Gene therapy effective in older patients with spinal muscular atrophy

The observational RESTORE study demonstrated efficacy of onasemnogene abeparvovec (OA) in patients with spinal muscular atrophy (SMA) aged 6 months or older at the time they received this gene therapy. Interventional trials of OA had already demonstrated safety and efficacy of OA in patients <6 months of age.

RESTORE (NCT04174157) is a comprehensive, prospective, multicentre, observational registry of patients with genetically-confirmed SMA across several countries. At the time of OA infusion, 117 patients were 6 months or older. Of these, 51 were 6–12 months old, 57 were 12–24 months, and 9 were 24 months or older. Most participants (n=73) had 2 copies of the SMN2 gene; one third (n=38) received OA monotherapy, while 26 combined OA with nusinersen, risdiplam, or both, and 53 patients switched from nusinersen to OA. Prof. Laurent Servais (MDUK Oxford Neuromuscular Centre, UK) presented the results [1].

At infusion, two thirds of patients (n=76/114) were diagnosed with SMA type 1; 7/114 did not yet have any symptoms. Despite their older age and higher weight (41/84 patients ≥8.5 kilogram), almost all showed improvements.

Motor skills were evaluated with the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND), ranging from 0 to 64, with higher scores indicating better function; 28 children had at least ≥2 evaluable CHOP INTEND assessments. Of this group, 25 had maintained or increased their score. There were 18 patients with an improvement of at least 4 points; 11 of them were 6–12 months old and 7 were 12–24 months.

No new or unexpected adverse events (AEs) were detected. Of 116 patients, 71 had at least 1 treatment-emergent AE; 33 had at least 1 serious AE, of which 20 were deemed related to OA treatment.

1. Servais L, et al. Effectiveness and safety of onasemnogene abeparvovec in older patients with spinal muscular atrophy (SMA): Real-world outcomes from the RESTORE registry. S39.002, AAN 2022, 02–07 April, Seattle, USA.

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Posted on 2 June, 2022