Biogen, Elan Uncover Third Illness in Tysabri Review

The companies pulled the MS drug from the market Feb. 28.
By Robert Steyer ,

Updated from March 30

Biogen Idec

(BIIB) - Get Report

and

Elan

(ELN)

were down sharply in early trading Thursday after their disclosure late Wednesday that they had uncovered a third case of a rare, often fatal central nervous system disease linked to a patient who had used the multiple sclerosis drug Tysabri.

The companies pulled Tysabri from the market Feb. 28 after receiving reports of one death linked to a patient who had taken the drug during clinical trials. A second case of the rare disease was confirmed later.

Both patients took Tysabri for more than 24 months in conjunction with Avonex, an MS drug made by Biogen Idec. However, in the latest case, the patient didn't take Avonex.

The announcement, which came after U.S. markets had closed, hit both stocks in premarket trading Thursday.

Elan, based in Dublin, Ireland, lost $3.88, or 55.6%, to $3.10. Biogen Idec, of Cambridge, Mass. fell $4.10, or 10.7%, to $34.25.

The companies said Wednesday that a patient taking Tysabri during a clinical trial for Crohn's disease, a debilitating gastrointestinal disorder, contracted the rare disease, known as progressive multifocal leukoencphalopathy, or PML.

They said the patient, who died in December 2003, previously had been diagnosed as having malignant astrocytoma, a type of brain cancer, rather than PML. The original diagnosis was made in July 2003.

"As part of this ongoing safety review, the companies, in agreement with the clinical trial investigator, reassessed the case," the companies said. "Following this additional evaluation, the diagnosis is being reassessed as PML."

They said this patient had received eight doses of Tysabri over 18 months. They said the patient also had a history of taking "multiple courses of immunosuppressant agents." They didn't provide details, but such drugs are used to treat people with inflammatory diseases like MS and Crohn's disease as well as people who have received organ transplants.

The companies said they continue to examine clinical trial data, working with investigators to evaluate the approximately 3,000 patients in multiple sclerosis, Crohn's disease and rheumatoid arthritis trials.

"The results of this safety evaluation will be discussed with regulatory agencies to determine possible reinitiation of dosing in clinical trials and future commercial availability," they said.

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