Study to Evaluate the Efficacy and Safety of Erenumab (AMG 334) Compared to Placebo in Migraine Prevention

Adults with a history of migraine with or without aura for ≥ 12 months and who experience ≥ 4 to \< 15 migraine days per month with \< 15 headache days per month will be randomized 1:1 to placebo or erenumab. Double-blind erenumab or placebo will be administered during the 12-week double-blind treatment phase and open-label erenumab will be administered during the 28-week open-label treatment phase.