Objective: To compare long and short durations of adjunctive cyclophosphamide for the treatment of severe Churg-Strauss syndrome (CSS).
Methods: In this prospective multicenter therapeutic trial, 48 patients with CSS with at least 1 poor-prognosis factor at baseline were treated with glucocorticoids and either 12 or 6 intravenous cyclophosphamide pulses.
Results: At 8 years, complete remission rates and severe side effects of therapy were comparable for both groups. The overall difference in relapses was not significant between the 12-pulse and the 6-pulse regimens (P = 0.07), but when considering only the number of mild relapses this difference became statistically significant (P < 0.02). Although the total number of inclusions was not reached, the study was stopped prematurely in response to the superiority of the 12-pulse regimen.
Conclusion: We concluded that 12 cyclophosphamide pulses were better able to control severe CSS than a 6-pulse regimen. The optimal duration of therapy remains to be determined.