Efficacy Study of Two Treatments in the Remission of Vasculitis

Randomized, controlled, national, multicenter, prospective study to compare between azathioprine (conventional therapy) and rituximab in patients with systemic ANCA-associated vasculitis, in remission (achieved with an induction treatment combining corticosteroids and an immunosuppressant, mainly intravenous pulses of cyclophosphamide, and plasma exchanges and/or polyvalent immunoglobulins when indicated) after the first flare of the disease (new diagnosis) or after a relapse. It is planned to stratify patients by first flare (66% of the patients) or relapse (33% of the patients). Patients complying with the inclusion criteria may be included when they are in remission from their vasculitis. Patients who have already received biologics (antiCD20, antiTNFα) will not be included. Patients will be included at the time of remission and then randomized. They will receive maintenance treatment by azathioprine for 18 months or a rituximab infusion every 6 months until month 18 (i.e. a total of 4 infusions), at the dose of 375 mg/m2 (maximum dosage, 500 mg). ANCA status and CD19+ lymphocyte count will be monitored but will not be used to adjust therapy. After the 18 month length of maintenance phase, i.e. after stopping immunosuppressive maintenance therapy, patients will be followed for an additional 10 month period. Patients with Wegener's granulomatosis will be prescribed cotrimoxazole 160/800 tid (for 2 additional years).