Study to Evaluate the Safety and Efficacy of CAT-354

Time to first asthma control was defined as the number of days from Study Day 1 to the post-baseline ACQ score measurement time point when greater than or equal to (>=) 0.5 reduction from baseline in mean ACQ score was first observed. Time to first asthma control was analyzed from Day 1 through Day 92 and up to entire study duration through Day 169. The ACQ score is a participant-reported questionnaire to assess the asthma control with 6 items assessing night-time waking, symptoms on waking, activity limitation, shortness of breath, wheeze, and rescue short-acting beta agonist use. Each item was rated on a 7-point Likert scale ranging from 0 (no impairment) to 6 (maximum impairment). Overall ACQ score is the mean of the 6 item scores with a score range of 0 (well controlled) to 6 (extremely poor controlled).

Forced Expiratory Volume in 1 Second (FEV1) is the maximal volume of air exhaled in the first second of a forced expiration from a position of full inspiration. Spirometry was performed with the participant in the sitting/standing (kept consistent at each visit) position at study sites by the investigator or qualified designee according to American Thoracic Society (ATS)/European Respiratory Society (ERS) guidelines. Multiple forced expiratory efforts (at least 3 but no more than 8) were performed for each office spirometry session and the 2 best efforts that met ATS/ERS acceptability and reproducibility criteria were recorded. The best efforts were based on the highest FEV1. The maximum FEV1 of the 2 best efforts was used for the analysis. Data collected on Day 1 prior to dosing was considered as baseline.

The PEF is a participant's maximum speed of expiration, as measured with a peak flow meter. Home peak flow testing for PEF was performed every morning while sitting or standing prior to using any medication (if needed) for asthma. Mean of the data was collected over 1 week prior to dosing on Day 1 was considered as baseline. Mean PEF values for each week were used to calculate the change from baseline values starting from Day 2 to 169.

Number of Puffs of Rescue Beta-2 Agonist Per Week Rescue beta-2 agonist use (total number of puffs for the preceding week) was collected daily in the morning by the participants in the daily diary provided to them. Average values for each week were reported starting from Day -7 to Day 169.

Asthma Quality of Life Questionnaire (Standardized Version) (AQLQ[S]): a 32-item questionnaire that measures the functional impairments experienced by adult participants including 4 domains (Symptoms, Activity Limitations, Emotional Function, and Environmental Stimuli). Participants were asked to recall their experiences during the previous 2 weeks and to score each of the 32 questions on a 7-point scale ranging from 7 (no impairment) to 1 (severe impairment). The overall score was calculated as the mean response to all questions. The 4 domain scores were the means of the responses to the questions in each of the domains. Overall AQLQ score and 4 domain scores ranged from 7 (no impairment) to 1 (severe impairment).

Asthma Quality of Life Questionnaire (Standardized Version) (AQLQ[S]): a 32-item questionnaire that measures the functional impairments experienced by adult participants including 4 domains (Symptoms, Activity Limitations, Emotional Function, and Environmental Stimuli). Participants were asked to recall their experiences during the previous 2 weeks and to score each of the 32 questions on a 7-point scale ranging from 7 (no impairment) to 1 (severe impairment). The overall score was calculated as the mean response to all questions. The 4 domain scores were the means of the responses to the questions in each of the domains. Overall AQLQ score and 4 domain scores ranged from 7 (no impairment) to 1 (severe impairment). Data collected on Day 1 prior to dosing was considered as baseline

Patient Global Impression of Change (PGIC): participant rated instrument to measure participant's change in overall status compared to baseline on a 7-point scale; range from 1 (very much worse) to 7 (very much better).

Percentage of participants with mean Asthma Control Questionnaire (ACQ) score less than or equal to (<=) 0.75 or mean ACQ score greater than (>) 0.75 and less than (<) 1.5 were analyzed. The ACQ is a participant-reported questionnaire to assess the asthma control with 6 items assessing night-time waking, symptoms on waking, activity limitation, shortness of breath, wheeze, and rescue short-acting beta agonist use. Each item was rated on a 7-point Likert scale ranging from 0 (no impairment) to 6 (maximum impairment). Overall ACQ score is the mean of the 6 item scores with a score range of 0 (well controlled) to 6 (extremely poor controlled). Mean ACQ scores of less than or equal to (<=) 0.75 indicated well-controlled asthma, mean ACQ scores greater than (>) 0.75 but less than (<) 1.5 indicated partly controlled asthma.

An adverse event (AE) was any untoward medical occurrence attributed to study drug in a participant who received study drug. A serious adverse event (SAE) was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly. Treatment-emergent are events between first dose of study drug and Day 169 that were absent before treatment or that worsened relative to pretreatment state.

Asthma exacerbation was defined as either a progressive increase of asthma symptoms (cough, wheeze, chest tightness, and/or shortness of breath) or a reduction of >= 20 percent (%) in PEF or FEV1 from baseline that did not resolve after the initiation of rescue medications and resulted in an administration of systemic corticosteroids by the investigator or health care provider. Asthma exacerbation severity was classified as: 1) Moderate-worsening symptoms that required systemic corticosteroids. 2) Severe-worsening symptoms that required systemic corticosteroids and hospital admission.

Asthma exacerbation was defined as either a progressive increase of asthma symptoms (cough, wheeze, chest tightness, and/or shortness of breath) or a reduction of >=20% in PEF or FEV1 from baseline that did not resolve after the initiation of rescue medications and resulted in an administration of systemic corticosteroids by the investigator or health care provider. Asthma exacerbation rate, calculated as total asthma exacerbations per person per annum, was assessed based on asthma exacerbation data up to Day 92 and 169 (Rate = mean asthma exacerbations for all participants/X days*365 days, where X = 92 or 169).

Time to first moderate or severe asthma exacerbation was defined as time to first observed progressive increase of asthma symptoms (cough, wheeze, chest tightness, and/or shortness of breath) or a reduction of >=20% in PEF or FEV1 from baseline that did not resolve after the initiation of rescue medications and resulted in an administration of systemic corticosteroids by the investigator or health care provider.