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 earlier Monday, 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. Plc , 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 earlier this month, but the companies said the PML diagnosis has 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 spokeswomen Amy Brockelman said the company was reviewing the case.
“We hope to have the findings by the end of the summer,” Brockelman said. The company would then share its safety reports with the FDA and decide its next step for the drug.
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.
While Elan officials have said they are confident they can reintroduce the drug, industry analysts have said if possible PML cases are confirmed they could hinder the drugmakers’ ability to bring the product back on the market.
According to the newspaper report, the fifth possible case concerns a female patient, of an undisclosed age, who has been hospitalized. The FDA’s Gelb said she could not comment on the patient’s condition.
Elan spokesman Brian McGlynn said the company had no comment.
