The goal of this clinical trial is to compare the efficacy and safety of QL2302 and Tezspire® in patients with uncontrolled severe asthma. The main questions it aims to answer are:

• if the efficacy of QL2302 and Tezspire® are similar
• if the safety of QL2302 and Tezspire® are similar

Participants will be randomised to QL2302 or Tezspire® group and asked to receive one injection of QL2302 or Tezspire® subcutaneously every four weeks till Week 48, which means participants will receive a total of 13 injections. And be observed for another 12 weeks after the end of treatment.

Inclusion Criteria:

1. 18-80 year of age
2. Body weight ≥40 kg
3. Diagnosed with asthma ≥12 months
4. Received a total daily dose of medium/high dose of ICS for more than 3 months steadily
5. 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.
6. Morning pre-BD FEV1 <80% but ≥35% predicted normal
7. Evidence of asthma as documented by reversibility test or change of PEF.
8. Documented history of at least 1 asthma exacerbation events within 12 months.
9. ACQ-5 score ≥1.5 at screening and on day of randomization

Exclusion Criteria:

1. Pulmonary disease other than asthma.
2. History of cancer within 5 years except those cured.
3. History of a clinically significant infection within 4 weeks.
4. Current smokers or participants with smoking history ≥10 pack-yrs.
5. History of chronic alcohol or drug abuse within 12 months.
6. Positive Hepatitis B, C or HIV infection.
7. Pregnant or breastfeeding.
8. History of anaphylaxis following any biologic therapy.
9. Participant received tezepelumab or other TSLP antibody priorly.
10. Participant received bronchial thermoplasty within 12 months.