Amgen Inc. said a new study showed its drug Aimovig is an effective preventive treatment for migraine patients who have tried other treatments that either didn’t work or had intolerable side effects, the company announced Tuesday. The Thousand Oaks biotech said 246 patients who had experienced two to four previous preventive treatment failures were randomized to receive monthly injections of either Aimovig or a placebo for 12 weeks. Patients taking Aimovig had nearly three-fold higher odds of having their migraine days cut by at least 50 percent. “These data support the overall efficacy and safety profile we have seen consistently during extensive clinical study of Aimovig, and speak to its potential to help fill treatment gaps in more difficult patient populations whose migraine has not been adequately managed with current therapies,” Dr. Sean Harper, executive vice president of research and development at Amgen, said in a statement. Shares of Amgen (AMGN) closed Tuesday up $3.50, or 2 percent, to $174.88 on the Nasdaq.