Effectiveness and safety of anti-IL-5/Rα biologics in eosinophilic granulomatosis with polyangiitis: a two-year multicenter observational study.

Background: Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare vasculitis characterized by asthma, systemic manifestations, and blood and tissue eosinophilia.

Objective: To assess the effectiveness and safety of mepolizumab (anti-IL-5) and benralizumab (anti-IL-5Rα) in EGPA for 24 months.

Methods: We conducted a multicenter observational study, including patients with EGPA treated with anti-IL-5/Rα biologics in 9 Italian specialized facilities. Systemic disease activity, remission and relapse rate were evaluated from 3 to 24 months after treatment initiation. Respiratory outcomes, hematological parameters, corticosteroid (OCS) and immunosuppressants consumption were also assessed.

Results: 49 patients with relapsing-refractory EGPA were included [26 (53.1%) benralizumab 30mg, 20 (40.8%) mepolizumab 100mg, 3 (6.1%) mepolizumab 300mg]. Overall, 38.8% and 57.1% achieved remission after 12 and 24 months, respectively (69.2% benralizumab and 43.5% mepolizumab). Lower OCS intake and higher blood eosinophil count at baseline were associated with remission at 24 months. Both biologics exerted beneficial effects on severe asthma outcomes. Indeed, 61.2% (61.5% benralizumab and 60.8% mepolizumab) remained exacerbation-free during treatment. Lung function parameters showed improvements in the overall cohort (all 0.05), but began to decline from month 12, especially with mepolizumab. Marked reduction in blood eosinophils was registered with mepolizumab (0.0001), while benralizumab depleted both eosinophils (0.0001) and basophils (<0.0001). In general, 69.6% (76% benralizumab and 61.9% mepolizumab) of OCS-dependent patients lowered their daily dose by 75%, while 28.3% discontinued these drugs. Immunosuppressants were suspended in 88.2% of cases. Adverse events were reported in 8.2% of patients.

Conclusions: These real-world data suggest that anti-IL-5/Rα biologics are effective and safe in the long-term as add-on treatments for patients with EGPA.