Zuberitamab in the First Episode of Paediatric Nephrotic Syndrome

Inclusion Criteria: * Newly diagnosed steroid-sensitive nephrotic syndrome (SSNS) according to the 2023 IPNA criteria, who achieved complete remission after steroid induction therapy prior to study entry, defined as UPCR (based on first morning void or 24 h urine sample) \<= 20 mg/mmol (0.2 mg/mg), or negative or trace dipstick on three or more consecutive days. * An estimated glomerular filtration rate \>= 90 mL/min/ 1.73 m2 at study entry. * Peripheral blood CD20+ (detected as CD19+) cells \>= 1% of total lymphocytes. * No use of other immunosuppressants within 3 months prior to study entry, other than steroids for nephrotic syndrome. Exclusion Criteria: * Known etiology including congenital nephrotic syndrome, IgA nephropathy, Henoch-Schönlein purpura nephritis, lupus nephritis, or other secondary nephrotic syndromes. * Patients exhibiting any of the following abnormal clinical laboratory values: leukopenia (white blood cells \<= 3.0 × 10\^9/L), absolute neutrophil count \< 1.5 × 10\^9/L; moderate to severe anemia (hemoglobin \< 9.0 g/dL); thrombocytopenia (platelet count \< 100 × 10\^12/L); alanine aminotransferase (ALT) or aspartate aminotransferase (AST) \> 2.5 times the upper limit of normal; positive for any autoimmune markers (ANA, ENA, ANCA, etc.) or decreased complement C3 levels. * Evidence of the following infections: severe or opportunistic infection within the previous 6 months (active tuberculosis or history of tuberculosis or suspected tuberculosis; chroni…