The multiple sclerosis drug Tysabri is no more effective against the bowel disorder Crohn's disease than other approved therapies, US drug reviewers said in documents released today.
Biogen Idec and Elan Corporation are seeking approval to market Tysabri for Crohn's.
US Food and Drug Administration staff said there may be some Crohn's patients for whom Tysabri's risks, which include a rare and serious brain infection, may be more acceptable.
Shares of Biogen Idec fell 1.5 per cent to $57.27 in afternoon trading on Nasdaq. Elan shares fell 3.5 per cent to $19.04 on the New York Stock Exchange.
The FDA will ask a panel of outside advisers on Monday if Tysabri should be approved for Crohn's disease, a use that European regulators recommended against earlier this month.