In several cases, the patient or corpse was allegedly diagnosed with Progressive Multifocal Leukoencephalopathy (PML), a rare brain infection that directly affects the central nervous system. Symptoms of PML are similar to a stroke: headaches, memory loss, speech and vision difficulties, limb weakness, and partial paralysis; the disease leads to coma then to death.
To date, approximately 8,000 patients have been involved in clinical trials or prescribed Tysabri for multiple sclerosis, Crohn's disease and rheumatoid arthritis. It is alleged that many patients with MS were persuaded to participate in these drug trials even if their symptoms were minimal and they did not need the drug.
Biogen Idec and Elan Pharmaceuticals hope to redistribute the drug after extensive evaluations of Tysabri and the possible link to the deadly infection, PML. Other known side effects of Tysabri include depression, urinary tract infection, lower respiratory infection, joint pain, fatigue, and headache.
The billion-dollar company, Biogen Idec, based in Cambridge, Massachusetts, also has another MS drug in the news: the bread-winning drug, Avonex, the most widely prescribed Multiple Sclerosis drug in the world with revenues of $1.4 billion in 2004 has recently been linked to increased risk of liver damage and liver failure.
Tysabri In the NewsFDA votes to re-release Tysabri despite concern over rare, but deadly, side effects. If regulators move forward with this decision, Tysabri will be the second prescription drug in history to return to the shelves after a major drug recall. Surprisingly regulators are aware that this may result in additional MS patient deaths - one out of 1,000 patients may develop PML. A black-box warning may be added to the drug's label. (Mar-08-06) [MARKET WATCH]
The risk of a rare brain disease and other infections remains the primary concern of federal regulators as they seek independent advice on whether to allow a promising multiple sclerosis drug back on the market. (Mar-06-06) [MIAMI HERALD]
Biogen Idec Inc.'s multiple sclerosis drug Tysabri produced signs of fatal nerve disease. On February 28th the drug was withdrawn from the market after three fatal cases from progressive multifocal leukoencephalopathy. The U.S. Food and Drug Administration disclosed a possible fourth fatal case in the first week of June. (June-09-05) [BLOOMBERG]
FDA's Public Health Advisory for Tysabri