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 Thursday’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Tysabri (pronounced ty-SAH-bree) was withdrawn a year ago by Biogen Idec Inc. and Elan Corp.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 with 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.