Duration of Benefit for OnabotulinumtoxinA in Treatment of Chronic Migraine

Recognizing a commitment to evidence-based science as the pathway to optimize clinical outcomes for patients with chronic migraine (CM) we believe this investigator initiated study (IIS) will: 1. Help clinicians recognize the importance of scheduling patients with CM at intervals not exceeding 12 weeks. 2. Provide biopsy evidence supporting sensory mechanisms involved in the mechanism of action (MOA) of onabotulinumtoxinA (BTX). This does not exclude potential valuable contributions of denervation of motor neurons, but may support a more balanced and understandable mechanism for BTX in treating CM. 3. Provide clinicians important educational information for patients to better manage expectations of using BTX in managing CM and answering critical questions such as: 1. How long does it take for BTX to begin providing a clinical benefit? 2. What is the expected duration of this benefit? * Failure to understand unmet expectations either real or otherwise results in defining BTX treatment as a failure by patients and/or clinicians. 4. Provide validation for patients' reports of shorter duration of action of BTX so patients will not be misinterpreted as non-responders to BTX prematurely. 5. Ascertain if subjects initially reporting short duration of BTX response continue to experience this similar pattern of effect with repeated injection cycles. 6. Provide the first detailed longitudinal assessment of BTX response. 7. Correlate the onset and duration of benefit for subjects receiving BTX. 8. Observe factors predictive of duration of BTX response. This study proposes to accomplish these goals through an exploratory comparison of the clinical efficacy and natural history of BTX measured at weekly time intervals. Subjects reporting short (\<10 weeks) duration of benefit and subjects reporting long (\>10 weeks) duration of clinical benefit will provide the primary comparison. Histological examinations (in a subset of subjects) of neuronal changes associated with regeneration of terminal neuronal endplates will be used to support these clinical observations. This study will follow subjects through 3 injection cycles or 36 weeks. Biopsies will be performed on consenting subjects prior to their first and second injection cycles. Group Assignment At Visit 3, subjects will be assigned to one of three groups (Groups A, B, C) based on their answers to the following questions: 1. Since your last BTX treatment, do you think there has been improvement in your chronic migraine? If the answer to Q1 is yes, subject will answer Q2 and Q3. If the answer is no, subject is assigned to Group C and no further answers are required: 2. How many days did it take for you to first notice benefit from BTX injections? 3. How long did you feel you received benefit from BTX (number of weeks)? Subjects will be assigned into 3 groups: 1. Group A are subjects reporting 10 or less weeks of benefit from BTX; 2. Group B are subjects reporting \>10 weeks of benefit from BTX; 3. Group C are subjects reporting no or minimal (\< 30%) benefit from BTX. Consistency of subjects' perception of BTX benefit at 12 weeks will be compared to responses at 24 and 36 weeks, though Group assignment will remain as defined at 12 weeks. This exploratory study will be conducted at the Headache Care Center in Springfield, MO. Thirty-six subjects, 18 years and older with a history of chronic migraine will be enrolled. The study will consist of 5 visits for all subjects. At Visit 1 (day 1 of baseline) the following study procedures will be performed: * Informed Consent obtained * Migraine, medical and medication history obtained * Physical and neurological exam performed * Urine pregnancy test performed if applicable * Vital signs collected At Visit 2 (day 29 +/- 3 days) the following study procedures will be performed: * Update medical and medication history * Urine pregnancy test performed if applicable * Vital signs collected * Review baseline diary * Complete Migraine Disability Assessment Scale (MIDAS) * Complete Social Readjustment Rating Scale (SRRS) * Complete Beck Depression Inventory II (BDI-II) * Complete State-Trait Anxiety Inventory (STAI) * Complete Sleep Quality Questionnaire * Punch biopsy for neuronal regrowth (subset of subjects) * onabotulinumtoxinA injections At Visit 3 (day 113 +/- 3 days) the following study procedures will be performed: * Update medical and medication history * Urine pregnancy test performed if applicable * Vital signs collected * Complete Subject Global Impression of Change (SGIC) * Complete Physician Global Impression of Change (PGIC) * Complete Migraine Disability Assessment Scale (MIDAS) * Complete Social Readjustment Rating Scale (SRRS) * Complete Beck Depression Inventory II (BDI-II) * Complete State-Trait Anxiety Inventory (STAI) * Complete Sleep Quality Questionnaire * Complete duration of response to onabotulinumtoxinA questions * Punch biopsy for neuronal regrowth (subset of subjects) * onabotulinumtoxinA injections At Visit 4 (day 197 +/- 3 days) the following study procedures will be performed: * Update medical and medication history * Urine pregnancy test performed if applicable * Vital signs collected * Complete Subject Global Impression of Change (SGIC) * Complete Physician Global Impression of Change (PGIC) * Complete Migraine Disability Assessment Scale (MIDAS) * Complete Social Readjustment Rating Scale (SRRS) * Complete Beck Depression Inventory II (BDI-II) * Complete State-Trait Anxiety Inventory (STAI) * Complete Sleep Quality Questionnaire * Complete duration of response to onabotulinumtoxinA questions * onabotulinumtoxinA injections At Visit 5 (day 281 +/- 3 days) the following study procedures will be performed: * Update medical and medication history * Urine pregnancy test performed if applicable * Vital signs collected * Complete Subject Global Impression of Change (SGIC) * Complete Physician Global Impression of Change (PGIC) * Complete Migraine Disability Assessment Scale (MIDAS) * Complete Social Readjustment Rating Scale (SRRS) * Complete Beck Depression Inventory II (BDI-II) * Complete State-Trait Anxiety Inventory (STAI) * Complete Sleep Quality Questionnaire * Complete duration of response to onabotulinumtoxinA questions