A Long-Term Safety Study of Elismetrep (K-304) in the Acute Treatment of Migraine

Is a female who is pregnant, breast-feeding, or intends to become pregnant during the planned course of the study. Note: Participants must have a negative urine pregnancy result at the base study EoS/Visit 3 (i.e., pre-randomization for this study);

Has, at the time of the base study EoS/Visit 3, had any change in medical history or a laboratory finding since screening in the acute treatment study that in the opinion of the investigator renders the participant unsuitable for this study (e.g., development of a finding that would have precluded participation in the base acute treatment study);

Participant is at imminent risk of self-harm, based on clinical interview and responses on the Columbia Suicidality Severity Rating Scale (C-SSRS) taken during the base study E0S/Visit 3, or of harm to others in the opinion of the investigator. Participants must be excluded if they report suicidal ideation with intent, with or without a plan (i.e., Type 4 or 5 on the C-SSRS) in 'since last version' version of the C-SSRS;

Participant is currently in violation of study requirements for prohibited and permissible concomitant medications (not already specified in other criteria or is anticipated to violate these requirements during trial participation) as assessed for the base study E0S/Visit 3;