Nusinersen for Spinal Muscular Atrophy Type I with Chronic Respiratory Failure: A Retrospective Study in South Korea

Purpose: To analyze the efficacy and safety of nusinersen in patients with spinal muscular atrophy (SMA) type I with chronic respiratory failure. Materials and Methods: We retrospectively reviewed seven patients diagnosed with SMA type I and chronic respiratory failure who were on permanent ventilation and treated with nusinersen at Gangnam Severance Hospital between January 2018 and July 2023. Patient demographics and clinical characteristics were recorded, and treatment progress was evaluated according to Ham-mersmith Infant Neurological Examination (HINE-2) and Children's Hospital of Philadelphia Infant Test of Neuromuscular Dis-orders (CHOP-INTEND) scores. Results: Patients initially developed hypotonia at a mean age of 3.7 months. Mean age at start of nusinersen was 7.3 years; the mean duration of follow-up after starting nusinersen was 46.2 months. At 6-, 18-, 38-, 58-, and 74-month follow-up, the mean changes in CHOP-INTEND scores were 1.0, 2.9, 1.8, 1.5, and 1.5, respectively, and the proportions of patients who showed disease amelioration were 28.6%, 71.4%, 75.0%, 100%, and 100%, respectively. Conclusion: Nusinersen is safe and effective in patients with SMA type I, even those with chronic respiratory failure and those on permanent ventilation. No significant adverse effects of nusinersen were observed.