By Jennifer Corbett Dooren
Of DOW JONES NEWSWIRES
WASHINGTON -(Dow Jones)- A Food and Drug Administration panel said a proposed Acorda Therapeutics (ACOR) drug to treat multiple-sclerosis appeared to be effective at increasing walking speed.
The drug, fampridine-SR, is being reviewed Wednesday by an outside panel of medical experts. The panel voted 12 to 1 in favor of a question that asked if the company "demonstrated substantial evidence of effectiveness of fampridine as a treatment to improve walking in patients with multiple sclerosis." The panel is currently discussing whether the improvement is clinically meaningful and whether the product is safe. Fampridine has been associated with a seizure risk at higher doses than the 10-milligram dose for which Acorda is seeking FDA approval.
The FDA said one study of about 300 patients showed that 34.8% of patients receiving fampridine-SR had an improvement in walking speed compared to 8.3% in the placebo group. Patients were timed as part of a 25-foot walking test at different time points during treatment. Another study involving 237 patients showed 42.9% of patients in the fampridine group had an improvement in walking speed compared to 9.3% of patients in the placebo group.
But an agency reviewer said the "improvement in walking speed is of small magnitude and of uncertain clinical significance."
The active ingredient in the drug - fampridine - has been compounded in pharmacies for more than 20 years and used to improve walking in a number of neurological conditions. The drug is currently not approved by the FDA for any use.
The FDA said data from the clinical trial of fampridine-SR at 10-milligrams given twice a day didn't show a difference in the seizure risk compared to patients treated with a placebo, or fake drug. However, the agency said in briefing documents prepared for the meeting that there was a 10-fold increase in the risk of a seizure when the drug was dosed at 20-milligrams twice daily, "a concerning finding suggesting a narrow therapeutic index."
Multiple-sclerosis is a progressive disease that involves damage to nerves controlling muscles and vision, and affects about 400,000 Americans. The condition causes the body's immune system to eat away at the protective covering of the nerves, or myelin, which disrupts the electrical signals between the brain and the rest of the body. Fampridine-SR is designed to help the body's electric signals to pass through by blocking potassium ions that leak from the damaged nerves.
-By Jennifer Corbett Dooren, Dow Jones Newswires; 202-862-9294; jennifer.corbett@dowjones.com