The various multiple sclerosis (MS) symptoms, such as fatigue or optic neuritis, are treated with medications that help relieve or eliminate discomfort. These medications, however, do not treat the cause of the symptoms, which is the underlying disease of the disease. Medication aimed at altering the course of the disease itself is called disease-modifying therapy. The main drugs used to modify MS are the "ABC drugs": Avonex®, Betaseron®, Copaxone® and Rebif®. Many patients take drugs for their symptoms at the same time they are taking one of the ABC-R drugs.

Each of the ABC-R drugs is an immunomodulator: a drug that has the ability to alter the body's. Avonex, Rebif, and Betaseron affect the body's entire immune system. Copaxone apparently affects the immune system responses that are related to myelin.

The ABC-R drugs slow the progression of some forms of MS and improve the quality of life for people with the disease. Slowing the progress of the disease is extremely important because damage to nerve fibers becomes cumulative over time, resulting in permanent disability. There is also evidence that damage to brain tissue occurs even before patients experience any symptoms. Therefore, the Medical Advisory Board of the National Multiple Sclerosis Society recommends early aggressive treatment with one of the ABC-R drugs. This means starting therapy as soon possible after a definite diagnosis of relapsing-remitting MS.

Avonex®, Rebif® and Betaseron® are beta interferons. Interferons are proteins that occur naturally in the human body; they were so named because they "interfere" with viral infections. Interferons are now known to also have a wider role in the immune system, and can fight diseases such as hepatitis and some cancers. They are used to treat MS because they help regulate the immune system to block some of its attacks on myelin.

Avonex (beta interferon-1a), Rebif (beta interferon-1a) and Betaseron (beta interferon-1b) are manufactured using recombinant technology, also known as genetic engineering. Because the genetic code is universal, both bacteria and mammalian cells can "read" the instructions for making interferon that are contained in human genes. Avonex and Rebif are made by placing a human gene into hamster cells. Betaseron is made by placing a slightly modified human gene into E-coli bacteria. Interferon is manufactured in these "hosts" just as if were their own protein.

Betaseron was approved the Food and Drug Administration In 1993. It was the first drug capable of decreasing the frequency of flare-ups for relapse-remitting patients. In 1996 the FDA approved Avonex for treating relapsing-remitting patients. Rebif received FDA approval in 2002. These medications reduce the frequency of relapses and prevent new plaques from forming in the brain and slow the progression of physical disability . Patients who use these drugs still experience flare-ups, but they occur less often, don't last as long, and are less severe. These drugs are currently used for relapsing-remitting MS.

Copaxone® is not an interferon, and is unlike any other drug. Copaxone, also called glatiramer acetate, is a man-made mixture of proteins with a molecular structure that resembles myelin. While it is not entirely clear why or how Copaxone works, it is thought that this drug may activate white blood cells that are anti-inflammatory. It appears to suppress immune responses without damaging myelin. It also seems to slow disease progression.

Administration

Avonex: Once a week in an intramuscular (into the muscle) injection.

Betaseron: Every other day in subcutaneous (under the skin) injections.

Copaxone: Daily in a subcutaneous injection.

Rebif: Subcutaneous injection three times per week

Lab Testing to Monitor Patient's Health Status

Avonex: CBC (complete blood count), differential blood counts, platelets and liver function tests (LFT's) every 3 months

Betaseron: CBC, differential blood counts, platelets and LFT’s every 3 months.

Copaxone: None

Rebif: CBC, differential blood counts, platelets and LFT's at 1 and 3 months, and then every 3 months

Common Side Effects

Avonex: Flu-like symptoms (such as fever, chills, sweating, muscle pain, malaise, nausea, headaches), .mild anemia, sun sensitivity, depression, injection site reactions (inflammation, pain, discoloration).

Betaseron: Flu-like symptoms (such as fever, chills, sweating, muscle pain, malaise, nausea, headaches), injection site reactions, ) shortness of breath, menstrual problems, depression.

Copaxone: Injection site reactions, chest pain, nausea, weakness. On rare occasions, patients experience a systemic reaction within minutes of the injection consisting of chest tightness and facial flushing, sometimes accompanied by palpitations, shortness of breath, and/or a feeling of anxiety. The reaction is self-limiting, usually within 10 to 20 minutes and has never been shown to be serious

Rebif: Flu-like symptoms (such as fever, chills, sweating, muscle pain, malaise, nausea, headaches), injection site reactions, depression

References

First published October 1, 1999
Last updated May 3, 2003
Copyright © 1999 Accordant Health Services, Inc. All Rights Reserved.

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