Respiratory and Bulbar Support in Spinal Muscular Atrophy Type I Treated with Nusinersen

The aim of this study is to assess the evolution of respiratory and feeding support in children with spinal muscular atrophy (SMA) type 1 after 24 months of nusinersen treatment.

Data on SMA type 1 children treated with nusinersen between 2017 and 2023 from the Canadian Neuromuscular Disease Registry were extracted. The cohort was divided into two groups based on age at treatment initiation: ≤2 years and >2 years. The primary outcome was the (i) time to death or needing full-time (≥16 hours/day) ventilation and (ii) time to needing feeding tube support. The secondary outcomes were differences in respiratory and feeding support requirements between the two groups at 24-month follow-up.

Thirty-two children were included, and the median age (range) for treatment initiation was 3.2 months (0.8- 13.1) in children who initiated treatment at ≤2 years and 51.2 (28.7-183.8) in those who initiated at >2 years of age. The median age of death or full-time ventilation was 8.6 months (6-22.4) and 10.5 months (4-24) for the two groups, respectively. The median age for initiation of feeding support was 5.1 (1.7-26.4) and 14.5 months (3.9-130.6), respectively. At 24 months (n = 23), there were no significant differences between the need for respiratory or feeding tube support between the two treatment groups.

Most children with SMA type 1 treated with nusinersen across Canada have continued need for respiratory and feeding support over time when initiated after symptom onset.