Safety and Efficacy Study of Oral Fampridine-SR in Patients With Multiple Sclerosis

Double-Blind, Placebo-Controlled, 20-Week, Parallel Group Study to Evaluate Safety, Tolerability and Activity of Oral Fampridine-SR in Subjects With Multiple Sclerosis

Multiple Sclerosis (MS) is a disorder of the body's immune system that affects the Central Nervous System (CNS). Normally, nerve fibers carry electrical impulses through the spinal cord, providing communication between the brain and the arms and legs. In people with MS, the fatty sheath that surrounds and insulates the nerve fibers (called "myelin") deteriorates, causing nerve impulses to be slowed or stopped. As a result patients with MS may experience periods of muscle weakness and other symptoms such as numbness, loss of vision, loss of coordination, paralysis, spasticity, mental and physical fatigue and a decrease in the ability to think and/or remember. These periods of illness may come (exacerbations) and go (remissions). Fampridine-SR (Sustained Release, SR) is an experimental drug that increases the ability of the nerve to conduct electrical impulses. This study will evaluate the effects of Fampridine-SR on the walking ability of subjects with MS, as well as to examine the effects on muscle strength and spasticity. The study will also examine the possible risks of taking Fampridine-SR.

10 mg twice daily for 1 week 15 mg twice daily for 14 weeks 2 week up titration (10 mg x 1 week, 15 mg x 1 week) 12 weeks stable dose (15 mg) 1 week down titration (10 mg)

2 week up titration (10 mg x 1 week, 15 mg x 1 week) 12 weeks stable dose (20 mg) 1 week down titration (15 mg x 3 days, 10 mg x 4 days)

The primary efficacy variable was the percent change from baseline in average walking speed measured using the Timed 25-Foot Walk Test during the 12-week stable dose period (the average of Study Days 56, 84, and 112), relative to the mean at baseline (placebo run-in period, the average of Study Days 7 and 14).

INCLUSION CRITERIA: Have a confirmed diagnosis of Multiple Sclerosis Are able to walk with or without an assisted device EXCLUSION CRITERIA: Pregnancy, breastfeeding or females of childbearing potential not using adequate birth control Participating in other investigational drug trials A medical history or clinical findings that preclude entry into the study A medication history that precludes entry into the study Previously treated with 4-aminopyridine (4-AP)