Long-term outcome of children with steroid-resistant nephrotic syndrome treated with tacrolimus.

We report the outcome of our single-center, long-term follow-up study of tacrolimus therapy in children with steroid-resistant nephrotic syndrome (SRNS). All cases of nephrotic syndrome (NS) with kidney biopsies treated at our center between January 2000 and July 2008 were reviewed. Children with systemic lupus erythematosus and steroid-dependent NS were excluded. Nineteen children with SRNS received tacrolimus. Histopathological analysis of the biopsy revealed the underlying conditions of these 19 patients to be focal segmental glomerulosclerosis (ten patients), C1q nephropathy (four), membranous nephropathy (two), minimal change disease (one), membranoproliferative glomerulonephritis (one), and immunoglobulin A nephropathy (one). The mean follow-up was 55 months, and the median age of the patient cohort was 10 years. We observed complete remission in 11 (58%) patients, partial remission in six (32%), and failure to respond in two (9%). The median time to response was 8 weeks. Side effects were mild and transient (one case of acute kidney injury and three cases of hyperglycemia). The initial rate for combined partial and complete remission of the NS in children with SRNS was 81%, which was sustained in 58% of the patients on follow-up. Among children with FSGS, the sustained remission rate was 50%, while 40% progressed to end-stage renal disease (ESRD) (mean time 52 months). Based on the results of this study, we conclude that tacrolimus is an effective and well-tolerated therapeutic option for the treatment of SRNS in children. However, the occurrence of relapses of the NS with progression to ESRD during the long-term follow-up indicates the need for careful monitoring of such patients.