Objective: There is growing concern about the toxic side effects of daily oral cyclophosphamide (CYC) treatment. Intravenous (i.v.) pulse administration of CYC has been shown to be effective in patients with systemic lupus erythematosus, but contradictory results have been reported in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis.
Methods: The efficacy and toxicity of i.v. pulse administration of CYC (0.75 gm/m2) versus daily oral CYC treatment (2 mg/kg body weight) were investigated in a prospective, randomized, multicenter study in patients with ANCA-associated vasculitis and renal involvement.
Results: The cumulative CYC dose was reduced by 57% in patients with i.v. pulse treatment (n = 22) compared with patients treated with daily oral therapy (n = 25). Patient survival, remission rate, time of remission, relapse rate, and outcome of renal function were not different between the 2 treatment groups. However, the rate of leukopenia (P < 0.01) and severe infections (P < 0.05 by 1-tailed test) was significantly reduced in the i.v. pulse group compared with the group receiving daily oral treatment. Moreover, gonadal toxicity was reduced in the i.v. pulse group, as indicated by significantly lower levels of follicle-stimulating hormone.
Conclusion: This randomized study shows that i.v. CYC administration is an effective therapeutic tool with low toxicity in patients with ANCA-associated vasculitis and renal involvement.