A Study to Learn About the Study Medicine Called Rimegepant in Adolescents With Frequent Migraine

Efficacy of rimegepant relative to placebo measured as the mean change from baseline in the number of acute migraine-specific medication days per month

Change in the use of acute migraine-specific medication days per month

Time frame: 12 Weeks

Efficacy of rimegepant relative to placebo measured the mean change from baseline in the number of headache days per month

Change in headache days per month

Time frame: 12 Weeks

Efficacy of rimegepant relative to placebo measured as the percentage of participants with at least 50% reduction from baseline in number of moderate or severe migraine days per month

Change in moderate or severe migraine days per month

Time frame: 12 weeks

Efficacy of rimegepant relative to placebo measured as the mean change from baseline in the Pediatric Quality of Life (PedsQL™) total score

Change in the Quality of Life

Time frame: 12 Weeks

Efficacy of rimegepant relative to placebo measure as the mean change from baseline in the number of acute headache medication days per month, and acute migraine-specific medication days per month

Change in headache and migraine rescue medication(s) used

Time frame: 12 Weeks

Safety of rimegepant relative to placebo, and safety of rimegepant given for a long period of time measured as the number and percentage of participants with adverse event by severity and overall

Safety and tolerability of the study drug

Time frame: Up to 15 months

Safety of rimegepant relative to placebo, and safety of rimegepant given for long period of time measured as the number and percentage of participants with liver-related adverse event and action taken

Safety monitoring of adverse events of special interest

Time frame: Up to 15 Months

Efficacy of rimegepant relative to placebo measured as mean change from baseline in the PedMIDAS total score

Change in the Quality of Life

Time frame: 12 Weeks