Vestibular migraine (VM) is a distinct subtype of migraine that causes episodic vertigo/dizziness, sometimes with headache, and sometimes without. However, unlike traditional migraines, patients generally seek out care because of dizziness, and not because of headache. Therefore, these patients are cared for by a variety of providers who treat dizziness, including otolaryngologists and neurologists. Lifetime prevalence of VM in the general population is estimated to be 2.7%, and at least 10% of patients in a tertiary care vestibular clinic have VM. Furthermore, VM has been shown to decrease quality of life in multiple domains, including overall health, mental health, and emotional health. Since testing and imaging are usually normal, diagnosis can only be made on clinical grounds. Recently, consensus criteria for diagnosis was published by the Barany Society and the International Classification of Headache Disorders.

Galcanezumab is a calcitonin gene related peptide (CGRP) antagonist that has been approved by the FDA for treatment of episodic and chronic migraine. Its effects with regards to VM have not been formally studied. However, there is ample evidence to suggest that aberrant trigeminovascular inflammation may be integral to the pathophysiology of VM, similar to migraine in general.

This pilot study will be a single center, randomized double-blinded placebo-controlled trial comparing galcanezumab to placebo for treatment of VM. Screening data will be reviewed to determine subject eligibility. Participants who meet all inclusion criteria and none of the exclusion criteria will be entered into the study. Participants in the galcanezumab arm will receive 240 mg via subcutaneous injection with a pre-loaded syringe at month 1, followed by 120 mg at month 2, and 120 mg at month 3. Those in the placebo arms will receive subcutaneous injections at the same time intervals of placebo. Randomization will occur through the hospital research pharmacy. Allocation concealment will be ensured; study participants will be given an envelope from a folder of sequentially ordered identical envelopes that will contain study instructions and the allocated drug. The master file linking study ID with allocation will be created by a third party and kept secret until after data analysis is complete. This will ensure that both providers and participants are adequately blinded. Blocking will be used in increments of 10 subjects to ensure equitable distribution of subjects into the two treatment arms. In addition, stratification by sex and definite versus probable vestibular migraine status will be used to ensure equal allocation. Total duration of subject participation will be five months. Total duration of the study is expected to be 2 years.

Data collection will be performed by the clinical research coordinator during each study visit. This data will be entered into the REDCap database by the research coordinator. VM- Patient Assessment Tool and Handicap Inventory (VM-PATHI), dizziness handicap inventory (DHI), General Anxiety Disorder-7 (GAD-7), Patient Health Questionnaire-9 (PHQ-9), Patient-Reported Outcomes Measurement Information System Short Form (PROMIS SF) v1.1- Global Health, and Headache Impact Test-6 (HIT-6) will be administered electronically via REDCap to the subject during the study visit.

There will be no stopping rules for this trial, given the short duration of the study. Each adverse effect and serious adverse effect will be reviewed by the data safety monitoring team, and subjects may be unblinded and/or the study will be stopped early for serious safety concerns.