Cyclophosphamide in the treatment of idiopathic nephrotic syndrome.

Fifty-three patients 3 1/2 to 20 years of age with steroid-dependent idiopathic nephrotic syndrome (INS) were treated with cyclophosphamide and prednisone. Two dosage schedules were used: a short course (SC) at 3 to 5 mg/kg/day for six to eight weeks and a longer course (LC) at 3 to 5 mg/kg/day for eight weeks followed by 1.5 to 2.5 mg/kg for an additional four weeks. Prednisone was administered concurrently at 50 to 75 mg/sq M every other day. Twenty-nine patients were in the SC group and 24 in the LC group. The two groups did not differ significantly as to age at onset of idiopathic nephrosis nor as to the duration of the INS prior to cyclophosphamide therapy. All patients were followed for a minimum of 42 months after cyclophosphamide therapy. The SC was associated with a higher relapse rate during the first year than the LC (42% and 8% respectively, .01 larger than P less than .025). At 42 months 63% of the LC group were in remission compared with 21% in the SC group.