The purpose of this study is to evaluate the Pharmacodynamic, Efficacy and Safety of SHR-1703 in Asthma Patients with Eosinophil Phenotype.

Inclusion Criteria:

1. Aged 18 to 75years (inclusive).
2. Weight ≥40 kg.
3. History of asthma≥ 1 year.
4. Documented treatment with Medium or high daily dose inhaled corticosteroid with additional controller medication within the 3 months prior to randomization.
5. Previously confirmed history of one or more asthma exacerbations within 1 year prior to randomization.
6. Blood eosinophils of ≥150 cells/µL at screening and baseline.
7. Pre-Bronchodilator FEV1% pred≥40% and<80% at screening and baseline.
8. Asthma Control Questionnaire-6 score≥1.5.
9. Use highly effective contraceptive measures.
10. Willing to sign the informed consent form to participate in this study.

Exclusion Criteria:

1. Subjects with Clinically significant pulmonary diseases；
2. Subjects with other diseases that could lead to elevated eosinophils；
3. Subjects with Immunodeficiency；
4. Poorly controlled hypertension;
5. Subjects with severe cerebrovascular disease;
6. Subjects with infection history requiring clinical intervention；
7. Subjects with parasitic infection；
8. Diagnosed Malignant tumor within 5 years prior to randomization;
9. Used non-selective β-blockers within 1 week prior to randomization;
10. Used either 5-lipoxygenase inhibitor or Phosphodiesterase-4 inhibitor within 1 week prior to randomization;
11. Blood donation or massive blood loss, or transfusion of blood products or immunoglobulins within 4 weeks prior to randomization;
12. Live attenuated vaccine inoculated within 4 weeks before randomization;
13. Allergen Immunotherapy within 8 weeks prior to randomization；
14. Used systemic immunosuppressants or immunomodulators, or biologics or Th2 cytokine inhibitors within 12 weeks prior to randomization or within 5 half-lives of the drug;
15. Bronchial thermoplasty within 1 year prior to randomization；
16. Subjects have planned Surgery or other medical procedures that may affect evaluation during the study period;
17. Subjects with significant laboratory abnormality at screening；
18. Subjects have prolonged QTc interval or other electrocardiogram abnormality with significant safety risk at screening;
19. Current smokers or ex-smokers who have given up smoking for <6 months ，or positive smoke test, and/or have a smoking pack history of > 10 pack years;
20. History of drug or substance abuse or alcohol abuse within 1 year prior to screening;
21. Subjects participated another clinical studies and received active drug within 30 days or 5 half-lives prior to screening;
22. Subjects is pregnant, lactating,or planning to become pregnant;
23. Subjects have a known history of hypersensitivity or intolerance to anti-IL-5 mabs or other biological agents;
24. Other conditions unsuitable for participation in the study per investigator judgement.