A Study to Learn About the Safety and Effects of Rimegepant to Prevent Migraine in Chinese Subjects.

A MD was defined as any calendar day participant experienced a qualified migraine headache(onset,continuation,or recurrence),per eDiary. A qualified migraine headache was defined as a migraine with/without aura,lasted for >=30 minutes with >=2 pain features(unilateral location,pulsating quality [throbbing], moderate/severe pain intensity, aggravated by or caused avoidance of routine physical activity [e.g. walking/climbing stairs]) and/or with >=1 of the following associated symptoms(nausea and/or vomiting, both photophobia and phonophobia).The number of MD per month was prorated to 28 days and derived as: OP: 28*[total number of MD in OP analysis period]/(total number of efficacy data days in OP analysis period), monthly (4-week interval) on-DBT efficacy analysis period: 28*(total number of MD in month)/(total number of efficacy data days in month),overall DBT in on-DBT efficacy analysis period:28*(total number of MD through month 3)/(total no .of efficacy data days through month 3).

A MD was defined as any calendar day participant experienced a qualified migraine headache(onset,continuation,or recurrence),per eDiary. A qualified migraine headache was defined as a migraine with/without aura,lasted for >=30 minutes with >=2 pain features (unilateral location,pulsating quality[throbbing],moderate/severe pain intensity,aggravated by or caused avoidance of routine physical activity[e.g. walking/climbing stairs]) and/or with >=1 of the following associated symptoms (nausea and/or vomiting, both photophobia and phonophobia).The number of MD per month was prorated to 28 days and derived as:OP:28*[total number of MD in OP analysis period]/(total number of efficacy data days in OP analysis period), monthly (4-week interval) on-DBT efficacy analysis period: 28*(total number of MD in month)/(total number of efficacy data days in month), overall DBT in on-DBT efficacy analysis period:28*(total number of MD through month 3)/(total number of efficacy data days through month 3).

A MD was defined as any calendar day participant experienced a qualified migraine headache(onset,continuation,or recurrence),per eDiary. A qualified migraine headache was defined as a migraine with/without aura,lasted for >=30 minutes with >=2 pain features (unilateral location,pulsating quality[throbbing],moderate/severe pain intensity,aggravated by or caused avoidance of routine physical activity [e.g. walking/climbing stairs]) and/or with >=1 of the following associated symptoms (nausea and/or vomiting, both photophobia and phonophobia).The number of MD per month was prorated to 28 days and derived as:OP:28*[total number of MD in OP analysis period]/(total number of efficacy data days in OP analysis period), monthly (4-week interval) on-DBT efficacy analysis period: 28*(total number of MD in month)/(total number of efficacy data days in month),overall DBT in on-DBT efficacy analysis period:28*(total number of MD through month 3)/(total number of efficacy data days through month 3).

MSQoL:14-item instrument validated in 3 domains:restrictive role function,preventative role function and emotional function.Role function-restrictive domain consisted of 7 items that described how migraine limits one's daily social and work-related activities.Participants were required to respond to items using a 6-point scale ranging from 1-6, where 1=none of the time,2=little bit of the time,3=some of the time,4=good bit of the time,5=most of the time and 6=all of the time.Item scores were recorded using(7-original score).Raw dimension scores for restrictive role function domain were computed as a sum of recorded item scores(7-42) and rescaled from 0-100 scale such that lowest score(0) indicated poor quality of life(QOL) and highest scores(100) indicated better QOL.Change from baseline was calculated as MSQoL role function-restrictive domain score at Week 12 of DBT phase minus MSQoL role function-restrictive domain score at baseline.Data collected on Day 1 was referred to Baseline.

Acute migraine-specific medication day was defined as any calendar day during which the participant took a migraine-specific medication (triptan). Acute migraine medication days were defined as either acute migraine-specific medication day or migraine day with "yes" response to the question about taking other medications to treat headache or aura. The number of migraine day per month was prorated to 28 days and derived as: OP: 28*[total number of migraine day in the OP analysis period]/(total number of efficacy data days in the OP analysis period), monthly (i.e., 4-week interval) in the on-DBT efficacy analysis period: 28*(total number of migraine day in the month)/(total number of efficacy data days in the month), overall DBT in the on-DBT efficacy analysis period: 28*(total number of migraine day through month 3)/(total number of efficacy data days through month 3).

An AE was defined as any new untoward medical occurrence or worsening of a pre-existing medical condition in a participant or clinical investigation participant administered an investigational (medicinal) product and that did not necessarily have a causal relationship with this treatment. AEs were graded per the common terminology criteria for adverse events (CTCAE) as grade 1 indicates mild AE, grade 2 indicates moderate AE, grade 3 indicates severe AE, grade 4 indicates life-threatening consequences and urgent intervention, and grade 5 indicates death related to AE. Number of participants who had grade 3 or 4 AEs were reported in this outcome measure.

An SAE was any event that met any of the criteria: death, life-threatening, inpatient hospitalization or prolongation of existing hospitalization, persistent or significant disability/incapacity, congenital anomaly/birth defect in the offspring of a participant who received rimegepant were considered an important medical event.

An AE was defined as any new untoward medical occurrence or worsening of a pre-existing medical condition in a participant or clinical investigation participant administered an investigational (medicinal) product and that does not necessarily have a causal relationship with this treatment. In this outcome measure participants with AEs leading to discontinuation of study intervention during the DBT phase were reported.

Laboratory test included hematology (hemoglobin, lymphocytes, white blood cell count [high, low], neutrophils and platelets), serum chemistry (alkaline phosphatase [ALP], alanine aminotransferase [ALT], aspartate aminotransferase [AST], albumin, bilirubin, creatine kinase [CK], calcium [high, low], glucose fasting and non-fasting [high, low], cholesterol [total], glucose [low], creatinine, LDL cholesterol, potassium, sodium [high, low], triglycerides, uric acid [urate] and estimated glomerular filtration rate [eGFR] modification of diet in renal disease [MDRD]) and urinalysis (urine glucose and urine protein). Laboratory abnormalities were graded according to CTCAE as grade 3 indicates severe AE, grade 4 indicates life-threatening consequences and urgent intervention. Number of participants who had non-zero grade 3 to 4 laboratory test abnormalities were reported in this outcome measure.

An AE was defined as any new untoward medical occurrence or worsening of a pre-existing medical condition in a participant or clinical investigation participant administered an investigational (medicinal) product and that did not necessarily have a causal relationship with this treatment. AEs were graded per the CTCAE as grade 1 indicates mild AE, grade 2 indicates moderate AE, grade 3 indicates severe AE, grade 4 indicates life-threatening consequences and urgent intervention, and grade 5 indicates death related to AE. Number of participants who had grade 3 or 4 AEs were reported in this outcome measure.

An SAE was any event that met any of the criteria: death, life-threatening, inpatient hospitalization or prolongation of existing hospitalization, persistent or significant disability/incapacity, congenital anomaly/birth defect in the offspring of a participant who received rimegepant were considered an important medical event.

An AE was defined as any new untoward medical occurrence or worsening of a pre-existing medical condition in a participant or clinical investigation participant administered an investigational (medicinal) product and that does not necessarily have a causal relationship with this treatment. In this outcome measure participants with AEs leading to discontinuation of study intervention during the OLE phase were reported.

Laboratory test included hematology (hemoglobin, lymphocytes, white blood cell count [high, low], neutrophils and platelets), serum chemistry (ALP, ALT, AST, albumin, bilirubin, CK, calcium [high, low], glucose fasting and non-fasting [high, low], cholesterol [total], glucose [low], creatinine, LDL cholesterol, potassium, sodium [high, low], triglycerides, uric acid [urate] and eGFR MDRD) and urinalysis (urine glucose and urine protein). Laboratory abnormalities were graded according to CTCAE as grade 3 indicates severe AE, grade 4 indicates life-threatening consequences and urgent intervention. Number of participants who had non-zero grade 3 to 4 laboratory test abnormalities were reported in this outcome measure.

Number of participants with ALT or AST elevations >3*ULN concurrent with TBL elevations >2*ULN in DBT phase were reported in this outcome measure.

Number of participants with ALT or AST elevations >3*ULN concurrent with TBL elevations >2*ULN in OLE phase were reported in this outcome measure.

An AE was defined as any new untoward medical occurrence or worsening of a pre-existing medical condition in a participant or clinical investigation participant administered an investigational (medicinal) product and that does not necessarily have a causal relationship with this treatment. In this outcome measure participants with hepatic-related AEs during the DBT phase were reported.

An AE was defined as any new untoward medical occurrence or worsening of a pre-existing medical condition in a participant or clinical investigation participant administered an investigational (medicinal) product and that does not necessarily have a causal relationship with this treatment. In this outcome measure participants with hepatic-related AEs leading to discontinuation of study intervention during the DBT phase were reported.

An AE was defined as any new untoward medical occurrence or worsening of a pre-existing medical condition in a participant or clinical investigation participant administered an investigational (medicinal) product and that does not necessarily have a causal relationship with this treatment. In this outcome measure participants with hepatic-related AEs during the OLE phase were reported.

An AE was defined as any new untoward medical occurrence or worsening of a pre-existing medical condition in a participant or clinical investigation participant administered an investigational (medicinal) product and that does not necessarily have a causal relationship with this treatment. In this outcome measure participants with hepatic-related AEs leading to discontinuation of study intervention during the OLE phase were reported.