A Study to Evaluate the Efficacy and Safety of AK120 in the Treatment of Subjects With Moderate-to-severe Asthma

Key Inclusion Criteria: 1. Male or female subjects aged ≥18 years old and ≤75 years old; 2. Asthma was diagnosed ≥ 12 months before screening, current stable treatment with medium-to-high-dose inhaled glucocorticoids plus up to two additional controllers ≥ 3 months; 3. Blood eosinophil≥ 200 cells per microliter within 6 months before screening; 4. During the screening, 40% of the predicted normal value \< pre-bronchodilator FEV1 \< 80% of the predicted normal value, within 12 months before randomization, reversible airflow restriction was recorded; 5. Asthma was inadequately controlled; 6. For women with childbearing potential, they are not pregnant or lactating, and the subjects and their partners voluntarily take effective contraceptive measures judged by the investigators during the treatment and at least 3 months after last dose. Key Exclusion Criteria: 1. Subjects with lung diseases other than asthma, which may affect the subject's health or end point evaluation of the study; 2. Subjects had severe exacerbation events or systemic glucocorticoids usage within 1 month before randomization; 3. Respiratory tract infection and any serious infection within 1 month before randomization; 4. Subjects with parasitic infection, active tuberculosis infection, Hepatitis B, hepatitis C, human immunodeficiency virus (HIV) or syphilis positive confirmation test; 5. Known or suspected history of immunosuppression; 6. History of malignant tumors; 7. A history of smoking: those who had quit smoking for ≤ 6 months before screening, or smoking history \> 10 pack per year; 8. Previous treatment with interleukin-4 (IL-4) or interleukin-13 (IL-13) inhibitors, and inadequate washout period of other biologic therapy; 9. Allergen immunotherapy within 3 months before randomization; 10. Progressive or uncontrolled other diseases or any other conditions or abnormal laboratory tests for which the investigator assess that the subjects are not suitable to enrol in the study.