03.08.06, 12:00 AM ET
WEDNESDAY, March 8 (HealthDay News) — A U.S. Food and Drug Administration advisory panel voted unanimously Wednesday to allow the promising but controversial multiple sclerosis drug Tysabri back on the market.
The advisers continued to discuss certain controls on who could use the drug, which has been linked to a rare but potentially fatal brain infection. The panel members agreed to a manufacturer plan for a mandatory patient registry; they were scheduled to decide later in the day who would be allowed to enroll in the registry, and how tightly drug use would be limited, the Associated Press reported.
While the full FDA generally follows the recommendations of its advisory panels, it is not required to do so. The agency is expected to render its final decision on the drug by the end of the month.
Physicians and MS patients alike were heartened by the decision, which came during the second day of two days of deliberations.
“Tysabri is a very important step forward despite the fact that there are some concerns and limitations concerning its safety, but the safety risk at the moment, in the range of about one in 1,000, is probably well worth taking for patients with more severe or unstable disease,” said Dr. Joseph Herbert, director of the Multiple Sclerosis Care Center and chief of neurology at New York University/Hospital for Joint Diseases in New York City.
“Patients with rapidly progressive or aggressive MS are probably at far greater risk because of the disease than they are from a potential rare side effect of the drug,” Herbert said.
MS patient and attorney Karen Miller, 49, told the committee that Tysabri “is as close as it comes” to a miracle drug. Miller credited the drug with a renewed ability to ride her bike, wash her windows and run daily errands, the AP said.
“I am at the end of my road, in terms of what I can take. I want it to be my choice,” another MS patient, Barbara Crooks, 48, told the news service.
Tysabri’s manufacturers, Biogen Idec Inc. and Elan Corp, pulled the drug off the market in February 2005 after three patients taking it developed progressive multifocal leucoencephalopathy (PML), a progressive, neurodegenerative disease. Two of those patients died.
The removal took place just three months after the FDA had granted accelerated approval of the drug for the treatment of relapsing forms of MS.
In February, the FDA announced that Biogen and Elan could resume clinical trials for MS patients who were previously treated with the drug under an investigational study.
According to the National Institute of Neurological Disorders and Stroke, multiple sclerosis is an unpredictable disease of the central nervous system that can range from relatively benign to somewhat disabling to devastating. Most MS patients experience their first symptoms between the ages of 20 and 40, and most suffer muscle weakness in their extremities and difficulty with coordination and balance. These symptoms may be bad enough to hamper walking or even standing; in worst cases, MS can produce partial or complete paralysis.
Tysabri is a monoclonal antibody, engineered to attach itself to white blood cells called lymphocytes and prevent them from entering the brain, where they do damage that causes the disabling symptoms of MS. Tysabri had also been used to treat Crohn’s disease.
One of the biggest issues in bringing the drug back to market is what kind of risk-management plan should be implemented. An initial plan submitted to the FDA by the manufacturers was considered insufficient.
“There’s no question with this kind of essentially lethal risk that there is going to have to be some kind of risk-management program,” Dr. Robert Temple, director of the FDA’s Center for Drug Evaluation and Research, said at a Tuesday news conference.
Other features of a risk-management plan could include restrictions on who gets the drug, administering the drug at a registered infusion center, and monitoring all patients on the drug for at least five years. The drug may be restricted only to individuals with more severe forms of the disease, patients who have failed other therapies, and patients who are not taking other immunosuppressants.
“The three cases that did develop PML were all patients who were on other immune modulator drugs,” Herbert noted. “If we use Tysabri judiciously and as a monotherapy, it is possible that the risk will turn out to be lower than we imagine.”
Tysabri is only the second prescription drug to be returned to the market after being taken off. The other was Lotronex, used for irritable bowel syndrome, which was withdrawn in 2000 but allowed back on the market two years later.
“Lotronex was a unique drug with value for some people,” Temple said. “The drugs that disappear permanently tend to be drugs that tend to have substitutes.”
Find out more about Tysabri at the U.S. Food and Drug Administration.
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