Controlled trial of cyclophosphamide in idiopathic membranous nephropathy

Abstract

The authors evaluated cyclophosphamide treatment in a controlled prospective study of 22 adult patients with clinically and histologically defined idiopathic membranous nephropathy. By random assignment, 11 patients received no drug and 11 patients received cyclophosphamide orally, 1.5 to 2.5 mg/kg/day (mean, 1.8), for one year. Before treatment the two groups were similar in age and sex distributions, duration of illness, blood pressure, degree of proteinuria, renal function and histologic staging. After treatment, a downward trend in proteinuria was noted, with no significant difference in the quantity and rate of decrease between groups. Renal function (C(in) and C(PAH)) was stable in all patients, with no difference between groups. On comparing pretreatment and 1 yr renal biopsy specimens in eight patients in each group, regardless of treatment or clinical outcome, the appearance of the renal lesions remained the same or progressed in terms of basement membrane thickening and incorporation of subepithelial deposits, and immunofluorescence with IgG and C3 remained positive in glomerular capillaries. Cyclophosphamide dosage was decreased in five patients because of recurrent leukopenia; no other major toxicity was observed. Beyond 1 yr of treatment, renal function decreased in two of eight patients in the no drug group and in one of seven patients in the cyclophosphamide treated group. It is concluded that treatment with cyclophosphamide for 1 yr did not have a favorable effect on proteinuria, renal function or morphologic aspects of the glomerular lesion.