The purpose of this study is to determine the efficacy and safety of nanoparticle albumin-bound paclitaxel (nab-paclitaxel) plus S-1 as first-line treatment in Chinese patients with advanced pancreatic ductal adenocarcinoma (PDA).

Advanced PDA is a lethal disease with a approximately 6 months of median survival. Gemcitabine is always the only approved single agent. The recent results of the phase III trial MPACT (Metastatic Pancreatic Adenocarcinoma Clinical Trial) demonstrated an improvement in overall response rate (ORR), progression free survival (PFS) and overall survival (OS) for the combination of nab-paclitaxel plus gemcitabine compared to gemcitabine alone. Thus, the combination of nab-paclitaxel with gemcitabine became one of a standard treatment in metastatic PDA. S-1 is an oral fluoropyrimidine, and shown to be non-inferior to gemcitabine on OS for unresectable pancreatic cancer, and also demonstrated non-inferior, and even superior to gemcitabine as adjuvant chemotherapy. This single-arm study is to explore the efficacy and safety of nab-paclitaxel plus S-1 as first-line treatment in Chinese patients with local advanced or metastatic pancreatic ductal adenocarcinoma.

Inclusion Criteria:

1. Signed informed-consent form.
2. Age no less than 18 years.
3. Histologically confirmed locally advanced or metastatic pancreatic ductal adenocarcinoma, with RECIST measurable lesions.
4. Eastern Cooperative Oncology Group (ECOG) 0-1 with life expectation of no less than 12 weeks.
5. Patients must have received no previous chemotherapy or investigational therapy for the treatment of metastatic disease. Prior treatment with 5-fluorouracil or gemcitabine administered as a radiation sensitizer in the adjuvant setting is allowed, provided at least 6 months have elapsed since completion of the last dose and no lingering toxicities are present.
6. Adequate liver/bone marrow function.
7. Human Chorionic Gonadotropin (HCG) test negative for female with contraception measure until 3 months after study end.
8. Compliant, and can be followed up regularly.

Exclusion Criteria:

1. Pregnant or breast-feeding female, or not willing to take contraception measures during study.
2. Serious infection requiring antibiotics intervention during recruitment.
3. Allergic to study drug.
4. More than grade 1 neuropathy.
5. Uncontrolled brain metastasis or mental illness.
6. Congestive heart failure, uncontrolled cardiac arrhythmia, etc.
7. Other malignancy within 5 years.
8. Can't be followed up or obey protocol.
9. Ineligible by the discretion of the investigator.