More Tysabri Concerns

A possible fifth case of a rare and often fatal brain infection linked to the multiple sclerosis drug Tysabri has been reported to federal regulators, a Food and Drug Administration spokeswoman said Monday.

The case, first reported by the Wall Street Journal, was submitted May 16 through the Food and Drug Administration’s Adverse Event Reporting System, which collects reports of possible drug reactions from physicians and drug makers.

The drug’s makers, Biogen Idec Inc. and Elan Corp., have reported three confirmed cases of progressive multifocal leukoencephalopathy, or PML, in patients taking Tysabri. Two of the patients died, and the third is reported to have shown recent improvement.

A possible fourth case was reported to the FDA this month, but the companies said the diagnosis had not been confirmed.

FDA spokeswoman Lenore Gelb said the fifth report was not confirmed as PML and gave no other details about the case.

Biogen spokeswoman Amy Brockelman said the company, which had planned to produce Tysabri at a plant in Oceanside, Calif., was reviewing the case.

“We hope to have the findings by the end of the summer,” Brockelman said.

PML is a rare disease in which a virus attacks the protective sheath over cells in the central nervous system.

The companies halted sales of Tysabri, formerly known as Antegren, in February.

Although Elan executives have said they are confident they can reintroduce the drug, industry analysts have said that if possible PML cases are confirmed, they could hinder the drug makers’ ability to bring the product back on the market.

Shares of Cambridge, Mass.-based Biogen fell 22 cents to $34.79. Dublin, Ireland-based Elan’s U.S. shares were off 35 cents to $6.78.