The number of participants with at least 50% reduction in migraine frequency (average weekly number of migraine episodes) through the end of the 91-day treatment period compared with Baseline (the 25- to 35-day baseline qualification period). Participants recorded the incidence, timing and intensity of migraines in a migraine diary during the prequalification period and throughout the 91-day treatment period.

Intent-to-treat population

The percentage of participants with at least 50% reduction in migraine frequency (average weekly number of migraine episodes) compared to Baseline at each month of the treatment period.

Intent-to-treat population with available data. N indicates the number of participants with available data at each time point.

Migraine severity was recorded by participants in the Baseline qualification diary and study migraine diary during the treatment period. Participants could report a severity of none (score = 0), mild (1), moderate (2), or severe (3). In general, if a headache was mild, daily activities could be resumed and little to no medication was taken. Moderate headaches required medication and effected daily activities. Severe headaches were debilitating and required medication.

Average migraine severity is defined as the sum of the severity ratings divided by the total number of migraine episodes reported during the observation period (for example, Baseline, First Month, Second Month, Third Month, and 91-Day Treatment Period). A negative change from Baseline score indicates improvement in severity.

Intent-to-treat population with available data. N indicates the number of participants with available data at each time period.

Participants recorded use of rescue medications for migraines in the migraine diary during the course of study treatment.

Intent-to-treat population with available data. N indicates the number of participants with available data at each time period.

The migraine disability assessment (MIDAS) test is used to determine how severely migraines affect a patient's life. Participants were asked five questions about how often their headaches limited their ability to go to work or school, to do household work or to do family or leisure activities in the past 3 months.

The MIDAS score equals the sum of the days answered for each question and ranges from 0 (no disability) to approximately 270 (severe disability; the upper bound is dependent on the number of days a participant would plan to work or participate in other activities).

The MIDAS score is classified into four grades of severity:

• 0 to 5: MIDAS Grade I, Little or no disability
• 6 to 10: MIDAS Grade II, Mild disability
• 11 to 20: MIDAS Grade III, Moderate disability
• 21+: MIDAS Grade IV, Severe disability

Intent-to-treat population with available data.

The Headache Impact Test (HIT) is a tool used to measure the impact headaches have on patients' ability to function on the job, at school, at home and in social situations.

HIT-6 consists of 6 questions each scored on a scale from Never (6 points) to Always (13 points). The total score ranges from 36 to 78 with higher scores indicating greater impact on life.

There was an error in administration of the HIT-6 in this study. Question 6 was not administered, and question 3 from the MIDAS was included instead. Therefore, the total score of the HIT-6 could not be calculated.

Analysis was not performed due to an error in the administration of the test.

An AE is any untoward medical occurrence in a clinical investigation participant and which does not necessarily have to have a causal relationship with this treatment or clinical study.

The following definitions were used to assess AE severity: Mild: Awareness of signs or symptoms, but they are easily tolerated; Moderate: Enough discomfort to cause interference with usual activity; Severe: Incapacitating, with inability to perform usual activity.

Relationship to study drug was assessed as either: None: Causal relationship can be ruled out; Possibly: Causal relationship at least reasonably possible, i.e. relationship cannot be ruled out; Definitely: Causal relationship is certain.

A serious adverse event (SAE) is one that met any one of the following criteria:

• Fatal or life threatening
• Requires or prolongs in patient hospitalization
• Results in persistent or significant disability/incapacity
• Congenital anomaly / birth defect
• Important medical event.

Safety population, consisting of all participants who received at least one dose of study drug.

Bleeding and spotting were recorded by participants in the migraine diary during the 91-day treatment period.

Safety population with available data