MS drug may slow progress of disease
Almost 10 years ago, people with multiple sclerosis were heartened by the approval of the first medication to slow progression of the disease. Since then, four more prescription drugs have reached the marketplace. But the best may be yet to come.
The new drug, Antegren, which works differently than existing treatments, also may be more effective. Over the next two years, it will be tested in two studies involving more than 2,000 patients.
“None of the agents approved by the FDA seem to have effects this prominent -- and prominent in a relatively short time,†said Dr. J. Theodore Phillips, a Dallas neurologist who is helping conduct the studies.
Multiple sclerosis affects the nerves of the eyes, brain and spinal cord, causing the nerves to lose patches of myelin, the protective sheath that allows electrical impulses to be carried along nerve fibers. When myelin is destroyed, scar tissue called plaques forms. These lesions can appear in multiple places within the central nervous system and cause blurred vision, numbness, jerkiness of limbs, loss of balance and fatigue.
Research over the last 15 years has revealed that myelin is destroyed when certain white cells (cells that attack infection) gain access to the brain and spinal cord. Once within that tissue, these white cells cause inflammation that eventually leaves the scar tissue, Phillips said.
“One of the key steps in the development of multiple sclerosis is the entrance into the brain or spinal cord of these problematic white blood cells,†he said. “Antegren blocks that important, fundamental step of crossing that blood-brain barrier.â€
Antegren, which is being developed by Elan Corp. and Biogen Inc., is not a cure for multiple sclerosis. Like existing medications, it only slows progression of the disease. But an earlier study of 213 people boosted hopes for Antegren’s effectiveness. In that study, Antegren reduced the number of new lesions by 85% to 95% (detected by magnetic resonance imaging) and relapses by 45% to 75%. Antegren is given in monthly infusions; most study subjects improved after the first infusion.
Existing therapies, which aim to calm the inflammation in the nerves, typically improve relapse rates by about 30%, said Phillips.
So far, Antegren appears safe, with side effects limited to mild allergic reactions, skin rashes and fever. But the new round of research will be crucial to defining the drug’s true potential and whether its side effects are minimal, said Dr. Stephen Reingold, vice president of research programs for the National Multiple Sclerosis Society.
“It’s a whole new mode of action, and that’s a good thing,†Reingold said. But, he added, “the [previous] study was very short, six months, and a small study. Obviously, you can’t say for sure how well it will work.â€
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MS at a glance
It affects about 400,000 Americans.
It affects twice as many women as men.
Typically, onset occurs between the ages of 20 and 50.
It occurs more in people of Northern European ancestry, but other ethnicities are not immune.
Symptoms vary greatly among individuals. There are four types of MS, which are diagnosed based on the frequency and severity of symptoms.
It is not fatal. Two-thirds of people with the disorder are able to walk, although many need aid.
Its cause is unknown.
It is difficult to diagnose because symptoms can come and go. There is no single test to prove or rule out MS. Magnetic resonance imaging can help produce a diagnosis by showing the presence of plaques.
