Side effects associated with interferon beta for multiple sclerosis highlight the need for additional post-market surveillance for approved drugs.
Many patients with multiple sclerosis (MS) are treated with interferon beta to control symptoms and relapses. These drugs inhibit immune system cells and processes to reduce MS-related inflammation.
While nearly all drugs have potential adverse events, a new study published by Neurology has identified new adverse events associated with interferon beta that highlight the need for additional post-market surveillance for approved drugs.
Included in the study were the health records of more than 2000 patients with relapsing-remitting MS from 1995 to 2008.
“Once a drug is released on the market, there are very few ways to systematically monitor adverse events,” said senior study author Helen Tremlett, PhD. “Clinical trials cannot identify all adverse effects of a drug treatment partly due to small sample sizes and relatively short follow-up periods.”
Surprisingly, the authors discovered an increased risk of stroke, migraine, and depression among patients with MS treated with interferon beta. They also found that patients had blood abnormalities, according to the study.
“Beta interferons are generally thought of as having a favourable [sic] safety profile, especially compared to the newer therapies for multiple sclerosis. And that is still the case; our study does not change that,” Dr Tremlett said. “However, very few studies had comprehensively and quantitatively assessed their safety in real world clinical practice. Our findings complement and extend on previous observations.”
Specifically, patients with MS treated with interferon beta had a 1.8-fold increased risk of stroke, a 1.6-fold increased risk of migraine, and a 1.3-fold increased risk of depression and blood abnormalities, according to the study.
The authors also discovered that patients treated with interferon beta for more than 2 years had a decreased risk of bronchitis and upper respiratory infections. Since these infections are common among patients with MS, the drug may be beneficial.
The authors hope their findings will lead to the development of biomarkers that predict patients who are at risk of experiencing the adverse events, according to the study.
“Further advances could enable personalized or precision medicine where patients who are at increased risk of having an adverse reaction can be identified. This could help guide discussions about individual treatment options and considerations,” Dr Tremlett said.
While the authors found an increased risk of potentially serious adverse events, the authors do not suggest patients stop treatment with interferon beta. They caution that their findings are based on population data and that individual risk will vary.
“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” said study co-author Anthony Traboulsee, MD.