Off-trial evaluation of the B cell-targeting treatment in the refractory cases of antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis: long-term follow-up from a single centre.

The aim of the study was to evaluate long-term clinical and immunological effects of anti-B cell treatment in patients with antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis refractory to conventional immunosuppressive treatment. Rituximab (RTX) was added to the ongoing immunosuppressive treatment in 29 patients with refractory ANCA-associated vasculitis. The disease activity was measured using Birmingham Vasculitis Activity Score/Wegener's granulomatosis (BVAS/WG score), and clinical laboratory variables were recorded. The median BVAS/WG score before treatment was 6 (IQR 3-8), and 28 patients (97%) had disease flare classified either severe (62%) or limited (34%). Six of 29 patients (21%) achieved a complete remission, and 12 (41%) had a treatment response with ≥50% decrease in BVAS/WG score at 6 months. Fourteen patients (64%) with kidney involvement achieved remission, and in seven patients (50%), no flare was seen during the follow-up period. Three patients had renal flare and were successfully re-treated with RTX. Seventeen patients had disease symptoms from airways and eyes at RTX initiation, whereas only 29% displayed ≥50% treatment response. Limited clinical improvement was seen in patients with endobronchial lesions and trachea-subglottic granulomatous disease. RTX is a potent therapeutic option for ANCA-associated vasculitis refractory to conventional treatment. Best response may be expected in patients with vasculitic manifestations.