A Clinical Study of BioTTT001 in Combination With SOX and Toripalimab in Patients With Gastric Cancer

Inclusion Criteria: 1. Male or female, age≥ 18 years； 2. Patients with a diagnosis of gastric cancer by histopathology or cytology, accompanied by peritoneal metastasis, without systemic therapy, or for patients who have received neoadjuvant/adjuvant chemotherapy before, the time from last treatment to disease recurrence \> 6 months; 3. Tumor Her2 negative (IHC 0/1＋ or IHC 2＋ and FISH-). 4. At least one measurable lesion according to the Response Evaluation Criteria in Solid Tumors （RECIST) 1.1; 5. WBC≥3.0×10\^9 /L; ANC≥1.5×10\^9 /L; HB≥90 g/L; PLT≥75×10\^9 /L; 6. ALT and AST≤3×ULN (≤5×ULN with liver metastasis); ALB≥20g/L; Cr≤1.5×ULN or CCr\>50 mL/min; TBIL≤1.5×ULN; APTT≤1.5×ULN and INR or PT≤1.5×ULN (without anticoagulation therapy) 7. LVEF≥50%; male QTc≤450 mms, female QTc≤470 mms; 8. ECOG 0\~1； 9. Expected survival ≥ 3 months; 10. Consent to contraception； 11. Understand and voluntarily sign a written ICF and be willing to comply with all trial requirements. Exclusion Criteria: 1. History of other malignancies (except cured basal cell skin cancer, cervical carcinoma in situ etc.) within 5 years before study drug administration; 2. Patients with central nervous system metastases with clinical symptoms; 3. Patients who have been treated with high-dose systemic corticosteroids (prednisone \> 10 mg/day or equivalent doses) or other immunosuppressants within 2 weeks before the first dose of BioTTT001; 4. Previous treatment with other adenovirus drugs within 28 days before the first dose of BioTTT001; 5. Patients who have undergone any major surgery (except needle biopsy, etc.) or severe trauma within 14 days before the first dose of BioTTT001; 6. Patients who have not recovered from the adverse reactions of previous treatments (the treatment-related toxicity ≤ grade 2, except for alopecia ); 7. Patients with primary immunodeficiency; 8. Patients with active autoimmune diseases (such as systemic lupus erythematosus, rheumatoid arthritis, etc.), except type 1 diabetes, hypothyroidism that only needs hormone replacement therapy, and skin diseases that do not need systemic treatment (such as vitiligo, psoriasis or alopecia); 9. Patients with active infection requiring systemic anti-infective therapy; 10. HBsAg positive, and blood HBV DNA≥100 IU/mL; anti-HCV positive; HIV positive; active syphilis; 11. Patients with active tuberculosis or drug-induced interstitial lung disease； 12. Patients with active inflammatory bowel disease ； 13. NYHA≥ grade 3； 14. Known allergy to the investigational drug or its components; 15. Patients with prior organ transplants; 16. Pregnant or lactating women; 17. Other reasons judged by the investigator.