Real-world safety and effectiveness of mepolizumab for patients with eosinophilic granulomatosis with polyangiitis in Japan: a subgroup analysis of the MARS study

ObjectivesEvaluate the long-term safety and effectiveness of mepolizumab in subgroups of patients with eosinophilic granulomatosis with polyangiitis, including: disease duration, oral corticosteroid use, relapse, worsening or new-onset symptoms, anti-neutrophil cytoplasm antibodies status, and immunosuppressive therapy use. MethodsData from the 96-week MARS study in Japan were analysed for patients receiving mepolizumab for ≥96 weeks, focusing on adverse events, clinical symptoms, average daily oral corticosteroid dose, and relapse. ResultsOral corticosteroid exposure decreased in most subgroups, particularly in the anti-neutrophil cytoplasm antibodies negative subgroup. Patients on higher average oral corticosteroid doses (>7.5 mg/day versus ≤ 7.5 mg/day, during the observation period) experienced more adverse events, including infection-related adverse events and clinical symptoms, and higher relapse rates. No relapses were observed in patients on an average dose of 0.0 mg/day oral corticosteroids. Reduced oral corticosteroid use was associated with improved clinical outcomes, particularly in patients who remained relapse-free. ConclusionMepolizumab was effective regardless of eosinophilic granulomatosis with polyangiitis duration, anti-neutrophil cytoplasm antibodies status, or immunosuppressant use. Higher oral corticosteroid doses were linked to more adverse events, clinical symptoms, and relapses compared to lower doses. In relapse-free patients, continued mepolizumab use led to fewer adverse events, lower oral corticosteroid doses, and improved symptoms.