Tezepelumab Efficacy and Safety in Reducing Oral Corticosteroid Use in Adults With Oral Corticosteroid Dependent Asthma

Main inclusion criteria: 1. Participant must be 18 to 80 years of age. 2. Documented physician-diagnosed asthma for at least 12 months prior to Visit 1. 3. Participants must have received a physician-prescribed medium- or high-dose ICS for at least 12 months prior to Visit 1. 4. Participants must have received physician prescribed LABA and high dose ICS for at least 3 months prior to Visit 1. 5. Additional maintenance asthma controller medications are allowed. The use of these medications must be documented for at least 3 months prior to Visit 1. 6. Participants must have received OCS for the treatment of asthma for at least 6 months prior to Visit 1 and on a stable dose of between ≥7.5 to ≤ 30 mg (prednisone or prednisolone) daily or daily equivalent for at least 1 month prior to Visit 1. 7. Morning pre- bronchodilator (BD) FEV1 must be \< 80% predicted normal at Visit 1 or Visit 2. 8. Evidence of asthma as documented by either: a)Post-BD responsiveness test result: FEV1 ≥12% and ≥200 mL documented either in the previous 60 months prior to or at Visit 1 or at Visit 2 or at Visit 3; OR b)Airway hyperresponsiveness (methacholine: provocative concentration that causes a positive reaction \[PC20\] of \<8 mg/mL) documented in the 60 months prior to Visit 1. 9. Blood eosinophils at Visit 1 ≥150 cells/μL or documented EOS ≥300 cells/μL within 12 months prior to Visit 1. 10. Participants must have a history of at least 1 asthma exacerbation event within 24 months prior to Visit 1. 11. Participants must have received the optimised OCS dose for at least 2 weeks prior to randomisation. Other inclusion criteria per protocol apply. Main exclusion criteria 1. Any clinically important pulmonary disease other than asthma. 2. Any disorder that is not stable in the opinion of the Investigator and could: a. Affect the safety of the participant throughout the study; b. Influence the findings of the study or the interpretation; c. Impede the participant's ability to complete the entire duration of study. 3. History of cancer: a. Participants who have had basal cell carcinoma, localised squamous cell carcinoma of the skin or in situ carcinoma of the cervix are eligible to participate in the study provided that curative therapy was completed at least 12 months prior to Visit 1; b. Participants who have had other malignancies are eligible provided that curative therapy was completed at least 5 years prior to Visit 1. 4. Asthma exacerbation, requiring use of systemic corticosteroids or increase in the maintenance dose of OCS finalized within 30 days prior to Visit 1. 5. Clinically significant infection requiring treatment with systemic antibiotics or antiviral medications finalized \< 2 weeks before Visit 1 or during the run-in period. 6. Participants with evidence of active COVID-19 infection during run-in period and optimisation. 7. A helminth infection diagnosed within 6 months prior to Visit 1 that has not been treated with, or has failed to respond to, standard of care therapy. 8. A participant who is on SABA maintenance treatment within 30 days prior to Visit 1. 9. Current smokers or participants with smoking history ≥ 10 pack-years and participants using vaping products, including electronic cigarettes. Former smokers with a smoking history of \<10 pack years and users of vaping or e-cigarette products must have stopped for at least 6 months prior to Visit 1 to be eligible. 10. Receipt of any marketed or investigational biologic agent within 4 months or 5 half-lives (whichever is longer) prior to Visit 1 or receipt of any investigational non-biologic agent within 30 days or 5 half-lives (whichever is longer) prior to Visit 1. 11. COVID-19 vaccination within 28 days prior to randomisation. 12. Tuberculosis requiring treatment within the 12 months prior to Visit 1. 13. During the optimisation period, asthma control reached at an OCS dose of \<7.5 mg or \>30 mg and/or 3 consecutive dose reductions after which asthma control was still obtained. Other exclusion criteria per protocol apply.