Study of Gemcitabine Plus Nab-paclitaxel Versus S1 Plus Nab-paclitaxel in Metastatic Adenocarcinoma of the Pancreas

Inclusion Criteria: * Histological or cytological confirmation of pancreatic adenocarcinoma * Distant metastatic or unresctable locally advanced diseases * CTScan (or MRI if scanner contraindicated) completed within 3 weeks of the start of treatment * At least one lesion measurable by RECIST v1.1 criteria * Life expectancy\> 3 months * No previous chemotherapy (adjuvant chemotherapy with gemcitabine authorised if administered more than 6 months prior to inclusion) * No previous radiotherapy (unless at least one measurable target lesion outside the irradiation zone) * Pain must be monitored before inclusion * 18 years \< age \< 70 * Performance status: 0-1 * ANC ≥ 1500/mm3, platelets ≥ 100 000/mm3, haemoglobin ≥ 9 g/dL * ASAT (SGOT), ALAT (SGPT) ≤ 2.5 x ULN or ≤ 5 x ULN if liver metastases found * Bilirubin ≤ 1.5 x ULN (patients drained by retrograde technique are includable), * creatinine \< 120 μmol/L, or MDRD creatinine clearance \> 60 mL/min * Patient information and signature of informed consent Exclusion Criteria: * Concurrent other effective treatment (including radiotherapy) * Resectable patients * Allergy history to other drugs in the same class patients with pregnancy or lactation * Known severe internal medical diseases * Abnormal heart function or relevant history of myocardial infarction and severe arrhythmia * Immunocompromised patients, such as HIV positive * Uncontrollable mental illness * Other conditions the researchers considered ineligible for the study