MedWatch Alert Warns About Liver Risks of Biogen's MS Drug Avonex

March 22, 2005

Biogen Idec's multiple sclerosis (MS) drug Avonex can cause severe liver damage, including liver failure, according to a MedWatch alert released by the FDA.

"Severe hepatic injury, including cases of hepatic failure, has been reported in patients taking Avonex [interferon beta-1a]," the FDA said. "The potential risk of Avonex used in combination with known hepatotoxic drugs or other products (e.g. alcohol) should be considered prior to Avonex administration, or when adding new agents to the regimen of patients already on Avonex."

The alert was issued in conjunction with new Avonex labeling, the details of which were included in a "Dear Healthcare Professional" letter disseminated by Biogen. Avonex's labeling now includes information on hepatic injury in the "Warnings," "Precautions" and "Adverse Reactions" sections.

The MedWatch alert was issued just two weeks after Biogen was forced to remove another of its MS drugs -- Tysabri (natalizumab) -- from the market because of safety concerns.

For more information on Avonex, go to http://www.fda.gov/medwatch/SAFETY/2005/safety05.htm#Avonex (http://www.fda.gov/medwatch/SAFETY/2005/safety05.htm#Avonex).