Multiple sclerosis is a chronic, usually progressive disease of the central nervous system in which the immune system attacks and destroys the structure, and therefore degrades the function, of nerve cells. Approximately 400,000 Americans have MS, and every week about 200 people are newly diagnosed. Most are between the ages of 20 and 50, and women are affected two to three times as much as men. Worldwide, MS may affect 2.5 million individuals.
According to the National Multiple Sclerosis Society (NMSS), the direct costs of medical care for MS patients in the United States exceed $6 billion annually. Additionally, a recent NMSS analysis estimated the total cost of MS, including medical and non-medical care, production losses, and informal care, at more than $47,000 per U.S. patient per year. Complications from MS may make it harder for people to work and may interfere with their ability to perform common, daily activities.
For most people with MS, the disease slowly progresses with a series of unpredictable flare-ups, also called relapses or exacerbations. But for some, the progression of the disease is rapid. Each relapse tends to lead to increasing disabilities such as walking impairment, muscle weakness or speech or vision impairments. Approximately 80 percent of people with MS experience some form of walking disability. Within 15 years of an MS diagnosis, 50 percent of patients often require assistance walking and in later stages, about a third of patients are unable to walk.
Fampridine-SR is a sustained-release tablet formulation of the investigational drug fampridine (4-aminopyridine, or 4-AP). Data collected in laboratory studies found that fampridine can improve the communication between damaged nerves, which may result in increased neurological function.