Open-Label Extension Study to Evaluate the Safety, Tolerability and Activity of Oral Fampridine-SR in Patients With Multiple Sclerosis

Under the original protocol, patients were to have their treatment dose titrated upwards from a starting dose of 10mg b.i.d. to 15mg b.i.d. and then to a stable (maintenance) dose of 20mg b.i.d. The protocol was subsequently revised to lower the maximum maintenance dose. In the most current protocol, all patients were down-titrated to 10mg b.i.d. and maintained at this dose for the greater part of the duration of the study. 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 is an experimental drug that has been reported to possibly improve muscle strength and walking ability for some people with MS. This study will evaluate the effects and possible risks of taking Fampridine-SR in MS patients over a long period of time.