The objective of the analysis was to validate a consistent response criterion as a measure of clinically meaningful change. A consistent timed walk responder was defined as a subject whose walking speeds for at least three of the four on-treatment visits were faster than the fastest speed across any of their five non-treatment visits. In both studies, Fampridine-SR treatment was associated with significantly increased probability of this response compared to placebo (p less than 0.001). Both clinical trials were double-blind, placebo-controlled, parallel group, multi-center studies. The analysis was designed after the data from the first study were available. A total of 501 patients were included in the analysis.
The clinical meaningfulness of this response criterion was assessed primarily by use of the 12-Item MS Walking Scale (MSWS-12), a questionnaire in which the patient rates the clinical impact of his or her walking disability on activities of daily life. Additional criteria for clinical meaningfulness included a seven-point Subject Global Impression (SGI) and a seven-point Clinician Global Impression (CGI). In the meta-analysis, timed-walk responders had significantly greater average improvements from baseline in the MSWS-12 score than the non-responders in both studies in dividually (p=0.02 and p less than 0.001, respectively) and in the meta-analysis (p less than 0.001). In addition, average scores for all 12 individual questions in the MSWS-12 were better for timed walk responders in both studies.
Timed walk responders also showed significantly better SGI scores than non-responders in the meta-analysis (p less than 0.001) and in both studies individually (p=0.004 and p less than 0.001, respectively). The CGI was applied differently in the two studies, so the meta-analysis was not performed. It showed a strong trend in the retrospective analysis of the first trial (p=0.056) and significant improvement for responders versus non-responders in the second trial (p less than 0.001).
The validation of the consistent timed walk response criterion was consistent across the studies as well as in the patient subgroups examined. The subgroups included patients with all of the four major types of MS course as well as patients with a wide range of disability at baseline.
Andrew Goodman, M.D., Professor of Neurology, Chief, Neuroimmunology Unit, Director, Multiple Sclerosis Clinic at the University of Rochester Medical School said, "Walking impairment is one of the most common and critical problems for patients with MS, impacting a wide range of their activities. There are no therapies available today that are indicated for improving mobility in patients with MS. This meta-analysis found that the consistent improvement in walking speed on the Timed 25-Foot Walk represented clinically meaningful improvements for patients, as measured by three independent scales."
Fampridine-SR is a sustained-release tablet formulation of the investigational drug fampridine (4-aminopyridine, or 4-AP). Data collected in laboratory studies found that fampridine can improve the communication between damaged nerves, which may result in increased neurological function.
Fampridine-SR Mechanism of Action
A nerve cell has one extension, called an axon, which it uses to communicate via electrical signals to other nerve cells. All but the smallest axons have a special covering of a fatty substance called myelin that acts as insulation to preserve and speed these nerve signals, much like the insulating cover of an electrical cord helps preserve the transmission of electricity.
In MS, the myelin becomes damaged and the axon cannot effectively transmit electrical impulses. Specifically, the damaged myelin exposes channels in the membrane of the axon, which allow potassium ions to leak from the axon, dissipating the electrical current. Fampridine-SR blocks these exposed channels, and helps the electrical signals to pass through areas of damage.
Forward Looking Statements
This press release includes forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. All statements, other than statements of historical facts, regarding management's expectations, beliefs, goals, plans or prospects should be considered forward-looking. These statements are subject to risks and uncertainties that could cause actual results to differ materially, including Acorda Therapeutics' ability to successfully market and sell Zanaflex Capsules, the risk of unfavorable results from future studies of Fampridine-SR, delays in obtaining or failure to obtain FDA approval of Fampridine-SR, competition, the ability to obtain additional financing to support Acorda Therapeutics' operations, unfavorable results from its preclinical programs, and failure to protect its intellectual property or to defend against the intellectual property claims of others. These and other risks are described in greater detail in Acorda Therapeutics' filings with the Securities and Exchange Commission. Acorda Therapeutics may not actually achieve the goals or plans described in its forward-looking statements, and investors should not place undue reliance on these s tatements. Acorda Therapeutics disclaims any intent or obligation to update any forward-looking statements as a result of developments occurring after the date of this press release.
About Acorda Therapeutics
Acorda Therapeutics is a biotechnology company developing therapies for SCI, MS and related nervous system disorders. The Company's marketed products include Zanaflex Capsules(TM) (tizanidine hydrochloride), a short-acting drug for the management of spasticity. For full prescribing information, please go to www.zanaflexcapsules.com. Acorda's lead clinical stage product, Fampridine-SR, recently completed a Phase 3 study in people with MS. The Company's pipeline includes a number of products in development for the treatment, regeneration and repair of the spinal cord and brain.
Erica Wishner, 914-347-4300 ext. 162