A Randomized Crossover Trial of Dalfampridine Extended Release for Effect on Ambulatory Activity in People with Multiple Sclerosis

Abstract

Dalfampridine extended release (D-ER) is indicated to improve walking in people with multiple sclerosis (MS) as demonstrated by an increase in walking speed. This study assessed the effects of D-ER on accelerometer-based measures in people with MS, including intensity of walking and total amount of walking during daily activities. In this double-blind placebo-controlled crossover study, people with MS-related walking difficulty were randomized (1:1) to receive 4 weeks of D-ER 10 mg twice daily and 4 weeks of placebo in either order separated by a 2-week washout. Participants wore accelerometers for 7 days at baseline and week 3 of each on-drug period. The primary outcome was the peak activity index (PAI), defined as the most intense 30 individual minutes of the day (strides per minute). Secondary outcomes included daily step count, 6-Minute Walk Test (6MWT), Timed Up and Go (TUG) test, and patient-reported outcomes. A mixed-effects repeated-measures statistical model was used. Forty-three participants were randomized (mean Expanded Disability Status Scale score, 5.17). Least squares mean (standard error) change from baseline on the PAI was 0.6 (0.54) strides/min on D-ER and 0.3 (0.55) strides/min on placebo and in daily step count was 148.7 (222.4) on D-ER and 128.0 (225.4) on placebo. Other accelerometer-based measures and the 6MWT showed no significant differences between D-ER and placebo. The TUG test (P = .042) favored D-ER. There were no serious adverse events. Dalfampridine did not show an effect on accelerometer-measured ambulatory activity in people with MS-related walking difficulty. More work is needed to confirm these results.