Rituximab treatment of ANCA-associated vasculitis.

INTRODUCTION: Rituximab, an anti-B-cell biological therapy, has been investigated in several clinical trials on antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAVs). AREAS COVERED: In this paper, the clinical trials and open-label studies on rituximab efficacy and safety in treating AAVs are reviewed. EXPERT OPINION: Rituximab achieved high remission-induction and sustained-maintenance rates for patients with these severe diseases, thereby challenging the cornerstone treatment of corticosteroids and cyclophosphamide followed by azathioprine. Rituximab should be used as first-line therapy with corticosteroids to induce remission of severe AAVs, especially in situations in which cyclophosphamide may be problematic (relapse after cyclophosphamide, women of childbearing age, risk of malignancy). Cyclophosphamide indications are likely to be restricted in the future. Whenever possible, rituximab should be preferred to azathioprine to maintain remission. The current maintenance regimen has been extended to at least 18 months but its optimal duration remains unknown and recent data suggest the possibility to extend treatment to 4 years. Future challenges include defining the best dose regimen: at present, different schedules are used as alternatives to those recognized as standards by health authorities. In addition, it remains to identify which patients will benefit the most from long-term retreatment: potentially those with relapsing disease or anti-proteinase-3 ANCA-positivity.