['migraine']
['erenumab', 'placebo']

        Inclusion Criteria:

          -  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

        Exclusion Criteria:

          -  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.
      