Tofersen treatment leads to sustained stabilization of disease in SOD1 ALS in a “real-world” setting

Objective: Patients with amyotrophic lateral sclerosis (ALS) caused by superoxide dismutase 1 (SOD1) gene mutations (SOD1 ALS) treated with tofersen have shown slowing of disease progression, and disease stabilization with recovery of function in some patients. We report our clinical experience with treating patients with SOD1 ALS and the effects of tofersen on outcome measures. Methods: This was a single-center observational study of patients with SOD1 ALS receiving treatment with tofersen. The effects of tofersen treatment on neurofilament levels, muscle strength, and clinical outcome measures were assessed. Several patients had outpatient neuromuscular rehabilitation in addition to tofersen treatment and we report changes in functional outcomes. Results: Seven SOD1 ALS patients received treatment at our institution. All patients showed robust and sustained declines in serum NfL and CSF pNFH (mean change serum NfL: −57.9%; mean change CSF pNFH: −67.6%). There was apparent disease stabilization as assessed by the ALSFRS-R total score, mean change 1.1 (SD = 0.7). There was notable improvement in functional independence measured by the FIM motor score, mean change 5.13 points (SD = 3.85). Interpretation: This study provides evidence that tofersen treatment in SOD1 ALS can lead to meaningful preservation of function and suggestions of sustained improvement in neurologic function in some patients, and strongly supports the role of neurofilaments as therapeutic biomarkers.