A cure for multiple sclerosis (MS) has not been found yet. However, aggressive ongoing research has already produced effective drug therapies for treating the underlying disease and for managing symptoms. MS patients now benefit from drugs that can reduce both the severity and frequency of relapses or flare-ups (also called exacerbations).

Other drugs help slow the progression of the disease. It is now known that MS damages nerve fibers by destroying their protective coating, known as myelin. Because the damage inflicted upon the nerves is permanent, it is now recommended that patients seek treatment as soon as they are diagnosed with MS. About 10 percent of patients with MS, however, have such minor symptoms that they do not need any treatment. These patients have benign MS. Unfortunately there is no way to tell for sure who will have benign disease.

To date, MS research has focused on three main goals: preventing or slowing the destruction of myelin; minimizing patients' symptoms; and restoring myelin that has already been damaged or destroyed. The drugs currently prescribed for MS have resulted from research in the first two areas.

Drugs that help slow the overall disease are overviewed in this article. Please see "The ABC Drugs for Multiple Sclerosis" for more detailed information about the disease-modifying drugs.

Interferons are antiviral proteins created naturally by the body. Whenever a virus attacks the body, the body defends itself against the attack by creating beta interferons, which help prevent the multiplication of viruses. Interferons also help regulate the immune system. Avonex®, Betaseron® and Rebif® are genetically modified beta interferons, manufactured through recombinant DNA technology. They are immune-modifying drugs. Patients who use these drugs still experience flare-ups, but they occur less often, don't last as long, and are less severe. It is believed that these drugs are effective against MS because they help regulate the immune system to decrease attacks on myelin.

Betaseron (Interferon beta-1b) was approved by the Food and Drug Administration In 1993. It was the first drug capable of decreasing the frequency of flare-ups for relapsing-remitting patients. MRI scans have also shown that Betaseron decreases the volume of brain lesions and helps keep new lesions from forming. Betaseron is taken by subcutaneous (under the skin) injection every other day.

In 1996 the FDA approved Avonex (Interferon beta-1a) for treating relapsing-remitting patients. Avonex has been proven to slow the progression of relapsing MS and to reduce the frequency of flare-ups. Avonex is taken once a week in an intramuscular injection. A recent study shows that it is beneficial to begin Avonex after the first discovery that nerve fibers are being demyelinated, or stripped of their protective coating -- even prior to a diagnosis of clinically definite MS. In the study, patients who received Avonex had a reduction in the volume of their existing brain lesions, and compared to a placebo group, developed few new lesions.

Rebif, another form of Interferon beta-1a, received FDA approval in 2002 for treating relapsing forms of MS. Rebif is given as a subcutaneous injection three times a week. Like Avonex, Rebif has been proven to slow the progression of relapsing MS and to reduce the frequency of flare-ups.

In 1996 the Food and Drug Administration also approved a non-interferon drug for the treatment of relapsing-remitting MS. Copaxone®, (glatiramer acetate) is as effective as the interferons in curbing flare-ups, and it has also been found to reduce new brain lesions. It is thought that Copaxone works by acting as a "decoy" that diverts autoimmune responses that would otherwise target the myelin that coats nerve cells for destruction. Copaxone produces cytokines, which affect autoimmune activity and protect the myelin surrounding the nerve fibers. Copaxone is taken every day as a subcutaneous injection.

Avonex, Betaseron, Copaxone ("the ABC drugs") and Rebif are disease-modifying agents. Each has been approved for use only for relapsing-remitting MS. These drugs slow the progression of MS and improve quality of life for people with the disease. The Medical Advisory Board of the National Multiple Sclerosis Society recommends early treatment with one of the ABC-R drugs. This means starting therapy as soon as possible after a definite diagnosis of relapsing-remitting MS.

Novantrone®. Novantrone is the first drug approved by the Food and Drug Administration for secondary-progressive MS. It is also approved for progressive-relapsing or worsening relapsing-remitting MS. Novantrone (mitoxantrone) received FDA approval on October 13, 2000. Novantrone is a type of chemotherapy. Clinical trials have shown that Novantrone reduces the number of relapses and decreases the progression of MS in advanced cases. This drug is infused intravenously for 5 to 15 minutes every three months.

Corticosteroids. Corticosteroids reduce inflammation. They may also suppress the immune system's attack on myelin and improve the conduction of nerve impulses. These drugs are effective in relieving symptoms during a severe attack, but they have no long-term value. They also cause a number of side effects when used for long periods. For these reasons doctors limit the use of corticosteroids to instances where they are really needed.

Other Treatments. Chemotherapy seems like a logical treatment for MS because it suppresses the white blood cells that attack myelin. However, when chemotherapy drugs (other than Novantrone) have been used to treat MS in clinical trials, results have been mixed. Side effects vary too, and are sometimes severe. At this point, chemotherapy is a controversial MS treatment.

Another somewhat controversial treatment is plasmapheresis. Plasmapheresis, which means "plasma separation," is also called plasma exchange. This procedure exchanges a patient's blood plasma (the watery part of blood) with a replacement solution. Blood is withdrawn so that the plasma can be separated from the blood cells. Once separated, the blood cells are recombined with a replacement solution that resembles plasma, and the new mixture is then transfused back into the patient. It is thought that plasma exchange may dilute the immune factors in the blood that contribute to MS. Plasma exchange is not recommended for most patients. At this time, it is performed only on patients whose MS results in severe attacks that are unresponsive to other treatments. Researchers don't know why this procedure works for some people and not for others.

References

First published October 1, 1999
Last updated May 2, 2003
Copyright © 1999 Accordant Health Services, Inc. All Rights Reserved.

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