Mycophenolate Mofetil Following Rituximab in Children With Steroid-Resistant Nephrotic Syndrome

Abstract

BACKGROUND: Rituximab is being increasingly used in children with idiopathic nephrotic syndrome resistant to standard treatments. In spite of good initial response, rituximab responders always remain prone to further relapse, necessitating either repeat course of rituximab or addition of another steroid-sparing immunosuppressant. METHODS: A retrospective analysis of baseline clinico-pathologic presentation and treatment outcome (complete remission, partial remission, or no response) was performed among 24 children with refractory-idiopathic SRNS over a follow-up period of 24 months. Children received 2 to 4 rituximab infusions (375 mg/m2 weekly) depending on circulating B-cell level. At 3-month follow-up, a second course of rituximab was administered (if >5 B cells/mm3) along with MMF (1200 mg/m2 per day) maintenance therapy. RESULTS: Of 24 patients, 54% (13/24) and 46% (11/24) had minimal change disease and focal segmental glomerulosclerosis, respectively, on renal histopathology. After the first course of rituximab, 21% (5/24) of children achieved complete remission; however, most (4/5) of them relapsed again at a median interval of 53 (interquartile range 46–72) days. Depending on response to the first course of rituximab, MMF was started on 15 children at 3 months. After 6 months, 67% (10/15) of children on MMF achieved complete remission and 33% (5/15) remained at partial remission. At 24 months overall, 25% (6/24) and 42% (10/24) of children were in complete remission and partial remission, respectively; 33% (5/15) of children continued sustained complete remission after postrituximab-MMF maintenance therapy in comparison with no sustained complete remission with rituximab alone at 24 months (P < .001). CONCLUSIONS: MMF may be an effective and safe maintenance therapy to consider as an additive immunosuppressant after induction with rituximab in maintaining remission among children with refractory SRNS.