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Biogen Reports Seventh PML Case In Tysabri MS Patient


By Thomas Gryta, Of DOW JONES NEWSWIRES

NEW YORK -(Dow Jones)- Biogen Idec Inc. (BIIB) reported that a seventh patient on its multiple sclerosis drug Tysabri, sold with Elan Plc (ELN), has the developed rare brain infection.

A suspected link to progressive multifocal leukoencephalopathy, or PML, led to Tysabri being pulled from the market for 18 months beginning in 2005. Prior to Friday, the company has reported that six people had confirmed cases of PML, with one dying, since the relaunch. The most recent case was reported on April 17.

Shares of Biogen closed Friday down 34 cents at $50.39, while Elan dropped 10 cents, or 1.4%, to $6.94.

The drug was allowed back on the market in 2006 because of its effectiveness in fighting the degenerative disease and the PML incidence remains well below the long-projected risk of one in 1,000 patients developing the infection.

The patient with the latest confirmed PML case took 24 doses of the monthly medication and was located in the U.S. - only the second case of the condition that has been located domestically since the relaunch.

Earlier this year, Biogen retreated from its long-held goal to reach 100,000 patients on Tysabri by the end of 2010. As of the end of March, about 40,000 patients were using Tysabri, up from 37,600 patients at the end of December.

Some believe that duration of therapy plays a role in Tysabri's risk. About 6, 800 patients have used the drug for more than two years, as of the end of March.

Biogen is posting a case update on the Internet every Friday at 4:30 p.m. EST until July 24 - the third anniversary of the drug's relaunch - by which time it expects the risk/benefit profile of Tysabri to be clearer.

Tysabri had 2008 sales of $813 million, but its longer-term sales trajectory, which is key to Biogen's future growth, will depend on the true incidence of PML, which is still coming into focus.

It's going to be difficult to try and determine the "true" incidence of PML because MS patients' reactions to medications is all over the map, just like the unpredictability of the disease itself.

Harry