Imaging the Migraine Brain Pre- and Post-Erenumab

Inclusion Criteria

• 18-65 years of age
• Episodic migraine (with or without aura) or chronic migraine according to the diagnostic criteria included within the International Classification of Headache Disorders 3 (ICHD-3)
• 6-25 migraine days per month on average over the 3 months prior to screening, confirmed by run-in phase prospective data collection
• Duration since migraine onset of at least 12 months prior to screening based on medical records and/or patient self-report

Exclusion Criteria

• Older than 50 years of age at migraine onset
• History of cluster headache or hemiplegic migraine
• Continuous headache pain (i.e. no pain-free periods of any duration during the one month before screening)
• Opioid- or butalbital-containing analgesics on 6 or more days per month during the 2 months prior to the start of the baseline phase
• History of major psychiatric disorder such as schizophrenia and bipolar disorder
• History or evidence of any unstable or clinically significant medical condition, that in the opinion of the investigator, would pose a risk to subject safety or interfere with the study evaluation, procedures, or completion
• No therapeutic response in migraine prevention after an adequate therapeutic trial of 4 or more of the following medication categories: Category 1- divalproex sodium, sodium valproate; Category 2- topiramate; Category 3- beta-blockers; Category 4- tricyclic antidepressants; Category 5- venlafaxine or desvenlafaxine, duloxetine or milnacipran; Category 6- flunarizine, verapamil; Category 7- lisinopril, candesartan; Category 8- botulinum toxin. No therapeutic response is defined as no reduction in headache frequency, duration, or severity after administration of the medication for at least 6 weeks at the generally accepted therapeutic dose(s) based on the investigator's assessment. Lack of sustained response to a medication and failure to tolerate a therapeutic dose are not considered to be "no therapeutic response".
• Concomitant use of 3 or more of the following medications for migraine prevention within 2 months before the start of the baseline phase or throughout the study: divalproex sodium, sodium valproate, topiramate, carbamazepine, gabapentin, beta-blockers, tricyclic antidepressants, venlafaxine, desvenlafaxine, duloxetine, milnacipran, flunarizine, verapamil, lomerizine, lisinopril, candesartan, clonidine, guanfacine, cyproheptadine, methysergide, pizotifen, butterbur, feverfew, magnesium (at least 600 mg per day), riboflavin (at least 100 mg per day). Use of up to two medications is permitted as long as the dose has been stable for at least 2 months before the start of the run-in phase and during the study.
• Botulinum toxin (in the head and/or neck region) within 4 months before the start of the baseline phase and throughout the study
• Ergotamine derivatives, steroids, and triptans used for migraine prophylaxis within 2 months before the start of the baseline phase and throughout the study
• Procedures (e.g. nerve blocks) used for migraine prophylaxis within 2 months before the start of the baseline phase and throughout the study
• History of myocardial infarction, stroke, transient ischemic attack, unstable angina, coronary artery bypass surgery, or other revascularization procedures within 12 months prior to screening.
• Contraindications to MRI including, but not limited to: Metal implants, aneurysm clips, severe claustrophobia, implanted electronic devices, insulin or infusion pump, cochlear/otologic/ear implant, non-removable prosthesis, implanted shunts/catheters, certain intrauterine devices, tattooed makeup, body piercings that cannot be removed, metal fragments, wire sutures or metal staples.
• Factors that Reduce MR Image Quality and Interpretability: dental braces or other non-removable devices (e.g. retainers); prior brain surgery; known brain MRI abnormality that in the investigator's opinion will significantly impact MRI data
• Sensory disorders that in the investig