It is designed for Multi-center, double-masked, randomized, placebo- control study with dose escalation phase I trial to evaluate the safety, tolerability, PK and immunogenicity profiles of a single intravenous injection of IBI311 in healthy volunteers.

Inclusion Criteria:

1. Willing and able to sign informed consent form and comply with visit and study procedures per protocol.
2. Male or female subjects with age of 18~45 yrs.
3. Female subjects of childbearing age or male subjects with childbearing age female partner agree to take effective contraceptive measures from the screening period to 120 days after the end of treatment.

Exclusion Criteria:

1. Have a history of or any evidence of chronic diseases of liver, kidney, cardiovascular, nervous/mental, digestive tract, respiratory, urinary and endocrine systems.
2. Have received prior treatment with another anti-IGF-1R monoclonal antibody.
3. History of drug, alcohol, or chemical abuse within 6 months prior to screening.
4. History of positive HIV antibody, HCV antibody, Syphilis check, HBV positive during screening period.
5. Receipt of a live vaccine within 180 days prior to screening or expected to receive live vaccine during study period.
6. History of recurrent significant infection or history of recurrent bacterial infections.
7. Must not have a history of tinnitus or hearing impairment.
8. Must not have received an investigational agent for any condition within 90 days.
9. Female volunteers must not be pregnant or lactating.