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
"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.
November 2004: The FDA first approves Tysabri for the treatment of
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
March 2006: Researchers report
no new cases of PML in patients who took Tysabri before the drug's
FDA panel unanimously recommends returning Tysabri to the market.
June 2006: The FDA allowed Tysabri back on the market under a restricted
distribution program to treat relapsing forms of multiple sclerosis.
SOURCES: Joyce Korvick, MD, Deputy Director, Division of Gastroenterology
Products, Office of New Drugs, Center for Drug Evaluation and Research, FDA.
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