Inclusion criteria
WOCBP, tumor, ≤28
TUMOR, LIVER METASTASES, DISEASE, METASTATIC DISEASE, ADENOCARCINOMA, APPENDIX
General criteria:IRB/IEC-approved written informed consent and privacy language as per national regulations (for example, Health Insurance Portability and Accountability Act (HIPAA) authorization for US sites) must be obtained from the patient or legally authorized representative (if applicable) before any study-related procedures.Patient is considered an adult (for example, ≥18 years of age in the USA) according to local regulation at the time of signing the informed consent.A female patient is eligible to participate if she is not pregnant (negative serum pregnancy test at screening; female patients with elevated serum beta human chorionic gonadotropin (βhCG) and a demonstrated non-pregnant status through additional testing are eligible) and at least one of the following conditions applies.Not a woman of childbearing potential (WOCBP) as defined in Protocol Appendix 12.3 Contraception RequirementsORWOCBP who agrees to follow the contraceptive guidance as defined in Protocol Appendix 12.3 Contraception Requirements throughout the treatment period and for 9 months after the final administration of oxaliplatin and 6 months after the final administration of all other study drugsFemale patient must agree not to breastfeed starting at screening and throughout the study period and for 6 months after the final study treatment administration.Female patient must not donate ova starting at screening and throughout the study period and for 9 months after the final administration of oxaliplatin and for 6 months after the final administration of all other study drugs.Male patient with female partner(s) of childbearing potential must agree to use contraception as detailed in Protocol Appendix 12.3 Contraception Requirements during the treatment period and for 6 months after the final study treatment administration.Male patient must not donate sperm during the treatment period and for 6 months after the final study treatment administration.Male patient with a pregnant or breastfeeding partner(s) must agree to remain abstinent or use a condom for the duration of the pregnancy or time partner is breastfeeding throughout the study period and for 6 months after the final study treatment administration.Patient agrees not to participate in another interventional study while receiving study drug in the present study.Disease-specific criteria:Patient has histologically confirmed diagnosis of G/GEJ adenocarcinoma.Patient has radiologically confirmed locally advanced unresectable or metastatic disease within 28 days before randomization.Patient has radiologically evaluable disease (measurable and/or non-measurable) according to RECIST version 1.1, per local assessment, ≤28 days before randomization. For patients with only one evaluable lesion and prior radiotherapy ≤3 months before randomization, the lesion must either be outside the field of prior radiotherapy or have documented progression after radiation therapy.Patient’s tumor expresses CLDN18.2 in ≥75% of tumor cells, demonstrating moderate-to-strong CLDN18 membranous staining as determined by central immunohistochemistry testing.Patient has a HER2-negative tumor as determined by local or central testing on a G/GEJ tumor specimen.Physical or laboratory findings:Patient has a ECOG performance status score 0 or 1.Patient has predicted life expectancy ≥12 weeks, in the opinion of the investigator.Patient must meet all of the following criteria based on the centrally or locally analyzed laboratory tests collected within 14 days before randomization. In the case of multiple sample collections within this period, the most recent sample collection with available results should be used to determine eligibility.Hemoglobin ≥9 g dlAbsolute neutrophil count (ANC) ≥1.5 × 10Platelets ≥100 × 10Albumin ≥2.5 g dlTotal bilirubin ≤1.5× upper limit of normal (ULN) without liver metastases (or <3.0× ULN if liver metastases are present)Aspartate aminotransferase and alanine aminotransferase ≤2.5× ULN without liver metastases (or ≤5× ULN if liver metastases are present)Estimated creatinine clearance ≥30 ml minProthrombin time/international normalized ratio and partial thromboplastin time ≤1.5× ULN (except for patients receiving anti-coagulation therapy)