P3‐7: Mepolizumab may not induct long term remission in patients with eosinophilic granulomatosis with polyangiitis with high relapse rates

Background: We evaluated the predictive factors of clinical efficacy of mepolizumab in patients with eosinophilic granulomatosis with polyangiitis (EGPA), a rare disease characterized by the presence of allergic granulomatosis and necrotizing vasculitis, in whom remission could not be induced despite treatment with corticosteroids (CS) and immunosuppressants. Methods: Of the 66 EGPA patients who visited Hiratsuka City Hospital, 35 received mepolizumab and were classified into two groups: 24 (68.6%) who experienced a ‘marked effect' (the daily dose of CS or IS could be decreased or the interval between intravenous immunoglobulin treatments could be prolonged) and 11 (31.4%) who experienced a ‘weak effect' (these measures were not feasible). In both groups, we evaluated the number of eosinophils in the peripheral blood, relapse rates, daily dose of CS at disease onset and before and after administration of mepolizumab. Results: All patients who received mepolizumab had clinical effect on vasculitis symptoms. Relapse rates before mepolizumab administration and dose of CS after mepolizumab administration in the ‘marked effect' group was significantly lower than that in the ‘weak effect' group (p < 0.01). The number of eosinophils in the peripheral blood at disease onset in the ‘marked effect' group was higher than that in the ”weak effect” group (p < 0.05), but not before and after administration of mepolizumab. Relapse rates in marked effect group significantly decreased after administration of mepolizumab, but did not change in weak effect group. Conclusion: Patients with EGPA with high relapse rates could not induct long term remission even if after administration of mepolizumab.