Company tries new path to treat spinal cord injuries
By Jed Seltzer
NEW YORK, July 24 (Reuters) - In medical school, Dr. Ron Cohen was led to believe there was no way to cure serious spinal cord injuries.
Now, as chief executive of privately held Acorda Therapeutics, Cohen and his research colleagues are trying to debunk conventional wisdom in the medical community: that the nerves in the spinal cord can never function properly again after spinal cord injuries.
"Historically, spinal cord injuries, until about the last 10 years or so, were generally regarded by both physicians and scientists as being impossible to treat," Cohen said.
"You're dealing with thousands of years of established dogma that says no matter what we try, no matter what we do, we cannot figure out the enormous complexity of the central nervous system well enough to intervene therapeutically."
So taking on a tall order, privately held Acorda is starting the last stage of clinical trials of a new drug intended to reduce the uncontrolled muscle spasms and difficulty in arm and leg movement associated with spinal cord injuries.
Acorda hopes to file an application seeking approval to sell the experimental drug, Fampridine SR, with the U.S. Food and Drug Administration before the end of 2003, so patients may be able to take the treatment before the end of 2004. Cohen intends to take Hawthorne, New York-based Acorda public when stock market conditions improve.
Famridine SR may not work for all spinal cord injury patients, but could provide relief for some patients experiencing pain, spasms and stiff limbs from the condition.
More than 250,000 people in the United States live with chronic spinal cord injury, with about 10,000 patients sustaining an injury every year from vehicle accidents, sports injuries or other incidents.
The National Spinal Cord Injury Association, which is based in Bethesda, Md. and serves as a resource center for patients, believes Acorda's experimental treatment is promising.
"Alongside the 250,000 people in the United States and countless others globally who are seeking to maximize function after paralysis from a spinal cord injury, we will be anticipating the news of increased quality of life opportunities for those who will benefit from Fampridine," said Marcie Roth, the association's executive director.
MAXIMIZING SURVIVING NERVES
Most scientists believed that to correct the spinal cord -- the messenger rod between the brain and the rest of the body -- researchers would have to figure out a way to grow new nerves after existing ones were damaged by the injury. But rather than trying to stimulate the growth of new nerves, Acorda's drug maximizes the ability of working nerves to function properly.
In the 1980s, research was published suggesting most spinal cord injuries do not result in a severing of the cord, Cohen said. Instead, most injuries resulting from accidents break the bone that surrounds the cord, crushing the cord but not severing it.
While such incidents destroy a lot of nerve tissues, there are about 2 million axons, or long connectors, that communicate between nerve cells and the brain or nerve cells and the body.
"Many are disrupted or destroyed, but in most cases, some of them are spared," Cohen said.
The nerves that remain intact might not be able to function correctly because such injuries cause damage to the insulation, called myelin, that surrounds many of the nerves.
"The spared nerves are not working not because they're dead but because they've lost their insulation at the site of the injury," Cohen said. "Impulses are being sent from the brain but they're not getting through that naked patch."
Fampridine SR boosts the electrical signal, like an amplifier, so that even though there are patches of lost insulation, the nerve can send its signal through those patches. The drug blocks a process of leaking potassium, which can interrupt nerve signals, that occurs when the myelin insulation is damaged.
In patients with spinal cord injury, interrupted or unsent messages often cause loss of muscle control, bladder control and sexual function, so Fampridine SR may prove effective in halting those symptoms. Acorda is also testing the drug for multiple sclerosis, which often involves myelin damage.
Between 30 percent and 50 percent of patients taking Fampridine SR in earlier clinical trials responded to the therapy, Cohen said, adding that the complex nature of spinal cord injuries may mean that combination therapies prove to be the best way to treat spinal cord injuries rather than a cure-all drug.
"You have to come at it from many different angles to get different benefits for patients along the way," Cohen said.
Most medicines to treat spinal cord injury symptoms are muscle relaxants that don't address the causes of the spasms and have major side effects, such as weakness and lethargy.
Fampridine SR was originally developed by Acorda's partner, Irish drugmaker Elan Corp. (NYSE:ELN - News; Irish:ELN.I - News). |
