FMT+SOX+Sintilimab As First-line Treatment for Advanced Gastric Cancer

Inclusion Criteria:

• Subjects aged 18-80 (including 18 and 80 years old);

• Understand the research steps and content, and voluntarily sign a written informedconsent form;

• Non resectable Her-2 negative advanced or metastatic gastric/gastroesophagealjunction adenocarcinoma confirmed by histopathology and/or cytology, excluding allother histological types;

• At least one measurable lesion, according to RECIST 1.1 standard;

• Have not received anti-tumor treatment in the past;

• The physical status score of Eastern Tumor Collaboration Group (ECOG) was 0-1;

• Expected survival time ≥ 3 months;

• Have adequate organ and bone marrow function, laboratory examination within 7 daysprior to enrollment meets the following requirements (no blood components, cellgrowth factors, albumin or other corrective drugs are allowed within 14 days priorto obtaining laboratory examination), as follows: 1) Blood routine: absoluteneutrophil count (ANC) ≥1.5×109/L, platelet (PLT) ≥75×109/L, hemoglobin (HGB) ≥90g/L (no blood transfusion or erythropoietin dependence within 14 days); 2) Liverfunction: serum total bilirubin (TBIL) ≤2 times the upper limit of normal (ULN);Alanine aminotransferase (ALT) and/or aspartate aminotransferase (AST) ≤ 5x ULN,serum albumin ≥28 g/L; alkaline phosphatase (ALP) ≤5×ULN; 3) Renal function: serumcreatinine (Cr) ≤1.5×ULN, or creatinine clearance ≥50 mL/min (using the standardCockcroft-Gault formula) : Urine routine results showed urinary protein < 2+; Forpatients with urine protein ≥2+ at baseline,24-hour urine collection and 24-hoururine protein quantification<1g should be performed; 4) Coagulation function:International standardized ratio (INR) or prothrombin time (PT) ≤1.5 times ULN; Ifthe subject is receiving anticoagulant therapy, as long as the INR is within theintended range of anticoagulant drug use.

• For female subjects of reproductive age, a urine or serum pregnancy test should beperformed and the result is negative 3 days prior to receiving the initial studydrug administration;

• Subjects and their sexual partners are required to use a medically approvedcontraceptive method (such as an IUD, contraceptive pill, or condom) during thestudy treatment period and for 6 months after the end of the study treatment period.

Exclusion Criteria:

• Currently participating in an interventional clinical study or receiving anotherinvestigational drug or investigational device within 4 weeks prior to initialdosing;

• Received proprietary Chinese medicines with anti-tumor indications orimmunomodulatory drugs (thymosin, interferon, interleukin, etc.) within 2 weeksbefore the first administration, or received major surgical treatment within 3 weeksbefore the first administration;

• Class III - IV congestive heart failure (New York Heart Association classification),poorly controlled and clinically significant arrhythmias;

• Any arterial thrombosis, embolism or ischemia, such as myocardial infarction,unstable angina pectoris, cerebrovascular accident or transient ischemic attack,occurred within 6 months before treatment;

• Known allergic reaction to the drug in this study;

• Patients requiring long-term systemic use of corticosteroids. Patients with COPD orasthma requiring intermittent use of bronchodilators, inhaled corticosteroids, orlocal corticosteroids could be enrolled;

• Symptomatic central nervous metastases. Patients with asymptomatic BMS or BMS whosesymptoms are stable after treatment are eligible to participate in this study ifthey meet all of the following criteria: measurable lesions outside the centralnervous system; No midbrain, pontine, cerebellum, meninges, medulla oblongata orspinal cord metastasis; Maintain clinical stability for at least 2 weeks;

• Stop hormone therapy 3 days before the first dose of the study drug;

• There is an active infection requiring treatment or systemic anti-infective drugshave been used in the week prior to the first dosing;

• Has not fully recovered from toxicity and/or complications caused by anyintervention before starting treatment (i.e., ≤ grade 1 or baseline, excludingweakness or hair loss);

• Known history of human immunodeficiency virus (HIV) infection (i.e. HIV 1/2 antibodypositive);

• Untreated active hepatitis B (defined as HBsAg positive and HBV-DNA copy numberdetected greater than the upper limit of normal value in the laboratory of the studycenter);

• Active HCV-infected subjects (HCV antibody positive and HCV-RNA levels above thelower limit of detection);

• Pregnant or lactating women;

• Medical history or evidence of disease that may interfere with test results, preventparticipants from fully participating in the study, abnormal treatment or laboratorytest values, or other conditions that the investigator considers unsuitable forenrollment The Investigator considers other potential risks unsuitable forparticipation in the study.