• Subjects voluntarily enrolled in the study, signed the informed consent and had good compliance
• Age: 18-75 years old (including boundaries at the time of signing the informed consent)
• Eastern Cooperative Oncology Group (ECOG) score: 0-1
• Expected survival of more than 3 months
• Unresectable locally advanced or metastatic colorectal cancer diagnosed by histological/cytological pathology
• Disease progression or intolerable after prior treatment with oxaliplatin, fluorouracil-based and irinotecan and treated with cetuximab or bevacizumab
• Patients with genetic testing showing wild-type for both rat sarcoma (RAS) and B-type rapid response protein kinase (BRAF)
• Presence of at least 1 measurable lesion according to RECIST 1.1 criteria
• Laboratory tests meet the criteria
• Female subjects of childbearing potential must agree to use contraception (e.g., Intrauterine Device (IUD), birth control pills, or condoms) for the duration of the study and for 6 months after the end of the study; must have a negative serum pregnancy/urine pregnancy test within 7 days prior to study entry and must not be breastfeeding; male subjects must agree to use contraception for the duration of the study and for 6 months after the end of the study

• Patients who have had previous confirmation of microsatellite high instability/mismatch repair defects (MSI-H/dMMR) by immunohistochemistry (IHC), next-generation sequencing (NGS) or polymerase chain reaction (PCR)
• Presence of a disease that interferes with intravenous administration, intravenous blood collection, or multiple factors that interfere with oral administration of medications (e.g., inability to swallow, chronic diarrhoea and intestinal obstruction)
• Active inflammatory bowel disease (ulcerative colitis, Crohn's disease) within 28 days prior to first dose
• The presence or current concurrent presence of other malignancies within 2 years prior to the first dose
• Unresolved toxic reactions above Common Terminology Criteria for Adverse Events (CTCAE) Grade 1 due to any prior therapy, excluding alopecia, fatigue and peripheral neuropathy
• Major surgical treatment, incisional biopsy or significant traumatic injury within 28 days prior to first dose
• The presence of a long-standing unhealed wound or fracture
• Cerebrovascular accident (including temporary ischaemic attack, cerebral haemorrhage, cerebral infarction), deep vein thrombosis and pulmonary embolism within 6 months prior to the first dose
• Have a history of psychotropic substance abuse and are unable to quit or have a mental disorder
• Subjects with any severe and/or uncontrolled medical condition, including:

• Unsatisfactory control of blood pressure (systolic blood pressure 63 160 mmHg or diastolic blood pressure 63 100 mmHg, at least 2 measurements taken at intervals of more than 24h)
• Myocardial infarction, unstable angina pectoris, stable angina pectoris 63 Grade 2, heart failure 63 Grade 2 (New York Heart Association (NYHA) classification), arrhythmia 63 Grade 2
• Active or uncontrolled severe bacterial, viral, or systemic fungal infection (63 CTC AE grade 2 infection) within 28 days prior to first dose; patients with active tuberculosis within 1 year prior to enrolment
• Active viral hepatitis with poor control. Subjects will be screened if they meet the following requirements: Hepatitis B surface antigen (HBsAg) positive subjects with Hepatitis B virus (HBV) DNA quantification <2000 IU/ml (or 1*10 4 copy/ml) or at least 1 week of anti-HBV treatment with a 10-fold (1 log) or greater reduction in viral index prior to study entry. Subject is willing to remain on anti-HBV therapy for the entire duration of the study; HCV-infected patients (HCV Ab or HCV RNA positive) who are judged to be stable by the investigator or who are on antiviral therapy at the time of enrolment and who continue to receive approved antiviral therapy during the study
• Subjects with a history of (non-infectious) interstitial lung disease requiring systemic steroid therapy, or current interstitial lung disease/interstitial pneumonia; or subjects with Screening Imaging suggestive of suspected interstitial lung disease/interstitial pneumonia that cannot be ruled out
• History of immunodeficiency, including being human immunodeficiency virus (HIV) positive or having other acquired, congenital immunodeficiency diseases
• Poorly controlled diabetes mellitus (fasting blood glucose (FBG) > 10 mmol/L); and
• Active syphilis infection

• Known tumour-associated spinal cord compression, cancerous meningitis, with symptoms of brain metastases, or symptoms controlled for less than 4 weeks
• Imaging suggestive of tumour invasion of large blood vessels or, in the judgement of the investigator, there is a high probability of tumour rupture or invasion of vital blood vessels during the study period leading to fatal haemorrhage
• Failure to control a plasma (thoracic, abdominal, or pericardial) effusion that requires repeated drainage
• Local radiotherapy within 2 weeks or >30% bone marrow irradiation radiotherapy for bone metastases within 4 weeks prior to first dose
• Chemotherapy, targeted therapy, immunotherapy, or other antineoplastic agents within 4 weeks prior to the first dose, or who are still on drug 5.

treatment, or subjects who are still within 5 half-lives of the drug (whichever occurs first)

• Prior use of epidermal growth factor receptor/c-mesenchymal epidermal transforming factor (EGFR/c-Met) dual-antibody drugs
• Received treatment with a proprietary Chinese medicine with an anti-tumour indication as specified in the National Drug
• Administration (NMPA) approved drug insert within 1 week prior to study treatment
• History of live attenuated vaccination within 2 weeks prior to the first dose or planned live attenuated vaccination during the study period