Tezepelumab Home Use Study

Inclusion Criteria: * Male or female, age 12 to 80 years. * Documented physician-diagnosed asthma for at least 12 months. * Evidence of asthma as documented by post BD (albuterol/salbutamol) reversibility of FEV1 ≥ 12% AND ≥200 mL (15-60 min after administration of 4 puffs of albuterol/salbutamol), documented either: in the previous 12 months prior to V1, OR demonstrated at V1, V1A, or at V2. * Documented history of current treatment with medium- or high-dose ICS for at least 6 months and at least one additional asthma controller medication according to standard practice of care. ICS dose must be greater than or equal to 500 μg/day fluticasone propionate dry powder formulation or equivalent daily. * Morning pre-BD FEV1 of \>50% predicted normal at Visit 1, Visit 1A, or Visit 2. Exclusion Criteria: * Clinically important pulmonary or systemic diseases other than asthma. * History of cancer except basal cell carcinoma, squamous cell carcinoma, or in situ carcinoma of the cervix within 12 months prior to Visit 1. * Acute upper or lower respiratory infection requiring antibiotics or antiviral medications finalized \<2 weeks before Visit 1 or during screening/run-in period. * A helminth parasitic infection diagnosed within 6 months that is untreated or is unresponsive to the standard of care. * Smoking history of ≥10 pack years, (includes vaping and e-cigarettes) * History of chronic alcohol or drug abuse. * Tuberculosis requiring treatment within 12 months prior to V1. * History of HIV, Hepatitis B or Hepatitis C. * 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. * Bronchial thermoplasty in 24 months prior to V1. * Anaphylaxis or documented immune complex disease (Type III hypersensitivity reactions) to any biologic therapy. * Evidence of active liver disease (e.g. jaundice, AST, ALT or ALP \>2 times upper limit of normal), ongoing liver disease or inexplicably elevated liver chemistry values. * Pregnant, breastfeeding or lactating women. * Non-leukocyte depleted whole blood transfusion in 120 days prior to visit 1.