Efficacy, Safety, and Tolerability of Atogepant for the Prevention of Chronic Migraine

Inclusion Criteria:

• At least a 1-year history of chronic migraine (CM) consistent with a diagnosisaccording to the International Classification of Headache Disorders, 3rd Edition (ICHD-3), 2018
• Age of the participant at the time of migraine onset < 50 years
• Confirmation of headache/migraine headache day frequency as follows:
• History of, on average, ≥ 15 headache days per month in the 3 months prior toVisit 1 in the opinion of the investigator AND
• >=15 headache days during the 4-week screening/baseline period per the electronicdiary (eDiary) AND
• >=8 days during the 4-week screening/baseline period that qualify as being amigraine day per the eDiary
• Participants must be using a medically acceptable and effective method of birthcontrol during the course of the entire study

Exclusion Criteria:

• Has a history of migraine, accompanied by diplopia or decreased level ofconsciousness, or retinal migraine
• Has a current diagnosis of new persistent daily headache, trigeminal autonomiccephalgia (eg, cluster headache), or painful cranial neuropathy
• History of an inadequate response to > 4 medications (2 of which have differentmechanisms of action) prescribed for the prevention of migraine
• Woman is pregnant, planning to become pregnant during the course of the study, orcurrently lactating. Women of childbearing potential must have a negative urinepregnancy test at Visit 1 and Visit 2.