The criteria for a migraine headache was adapted from the standard International Headache Society (IHS) International Classification of Headache Disorders (ICHD)-3 beta. The definition of a migraine headache was a headache with or without aura, of ≥30 minutes (min) duration, and with both ("A" and "B") required features from the IHS ICHD-3 beta definition. Required feature "A" includes at least 2 of the following headache characteristics: unilateral location, pulsatile quality, moderate or severe pain intensity, or aggravation by or causing avoidance of routine physical activity. Required feature "B" includes at least 1 of the following during the headache: nausea and/or vomiting, or photophobia and phonophobia.

All participants with a valid 28-day baseline assessment of migraine headache days who received at least 1 dose of study treatment and had evaluable postbaseline headache data.

A migraine attack was defined as beginning on any day a migraine headache day was recorded and ending when a migraine headache-free day occurred. The criteria was adapted from the standard IHS ICHD-3 beta definition. The definition of a migraine headache was a headache with or without aura, of ≥30 minutes (min) duration, and with both ("A" and "B") required features from the IHS ICHD-3 beta definition. Required feature "A" includes at least 2 of the following headache characteristics: unilateral location, pulsatile quality, moderate or severe pain intensity, or aggravation by or causing avoidance of routine physical activity. Required feature "B" includes at least 1 of the following during the headache: nausea and/or vomiting, or photophobia and phonophobia. Least Squares (LS) mean was calculated using mixed model repeated measures (MMRM) methodology with treatment, pooled investigative site, period, and treatment-by-period interaction, baseline and baseline-by-period interaction.

All participants with a valid 28-day baseline assessment of migraine headache days who received at least 1 dose of study treatment and had evaluable postbaseline headache data.

The criteria for a migraine headache was adapted from the standard International Headache Society (IHS) International Classification of Headache Disorders (ICHD)-3 beta definition. The definition of a migraine headache was a headache with or without aura, of ≥30 minutes (min) duration, and with both ("A" and "B") required features from the IHS ICHD-3 beta definition. Required feature "A" includes at least 2 of the following headache characteristics: unilateral location, pulsatile quality, moderate or severe pain intensity, or aggravation by or causing avoidance of routine physical activity. Required feature "B" includes at least 1 of the following during the headache: nausea and/or vomiting, or photophobia and phonophobia.

All participants with a valid 28-day baseline assessment of migraine headache days who received at least 1 dose of study treatment and had evaluable postbaseline headache data during the time period of analysis.

A migraine attack was defined as beginning on any day a migraine headache day was recorded and ending when a migraine headache-free day occurred. The criteria was adapted from the standard IHS ICHD-3 beta definition. The definition of a migraine headache was a headache with or without aura, of ≥30 minutes (min) duration, and with both ("A" and "B") required features from the IHS ICHD-3 beta definition. Required feature "A" includes at least 2 of the following headache characteristics: unilateral location, pulsatile quality, moderate or severe pain intensity, or aggravation by or causing avoidance of routine physical activity. Required feature "B" includes at least 1 of the following during the headache: nausea and/or vomiting, or photophobia and phonophobia. Least Squares (LS) means was determined by mixed model repeated measures (MMRM) methodology with treatment, pooled investigative site, period, and treatment-by-period interaction, baseline and baseline-by-period interaction.

All participants with a valid 28-day baseline assessment of migraine headache days who received at least 1 dose of study treatment and had evaluable postbaseline headache data.

Number of headache hours calculated as the total number of headache hours in a 28-day period on which a headache occurred. Least Squares (LS) means was determined by mixed model repeated measures (MMRM) methodology with treatment, pooled investigative site, period, and treatment-by-period interaction, baseline and baseline-by-period interaction.

All participants with a valid 28-day baseline assessment of migraine headache days who received at least 1 dose of study treatment and had evaluable postbaseline headache data.

MSQL consists of 14 questions across 3 dimensions (role function-restrictive, role function-preventive, and emotional function). All question values range from 1 to 6. Participants rated each item from 1 (none of the time) to 6 (all of the time). Since each item was presented as a negative statement, participant responses were recorded before item scores were calculated. Then, dimension scores were calculated as the sum of the recorded items for that specific dimension. Each dimension score was transformed into a score that ranged from 0 to 100. The transformation formula for the restrictive function = [(dimension score-7)*100]/35, for the preventive function = [(dimension score-4)*100]/20, and for the emotional function = [(dimension score-3)*100]/15. A lower score indicated a poorer quality of life associated with that domain. LS means was determined by Analysis of covariance (ANCOVA) with treatment, pooled investigative site and baseline.

All randomized participants who received at least 1 dose of study drug and have non-missing values at baseline and post-baseline value.

The HIT-6 consists of 6 questions to measure the impact of headaches on the participants ability to function on the job, at school, at home and in social situations. A score to each question will be assigned as follows: never - 6, rarely - 8, sometimes - 10, very often - 11, and always - 13. The composite score is calculated as the sum of the scores for all 6 questions, the total score ranges between 36 and 78 with higher total scores reflecting more severe impact of headaches. LS means was determined by ANCOVA with treatment, pooled investigative site and baseline.

All randomized participants who received at least 1 dose of study drug and have non-missing values at baseline and post-baseline value.

Blood serum concentrations of galcanezumab.

All randomized participants who received at least 1 dose of study drug with non-missing baseline and postbaseline measures for serum concentration of galcanezumab.

CGRP has been shown to be involved in the pathophysiology of migraine through dilation of cerebral and dural blood vessels, release of inflammatory mediators, and transmission of nociceptive (pain) information from intracranial blood vessels to the nervous system (Villalón and Olesen 2009). In migraineurs, serum concentrations of CGRP are significantly elevated during migraine attacks (Goadsby et al. 1990; Goadsby and Edvinsson 1993).

All randomized participants who received at least 1 dose of study drug with non-missing baseline and postbaseline measures for CGRP plasma concentration.

The percent of participants with treatment emergent Anti-drug Antibodies (ADA) were assessed at week 1 to 12. A participant was considered to have treatment-emergent Galcanezumab ADA if the participant had at least 1 titer that was treatment-emergent relative to baseline, defined as any of the following: A negative baseline ADA result and a subsequent positive post-baseline ADA result with a titer >=20; or a positive ADA results and a subsequent positive post-baseline ADA results with a 4-fold or greater increase in titer from the baseline measurement.

All randomized participants who received at least 1 dose of study drug with non-missing baseline and postbaseline ADA measures.

The C-SSRS captures the occurrence, severity, and frequency of suicide-related thoughts and behaviors during the assessment period. The scale includes suggested questions to solicit the type of information needed to determine if a suicide-related thought or behavior occurred. Some questions are binary responses (yes/no) and some are on a scale of 1 (low severity) to 5 (high severity). Suicidal behavior: a "yes" answer to any of 5 suicidal behavior questions: preparatory acts or behavior, aborted attempt, interrupted attempt, actual attempt, and completed suicide.

All randomized participants who received at least 1 dose of study drug and with non-missing baseline and postbaseline C-SSRS assessment.

Number of calendar days on which a headache lasts ≥4 hours which includes migraines, probable migraines (PM) and nonmigraines. Criteria for migraine headache (MH) was adapted from standard IHS ICHD-3 beta definition. It is defined as headache with or without aura, of ≥30 min duration, and with both ("A" and "B") required features from IHS ICHD-3 beta definition. Required feature "A" includes ≥2 of following headache characteristics: unilateral location, pulsatile quality, moderate or severe pain intensity, or aggravation by or causing avoidance of routine physical activity. Required feature "B" includes at least 1 of following during headache: nausea and/or vomiting, or photophobia and phonophobia. PM is headache with or without aura, but missing 1 feature needed to fulfill all criteria for MH. LS means were calculated using MMRM with treatment, pooled investigative site, period, and treatment-by-period interaction, baseline and baseline-by-period interaction.

All randomized participants with a valid 28-day baseline assessment of migraine headache days who received at least 1 dose of study treatment and had evaluable postbaseline headache data.

Number of calendar days on which headache lasts ≥4 hrs it includes migraines, PM & non-migraines. MH is headache with or without aura, of ≥30 min duration, and with both ("A" and "B") required features from IHS ICHD-3 beta definition. Required feature "A" includes ≥2 of following headache characteristics: unilateral location, pulsatile quality, moderate or severe pain intensity, or aggravation by or causing avoidance of routine physical activity. Required feature "B" includes at least 1 of following during headache: nausea &/or vomiting, or photophobia & phonophobia. PM is headache with or without aura, but missing 1 feature needed to fulfill all criteria for MH. Severity was measured via interactive voice response system questionnaire "What was the worst headache pain? For mild press 1. For moderate 2. For severe press 3". LSmean was calculated using MMRM with treatment, pooled investigative site, period, treatment-by-period interaction, baseline and baseline-by-period interaction.

All participants with a valid 28-day baseline assessment of migraine headache days who received at least 1 dose of study treatment and had evaluable postbaseline headache data.