Inclusion Criteria:
(1) Patients with advanced metastatic salivary gland ductal carcinoma diagnosed histopathologically at the primary site or metastasis; (2) Original paraffin-embedded tumor tissue stained for HER2 at diagnosis, either HER2 1+/HER2 2+/HER2 3+, previous test results (confirmed by the investigator) or test results from the study center are acceptable; (3) ECOG physical status 0 or 1 within 3 days prior to the first dose of study treatment; (4) 18 years of age or older - upper limit; (5) Life expectancy greater than 3 months according to RECIST 1.1 criteria; (6) At least one measurable lesion; and (7) a score of 0 or 1 for ECOG physical status within 3 days prior to the first dose of study treatment. status 0 or 1 within 3 days prior to the first dose of study treatment; ④ 18 years of age or older - no upper limit; ⑤ life expectancy greater than 3 months; ⑥ at least one measurable lesion according to RECIST 1.1 criteria;(7) Female subjects should be surgically sterilized, post-menopausal, or agree to use at least one medically approved contraceptive (e.g., IUD, pill, or condom) during and for 6 months after the study treatment period, and must have a negative blood pregnancy test within 7 days prior to study entry and must be non-lactating. Male subjects should agree to use at least one medically approved contraceptive measure during the study treatment period and for 6 months after the end of the study treatment period; ⑧ Patients must have adequate liver, kidney, bone marrow, heart and lung organ function: bone marrow function: (1) hemoglobin ≥ 90 g/L; (2) absolute neutrophil count ≥ 1.5 × 109/L; (3) platelets ≥ 100 × 109/L Liver function (based on the normal value of the clinical trial center): (1) without liver metastases, serum total bilirubin ≤ 1.5 times ULN; with liver metastases, serum total bilirubin ≤ 3 times ULN (2) without liver metastases, ALT and AST are ≤ 3 times ULN, with liver metastases, ALT and AST are ≤ 5 times ULN Kidney function (based on the normal value of the clinical trial center): (1) blood creatinine ≤ 1.5 times ULN, or 1.5 times ULN, or Cockcroft-Gault formula calculated creatinine clearance (CrCl) ≥ 60 mL/min, or measured 24-hour urine CrCl ≥ 60 mL/min; cardiac function: (1) New York Heart Association (NYHA) classification \<3 (2) left ventricular ejection fraction ≥ 50%
Exclusion Criteria:
(i) treatment with an investigational drug or other antibody-coupled drug targeting HER2 at the start of the study drug; (ii) major surgery within 4 weeks prior to the start of the study drug and incomplete recovery; (iii) live vaccination within 4 weeks prior to the start of the study drug or any vaccine planned during the study period (except novel coronavirus vaccine);(iv) an arterial/venous thrombotic event such as cerebrovascular accident (including temporary ischemic attack), deep vein thrombosis, or pulmonary embolism within 6 months prior to study drug administration; (v) major cardiovascular disease (NYHA class 3 or 4 heart failure, second degree or greater heart block, myocardial infarction within the past 12 months, unstable arrhythmia or unstable angina, cerebral infarction within 6 months, etc.); (vi) ongoing unstable controlled systemic disease, including diabetes, hypertension, pulmonary fibrosis, acute lung disease, interstitial lung disease, cirrhosis, etc;(7) Active infection requiring systemic therapy; (8) History of active tuberculosis; (9) Positive human immunodeficiency virus (HIV) test result; (10) Positive hepatitis B surface antigen (HBsAg) with an HBV DNA copy number greater than the upper limit of normal values in the laboratory department of the study center; or (11) Positive hepatitis C virus (HCV) antibody with an HCV RNA copy number greater than the upper limit of normal values in the laboratory department of the study center; or (12) Positive hepatitis C virus (HCV) antibody with an HCV RNA copy number greater than the upper limit of normal values in the laboratory department of the study center. ⑪Conditions that, in the opinion of the investigator, may affect the safety or compliance with the study drug therapy, including but not limited to large pleural/peritoneal/pericardial effusions, uncorrectable pleural/peritoneal/pericardial effusions, psychiatric disorders, etc. ⑪Known hypersensitivity or delayed hypersensitivity to certain components of the recombinant humanized anti-HER2 monoclonal antibody-MMAE coupling agent vedicizumab (Edisil, RC48) for injection or similar drugs Hypersensitivity or delayed hypersensitivity reactions; ⑬Women who are pregnant or breastfeeding or women/men who are planning to have children
