Randomized clinical trial to compare efficacy and safety of repeated courses of rituximab to single-course rituximab followed by maintenance mycophenolate-mofetil in children with steroid dependent nephrotic syndrome

BACKGROUND: Approximately 30% of children with idiopathic nephrotic syndrome develop a complicated course with frequent relapses or steroid dependency. Rituximab, a B cell depleting monoclonal antibody, is a safe and effective alternative to steroids or other immunosuppressants for achieving and maintaining remission in this population at short term. Despite the good initial response relapses inevitably occur after regeneration of B lymphocytes, necessitating either repeat courses of rituximab or addition of another steroid-sparing immunosuppressant. METHODS: This is a prospective, single-center, open-label, two-parallel-arm randomized controlled phase III study among children with steroid dependent nephrotic syndrome who are maintained in remission with oral steroids. One hundred children will be randomized to either Rituximab and maintenance Mycophenolate mofetil (A) or repeated courses of prophylactic Rituximab only (B). In arm A, mycophenolate mofetil (1200 mg/m(2) per day) will be started 3 months after Rituximab administration. In arm B, Rituximab infusions will be administered at 0, 8 and 16 months if B cell count normalize at the given time points. Prednisolone will be discontinued in both groups 2 weeks following first course of rituximab. Primary aim is to evaluate the difference in 24-month relapse-free survival. Main secondary endpoints are cumulative prednisolone dose, frequency of relapses and changes in anthropometry. Circulating B lymphocyte populations will be studied as biomarkers or predictors of rituximab responsiveness and adverse events will be analysed. DISCUSSION: The study will provide evidence as to the comparative safety and efficacy of two alternative steroid-sparing therapeutic options in children suffering from steroid dependent nephrotic syndrome. The two-year study design will address the long-term results obtained with the alternative treatment protocols. TRIAL REGISTRATION: This trial was prospectively registered to the Clinicaltrial.gov (NCT03899103 dated 02/04/2019; https://clinicaltrials.gov/) and Clinical Trials Registry of India (CTRI/2019/04/018517 dated 09/04/2019).