Nusinersen in adult patients with spinal muscular atrophy

Objective To report our experience with adult patients with spinal muscular atrophy (SMA), some of whom were treated with nusinersen.

Methods We reviewed charts of adult patients with SMA seen in our neuromuscular clinic between 2017 and 2019 and noted their demographics, clinical characteristics, treatment, and side effects.

Results Twenty-two patients were included. Nine had type 2 and 13 type 3 SMA. Median age was 36 years (range 20–71). Most could not walk unassisted. Ten patients had significant respiratory impairment necessitating ventilation and 2 had tracheostomy. Seventeen had severe scoliosis. Ten patients were treated with nusinersen for 6–24 months (median 12 months), 3 of whom required bone laminectomy for intrathecal access. One developed bowel and bladder incontinence following the procedure. In the treated group, on average, % Medical Research Council change was 2.5% at 12 months and 3.9% at 24 months. Most untreated patients remained stable; 3 had slightly declined. Five treated patients reported subjective improvement. Treatment side effects included post lumbar puncture headache in 5 patients, 2 of whom needed blood patch, and 1 bacterial meningitis requiring inpatient treatment. Three patients stopped treatment after 12–24 months due to lack of improvement, recurrent pneumonia, or proteinuria.

Conclusion Side effects of nusinersen can be serious. Whereas half of treated patients reported modest improvement in function, there were no significant objective changes, which may point largely to a placebo effect.

Classification of evidence This study provides Class IV evidence that for some adult patients with SMA, nusinersen improves subjective function and causes serious adverse effects.