Rituximab treatment in children with difficult-to-treat nephrotic syndrome

Purpose: Rituximab (RTX) has been offered as rescue therapy for patients with difficult-to-treat nephrotic syndrome (frequent relapsing, steroid-dependent and steroid resistant). We aimed to assess the efficacy and long-term outcomes of RTX treatment in children with difficult nephrotic syndrome and shared our experiences Materials and Methods: Medical records of children with difficult nephrotic syndrome who were treated with RTX were retrospectively evaluated. The relapse-free survival rate at 12 month and monitoring of B-cell depletion were assessed. Results: In the study included 20 children of which 8 had steroid-dependent (SDNS), 6 had frequent relapsing (FRNS), and 6 had steroid-resistant nephrotic syndrome (SRNS). The median number of relapses at 1 year before and after treatment in FRNS/SDNS patients receiving RTX treatment were compared. The median number of relapses decreased from 2 (1-4) to 0 (0-1) times/year. The mean duration of the follow-up period after RTX treatment was 23 (12-59) months, and 8 patients developed relapse. Repeated doses of RTX were administered to 5 patients who relapsed after RTX treatment. In these patients, CD19+B cells re-emerged during remission, while depletion of memory B-cells remained. Conclusion: The RTX treatment prolonged the remission time in FRNS/SDNS patients, but it was ineffective in SRNS patients. It was determined that the RTX doses can be repeated to maintain remission in these patients, and the best memory B-cell counts can help in timing the repeat doses.