Toxicity limits the use of cyclophosphamide for anti-neutrophil cytoplasmic antibody (ANCA)–associated vasculitis. In this
comparison of pulse versus daily oral cyclophosphamide regimens, equal proportions of patients had remissions, but the pulse
regimen seemed safer, mainly because of fewer cases of leukopenia. However, patients and providers were not blinded, and the
study did not measure differences in relapse rate. Pulse and daily oral cyclophosphamide treatment seem to be equally efficacious
for ANCA–associated vasculitis, but pulse therapy may be safer.