A multi-center clinical trial is about to be launched in the United States and Canada to test an oral medication for multiple sclerosis (MS) designed to improve walking ability in people with the disease.
This will be a pivotal Phase 3 clinical trial, meaning if the results turn out to be positive, an application for approval of the drug to treat MS will likely be submitted to the Food and Drug Administration. The trial's findings will serve as a basis for the application.
Helping Nerve Fibers Communicate
The medication, labeled Fampridine-SR, is the sustained-release, oral form of the investigational drug, Fampridine. According to its manufacturer, Acorda Therapeutics, the drug is currently being tested in several clinical trials as a therapy for both MS and spinal cord injury. In preclinical trials, the drug has been shown to improve impulse conduction in nerve fibers after myelin has been damaged.
Myelin is a fatty substance that covers and protects nerve fibers in the central nervous system, allowing them to conduct impulses between each other. When MS occurs, it's believed the immune system goes haywire, attacking and destroying myelin erroneously. This leaves scar tissue in the brain and spinal cord. It also leaves nerve endings unprotected and vulnerable, meaning they can no longer conduct impulses properly. The result is the various symptoms manifested in MS.1
Can Fampridine Help Your Mobility?
In the most recent trial of Fampridine, a Phase 2 study, there was a positive trend toward improvement in average walking speed among 211 patients who had taken the drug, the study investigators reported.2 That means that while the walking improvements may have occurred by chance, it was more likely that the medication was actually responsible. More than 200 people with the disease were randomly assigned in the study to a group taking twice-daily doses of the drug or a group taking an inactive placebo. The trial lasted for 12 weeks.
Side effects reported in the trial included dizziness, insomnia, and nausea. Two people in the study experienced seizures, but in one case, they were caused by an accidental overdose, the researchers reported.
An 'Unmet Medical Need'
"Walking disability is one of the most important areas of unmet medical need in this population," said Andrew Goodman, MD, director of the MS Center at the University of Rochester, and chairman of Acorda's MS advisory group. "Today's MS therapies act to prevent relapses and slow the progression of the disease, but do not address the considerable loss of function experienced by these patients."
Goodman headed the Phase 2 trial of Fampridine-SR.
The drug works by blocking tiny pores known as potassium channels on the surfaces of nerve fibers after myelin has been damaged. By blocking the pores, impulse conduction may be improved between the fibers, helping lessen the symptoms of multiple sclerosis, and in this case, possibly improve mobility.
"A drug that could improve walking ability would be a significant and complementary addition to the current array of available therapies," Goodman stated.
Immobility is a Common Symptom
According to the National MS Society,3 half of those with relapsing MS will need some assistance walking within 15 years of diagnosis. This occurs because the damage the disease inflicts on nerve fibers negatively affects coordination, and causes weakness, poor balance, numbness, or spasticity.
Many patients with walking difficulties are referred to a physical therapist, who, along with your physician, will come up with a plan of action for you.3
Enrollment Prerequisites
Meanwhile, people eligible to take part in the upcoming Phase 3 trial of Fampridine-SR should be between ages 18 and 70 with clinically definite MS of any form. Study participants must have adequate cognitive function, and must be able to perform the study procedures, which will include tests of walking speed. The participants must be able to walk, although with some difficulty.
If you are on disease-modifying therapy, participation will likely be acceptable, but participants must discuss details of the therapy with the trial's coordinator.
"Accorda's mission is to develop therapies that improve neurological function in people with MS, spinal cord injury, and related neurological disorders," said Ron Cohen, MD, president and CEO of the pharmaceutical company, in a statement. "We are delighted to have launched this pivotal trial, which is a key milestone in the fulfillment of that mission."
1. National Multiple Sclerosis Society. What is Multiple Sclerosis? Available at: http://www.nationalmssociety.org/What%20is%20MS.asp. Accessed July 29, 2005.
2. American Committee for Treatment and Research in MS, 2004.
3. National Multiple Sclerosis Society. Gait or Walking Problems: The Basic Facts. Available at: http://www.nationalmssociety.org/Brochures-On%20Gait.asp. Accessed July 29, 2005.
John Martin is a long-time health journalist and an editor for Priority Healthcare. His credits include overseeing health news coverage for the website of Fox Television's The Health Network, and articles for the New York Post and other consumer and trade publications.
