Mycophenolate mofetil in steroid/cyclosporine-dependent/resistant nephrotic syndrome

Attempts to minimize the effects of prolonged steroid use in steroid-dependent nephrotic syndrome (SDNS) and the need to overcome steroid resistance (SRNS) justifies immunosuppressant therapy. We report our experience in a cohort of patients with SD/SRNS during the administration of mycophenolate mofetil (MMF) in a prospective protocol initiated in January 2001. Twenty-six children with idiopathic nephrotic syndrome were included ( 21 steroid dependent and 5 steroid resistant), whose response did not change after sequential treatment with cyclophosphamide (CPM) and cyclosporine (CsA). Histopathologic patterns were: 11 minimal change disease (MCD), 1 diffuse mesangial proliferation (DMP), 13 focal segmental glomerulosclerosis (FSGS) and membranous 1 glomerulonephritis (MGN). The median age of onset of NS was 2.8 years ( range 1.2 - 12.5), and treatment with MMF was performed at a median age of 11.4 years ( range 5 - 17) with an initial dose of 600 mg/ m(2)/ 12 h, adjusted to maintain levels of mycophenolic acid (MPA) at 2.5 - 5 mcg/ml. The planned duration of study to assess treatment efficacy was 6 months. The mean MMF dose required was 624 (SD = 136) mg/ m(2)/ 12 h ( range 415-70), which maintained mean C-0-MPA levels of 2.9 (SD = 1.17) mcg/ml ( range 1.2 - 5.9 mcg/ml). In the five patients with SRNS, only one achieved complete remission. In the patients with SDNS, steroid sparing was achieved in 15 and 9 remained in remission on MMF monotherapy. Withdrawal of MMF resulted in immediate relapse in 47%. In our study, MMF was a useful immunosuppressant due to its fewer undesirable effects and similar efficacy to other drugs used. It appears effective for the maintenance of remission in SDNS patients, with a response similar to that of CsA.