⁃ Subjects voluntarily enrolled in the study and signed an informed consent form, were compliant and cooperated with follow-up visits;

⁃ Patients with metastatic colorectal adenocarcinoma confirmed by pathology or histology;

⁃ Patients with second-line metastatic colorectal adenocarcinoma who have failed prior standard first-line treatment (recurrence within 6 months of the end of adjuvant chemotherapy is considered first-line treatment failure);

⁃ Tumor tissue testing at the primary or metastatic site allows enrollment in second-line therapy regardless of whether the KRAS, NRAS, or BRAF genes are wild-type or mutant, and regardless of microsatellite status as MSS/ pMMR or MSI-H/dMMR. For MSI-H/dMMR patients, first-line treatment was similarly allowed for enrollment if immunotherapy was used in the second line;

⁃ Age: 18-75 (inclusive of 18 and 75), male or female;

⁃ ECOG score: 0-1;

⁃ Expected survival ≥ 3 months;

⁃ At least one measurable lesion (based on RECIST 1.1 criteria);

⁃ Patients must undergo UGT1A1 genetic testing;

‣ Major organs and bone marrow function were essentially normal (no blood components or cell growth factors had been used in the 14 days prior to enrollment):

• Blood count: leukocytes ≥ 3.5 x 109 /L, neutrophils ≥ 1.5 x 109 /L, platelets ≥ 100 x 109 /L, hemoglobin ≥ 90 g/L; 2)International normalized ratio (INR) ≤ 1.5 x upper limit of normal (ULN) and activated partial thromboplastin time (APTT) ≤ 1.5 x ULN; 3)Liver function: total bilirubin ≤ 1.5 x ULN; ALT/AST/ALP ≤ 2.5 x ULN in the absence of liver metastases; ALT/AST/ALP ≤ 5 x ULN in the presence of liver metastases; 4)Renal function: serum creatinine ≤ 1.5 x ULN and creatinine clearance (CCr) ≥ 60 mL/min (see Appendix); 5)Normal cardiac function with left ventricular ejection fraction (LVEF ) ≥50% by 2D cardiac ultrasound; 11. Male or female patients of childbearing potential will voluntarily use an effective method of contraception, e.g., double-barrier contraception, condoms, oral or injectable contraceptives, intrauterine devices, etc., for the duration of the study and for 6 months after the last study dose. All female patients will be considered of childbearing potential unless the female patient is naturally menopausal, has undergone artificial menopause or sterilization (e.g., hysterectomy, bilateral adnexectomy, or radiation ovarian irradiation, etc.), unless the female patient has a serum or urinalysis that shows no pregnancy within the 7 days prior to the study, and must be a non-lactating patient.