A Study to Assess the Efficacy and Safety of MSTT1041A in Participants With Uncontrolled Severe Asthma

Asthma exacerbation was defined as new or increased asthma symptoms (wheezing, coughing, dyspnea, chest tightness, and/or nighttime awakenings due to these symptoms) that result in one or both of the following: Hospitalization or emergency department visit with administration of systemic corticosteroid treatment; Treatment with systemic corticosteroids for at least 3 days, or a long-acting depot corticosteroid preparation with a therapeutic effectiveness of at least 3 days.

Adjusted rates for the overall mITT population (all participants that received at least one dose of study drug) were estimated using Poisson regression and adjusted for blood eosinophil level at the first visit, the number of asthma exacerbations requiring systemic corticosteroids in the 12 months prior to study entry, the total daily ICS dose at the first visit, and geographic region, with patient time at risk used as an offset term.

FEV1 measures how much air a person can exhale during the first second of a forced breath.

Adjusted means are reported.

Asthma exacerbation was defined as new or increased asthma symptoms (wheezing, coughing, dyspnea, chest tightness, and/or nighttime awakenings due to these symptoms) that result in one or both of the following: Hospitalization or emergency department visit with administration of systemic corticosteroid treatment; Treatment with systemic corticosteroids for at least 3 days, or a long-acting depot corticosteroid preparation with a therapeutic effectiveness of at least 3 days.

The AQLQ measures the functional problems (physical, emotional, social, and occupational) most troublesome to adults (17-70 years) with asthma. There are 32 questions in 4 domains - symptoms, activity limitation, emotional function, and environmental stimuli - scored on a 7 point scale, with 7= no impairment and 1= severely impaired. For this study, improvement achievement was defined as an increase of at least 0.5 points from baseline to week 54.

Adjusted rates are reported.

Adjusted mean values are all equal to zero.

The adjusted mean proportion of weeks without a nighttime awakening from baseline through week 54 are reported. The proportion of weeks is expressed as a percentage.

The ADSD is a 6-item daily measure of asthma symptom severity that assesses three core categories of asthma symptoms: breathing symptoms, chest symptoms, and cough. Symptoms are rated at their worst using an 11-point numeric rating scale ranging from 0 (no symptoms) to 10 (the worst symptoms imaginable).

Adjusted means are reported.

An adverse event is any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with the treatment. An adverse event can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding, for example), symptom, or disease temporally associated with the use of a pharmaceutical product, whether or not considered related to the pharmaceutical product. Preexisting conditions which worsen during a study are also considered as adverse events.

The prevalence of ADAs at baseline was defined as the proportion of the evaluable participant population in a study that is ADA positive at baseline.

The incidence of ADAs at post-baseline timepoints was defined as the proportion of the study population found to have developed treatment-emergent ADAs.