Erenumab, a monoclonal antibody acting on the calcitonin gene-related peptide (CGRP) receptor, is an effective and safe migraine-specific preventive drug. The use of migraine-specific preventive drugs paves the way for a novel method to study migraine pathogenesis. Migraine is a complex disorder with several genetic and epigenetic influence, including that of microRNA. Several microRNAs, including those of inflammation and of endothelial function, have high expression levels in subjects with migraine; however, the findings of the available studies are insufficient to provide epigenetic biomarkers for migraine. Besides, little evidence is available on the role of migraine preventive treatments in the expression of microRNA. The study aims at evaluating the expression profiles of microRNAs before and after erenumab treatment prescribed according to clinical indication. The study will include women with episodic or chronic migraine treated with erenumab 140 mg monthly according to the Summary of Product Characteristics and local reimbursement criteria. The study will compare the expression profile of microRNAs in women with episodic and chronic migraine; besides, it will investigate differences in migraine-associated microRNA expression according to age, migraine characteristics, pain intensity, response to erenumab, migraine-related impact and disability.

Inclusion Criteria:

• Women aged 25 to 50 years
• Chronic or episodic migraine with or without aura diagnosed according to the International Classification of Headache Disorders - 3rd edition
• Receiving a first prescription of erenumab for migraine prevention according to the Summary of Product Characteristics and local reimbursement criteria
• At least 1 year from migraine onset
• Provided informed consent

Exclusion Criteria:

• Headache other than migraine
• Prior exposure to erenumab or other monoclonal antibodies targeting CGRP or its receptor
• Use of any migraine preventive treatment in the last 60 days or 5 half-lives or 4 months if ever treated with botulinum toxin A
• Pregnant or nursing
• Body Mass Index <18 or >30 Kg/m2
• Heavy smoking (more than 20 cigarettes per day)
• Myocardial infarction, stroke, transient ischemic attack, unstable angina, or coronary artery bypass surgery or other revascularization procedures within 12 months prior to first visit
• Illicit drug abuse
• Major psychiatric disorders
• Infective or inflammatory diseases
• Any chronic medication prescribed for indications different from migraine within 60 days before study initiation