Maintenance therapy with mycophenolate mofetil after rituximab in pediatric patients with steroid-dependent nephrotic syndrome.

Rituximab (RTX) has a significant steroid-sparing effect in children with steroid-dependent nephrotic syndrome (SDNS). However, patients are likely to relapse with the recovery of CD20+ cells. We conducted a small prospective cohort study with a historical control to evaluate the effect of RTX infusion followed by mycophenolate mofetil (MMF) as a maintenance therapy. Nine patients with SDNS who stopped their steroid treatment but were treated with MMF after RTX infusion were prospectively observed (group A). Seven patients with SDNS who discontinued steroid and immunosuppressive agents after RTX administration served as a control (group B). During the first year after the administration of RTX, six patients in group A and one patient in group B did not suffer a relapse (p < 0.05). The number of patients who relapsed during the 1 year preceding RTX treatment did not differ between the two groups [4.1 (A) vs. 5.7 (B)], but it was significantly lower in the MMF-treated group 1 year after the RTX treatment [0.4 (A) vs. 2.3 (B), p < 0.005]. The daily amount of prednisolone after the RTX treatment was lower in group A than in group B (0.11 vs. 0.46 mg/kg/day, respectively; p < 0.05). Three patients in group A and five patients in group B relapsed to SDNS and needed additional RTX treatment(s) within 1 year (odds ratio 5.0). Based on these results, we conclude that maintenance therapy with MMF after RTX is a good clinical option.