Response to cyclophosphamide in steroid-resistant focal segmental glomerulosclerosis: a reappraisal

The response to and clinical outcome of cyclophosphamide therapy were retrospectively assessed in 29 steroid-resistant patients with idiopathic nephrotic syndrome and focal segmental glomerulosclerosis (FSGS) to determine whether a partial response to this drug was associated with long-term clinical benefits. Twenty of the patients were nephrotic when cyclophosphamide was started and 9 were not. Three of the nephrotic patients had a complete response (i.e., sustained remission of disease) to cyclophosphamide. Nine nephrotic patients had partial responses. Of these, 8 have residual proteinuria and one has progressed to end-stage renal disease (ESRD). In contrast, of the 8 nephrotic patients who were resistant to cyclophosphamide, only one has residual proteinuria, while 7 have chronic renal failure (CRF) or ESRD. The incidence of CRF or ESRD in patients with a partial response to cyclophosphamide (1 of 9) was significantly lower (p = 0.004) than that in patients who were resistant to cyclophosphamide (7 of 8). The benefit of cyclophosphamide in patients who were not overtly nephrotic was less certain. This study indicates that a partial response to cyclophosphamide leads to improvement in the clinical outcome of many steroid-resistant nephrotic patients with FSGS.