By Luke Timmerman and Catherine Larkin
Feb. 27 (Bloomberg) -- Biogen Idec Inc. and Elan Corp.'s multiple sclerosis medicine Tysabri may cause significant liver injury within six days of the first dose, U.S. regulators said.
Patients should stop taking Tysabri if they develop jaundice or other symptoms of liver injury, according to a letter to doctors from the drugmakers that was posted today on the Food and Drug Administration's Web site. Doctors should warn patients about the drug's liver risk, the FDA said.
Tysabri, Biogen's fastest-growing product, generated $129 million in worldwide sales in the fourth quarter and was being taken by 21,000 patients at year-end, according to Biogen. The companies pulled the drug from the market in February 2005 because two patients developed fatal brain infections. The drug was reintroduced in July 2006 after the FDA decided the benefits in slowing multiple sclerosis relapses outweighed the risks.
``At Biogen and Elan, patient safety is our highest priority,'' the companies said in the letter to physicians that is dated this month. ``We are committed to ensuring that health- care professionals continue to receive the necessary information to prescribe Tysabri appropriately.''
Biogen fell 76 cents, or 1.2 percent, to $60.77 at 12:59 p.m. New York time in Nasdaq Stock Market composite trading, after touching $57.95. That 5.8 percent decrease would be the biggest drop in more than two months. The stock has gained 30 percent in the 12 months before today. Elan climbed 11 cents, to 16.59 euros in Dublin trading.
The companies, which market the product together, issued the warning letter after patients developed unusually high levels of liver enzymes in the blood, a sign of liver injury, according to the letter. The injury recurred in some patients after they were given another dose of the drug, ``providing evidence that Tysabri caused the injury,'' according to the letter.
Previous Reports
In July, the FDA cited 28 cases of liver injury associated with Tysabri since November 2004, four of them potentially serious. Elan spokesman Andrew Lewis said at the time the cases were from ``post-marketing experience.'' Tysabri won an additional approval for Crohn's disease in January, after the FDA considered the liver injuries.
Revised prescribing information approved in January includes the liver risks.
Biogen is counting on sales of Tysabri to fuel its growth. The company said this month that it expects 100,000 patients to be taking Tysabri by the end of 2010, which translates to about $2.8 billion in annual sales at current prices.
Biogen is based in Cambridge, Massachusetts. Elan is based in Dublin, Ireland.
To contact the reporters on this story: Luke Timmerman in San Francisco at +1- ltimmerman@bloomberg.net ; Catherine Larkin in Washington at clarkin4@bloomberg.net .
