A Study With Eptinezumab in Children and Adolescents (6 to 17 Years) With Chronic or Episodic Migraine

This is an extension study for participants aged 6 to 17 with migraine who completed either studies 19356A (NCT04965675) (chronic migraine \[CM\] study in adolescents) or 19357A (episodic migraine \[EM\] study in children and adolescents). All participants who complete the Week 12 visit of the respective lead-in study will be offered participation in this open-label extension (OLE) study, unless there is a safety concern precluding a participant's participation in the study. Participants originally randomized to 100 milligrams (mg) (weight adjusted) in the double-blind lead-in study (Study 19356A or Study 19357A) will continue on the same dose (100 mg, weight adjusted) in the OLE study. Participants randomized to the 300 mg dose (weight adjusted) in the double-blind lead-in study will continue on 300 mg (weight adjusted) in the OLE study. Participants who were assigned to placebo in the double-blind lead-in study will be randomly allocated to one of the two treatment groups: eptinezumab 100 mg (weight adjusted) or eptinezumab 300 mg (weight adjusted) with a ratio of 1:1.