KN026 in Patients With HER2 Expressing Gastric/Gastroesophageal Junction Cancer

The study consists of two arms as HER2 overexpression arm and HER2 expression arm and both arms will receive KN026 treatment.

Inclusion criteria

• Signed inform consent form(ICF)
• Age ≥ 18 years and ≤ 75 years, male or female
• Histologically or cytologically documented advanced gastric/gastroesophageal junction cancer HER2 overexpressing: IHC 3+ or IHC 2+ & ISH+ HER2 expressing: IHC2+ & ISH- or IHC 1+ & ISH+
• Received at least one prior standard therapy
• At least one evaluable lesion according to Response Evaluation Criteria In Solid Tumors（RECISIT） v 1.1
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
• Adequate organ function
• LVEF≥ 50% (ECHO)
• Female patients and males with partners of childbearing potential should be using highly effective contraceptive measures (failure rate of less than 1% per year). Contraception should be continued for a period of 24 weeks after dosing has been completed.
• Ability to comply with treatment, procedures and pharmacokinetics (PK) sample collection and the required study follow-up procedures

Exclusion criteria

• Accepted any other anti-tumor drug therapies within 4 weeks before fist dose
• Accepted radiotherapy within 4 weeks before enrollment
• An anthracyclines antibiotic treatment was received exceeding 320 mg/m² or other equivalent dose antharcyclines
• Subjects are eligible with clinically controlled and stable neurologic function >= 4 weeks, which is no evidence of CNS disease progression; Subjects with spinal cord compression and cancerous meningitis are not eligible
• Pregnant or nursing females；or intend pregnancy within this study period or within 6 monthes after the end of this study
• History of immunodeficiency, including HIV positive or other acquired, congenital immunodeficiency disease, or a history of organ transplantation
• Severe chronic and active infection, need to system antibiosis/antiviral treatment
• Cavity effusion (pleural effusion, ascites, pericardial effusion, etc.) are not well controlled, and need locally treatment or repeated drainage
• Even with peripheral or central venous nutritional support, unintentional weight loss ≥5% within 1 month before the first medication