This study is an open-label, non-randomized trial design, including a dose escalation phase and a dose expansion phase, to evaluate the safety, tolerability and preliminary anti-tumor activity of SYS6010 in combination with SYH2051 in patients with advanced gastrointestinal tumors.

Inclusion Criteria:

• Age ≥18 years.
• Patients with unresectable or metastatic colorectal cancer or other gastrointestinal tumors confirmed by histology or pathology, who have failed at least first-line standard therapy or for whom standard treatment is not applicable.
• Provide tumor tissue samples for immunohistochemical EGFR expression testing, with EGFR expression positive as confirmed by the central laboratory.
• At least one measurable lesion confirmed according to RECIST v 1.1 criteria.
• ECOG performance status score of 0-1.
• Expected survival of ≥3 months.
• Major organ functions must meet relevant laboratory criteria for blood counts, renal function, liver function, and coagulation within 7 days prior to treatment.
• Subjects agree to use effective contraception during the study and for 6 months after the last dose, with women being non-lactating and men refraining from sperm donation. Women of childbearing potential must have a negative serum pregnancy test within 7 days prior to the first administration of the study drug.
• Willing to participate in the study, understand the study procedures, and sign a written informed consent form.

Exclusion Criteria:

• Previously treated with antibody-drug conjugates (ADC) containing topoisomerase I inhibitors.
• Failure to meet the required washout period for prior medications or treatments as specified in the protocol..
• Has other primary malignancies within 3 years prior to the first dose of the study drugs.
• History of severe cardio-cerebrovascular disease.
• Adverse events from prior anti-tumor treatments that have not resolved to ≤ Grade 1 of CTCAE V5.0.
• Patients with active central nervous system and/or leptomeningeal metastases.
• Clinically significant pleural effusion, peritoneal effusion, or pericardial effusion requiring intervention.
• Has a history of Interstitial lung disease (ILD)/non-infectious pneumonitis that required steroids, has current ILD/non-infectious pneumonitis, or where suspected ILD/non-infectious pneumonitis cannot be ruled out by imaging at screening.
• Patients with thyroid dysfunction requiring treatment, but that well-controlled was allowed.
• Severe infections within 4 weeks prior to the first administration of the study drugs.
• Prior interruption of EGFR-targeted therapy due to skin toxicity, or skin diseases requiring oral or intravenous treatment currently.
• Known allergy to any component of SYS6010 or SYH2051, or any humanized monoclonal antibody product.
• Severe ophthalmic history (e.g., dry eye syndrome, keratitis, conjunctivitis, etc.).
• Had a history of autoimmune disease (except tuberous sclerosis), immunodeficiency (including positive HIV test), or other acquired or congenital immunodeficiency diseases, or organ transplantation.
• Active HBV, HCV infection or syphilis infection.
• Other conditions deemed by the investigator as unsuitable for participation in this clinical trial.