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Multiple Sclerosis Treatments Face Off

Long-Term Study Gives Rebif the Edge Over Avonex
WebMD Health News

June 4, 2003 - When it comes to multiple sclerosis treatments, Rebif might have the edge over Avonex, according to a head-to-head comparison of the two drugs.

The study shows that after 63 weeks of multiple sclerosis treatment, 56% of patients on Rebif were free from relapses compared with 48% of those on Avonex.

The findings of the EVIDENCE trial were presented at the annual meeting of the Consortium of Multiple Sclerosis Centers in San Diego.

Rebif and Avonex contain the same active ingredient (interferon beta-1a), but these multiple sclerosis treatments differ in the frequency, dosage, and method in which they are used. Rebif is injected under the skin three times a week at a higher dose, and Avonex is injected once a week directly into the muscle of the thigh, upper arm, or hip at a lower dose.

About 2 million people worldwide suffer from multiple sclerosis, a progressive disease that affects the brain and nervous system. The exact cause of multiple sclerosis is unknown. But most researchers believe multiple sclerosis is caused by an immune system malfunction that leads to brain and spinal cord inflammation -- and symptoms such as a loss of muscle control and vision.

For most people with multiple sclerosis, these symptoms come and go during periodic relapses of their disease. Viruses and other infections are thought to trigger these disease relapses.

How Interferon Helps Multiple Sclerosis

Interferon-based treatments for multiple sclerosis are designed to strengthen the immune system to prevent such relapses and protect the brain and spinal cord from further damage. The interferon drugs closely resemble the body's own natural interferon that is produced by the immune system to defend against infection and disease.

Researchers say the long-term results from this study confirm the advantage of high-dose interferon treatment with Rebif over Avonex. Previous studies had already shown these results after 24 and 48 weeks of multiple sclerosis treatment.

The study found that people with multiple sclerosis who received Rebif were 17% more likely to remain free from relapse than those on Avonex after 63 weeks of treatment. Patients treated with Rebif also showed fewer brain lesions on MRI (magnetic resonance imaging) scans.

These findings show that not only does Rebif have a continued beneficial effect on preventing relapse and changes in MRI scans, but these differences persist, says researcher Hillel Panitch, MD, clinical researcher at the University of Vermont College of Medicine.

Researchers say the presence of brain lesions is thought to be an indicator of the progression of multiple sclerosis and that patients with less brain damage on MRI scans generally fare better than those with extensive lesions.

Weighing the Evidence on Multiple Sclerosis Treatments

Aaron Miller, MD, chief medical officer of the National Multiple Sclerosis Society, says the differences between Rebif and Avonex in preventing disease relapses are small in absolute terms, but they are statistically significant, and that's important to many people with MS.

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