WASHINGTON, Mar 28: US regulators yesterday approved a new multiple sclerosis drug made by Biogen Idec Inc that is widely expected to become the No. 1 oral treatment for the disease, with annual sales topping $3 billion. The drug, Tecfidera, activates a chemical pathway in the body known as Nrf2 that helps protect nerve cells from damage and inflammation. Following Wednesday’s approval by the Food and Drug Administration, Biogen said it will launch the drug within the coming days. (agencies)