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).
The companies' latest study revealed no new cases of PML. This follows an earlier safety evaluation which also found no new reported cases of PML in patients with MS. Three confirmed cases of PML were previously reported, two of which were fatal.
The two companies are trying to get Tysabri back on the market. On September 26, they submitted a license application for Tysabri to the US Food and Drug Administration for the treatment of MS. They also recently submitted a similar data package to the European Medicines Agency.
Elan said that over 1,500 Crohn's and rheumatoid arthritis patients from clinical trials were eligible for the safety evaluation. A total of 88% of these patients participated in the safety evaluation. It said that 98% of the patients participating in the evaluation had a neurological exam by a consultant neurologist and an MRI exam.