Health Highlights: August 1, 2008

Aug. 2 -- Here are some of the latest health and medical news developments, compiled by editors of HealthDay:

Reintroduced MS Drug Cited in Two New Deadly Infections

Two new instances of a dangerous brain infection have been reported among users of Tysabri, a multiple sclerosis drug that was reintroduced two years ago after being pulled from the market because of the same adverse effect.

While the two new cases occurred in Europe, they raised international concern about Tysabri and its connection with the viral brain condition called progressive multifocal leukoencephalopathy (PML). The new cases were confirmed this week, according to the Bloomberg news service, which cited a statement from one of the drug's makers, Massachusetts-based Biogen Idec Inc.

Biogen and co-maker Elan Corp, based in Ireland, voluntarily withdrew Tysabri in February 2005 after three users contracted PML and two of them died. The drug was reintroduced in July 2006.

A Biogen spokeswoman told Bloomberg that additional cases had been anticipated and that pulling the drug again was "not under consideration."

Some 31,800 people were taking Tysabri at the end of June, and the companies had hoped to have 100,000 users by 2010, the news service said. The drug also has been approved in the United States to treat an inflammatory bowel disorder called Crohn's disease.

Of the two new cases of PML, one is recovering at home and the other has been hospitalized, Bloomberg said.

"These incidents of PML are unfortunate and disappointing, and we hope for the best possible outcomes for these individuals and their families," the National Multiple Sclerosis Society said in a news release. "However, their occurrence is within range of the predicted frequency of cases, estimated by a published report and by the FDA, of approximately one in 1,000 people taking the drug."

The society said Tysabri users and their doctors should monitor closely for signs of PML, which could include "worsening neurological symptoms such as any changes in thinking, eyesight, balance, strength and other symptoms."