During clinical trials, people with multiple sclerosis (MS) participate in studies that test new therapies for the disease. The therapies tested in clinical trials have shown promise in laboratory and animal research, but they may not have been shown to be safe and effective for humans yet. Each trial requires that a person meet specific requirements (involving, for example, age, time since diagnosis, and course of MS) in order to ensure that the results will be clear enough to be useful.

Medications being tested in clinical trials pass through three phases:

• Phase I: Testing for safety
• Phase II: Testing for effectiveness against the disease. This phase is usually limited to less than 50 people.
• Phase III: Comparing the medication with a placebo or an already approved therapy. Participants are watched closely for side effects. This phase may involve hundreds of people in several locations.
• Phase IV: Further testing of approved medications

Call the National Multiple Sclerosis Society (1-800-FIGHT-MS, or 1-800-344-4867) or the Brain Resources and Information Network of the National Institute of Neurological Disorders and Stroke (1-800-352-9424) for information on clinical trials. Or visit the National Institutes of Health clinical trials Web site at www.ClinicalTrials.gov. Discuss with your doctor, nurse, or therapist the possibility of participating in a trial. Current clinical trials involve testing new medications, higher doses of existing medications, and combination therapies.