Acorda Therapeutics Reports Data from Phase 2 Trial of Delfampridine-ER, Says Data Consistent with Prior Trials
Acorda Therapeutics, Inc. (Nasdaq: ACOR) today announced data from a Phase 2 proof-of-concept study of dalfampridine extended release tablets, 10 mg (dalfampridine-ER) in people with post-stroke deficits. In the study, treatment with dalfampridine-ER was well-tolerated and improved walking, as measured by the Timed 25-Foot Walk test (T25FW). The data were presented at the American Neurological Association 2013 Annual Meeting, being held in New Orleans. Top-line data from this study were disclosed by the Company in April 2013.
Post-stroke deficits refer to chronic neurological deficits, such as impaired walking, motor and/or sensory function that persist in people who have had a stroke. There are currently no pharmacologic therapies indicated to improve function in people with post-stroke deficits.
“In this proof-of-concept clinical trial of dalfampridine-ER in post-stroke deficits, we were encouraged to see a clear signal for improved walking in this population, consistent with the preclinical data. More than half of the seven million stroke survivors in the United States have walking impairment, but there are no approved medications to address this problem,” said Enrique Carrazana, M.D., Acorda's Chief Medical Officer. “Based on the strength of the data, we are planning a larger clinical trial to further assess dalfampridine's safety and tolerability, and potential effect on walking impairment in people with post-stroke deficits.”
The primary goals of the proof-of-concept study were to assess safety and tolerability, as well as to explore various efficacy measures. This study included 83 participants who had experienced an ischemic stroke at least six months prior to treatment and had chronic motor deficits. The average in the study was 10.4 years post-stroke, and the range was up to 35 years. As part of the crossover design, participants received either dalfampridine-ER or placebo twice daily for 14 days (Period 1), followed by a one week wash-out period in which all participants received placebo. This was followed by a second 14-day treatment period (Period 2) during which participants received the alternate treatment.
Key Safety Findings from Post-Stroke Deficits Trial
The safety findings in this study were consistent with previous clinical trials and post-marketing experience of dalfampridine-ER in multiple sclerosis (MS). The overall rate of treatment-emergent adverse events was 54.5% and 37.0% for dalfampridine-ER and placebo, respectively. The most common adverse events reported in the study were dizziness (10.4% dalfampridine-ER, 2.5% placebo), nausea (3.9% dalfampridine-ER, 6.2% placebo), fatigue (5.2% dalfampridine-ER, 3.7% placebo), insomnia (5.2% dalfampridine-ER, 2.5% placebo) and arthralgia (2.6% dalfampridine-ER, 3.7% placebo).
Three participants experienced a seizure during the study. One occurred while the participant was taking placebo (without prior exposure to dalfampridine-ER), one occurred while the participant was taking dalfampridine-ER, and one occurred due to an intentional overdose of dalfampridine-ER. The overdose was judged by the study investigator to be a suicide attempt related to a recent family tragedy. All three participants recovered fully.
Key Efficacy Findings from Post-Stroke Deficits Trial
The primary focus of the exploratory efficacy analyses was walking, as measured by the Timed 25-Foot Walk (T25FW). In the full crossover analysis, which included all T25FW data from both treatment periods, there was a significant increase in walking speed while participants were taking dalfampridine-ER compared to placebo (p = 0.027).
This treatment effect was further supported by separate analyses of the two treatment periods. In both treatment periods there was a greater average improvement in walking speed among participants receiving dalfampridine-ER. These were not statistically significant given the smaller number of measurements in each period compared to the overall analysis.
The walking data were further analyzed using a threshold response analysis, in which the percent of participants achieving sequential levels of improvement over baseline (greater than or equal to 0%, 10%, 20%, 30%, 40%, 50%) was assessed. A higher percentage of patients in both periods improved at all threshold levels while on dalfampridine-ER compared to placebo.
The Company plans to begin a Phase 2b/3 study, pending successful conclusion of a multi-dose, pharmacokinetic study of a once-a-day formulation of dalfampridine-ER, as well as discussions with the U.S. Food and Drug Administration.
The results from other efficacy endpoints in the study will be presented in future scientific communications.
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