An experimental drug called fampridine improves walking ability in some patients with multiple sclerosis (MS), a disease of the nervous system that crimps mobility, a study published on Friday in The Lancet says.
Doctors recruited 301 adults with MS in the United States and Canada, and gave the drug to 229 of the recruits and a dummy lookalike pill, also called a placebo, to 72 others.
Of those who received the drug, just over a third experienced an increase in the speed at which they could walk 25 feet (7.69 metres). The boost in speed was around 25 percent.
Of those who took the placebo, around eight percent had an increase in speed.
The drug was apparently well tolerated. Only 11 people, or less than five percent, of those in fampridine group dropped out of the 14-week trial because of side effects.
"This study indicates that fampridine could represent an important new way to treat multiple sclerosis and perhaps become the first drug to improve certain symptoms of the disease," lead researcher Andrew Goodman, a neurologist at the University of Rochester Medical Center in New York, said in a press release.
"The data suggest that, for a sub-set of MS patients, nervous system function is partially restored while taking the drug."
Around a million people around the world are affected by MS, a degenerative disease in which the immune system attacks myeline, the fatty sheath that protects nerve fibres.
As a result, signals between nerve cells are delayed, disrupted or even blocked, rather like a poor connection in an electrical wire, and this causes worsening problems in coordination and balance, as well as blurred vision and slurred speech.
Current drugs for MS suppress the immune system. They can be useful for slowing progression of the disease, but cannot improve impaired function.
Fampridine does not address the problem of myeline loss. Instead, it is believed to work by blocking channels for potassium ions on the surface of nerve cells.
These channels act rather like gates, and help to regulate electrical impulses.
The study was the final stage in a three-phase process of clinical trials to assess new drugs for safety and effectively.
Fampridine's developer, Acorda Therapeutics, Inc., this month submitted a licence application to the the US watchdog, the Food and Drug Administration (FDA), the press release said.