SHR-1210 Combined With Trastuzumab , Oxaliplatin and Capecitabine for Neoadjuvant Therapy of Gastric Adenocarcinoma/Gastroesophageal Junction Adenocarcinoma

Prior treatment

• Previously received allogeneic bone marrow transplantation or organ transplantation
• Congenital pulmonary fibrosis, drug-induced pneumonia, organizing pneumonia, or CT-confirmed active pneumonia
• A live attenuated vaccine is injected within 4 weeks before the start of the study, or it is expected that a live attenuated vaccine will be injected within 5 months after the trial or the end of the trial.
• Previous use of immunotherapy, including CTLA4, anti-PD-1, or anti-PDL1 mAb
• Systemic application of glucocorticoids or immunosuppressants within 2 weeks prior to the start of the trial. Inhaled corticosteroids and mineralocorticoids are allowed
• severe cardiovascular disease, myocardial infection or cerebrovascular accident, arrhythmia, unstable angina within 3 months before the start of the test
• Infections requiring antibiotics within 14 days prior to the start of the test
• Non-diagnostic surgery within 4 weeks prior to the start of the trial 24 There is evidence of the need to limit any other disease using the test drug
  • 25\. Participate in other tests within 30 days before the start of the test, or plan to participate in other tests during the test. Accept other experimental drugs within 28 days before the start of the test 26. Women who are pregnant or lactating, or women who are planning to become pregnant within 5 months of the end of treatment. Women of childbearing age are required to undergo a blood pregnancy test within 7 days prior to the start of the trial.

Other illness

• Allergic to any test drug and its excipients, or have a history of severe allergies, or a contraindication to test drugs
• Have a history of autoimmune disease or be active
• HIV test positive
• Active hepatitis B or hepatitis C
• Active tuberculosis
• Uncontrolled cancer pain
• History of other malignant tumors 5 years ago, except for cervical cancer in situ, non-melanoma skin cancer or stage I uterine cancer
• clinically significant active gastrointestinal bleeding

Lab values

• serum albumin is less than 2.5 g/dL

Other

• Hormone use contraindications。
• Uncontrollable increase in blood pressure or elevated blood sugar
• Known central nervous system metastasis
• ≥ NCI CTCAE Level 2 Peripheral Neuropathy
• uncontrollable or symptomatic hypercalcemia
• chronic enteritis

• Signed the informed consent form
• 18-75 years old
• Pathologically confirmed gastric adenocarcinoma or gastroesophageal junction adenocarcinoma (cT4 or / and N+M0, MDT believes that perioperative treatment is required):
  • No peritoneal metastasis in CT
  • evaluated as a resectable lesion. Note: Whether there is a distant metastasis should be confirmed by CT or MR scan. If bone metastasis is suspected, a bone scan should be performed. If there is suspected peritoneal metastasis, a laparoscopy should be performed. If brain metastasis is suspected, CT or MR examination should be performed.
• Have not received cytotoxic chemotherapy or targeted therapy and local tumor resection
• HER2 immunohistochemistry 3+ and fluorescence in situ hybridization showed significant amplification
• ECOG≤1
• Tumor specimens that can be used to detect PD-L1 and MSI status can be provided. Detection of PD-L1 and MSI will be performed after enrollment. This test requires patients to provide paraffin-embedded biopsy specimens.
• White blood cells ≥ 4×109/L, platelets without blood transfusion ≥ 100×109/L, absolute neutrophil count (ANC) ≥ 1.5×109/L without granulocyte stimulating factor, hemoglobin ≥ 90 g/L
• bilirubin ≤ 1.5 times the upper limit of normal value, cereal grass and alanine aminotransferase ≤ 2.5ULN. If there is liver metastasis, the grass and alanine aminotransferase ≤ 5ULN.
• serum creatinine ≤ 1.5ULN, or GFR \> 45 ml / min
• serum albumin ≥ 25 g / L (2.5 g / dL)
• INR or APTT ≤ 1.5 ULN
• Hepatitis B surface antigen positive patients need to detect hepatitis B DNA virus quantitative detection, only patients below the upper limit of normal detection can be enrolled, and long-term use ofanti-hepatitis B virus drugs