Study of Oral Atogepant When Added to OnabotulinumtoxinA (BOTOX) to Assess Adverse Events and Change in Disease Activity in Adult Participants With Chronic Migraine

Primary Outcome Measures

1. Number of Participants With Adverse Events (AEs)
   An adverse event (AE) is defined as any untoward medical occurrence in a patient or clinical investigation participant administered a pharmaceutical product which does not necessarily have a causal relationship with this treatment. The investigator assesses the relationship of each event to the use of study drug. A serious adverse event (SAE) is an event that results in death, is life-threatening, requires or prolongs hospitalization, results in a congenital anomaly, persistent or significant disability/incapacity or is an important medical event that, based on medical judgment, may jeopardize the participant and may require medical or surgical intervention to prevent any of the outcomes listed above. Treatment-emergent adverse events/treatment-emergent serious adverse events (TEAEs/TESAEs) are defined as any event that began or worsened in severity on or after the first dose of study drug.
2. Percentage of Participants With Potentially Clinically Significant (PCS) Laboratory Values (Chemistry, Hematology, Urinalysis) as Assessed by the Investigator
   Clinical laboratory test values are considered PCS if they meet either the lower-limit or higher-limit PCS criteria defined in the categories below. The percentage of participants with PCS laboratory values are summarized for hematology, chemistry, and urinalysis. Glomerular Filtration Rate (GFR) is a clinical measurement that calculates how many milliliters of blood the kidneys filter every second. Glucose, Urinalysis: At least 1+ indicates that the urine contains an increased concentration of sugar. Protein, Urinalysis: At least 1+ indicates that the urine contains an increased concentration of protein.
3. Percentage of Participants With Potentially Clinically Significant (PCS) Vital Sign Measurements as Assessed by the Investigator
   Potentially Clinically Significant post-Baseline vital sign values are summarized for categories: systolic and diastolic blood pressures \[sitting\], pulse rate \[sitting\], and weight. Number of participants with non-PCS baseline values who met the PCS criterion at least once post-baseline are reported.
4. Percentage of Participants With Most Severe Suicidal Ideation and Suicidal Behavior as Assessed by the Columbia-Suicide Severity Rating Scale (C-SSRS) During the Open-Label Treatment Period
   The C-SSRS is a clinician-rated instrument that reports the severity of both suicidal ideation and behavior. Suicidal ideation is classified on a 5-item scale: 1 (wish to be dead), 2 (nonspecific active suicidal thoughts), 3 (active suicidal ideation with any methods \[not plan\] without intent to act), 4 (active suicidal ideation with some intent to act, without specific plan), and 5 (active suicidal ideation with specific plan and intent). Suicidal behavior is classified on a 5-item scale: 0 (no suicidal behavior), 1 (preparatory acts or behavior), 2 (aborted attempt), 3 (interrupted attempt), and 4 (actual attempt). More than 1 classification can be selected provided they represent separate episodes. (Minimum total score 0, maximum total score 5; higher total scores indicate more suicidal ideation and/or suicidal behavior).
5. Percentage of Participants With Potentially Clinically Significant (PCS) Electrocardiograms (ECGs) Findings as Assessed by the Investigator
   12-lead ECGs were performed at select study visits.