Late Friday afternoon, January 22, 2010, the Food and Drug Administration (FDA) announced that they approved AMPYRA™ (dalfampridine, formerly known as fampridine-SR) as a treatment to improve walking in multiple sclerosis patients. Developed by Acorda Therapeutics in partnership with Elan Corp, AMPYRA™ is a proprietary slow-release formulation of the compounded drug 4-aminopyridine (4-AP).
Although the name AMPYRA™ only hit the internet on Friday, the drug and its predecessor 4-aminopyridine have a long history. Researchers have been looking into the effects of demyelination on nerve conduction for many decades. The first studies looking into the effect of 4-AP on nerve fibers were published in 1980. See Nature. 1980 Feb 7;283(5747):570-2.
[Agriculturally, 4-aminopyridine chloride, sold under the brand name Avitrol, is used as an extremely effective bird repellant since it works on the central nervous system of baited birds whose behavior then frightens other birds of the flock.]
Please keep in mind that AMPYRA™ (dalfampridine) is an oral symptomatic treatment of multiple sclerosis. It is NOT an immunomodulator which would replace drugs like Avonex, Copaxone, etc. It is a potassium channel blocker which helps electrical impulses travel over demyelinated nerves and should NOT be used by people with a history of seizures or who have moderate to severe kidney disease.
If you’d like to skip the history portion of this article and go straight to the personal stories, continue reading on page 3.
Early research out of London (1969-1983) included published papers related to conduction, demyelination, ion channels, 4-AP and multiple sclerosis. The first clinical study of 4-AP and visual function in MS was published in 1983. See J Neurol Sci. 1983 Aug-Sep;60(3):353-62. Early research from Yale and Brown Universities (1977-1994) include several studies of demyelination and aminopyridine in multiple sclerosis and spinal cord injuries.
Research in Chicago (1974-1991) focused on the use of 4-AP in treatment of MS symptoms. Three small clinical trials performed at Rush Multiple Sclerosis Medical Center in Chicago were published between 1987-1991 in which researchers observed clinical benefits while also comparing oral vs. intravenous delivery of the compound. See Ann Neurol. 1987 Jan;21(1):71-7. See Ann Neurol. 1990 Feb;27(2):186-92. See Neurology. 1991 Sep;41(9):1344-8.
In 1990, Elan Corporation obtained the Know-How related to fampridine (4-aminopyridine) for symptomatic treatment of multiple sclerosis from Rush-Presbyterian Hospital in Chicago. Research continued in Amsterdam (1990-1996) where several clinical studies were conducted including the first large trials of 4-AP in MS looking at its broad effects on disability (EDSS) and long-term safety and efficacy (during one trial two patients had seizures and one developed hepatitis). See Ann Neurol. 1992 Aug;32(2):123-30. See Clin Neuropharmacol. 1993 Jun;16(3):195-204. See Arch Neurol. 1994 Mar;51(3):292-6.