Tysabri may be used to treat patients who have moderate to severe Crohn's disease with evidence of inflammation who don't adequately respond to or can't tolerate other Crohn's disease therapies.
Tysabri, a biologic drug given by health care professionals at infusion centers, carries a "black box" warning (the FDA's sternest warning) about the risk of a rare, serious brain disease called progressive multifocal leukoencephalopathy (PML).
Tysabri was taken off the market in February 2005 because of that risk. The drug returned to the market in June 2006 under a restricted distribution program after no new cases of PML were seen in patients who had taken Tysabri prior to the drug's suspension.
Crohn's patients who take Tysabri -- and doctors, infusion centers, and pharmacies that provide Tysabri -- must enroll in the restricted Crohn's Disease Tysabri Outreach Unified Commitment to Health, or CD TOUCH, prescribing program.
"With the addition of Tysabri to the treatment options for sufferers of Crohn's disease, we make an important step in the armamentarium for treatment, but one that carries serious risks," Joyce Korvick, MD, deputy director of the FDA's division of gastroenterology products, told reporters. "Health care providers must carefully monitor patients for these risks."
Korvick also confirmed that no new cases of PML have been reported in Tysabri users since the drug returned to market. Tysabri's makers, Biogen Idec and Elan, will conduct long-term surveillance studies of Tysabri, including monitoring PML cases, says Korvick.
Tysabri Time Line
Here's a quick recap of Tysabri's history:
February 2005: Tysabri's makers, the drug companies Biogen-Idec and Elan, take Tysabri off the market after three people out of about 3,000 patients taking Tysabri in clinical trials developed a rare, serious brain infection called progressive multifocal leukoencephalopathy (PML). Two of those patients died.