Favourable renal survival in paediatric microscopic polyangiitis: efficacy of a novel treatment algorithm

Microscopic polyangiitis (MPA) is one of the most common forms of antineutrophil cytoplasm autoantibodies (ANCA)-associated vasculitis in children. Cyclophospamide and glucocorticoid-based treatment protocols are still considered gold standard in managing this multi-system disorder. But treatment-related toxicity is a major cause of chronic morbidity and early mortality in MPA. Hence, the search for an effective and safe alternative immunosuppressant is essential. A retrospective analysis of baseline clinico-pathological presentation and treatment-outcome was performed among 11 paediatric MPA patients. All of whom were treated with a pre-specified cyclophosphamide free, rituximab- and mycophenolate mofetil (MMF)-based management protocol as per centre practice. We describe the clinical course of 11 children with MPA over a median follow-up period of 20.9 months. Both patient survival and renal survival at 1 year follow-up were 100%. In spite of the varying degree of renal involvement at presentation, kidney function was recovered in all patients with a median estimated glomerular filtration rate (eGFR) of 79.5 mL/min/1.73m(2). At last follow-up, 91% (10/11) of patients were in complete remission and one (9%) child continued partial remission state. There was no treatment failure. In total, 73% (8/11) of patients were off steroids at last follow-up and 82% (9/11) of patients never relapsed during follow-up period. Efficacy and medium-term safety of rituximab- and MMF-based protocol in managing children with MPA was evident in this study.