Tysabri Recalled From the Market in Early 2005 Due to PML, a Fatal Brain Condition

Biogen Idec Inc. and Elan Corp., the makers of the multiple sclerosis ("MS") drug Tysabri, filed papers with the FDA on September 26, 2005 requesting permission to resume selling the drug.  Tysabri had been withdrawn from the U.S. market in February 2005 when a patient developed progressive multifocal leukoencephalopathy ("PML"), a rare and often fatal brain disorder, after taking Tysabri with Avonex, Biogen Idec’s older MS treatment.

The companies’ filing of a proposed new warning label for Tysabri and new safety data from recent clinical trials triggers the FDA review process to get the Tysabri back on the market. In addition, the drug companies asked the FDA for an expedited review of their Tysabri application; if the expedited review request is granted, a decision would be issued by the FDA in about six months, as opposed to the standard ten-month review.

Commenting on why the companies did not make available to the press nor the public their proposed language for the revised Tysabri warning label, Biogen Idec spokeswoman Amy Brockelman said such disclosure would be premature insofar that the FDA has not started their review of this new Tysabri application.

Biogen Idec and Elan also filed a proposed risk-management plan for dealing with the possible threat of PML, the serious brain disorder linked to Tysabri earlier this year.  In announcing this new Tysabri application to the FDA, Biogen Idec’s Brockelman told reporters that proposed risk-management plan would include the creation of a registry of all patients who take Tysabri.

While the companies would not disclose any more of the details concerning their new Tysabri application, observers believe that the drug companies are likely to stress to the FDA the fact that there have been no reports of PML in patients who took Tysabri alone, i.e., monotherapy, as opposed to taking Tysabri in combination with other MS drugs such as Avonex.  Along these lines, it is known that the new Tysabri application submitted to the FDA included data from a safety review completed in early August 2005 involving more than 2,000 MS patients who took only Tysabri in clinical trials. Significantly, there were no new cases of PML discovered in that safety review done by Biogen Idec and Elan.

(Posted by: Tom Lamb)