Inclusion Criteria:

• The patient has episodic cluster headache, as defined by IHS ICHD-3 classification, with a documented history of eCH of at least 12 months prior to Screening Visit 1.
• The patient has a prior history of cluster period(s) lasting 6 weeks or longer.
• The patient is able to distinguish cluster headache attacks from other headaches (i.e. tension-type headaches, migraine).
• The patient is, at Screening Visit 2, in cluster headache bout, characterized by the presence of at least one typical cluster headache attack, that started not later than 1 week prior to Screening Visit 2. In the opinion of the investigator the cluster headache bout is likely to continue for at least another 6 weeks based on prior cluster period history. Under exceptional circumstances, when a patient is able to attend Screening Visit 2 only during the second week after the first typical cluster headache attack, the possibility to enroll this patient in the study will be discussed with the investigator and the decision will be taken in the context of known history of typical duration of the bout for the individual patient.
• The patient has during Screening Period 2 based on prospectively collected information in the eDiary a weekly cluster headache attack frequency of a (this requirement should not be shared with the patient):
  • minimum of at least 7 total cluster headache attacks out of the 7-day Screening Period 2;
  • maximum of 56 cluster headache attacks out of the 7-day Screening Period 2.
• The patient has an adequately documented record or reliable history of previous acute and preventive medication use for eCH, for at least 12 months prior to Screening Visit 1.
• The patient has demonstrated compliance with the eDiary by entry of data for at least 6 of the 7 days of Screening Period 2.
• The patient has had a medical history of cluster headache from < 50 years of age.
• The patient is aged ≥ 18 and ≤ 75 years at Screening Visit 1.

Exclusion Criteria:

• The patient has experienced failure on a previous treatment targeting the calcitonin gene-related peptide (CGRP) pathway (anti-CGRP mAbs and gepants).
• The patient has confounding and clinically significant pain syndromes (for example, fibromyalgia, complex regional pain syndrome).
• The patient has a history or diagnosis of hypnic headache, hemicrania continua, new daily persistent headache, chronic migraine or unusual migraine subtypes such as hemiplegic migraine (sporadic and familial), recurrent painful ophthalmoplegic neuropathy, migraine with brainstem aura and migraine with neurological accompaniments that are not typical of migraine aura (diplopia, altered consciousness, or long duration).
• Patients with a lifetime history of psychosis, bipolar mania, or dementia are excluded. Patients with other psychiatric conditions whose symptoms are not controlled or who have not been adequately treated for a minimum of 6 months prior to Screening Visit 2 are also excluded.
• The patient has attempted suicide or is, at Screening Visit 2, at significant risk of suicide (either in the opinion of the investigator or defined, using the C-SSRS, as the patient answering: "yes" to suicidal ideation questions 4 or 5 or answering: "yes" to suicidal behaviour within the past month). Patients who do not meet this criterion, but who are considered by the investigator to be at significant risk for suicide, are excluded.
• The patient has a history of clinically significant cardiovascular disease, including uncontrolled hypertension, ischaemia or thromboembolic events (for example, cerebrovascular accident, deep vein thrombosis, or pulmonary embolism).