A Study to Evaluate the Long-term Safety, Pharmacodynamics and Efficacy of SHR-1703 in Eosinophilic Asthma Patients

Inclusion criteria

• At least 18 years of age, Male or Femal.
• A minimum weight of 40kg.
• Subjects with the clinical features of asthma that meets the diagnostic criteria of the "Guidelines for the Prevention and Treatment of Bronchial Asthma (2020 Edition)" and has a medical history of at least 1 year.
• Documentation of current asthma controller medication [medium or high dose ICS and at least one of additional controller such as long-acting muscarinic antagonist (LAMA), long-acting beta2-agonist (LABA) and leukotriene receptor antagonist (LTRA)] for at least 1 stable month before first administration of SHR-1703.
• At least one confirmed history of exacerbation within one year of initial administration of SHR-1703, occurring during the use of medium and high daily dose ICS.
• Absolute count of eosinophils must be ≥0.15×109/L at visit 0 and visit 1.
• A pre-bronchodilator FEV1 <85% and ≥30% predicted at visit 0 and visit 1.
• Female subjects with fertility agree to have no plan pregnancy and voluntarily adopt high-efficiency contraception measures from signing the informed consent form to 14 months after the last dose of SHR-1703, and male subjects with fertility as partners agree to have no plan pregnancy and voluntarily adopt high-efficiency contraception measures between the first dose of SHR-1703 and the last visit in the study.
• Subjects must be able to give written informed consent prior to participation in the study.

Exclusion criteria

• Presence of a clinically important lung condition. This includes but is not limited to current infection, bronchiectasis, pulmonary fibrosis or a history of lung cancer.
• A known immunodeficiency.
• Presence of a clinically significant and uncontrolled serious cardiovascular and cerebrovascular disease, including but not limited to myocardial infarction, unstable angina, heart failure, stroke, and subarachnoid haemorrhage.
• Within the first 4 weeks before visit 0, presence of exacerbation of allergic rhinitis or sinusitis, or a history of infections with clinical significance and/or requiring clinical intervention, including but not limited to respiratory infections.
• A known parasitic infection within the first 6 months before visit 0.
• A malignancy history within the first 5 years before visit 0 (Subjects that had localized basal carcinoma of the skin or cervical carcinoma in situ which was resected for cure will not be excluded).
• Blood donation or significant blood loss (≥ 400ml) within the first 4 weeks before visit 0, or infusion of blood products or immunoglobulins.
• Use systemic immunosuppressants (excluding systemic glucocorticoids used for asthma treatment and for non asthma treatment for less than 3 days) or immunomodulators, or biologics or Th2 cytokine inhibitors, including but not limited to methotrexate, cyclosporine, interferon-α, anti IL-5 monoclonal antibodies (including SHR-1703), anti IL-4R monoclonal antibodies, anti TSLP monoclonal antibodies, anti IgE monoclonal antibodies, metformin, etc., and within 5 half-lives of the drug before the first administration (refer to the longer drug instructions; for those with unknown half-lives, 12 weeks before the first administration shall prevail);
• Subjects who have previously participated in any study and received Investigational Product within the first 30 days before visit 0.
• There was a surgical plan or other treatment measures that the researcher believed may affect the subject's evaluation during the study period.
• Laboratory examination shows obvious abnormalities at visit 0 and visit 1:

• White blood cell count (WBC) <3.0×109/L;
• Hemoglobin≤90g/L；
• Platelet<100×109/L；
• Alanine aminotransferase (ALT)>2×ULN (upper limit of normal);
• Aspartate aminotransferase (AST) >2×ULN；
• Total bilirubin (TBIL)>1.5×ULN;
• Prothrombin time (PT) >ULN+3s；
• Creatinin>1.5×ULN;
• Active hepatitis B (positive for hepatitis B virus deoxyribonucleic acid (HBV DNA) in peripheral blood), or positive for hepatitis C virus antibody, or positive for human immunodeficiency virus (HIV) antibody, or positive for treponema pallidum antibody；
• ECG QTc>450ms or other clinically significant abnormal results that may pose significant safety risks to the subjects at visit 0 or visit 1；
• A history of drug addicts or substance abuse within 1 years prior to Visit 0；
• Subjects who are pregnant (positive HCG test at visit 0 or visit 1) or breastfeeding should not be enrolled if they plan to become pregnant during the time of study participation；
• Subjects with a known allergy or intolerance to anti IL-5 monoclonal antibody or other biologic；
• Other reasons determined by the researcher as unsuitable for participation in the study.