Primary Outcome Measures:
- Timed 25 Foot Walk [ Time Frame: Screening visit, visit 4, every 12 weeks thereafter, Last Regular Visit, Follow Up Visit and Early Termination Visit ] [ Designated as safety issue: No ]
Secondary Outcome Measures:
- Clinician Global Impression of Change [ Time Frame: visit 1 and every clinic visit ] [ Designated as safety issue: No ]
- Subject Global Impression [ Time Frame: visit 1 and every clinic visit ] [ Designated as safety issue: No ]
- Expanded Disability Status Scale [ Time Frame: Screening visit, visit 6 and every 24 months thereafter ] [ Designated as safety issue: No ]
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.