FDA GRANTS ACCELERATED APPROVAL OF TYSABRI, FORMERLY ANTEGREN, FOR THE TREATMENT OF MULTIPLE SCLEROSIS
Biogen Idec
Tysabri received a fast-track approval by the FDA for the treatment of relapsing forms of multiple sclerosis.
updated 3/1/2005 10:04:51 AM ET 2005-03-01T15:04:51

When the drug Tysabri was introduced to treat multiple sclerosis just three months ago, there was “a lot of buzz” among people with MS eager to embrace new hope, said Michele Maglione, who was diagnosed with the incurable disease four years ago.

Now, some of that hope has dissolved with news that the drug given fast-track approval by federal regulators has been pulled from the market, said Maglione, a 36-year-old worker at a New York City nonprofit agency, who takes another MS drug, Betasteron.

However, the makers of Tysabri say the medication may eventually return to the market even though it appears the drug — in combination with another medication — triggered a serious disease in two patients, killing one of them.

Massachusetts-based Biogen Idec Inc. and Elan Corp. announced Monday they were voluntarily pulling the drug from the market and advised doctors to suspend prescribing the medication. The companies also have stopped using the drug in clinical trials.

'We're disappointed'
Still, even if the drug is never returned to the marketplace, Tysabri has helped advance research in an area that has seen few successes since the central nervous system disorder was first identified in 1868.

“We’re disappointed,” said Dr. Howard L. Weiner, author of a book on MS and director of the Partners MS Center at Brigham & Women’s Hospital in Boston. “But the results that we saw with this drug moved forward our understanding and treatment of MS, and identified an avenue for treatment that is still very much alive.”

Multiple sclerosis is a brain disease which can lead to muscle weakness, difficulty concentrating, slurred speech and paralysis. About 400,000 Americans and 2.5 million people worldwide are believed to be affected by MS, which is more common in women than men and often strikes between the ages of 20 and 50, according to the MS Society.

While no cure has emerged, Tysabri had been considered a promising therapy because of its unique approach in blocking the movement of inflammatory cells from the bloodstream into the brain, Weiner said.

In patients with multiple sclerosis, their body’s immune system turns rebellious, attacking, inflaming and damaging its own nerve tissue. The most common type of MS involves a worsening, or relapse, of acute symptoms.

The decision to withdraw Tysabri came after recent reports of two cases of serious effects among patients who used it along with an earlier Biogen Idec MS drug, called Avonex, in clinical trials. In one case, the person died; in another, the person developed a suspected case of a rare and frequently fatal disease of the central nervous system.

Both patients had taken Tysabri for more than two years in combination with Avonex, the companies said.

The companies planned to review records from clinical trials, including MRI brain scans, to search for possible further evidence that the drugs — in combination, or Tysabri alone — could put patients at increased risk.

About 5,000 patients have received intravenous infusions of Tysabri since its November approval, Biogen executives said.

Dr. Steven Galson, acting director of FDA’s Center for Drug Evaluation and Research, said that the regulatory agency “continues to believe Tysabri offers great hope to MS patients.”

© 2012 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

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