SX12
Effect of Dalfampridine on Subjective Domains of Functioning in Patients with Multiple Sclerosis
Dalfampridine is an FDA approved medication to improve walking speed in patients with multiple sclerosis (MS). Initial studies indicate that some patients can be classified as responders. Responders are defined by an initial walking speed of 8-45 seconds and >=20% improvement in walking speed on dalfampridine. Based on this definition, studies suggest that 25-33% of patients are responders. In addition to improvements in walking speed, some studies suggest that there may be other benefits in patient functioning that are not easily quantifiable.
Objectives:
To determine if dalfampridine treatment in patients with multiple sclerosis provides benefit in subjective domains of functioning in patients who are not classified as responders in a Timed 25-foot Walk (T25FW).
Methods:
IRB approval was requested and granted to perform a retrospective chart review of all individuals started on dalfampridine between March 2009 and September 2011 at an academic institution in order to determine: 1) objective improvement of walk time; and 2) participants’ subjective improvements in functioning. Individuals’ walk times were recorded at both baseline and at follow up subsequent to starting treatment with dalfampridine. During follow up appointments, responses on perceived benefit were categorized into the following categories: stability, stamina, speed, strength, upper extremity functioning, transfers, or other, in order to determine whether the individual subjectively felt an improvement in functioning while taking dalfampridine. Demographic information such as duration of MS diagnosis, length of time on dalfampridine, and EDSS were also extracted from participant charts.
Results:
Of the 92 participants who met inclusion criteria, 15 of 56 (26.8%) who had an initial walking speed of 8-45 seconds had >=20% improvement in walking speed at follow up. Additionally, 3 of 12 individuals with an initial walking speed faster than 8 seconds and 1 of 5 individuals with an initial walking speed slower than 45 seconds also improved by >=20%. Furthermore, 3 individuals who did not walk initially were able to walk at follow up. None of 15 (0%) walking speed responders subjectively felt they responded in other domains of functioning. 21 of 73 (28.8%) ambulatory participants felt they responded most prominently in domains of functioning including stamina and stability. 9 of 19 (47.4%) non-ambulatory participants felt they responded most prominently in domains of functioning including stamina, stability, and upper extremity functioning.
Conclusions:
In a retrospective chart review of 92 individuals started on dalfampridine, 26.8% met the traditional definition of a responder, which is similar to prior studies estimating a 25-33% response rate. There may also be a subset of patients who have a subjective response to dalfampridine, and additional studies should focus on evaluating these individuals.