Panel OKs MS drug

Group advising FDA backs Tysabri but proposes restrictions

March 09, 2006|By LOS ANGLES TIMES

WASHINGTON -- An advisory panel unanimously recommended yesterday that the Food and Drug Administration allow back on the market a drug that is effective against multiple sclerosis but also can cause a rare, fatal brain infection.

The committee proposed restrictions on the use of the drug, Tysabri, and the creation of an elaborate system to monitor patients for any sign of the incurable brain ailment, known as PML.

Manufacturers said that in the U.S. alone, 100,000 patients might be interested in taking the medication, which costs an estimated $23,500 a year. There is a substantial additional expense for monthly intravenous infusions.

Tysabri is about twice as effective at treating MS as the drugs currently on the market, but its long-term risks and benefits remain unknown. Scientists at the National Institutes of Health have determined that patients who take the drug have about a 1-in-1,000 chance of developing progressive multifocal leukoencephalopathy, or PML.

"It is likely there will be cases of PML, and likely we are going to see deaths," said the advisory panel's chairman, Dr. Karl Kieburtz, a professor of neurology at the University of Rochester. "The point is, is there a reasonable balance that physicians and patients can reach together? The answer is yes, with some restrictions."

The agency usually follows the recommendations of its advisory committees.

The 12-0 vote came a little more than a year after the medication was pulled from the market by its manufacturers, Biogen Idec Inc. and Elan Corp. That action came after three people taking Tysabri developed PML, an infection sometimes seen in AIDS patients and others with weakened immune systems but very rarely in MS patients. Two of them died.

Multiple sclerosis is a disease in which the immune system turns on the body, attacking the protective coating of nerves in the brain and the spinal cord. Symptoms include blurred vision, numbness, fatigue and paralysis. Although not considered fatal, MS can lead to complete disability.

Tysabri, the first new MS drug in 10 years, is thought to work by preventing certain immune cells from attacking the brain and spinal cord, preventing recurring bouts of debilitating MS symptoms. But FDA staff doctors said it might also block other immune cells from reaching infections in the nervous system, leaving patients vulnerable.

Research has shown that many people carry the virus that causes PML, which is normally kept in check by the immune system.

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