Perioperative Chemotherapy Plus Trastuzumab Plus Toripalimab in HER2 Positive Locally Advanced Gastric or Esophagogastric Junction Adenocarcinoma

Toripalimab, 240 mg IV infusion on Day 1 of each 21 day cycle for 3 cycles prior to surgery and 3 cycles after surgery.

Trastuzumab, 8 mg/kg IV loading dose at 1st administration and then 6 mg/kg IV on Day 1 of each 21 day cycle for 3 cycles before surgery and 3 cycles after surgery. The first administration of trastuzumab after surgery should also be given at the loading dose of 8 mg/kg.

"Pre-operative treatment 4 cycles and post-operative treatment 4 cycles:~Docetaxel 50 mg/m², IV on day 1 of each 14 day cycle; Oxaliplatin 85 mg/m² , IV on day 1 of each 14 day cycle; Leucovorin 200 mg/m² or Levoleucovorin 100 mg/m², IV on day 1 of each 14 day cycle; 5-FU 2600 mg/m², IV over 24 h on day 1 of each 14 day cycle."