SOX Sequential S-1 in Advanced Biliary Tract Carcinoma（BTC）and Pancreatic Cancer

Inclusion Criteria:

* Written Informed consent
* Male or female patients \>=18 years old
* Histologically or cytologically confirmed diagnosis of adenocarcinoma
* No previous treatment is allowed including chemotherapy, radiotherapy,immunotherapy or others.
* In case the patient received adjuvant therapy before, enrollment is allowed if the adjuvant therapy does not contain L-OHP or S-1 and at the same time, the last day of chemotherapy is ≥180 days before screening.
* Target lesion more than 1cm in diameter by enhanced CT or MRI 21 days before enrollment
* The laboratory parameter meets the following criteria 7 days before enrollment

  * Hemoglobin ≥90g/L
  * Absolute neutrophil count≥1.5×10\^9/L, platelets 100×10\^9/L；
  * ALT and AST≤2.5 ULN(in case of the patients with liver metastasis,ALT and AST≤5.0 ULN)
  * ALP ≤2.5 ULN (in case of the patients with liver metastasis,≤5.0 ULN)
  * Total Serum bilirubin ≤1.5 ULN
  * Serum creatinine ≤1.0 ULN
  * serum albumin(ALB)≥30g/L；
* can tolerate oral drug administration；
* KPS ≥70
* Estimated survival ≥90 days
* Women of childbearing potential must have a negative serum or urine pregnancy test within 7 days of enrollment and must be willing to use adequate methods of contraception during the study and for 30 days after last study durg administration.

Exclusion Criteria:

* Known sensitivity to 5-HT3 antagonist and hypersensitivity to the other treatment agents including irinotecan, cisplatin and octreotide lar
* Any participation in trials simultaneously or 4 weeks before screening.
* 15 days prior to enrollment, received a blood transfusion, blood products and hematopoietic growth factors such as G-CSF.
* Undergone major surgery ≤ 4 weeks prior to starting study drug or who have not recovered from side effects of such surgery.
* Uncontrolled severe diarrhea
* Uncontrolled active infection (fever ≥38 degrees due to infection)
* S-1 oral drug administration difficulty due to difficulty swallowing, complete or incomplete digestive tract obstruction, gastrointestinal active bleeding, perforation;
* severe hepatopathy including active hepatitis and hepatic cirrhosis, renal dysfunction, severe pulmonary diseases including interstitial pneumonia, pulmonary fibrosis and severe pulmonary emphysema, uncontrolled diabetes, hypertension and other chronic systematic diseases.
* Chronic treatment with steroids.(In case of the patients with short-term use of steroids, the enrollment is permitted if the administration is stopped 2 weeks before screening.)
* confirmed or suspected CNS metastasis
* the history of peripheral nervous system impairment, obvious mental disorder or CNS impairment
* clinically significant heart disease, including congestive heart failure, symptomatic coronal heart disease, arrythmia uncontrolled by medication and acute myocardial infarction or cardiac insufficiency within 6 months before screening
* Drainage of pleural effusion, peritoneal effusion and pericardial effusion
* pregnant women or women in lactation period
* Fertile male or women of child-bearing potential refuse to take highly effective methods of birth control
* Incidence of other second primary malignant tumors within 5 years, except for cured basal cell carcinoma and cervical carcinoma in situ.
* patients of legal incapacity or who have the potential of influence the whole trial due to medical or ethic reasons.
* Other patients who are not eligible to the trial under investigators' discretion