FDA Questions Tysabri for Crohn's Disease

Biogen Idec (BIIB) and Elan (ELN) skidded Friday after a Food and Drug Administration report questioned whether the multiple sclerosis drug Tysabri should be used for treating the chronic gastrointestinal ailment Crohn's disease.

The report by FDA staff members said clinical trials show Tysabri's effect isn't "clearly distinguished" from current therapies. The companies are seeking FDA approval to treat Crohn's disease patients for whom other therapies don't work.

The staff report was issued prior to Tuesday's meeting of outside advisers who will make recommendations to the agency. The FDA isn't required to follow its advisers' suggestions, but it usually does so. Staff reports are routinely issued prior to advisory committee meetings.

By early afternoon, shares of Biogen Idec lost $1.30, or 2.2%, to $56.89. The smaller, more volatile Elan dropped 67 cents, or 3.4%, to $19.06 on greater-than-average trading. The stock fell as low as $18.44.

The FDA advisory panel's meeting comes two weeks after European Union health regulators rejected Tysabri as a treatment for Crohn's disease, saying the benefits didn't outweigh the risks.

The companies said they will appeal. Medical advisers to the EU's counterpart to the FDA said there was "insufficient evidence" that Tysabri was effective in treating Crohn's disease. The EU endorses the drug for treating MS.

The FDA staff report says its review of clinical trials shows that Tysabri is less effective in treating Crohn's disease than in treating MS. "The benefit and risk considerations in the Crohn's disease population are considerably different from those in the multiple sclerosis population," the FDA report says.