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

Inclusion Criteria:

- Body mass index (BMI) of 18 to 38 kilogram/square meter (kg/m^2) and weight >= 40 kg
at screening

- Documented physician-diagnosed asthma

- On high dose inhaled corticosteroid (ICS) therapy plus at least one additional allowed
controller medication

- Forced expiratory volume in 1 second (FEV1) of 40% to 80% of predicted

- Evidence of uncontrolled asthma

- Use of contraceptive measures

Exclusion Criteria:

- Diagnosis of mimics of asthma

- Diagnosis of occupational asthma, aspirin-sensitive asthma, asthma chronic obstructive
pulmonary disease overlap syndrome, or bronchiolitis, as determined by the
investigator

- Pregnant or lactating, or intending to become pregnant during the study or within 20
weeks after the last dose of MSTT1041A

- Recent history of smoking

- History or evidence of substance abuse that would pose a risk to participants safety,
interfere with the conduct of the study, have an impact on the study results

- Asthma exacerbation within 4 weeks prior to screening

- Intubation for respiratory failure due to asthma within 12 months prior to screening

- Comorbid conditions that may interfere with evaluation of investigational medicinal
product

- Known sensitivity to any of the active substances or their excipients to be
administered during dosing

- Positive pregnancy test