Biogen Idec reports another problem with Tysabri

Biogen Idec Inc. reported today another patient has contracted a potentially deadly brain disease after using Tysabri, the fourth since Biogen Idec brought the multiple sclerosis drug back on the market two and a half years ago.

The Cambridge biotechnology company originally launched Tysabri in 2004, but pulled it from the market just three months later after a handful of patients were diagnosed with progressive multifocal leukoencephalopathy, or PML. Two later died.

Nevertheless, Biogen Idec reintroduced Tysabri with its Irish partner, Elan Corp., in July 2006 with stricter prescribing guidelines - designed to minimize the risk of contracting the disease - a warning that one in 1,000 patients could contract PML and closer monitoring of patients. Since late July, four more patients have been diagnosed with PML, though none has died, spurring hopes that early detection of PML might help better treat the disease.

Though the additional cases of PML has spooked some investors - fanning fears that many doctors will think twice about prescribing the drug - many existing patients have been willing to stick with Tysabri because they believe it remains the best option to treat MS and Crohn's disease when other treatments fail. They also say the incidence of PML remains rare. As of the end of September, more than 35,500 patients were taking Tysabri, including 18,000 who had been taking the drug for more than a year.

The latest patient, who is from Europe, had been taking Tysabri for 26 months and is being treated by the patient's physician.

Biogen Idec shares dipped 1.7 percent on the Nasdaq Stock Market to $46.19 as of 10:30 a.m, on par with the overall decline of the market. JP Morgan & Co. analyst Geoff Meacham said the latest news wasn’t surprising, since the drug label warns that 1 in 1,000 patients may contract the disease, and shouldn’t further hurt the stock.

“Investors are becoming increasingly comfortable with the PML risk, which, in our view, bodes quite well for BIIB shares,’’ Meacham wrote in a note to investors.

Still, the stock had traded above $70 per share in July, before Biogen Idec reported the new cases of PML.
(By Todd Wallack, Globe staff)