Rituximab in relapsing or refractory ANCA-associated vasculitis: a case series of 16 patients

Cyclophosphamide (CYC) and corticosteroids are generally considered standard induction therapy for anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). However, a subset of patients are refractory or intolerant to this treatment. Rituximab, a chimeric anti-CD20 antibody, has emerged as a second-line therapy, although controlled studies are scarce in patients with relapsing or refractory disease.

We report 16 patients with AAV who received rituximab for refractory or relapsing vasculitis having previously received CYC. The treatment protocols were 375 mg/m(2) × IV in five patients, 1000 mg × II in six patients, and 500 mg × II in five patients, all in combination with corticosteroids. A majority of patients used other concurrent immunosuppression, most commonly mycophenolate mofetil. Disease activity was assessed using the Birmingham Vasculitis Activity Score (BVAS 2003) at baseline and during follow-up together with C-reactive protein (CRP) and ANCA. Complete remission was defined as a BVAS score of 0 and partial remission as a reduction in BVAS of at least 50%.

Twelve patients achieved complete remission, three patients partial remission, and one patient died during follow-up (median of 20 months, range 3-48 months). Six patients relapsed and received rituximab again. Four of these were positive for capture proteinase 3 (PR-3) ANCA but negative with conventional PR-3 ANCA upon retreatment. Seven patients had an adverse event, including two hepatitis B reactivations and one fatal sepsis.

Treatment with rituximab in AAV was associated with prolonged remission in a subset of patients otherwise difficult to manage.