This is a first in human(FIH) study to characterize the safety, tolerability, pharmacokinetics (PK), immunogenicity and anti-tumor activity of AK109, an anti-VEGFR2 monoclonal antibody, as a single agent in adult subjects with advanced solid tumor.

Inclusion Criteria:

• Have signed written informed consent form voluntarily.
• Histologically or cytologically documented advanced solid tumor that is refractory/relapsed/intolerant to standard therapies, or for which no effective standard therapy is available, or subject refuses standard therapy.
• Have radiologically measurable disease based on RECIST 1.1
• ECOG of 0 or 1.
• Estimated life expectancy of ≥3 months.
• Adequate organ function.
• Have agreed to take effective contraception from the date of signing the informed consent form until 120 days after the last administration.

Exclusion Criteria:

• have been diagnosed other advanced tumors within 2 years before the first use of the study drug, except for the cured localized tumors.
• with active central nervous system metastasis, cancerous meningitis, or spinal cord compression.
• Prior use of any anti-VEGF or anti-VEGFR antibodies.
• Receipt of anti-tumor treatment, other study drug, major surgery, or serious infection within 4 weeks prior to C1D1 (Cycle 1 Day1, the first dose of study drug).
• Have received central venous catheterization within 7 days prior to C1D1.
• Severe or uncontrolled cardiovascular and cerebrovascular diseases.
• Uncontrolled hypertension.
• have a high risk of bleeding.
• Uncontrolled gastrointestinal diseases.
• Uncontrolled pleural/pericardial or peritoneal effusion.
• Have occurred any thromboembolic event, non-gastrointestinal fistula or female genital tract fistula within 6 monthsprior to C1D1.
• With cirrhosis of Child-Pugh B or C.
• Active or unstable viral hepatitis; or active tuberculosis.
• Known history of allogeneic organ transplantation or allogeneic hematopoietic stem cell transplantation.
• received live vaccines prior 30 days within the first dose.
• take apart in other clinical studies at the same time.
• known to be allergic to any component of AK109, other monoclonal antibodies or any therapeutic protein.
• mental illness, drug abuse, or alcohol dependence that may affect compliance with the test requirements.
• Any treatment risk or condition that interferes with the study by the investigator judged.