FLOT Combined With PD-1 in the First-line Treatment of Patients With Advanced Gastric Cancer and Peritoneal Metastasis

In this study, patients with advanced gastric adenocarcinoma whose peritoneal metastasis and peritoneal nodule pathologically confirmed metastasis and/or exfoliative cytology were confirmed as the clinical stage of peritoneal metastasis, who had not received treatment before, were invited to participate in the study.To evaluate the surgical conversion rate and tumor regression grade (TRG grade) of patients with stage gastric cancer with peritoneal metastasis using docetaxel, oxaliplatin, fluorouracil (FLOT regimen) combined with teriprizumab (PD-1).

The study drugs in this study are docetaxel, oxaliplatin, 5-FU, leucovorin, tigio capsules and teriprizumab.

Dosage and dosing regimen for all research phases:

The enrolled patients will receive 4 cycles of FLOT regimen + teriprizumab treatment before surgery, and every 2 weeks is a treatment cycle (Q2W). The specific plan is as follows.

* FLOT: Docetaxel 50mg/m2 ivd d1 + oxaliplatin 85mg/m2 ivd d1 + leucovorin 200mg/m2 ivd d1 + 5-FU 2600mg/m2 civ 24h Q2W
* Treprizumab 3mg/kg, intravenously administered on the first day of each cycle, Q2W If the transformation is successful, the patient undergoes R0 surgical resection of D2 lymph node dissection for gastric cancer in accordance with the "Japanese Gastric Cancer Treatment Guidelines. Physician's Edition. 4th Edition". After the operation, the patient will continue to receive 4 cycles of FLOT treatment + Teripril Anti-treatment, the treatment plan is the same as before.

After completing the 4 cycles of treatment, oral Tiggio Capsule (S-1) and Teriprizumab were maintained for 1 year. The specific plan is as follows.

* Tiggio capsule (S-1) 40-60mg (BSA\<1.25 m2: 40mg, 1.25 m2≤BSA≤1.5 m2: 50mg, BSA\> 1.5 m2: 60mg) po bid d1-14 Q3W, continuous treatment for 1 year;
* Teriprizumab 240mg, intravenously, given on the first day of each cycle, Q3W, continuous treatment for 1 year.

Eligibility Criteria:
Inclusion Criteria:

1. Informed consent of the patient;
2. 18 years old \<age \<80 years old;
3. The primary gastric lesion was diagnosed as gastric adenocarcinoma by endoscopic biopsy histopathology (papillary adenocarcinoma pap, tubular adenocarcinoma tub, mucinous adenocarcinoma muc, signet ring cell carcinoma sig, poorly differentiated adenocarcinoma por);
4. The clinical stage of laparoscopic exploration is peritoneal metastasis, peritoneal nodule pathologically confirmed metastasis and/or exfoliated cytology test positive for advanced gastric cancer patients;
5. Preoperative ECOG \[Using the ECOG scoring standard Zubrod-ECOG-WHO (ZPS, 5-point method) developed by the Eastern Cooperative Oncology Group (ECOG)\] Physical State Score 0/1;
6. Preoperative anesthesia risk score sheet (ASA score sheet) I-III;

Exclusion Criteria:

1. The pathology of the peritoneal nodule confirmed no metastasis, and the exfoliated cytology test was negative;
2. Pregnant or lactating women;
3. Suffer from severe mental illness;
4. Preoperative imaging or intraoperative exploration revealed that there have been distant blood metastases in the liver, lungs, and brain;
5. A history of other malignant diseases within 5 years;
6. A history of allergies to any component of teriprizumab, docetaxel, oxaliplatin, and fluorouracil;
7. A history of continuous systemic corticosteroid therapy within 1 month;
8. Complications of gastric cancer (bleeding, perforation, obstruction) requiring emergency surgery;
9. A history of unstable angina or myocardial infarction, or a history of cerebral infarction or cerebral hemorrhage within 6 months, and a lung function test FEV1 \<50% of the expected value;
10. Have received any of the following treatments:

    1. Have received anti-PD-1 or anti-PD-L1 antibody therapy in the past;
    2. Have received any investigational drug treatment within 4 weeks before using the drug for the first time;
    3. Enroll in another clinical study at the same time, unless it is an observational (non-interventional) clinical study or an interventional clinical study follow-up;
    4. Receive the last dose of anti-cancer treatment (including radiotherapy) within 4 weeks before the first use of the study drug;
    5. Those who have been vaccinated with anti-tumor vaccines or the study drugs have been vaccinated with live vaccines within 4 weeks before the first administration;
    6. Those who have undergone major surgery or trauma within 4 weeks before using the study drug for the first time.