Multiple Sclerosis Treatments Face Off
Long-Term Study Gives Rebif the Edge Over Avonex
WebMD News Archive
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
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.