Drug trial shows promise for treating MS symptom

From The New York Times:

A drug developed by Acorda Therapeutics improved the walking ability of some people with multiple sclerosis in a clinical trial, doctors reported Feb. 26. The results could lead to approval of the first drug to treat a specific symptom of the disease.

“This is the first thing that has ever been able to improve the impairment to some degree,” said Dr. Andrew D. Goodman, the lead author of the study, which is being published in The Lancet, a medical journal.

Acorda applied last month for regulatory approval for the drug, called
fampridine, based in part on data from this study. The 14-year-old company, based in Hawthorne, N.Y., already sells one drug, a treatment for spasticity, but it is not yet profitable.

In MS, the immune system attacks the insulation around nerve fibers. That interferes with transmission of signals through the nerves, causing a variety of neurological problems. For many patients difficulty walking is one of the most vexing problems.

The existing drugs for multiple sclerosis are thought to work through the immune system to reduce relapses and slow the development of problems. Acorda’s fampridine, by contrast, improves the ability of the nerve fibers to transmit signals.

It could be used along with other medicines to improve walking in people who already have that disability, said Dr. Goodman, a professor of neurology at the University of Rochester and a consultant to Acorda, which sponsored the trial.

In the trial, which involved 301 patients, 35 percent of those who got the drug walked faster over the 14-week trial period than they had before, compared with 8 percent of those getting a placebo.

Even those who responded to the drug, however, remained disabled. The average speed at which they could walk 25 feet rose from 2 feet a second to 2.5 feet a second. A healthy person can walk about 6 feet a second, Dr. Goodman said.

Still, the patients reported in questionnaires that they could sense the improvement in their ability to do such things as walk outside, climb stairs or stand in one place for a prolonged period. Some other experts were less certain. In a commentary also published in The Lancet, two European experts said that more information was needed to figure out which patients would benefit from the drug.

Nicholas LaRocca, a vice president of the National Multiple Sclerosis Society, said in an interview that he welcomed the drug but added, “It’s a little hard to tell what the overall clinical impact will be.”

There have been signs since the 1980s that fampridine, also known as 4-aminopyridine, could help people with MS. But it also caused dangerous seizures.

Acorda’s formulation, taken as a pill twice a day, releases the drug gradually into the bloodstream, preventing buildup of dangerous concentrations. Acorda licensed worldwide marketing rights for this formulation, which it calls fampridine-SR, for sustained release, from Elan, the Irish drug firm. In the trial, only one person suffered a seizure.

Dr. Ron Cohen, Acorda’s chief executive, said fampridine, if approved, would sell for about $5,000 to $10,000 a year. An estimated 400,000 Americans have MS, and more than half of them have some difficulty walking, according to a poll sponsored by Acorda and the MS society.

Bloomberg News reported this week that Biogen Idec, which sells the MS drugs Avonex and Tysabri, was in talks to buy Acorda or the marketing rights for fampridine. Neither company would comment.

Some of the data in The Lancet paper had been previously announced by the company. Shares of Acorda fell 37 cents, to $23.82 Thursday.