The primary objective of this study is to evaluate the pharmacokinetics of TAS-102 after single and multiple dose in Chinese patients with solid tumor.

This is an open-label, non-randomized, single group Phase 1 study of TAS-102, evaluating the pharmacokinetics, safety, and antitumor activity. Blood sampling will be performed during the first cycle (Day1 and Day 12) of therapy in all consenting patients.

Inclusion Criteria:

• 1. Has provided written informed consent prior to performance of any study procedure.
• 2. Has definitive histologically or cytologically confirmed advanced or metastatic solid tumor.
• 3. Is able to take medications orally.
• 4. Has adequate organ function (bone marrow, kidney and liver).
• 5. Has Eastern Cooperative Group (ECOG) performance status of 0 or 1.

Exclusion Criteria:

• 1. Has received TAS-102.
• 2. Has suffered serious complications.
• 3. Has unresolved toxicity of greater than or equal to CTCAE Grade 2 attributed to any prior therapies.
• 4. Has had prior gastrectomy.
• 5. Is a pregnant or lactating female or male who refused using birth control during the clinical trial period and within 6 months after discontinuation of study treatment.

15 weeks