Efficacy and Safety Study of BOTOX® Compared to Topiramate for the Prevention of Chronic Migraine in Adults

Inclusion Criteria:

- History of chronic migraine

- More than 15 headache days in a 28 day period (headaches that last more than 4 hours
and/or require treatment with prescription medication).

Exclusion Criteria:

- Taking opioid-containing products for acute headache treatment more than 8 days during
a 28-day period

- Previous treatment with botulinum toxin of any serotype for any reason

- Previous treatment with topiramate

- On a ketogenic diet (high in fat, low in carbohydrates)

- History of acute myopia or increased intraocular pressure

- Diagnosis of myasthenia gravis, Eaton-Lambert syndrome, amyotrophic lateral sclerosis
or any other significant disease that might interfere with neuromuscular function

- Acupuncture, transcutaneous electrical stimulation (TENS), cranial traction, dental
splints for headache, or injection of anesthetics/steroids in the 4 weeks prior to
screening.