Galcanezumab effectiveness on comorbid cluster headache and chronic migraine: a prospective case series

Cluster headache (CH) and migraine are recurrent painful primary cephalalgies, typically with different clinical appearance and some shared features, such as unilateral pain, common triggers and response to triptans and/or monoclonal antibodies against the calcitonin gene-related peptide (CGRP) pathway. Common pathophysiological mechanisms are proposed in CH and migraine, including the role of the trigeminal-vascular system with its most representative neuropeptide, CGRP. Very few case series have been conducted so far investigating anti-CGRP treatments in patients with comorbid CH and migraine, and no cases have been reported which assess both CH and chronic migraine outcomes.

We describe 4 patients with both chronic migraine and cluster headache, with or without failure to preventive medications. Galcanezumab (240 mg loading dose, followed by 120 mg monthly) was used for at least a 3-month treatment, demonstrating improvement in both migraine and CH outcomes (i.e. migraine days, CH attacks, Headache Impact Test -6 item score, acute medications use), achieving sustained clinical benefit. No adverse events were reported.

Taking into account the role of CGRP in migraine and CH pathophysiology, a usually well-tolerated treatment with CGRP blockade could be a rationale-based option to treat patients with coexisting chronic migraine and cluster headache. Additional studies are needed to assess the role of anti-CGRP drugs in episodic and chronic CH treatment, as well as to establish correct timing and patient prerequisites to begin therapy.