Acorda filed a New Drug Application for fampridine on January 30, and FDA approval is expected in about 10 months. If green-lighted, fampridine will be the first drug approved with the indication to improve walking ability in people with MS, and Acordaâ€™s second commercialized product. It currently markets Zanaflex (tizanidine) for the management of spasticity.
This is the second round of late-stage clinical trials for fampridine. In 2004, the drug completed Phase III trials for reducing spasticity in patients with spinal cord injuries, but the studies did not achieve statistical significance in their primary endpoints.
New data from the recent randomized, double-blind, placebo-controlled trial showed an average 25 percent increase in walking speed for MS patients treated with fampridine, compared to a 5 percent increase in the placebo group.
â€œWe focused particularly on walking because walking is by far, along with general energy loss and fatigability, the most pervasive, common, and the most dreaded part of MS,â€ said Acorda CEO Ron Cohen, MD. â€œYou can probably live with one hand being weak if the other handâ€™s OK, but if you canâ€™t walk youâ€™re stuckâ€”youâ€™re utterly dependent.â€
MS is a progressive condition where the immune system attacks the nervous system, destroying myelin and interrupting communication signals between the brain and the spinal cord. Nervous system damage may cause muscle weakness, imbalance, and loss of coordination, which can eventually lead to decreased mobility or paralysis.
According to the National Multiple Sclerosis Society, about 400,000 Americans and 2.5 million people worldwide are diagnosed with MS. Between 64 and 85 percent of those patients have trouble walking.
Used in tandem with first-line medications, fampridine works by blocking the open potassium channels exposed after demyelination, which interrupts message transmission between axons. By sealing the leaks, fampridine allows impulses to flow with reduced interference and restores mobility.
In the early days of MS treatment development (mid-90s) the options were few. As Cohen put it, â€œIt was diagnose and adios.” But with the biotech revolution came giant leaps towards effective MS disease management, and the first line treatmentsâ€”Avonex (interferon beta-1a), Copaxone (glatiramer acetate), Tysabri (natalizumab)â€”were born. Now the next generation of therapy is using the platform built by these veteran drugs as a stage to showcase their new, more targeted approaches. Instead of attempting to slow its progression like older treatments, new drugs take aim at the disease and the debilitating symptoms and side effects that come along with it.
The latest Phase III data translates clinical trial numbers into tangible results for patients. Already, Acorda has solicited the responses of study participants to a 12-Item survey meant to measure fampridineâ€™s perceived impact on mobility improvement.
â€œWe showed that this average 25 percent improvement in walking speed on this test correlates very strongly with improvements in any number of activities in daily life that are related to walking,â€ said Cohen. â€œIt was the first time that anyone had ever shown that a drug could improve neurological function and real functionality in people with MS.â€