European Union regulators rejected the drug Tysabri from
as a treatment for the dangerous gastrointestinal ailment Crohn's disease.
The companies said Thursday they will appeal the decision.
Medical advisers to the European Medicines Agency said there was "insufficient evidence" of Tysabri's effectiveness in treating the chronic inflammatory disease. Tysabri is approved in the U.S., EU and several other markets for certain forms of
The EU medical advisers said they were concerned about dangerous side effects, most notably "a risk of serious infections, including the brain infection
called progressive multifocal leukoencephalopathy," or PML.
Worries about PML caused the companies to
pull Tysabri from all markets in February 2005 as an MS treatment. Tysabri was later reinstated as an MS drug with severe restrictions.
The EU advisers concluded that the benefits of Tysabri for Crohn's didn't outweigh the risks. The companies want it to be prescribed for patients who don't respond well to other Crohn's treatments or who have active gastrointestinal inflammation. The companies' expect a verdict on their appeal during the first quarter of 2008.
Shares of both companies fell on the news. The smaller Elan lost 66 cents, or 3%, to $21.26. Biogen Idec's stock was off 9 cents to $55.09.
Their bid for Tysabri as a U.S. treatment for moderate to severe Crohn's goes before a panel of medical advisers to the Food and Drug Administration on July 31. The FDA isn't bound by the panel's suggestions, but it usually follows them.