A new warning letter posted on The Food and Drug Administration Web site that recently included in prescribing information for Tysabri use in patients with Crohn's disease, a chronic, progressive disease marked by inflammation of the bowel. Last month, the FDA approved Tysabri for Crohn's patients who have failed other treatments, including Johnson & Johnson's Remicade and Abbott Laboratories' Humira, although the drug hasn't yet been launched as a treatment for Crohn's.
Tysabri was first approved as an MS treatment in 2004 but was temporarily taken off the market in 2005 over concerns about a serious brain infection. The drug is now sold under a restricted-distribution program, and patients are routinely monitored for signs of the brain infection, known as progressive multifocal leukoencephalopathy, and for other side effects.
The letter to doctors said that the companies has received "clinically significant" reports of liver injury in patients being treated with Tysabri, and that signs of liver injury occurred as early as six days after the first dose of Tysabri. Liver injuries also occurred after multiple doses of the drug.And the letter instructed doctors to tell their patients that Tysabri may cause liver injury and said they should stop drug treatment if patients show signs of liver injury including jaundice.
Shannon Altimari, a Biogen spokeswoman, said the rate of liver injuries is less than one in 1,000 patients. As of the end of December, about 21,000 patients had been treated with Tysabri. None of the injuries required a liver transplant.