A Study to Evaluate the Efficacy and Safety of MRG003 in Patients With Advanced Gastric Cancer.

Inclusion Criteria: * \- Willing to sign the ICF and follow the requirements specified in the protocol. * Age: 18-75 years (including 18 and 75), both genders. * Expected survival time≥3 months. * Patients with histologically confirmed inoperable locally advanced or metastatic gastric adenocarcinoma. * Tumor tissue must be EGFR positive and HER2 negative. * Patients must have measurable lesions according to the Response Evaluation Criteria in Solid Tumors (RECIST v1.1). * ECOG performance score 0 or 1. * Organ functions and coagulation function must meet the basic requirements. * No severe cardiac dysfunction with left ventricular ejection fraction (LVEF) ≥ 50%. * Serum or urine pregnancy test negative within 7 days before the first dose of investigational drug. * Patients with childbearing potential must use effective contraception during the treatment and for 6 months after the last dose of treatment. Exclusion Criteria: * \- Squamous cell carcinoma, carcinoid, neuroendocrine carcinoma, undifferentiated carcinoma, or other gastric cancers,or adenocarcinoma with other pathological components that cannot be classified, or adenocarcin oma accompanied by other pathological components. * History of hypersensitivity to any component of the study drug or to other EGFR-targeting agents. * Antitumor biological therapy or immunotherapy, targeted small molecule therapy and have history of systemic chemotherapy within 4 weeks before the first administration of the investigational drug, or major surgery. Traditional Chinese medicine, Chinese patent medicine or traditional Chinese medicine formula with anti-tumor effect should not be used within 2 weeks before the first administration. * Potent CYP3A4 inhibitors or inducers are in use and cannot be discontinued. * Known active CNS metastasis. * Uncontrolled pleural effusion, pericardial effusion or recurrent ascites. * Patients with intestinal obstruction requiring treatment were excluded. * Residual toxicity reactions caused by previous anti-tumor treatment or abnormal values of laboratory tests higher than grade 1 (CTCAE v5.0). Peripheral neuropathy ≥ Grade 2 (NCICTCAE version 5.0). * Uncontrolled or poorly controlled hypertension. * Uncontrolled or poorly controlled heart disease. * Known active hepatitis B or C. * Active bacterial, viral, fungal, rickettsia, or parasitic infections that require systemic anti-infective treatment. * Known history of malignancy. * History of ophthalmologic abnormalities * History of severe skin disease * Moderate to severe dyspnea at rest caused by advanced cancer or its complications, or severe primary lung disease, oxygen saturation \< 93% in non-oxygen state, or history of any interstitial lung disease or interstitial lung disease (ILD) requiring oral or intravenous glucocorticoids or non-infectious pneumonia. * Patients with a history of active bleeding, coagulopathy, or receiving coumarin anticoagulation therapy. * History of pulmonary embolism or deep vein thrombosis within 6 months before the first administration of the investigational drug. * Patients with a history of active bleeding, coagulopathy, or receiving coumarin anticoagulation therapy. Decompensated cirrhosis of Child-Pugh class B, C * Complicated with severe, uncontrolled infection or known human immunodeficiency virus (HIV) infection, or diagnosed as acquired immunodeficiency syndrome (AIDS); or uncontrolled autoimmune disease; or history of allogeneic tissue/organ transplantation, stem cell or bone marrow transplantation, or solid organ transplantation. * Vaccination of live virus vaccine within 30 days before the first administration of the study drug. Inactivated seasonal influenza vaccine or approved COVID-19 vaccine is allowed. * Uncontrolled intercurrent illness * Patients requiring parenteral nutrition within 4 weeks * Women who are lactating or pregnant. * Other conditions that in the clinical judgement of the investigator make the patient not suitable for participation in this study.