PD-1 Monoclonal Antibody Combined With FLOT Regimen for Neoadjuvant Therapy of Gastric Adenocarcinoma

• Informed consent has been signed;
• Only patients aged 18-75 were enrolled;
• Pathologically confirmed gastric adenocarcinoma (cT4 or/and N+M0, MDT considers perioperative treatment necessary) :Bone scan should be performed if bone metastasis is suspected.If peritoneal metastasis is suspected, laparoscopy should be performed;
• No previous cytotoxic chemotherapy or targeted therapy;
• No previous local resection of the tumor;
• ECOG 1 or less;
• Tumor specimens capable of detecting PDL-1 and MSI status are available.The detection of PDL-1 and MSI will be conducted after random grouping.This test requires the patient to provide a paraffin-embedded biopsy specimen;
• Leukocyte ≥ 4×109/L, platelet ≥ 100×109/L without transfusion, absolute value of neutrophils (ANC) without granulocyte stimulation factor ≥ 1.5×109/L, and hemoglobin≥ 90 g/L;
• Bilirubin ≤ 1.5 times of the upper limit of normal value, and rice grass and rice propyl transaminase ≤ 2.5 times of the upper limit of normal value;
• Serum creatinine ≤ 1.5 times the upper limit of normal value, or GFR>45ml/min;
• Serum albumin ≥ 25g /L (2.5g /dL);
• INR or aPTT ≤1.5 times ULN;

Exclusion Criteria:

• Allergy to any experimental drug and its excipients, or a history of severe allergy, or a contraindication to the experimental drug;
• Ahistory of autoimmune diseases or active stage;
• Previous allogeneic bone marrow transplantation or organ transplantation;
• Congenital pulmonary fibrosis, drug-induced pneumonia, organized pneumonia, or ct-confirmed active pneumonia;
• HIV test positive;
• Active hepatitis b or c;
• Active tuberculosis;
• Uncontrolled cancer pain;
• Live attenuated vaccine was injected within 4 weeks before the study began, or live attenuated vaccine was expected to be injected during the trial or within 5 months after the trial;
• Previous immunotherapy, including CTLA4, anti-pd-1, or anti-pdl1 monoclonal antibody;
• CT suggested active pulmonary inflammation;
• Systemic application of glucocorticoids or immunosuppressants within 2 weeks before the start of the trial.Inhaled glucocorticoids and glucocorticoids are allowed;
• There are taboos on hormone use;
• Severe cardiovascular disease, myocardial infection or cerebrovascular accident, arrhythmia, unstable angina within 3 months before the start of the trial;
• Uncontrolled increase in blood pressure or blood sugar;
• Other malignancies prior to 5 years, with the exception of cervical carcinoma in situ, non-melanoma skin cancer, or stage I uterine cancer;
• Known central nervous system metastases;
• Peripheral neuropathy ≥ NCI CTCAE grade 2;
• Serum albumin below 2.5 g/dL;
• Uncontrolled or symptomatic hypercalcemia;
• Infections requiring antibiotics within 14 days prior to the start of the trial;
• Chronic enteritis;
• Clinically significant active gastrointestinal bleeding;
• Non-diagnostic surgery within 4 weeks before the start of the trial;
• Any other disease where there is evidence of a need to restrict the use of the experimental drug;
• Participate in other tests within 30 days before the start of the test, or plan to participate in other tests during the test;
• Receive other experimental drugs within 28 days prior to the start of the trial;
• Pregnantor lactating women, or women who plan to become pregnant within 5months after the end of treatment.Women of childbearing age should undergo a blood pregnancy test within 7 days of the start of the trial.