Nusinersen Treatment Had Positive Effect in Patients With SMA

Positve improvement in walking time was seen in patients with spinal muscular atrophy (SMA) who received nusinersen treatment, according to a study published in Journal of Neuromuscular Diseases. Improvement was found in pediatric and adult patients.

SMA is a neuromuscular disease that leads to the degeneration of muscle strength. There are 3 treatments currently available for SMA, including nusinersen, which has proven to improve motor functions in pediatric patients. This study reported the data collected on patients who were treated with nusinersen after an ambulatory visit, with a follow-up of up to 38 months.

This study used data from the SMArtCARE registry that contains data from 58 centers in Germany, Austria, and Switzerland. All centers included in the registry were asked to participate. Patients were included if they had confirmed SMA and received consent from their caregiver. All data were collected from patient visits, and these visits were scheduled every 4 months after the dosing phase.

Patients who were able to walk independently at the start of treatment and patients with documented motor function and baseline characteristics before the start of treatment were included in this study (N = 231). They were then split into 2 groups: pediatric walkers, which included patients younger than 18 years, and adult walkers, which included all patients older than 18 years. Adult walkers had a significantly higher age at symptom onset compared with pediatric walkers. The groups were otherwise comparable.

The researchers were looking for the primary outcome of changes in walking distance, measured using the 6 Minute Walk Test (6MWT). A clinically meaningful difference was a difference of at least 30 m in walking distance.

The 6MWT distance of both adult and pediatric walkers improved during the observation period. Walking distance changed by 39.3 m in pediatric walkers and 24.4 m in adult walkers from baseline to month 38. In addition, the mean walking distance changed by 83 m in pediatric walkers and 46 m in adult walkers when only considering those who performed the 6MWT at both baseline and month 38. Clinically meaningful improvements of at least 30 m was found in 27.2% of the pediatric walkers and 26.5% of the adult walkers.

There were 5 (4.3%) adult walkers who saw at least a 30-m decline in walking distance and 2 (1.8%) pediatric walkers who were not able to walk unassisted after treatment with nusinersen. However, improvements in the 6MWT of at least 30 m were seen in 19.4% of pediatric walkers and 21.1% of adult walkers in the first 14 months of treatment. Only 4.9% of pediatric patients and 7.3% of adult patients declined in ability.

Improvements of 30 m or more were less frequent between month 14 and month 26 (13.1% in pediatrics and 9.9% in adults) and between month 26 and month 38 (12.7% and 5.5%, respectively).

There are some limitations to this study. The real-world data approach made it so that data items and physiotherapeutic assessments were not mandatory, which made all data unavailable for all time points included in the study.

The researchers concluded that the data supports the continued use of nusinersen for patients with a diagnosis of SMA, as improvements in motor function, specifically walking, was seen with continued use of the treatment.

Reference

Pechmann A, Behrens M, Dornbrack K, et al. Improvements in walking distance during nusinersen treatment – a prospective 3-year SMArtCARE registry study. J Neuromuscul Dis. 2022;10(1):29-40. doi:10.3233/JND-221600