A Study to Investigate the Efficacy and Safety of Tezepelumab Compared With Placebo in Children 5 to < 12 Years Old With Severe Asthma

Inclusion Criteria:

1. Written informed consent from (ICF) at least one parent/caregiver (as per localguidelines) and accompanying informed assent from the participant (where theparticipant is able to provide assent) prior to admission to the study.

2. Participants must be 5 to < 12 years of age, at the time of signing the assent form (as applicable per local guidelines) and their caregivers signing the ICF and atVisit 3.

3. Documented physician diagnosis of severe asthma confirmed and evaluated for at least 6 months prior to Visit 1.

4. Documented physician-prescribed treatment with a total daily dose of either mediumor high dose, for at least 3 months with stable dose ≥ 1 month prior to Visit 1.

5. Documented treatment with at least one additional maintenance asthma controllermedication is required according to local guidelines and standard of care; (long-acting beta agonist, leukotriene receptor antagonist, long-acting muscarinicantagonist) for at least 3 months with stable dose ≥ 1 month prior to Visit 1.

6. Supportive evidence of asthma as documented by one of the following:

7. Post-BD (albuterol/salbutamol) responsiveness of FEV1 ≥ 10% during Screening (15 to 30 min after administration of 4 puffs of albuterol/salbutamol with amaximum of 12 puffs of reliever medication only if tolerated by theparticipant) at either Visit 1 or Visit 2.If (a) is not achieved at Visit 1 or Visit 2, historical documentation by anyof the below prior to Visit 1:

8. Post-BD responsiveness of FEV1 ≥ 10%.

9. Positive methacholine challenge defined as provocative concentration (PC20) of ≤ 16 mg/mL.

10. PEF average daily diurnal variability > 13% over a 2-week period.

11. Variability of FEV1 ≥ 12% between any two clinical visits.

12. Positive exercise challenge test (defined as a fall in FEV1 of > 12%).

13. FeNO ≥ 20 ppb despite confirmed ICS maintenance therapy.

14. History of at least 2 severe asthma exacerbation events OR 1 severe asthmaexacerbation event resulting in hospitalisation within 12 months prior to Visit 1.

15. Pre-BD FEV1 >50% and ≤ 95%PN OR FEV1/forced vital capacity (FVC) ratio ≤ 0.85 ateither Visit 1 or Visit 2.

16. Evidence of uncontrolled asthma, with at least 1 of the below criteria:

17. ACQ-IA score ≥ 1.5 at least once during Screening/Run-in, including Visit 3 (prior to Randomisation) for participants ≥ 6 years old at Screening.

18. Use of reliever medication, other than as a preventive for exercise inducedbronchospasm, on 3 or more days per week for at least 1 week during theScreening/Run-in period.

19. Sleep awakening due to asthma symptoms requiring use of reliever medication atleast once during the Screening/Run-in period.

20. Asthma symptoms 3 or more days per week in at least 1 week during theScreening/Run-in period.

21. Body weight ≥ 16 kg at Visit 1 (Screening) and Visit 3 (Randomisation).

Exclusion Criteria:

1. History of vocal cord dysfunction, cystic fibrosis, primary ciliary dyskinesia, orchronic rhinosinusitis with nasal polyposis.

2. History of any clinically significant disease or disorder other than asthma which,in the opinion of the investigator, may either put the participant at risk becauseof participation in the study, or influence the results or the participant's abilityto participate in the study.

3. History of a clinically significant deterioration in asthma or asthma exacerbationincluding those requiring use of systemic corticosteroids or increase in themaintenance dose of oral corticosteroids within 30 days prior to Visit 1.

4. Change in ICS dose within 1 month prior to Visit 1.

5. History of a life-threatening asthma exacerbation resulting in a hypoxic seizure orrequiring intubation.