Study of Oral Fampridine-SR in 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 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 subjects with MS.

Inclusion Criteria:

- Have a confirmed diagnosis of multiple sclerosis

- Are able to walk with or without an assistive 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)