The FDA has expressed doubts about the effectiveness of Acorda Therapeutics' multiple sclerosis drug fampridine-SR, causing the company's shares to drop 13 percent. Fampridine, which is supposed to help MS patients walk faster, can cause seizures. Overall, fampridine met its primary efficacy endpoint, but improvement in walking speed was of questionable clinical significance, noted staffers. Eric Bastings, deputy director of the FDA's Division of Neurology Products, said that while the drug helped patients walk better in trials, the actual number of patients whose walking improved was "numerically quite small, and the average time to complete the 25 foot walk was not different between the treatment groups in either study...[It] appears that the clinical meaning of the differences seen on the primary outcomes is in question." An FDA committee will meet October 14 to determine whether the drug's effectiveness outweighs its side effects.
Biogen Idec forged a $510 million licensing deal with Acorda Therapeutics for the drug, and has already delivered a hefty $110 million up-front fee. Acorda first submitted the drug in March, but the FDA refused to review the drugmaker's application, asking the company to reformat its submission and provide more information. Investors were pleased when the company resubmitted the drug just a month later. The PDUFA action date for the fampridine-SR NDA is October 22, 2009.