['chronic cluster headache']
['galcanezumab 300 mg', 'placebo']

        Inclusion Criteria:

          -  Participants with a history of chronic cluster headache occurring without a remission
             period, or with remissions lasting <1 month, for at least 1 year.

          -  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.
      