Biogen, Elan Given OK for Use of MS Drug

By MARK JEWELL

BOSTON – The makers of a multiple sclerosis medication withdrawn from the market over safety concerns said Wednesday that federal regulators had agreed to let them resume clinical trials of the drug Tysabri.

The drug’s makers, Biogen Idec Inc. and Elan Corp. PLC, expect to hear back from the Food and Drug Administration by late next month on an application they submitted last September to resume marketing Tysabri with a revised label and a plan to address patient risks.

Cambridge-based Biogen Idec and Elan, of Ireland, said they expect in coming weeks to begin an extension of a trial study of Tysabri that the companies halted last February, at the same time that they withdrew the drug from the market. Patients who previously took part in a final phase of the study will be eligible to return to it.

Shares of Biogen Idec, which was to report fourth-quarter and full-year earnings after markets closed Wednesday, rose $1.58, or 3.6 percent, to $45.96 in afternoon trading on the Nasdaq, while U.S. shares of Elan gained 63 cents, or 4.5 percent, to $14.73 on the New York Stock Exchange.

Tysabri was withdrawn Feb. 28, 2005 despite hopes that it would become an important new tool in treating MS, a debilitating and incurable disease in which the body’s immune system attacks, inflames and damages its own nerve tissue.

Biogen Idec shares plunged more than 42 percent the day the drug was withdrawn, while Elan’s stock fell 70 percent.

Biogen Idec has said that if Tysabri returns to the market, the revised label could warn about risks for patients with weak immune systems. Such patients could be more susceptible to contracting a disease called progressive multifocal leukoencephalopathy, or PML.

Biogen Idec and Elan withdrew the drug amid fears that it could heighten the risk of contracting PML. The companies confirmed that two MS patients and one sufferer of Crohn’s disease, an intestinal disorder, had contracted PML. The Crohn’s patient and one of the MS patients died.

After the drug was withdrawn, Biogen Idec and Elan completed safety reviews involving more than 3,000 patients who have taken Tysabri. The companies say no new cases of PML were discovered.