Study of Sustained Benefit of AMG334 in Adult Episodic Migraine Patients

Inclusion Criteria

• Written informed consent must be obtained before any assessment is performed.
• Adults greater than or equal to 18 years of age upon entry into screening.
• Documented history of migraine (with or without aura) greater than or equal to 12 months prior to screening according to the International Classification of Headache Disorders-3rd Edition (ICHD-3).
• Greater than or equal to 4 and less than 15 days per month of migraine symptoms (based on ICHD-3 criteria) on average across 3 months prior to screening based on retrospective reporting.
• Less than 15 days per month of headache symptoms (i.e., migraine and non-migraine).
• Subjects in need for switching by documented failure of 1 or 2 prophylactic treatments in the last 6 months due to either lack of efficacy or poor tolerability. For subjects with 1 prior treatment failure, the failure should have occurred in the last 6 months. For subjects with 2 prior treatment failures, the second treatment failure should have occurred in the last 6 months.
• During baseline: Confirmed migraine frequency of 4 to 14 migraine days and less than 15 days of headache symptoms.
• During baseline: greater than or equal to 80% compliance with the headache diary.

Exclusion Criteria

• Subjects meeting any of the following criteria are not eligible for inclusion in this study.
• Older than 50 years of age at migraine onset.
• History of cluster headache or hemiplegic migraine headache.
• Unable to differentiate migraine from other headaches.
• Lack of efficacy or poor tolerability with greater than 2 treatments from the 7 medication categories for prophylactic treatment of migraine after an adequate therapeutic trial.
• Efficacy failure is defined as no meaningful reduction in headache frequency, duration, and/or severity after administration of the medication for at least 6 weeks at the generally accepted therapeutic dose(s) based on the investigator's assessment.
• Tolerability failure is defined as documented discontinuation due to adverse events of the respective medication during the last 6 months prior to screening.
• The following scenarios do not constitute lack of therapeutic response:
• Lack of sustained response to a medication.
• Patient decision to halt treatment due to improvement.
• Used a prohibited medication from the 7 categories of prior prophylactic medications within 3 months prior to the start of and during baseline for a non-migraine indication if dose is not stable
• Exposure to botulinum toxin in the head and/or neck region within 4 months.
• Taken the following for any indication in any month during the 2 months prior to the start of the baseline period:
• Ergotamines or triptans on greater than or equal to 10 days per month, or Simple analgesics (non-steroidal anti-inflammatory drugs [NSAIDs], acetaminophen) on greater than or equal to 15 days per month, or
• Opioid- or butalbital-containing analgesics on greater than or equal to 4 days per month.
• Device, or procedure that potentially may interfere with the intensity or number of migraine days within 2 months prior to the start of or during baseline.
• History of major psychiatric disorders (such as schizophrenia or bipolar disorder) or current evidence of depression. Subjects with anxiety disorder and/or major depressive disorders are permitted in the study if they are considered by the investigator to be stable and are taking no more than 1 medication for each disorder. Subjects must have been on a stable dose within the 3 months prior to the start of the baseline period.
• History of seizure disorder or other significant neurological conditions other than migraine. Note: a single childhood febrile seizure is not exclusionary.
• History of malignancy of any organ system (other than localized basal cell carcinoma of the skin or in situ cervical cancer), treated or untreated, within the past 5 years, regardless of whether there is evidence of local recurrence or metastases.
• Human immunodefic