FDA: RISK MANAGEMENT PLAN NECESSARY IF TYSABRI RETURNS TO MARKET
The FDA remains concerned about possible links between Biogen Idec and Elan's multiple-sclerosis (MS) drug Tysabri and progressive multifocal leukoencephalopathy (PML), a rare and deadly nerve disease.
The available data are insufficient to permit a definitive assessment of the risk of PML associated with Tysabri (natalizumab) use, according to an FDA review of the drug released recently in preparation for the agency's Peripheral and Central Nervous System Drugs Advisory Committee meeting.
Biogen and Elan pulled Tysabri from the market in February 2005 after receiving three reports of PML in patients taking the drug. The FDA advisory panel will discuss whether to allow the drug back on the market.
"Although the three confirmed PML cases occurred in subjects who received a concomitant immune-modulating agent, the data is also insufficient to determine whether natalizumab monotherapy conveys some risk of PML," the FDA review said.
The FDA also is concerned about other opportunistic infections associated with natalizumab administration, according to the agency's background documents.
"If [Tysabri] returns to the marketplace, a risk minimization plan is essential to monitor, and hopefully decrease, the risks associated with natalizumab administration," the FDA said.
In background documents for the meeting, Elan and Biogen said they had "identified PML as a rare, but significant, risk." In addition, serious non-PML opportunistic infections have been observed in natalizumab-treated patients, the firms said.
"In addition, we have identified patient populations in whom the benefit-risk profile is less well-defined who should not receive this treatment," the drugmakers said. "The occurrence of these infections highlights the need for a comprehensive risk management program in the postmarketing setting focused on appropriate use conditions and assessment and minimization of the risk of PML and other serious opportunistic infections."
For more information on the Tysabri meeting, access http://www.fda.gov/oc/advisory/accalendar/2006/cder12543d030706.html (http://www.fda.gov/oc/advisory/accalendar/2006/cder12543d030706.html).