The purpose of this study is to compare 2nd line XELIRI/FOLFIRI + simvastatin vs XELIRI/FOLFIRI + placebo.

To compare progression free survival of the standard second line chemotherapy (FOLFIRI, XELIRI) plus simvastatin in metastatic colorectal cancer patients. This trial is a placebo-controlled study.

Inclusion Criteria:

1. Histologically documented colorectal adenocarcinoma (previously failed to oxaliplatin)
2. Age over 19 years old
3. Performance status (ECOG scale): 0-2
4. Measurable or evaluable disease
5. Adequate organ functions
6. Life expectancy ≥ 3 months
7. No history of statin treatment within the last 12 months
8. Patients should sign a written informed consent before study entry.

Exclusion Criteria:

1. Tumor type other than adenocarcinoma
2. Second primary malignancy (except in situ carcinoma of the cervix or adequately treated basal cell carcinoma of the skin, papillary thyroid carcinoma or prior malignancy treated more than 5 years ago without recurrence)
3. Adjuvant or neo-adjuvant treatment for non-metastatic (M0) disease is allowed if completed at least 6 months prior to initiation of study treatment.
4. Prior radiotherapy is permitted if it was not administered to target lesions selected for this study, unless progression of the selected target lesions within the radiation portal is documented, and provided it has been completed at least 4 weeks before randomization.