Elan and Biogen Idec have won US approval to market their drug Tysabri for treating the bowel disorder Crohn's disease.
The drug is already sold for the treatment of multiple sclerosis with tight restrictions and a strong warning about a potentially fatal brain infection. The companies must put similar limits on sales for Crohn's disease, the US Food and Drug Administration said.
Crohn's disease is a bowel inflammation that causes sometimes disabling abdominal pain, weight loss, fever and rectal bleeding. Symptoms may be chronic or go into a period of remission. An estimated 500,000 people in the US have Crohn's disease, Elan said.
The FDA approved Tysabri for adults with moderate to severe Crohn's disease who have evidence of inflammation and have a poor response to, or cannot take, other therapies.
In one Elan-sponsored study, 60% of Tysabri patients responded to treatment after 12 weeks of therapy, compared with 44% who got a placebo.
Another study tested patients who initially responded to Tysabri, following them for an additional year. 54% of Tysabri patients had a sustained response through 12 months, compared with 20% of placebo patients, Elan said.
Sales of the drug were suspended in 2005 amid three cases of the brain infection, known as known as progressive multifocal leukoencephalopathy, or PML. The drug returned to the market in 2006 with limits after the FDA decided MS patients were willing to accept the risks in light of possible benefits.
The FDA has ordered similar restrictions for Crohn's sales as it did for MS. Among them, patients must acknowledge risks and agree to be monitored for problems.
The companies expect Tysabri will be available to Crohn's patients by the end of February, Elan said in a statement.
European regulators have recommended against the use of Tysabri for Crohn's disease. Biogen and Elan have said they expect a final decision from the European Commission during the first quarter of 2008.
Elan shares closed down 27 cent at €16.52 in Dublin.
