Elan shares surge on latest Tysabri report

Shares in Elan surged nearly 9% this morning after the company said that a new safety evaluation of its Tysabri drug on patients with Crohn's disease and rheumatoid arthritis showed no new cases of a potentially fatal brain disorder.

Elan and Biogen Idec were forced to withdraw the drug last February after some patients using it developed a potentially fatal brain disease, progressive multifocal leukoencephalopathy (PML).