Tysabri is not as good for MSers as it was first thought to be. The Feds are warning doctors that long usage by patients is not beneficial to their well-being. It has been known for years that swelling of the brain that PML causes can be fatal especially to someone who is immune deficient.  Tysabri is marketed by Biogen Idec, Inc. for multiple sclerosis and Crohn's disease.  PML or progressive multifocal leukoencephalopathy increases with continued use of Tysabri and the FDA has confirmed 31 cases since summer of 2006.
Biogen (and Irish drug maker Elan Corp, PLC) have undergone new labeling posts regarding the increased death rates. As of last month, 8 patients have died.

In the new labeling, Food and Drug Administration warns of a complication of PML, i.e. Immune Reconstitution Inflammatory Syndrome that can damage patients' health even after they have stopped taking Tysabri. Shares of Elan dipped 3 cents yesterday ($7.11) while Biogen Idec Inc. fell 4 cents ($53.06).  Too bad, I say. I know of one MSer that was physically devastated when Tysabri was pulled from the market in 2005.  July 2006 it was reintroduced and thousands of people worldwide are now using it in spite of the risks.