MS drug found effective

NEW YORK — A promising multiple sclerosis drug that was suspended from the market because three people developed a rare brain disease now appears relatively safe and quite effective, three studies found.

The research in today's New England Journal of Medicine comes days before government hearings on whether to allow sales of the drug, Tysabri, to resume.

Tysabri (pronounced ty-SAH-bree) was withdrawn a year ago by Biogen Idec Inc. and Elan Corp. PLC, only months after it had been approved. The Food and Drug Administration last month agreed to allow testing to resume after the company said no more cases of the brain disease had emerged.

The new studies found that Tysabri alone or with standard interferon treatment cut the rate of relapse by as much as two-thirds after two years and reduced the number of people whose MS got worse, compared to those on a dummy treatment or interferon alone.

The studies "confirm that this drug is a significant advance for MS treatment," said Dr. Allan H. Ropper of Boston's Caritas St. Elizabeth's Medical Center, who wrote an editorial in the journal.

Multiple sclerosis, a disease of the central nervous system, afflicts about 350,000 Americans and is more common among women than men. There is no cure and the cause is unknown. Symptoms include trouble seeing and walking. The most common form causes periodic flare-ups of symptoms.

Tysabri was highly anticipated because it works in a different way than existing drugs, which offer only modest help. It blocks destructive immune cells from leaving the bloodstream and entering the brain to inflame and damage nerve tissue.

Patients clamored for the drug when it went on sale, with about 7,000 getting treatment in the first three months.

Then a woman who had gotten Tysabri and interferon for three years died of the brain disease, progressive multifocal leukoencephalopathy, or PML, and a second participant contracted it. Sales of the drug were suspended and tests halted.

A Crohn's disease patient in a Tysabri test for the painful bowel disorder also died of the brain ailment, which is caused by a common virus that is usually dormant. It is most often seen in those with weak immune systems, such as AIDS patients.

An independent committee that included National Institutes of Health scientists reported in the journal that a review found no other cases of the brain infection in other study volunteers. They put the odds of getting PML at 1 in 1,000.