"The chemical was commonly used in physiology laboratories where scientists were studying normal nerve conduction, but at the time it was used clinically only by physicians in Bulgaria, then a Communist-block country," Davis said. "They didn't know how it worked, but they used it to help patients recover from anesthesia-induced paralysis more quickly."
In 1983, in a small proof-of-concept study, Davis and Stefoski injected the drug in 11 patients whose motor function and eyesight were impaired because of multiple sclerosis.
"It was stunning," Stefoski said. "After a single intravenous dose, the patients could walk better and see better."
Rush was granted market exclusivity by the FDA under the Orphan Drug Act of 1983 and licensed worldwide rights for dalfampridine first to Ireland-based Elan Corporation and subsequently to Acorda Therapeutics, Inc., located in Hawthorne, New York. This month, Acorda began marketing dalfampridine in the U.S. under the brand name Ampyra.
In two Phase III clinical trials conducted by Acorda, the drug yielded a consistent improvement in walking speed. Walking speed increased by about 25 percent in 35 percent of patients in one trial and in 43 percent of patients in the other, as measured by a standard test called the Timed 25-Foot Walk. Study participants who took the drug also experienced greater leg strength than those who took a placebo.
Stefoski said that although the drug has been approved specifically for the treatment of impaired walking, it also relieves other symptoms of multiple sclerosis, since it restores signal conduction in all the affected nerve fibers.
Multiple sclerosis is a chronic, often disabling autoimmune disease. According to the National Multiple Sclerosis Society, more than 2.5 million people worldwide and 400,00
|Contact: Sharon Butler|
Rush University Medical Center