A study to investigate the efficacy and safety of tezepelumab compared with placebo in children 5 to < 12 years old with severe asthma - HORIZON

Inclusion Criteria

• 1. Written informed consent from (ICF) at least one parent/caregiver (as per local guidelines) and accompanying informed assent from the participant (where the participant 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 at Visit 3.
• 3.Documented physician diagnosis of severe asthma for at least 6 months prior to Visit 1.
• 4.Documented physician-prescribed treatment with a total daily dose of either medium or 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 controller medication is required according to local guidelines and standard of care; (long-acting beta agonist, leukotriene receptor antagonist, long-acting muscarinic antagonist) for at least 3 months with stable dose ≥ 1 month prior to Visit 1.
• 6. Evidence of asthma as documented by one of the following:
• (a) Documented historical BD responsiveness of FEV1 ≥ 10% in the previous 12 months prior to Visit 1 OR
• (b) Documented historical methacholine challenge result of ≤ 16 mg/mL in the previous 12 months prior to Visit 1 OR
• (c) Post-BD (albuterol/salbutamol) responsiveness of FEV1 ≥ 10% during Screening (15 to 30 min after administration of 4 puffs of albuterol/salbutamol) at either Visit 1 or Visit 2.
• 7.History of at least 2 severe asthma exacerbation events OR 1 severe asthma exacerbation event resulting in hospitalisation within 12 months prior to Visit 1.
• 8.Pre-BD FEV-1 >50% and ≤ 95%PN OR FEV1/forced vital capacity (FVC) ratio ≤ 0.8 at either Visit 1 or Visit 2.
• 9. Evidence of uncontrolled asthma, with at least 1 of the below criteria:
• (a) 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
• (b) Use of reliever medication, other than as a preventive for exercise induced bronchospasm, on 3 or more days per week for at least 1 week during the Screening/Run-in period
• (c) Sleep awakening due to asthma symptoms requiring use of reliever medication at least once during the Screening/Run-in period
• (d) Asthma symptoms 3 or more days per week in at least 1 week during the Screening/Run-in period
• 10. Body weight ≥ 16 kg at Visit 1 (Screening) and Visit 3 (Randomisation).