Biogen Idec Inc. (BIIB) and Bayer AG (BAYN) would have to cut the price of their multiple sclerosis drugs by at least two-thirds in the U.S. to make them cost effective at boosting quality of life, a study found. Disease-modifying drugs for MS like Avonex from Weston, Massachusetts-based Biogen, and Betaseron, sold by Leverkusen, Germany-based Bayer, are at least eight times costlier than what researchers consider reasonable when putting a price on quality- of-life improvement, according to the study published today in the journal Neurology. The study also found that prescribing the drugs in earlier stages of MS improved cost effectiveness.