Comeback Begins for Tysabri

Updated from June 5

The official word has come down, and Tysabri is going back on the market, but U.S. regulators determined that the label for the multiple sclerosis drug will have to carry their strongest type of cautionary statement.

Biogen Idec and Elan (ELN Quote), the marketers of Tysabri, said Monday that the Food and Drug Administration has approved the product's return after a 16-month absence.

However, the drug's label will also contain what's called a black box warning because Tysabri was linked to a potentially fatal brain disease last year. The agency also recommended the drug be prescribed for patients who haven't responded well to other MS therapies or who can't tolerate other options.

Next up is Europe. Biogen CEO James Mullen said on a conference call Tuesday that his company and Elan expect to receive approval for Tysabri from European regulators in July. The drug would probably be available by the first half of 2007 in most major European markets, he added.

Tysabri can be used as a stand-alone treatment for relapsing forms of MS, to slow the progression of the disease and to reduce the recurrence of symptoms of the neuromuscular disease. Tysabri will probably be available next month, the companies said.

"We are pleased with the FDA's decision to once again make Tysabri available to patients and their families suffering from this chronic, debilitating disease," Kelly Martin, Elan's chief executive, said in a statement. "There continues to be a significant unmet medical need where Tysabri will be an important treatment option."

Following word of the decision, Biogen's shares fell about 5%, and Elan dropped nearly 12%. On Tuesday, Biogen recovered a bit, gaining 33 cents, or 0.7%, to $45.72. Elan though, was down another 65 cents, or 3.9%, to $15.87.

An outside panel of experts earlier this year had urged the FDA to reapprove the drug following emotional pleas from a number of patients who wanted access to Tysabri.

Biogen and Elan pulled Tysabri off the market early last year after the drug, when combined with another immune-system suppressant, was connected to a serious brain disease called progressive multifocal leukoencephalopathy. Three cases of the illness were ultimately found. In two cases, the patients died.