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

- History of migraines (with or without aura) for ≥ 12 months - Migraine frequency: ≥ 4 and < 15 migraine days per month on average acrossthe 3 months prior to screening - Headache (ie, migraine and non-migraine headache) frequency: < 15 headache days per month on average across the 3 months prior to screening - Demonstrated compliance with the eDiary

- Older than 50 years of age at migraine onset. - History of cluster headache or hemiplegic migraine headache. - Unable to differentiate migraine from other headaches - No therapeutic response with > 2 categories for prophylactic treatment of migraine after an adequate therapeutic trial. - Concomitant use of 2 or more medications with possible migraine prophylactic effects within 2 months prior to the start of the baseline phase or during the baseline phase. If only 1 prophylactic medication is used, the dose must be stable within 2 months prior to the start of the baseline phase and throughout the study - Used a prohibited medication, device, or procedure within 2 months prior to the start of the baseline phase or during the baseline phase. - Received botulinum toxin -Anticipated to require any excluded medication, device, or procedure during the study. - Active chronic pain syndromes (such as fibromyalgia and chronic pelvic pain). - History of major psychiatric disorder. - History of seizure disorder or other significant neurological conditions other than migraine. - Human immunodeficiency virus (HIV) infection by history. - Myocardial infarction (MI), stroke, transient ischemic attack (TIA), unstable angina, or coronary artery bypass surgery or other revascularization procedure within 12 months prior to screening. - The subject is at risk of self-harm or harm to others. Previously randomized into an AMG 334 study. - Unlikely to be able to complete all protocol required study visits or procedures, and/or to comply with all required study procedures.