Prevention of Relapses in Proteinase 3 (PR3)-Anti-neutrophil Cytoplasmic Antibodies (ANCA)-Associated Vasculitis
Prevention of Relapses in Proteinase 3 (PR3)-Anti-neutrophil Cytoplasmic Antibodies (ANCA)-Associated Vasculitis
Treatment of patients with PR3-ANCA-associated vasculitis consists of two phases: remission
 induction with highly effective, but also relatively toxic, drugs and, secondly, after
 remission is achieved, maintenance therapy with less toxic drugs. Currently,
 remission-maintenance therapy with azathioprine is stopped after approximately 18 months.
 However, the optimal duration of azathioprine maintenance therapy is unknown.

 The investigators have found that patients with PR3-ANCA-associated vasculitis who remain
 cytoplasmic anti-neutrophil cytoplasmic autoantibody (C-ANCA) positive after induction of
 remission have an increased risk to experience relapse of disease. Therefore they will test
 whether relapse risk in these patients can be reduced by extending maintenance therapy at the
 cost of acceptable therapy related toxicity. After induction of stable remission, ANCA will
 be measured by immunofluorescence (IIF). C-ANCA positive patients will be randomized for
 either standard therapy with azathioprine (until 18 months after diagnosis), or longterm
 azathioprine maintenance therapy (until 48 months after diagnosis).
Treatment of patients with PR3-ANCA-associated vasculitis consists of two phases: remission
 induction with highly effective, but also relatively toxic, drugs and, secondly, after
 remission is achieved, maintenance therapy with less toxic drugs. Currently,
 remission-maintenance therapy with azathioprine is stopped after approximately 18 months.
 However, the optimal duration of azathioprine maintenance therapy is unknown.

 The investigators have found that patients with PR3-ANCA-associated vasculitis who remain
 C-ANCA positive after induction of remission have an increased risk to experience relapse of
 disease (MC Slot et al. Arthritis Rheum. 2004 15;51(2):269-73). Therefore they will test
 whether relapse risk in these patients can be reduced by extending maintenance therapy at the
 cost of acceptable therapy related toxicity. After induction of stable remission, ANCA will
 be measured by IIF. C-ANCA positive patients will be randomized for either standard therapy
 with azathioprine (until 18 months after diagnosis), or longterm azathioprine maintenance
 therapy (until 48 months after diagnosis).
Inclusion Criteria:

 -  Newly diagnosed ANCA-associated vasculitis

 -  PR3-ANCA antibodies present

 -  Indication for treatment with cyclophosphamide and prednisolone

 Exclusion Criteria:

 -  Intolerance or allergy to azathioprine