Subcutaneous ofatumumab for remission maintenance in pediatric idiopathic nephrotic syndrome: a case series

Rituximab (RTX) is effective for pediatric frequently-relapsing or steroid-dependent nephrotic syndrome (FR/SDNS); however, some patients develop RTX resistance or severe hypersensitivity. Ofatumumab (OFA), a fully humanized anti-CD20 monoclonal antibody, represents a potential alternative, yet its use in children remains poorly documented. This study evaluates the feasibility and safety of low-dose subcutaneous (SC) OFA in children with complicated FR/SDNS who are RTX resistant or intolerant.

We retrospectively analyzed five pediatric patients (median age 14.8 years) with FR/SDNS and a history of RTX resistance or hypersensitivity. Each patient received a standardized SC OFA dose of 20 mg. B-cell depletion (CD19⁺ <1%), serum IgG levels, and adverse events-graded according to the Common Terminology Criteria for Adverse Events (CTCAE)-were monitored throughout follow-up. The primary endpoint was relapse-free remission within 12 months of the last OFA dose.

SC OFA achieved peripheral B-cell depletion in all patients, with a median duration of 5 months. Within 12 months, 80% (4/5) of patients maintained remission. One patient with previous severe anti-CD20 hypersensitivity tolerated SC OFA with mild (Grade 2) symptoms after ibuprofen premedication. No severe infections or exacerbations of hypogammaglobulinemia were documented.

Low-dose SC OFA is a feasible preemptive therapy for remission maintenance in pediatric FR/SDNS, particularly for those with RTX resistance or intolerance. This outpatient-compatible route may reduce hypersensitivity risks and healthcare costs. Larger prospective trials are warranted to confirm long-term efficacy.