Rationale of concomitant cyclophosphamide for remission-induction in patients with antineutrophil cytoplasmic antibody-associated vasculitis: A propensity score-matched analysis of two nationwide prospective cohort studies

Abstract

Objectives We evaluated the effectiveness of cyclophosphamide for patients with microscopic polyangiitis and granulomatosis with polyangiitis. Methods Patients treated with cyclophosphamide and glucocorticoid (cyclophosphamide group) or glucocorticoid alone (non-cyclophosphamide group) for remission-induction were enrolled from two Japanese nationwide prospective inception cohort studies. The effectiveness and safety outcomes were compared before and after propensity score (PS)- matching. Results Proportion of patients achieving Birmingham Vasculitis Activity Score (BVAS)-remission and BVAS-remission plus a daily prednisolone dosage of ≤10 mg (GC-remission) by Month 6 were not significantly different between cyclophosphamide and non-cyclophosphamide groups before (n = 144 and 155) and after (n = 94 for each group) PS-matching. In myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA)-positive PS-matched patients, GC-remission by Month 6 was superior in CYC group (n = 82) than in non-CYC group (n = 91) (49 vs. 31%, p = .020). Overall, end-stage renal disease-free and relapse-free survival rates, Vasculitis Damage Index score, and proportions of serious infection were comparable between the two groups both in the unmatched and PS-matched patients. Prednisolone doses at any point after treatment initiation in the PS-matched patients were lower in the cyclophosphamide group than in a non-cyclophosphamide group. Conclusions Concomitant cyclophosphamide use may improve GC-remission by Month 6 in MPO-ANCA-positive patients and could exert glucocorticoid sparing effect.