Risdiplam treatment in adults with spinal muscular atrophy: a single-center, real-world study

BACKGROUND: Spinal muscular atrophy (SMA) is a progressive, degenerative neuromuscular disease caused by mutations in the survival motor neuron 1 (SMN1) gene leading to muscle weakness and respiratory impairments. Risdiplam is an oral disease-modifying therapy approved for the treatment of SMA in both pediatric and adult patient populations; however, real-world data on the treatment of adults with SMA are limited. METHODS: This real-world, retrospective study analyzed data from 11 patients with Types 2, 3, and 4 SMA who had been treated with risdiplam at a single center in Slovenia and had up to 30 months of follow-up. Disease progression was assessed using motor and respiratory outcome measures. RESULTS: At baseline, patients had a mean (SD) age of 51 (20) years; range, 27-82 years. Baseline motor and respiratory function varied across the patient group. From baseline to month 30, stable motor function was observed for most patients over the treatment period, with no significant overall effect of time for Revised Upper Limb Module (F = 1.44, p = 0.23) or Revised Hammersmith Scale (F = 0.54, p = 0.74). Respiratory function was generally stable over 30 months of treatment with risdiplam: from baseline to month 30, no significant overall effect of time was observed for vital capacity (F = 1.20, p = 0.32), forced vital capacity (F = 0.93, p = 0.47), peak expiratory flow (F = 0.94, p = 0.46), maximal inspiratory pressure (F = 0.65, p = 0.66), maximal expiratory pressure (F = 1.25, p = 0.31), and sniff nasal inspiratory pressure (F = 1.10, p = 0.38). CONCLUSIONS: This real-world study suggests that risdiplam treatment for adults with Types 2, 3, and 4 SMA generally stabilizes motor and respiratory function over 30 months. These results add to the limited database of risdiplam treatment outcomes in adults with SMA, support the continued use of risdiplam for adults with SMA, and may help patients and clinicians to understand and assess treatment options.