A Study to Evaluate the Efficacy and Safety of SHR-1703 in Subjects With Eosinophilic Granulomatosis With Polyangiitis （EGPA）

Inclusion Criteria:

1. Male or female subjects age 18 years or older;

2. Diagnosed with EGPA for at least 6 months;

3. History of relapsing or refractory EGPA；

4. Stable dose of oral prednisone of ≥7.5 mg/day (but not >50 mg/day) for at least 4weeks prior to randomization;

5. If receiving immunosuppressive therapy (excluding cyclophosphamide), the dosage mustbe stable within 4 weeks prior to randomization and during the study.

Exclusion Criteria:

1. Subjects with other eosinophilic-related diseases;

2. Diagnosed with granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA).

3. Life-threatening EGPA within 3 months prior to randomization;

4. Malignancy history within 5 years prior to randomization;

5. Immunodeficiency;

6. Uncontrolled hypertension；

7. Uncontrolled cerebrovascular and cardiovascular disease;

8. parasitic infection within 6 months prior to randomization;

9. Active infectious disease requiring clinical treatment within 4 weeks prior torandomization;

10. Subjects with a dose of oral prednisone of >50 mg/day within 4 weeks prior torandomization;

11. Oral or intravenous cyclophosphamide therapy within 4 weeks prior to randomization;

12. Intravenous or subcutaneous immunoglobulin within 12 weeks prior to randomization;

13. Biological agents or TH2 cytokine inhibitors used within 12 weeks prior torandomization or within 5 half-lives of the drug;

14. Rituximab used within 6 months prior to randomization；

15. Surgical plans that might affect the evaluation;

16. Significant laboratory abnormalities；

17. Prolonged QTc interval or other electrocardiogram abnormalities with significantsafety risk at screening;

18. History of drug or substance abuse or alcohol abuse within 1 year prior toscreening;

19. Subjects participated another clinical study and received active drug within 30 daysor 5 half-lives of the drug prior to screening;

20. Subjects is pregnant, lactating, or planning to be pregnant;

21. Subjects have a known history of hypersensitivity or intolerance to anti-IL-5 mabsor other biological agents or previous failure of IL-5/IL-5R therapy;

22. Other conditions unsuitable for participation in the study per investigatorjudgement.