Biogen Idec and Elan's multiple sclerosis (MS) treatment Tysabri may cause significant liver injury within six days of the first dose, the FDA warned healthcare professionals in a letter posted today on the FDA's website.
Doctors should warn their patients about the drug's liver risk and patients should stop taking Tysabri if they develop jaundice or other symptoms of liver injury, the letter said.
In January the agency approved a supplemental biologics license application for Tysabri to treat Crohn's disease, a chronic and progressive disease marked by inflammation of the bowel. At the time, the companies said they anticipated Tysabri to be available to Crohn's patients by the end of February 2008.
Tysabri was originally approved as a MS treatment in November 2004 but was pulled off the US market in February 2005, after three patients developed a rare and potentially deadly brain infection, progressive multifocal leukoencephalopathy (PML).
That FDA allowed Tysabri back on the market in June 2006 under a restricted distribution program dubbed the “Tysabri Outreach: Unified Commitment to Health” (TOUCH) prescribing program.
Before Tysabri treatment for MS can start, patients must undergo a magnetic resonance imaging scan. Then, patients on Tysabri are to be evaluated at three and six months after the first infusion, and every six months after that, with their status being reported directly to Biogen Idec.
Biogen Idec said more than 21,000 patients are using Tysabri and so far there haven't been any additional reports of PML.
Tysabri for Crohn's is expected to compete with Remicade, the leading treatment in the category, made by Johnson & Johnson.
Tysabri, generated $129 million in worldwide sales in the fourth quarter of 2007 and was being taken by 21,000 patients at year-end, according to Biogen.