Efficacy of cyclophosphamide in steroid-sensitive childhood nephrotic syndrome with different morphological lesions.

We have reviewed the efficacy of cyclophosphamide in 39 steroid-sensitive frequently relapsing nephrotic children. Cyclophosphamide was used because of heavy steroid dependence and steroid toxicity. A percutaneous renal biopsy done prior to administration of cyclophosphamide showed the lesion to be minimal change in 7 children, IgM nephropathy in 17 children, and evolving from minimal change nephrotic syndrome to focal segmental sclerosis (FSGS) in 15 children. 100% of patients with minimal change nephrotic syndrome responded to cyclophosphamide, but only 58% of IgM patients responded (p less than 0.05). Only 1 of 15 FSGS patients responded (p less than 0.001 vs. minimal change nephrotic syndrome and p less than 0.01 vs. IgM). In view of the failure of cyclophosphamide to produce a remission in FSGS and its potential for long-term impairment of suppressor T cell function, we suggest that it should not be used in patients whose disease has evolved from minimal change to FSGS.