Observational Study of Characteristics, Treatment and Outcomes With Severe Asthma in the United States (CHRONICLE)

Inclusion Criteria:

1. Individuals with a diagnosis of severe asthma for at least 12 months prior to enrollment and confirmed by the Investigator not to be due to alternative diagnoses.

2. Currently receiving care from specialist physicians (eg, pulmonologists and or allergists) at the Investigator's or sub-investigator's site.

3. 18 years of age and older. 4. Meeting at least one of the following three criteria (a, b, or c):

a. Uncontrolled asthma while receiving high-dose ICS with additional controllers.

i. Uncontrolled is defined by meeting at least one of the following (as outlined by ATS/ERS [American Thoracic Society/European Respiratory Society] guidelines):

1. Poor symptom control: Asthma Control Questionnaire consistently ≥1.5, ACT <20 (or "not well controlled" by NAEPP [National Asthma Education and Prevention Program]/Global Initiative for Asthma guidelines).

2. Frequent severe exacerbations: two or more bursts of systemic corticosteroids (≥3 days each) in the previous 12 months.

3. Serious exacerbations: at least one hospitalization, intensive care unit stay or mechanical ventilation in the previous 12 months.

4. Airflow limitation: after appropriate bronchodilator withhold FEV1 <80% predicted (in the face of reduced FEV1/FVC defined as less than the lower limit of normal).

ii. For the purposes of this study, high-dose ICS will be defined as

1. ICS at a cumulative dose of >500 μg fluticasone propionate equivalents daily as defined in Appendix A, or 2. Highest labeled dose of a combination of ICS/LABA. b. Current use of a Food and Drug Administration (FDA)-approved monoclonal antibody agent for treatment of severe asthma (use is not primarily for an alternative condition).

c. Use of systemic corticosteroids or other systemic immunosuppressants (any dose level) for approximately 50% or more of the prior 12 months for treatment of severe asthma (use is not primarily for an alternative condition).

Exclusion Criteria

1. Not willing and able to sign written informed consent. Consent can be obtained from having a responsible, legally authorized representative acting on patient's behalf.

2. Not fluent in English or Spanish.

3. Inability to complete study follow-up or web-based PROs. If the patient does not have email or web access, minimal assistance from others to access the web-based PRO is permitted (ie receiving the email and/or assisting patient in navigating to the web page); PROs must be completed by the patient.

4. Received an investigational therapy for asthma, allergy, atopic disease, or eosinophilic disease as part of a clinical trial during the 6 months prior to enrollment.

5. Once enrolled in the CHRONICLE Study, patients can enroll in trials of investigational therapies (as well as other non-interventional studies) as long as they continue to complete study follow-up. If a patient enrolls in a trial of an investigational therapy, the identity (National Clinical Trial [NCT] number) of the study and dates of the first and last investigational therapy administrations will be collected. If a patient receives blinded therapy in a trial, the Investigator will request the identity of that therapy at trial conclusion so that treatment information collected for the current study may be updated accordingly.