Efficacy and Safety of Serplulimab Combined With Chemotherapy as Neoadjuvant Treatment for Locally Advanced Gastric Cancer or Adenocarcinoma of Esophagogastric Junction

Serplulimab (Dosage form: Lyophilized powder; Unit dose strength: 4.5 mg; Route of administration: IV infusion; Storage requirements: 2-8℃. Protect from light and freezing.) Nap-paclitaxel (Dosage form: Lyophilized powder; Unit dose strength: 100 mg; Route of administration: IV infusion; Storage requirements: \<25℃. Protect from light.) S-1 (Dosage form: Capsule; Unit dose strength: 20 mg; Route of administration: Oral; Storage requirements: 20-30℃. Protect from light.) Oxaliplatin (Dosage form: Lyophilized powder; Unit dose strength: 50 mg; Route of administration: IV infusion; Storage requirements: \<25℃. Protect from light.) Surgery: All surgical procedures are performed according to the guidelines of the Japanese Research Society for the Study of Gastric Cancer.

Placebo (Dosage form: Lyophilized powder; Unit dose strength: 4.5 mg; Route of administration: IV infusion; Storage requirements: 2-8℃. Protect from light and freezing.) Nap-paclitaxel (Dosage form: Lyophilized powder; Unit dose strength: 100 mg; Route of administration: IV infusion; Storage requirements: \<25℃. Protect from light.) S-1 (Dosage form: Capsule; Unit dose strength: 20 mg; Route of administration: Oral; Storage requirements: 20-30℃. Protect from light.) Oxaliplatin (Dosage form: Lyophilized powder; Unit dose strength: 50 mg; Route of administration: IV infusion; Storage requirements: \<25℃. Protect from light.) Surgery: All surgical procedures are performed according to the guidelines of the Japanese Research Society for the Study of Gastric Cancer.