Sep. 24, 2002
There is no longer any doubt that neutralizing antibodies jeopardize the long-term beneficial effects of beta interferons in Multiple Sclerosis (MS), say researchers at the joint A/ECTRIMS congress (American and European Congresses on Treatment and Research In Multiple Sclerosis) held in Baltimore, Maryland last week.
As with other injectable protein therapies that are used to treat a variety of conditions, patients with MS can develop antibodies in response to beta interferon therapy. One type of antibodies, called neutralizing antibodies, can seriously impact the effectiveness of interferon therapy for some people with MS.
Interferons are proteins produced naturally in the body which regulate the immune system. They can be artificially manufactured through genetic engineering, then administered to patients in order to treat MS. However, some people's immune systems recognize manufactured interferon as foreign matter and hence generate antibodies against it. These antibodies can then attach themselves to administered interferon in the bloodstream, thereby "neutralizing" its effect. This may seriously diminish the beneficial effects of the therapy, resulting in an increased number of MS attacks or relapses.
Several recent clinical trials have measured the amount of neutralizing antibodies that develop against interferons, as well as the short-term and long-term effects of these treatments.
In one such study presented at A/ECTRIMS, headed by Professor Per Soelberg Sorensen of Copenhagen, Denmark, the research team studied 467 consecutive relapsing-remitting MS patients (who were initiated on beta interferon therapy between 1996 and 1998) measuring neutralizing antibody levels every six months for up to four years.
Results showed that the presence of neutralizing antibodies significantly increased the number of MS attacks, and sped up the time to first attack, which occurred an average of 177 days earlier than in patients with no neutralizing antibodies.
"Our study is just the latest in a growing body of evidence for the clinical significance of neutralizing antibodies. There is already a wealth of published data showing a strong impact of neutralizing antibodies on clinical, MRI and biological efficacy of beta interferons in MS," says Dr. Sorensen.
"This information is important for the 50,000 Canadians who suffer from MS," says Dr. George Rice, neurologist and Director of the MS Clinic at London Health Sciences in London, ON. "When we choose a beta interferon treatment, we have many criteria to consider. But in my mind, one of the most important is the rate of neutralizing antibodies since they can significantly weaken the long-term clinical efficacy of these therapies for patients with MS," he adds.
Previous clinical trial data has shown that Avonex(R) (interferon beta-1a administered once weekly) consistently produces the lowest amount of neutralizing antibodies among the available beta interferons. At a separate symposium at the A/ECTRIMS meeting, Dr. Sorensen confirmed this finding by showing that in his study, 76% of Rebif(R) patients developed neutralizing antibodies, versus 33% of Betaseron(R) patients and only 11% of Avonex(R) patients, after three years of treatment.
Multiple sclerosis is the most common neurological condition affecting young adults in Canada. MS most often strikes young adults - women and men between 20 and 40 who are in their productive family and career years. Women develop MS almost twice as often as men.
The research and development activities of Biogen, the manufacturer of Avonex, are focused on novel products for multiple sclerosis, inflammatory, respiratory, kidney and cardiovascular diseases and in developmental biology and gene therapy.
For more information on Multiple Sclerosis and its treatment, you may visit http://www.msalliance.com or call 1-877-MS INFO5 (1-877-674-6365).
Avonex(R) is a registered trademark of Biogen Inc., Betaseron(R) is a registered trademark of Berlex Canada Inc., and Rebif(R) is a registered trademark of Serono.
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