Cyclophosphamide treatment of steroid dependent nephrotic syndrome: comparison of eight week with 12 week course. Report of Arbeitsgemeinschaft für Pädiatrische Nephrologie.

In a prospective study (Cytotoxic Drug Study II), 18 children with steroid dependent nephrotic syndrome and steroid toxicity were treated with cyclophosphamide (2 mg/kg body weight/day) for 12 weeks in combination with reducing doses of prednisone (group A). This group was compared retrospectively with 18 children with steroid dependent nephrotic syndrome, studied as part of the Cytotoxic Drug Study I, and who had received cyclophosphamide for eight weeks (group B). There were no differences between the groups in age at the onset of the nephrotic syndrome, age at entry into the study, and duration of the nephrotic syndrome before entry into the study. The number of relapses during the six months before the treatment was the same in both groups. Two years after treatment 12 of 18 children treated with cyclophosphamide for 12 weeks were still in remission. By contrast, only four of of 18 children treated with cyclophosphamide for eight weeks were still in remission. The cumulative rates of sustained remissions were significantly higher (67% and 22%, respectively) in group A. All relapses were observed within 400 days of stopping cytotoxic treatment. No severe side effects of cyclophosphamide occurred up to two years after treatment had been stopped. We conclude that for children with steroid dependent nephrotic syndrome and steroid toxicity cyclophosphamide treatment should be prolonged to 12 weeks to increase the likelihood of a prolonged remission.