Vancover, BC—This might come as shocking news to patients opting to stick with their old standby multiple sclerosis (MS) medication because they are worried about side effects with newer agents: A new study has found that beta interferon treatment for relapsing-remitting MS might not be as safe as once assumed.

The report, published in the journal Neurology, analyzed health records of more than 2,000 British Columbians with MS between 1995 and 2008 to reach that conclusion.

“Once a drug is released on the market, there are very few ways to systematically monitor adverse events,” explained senior author Helen Tremlett, PhD, professor in the department of medicine at the Djavad Mowafaghian Centre for Brain Health. “Clinical trials cannot identify all adverse effects of a drug treatment partly due to small sample sizes and relatively short follow-up periods.”

Stroke, migraine, depression, and blood abnormalities all were found with use of beta interferon for MS.

“Beta interferons are generally thought of as having a favorable safety profile, especially compared to the newer therapies for multiple sclerosis. And that is still the case; our study does not change that,” Tremlett emphasized. “However, very few studies had comprehensively and quantitatively assessed their safety in real world clinical practice. Our findings complement and extend on previous observations.”

Among the adverse reactions associated with therapy were:
• A 1.8-fold increased risk of stroke
• A 1.6-fold increased risk of migraine
• A 1.3-fold increased risk of both depression and abnormalities in the blood.

Cautioning that the study was based on population data and was not a randomized, controlled trial, Tremlett said she hopes future research will develop biomarkers to help identify patients who are at the greatest risk of having an adverse event.

“It is important for patients with multiple sclerosis to have ongoing review of the benefits and risks of therapy, and to identify supportive strategies, such as diet and exercise, that could optimize their brain health” added co-author Anthony Traboulsee, MD, associate professor of neurology and director of the MS clinic at UBC.

Even though study authors identified some negative effects, they also uncovered some positive ones. The study found a reduced risk of bronchitis and upper respiratory infections when beta interferon was used for more than 2 years. That’s significant because those infections are common in MS patients.

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