[Clinical analysis of eculizumab in the treatment of atypical hemolytic uremic syndrome in children].

Objective: To evaluate the efficacy and safety of eculizumab, a terminal complement inhibitor, in the treatment of pediatric atypical hemolytic uremic syndrome (aHUS), and explore strategies for treatment discontinuation. Methods: This was a case series study. Clinical data of the 10 children diagnosed with aHUS who were hospitalized and treated with eculizumab at Children's Hospital affiliated to Zhengzhou University between March 2024 and September 2025 were retrospectively collected. The data included demographic characteristics, laboratory findings, genetic test results, medication process and drug discontinuation status as well as follow up (till September 2025) after drug withdrawal, etc. The clinical features and prognosis of these patients were summarized. Results: Ten aHUS children included 7 males and 3 females, with an onset age of 61.0 (16.8, 79.8) months. Decreased complement C3 levels were observed in 7 patients, and elevated anti-factor H antibodies in 3. Genetic testing was performed in all patients and identified pathogenic variants in 3 patients: heterozygous CFH mutation, homozygous CFHR1 and CFHR3 deletions, and heterozygous DGKE mutation. The time from symptom onset to eculizumab initiation (defined as delayed administration time) was 7.5 (5.0, 10.5) d. Before treatment, the estimated glomerular filtration rate was 58.0(31.8,64.0)ml/(min·1.73 m²). After 4 weeks of eculizumab therapy, all patients were free from dialysis, and 9 cases achieved normal renal function. Platelet counts normalized after 11.5 (7.5, 17.5) d. Based on physician-patient shared decision-making model, 6 patients discontinued eculizumab, with a treatment duration of 117(53, 155) d. During a follow-up of 139(118, 440) d post-discontinuation, no relapses occurred. Five regained normal renal function, and 1 progressed to stage 2 chronic kidney disease. One patient experienced self-resolved mild limb pain during the treatment, and no other adverse events were observed. None of the children had a history of vaccination with the quadrivalent meningococcal vaccine before treatment. Due to the critical condition, all patients received oral azithromycin for infection prophylaxis, and no case of meningococcal infection occurred. Conclusions: Eculizumab can significantly improve renal function, reduce the incidence of renal failure in the treatment of pediatric atypical hemolytic uremic syndrome and is associated with high safety and few adverse reactions. The decision on treatment discontinuation can be made following the physician-patient shared decision-making model, with the timing reasonably chosen based on the patient's clinical condition and family financial status.