Lack of funding to support the trial.

Researchers are trying to find out more about the side effects of fremanezumab when treating patients with Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) for migraine headaches.

Subjects will receive 4 to 20 weeks of placebo injections followed by 12 weeks of monthly administered fremanezumab by subcutaneous injection (225 mg split four weeks apart for 12 weeks). Following completion of the 12 weeks of therapy, the participant will return to placebo for the washout period. Both the patient and the investigator will be blinded to the timing of transition to and from placebo and the transition to and from fremanezumab.

Inclusion Criteria

• Age 18 to 70 years old
• English speaking
• Diagnosis of CADASIL confirmed by presence of a pathogenic NOTCH3 gene mutation
• Diagnosis of migraine for at least 12 months and diagnosis of chronic migraine for at least 28 days according to the International Classification of Headache Disorders
• MIDAS score of >10 points
• Ability to provide written informed consent

Exclusion Criteria

• History of ischemic stroke within 4 weeks of screening assessment
• Screening blood pressure >150 mm Hg
• Use of onabotulinum toxin A 4 months prior to trial or other injectable/stimulatory/magnetic method of headache control
• Use of opiates or barbiturates 4 days prior to trial
• Patients with competing intracerebral pathology (e.g. history of intracerebral hemorrhage, multiple sclerosis)
• NYHA Class III or IV congestive heart failure
• History of myocardial infarction
• History of coronary bypass surgery or coronary stenting
• Pregnancy or breastfeeding
• Contraindication to undergoing brain MRI per standard clinical practice guidelines
• Vulnerable populations, including incarcerated inmates, dementia, and inability to provide consent