A patient with eosinophilic granulomatosis with polyangiitis successfully weaned from corticosteroids through remission induction therapy with mepolizumab.

The patient was a 74-year-old man who was admitted to our hospital for fever, purpura, abdominal pain, and bilateral numbness. Although the patient tested negative for anti-neutrophil cytoplasmic antibody (ANCA), he presented with an elevated peripheral eosinophil count, increased inflammatory responses, duodenitis, cholecystitis, lung lesions, renal disorder, and peripheral neuropathy. The skin biopsy findings revealed vasculitis. Thus, the patient was diagnosed with eosinophilic granulomatosis with polyangiitis (EGPA). Given the advanced age of the patient, in addition to the poor general condition and hepatic and renal dysfunction, administration of immunosuppressants was considered to pose a high risk. After obtaining informed consent, remission induction therapy was initiated with mepolizumab (MPZ; 300 mg/M) in combination with high-dose corticosteroid therapy (equivalent to 70 mg/day of prednisolone). After treatment initiation, eosinophil counts and inflammatory responses decreased. Moreover, the abdominal pain and purpura resolved, and renal/hepatic dysfunction and peripheral neuropathy also improved. While the corticosteroid dose was subsequently reduced, no relapse was observed. Approximately 2 years later, the corticosteroid was discontinued. After the discontinuation of the corticosteroid, the patient continued treatment with MPZ alone and has remained in remission for approximately 6 months. Therefore, MPZ may be useful as a remission induction therapy in ANCA-negative EGPA resistant to steroids.