• Have fully understood the study and voluntarily signed the informed consent;

• Age ≥18 years old, gender unlimited;

• Advanced metastatic colorectal adenocarcinoma confirmed by histopathology;

• The patient progressed or was intolerant after receiving at least previous standard therapy containing fluorouracil, oxaliplatin, and irinotecan.

‣ Each first-line treatment must include one or more chemotherapeutic agents for a duration of ≥1 cycle;

⁃ Allow pre-adjuvant/neoadjuvant therapy. If recurrence or metastasis occurs during or within 6 months after completion of adjuvant/neoadjuvant therapy, adjuvant/neoadjuvant therapy is considered a failure of first-line chemotherapy for advanced disease;

⁃ Prior chemotherapy combined with cetuximab or bevacizumab is permitted;

• Have at least one measurable lesion (RECIST 1.1 standard);

• Eastern Cooperative Oncology Group (ECOG) physical condition 0-1 score;

• Expected survival ≥12 weeks;

• The functions of vital organs during the first 14 days of enrollment meet the following requirements (the use of any blood components and cell growth factors during the first 14 days of enrollment is not allowed) :

‣ Absolute neutrophil count ≥1.5×109/L;

⁃ Platelet ≥80×109/L;

⁃ Hemoglobin ≥8g/dL;

⁃ Total bilirubin \< 1.5 × upper limit of normal（ULN）;

⁃ Alanine aminotransferase (ALT) and Aspartate aminotransferase (AST) \< 2.5 × ULN (\< 5 × ULN in patients with liver metastasis);

⁃ Serum creatinine ≤1 × ULN;

⁃ endogenous creatinine clearance \> 50ml/min;

• Women of childbearing age or men whose partners wish to have children need to take effective contraceptive measures.