Mycophenolate mofetil in children with frequently relapsing nephrotic syndrome: a report from the Southwest Pediatric Nephrology Study Group.

Children with frequently relapsing nephrotic syndrome (FRNS) often develop adverse effects from prednisone. Attempts to induce long-term remission in such patients have had varying levels of success. In this multicenter, prospective, open-label study, 14 centers enrolled 33 patients with FRNS, all of whom were in remission at the time of entry. Six of the patients were steroid dependent. The patients received mycophenolate mofetil (MMF) 600 mg/m(2) twice daily (maximum 1 g twice daily) for 6 mo. A tapering dosage of alternate-day prednisone was given to each patient during the first 16 wk of MMF therapy. Patients were monitored for relapses of NS during and after MMF therapy. Treatment failure was defined as a relapse of NS. The patients had the following features at study entry: Age 6.8 +/- 2.7 yr (range 2 to 15 yr); 56% male, 44% female; and 50% white; 25% black, and 25% other. Estimated GFR at entry was 138 +/- 42 ml/min per 1.73 m(2). Twenty-four (75%) of 32 patients stayed in remission throughout the 6 mo of MMF therapy. The relapse rate in these patients improved from one episode every 2 mo before MMF to one every 14.7 mo after MMF. Eight patients stayed in remission during the post-MMF period, for periods of 18 to 30 mo, whereas 16 relapsed after stopping MMF. Eight (25%) of 32 patients relapsed while taking MMF. It is concluded that MMF is effective for maintaining remission in patients who have FRNS and receive treatment for at least 6 mo and is associated with a low incidence of adverse events.