A Study Of Galcanezumab In Participants With Episodic Cluster Headache

Inclusion Criteria: * Have a diagnosis of cluster headache as defined by International Headache Society (IHS) International Classification of Headache Disorders (ICHD)-3 beta guidelines with a history of episodic cluster headache with at least two cluster periods lasting from 7 days to 1 year (when untreated) and separated by pain-free remission periods of \>=1 month. * Participants are able to distinguish cluster headache attacks from other headaches. Exclusion Criteria: * Current enrollment in or discontinuation within the last 30 days from, a clinical trial involving any investigational drug or device. * Current use or any prior exposure to any calcitonin-gene-related peptide (CGRP) antibody, any antibody to the CGRP receptor, or antibody to nerve growth factor (NGF). * Are taking indomethacin and/or are suspected of having another distinct trigeminal autonomic cephalalgia. * A history of migraine variants that could implicate or could be confused with ischemia. * Known hypersensitivity to multiple drugs, monoclonal antibodies or other therapeutic proteins. * A history or presence of other medical illness that indicates a medical problem that would preclude study participation. * Evidence of significant active or unstable psychiatric disease, in the opinion of the investigator. * Women who are pregnant or nursing.