This is a prospective phase II, single arm clinical trial conducted in Queen Mary Hospital (Hong Kong) assessing the efficacy and safety of TAS-102 in advanced or metastatic pancreatic cancer patients.

All the patients must be registered with the Investigator(s) prior to initiation of treatment. The registration desk will confirm all eligibility criteria and obtain essential information (including patient number).

Inclusion Criteria:

1. Histological or cytological confirmed advanced or metastatic pancreatic cancer

2. Measurable disease according to the RECIST criteria (version 1.1) for the evaluation of measurable disease

3. Documented progression after one or more lines of systemic chemotherapy

   1. For the treatment of advanced or metastatic disease
   2. Within 6 months after completion of neo-adjuvant therapy or adjuvant therapy

4. Age ≥ 18 years

5. Eastern Cooperative Oncology Group (ECOG) performance 0-1

6. Written informed consent obtained for clinical trial participation and providing archival tumor tissue, if available

7. Females of childbearing potential or non-sterilized male who are sexually active must use a highly effective method of contraception

8. Females of childbearing potential must have negative serum or urine pregnancy test

9. Have life expectancy ≥ 3 months

10. Adequate organ function as defined as:

    1. Hemoglobin value of ≥9.0 g/dL.
    2. Absolute neutrophil count of ≥1,500/mm3 (IU: ≥1.5 × 10^9/L).
    3. Platelet count ≥100,000/mm3 (IU: ≥100 × 10^9/L).
    4. Total serum bilirubin of ≤1.5 mg/dL (except for Grade 1 hyperbilirubinemia due solely to a medical diagnosis of Gilbert's syndrome).
    5. Aspartate aminotransferase (AST/SGOT) and alanine aminotransferase (ALT/SGPT) ≤3.0 × upper limit of normal (ULN); if liver function abnormalities are due to underlying liver metastasis, AST and ALT ≤5 × ULN.
    6. Serum creatinine of ≤1.5 mg/dL

Exclusion Criteria:

1. Has disease that is suitable for local therapy administrated with curative intent

2. Has a serious illness or medical condition(s) including, but not limited to the following:

   1. Other concurrently active malignancies excluding malignancies that are disease free for more than 5 years or carcinoma-in-situ deemed cured by adequate treatment.
   2. Known brain metastasis or leptomeningeal metastasis.
   3. Active infection (i.e. body temperature ≥38°C due to infection).
   4. Ascites, pleural effusion or pericardial fluid requiring drainage in last 4 weeks.
   5. Intestinal obstruction, pulmonary fibrosis, renal failure, liver failure, or cerebrovascular disorder.
   6. Uncontrolled diabetes.
   7. Myocardial infarction within the last 12 months, severe/unstable angina, symptomatic congestive heart failure New York Heart Association (NYHA) class III or IV
   8. Gastrointestinal hemorrhage.
   9. Known human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (AIDS)-related illness, or hepatitis B or C.
   10. Patients with autoimmune disorders or history of organ transplantation who require immunosuppressive therapy.
   11. Psychiatric disease that may increase the risk associated with study participation or study drug administration, or may interfere with the interpretation of study results.

3. Has had treatment with any of the following within the specified time frame prior to study drug administration:

   1. Major surgery within prior 4 weeks.
   2. Any systemic therapy within prior 2 weeks.
   3. Any radiation within prior 2 weeks.
   4. Any investigational agent received within prior 4 weeks.

4. Untreated active hepatitis B or hepatitis C infections.

5. Has received TAS-102.

6. Has unresolved toxicity of greater than or equal to CTCAE Grade 2 attributed to any prior therapies (excluding anemia, alopecia, skin pigmentation and platinum-induced neurotoxicity).

7. Is a pregnant or lactating female.

8. Is inappropriate for entry into this study in the judgment of the Investigator.