A Study of ES009 in Subjects With Locally Advanced or Metastatic Solid Tumors

Inclusion Criteria:

• Capable of giving signed informed consent.

• Histological or cytological documentation of unresectable locally advanced ormetastatic solid tumors, if 1) disease has progressed despite standard therapy, andno further standard therapy exists; or 2) standard therapy has proven to beineffective or intolerable or is considered inappropriate.

• At least one measurable lesion per RECIST v1.1.

• Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0-1.

• Life expectancy of at least 12 weeks.

• Adequate hematologic, hepatic, renal and coagulation function per protocol.

• Male and female subjects of childbearing potential must be willing to completelyabstain or agree to use a highly effective method of contraception per protocol.

Exclusion Criteria:

• Any prior therapy targeting LILRB2.

• Receipt of any investigational therapies within 28 days or 5 half-lives prior to thefirst dose of study drug.

• Prior treatment with the following therapies:• Anticancer therapy within 28 days or 5 half-lives of the drug prior to the first dose of study drug, whichever isshorter. Exception: hormonal replacement therapy.• A wash out of at least 2 weeksbefore the start of study drug for radiation to the extremities and 4 weeks forradiation to the chest, brain, or visceral organs is required.

• Prior allogeneic or autologous bone marrow transplantation or solid organtransplantation.

• Toxicity from previous anticancer treatment per protocol.

• Treatment with systemic immunosuppressive medications within 4 weeks prior to thefirst dose of study drug with certain exceptions.

• Subjects who received transfusion of blood products (including platelets or redblood cells), G-CSF, GM-CSF, recombinant erythropoietin, or recombinantthrombopoietin within 14 days prior to the first dose of study treatment.

• Major surgery within 4 weeks prior to the first dose of study treatment.

• Live vaccine therapies within 4 weeks prior to the first dose of study treatment.

• Recent history of allergen desensitization therapy within 4 weeks prior to the firstdose of study treatment.

• Known allergies to CHO-produced antibodies.

• Invasive malignancy or history of invasive malignancy other than disease under studywithin the last two years with certain exceptions.

• CNS metastases with certain exceptions.

• Active autoimmune disease or documented history of autoimmune disease that requiredsystemic steroids or other immunosuppressive medications.

• Active interstitial lung disease (ILD) or pneumonitis requiring treatment withsteroids or other immunosuppressive medications.

• Active infection requiring systemic therapy, known human immunodeficiency virus (HIV) infection, or positive test for hepatitis B active infection (HBsAg) orhepatitis C active infection (hepatitis C antibody).

• Current active liver or biliary disease (with the exception of Gilbert's syndrome orasymptomatic gallstones, liver metastases, or otherwise stable chronic liver diseaseper investigator assessment).

• History or evidence of cardiac abnormalities.

• Pregnant or nursing females.

• Any known, documented, or suspected history of illicit substance abuse that wouldpreclude subject from participation, unless clinically justified.

• Any other disease or clinically significant abnormality in laboratory parameters,including serious medical or psychiatric illness/condition, which in the judgment ofthe Investigator might compromise the safety of the subject or integrity of thestudy, interfere with the subject participation in the trial or compromise the trialobjectives.

• Involvement in the planning and/or conduct of the study (applies to both Sponsor/CROstaff and staff at the study site)

• Judgment by the Investigator that the subject is unlikely to comply with studyprocedures, restrictions and requirements.