Multicenter analysis of the efficacy and safety of a non-standard immunosuppressive therapy with rituximab in children with steroid-resistant nephrotic syndrome.

The aim of the study was a multicenter analysis of the efficacy and safety of a non-standard immunosuppressive therapy with rituximab (Rtx) in children with steroid-resistant nephrotic syndrome (SRNS) with particular emphasis on the possibility of permanent discontinuation or dose reduction of other immunosuppressive drugs such as glucocorticoids and cyclosporine A after 6 months of observation. The study group consisted of 30 children with idiopathic nephrotic syndrome, who were unresponsive to standard immunosuppressive treatment, and hospitalized in the years 2010-2017 in eight paediatric nephrology centres in Poland. The children were administered a single initial infusion of rituximab at the dose of 375 mg/m2 of the body surface area. Proteinuria, the daily supply of glucocorticoids, and cyclosporine were assessed at the moment of the start of the treatment and after 6 months since its commencement. Before Rtx therapy, complete remission was found in 13 patients (43%) and partial remission was found in 8 patients (26%). These numbers increased to 16 (53%) and 12 (40%), respectively. At the start of the treatment 23 patients (76.6%) were treated with cyclosporine A. After 6 months, this number decreased to 15 patients (35%). At the start of the treatment, 18 patients (60%) were treated with prednisone. After 6 months, this number decreased to 8 patients (44%). Children with SRNS may potentially benefit from Rtx treatment despite relative risk of side effects. The benefits may include reduction of proteinuria or reduction of other immunosuppressants.