Jun 03, 2008
Fampridine-SR Improves Walking Speed in All Types of MS in Second Phase 3 Study
Walking speed improved significantly in a clinical trial of 240 people with all types of MS taking Fampridine-SR (MS-F204, Acorda Therapeutics, Inc.) compared with those taking inactive placebo. Fampridine-SR is a sustained-release formula of 4-aminopyridine, which temporarily enhances nerve signaling. These phase 3 study results are reported by Acorda in a press release dated June 2, 2008. The company is planning to file for approval of this drug to treat mobility issues in MS in 2009.
Background: Problems with gait (difficulty in walking) are among the most common mobility limitations in MS. Fampridine-SR is a sustained-release formula of 4-aminopyridine, which blocks tiny pores, or potassium channels, on the surface of nerve fibers. This blocking ability may improve the conduction of nerve signals in nerve fibers whose insulating myelin coating has been damaged by MS. The first studies of this potassium-blocking approach in people with MS were supported by the National MS Society.
In an earlier phase 3 study of 283 people with all types of MS, walking speed increased by 25% compared with placebo. Two serious adverse events led patients to discontinue Fampridine – one case of anxiety and one seizure in a person who developed sepsis from a urinary tract infection. (Abstract #S32.003, AAN 2007)
The Study: Investigators at 39 sites in the United States and Canada recruited 240 people with all types of MS between 18 and 70 years old with some degree of walking disability. Participants were randomly assigned to receive Fampridine-SR (10 mg twice a day) or inactive placebo. The primary endpoint of the study was response on the Timed 25-Foot Walk, in which a patient is directed to one end of a clearly marked 25-foot course and is instructed to walk 25 feet as quickly as possible, but safely.
Results: A significantly greater proportion of people taking Fampridine-SR in the trial had a consistent improvement in walking speed compared to people taking placebo (42.9% vs. 9.3%). Among those taking Fampridine-SR who improved in walking speed, there was a statistically significant improvement in leg strength.
There were three serious adverse events that led to participants leaving the study. In the Fampridine-SR group, one participant had a knee fracture, which was not considered to be related to the treatment. In the placebo group, one individual experienced a partial seizure and another experienced a combination of chest tightness and gastric reflux. Other adverse events reported in the Fampridine-SR treatment group included urinary tract infection, falls, insomnia, and headache.
Further, comprehensive data from this study will be presented at an upcoming medical meeting, according to the press release. “We look forward to hearing more information about this study,” says John Richert, MD, Executive Vice President of Research & Clinical Programs for the National MS Society. “If the FDA agrees that Fampridine is safe and effective, it would bring a welcome symptomatic therapy that has potential utility for a large number of people with different types of MS.”