Study of Efficacy and Safety of AMG 334 in Adult Episodic Migraine Patients

Percentage of Participants With at Least a 50% Reduction From Baseline in Monthly Migraine Days at Month 3

Achievement of at least a 50% reduction from baseline in monthly migraine days at Month 3. A migraine day was defined as any calendar day in which the subject experienced a qualified migraine headache defined as a migraine with or without aura, lasting for ≥ 30 minutes, and meeting at least one of the following criteria: 1. ≥ 2 of the following pain features: unilateral, throbbing, moderate to severe or exacerbated with exercise/physical activity 2. ≥ 1 of the following associated symptoms: nausea and/or vomiting, photophobia and phonophobia

Time frame: Baseline and at Month 3

Change From Baseline in Acute Migraine-specific Medication Treatment Days at Month 3

Number of days on which acute migraine-specific medications were used were recorded in eDiary between each monthly IP dose. Migraine-Specific medications include two categories of medications: triptan-based migraine medications and ergotamine-based migraine medications. Monthly migraine-specific medication use at baseline is the number of migraine-specific medication treatment days in the baseline period.

Time frame: Baseline up to Month 3

Change From Baseline in Headache Impact Scores as Measured by the Headache Impact Test (HIT-6) at Month 3

The HIT-6 is a short-form self-administered questionnaire based on the internet-HIT question pool. The HIT-6 was developed as a global measure of adverse headache impact to assess headache severity in the previous month and change in a patient's clinical status over a short period of time. Six items assess the frequency of pain severity, headaches limiting daily activity (household, work, school, and social). Each of the 6 questions is responded to using 1 of 5 response categories: "never," "rarely," "sometimes," "very often," or "always." For each HIT-6 item, 6, 8, 10, 11, or 13 points, respectively, are assigned to the response provided. These points were summed to produce a total HIT-6 score that ranges from 36 to 78. Scores were categorized into 4 grades, representing little or no impact (49 or less), some impact (50-55), substantial impact (56-59), and severe impact (60-78) due to headache. Lower values represent better outcomes, therefore negative change denotes improveme