A Phase 3, Multicenter, Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Study to Evaluate the Efficacy, Safety, and Tolerability of Atogepant for the Prevention of Chronic Migraine (Progress)

INTERVENTION: Intervention name : Atogepant INN of the intervention : ‐ Dosage And administration of the intervention : Atogepant 30mg (Tablet, taken twice daly) Atogepant 60mg (Tablet, taken once daly) Control intervention name : Placebo INN of the control intervention : ‐ Dosage And administration of the control intervention : Placebo (Tablet, taken twice daily) CONDITION: Chronic Migraine PRIMARY OUTCOME: efficacy; Change from baseline in mean monthly migraine days across the treatment period SECONDARY OUTCOME: efficacy; ‐ Change from baseline in mean monthly headache days across the 12‐week treatment period; ‐ Change from baseline in mean monthly acute medication use days across the 12‐week treatment period; ‐ Proportion of participants with at least a 50% reduction in mean monthly migraine days across the 12‐week treatment period; ‐ Change from baseline in MSQ v2.1 Role Function‐Restrictive domain score at Week 12; ‐ Change from baseline in mean AIM‐D monthly functioning and activity impairment score across the 12‐week treatment period INCLUSION CRITERIA: ‐ At least a 1‐year history of CM consistent with a diagnosis according to the 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 to Visit 1 in the opinion of the investigator AND ‐ >= 15 headache days during the 4‐week screening/baseline period per the electronic diary (eDiary) AND ‐ >= 8 days during the 4‐week screening/baseline period that qualify as being a migraine day per the eDiary ‐ Participants must be using a medically acceptable and effective method of birth control during the course of the entire study