Perioperative Treatment of Hepatoid Adenocarcinoma of Stomach

Prospective, Single-arm, Single-center Phase II Clinical Study of Perioperative Precision Treatment for Locally Advanced Hepatoid Adenocarcinoma of Stomach

The goal of this clinical trial is to learn if treatment modality including Disitamab Vedotin （RC48）, Oxaliplatin，Tegafur,Gimeracil and Oteracil Porassium Capsules （SOX）and Sindillimab works to treat locally advanced hepatoid adenocarcinoma of stomach. It will also learn about the safety of this modality. The main aim it aims to achieve are:

• To evaluate the perioperative efficacy of RC48 combined with sindillizumab and SOX in the treatment of locally advanced HER2-expressing hepatoid adenocarcinoma of stomach
• To evaluate the safety and long-term benefits of RC48 combined with sindillizumab and SOX regimens in perioperative treatment of locally advanced HER2-expressing hepatoid adenocarcinoma of stomach

Participants will:

• Preoperative treatment with RC48, SOX and sindillizumab for 4 cycles
• Radical surgery after 4-6 weeks of the preoperative treatment
• Adjuvant treatment with RC48, Tegafur,Gimeracil and Oteracil Porassium Capsules and sindillizumab for 4 cycles

Inclusion Criteria:

• The histological type of gastric hepatoid adenocarcinoma was confirmed by pathological biopsy；
• HER2 expression (Immunohistochemistry: 1+,2+,3+);
• Patients with clinical stage II-III;
• Those who are expected to complete R0 excision;
• ECOG score 0~1;
• Generally in good condition, perioperative treatment and surgical resection can be tolerated;
• Patients were enrolled voluntarily.

Exclusion Criteria:

• Combined with other malignant tumors (excluding thyroid papillary carcinoma, facial basal cell carcinoma and other low-grade malignant tumors); -Patients with obstruction, bleeding, etc. who need surgical intervention after evaluation by clinicians;
• dMMR/MSIH status；
• Received other anti-tumor therapy before enrollment.