Rituximab for Steroid-Dependent or Frequently Relapsing Idiopathic Nephrotic Syndrome in Adults: A Retrospective, Multicenter Study in Spain

Background Patients with difficult-to-treat idiopathic nephrotic syndrome (INS), steroid-dependent nephrotic syndrome (SDNS), or frequently relapsing nephrotic syndrome (FRNS) require long-term immunosuppressive therapy. Rituximab offers an alternative treatment for patients with disease that has not responded to multiple therapies. Objective Our objective was to determine the efficacy and safety of rituximab in adult patients with difficult-to-treat (SDNS or FRNS) INS. Methods We performed a retrospective multicenter study that included 50 adults with difficult-to-treat INS in six Spanish centers. All patients were treated with steroids in combination with another immunosuppressant: 28 patients received rituximab as the additional treatment (rituximab group), and the other 22 patients not treated with rituximab served as the control group. Results Of the patients treated with rituximab, 23 (82%) experienced complete remission, 20 (71%) had no relapses after receiving rituximab, and 13 (46%) did not receive any immunosuppressant. Of those in the control group, 14 (63%) experienced complete remission, including eight without immunosuppressants (29%). The rituximab group experienced highly significant reductions in total number of relapses per year ( p < 0.001), proteinuria ( p = 0.03), steroid doses ( p = 0.002), and tacrolimus doses ( p = 0.001). Mean follow-up after rituximab was 31 ± 26 months (range 8–86). The need for steroids and other immunosuppressants to achieve sustained remission was lower in the rituximab group than in the control group. Conclusions Rituximab treatment was safe and well tolerated. It effectively reduced the incidence of relapses and need for maintenance immunosuppressive therapy in adults with difficult-to-treat INS.