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.