Beneficial effect of second courses of cytotoxic therapy in children with minimal change nephrotic syndrome.

Therapeutic guidelines are not available for children with minimal change nephrotic syndrome (MCNS) who experience frequent relapses or develop steroid resistance after a course of cytotoxic therapy. The records of nine children with biopsy-proven MCNS who received two courses of cytotoxic therapy with either chlorambucil or cyclophosphamide were reviewed to evaluate the length of remission, associated side-effects and long-term outcome. Initial cytotoxic therapy was given to five frequent-relapsing patients and four steroid-resistant patients 2-48 months (mean 16 months) following diagnosis of nephrotic syndrome. The second drug was given 4-85 months (mean 27 months) after the first. Steroid-resistant patients attained remissions of 0-81 months (mean 23 months) following the first agent and 13-67 months (mean 32 months) following the second. Frequent-relapsing patients experienced remissions of 0.5-24 months (mean 7.4 months) following the first cytotoxic drug and 3-72 months (mean 22 months) after the second. Remissions following the second agent were equal to or longer than those following the first in the seven patients who received both chlorambucil and cyclophosphamide. In the 19- to 128-month follow-up (mean 66 months), all four steroid-resistant patients experienced infrequent relapses which responded to prednisone. One frequent-relapsing patient remains in remission, three have chronic proteinuria and one still has a frequent-relapsing course. For the select group of patients who become frequent relapsing or steroid resistant after one course of cytotoxic therapy, a second course of cytotoxic therapy may allow time for catch-up growth, as well as improve steroid responsiveness once relapses occur.