By ACCORDANT HEALTH SERVICES
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 exacerbations (also called relapses or flare-ups). Other drugs help slow the progression of the disease.
It is now known that MS damages nerve fibers located beneath myelin that is undergoing destruction. 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.
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. Other drugs may be used for specific symptoms and are discussed in other articles.
Interferons are immune 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 exacerbations, 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 the 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 exacerbations for relapsing-remitting patients. MRI scans have also shown that Betaseron lessens the increase in 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 exacerbations. Avonex is taken once a week as an intramuscular injection. A recent study shows that it is beneficial to begin Avonex after the first demyelinating event, 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 fewer 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 exacerbations.
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 exacerbations, and it has also been found to reduce new brain lesions. It is thought that Copaxone stimulates the production of certain cytokines, which affect autoimmune activity and protect the myelin surrounding the nerve fibers. Copaxone is taken every day as a subcutaneous injection.
Novantrone (mitoxantrone) 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 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 into a vein for 5-15 minutes every three months.
There is a risk of heart damage with Novantrone. Doctors test the heart before the first dose, throughout treatment, and after Novantrone is stopped. There is a limit to how much Novantrone can be taken during a person's lifetime. Most patients reach this limit after 8-12 doses over a 2-3 year period. You and your doctor should both keep track of how much Novantrone you get.
Tysabri (natalizumab) was first approved by the FDA in 2004. It is believed to prevent potentially damaging immune cells from reaching the central nervous system. In February of 2005 natalizumab was voluntarily withdrawn from the market because of a viral brain infection called progressive multifocal leukoencephalopathy, or PML. This usually fatal infection occurred in three patients (two MS and one Crohn's disease) who were also taking other drugs that affect the immune system.
Natalizumab was reapproved by the FDA in 2006 monotherapy for patients with relapsing forms of MS, and two more cases of PML were reported in 2008. It is used in patients who do not respond to medicines like interferons. Natalizumab is available only under a restricted TOUCH™ Prescribing Program with strict guidelines and strong warnings to potential recipients. This drug is infused into a vein every four weeks.
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.
Azathioprine is a useful treatment for people who have many relapses and need steroids. This drug also has its unwanted side effects, so the lifetime dose must be closely watched.
Last Modified Date: March 01, 2009 © Accordant Health Services, a CVS/Caremark company. All rights reserved.
This article has been reviewed for accuracy by a member of the Accordant Health Services Medical Advisory Team.
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