved a statistically significant FEV1 % predicted gain, whereas improvements in EGPA did not reach significance. Symptom scores (ACQ-5, mini-AQLQ, SNOT-22) improved significantly in both cohorts (all P < 0.001). Two patients reported mild arthromyalgia.

CONCLUSION

In this real-world Chinese cohort, mepolizumab was well tolerated and associated with substantial reductions in exacerbations and OCS requirement, significant lung function gains, particularly in SEA, and marked symptom improvement in both SEA and EGPA.