Treatment of polyarteritis nodosa and Churg-Strauss syndrome

Summary

To define the most effective treatment for polyarteritis nodosa (PAN) and Churg-Strauss syndrome (CSS), we undertook four consecutive prospective therapeutic trials including 244 patients and tried to answer several important questions: should cyclophosphamide (CYC) be given as the first-line treatment? What is the place of plasma exchanges (PE) in the treatment of systemic vasculitis? Does hepatitis B virus (HBV) related PAN require specific treatment?

Our first randomized trial in 71 patients (1981–83) compared the association of CYC with corticosteroids (CS) and PE to CS and PE, in order to evaluate the efficacy of CYC given as the first-line treatment to control disease activity and subsequent survival of PAN and CSS patients. Between December 1983 and December 1988, we conducted two trials simultaneously: one aimed at patients without HBV markers and the second at patients with HBV markers. In 78 patients without HBV markers, we compared prednisone and PE to prednisone al.one as the initial therapeutic regimen. In 33 patients with PAN related to HBV, a new therapeutic strategy was applied as an al.ternative to long-term steroid and immunosuppressive therapy: short-term steroid therapy and PE were used to control the evolution of PAN and antiviral therapy was administered to suppress the etiological agent of the vasculitis. In the last protocol, which included 62 patients and addressed severe PAN without HBV markers or CSS, we showed that PE did not improve the prognosis and control of the disease.

Twelve years after the beginning of the trials on PAN and CSS patients, we think that the therapeutic strategy should be as follows:

• In PAN without HBV and CSS: Prednisone in association with CYC improves the control of the disease despite infectious side-effects which may be reduced by better CYC dose adaptation.

• In PAN related to HBV: the first-line treatment should be the association of antiviral agents and PE. This treatment was effective and cured a majority of patients within two to three months; half of them seroconverted. The length of HBV infection before its diagnosis, delay before initiation of treatment and previous immunosuppressive therapy led to a poor seroconversion rate.

• The role of PE in the treatment of systemic necrotizing vasculitis: PE are obviously useful in PAN related to HBV where immune complex deposition has been demonstrated. When PAN is not related to HBV and in CSS, even in severe cases, there is presently no argument supporting systematic administration of PE at the time of diagnosis.