A Study to Learn About the Long-term Safety of Rimegepant for the Acute Treatment of Migraine in Chinese Participants

Inclusion Criteria

At least a one-year history of migraines (with or without aura), consistent with a diagnosis according to the International Classification of Headache Disorders, 3rd edition beta version, including the following:

• Age of onset of migraines prior to 50 years of age
• Migraine attacks, on average, lasting 4 - 72 hours if untreated
• 6-18 migraine attacks of moderate or severe intensity per month within the last 3 months prior to the Screening Visit
• 6 or more migraine days requiring treatment during Observation Phase
• Ability to distinguish migraine attacks from tension/cluster headaches
• Subjects on prophylactic migraine medication are permitted to remain on therapy if the dose has been stable dose for at least 2 months prior to the Baseline Visit, and the dose is not expected to change during the course of the study. subjects who previously discontinued prophylactic migraine medication must have done so at least 5 half-lives of the prophylactic medication prior to the Screening Visit
• Subjects with contraindications for use of triptans may be included provided they meet all other study entry criteria

Age and Reproductive Status:

• Male or female subjects ≥ 18 years
• Women of childbearing potential (WOCBP) must voluntarily use 1 acceptable methods of contraception to avoid pregnancy and to minimize the risk of pregnancy from signing of informed consent through 28 days after study drug administration. WOCBP is defined in Section 12.3. No contraception methods are required for male subjects in this study.

Exclusion Criteria

Target Disease Exclusion:

• Subjects has a history of basilar migraine with brain stem aura or hemiplegic migraine

Medical History and Comorbidities:

• History of HIV disease
• Current evidence of poorly controlled, unstable, or recently diagnosed cardiovascular or cerebrovascular disease such as ischemic heart disease, coronary vasospasm, and cerebral ischemia. Myocardial infarction (MI), acute coronary syndrome (ACS), percutaneous coronary intervention (PCI), cardiac surgery, stroke, or transient ischemic attack (TIA) during 6 months prior to screening
• Poorly controlled hypertension (high blood pressure) or poorly controlled diabetes (but subjects with stable hypertension and/or diabetes for at least 3 months prior to screening may be included in the study). Blood pressure greater than 150 mmHg systolic or 100 mmHg diastolic after 10 minutes of rest is exclusionary
• Subjects with a current diagnosis of major depression or a major depressive episode within the last 12 months, other pain syndromes, psychiatric disorders, dementia, or significant neurological disorders (other than migraine) that, in the opinion of the investigator, might interfere with study assessments
• History of gastric or small intestinal surgery (including gastric bypass, gastric banding, gastric sleeve, gastric water ball, etc.) or diseases resulting in malabsorption
• Subject has a history or diagnosis of Gilibert's Syndrome or any other active hepatic or biliary disorder
• History or presence of significant and/or unstable medical conditions (e.g., history of congenital heart disease or cardiac arrhythmia, known suspected infection, hepatitis B or C or neoplasm) that, in the opinion of the investigator, would expose the subjects to undue risk of a significant adverse events (AE) or interfere with the assessment of safety or effectiveness during the trial
• History or evidence of alcohol or drug abuse within the past 12 months, or treatment for alcohol or drug abuse, or meeting Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V) criteria for any significant substance abuse disorder within the past 12 months prior to the Screening Visit
• Subjects should be excluded if they have a positive drug screen for drugs of abuse and are considered medically significant by the investigator, would compromise subject safety, or interfere with the interpretation of study results. In addi