The objective of the program is to provide access to TAS-102 to patients with metastatic colorectal cancer who are refractory to or failing standard chemotherapy, are new to therapy with TAS-102 and in whom therapy with TAS-102 is clinically indicated.

This is an open-label study to provide expanded access to TAS-102 prior to its commercial availability for patients with metastatic colorectal cancer who have been previously treated with, or are not candidates for fluoropyrimidine-, irinotecan-, and oxaliplatin-based chemotherapy, an anti-vascular endothelial growth factor (VEGF) therapy, and an anti-epidermal growth factor receptor (EGFR) therapy.

Serious adverse event information (whether or not related to TAS-102) as well as reports of pregnancy, overdose, or medication error will reported. In addition, all grades of adverse drug reactions (ADRs, adverse events related to study medication) and any adverse event that results in treatment discontinuation will be recorded as study data on CRFs.

Inclusion Criteria:

1. Has provided written informed consent
2. Has adenocarcinoma of the colon or rectum
3. Has failed at least 2 prior regimens of standard chemotherapies for metastatic colorectal cancer
4. ECOG performance status of 0 or 1
5. Is able to take medications orally
6. Has adequate organ function (bone marrow, kidney and liver)
7. Women of childbearing potential must have a negative pregnancy test and must agree to adequate birth control if conception is possible. Males must agree to adequate birth control.

Exclusion Criteria:

1. Certain serious illnesses or medical condition(s)
2. Has had certain other recent treatment e.g. major surgery, anticancer therapy, extended field radiation, received investigational agent, within the specified time frames prior to study drug administration
3. Has received TAS-102
4. Has unresolved toxicity of greater than or equal to CTCAE Grade 2 attributed to any prior therapies
5. Is a pregnant or lactating female