Perioperative Treatment of Resectable Adenocarcinoma of Esophagogastric Junction by Immunotherapy (Adebrelimab) Combined With Chemotherapy (XELOX): a Prospective, Single-center, Feasibility Study

Inclusion Criteria:

• Sign on the informed consent form (ICF)

• Histologically confirmed esophagogastric junction Adenocarcinoma (AEG, Type SiewertI/II/ III), the stage is locally advanced cT1b-2N+ or T3-4Nany that the investigatorjudges it to be resectable (1. CT or MRI assessment shows no invasion of adjacentorgans or tissues, 2. No peritoneal metastasis occurs, 3. There are surgicalindications) (Note: If bone lesions are suspected, a bone scan is required; ifperitoneal carcinomatosis is suspected, laparoscopy is required to confirm; if T3-T4subjects have diffuse tissue types, diagnostic laparoscopy is also required))

• No previous systematic treatment

• At least one measurable lesion according to RECIST 1.1.

• ECOG PS: 0-1

• The functions of important organs meet the following requirements：Absoluteneutrophil count ≥ 1.5 × 109/L； Platelet ≥ 100 × 109/L； Hemoglobin ≥ 90g / l; ALTand AST ≤ 2.5 times ULN; TBIL ≤ 1.5 times ULN; Serum creatinine ≤ 1.5 times ULN orcreatinine clearance ≥ 60ml / min; INR ≤ 1.5, APTT ≤ 1.5 times ULN; No obviousabnormality on electrocardiogram.

• Male subjects and women of childbearing age must take contraceptive measures fromthe first dose to the last 3 months of use of the study drug.

Exclusion Criteria:

• Histologically confirmed Squamous cell carcinoma or mixed type.

• Distant metastasis: If peritoneal cancer or ascites is suspected by imaging,histological or cytological confirmation such as laparoscopic exploration isrequired.

• Medical history and complications: 1.Having contraindications to surgical resectionof esophagogastric junction cancer 2.Having any known active autoimmune diseases 3.Having any complications that require systemic treatment with glucocorticoids suchas prednisone (>10 mg/day) or have used immunosuppressive drugs within 14 daysbefore the first dose

• Having received tumor vaccines or other immune-activating anti-tumor drugs (such asinterferon, interleukin, thymosin or immune cell therapy) within 1 month before thefirst dose 4.Having participated in other clinical trials or have received druginterventions from other clinical trials within 4 weeks before the first dose 5.Having other malignant tumors that need treatment 6.Having a history of severecardiovascular disease 7.Having a known history of allogeneic organ transplantationand allogeneic hematopoietic stem cell transplantation

• Severe allergic reaction to drugs (Adbrelimab, Capecitabine, Oxaliplatin).

• The subjects were innate or acquired immunodeficiency (such as HIV), or activehepatitis (hepatitis B reference: HBsAg) positive; Hepatitis C reference: HCVantibody positive.

• According to the judgment of the researcher, the subject has other factors that maylead to the forced midway termination of this study, such as other serious diseases (including mental diseases) requiring combined treatment, serious laboratoryabnormalities, accompanied by family or social factors, which will affect the safetyof the subject, or the collection of data and samples.