This is a Randomized, Double-Blind, Phase II/III Clinical Study of the Efficacy and Safety of Sintilimab Combined with Chemotherapy With or Without Ipilimumab N01 in Perioperative Treatment of Resectable Gastric/Gastroesophageal Junction Adenocarcinoma.
Signed written Informed Consent Form (ICF) and ability to comply with protocol-specified visits and related procedures.
Age ≥ 18 years.
Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1.
Expected survival ≥ 6 months.
Histologically or cytologically confirmed other pathologic types (e.g., squamous cell carcinoma, sarcoma, undifferentiated carcinoma) or combined gastrointestinal stromal tumor (GIST) before randomization.
Suspicious metastatic lesions or locally advanced unresectable disease, regardless of stage.
History of gastrointestinal perforation or fistula within 6 months before randomization. May be enrolled if perforation/fistula has been surgically treated (repaired/resected) and disease recovery/remission is confirmed by the investigator.
Active diverticulitis, intra-abdominal abscess, or gastrointestinal obstruction.