Weapon against MS: transplant drug limits nerve damage.

A drug originally devised to prevent immune rejection of organ transplants can lessen relapses in patients with multiple sclerosis, a new study finds.

The drug, called fingolimod, inhibits immune cells from destroying the fatty coatings of nerve fibers in the brain and spinal cord. Damage of such myelin sheaths leads to multiple sclerosis (MS) symptoms, which include fatigue, balance problems, and loss of muscle control.

Although preliminary, the study is the second piece of welcome news this year for MS patients. Citing new findings (SN: 3/4/06, p. 131) of the effectiveness and safety of the drug natalizumab (Tysabri), the Food and Drug Administration in June reinstated it for some MS patients. The agency had approved the drug in 2004, but sales were halted for safety reasons.

In the latest study, researchers in Europe and Canada gave a daily fingolimod pill to 160 MS patients. Half the recipients got a dose four times as high as the dose that the others received. Another group of 81 patients received inert pills.

All the patients saw a doctor regularly and underwent monthly magnetic resonance imaging (MRI) to detect myelin-sheath damage in the brain or spinal cord. The doctors didn't know which patients were receiving doses of the drug or the placebo.

Over 6 months, patients getting either drug dose were less than half as likely as the placebo patients to relapse, either developing new or stronger MS symptoms, says study coauthor Ludwig Kappos, a neurologist at the University Hospital Basel in Switzerland. MRI scans during that time revealed that patients getting the drug had fewer new sites of myelin damage than the participants receiving the placebo had.

After 6 months, the patients getting the placebo were switched to one of the fingolimod doses. Over 6 more months, most of those people had fewer relapses and fewer sites of new myelin damage than they had while receiving the placebo, the scientists report in the Sept. 14 New England Journal of Medicine (NEJM).

Fingolimod suppresses immunity. People taking the higher dose were more likely than those in the other groups to get upper respiratory infections, the researchers say.

Fingolimod appears to work by snagging newly minted immune cells that target myelin in the central nervous system and sequestering them in lymph nodes, pathologists Steffen Massberg and Ulrich von Andrian of Harvard Medical School in Boston say in the NEJM carrying the new study.

"These data are impressive," says Peter A. Calabresi, a neurologist at Johns Hopkins Medical Institutions in Baltimore. Judging from this study, fingolimod may hold off relapses better than do common MS drugs such as interferon. Only natalizumab, which is injected monthly, has performed better in tests, says Calabresi, who acknowledges that he has consulted for Novartis, the Switzerland-based manufacturer that makes fingolimod and funded the new study.

Effectiveness aside, fingolimod's real advantage might be that it's a pill, Calabresi says. "All the other drugs we have on the market are injectable therapies," he notes.

Two longer-term studies with more participants are under way, Kappos says. One is testing fingolimod against interferon beta-la injections, and the other is another comparison with a placebo.