D2.249 - Application of Desensitization Protocol with Rituximab in the Treatment of Corticosteroid-Dependent Nephrotic Syndrome in an Adolescent

Rituximab is a chimeric monoclonal antibody targeting the CD20 molecule on B lymphocytes, which is used in the treatment of lymphoma, autoimmune disorders, and, in recent years, in the treatment of nephrotic syndrome in children. The therapeutic dose ranges from 375 mg/m² to 750 mg/m². Rituximab has been associated with hypersensitivity reactions, which can be classified as either early or late infusion-related adverse events. These reactions often lead to therapeutic dilemmas for the treating physician. Desensitization protocols for rituximab have been proposed in recent years for pediatric patients, with good outcomes, particularly for the treatment of rheumatologic diseases or malignancies, rather than for nephrotic syndrome.

A 13-year-old adolescent with a history of corticosteroid-dependent nephrotic syndrome was hospitalized in August 2024 at the Pediatric Clinic of the University General Hospital of Ioannina, due to her 8th relapse of the nephrotic syndrome. She was treated according to the nephrotic syndrome relapse protocol, and on the 10th day of hospitalization, she received rituximab infusion at a dose of 375 mg/m². However, within the first 5 minutes of the infusion, she developed cough, shortness of breath, and erythema of the palms, prompting discontinuation of the drug. It is important to note that the patient had previously received rituximab (1.5 and 2 years prior) without any adverse reactions.

Two days later, she was re-administered rituximab following a desensitization protocol, which included:

• Pre-treatment with rupatadine, prednisone, paracetamol orally (due to potential headache as adverse reaction) and dimethindene intravenously, 30 minutes prior to the infusion.

• Rituximab infusion using three different dilutions: the first two at 1/100 and 1/10, and the procedure was completed with a 1/1 dilution. In total, the infusion included 15 steps, with progressively increasing infusion rates every 15 minutes, until a total dose of 580 mg was administered over 3 hours and 50 minutes.

The rituximab session was completed without complications, following the desensitization protocol.

The use of desensitization protocols for rituximab may serve as an important tool in managing corticosteroid-dependent nephrotic syndrome in children, as it allows the patient to benefit from the therapeutic benefits of the drug without allergic reactions and provides a solution to the therapeutic dilemma faced by the treating physician.