Steroid-resistant nephrotic focal segmental glomerulosclerosis: a treatable disease.

If not aggressively treated, oral steroid-resistant (SRst) nephrotic focal segmental glomerulosclerosis (FSGS) is likely to progress to end-stage renal failure. Three observations challenge the conclusion of the International Study of Kidney Diseases in Children (ISKDC) that SRst FSGS is unresponsive to further immunosuppression: (1) The ISKDC definitions of response and relapse, which fit the patterns in minimal change disease, precluded appropriate recognition of partial or gradual responses. (2) In two ISKDC studies, a small number of children with FSGS in one case, and the use of a year of alternate-day prednisone as a control in the other, may have obscured the effects of cyclophosphamide. (3) Recent studies of more aggressive therapies have provided strong evidence of benefit. High-dose methylprednisolone infusion therapy, with alternate-day prednisone alone or with alternate-day prednisone plus an alkylating agent (the M-P/ triple therapy protocol) has achieved sustained, complete remissions with stable renal function in 66% of children with SRst FSGS, and near-complete resolution of proteinuria in another 9%. Cyclosporine (CsA) plus alternate-day prednisone has produced complete or near-complete remissions in 35% of similar cases. Whether or not controlled studies will confirm the apparently greater efficacy of the M-P/triple therapy protocol, the favorable outcomes with both the M-P and the CsA regimens support the conclusion that a conservative approach to SRst FSGS is no longer appropriate.