The Effects of Dalfampridine Extended Release on Areas of Motor Function Beyond Walking in Persons with Multiple Sclerosis

Background: Dalfampridine extended release (D-ER), fampridine outside the US, is used to improve walking speed in patients with multiple sclerosis (PwMS). D-ER is a potassium channel blocker that putatively improves neuronal conduction along demyelinated axons. The clinical response to dalfampridine has been variable classifying individuals as responders or non-responders based on walking speed. It is possible that D-ER may have effects on motor areas other than walking.

Objectives: To assess the effect of D-ER treatment in PwMS in treating other clinical aspects beyond walking in a clinical setting.

Methods: PwMS who were newly prescribed D-ER (N=39; 8 M, 31 F, mean age 54.13 + 9.9 yr, disease duration 12.92 + 8.8 yr, EDSS 5.1 + 1.6) were included in this observational study. The following outcomes were assessed prior to first dose and 3.5, 7, 10.5 and 14 weeks post drug: Timed 25 Foot Walk (T25FW), Six Spot Step Test (SSST), 6 Minute Walk (6MW), 9 Hole Peg Test (9HPT), Box and Block Test (BBT), and 12-Item Multiple Sclerosis Walking Scale (MSWS-12). We analyzed outcomes for all subjects combined (All), and by timed walk responder (TWR) and non-responder (TWNR) status, as defined by Goodman et al (2009). Changes from baseline to 14 week follow-up were assessed using paired t-tests or Wilcoxon signed rank test. Data were also analyzed using all time points with linear mixed models or Friedman test; p-value was set at <.05.

Results: The All subjects group and TWRs (n=21; 54%) significantly improved (p<.05) on all outcomes above in pre-post analyses and in linear mixed models over time with the exception of the TWRs mixed model analysis for 9HPT (non-dominant side). TWNRs (n=8; 21%) significantly improved (p<.05) on MSWS-12, SSST (non-dominant side), and BBT (non-dominant side) in the pre-post analyses and improved on the MSWS-12, SSST (both sides), and BBT (both sides) in the mixed model analyses over time.

Conclusions: PwMS newly prescribed D-ER had significant improvements on functional tasks of the upper and lower extremities and self reported outcomes, even among traditional timed walk non-responders.