Tysabri Information

  On February 28, 2005, biotechnology companies Biogen and
Elan suspended sales of the multiple sclerosis drug Tysabri® after
one patient was diagnosed and later died from the rare
neurological disease progressive multifocal leukoencephalopathy,
and a second was suspected of contracting it. Both patients had
been using Tysabri® in combination with an earlier Biogen Idec MS
drug, Avonex®.

    In addition to the suspension of sales, Biogen and Elan have
recommended doctors cease prescriptions immediately and have
halted all marketing efforts. The decision came from both
companies after consulting with the FDA.

    Tysabri®, which also goes by the generic name natalizumab,
was designed to slow the progression of disabilities relating to
multiple sclerosis. Further studies showed it could also help with
the gastrointestinal ailment Chron's Disease as well as
rheumatoid arthritis.

    Since the FDA approved Tysabri® in November, approximately
5,000 patients received intravenous infusions. An additional 3,000
patients received Tysabri® in clinical trials.