This is an open-label, single arm study designed to evaluate the safety of tezepelumab administered subcutaneously every 4 weeks in Japanese adult and adolescent subjects with inadequately controlled severe asthma.

This is open-label, single arm study designed to evaluate the safety of tezepelumab in adults and adolescents with severe, uncontrolled asthma on medium to high-dose ICS and at least one additional asthma controller medication with or without OCS. Approximately 66 subjects will be dosed in Japan. Subjects will receive tezepelumab administered via subcutaneous injection at the study site, over a 52-week treatment period. The study also includes a post-treatment follow-up period of 12 weeks.

Inclusion Criteria:

Age. 12-80 Documented physician-diagnosed asthma for at least 12 months Subjects who have received a physician-prescribed asthma controller medication with medium or high dose ICS for at least 12 months.

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.

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.

Documented history of at least 1 asthma exacerbation events within 12 months. ACQ-6 score ≥1.5 at screening or on day of registration.

Exclusion Criteria:

Pulmonary disease other than asthma. History of cancer. History of a clinically significant infection. Current smokers or subjects with smoking history ≥10 pack-yrs. History of chronic alcohol or drug abuse within 12 months. Hepatitis B, C or HIV. Pregnant or breastfeeding. History of anaphylaxis following any biologic therapy. Subject randomized in the current study or previous tezepelumab studies

Qualified researchers can request access to anonymized individual patient-level data from AstraZeneca group of companies sponsored clinical trials via the request portal. All request will be evaluated as per the AZ disclosure commitment:

https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure. Yes, indicates that AZ are accepting requests for IPD, but this does not mean all requests will be shared.

AstraZeneca will meet or exceed data availability as per the commitments made to the EFPIA Pharma Data Sharing Principles. For details of our timelines, please rerefer to our disclosure commitment at https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure.

When a request has been approved AstraZeneca will provide access to the deidentified individual patient-level data in an approved sponsored tool . Signed Data Sharing Agreement (non-negotiable contract for data accessors) must be in place before accessing requested information. Additionally, all users will need to accept the terms and conditions of the SAS MSE to gain access. For additional details, please review the Disclosure Statements at https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure.

From first dose of study drug until last study visit at Week 64