Clinical Outcomes of Treatment of Anti-Neutrophil Cytoplasmic Antibody (ANCA)-Associated Vasculitis Based on ANCA Type

Abstract

Objective

To evaluate whether the classification of ANCA-associated vasculitis (AAV) patients according to ANCA type (anti-proteinase 3 [PR3] or anti-myeloperoxidase [MPO] antibodies) predicts treatment response.

Methods

Treatment responses were assessed among patients enrolled in the Rituximab in ANCA-associated Vasculitis trial according to both AAV diagnosis (granulomatosis with polyangiitis [GPA]/microscopic polyangiitis [MPA]) and ANCA type (PR3-AAV/MPO-AAV). Complete remission (CR) was defined as disease activity score of 0 and successful completion of the prednisone taper.

Results

PR3-AAV patients treated with rituximab (RTX) achieved CR at 6 months more frequently than did those randomized to cyclophosphamide (CYC)/azathioprine (AZA) (65% versus 48%; P=0.04). The odds ratio (OR) for CR at 6 months among PR3-AAV patients treated with RTX as opposed to CYC/AZA was 2.11 (95%CI 1.04–4.30) in analyses adjusted for age, sex, and new-onset versus relapsing disease at baseline. PR3-AAV patients with relapsing disease achieved CR more often following RTX treatment at 6 months (OR3.57; 95%CI 1.43–8.93); 12 months (OR4.32; 95%CI 1.53–12.15); and 18 months (OR3.06; 95%CI 1.05–8.97). No association between treatment and CR was observed in the MPO-AAV patient subset or in groups divided according to AAV diagnosis.

Conclusion

PR3-AAV patients respond better to RTX than to CYC/AZA. An ANCA type-based classification may guide immunosuppression in AAV.