ASKB589 in Combination With CAPOX and Sintilimab in Patients With Advanced, and Unresectable G/GEJ Cancer.

Inclusion Criteria:

1. Histopathologically confirmed unresectable locally advanced, recurrent, or metastaticadenocarcinoma of the gastric and gastroesophageal junction currently ineligible forsurgery and radical radiotherapy.
2. Investigators determined that the present situation of the patient justifieschemotherapy plus immunotherapy as first-line treatment.
3. Tumor tissue samples are CLDN18.2 positive detected by central laboratory
4. ECOG performance status 0-1.
5. The results of the laboratory tests must meet all criteria
6. Life expectancy of at least 3 months.

Exclusion Criteria:

1. Known active central nervous system metastasis or suspected cancerous meningitis;
2. There are moderate to large amounts of abdominal and pleural fluid.
3. The presence of clinically uncontrollable third interspace fluid；
4. Patients with any other malignant tumors within the past 5 years.
5. Applicable to anti-HER-2 drug therapy；
6. Anti-CLDN18.2 antibody, anti-PD-1 antibody, or drug therapy at any time in the past；
7. Patients have received antitumor therapy during the first 4 weeks before study druguse;
8. Pregnant or lactating women; or women of childbearing age who have a positive bloodpregnancy test during screening period; or women of childbearing age and their spouseswho are unwilling to take effective contraceptive measures during the period of thisclinical trial and within 6 months after the end of the clinical trial;