Treatment for
ANCA-associated vasculitides is now well defined, but must be adjusted for each patient according to the type of
vasculitis, its precise form (e.g., limited versus systemic
Wegener's granulomatosis) and severity, and patients' characteristics, such as age and renal function. The therapeutic decision must also take into account the risk of adverse events inherent to each treatment. The efficacy of adequate induction treatment has been demonstrated: more than 80% of patients now achieve remission. Relapse rates nonetheless remain high, especially in
Wegener's granulomatosis. Patients with
microscopic polyangiitis or
Churg-Strauss syndrome with no poor prognostic factors can be treated with
corticosteroids alone, with
immunosuppressants added only in case of treatment failure. Patients with
Wegener's granulomatosis or
microscopic polyangiitis or
Churg-Strauss syndrome and one or more poor prognostic factors must receive a combination of
corticosteroids and
immunosuppressants, mainly intravenous pulsed
cyclophosphamide.
Plasma exchange is indicated as an adjuvant
therapy for patients with severe renal involvement. Once remission is achieved, maintenance
therapy can replace
cyclophosphamide by a less toxic immunosuppressive
drug, such as
azathioprine or
methotrexate. For these latter patients, the optimal duration of induction
therapy remains to be determined, but should not be shorter than 18 months. Conversely, there is no need to prescribe high-dose
corticosteroids for months.
Prednisone must be started at 1 mg/kg/d then rapidly tapered so that patients are not receiving more than 15 mg/d after 3-4 months of
therapy.
Biological therapies also appear to have a place in the therapeutic armamentarium for
ANCA-associated
systemic vasculitides, at least for patients whose disease is refractory to conventional
therapy. However, the precise indications for anti-
TNFalpha or anti-CD20
monoclonal antibodies and their optimal regimens (doses and durations) have not yet been defined. Anti-IL5,
interferon-alpha and
anti-IgE monoclonal antibodies might also be useful for
Churg-Strauss syndrome. These biologics must be prescribed extremely cautiously and only in trial settings, especially in view of the adverse effects, few but severe, recently been reported with them.