Due to the COVID-19 epidemic situation, the sponsor has decided to terminate the project.

An open-label, single-ascending dose phase I study to evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of STSA-1002 combined with STSA-1005 in healthy subjects.

Inclusion Criteria:

• Healthy subjects, aged ≥ 18 but ≤ 45, male and female;
• Weight: Male≥50.0kg, Female ≥ 45kg; Body mass index: 19.0-26.0 kg/m2, inclusive;
• Subjects (including their partners) must take effective contraceptive measures and have no birth plan or sperm or egg donation plan during the trial period and within 6 months after the end of the last administration;
• The subjects were aware of the risks of the trial, voluntarily participated in the study and signed the informed consent form (ICF).

Exclusion Criteria:

• Have a history of serious disease (including but not limited to gastrointestinal, renal, hepatic, neurological, hematological, endocrine, neoplastic, pulmonary, immune, psychiatric or cardiovascular diseases) or have undergone any major surgery within 2 months prior to screening;
• The investigators determined that abnormalities in pre-enrollment physical examinations, laboratory tests, and trial-related tests were clinically significant;
• A definite history of food or drug allergies;
• Positive screening test results for human immunodeficiency virus (HIV) antibodies, syphilis-specific antibody, hepatitis B surface antigen (HBsAg) or hepatitis C antibody (HCVAb);
• History of tuberculosis; or combined with T-SPOT.TB results, low-dose chest CT comprehensive evaluation of tuberculosis infection;
• Hemoglobin was lower than the lower limit of normal value during the screening period;
• Smoking more than 5 or equivalent cigarettes per day in the 3 months before screening;
• Regular drinkers in the 6 months prior to screening, i.e. those who have consumed more than 2 units of alcohol per day (1 unit =360ml beer or 45ml spirits with an alcohol concentration of 40% or 150ml wine) in the 6 months prior to screening or have a positive alcohol test result;
• Subjects with a history of substance abuse within 1 year before screening or have a positive drug test result;
• Blood loss or blood donation > 400ml three months before screening, or blood transfusion history within 4 weeks before inclusion;
• Participate in clinical trials of new drugs or vaccines as a subject within 3 months prior to screening；
• Vaccination was given within 1 month before screening or planned between the study period and 2 months after the end of the study;
• Use of medications that may affect immune function in the 6 months prior to screening or any monoclonal antibody or biologic treatment in the 3 months prior to screening and use of prescription drugs/over-the-counter drugs or herbal medicines in the 14 days prior to screening；
• Drink more than 5 cups of coffee, tea or cola (150ml or more per cup) daily within 3 months before screening;
• Pregnant or lactating women;
• A history of blood and needle sickness；
• Other circumstances in which the investigator considers it inappropriate to participate in the study.