Biogen Idec (NASDAQ: BIIB) today issued the following statement regarding the United States (U.S.) Food and Drug Administration (FDA) approval of AMPYRA™ (dalfampridine) to improve walking in patients with multiple sclerosis (MS). This was demonstrated by an increase in walking speed. The U.S. FDA approval was granted on January 22, 2010. AMPYRA will be marketed in the U…