US FDA points to seizure risk with Acorda's MS drug Ampyra

The US Food and Drug Administration has issued a warning about the risk of seizures in patients with multiple sclerosis (MS) who are starting therapy with Ampyra (dalfampridine), marketed by Acorda Therapeutics (Nasdaq: ACOR).

Using information received from post-market adverse event reports, the FDA recently evaluated seizure risk in MS patients taking Ampyra. The majority of seizures happened within days to weeks after starting the recommended dose and occurred in patients having no history of seizures, the agency said.

Ampyra was approved January 22, 2010, to improve walking in patients with MS; approval was based on increased walking speed. Although the mechanism of action in MS patients is not fully understood, studies in animals show increased neuronal activity in response to the drug. According to Acorda, around 46,000 patients received prescriptions for Ampyra between March 2010 and March 2011.