A treatment-emergent AE was defined as any on-treatment untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. A summary of non-serious AEs and all serious AEs, regardless of causality is located in Reported AE section.

The APTS included all participants who received infusion with eptinezumab.

Participants counted as converting from cCH to eCH if they had no CH attacks for at least 3 months.

The Full Analysis Set (FAS) included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks.

Abortive therapy was defined as oxygen and/or triptans, where it counted as 2 times if oxygen and triptans were used for the same attack.

The FAS included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks. Here, "Overall Number of Participants Analyzed" is the number of participants evaluable for this outcome measure, and "Number analyzed" is the number of participants evaluable at each specified time point.

The FAS included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks. Here, "Overall Number of Participants Analyzed" is the number of participants evaluable for this outcome measure, and "Number analyzed" is the number of participants evaluable at each specified time point.

The FAS included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks. Here, "Overall Number of Participants Analyzed" is the number of participants evaluable for this outcome measure, and "Number analyzed" is the number of participants evaluable at each specified time point.

The participant completed a CH eDiary, daily, and record for each day/week whether he/she had any CH attacks.

The FAS included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks. Here, "Overall Number of Participants Analyzed" is the number of participants evaluable for this outcome measure, and "Number analyzed" is the number of participants evaluable at each specified time point.

The average of the estimated change from baseline in the number of weekly attacks across the first 4 weeks after the infusion is shown.

The FAS included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks. Here, "Overall Number of Participants Analyzed" is the number of participants evaluable for this outcome measure.

The average of the estimated change from baseline in the number of weekly attacks across the first 2 weeks after the infusion is shown.

The FAS included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks. Here, "Overall Number of Participants Analyzed" is the number of participants evaluable for this outcome measure.

The average of the estimated change from baseline in the number of monthly attacks across the first 12 months after the infusion is shown.

The FAS included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks. Here, "Overall Number of Participants Analyzed" is the number of participants evaluable for this outcome measure.

The severity of pain for each attack was rated on an ordinal scale that ranged from 0 to 4 with higher scores indicating more headache pain (headache pain ratings: 0 = none/barely any pain; 1 = mild; 2 = moderate; 3 = severe; 4 = excruciating).

The FAS included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks. Here, "Overall Number of Participants Analyzed" is the number of participants evaluable for this outcome measure, and "Number analyzed" is the number of participants evaluable at each specified time point.

The FAS included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks. Here, "Overall Number of Participants Analyzed" is the number of participants evaluable for this outcome measure, and "Number analyzed" is the number of participants evaluable at each specified time point.

The FAS included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks. Here, "Overall Number of Participants Analyzed" is the number of participants evaluable for this outcome measure, and "Number analyzed" is the number of participants evaluable at each specified time point.

The FAS included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks. Here, "Overall Number of Participants Analyzed" is the number of participants evaluable for this outcome measure, and "Number analyzed" is the number of participants evaluable at each specified time point.

Participants counted as being in remission if they had no cluster headache attacks for at least 1 month.

The FAS included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks. Here, "Overall Number of Participants Analyzed" is the number of participants evaluable for this outcome measure, and "Number analyzed" is the number of participants evaluable at each specified time point.

The FAS included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks. Here, "Overall Number of Participants Analyzed" is the number of participants evaluable for this outcome measure, and "Number analyzed" is the number of participants evaluable at each specified time point.

The FAS included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks. Here, "Overall Number of Participants Analyzed" is the number of participants evaluable for this outcome measure, and "Number analyzed" is the number of participants evaluable at each specified time point.

The FAS included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks. Here, "Overall Number of Participants Analyzed" is the number of participants evaluable for this outcome measure, and "Number analyzed" is the number of participants evaluable at each specified time point.

The FAS included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks. Here, "Overall Number of Participants Analyzed" is the number of participants evaluable for this outcome measure.

Transitional treatments were defined as greater occipital nerve (GON) block or oral steroids.

The FAS included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks.

The PGIC is a patient-reported measure of improvement in pain sensation and quality of life scored on a scale from 1 (very much improved) to 7 (very much worse). Lower scores indicate better health status.

The FAS included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks. Here, "Overall Number of Participants Analyzed" is the number of participants evaluable for this outcome measure, and "Number analyzed" is the number of participants evaluable at each specified time point.

The SIS is a patient-reported clinical outcome assessment used to assess quality of life resulting from sleep disturbance. The SIS questionnaire includes 35 items belonging to 7 domains to assess sleep impact on: daily activities; emotional well-being; emotional impact; energy/fatigue; social well-being; mental fatigue; and satisfaction with sleep. Each item, for 6 out of the 7 domains, is rated on a 5-point scale ranging from 1 (always or all of the time) to 5 (never or none of the time), whereas satisfaction with sleep is rated on a 5-point scale ranging from 1 (very satisfied) to 5 (very dissatisfied). Each domain yields a score ranging from 0 to 100, which is presented here. A higher score for Daily Activities, Emotional Well-being, Emotional Impact, Energy/Fatigue, Social Well-being, and Mental Fatigue indicates better quality of life. A lower score for Satisfaction with Sleep indicates a higher quality of life.

The FAS included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks. Here, "Overall Number of Participants Analyzed" is the number of participants evaluable for this outcome measure, and "Number analyzed" is the number of participants evaluable for each specified category.

The EQ-5D-5L is a patient-reported assessment designed to measure the participant's well-being. It consists of 5 descriptive items (mobility, self-care, usual activities, pain/discomfort, and depression/anxiety). Each descriptive item is rated on a 5-point index ranging from 1 (no problems) to 5 (extreme problems).

The FAS included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks. Here, "Overall Number of Participants Analyzed" is the number of participants evaluable for this outcome measure, and "Number analyzed" is the number of participants evaluable for each specified category.

The EQ-5D-5L VAS is a participant-reported assessment designed to measure the participant's well-being and ranges from 0 (worst imaginable health state) to 100 (best imaginable health state).

The FAS included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks. Here, "Overall Number of Participants Analyzed" is the number of participants evaluable for this outcome measure, and "Number analyzed" is the number of participants evaluable at each specified time point.

The WPAI:GH2.0 is a patient self-rated clinical outcome assessment designed to provide a quantitative measure of the work productivity and activity impairment due to a health condition. The WPAI:GH2.0 assesses activities over the preceding 7 days and consists of 6 items: 1 item assesses employment (yes/no); 3 items assess the number of hours worked, the number of hours missed from work due to the participant's condition, or due to other reasons; and 2 visual numerical scales assess how much the participant's condition affects his/her productivity at work and his/her ability to complete normal daily activities. Each item (Absenteeism, Presenteeism, Work Productivity Loss, Activity Impairment) was calculated into an impairment percentage ranging from 0 to 100%, with higher numbers indicating greater impairment and less productivity (i.e. worse outcomes). Change from baseline for each item is shown here.

The FAS included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks. Here, "Overall Number of Participants Analyzed" is the number of participants evaluable for this outcome measure, and "Number analyzed" is the number of participants evaluable for each specified category.

Number of participants who visited a family doctor/general practitioner has been reported.

The FAS included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks. Here, "Overall Number of Participants Analyzed" is the number of participants evaluable for this outcome measure, and "Number analyzed" is the number of participants evaluable for each specified category.

Number of participants who visited a specialist has been reported.

The FAS included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks. Here, "Overall Number of Participants Analyzed" is the number of participants evaluable for this outcome measure, and "Number analyzed" is the number of participants evaluable for each specified category.

Number of participants who visited an emergency department due to CH has been reported.

The FAS included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks. Here, "Overall Number of Participants Analyzed" is the number of participants evaluable for this outcome measure, and "Number analyzed" is the number of participants evaluable for each specified category.

Number of participants admitted to the hospital due to CH has been reported.

The FAS included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks. Here, "Overall Number of Participants Analyzed" is the number of participants evaluable for this outcome measure, and "Number analyzed" is the number of participants evaluable for each specified category.

Number of participants who had overnight hospital stays due to CH has been reported.

The FAS included all participants in the APTS who had a valid assessment of the baseline number of weekly attacks and a post-baseline assessment of the number of weekly attacks. Here, "Overall Number of Participants Analyzed" is the number of participants evaluable for this outcome measure, and "Number analyzed" is the number of participants evaluable for each specified category.