The purpose of this study is to evaluate the pharmacokinetic similarity of AK104 with different manufacturing process in healthy male subjects. Another purpose is to determine safety, and immunogenicity of AK104 with different manufacturing process.

Inclusion Criteria:

1. Males aged 18 to 45;
2. Body Mass Index (BMI) is 19.0~28.0 kg/m2, and body weight is 50.0~80.0kg ;
3. Signing informed consent form before the trial and having a full understanding of the trial content, process and possible adverse reactions;
4. Able to complete the study according to the requirements of the study protocol.

Exclusion Criteria:

1. Those with a history of digestive tract, respiratory, cardiovascular, endocrine, urinary, neurological, hematological, metabolic and other systemic diseases;
2. Those with a history of autoimmune diseases;
3. Those with a history of malignant tumor, unless it is a skin squamous cell carcinoma, basal cell carcinoma or cervical cancer in situ that has been successfully resected and has no evidence of metastasis;
4. Regular drinkers within 6 months prior to screening;
5. Those who are suspected or confirmed to be allergic or have had severe drug or food allergy reactions in the past, have a clear history of allergies and/or are allergic to the study drug or its components after inquiries;
6. Those who have used anti-PD-1/PD-L1 or/and anti-CTLA-4 drugs in the past;
7. Those who have been vaccinated with live or attenuated-live vaccines within 3 months before screening, or who are expected to receive vaccines during the study period;
8. Those who lost blood, donated blood or received any blood product transfusion of ≥400 ml within 3 months before screening;
9. Those who received major surgery or hospitalization due to illness within 3 months before screening;
10. Abnormal laboratory tests with clinical significance at screening;
11. Positive drug screening result;
12. Have a childbirth plan within 6 months from the screening period to the trial drug administration, or who are unwilling to take the contraceptive measures specified in the protocol during the trial period.