A second patient taking a recently suspended multiple sclerosis (search)-fighting drug, Tysabri (search), has contracted a rare disease of the central nervous system, the Irish and American companies who developed the highly touted medication confirmed Friday.
Elan Corp. of Ireland and Biogen Idec Inc. of Cambridge, Mass., had announced Monday that they were withdrawing Tysabri because one patient had died of progressive multifocal leukoencephalopathy (search), a usually fatal disease, while a second patient was suspected of developing PML.
The two companies said Friday that a second patient's suspected case of the disease had been confirmed, but he was still alive.
Tysabri had been approved in November by the U.S. Food and Drug Administration following promising clinical trials that demonstrated the drug's ability to prevent relapses in many MS sufferers.
The drug was being used by about 3,000 MS sufferers in the United States and 22 people in Ireland before its withdrawal from the market. Tysabri was also withdrawn from clinical trials on sufferers of Crohn's disease and rheumatoid arthritis.
Both patients were taking Tysabri with Avonex, an older MS-fighting drug developed by Biogen Idec. It has remained on the market.
The companies stressed in a joint statement that, for now, there was no evidence that either drug taken on its own was linked to PML.
"To date, the companies have received no reports of PML in patients receiving Tysabri monotherapy for MS or in patients with Crohn's disease or rheumatoid arthritis," the companies said. "Biogen Idec has not received any reports of PML in patients treated with Avonex alone, a product on the market since 1996."
The companies also confirmed they both were providing unspecified new information to the U.S. Securities and Exchange Commission (news - web sites), which spent two years investigating accounting malpractice at Elan. The Irish company last month paid US$15 million (euro11.4 million) to the SEC to settle the probe.
In the wake of Tysabri's withdrawal, senior figures at Biogen Idec have admitted they sold large volumes of their company's shares in the week before the announcement but have denied any wrongdoing.
Shares in both Elan and Biogen Idec have been hammered this week, losing more than half their value.
By afternoon on the Irish Stock Exchange, Elan's shares had fallen euro0.77 (US$1.01) Friday to euro4.80 (US$6.29). Last Friday, before the Tysabri announcement, its shares closed at euro20.30 ($26.60).
Earlier this week Elan Chief Executive Kelly Martin insisted that the company was hopeful of reintroducing Tysabri — Elan's key drug — to the market later this year.