Dalfampridine for improving walking dysfunction in HTLV-1-associated myelopathy: a pilot randomized controlled trial

HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a debilitating neurodegenerative condition characterized by progressive motor dysfunction, particularly affecting gait. Currently, there is no established effective treatment for HAM/TSP. Dalfampridine, a potassium channel blocker, has shown efficacy in improving walking speed in patients with multiple sclerosis, but its effects on patients with HAM/TSP remain unclear. This study aims to evaluate the efficacy of Dalfampridine in improving walking speed in patients with HAM/TSP. This pilot randomized controlled study enrolled 40 patients diagnosed with HAM/TSP, who were randomly assigned to either the treatment group ( n = 20) receiving dalfampridine, or the control group ( n = 20). However, five participants withdrew during the study, resulting in a final sample size of 35 participants, 18 in the treatment group and 17 in the control group. Patients were assessed using the 25-Foot Walk Test (25FWT) at baseline, after 30 days, and after 60 days. Statistical analyses included repeated measures ANOVA to evaluate the effects of time, group, and their interaction on walking speed. A significant interaction between time and group (F = 3.314, p < 0.05) indicated that walking speed improved more in the treatment group than in the control group. Post-hoc analysis within the treatment group demonstrated that motor performance improved significantly from baseline to both post-treatment time points. Dalfampridine significantly improved walking speed in HAM/TSP patients, with consistent progress observed over time. Further studies are needed to investigate optimal dosing, long-term efficacy, and patient subgroups who may benefit most from this treatment. This trial was registered at Iranian Registry of Clinical Trials ( http://www.irct.ir ; trial ID: IRCT20180618040127N4) on 2023-06-08.