Study to Evaluate Tezepelumab in Adults With Severe Uncontrolled Asthma

Inclusion Criteria:

1. Age. 18-80
2. Documented physician-diagnosed asthma for at least 12 months
3. Participants who have received a physician-prescribed asthma controller medication with medium or high dose ICS for at least 6 months.
4. Documented treatment with a total daily dose of either medium or high dose ICS (≥ 500 µg fluticasone propionate dry powder formulation equivalent total daily dose) for at least 3 months.
5. At least one additional maintenance asthma controller medication is required according to standard practice of care and must be documented for at least 3 months.
6. Morning pre-BD FEV1 <80% predicted normal
7. Evidence of asthma as documented by either: Documented historical reversibility of FEV1 ≥12% and ≥200 mL in the previous 12 months OR Post-BD (albuterol/salbutamol) reversibility of FEV1 ≥12% and ≥200 mL during screening.
8. Documented history of at least 2 asthma exacerbation events within 12 months, and at least one of the exacerbations should occur during the treatment of medium-to-high dose ICS.
9. ACQ-6 score ≥1.5 at screening and on day of randomization

Exclusion Criteria:

1. Pulmonary disease other than asthma.
2. History of cancer.
3. History of a clinically significant infection.
4. Current smokers or participants with smoking history ≥10 pack-yrs.
5. History of chronic alcohol or drug abuse within 12 months.
6. Hepatitis B, C or HIV.
7. Pregnant or breastfeeding.
8. History of anaphylaxis following any biologic therapy.
9. participant randomized in the current study or previous tezepelumab studies.