MS Drug Tysabri Approved for Crohn...( But the drug comes with serious risks...),Health

But the drug comes with serious risks, FDA notes

MONDAY, Jan. 14 (HealthDay News) -- Tysabri, a controversial drug used to treat multiple sclerosis, may also be used for patients with a moderate to severe form of another autoimmune illness, Crohn's disease, the U.S. Food and Drug Administration announced Monday.

But the drug also comes with a rare but serious risk of a potentially deadly brain infection, as well as other side effects, so it must be used carefully, the FDA said in a press teleconference.

"With the addition of Tysabri to the treatment options of sufferers of Crohn's disease, we make an important step in the armamentarium for treatment, but one that carries serious risks," said Dr. Joyce Korvick, deputy director of the division of gastroenterology products at the FDA's Office of New Drugs.

Crohn's is a serious, often painful, inflammatory bowel disorder that affects about 600,000 people in the United States. It can involve intestinal bleeding, diarrhea, weight loss, arthritis, skin problems, fever and anemia.

Tysabri (natalizumab), a monoclonal antibody used to treat MS, has been under a cloud of controversy for some time. The drug works by attaching itself to white blood cells called lymphocytes and preventing them from entering the brain, where they do damage that causes the disabling symptoms of MS.

But the drug has a checkered past. It first received U.S. Food and Drug Administration approval in November 2004, only to be pulled from the market three months later after several patients in clinical trials developed a rare but deadly viral infection of the brain called progressive multifocal leukoencephalopathy (PML).

In June 2006, the FDA allowed the drug to return to the market but with strict conditions. According to the new guidelines, Tysabri can only be administered by approved doctors, at infusion sites and pharmacies that register and comply with a patient-safety
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