A Phase I Study of CS2009 in Participants With Advanced Solid Tumors

Inclusion Criteria:

• Evidence of a personally signed and dated informed consent document.

• Willing and able to comply with scheduled visits, treatment plan, laboratory tests,and other study procedures.

• Age ≥ 18 years on the day of signing informed consent.

• Pathologically or cytologically confirmed, unresectable advanced solid tumors,including but not limited to non-small cell lung cancer (NSCLC), small cell lungcancer (SCLC), renal cell carcinoma (RCC), hepatocellular carcinoma (HCC), gastriccancer (GC), ovarian cancer (OC), cervical cancer (CC), etc.

• Failure of established standard of care for advanced disease, or no availablestandard of care, or intolerance to standard of care.

• Participants with at least one measurable lesion as defined per RECIST v1.1 solidtumor.

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

• Adequate organ function.

• Fertile male participants and female participants of childbearing potential must bewilling to use an effective method of birth control from providing signed consentand for 180 days after the last investigational product administration.

• Female participants of childbearing potential must have a negative pregnancy test ≤ 7 days prior to the first dose of the investigational product.

Exclusion Criteria:

• History of a second malignancy active within the previous 3 years except for locallycurable cancers that have been apparently cured.

• Known primary central nervous system (CNS) tumor or solid tumor CNS metastasis thatis either symptomatic, untreated, or requires therapy.

• Presence of uncontrolled pleural effusion, pericardial effusion, or ascitesrequiring repeated drainage within 4 weeks prior to the first dose ofinvestigational product.

• Receipt of systemic corticosteroid treatment or any other form of immune suppressingtreatment within 7 days prior to the first dose of investigational product.

• Active or prior history of definite inflammatory bowel disease.

• History of (non-infectious) interstitial lung disease (ILD)/pneumonitis thatrequired steroids, or presence of active or suspected ILD/pneumonitis.

• Active infections requiring systemic therapy within 2 weeks prior to the first doseof investigational product.

• Positive for human immunodeficiency virus (HIV) or presence of acquired immunedeficiency syndrome (AIDS).

• Active Hepatitis B or C infection.

• Active pulmonary tuberculosis (TB).

• Major surgery, chemotherapy, definitive radiotherapy, target therapy, immunotherapy,or other anti-cancer therapy within 21 days prior to the first dose ofinvestigational product.

• Palliative radiotherapy within 14 days prior to the first dose of investigationalproduct, or receipt of radioactive drug within 56 days prior to the first dose ofinvestigational product.

• Administration of live vaccine within 28 days prior to the first dose ofinvestigational product.

• History of allogeneic organ transplantation and allogeneic hematopoietic stem celltransplantation.

• Receipt of antitumor Chinese herbal preparations or Chinese patent medicine within 7days prior to the first dose of investigational product.

• Receipt of any other investigational drugs within 21 days prior to the first dose inthis trial.

• History of hypersensitivity or idiosyncrasy to the excipients of the study drug orany monoclonal antibody.

• Any toxic effects of prior therapy or surgical procedures unresolved to baselineseverity or NCI-CTCAE Version 5.0 Grade ≤ 1.

• Active alcohol or drug abuse.

• Female participants who are pregnant or breastfeeding.

• Other acute or chronic medical or psychiatric conditions that may increase the riskassociated with study participation or investigational product administration.