Dose-ranging Study of Vilanterol (VI) Inhalation Powder in Children

Change From Baseline in Evening Clinic Visit Trough (Pre-bronchodilator and Pre-dose) Forced Expiratory Volume in One Second (FEV1) at the End of the 4-week Treatment Period in Children Who Could Perform the Maneuver

Pulmonary function was measured by FEV1, defined as the maximal amount of air that can be forcefully exhaled in one second. Trough FEV1 is defined as a pre-dose FEV1 measurement taken at a clinic visit while still on treatment. Change from Baseline in trough FEV1 at the end of the 4-week Treatment Period was defined using the pre-dose FEV1 measurement taken at the Week 4 clinic visit. Change from Baseline was calculated as the Week 4 trough FEV1 value minus the Baseline value. The Baseline FEV1 value is defined as the value at Visit 3 (randomization). The analysis was performed using an ANCOVA model with covariates of Baseline trough FEV1, region, sex, age, and treatment. The last observation carried forward (LOCF) method was used to impute missing data, in which the last non-missing post-Baseline on-treatment measurement at scheduled clinic visits was used to impute the missing measurements.

Time frame: Baseline; Week 4

Change From Baseline in the Percentage of Rescue-free 24-hour Periods During the 4-week Treatment Period

The number of inhalations of rescue albuterol/salbutamol inhalation aerosol (medication used to relieve symptoms immediately) used during the day and night) was recorded by the participants in a daily diary. A 24-hour period in which a participant's responses to both the morning and evening assessments indicated no use of rescue medication was considered as rescue free. Participants who were rescue free for 24-hour periods during the 4-week Treatment Period were assessed. The Baseline value was derived from the last 7 days of the daily diary prior to the randomization of the participant. Change from Baseline is calculated as the average value during the 4-week Treatment Period minus the value at Baseline. The Baseline value is defined as the value at Visit 3 (randomization). Analysis was performed using ANCOVA with covariates of Baseline, region, sex, age, and treatment.

Time frame: Baseline; Week 1 up to Week 4

Change From Baseline in Daily Morning (AM) PEF Averaged Over the 4-week Treatment Period

PEF is defined as the maximum airflow during a forced expiration beginning with the lungs fully inflated. PEF was measured by the participants using a hand-held electronic peak flow meter each morning prior to the dose of study medication and any rescue albuterol/salbutamol inhalation aerosol use. Change from Baseline was calculated as the value of the averaged daily AM PEF over the 4-week Treatment Period (at Week 4) minus the Baseline value. The Baseline value is defined as the value at Visit 3 (randomization). The analysis was performed using an ANCOVA model with covariates of Baseline, region, sex, age, and treatment group.

Time frame: Baseline; Week 1 up to Week 4

Change From Baseline in Evening (PM) PEF Over the Last 7 Days of the Treatment Period (Week 4)

PEF is defined as the maximum airflow during a forced expiration beginning with the lungs fully inflated. PEF was measured by the participants using a hand-held electronic peak flow meter each evening prior to the dose of study medication and any rescue albuterol/salbutamol inhalation aerosol use. Change from Baseline is calculated as the value over the last 7 days of the Treatment Period minus the Baseline value. The Baseline value is defined as the value at Visit 3 (randomization). The analysis was performed using an ANCOVA model with covariates of Baseline, region, sex, age, and treatment group. The LOCF method was used to impute missing data, in which the last non-missing post-Baseline on-treatment measurement at scheduled clinic visits was used to impute the missing measurements.

Time frame: Baseline; Week 4

Change From Baseline in AM PEF Over the Last 7 Days of the Treatment Period (Week 4)

PEF is defined as the maximum airflow during a forced expiration beginning with the lungs fully inflated. PEF was measured by the participants using a hand-held electronic peak flow meter each morning prior to the dose of study medication and any rescue albuterol/salbutamol inhalation aerosol use. Change from Baseline is calculated as the value of the averaged daily AM PEF over the 4-week Treatment Period (at Week 4) minus the Baseline value. The Baseline value is defined as the value at Visit 3 (randomization). The analysis was performed using an ANCOVA model with covariates of Baseline, region, sex, age, and treatment group.

Time frame: Baseline; Week 4

Change From Baseline in the Percentage of Symptom-free 24-hour Periods During the 4-week Treatment Period

Asthma symptoms were recorded in a daily eDairy by the participants every day in the morning and evening before taking any rescue or study medication and before the PEF measurement. A 24-hour (hr) period in which a participant's responses to both the morning and evening assessments indicated no symptoms was considered to be symptom free. The Baseline symptom-free value is defined as the value at Visit 3 (randomization). Change from Baseline was calculated as the averaged value during the 4-week Treatment Period minus the Baseline value. The analysis was performed using an ANCOVA model with covariates of Baseline, region, sex, age, and treatment group.

Time frame: Baseline; Week 1 up to Week 4