This is an open-label, single centre, single-arm phase II study which aims to assess the efficacy and tolerability of triplet combination of capecitabine, oxaliplatin and irinotecan (Xeloxiri regimen) in treating patients with refractory metastatic colorectal cancer. Clinical data from patients diagnosed with colorectal cancer will be collected and analyzed in this study. The patients' data will be collected and maintained in the Division of medical oncology of the Department of Medicine, Queen Mary Hospital.

Inclusion Criteria:

• Adults ≥ 18 years of age, male or female.
• Histopathologically or cytologically confirmed adenocarcinoma.
• Failed ≥ 2 lines of standard therapy which must include a fluoropyrimidine, oxaliplatin and/or irinotecan, administered either as monotherapy or doublets.
• ECOG performance status 0 to 2.
• Adequate bone marrow reserve.
• Absolute neutrophil count > 1 × 109/L.
• Total bilirubin < 3 × the upper limit of the normal range.
• Life expectancy ≥ 12 weeks.
• Signed written informed consent form.

Exclusion Criteria:

• Prior malignant disease other than colorectal cancer within 5 years of study entry.
• Patients suitable for surgical or locoregional therapies.
• Patients unable to swallow oral medications.
• Any evidence of brain metastasis (unless the patient is >6 months from definitive therapy, has a negative imaging study within 4 weeks of study entry and is clinically stable with respect to the tumor at the time of study entry).
• Active clinically serious infections (> grade 2 NCI / CTC Adverse Event version 3.0).
• History of allergy to platinum compounds.
• Patients who have chronic inflammatory bowel disease and/or bowel obstruction.
• Patients who have severe bone marrow failure.
• Patients undergoing renal dialysis.
• History of HIV infection.
• Seizure disorder requiring medication (such as steroids or anti-epileptics).
• Women who are pregnant or breast-feeding, or women of child-bearing potential who are unable or unwilling to practice a highly effective means of contraception.
• Substance abuse, medical, psychological or social conditions that may interfere with the patient's participation in the study or evaluation of study results.