Sustained-Release Fampridine for Symptomatic Treatment of Multiple Sclerosis

Abstract

To review the pharmacology, pharmacokinetics, clinical trials, and adverse effects of sustained-release (SR) fampridine in patients with multiple sclerosis (MS). An English-language human data search was done using PubMed/MEDLINE (1966-August 2008) to retrieve relevant material using the search terms fampridine-SR, 4-aminopyridine, and multiple sclerosis. References of selected articles and information from the drug developer were used to further identify pertinent trials. Article selection was based primarily on studies that evaluated the pharmacokinetics, safety, and efficacy of fampridine-SR in patients with MS. Relevant meeting abstracts were also included as part of the analysis. Fampridine-SR is a sustained-release, orally administered potassium-channel blocker acting in the central nervous system to enhance conduction in demyelinated axons. Several small trials have evaluated the safety and efficacy of fampridine-SR in patients with MS to improve their walking ability. Data from a recent large Phase 3 trial indicated that walking speed improved in 42.9% of patients with MS who were treated with fampridine-SR compared with 9.3% of those who received placebo (p < 0.001). Treatment-related adverse events associated with the use of fampridine-SR include dizziness, insomnia, nausea, and paresthesia. More severe adverse events, such as seizure, have occurred in patients receiving doses higher than those currently recommended. Positive results from 2 Phase 3 clinical trials have put fampridine-SR on the path toward approval as a medication for improving walking speed and lower extremity strength in patients with MS.