Pain levels were assessed on a 4-point scale (none, mild, moderate, severe) using the electronic diary (eDiary). Pain freedom was defined as pain level of none.

MBS was reported as nausea, photophobia, or phonophobia at migraine onset using the eDiary. Symptom status (absent, present) was assessed post-dose using the eDiary separately for nausea, photophobia, and phonophobia. Freedom from MBS was defined as MBS reported at onset that was absent post-dose.

An AE was defined as any new untoward medical occurrence or worsening of a pre-existing medical condition on-treatment in a patient or clinical investigation participant administered an investigational (medicinal) product and that did not necessarily have a causal relationship with this treatment. An SAE was defined as any event that met any of the following 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; other important medical events that may not have resulted in death, be life-threatening, or required hospitalization, based upon appropriate medical judgment, they may have jeopardized the participant and may have required medical or surgical intervention.

Clinically significant laboratory abnormalities were defined as Grade 3 to 4 on-treatment laboratory test results according to numeric laboratory test criteria found in Common Technical Criteria for Adverse Events (CTCAE) Version 5.0 (2017) if available; otherwise, according to Division of Acquired Immune Deficiency Syndrome (DAIDS) Table for Grading the Severity of Adult and Pediatric Adverse Events Corrected Version 2.1 (2017) for Glucose, LDL-Cholesterol, Uric Acid, and Urinalysis. Laboratory test groups of clinical interest included hematology, serum chemistry, and urinalysis. Participants must have had a non-missing measurement in the on-treatment period to be included for a given parameter.