A new once-a-month intravenous infusion therapy using a monoclonal antibody, offered by the Rush Multiple Sclerosis Center, may reduce relapses for many people with multiple sclerosis.

"We have seen a dramatic two-thirds reduction in relapse rate and a significant decrease in the development of new or enhancing brain MRI lesions, which also point to controlling the disease. I believe this is a major advancement that will benefit patients with MS," said Dr. Dusan Stefoski, a neurologist and Director of the Rush MS Center.

The Food and Drug Administration (FDA) approved the drug, Tysabri, in November 2004, as a treatment for all relapsing forms of MS. Relapses are also known as attacks or exacerbations, and consist of sudden, new or worsening old symptoms of MS. It is now available for general usage to the appropriate MS patients, said Stefoski.

The Rush Multiple Sclerosis Center has been and still is participating in the Phase III clinical research study with Stefoski as the principal investigator.

Tysabri, the first humanized monoclonal antibody approved for the treatment of MS, inhibits adhesion molecules (docking devices) on the surface of immune cells lymphocytes. Research suggests that Tysabri works in MS by preventing immune cells from migrating from the bloodstream into the brain and spinal cord where they cause inflammation and damage myelin insulation on nerve fibers and nerves themselves.

The medication has twice or more the efficacy of the current first line medications for treatment of MS. Patients receive the treatment administered intravenously once monthly over several years in the newly assembled intravenous infusion facility in the Rush MS Center.

According to information from the National Multiple Sclerosis Society, Tysabri reduced the rate of clinical relapses by up to 66% and reduced the development of new or newly enlarging MRI-detected brain lesions by 80% to 92%. A greater proportion of those on therapy remained relapse-free. Tysabri appears to be safe and well tolerated; the most common side effects included headache, fatigue, urinary tract infection, depression, lower respiratory tract infection, joint pain, and abdominal discomfort, and were only a few percentage points more frequent than in the control patients who received placebo. Hives and rash occurred in about 1% of patients, but required discontinuation of Tysabri in only a fraction of those. There is no information available about long-term safety.

MS is a chronic disease of the central nervous system that affects more than 400,000 people in North America and about two million people worldwide. It is more frequent in women than men, with onset typically occurring between 20 and 40 years of age. Symptoms of MS may include vision problems, loss of balance, numbness, difficulty walking and paralysis.

In recognition of the serious nature of MS, the FDA accelerated its review of data from the ongoing Tysabri studies and has determined, based on data from the first year of a two-year study that the drug provided benefit and could be used with relative safety.