Primary nephrotic syndrome (PNS) is the most common glomerular disease in children. Although 80-90% of affected children achieve complete remission after initial corticosteroid therapy and are classified as having steroid-sensitive nephrotic syndrome (SSNS), most experience disease relapse within the first year after onset. Approximately half subsequently develop frequently relapsing nephrotic syndrome (FRNS) or steroid-dependent nephrotic syndrome (SDNS), requiring prolonged exposure to corticosteroids and additional immunosuppressive agents. Recurrent relapses and long-term immunosuppressive treatment are associated with substantial morbidity, including infection, impaired growth and development, metabolic complications, nephrotoxicity, and reduced quality of life.
B-cell depletion therapy has emerged as an effective strategy for relapsing nephrotic syndrome. Rituximab, an anti-CD20 monoclonal antibody, has demonstrated the ability to reduce relapse rates and maintain remission in children with FRNS/SDNS, even after withdrawal of corticosteroids and other immunosuppressive agents. Based on accumulating evidence, rituximab has been incorporated into international treatment guidelines. Building upon extensive clinical experience with rituximab, our group initiated an investigator-sponsored multicenter study evaluating early rituximab treatment in children with newly diagnosed SSNS. Long-term follow-up from this study suggested potential benefits in preventing relapse and demonstrated an acceptable safety profile.
Zuberitamab is a next-generation anti-CD20 monoclonal antibody developed through molecular engineering of rituximab. Compared with rituximab, preclinical studies have demonstrated enhanced antibody-dependent cellular cytotoxicity (ADCC), a larger steady-state volume of distribution, and more sustained B-cell depletion. Zuberitamab was approved in China in 2023 for the treatment of CD20-positive diffuse large B-cell lymphoma. In addition, its use in kidney diseases has been reported in retrospective cohort studies and other early clinical experiences, including patients with membranous nephropathy. However, evidence regarding its efficacy and safety in glomerular diseases, particularly in paediatric nephrotic syndrome, remains limited.
Current treatment strategies for childhood nephrotic syndrome primarily focus on managing relapses after they occur rather than preventing them during the early phase of disease. Whether early intervention with a potent anti-CD20 monoclonal antibody can modify the disease course and reduce future relapses remains uncertain. This study is designed to evaluate the efficacy and safety of early Zuberitamab administration in combination with standard corticosteroid therapy in children with newly diagnosed steroid-sensitive nephrotic syndrome.
This is a multicenter, open-label, randomized controlled trial conducted across nine pediatric nephrology centers in China. Children with newly diagnosed steroid-sensitive nephrotic syndrome (SSNS) who achieve remission following standard corticosteroid treatment will be randomized at weeks 4-5 after remission to receive either Zuberitamab plus standard corticosteroid treatment or standard corticosteroid treatment alone. Participants will be followed prospectively for up to 12 months to assess disease relapse, cumulative corticosteroid exposure, safety outcomes, kidney function, and health-related quality of life.
The study aims to determine whether early addition of Zuberitamab at weeks 4-5 after remission, compared with standard corticosteroid treatment alone, can prolong time to first relapse within 12 months.