FRIDAY, Feb. 17, 2006 (HealthDay News) -- The U.S. Food and Drug Administration announced Thursday that it has approved the clinical trial use of Tysabri (natalizumab), a multiple sclerosis drug voluntarily withdrawn from the market a year ago because of safety concerns.
In a statement released Wednesday, the drug's makers, Biogen IDEC Inc. and Elan Corp., said patients would be invited to re-enroll in the study, which was halted in February 2005.
The two companies also expect a decision from the FDA by late March on an application submitted last September requesting that Tysabri be allowed back onto the market with revised labeling and a strategy to address patient risks.
The FDA said it has scheduled an advisory committee meeting for March 7 and 8 to discuss the use of Tysabri for MS patients with a relapsing form of the disease.
Tysabri was voluntarily withdrawn from the market after two patients with MS and a third with the intestinal disorder Crohn's disease developed a serious condition called progressive multifocal leukoencephalopathy (PML) after taking the drug. The Crohn's patient and one of the MS patients died from the illness.
"The drug is not being placed back on the market at this time," the FDA said. "Although this treatment has been shown to have benefit in patients with relapsing-remitting MS, concern about the risk of PML associated with use of Tysabri remains."
The agency said it has worked with Biogen-IDEC over the past year to make sure that no other clinical trial participants have shown early evidence of PML, and to determine ways of minimizing the risk.
According to officials at Cambridge, Mass.-based Biogen IDEC, any return of Tysabri to the market would involve new labeling warning of potential risks to patients with weakened immune systems, who are most at risk for PML.
More information
To learn more, visit the U.S. Food and Drug Administration.
