This study was a single-center, randomized, double blind, placebo-controlled, single-dose, dose-increasing study to evaluate the safety, tolerability, PK characteristics, PD effect, and immunogenicity of CM338 injection administered intravenously or subcutaneously at different doses in healthy subjects.

The study included screening period, baseline period, administration and hospitalization observation period, and safety follow-up period.

Sixty-six healthy volunteers will be enrolled and randomized into 8 groups.

Inclusion Criteria:

• with the ability to understand this study and voluntarily sign the informed consent form.
• 18 to 65 years of age.
• with normal or abnormal without clinically significance on medical history, vital signs, physical examination, 12-lead ECG, laboratory examination, chest X-ray, and abdominal color ultrasound, etc.
• able to communicate with the researchers and follow the requirements specified in the protocol.
• agree to use effective contraceptive methods from signing the ICF to 6 months after the administration.

Exclusion Criteria:

• plan to conduct any major surgery during the study.
• known allergy to monoclonal antibody drugs or other related drugs, or to the excipients of CM338 injection.
• with any clinical history including serious diseases or circulatory system, endocrine system, nervous system, blood system, immune system, mental system and metabolic abnormalities.