RC48 Plus AK105 and Cisplatin in Advanced Gastric Cancer

Inclusion Criteria: * Age ≥18 years old, ≤75 years old, regardless gender * Pathologically confirmed gastric adenocarcinoma, Her2 immunohistochemical examination of 2+ or 3+ * ECOG PS scores 0-1 * Stage IV according to AJCC 8.0 and no systemic therapy previously * Expected lifespan ≥ 3 months * Adequate organ function * At least one measurable lesion according to RECIST 1.1 * Asymptomatic intracranial metastasis * No history of other malignancies * Women of childbearing age must have a negative blood pregnancy test within 7 days, and subjects of childbearing age must use appropriate contraception during the trial and for 6 months after the trial * Agreed to participate in this clinical study and signed the Informed Consent Exclusion Criteria: * Currently participating in an interventional clinical investigational treatment, or have received other investigational drugs or treatment with an investigational device within 4 weeks prior to the first dose * Received anti-PD-1, anti-PD-L1, anti-CTLA-4, and other checkpoint inhibitor * Received traditional Chinese medicines or immunomodulatory drugs with anti-gastric cancer indications within 2 weeks before the first administration * Active autoimmune diseases or immunodeficiency diseases * Allergy to any test drug and its excipients, or a history of severe allergy, or contraindication to the test drug * Severe mental disorder * Receiving systemic corticosteroids within 7 days prior to the first dose of the study * Clinically apparent cardiovascular and cerebrovascular disease * Others investigators evaluated not meet the inclusion criteria