First-line Treatment With RC48 Plus Sintilimab and S-1 in Advanced Gastric Cancer (RCTS2)

Inclusion criteria

• Aged18-75 years, gender is not limited;
• Pathologically confirmed locally advanced gastric or gastroesophageal junction adenocarcinoma that is inoperable or has distant metastasis;
• HER2-Positive (IHC3+or IHC2+/FISH+) ;
• Has at least 1 measurable lesion as determined by RECIST 1.1;
• There is no systematic treatment in the past, or the patient has received neoadjuvant/adjuvant chemotherapy, but the disease progresses or relapses more than 6 months after the end of treatment;
• Eastern Cooperative Oncology Group (ECOG) performance status of 0-1;
• Adequate organ function;
• The life expectancy is at least 3 months;

Exclusion criteria

• Allergy to any trial drug and its excipients, or serious allergy history, or contraindication of the trial drug;
• Cardiovascular and cerebrovascular events that are not well controlled;
• Has received systematic treatment with Chinese patent medicine or immunomodulatory drugs (including thymosin, interferon, interleukin, except for local use for ascites control) before the first administration within 2 weeks.
• Have a history of interstitial lung disease, non-infectious pneumonia, pulmonary fibrosis, acute lung disease, or systemic disease with poor control (including but not limited to diabetes, hypertension, etc.);
• Have a history of active immune deficiency or autoimmune diseases, including HIV positive test, or have other acquired or congenital immune deficiency diseases, or have a history of organ transplantation or autoimmune diseases;
• Severe chronic or active infection requires systemic antibacterial, antifungal or antiviral treatment, including tuberculosis infection.Have a history of active tuberculosis infection ≥ 1 year before recruitment should also be excluded, unless proved has been completed appropriate treatment;
• Brain metastasis or leptomeningeal metastasis;
• Clinically significant pleural effusion, pericardial effusion or ascites should be drained for many times within 2 weeks before the first administration of the trial drug;
• Has a second clinically detectable primary malignant tumor at the time of recruitment, or there were other malignant tumors in the past 5 years (except for fully treated skin basal cell carcinoma or cervical carcinoma in situ);
• Any major surgery was performed ≤ 28 days before the first trial drug administration;
• History of allogeneic stem cell transplantation or organ transplantation;