A Study to See if hENT1 Testing on Tumour Tissue Can Predict Response to Treatment With Gemcitabine Chemotherapy and if a Different Chemotherapy Called FOLFOX is Better Than Gemcitabine in Metastatic Pancreas Cancer

Inclusion Criteria:

* Histologically documented metastatic pancreatic adenocarcinoma not previously treated with palliative systemic therapy
* Metastatic disease based on the presence of clinically and/or radiologically documents Measurable disease base on RECIST.
* Adequate tissue (core biopsy) available for IHC testing of hENT1. This may be from primary tumour or metastatic site. Fine needle aspiration biopsies will not be allowed. Histological/cytological confirmation of tissue to ensure sufficient material is available for hENT1 analysis by the Cross Cancer Institute is required prior to starting a patient on study. Biopsies from metastatic sites must be obtained ≥ 3 months after any adjuvant chemotherapy (if applicable). If a patient has had previous surgical resection of their primary tumours, that tissue can be utilized. Tissue sufficient for preparing ≥ 10 unstained slides for central storage and testing is required.
* ECOG performance status of 0 - 1.
* Age ≥ 18 years.
* Life expectancy of at least 3 months based on discretion of treating oncologist.
* Adequate hematologic function defined by the following laboratory parameters:
* Hemoglobin ≥ 100
* Platelet count ≥ 100
* Absolute granulocyte count ≥ 1.5
* Adequate hepatic and renal function defined by the following laboratory parameters:
* AST and ALT ≤ 2.5 X upper limit of institutional normal (≤ 5 if liver metastases)
* bilirubin ≤ upper limit of institutional normal
* calculated creatinine clearance of ≥ 50 mL/min using the Cockcroft-Gault formula, if just below 50 mL/min based on this formula then GFR ≥ 50 mL/min as determined by 24 hr urine collection
* Patients who have received prior chemotherapy or radiation delivered as part of initial curative therapy (i.e. neoadjuvant or adjuvant chemotherapy administered alone and/or concurrently delivered with radiation and/or surgery) are permitted as long as that treatment was completed at least 6 months prior to study start date.
* Patients may have received prior palliative radiotherapy (unless radiation was curative therapy to pelvis or to ≥ 25% of bone marrow stores) if this radiation was ≥ 4 weeks before study entry and patients must have recovered from the toxic effects of this treatment
* Patients may have received prior surgery if this surgery was ≥ 4 weeks before study entry and patients must have recovered from the toxic effects of this treatment.
* Patients must have the ability to read, understand, and sign an informed consent and must be willing to comply with study treatment and follow-up.

Exclusion Criteria:

* Patients who have received prior palliative chemotherapy for their metastatic pancreatic adenocarcinoma.
* Radical pancreatic resections (e.g. Whipple procedure) are not allowed \< 6 months prior to randomization. Exploratory laparotomy, palliative (e.g. bypass) surgery, or other procedures (e.g. stents) are not allowed \< 14 days prior to randomization. In any of the above cases, patients must be adequately recovered and stable prior to randomization.
* Prior treatment with \> 6 cycles of traditional alkylating agent-based chemotherapy, \> 2 cycles of carboplatin-based chemotherapy, prior treatment with irinotecan or oxaliplatin chemotherapy, or concurrent treatment with other experimental drugs or anti-cancer therapy.
* Curative radiation treatment to the pelvis or radiation therapy to ≥ 25% of bone marrow stores.
* Lack of physical integrity of the upper gastrointestinal tract, malabsorption syndrome, short gut syndrome, or history of bowel obstruction due to peritoneal metastases.
* Previous or concurrent malignancies, excluding curatively treated in situ carcinoma of the cervix or non-melanoma skin cancer, unless at least 5 years have elapsed since last treatment and the patient is considered cured.
* Any serious medical condition within 6 months prior to study entry such as myocardial infarction, uncontrolled congestive heart failure, unstable angina, active cardiomyopathy, unstable ventricular arrhythmia, cerebrovascular diseases, uncontrolled hypertension, uncontrolled diabetes, uncontrolled psychiatric disorder, serious infection, active peptic ulcer disease, or other medical condition that may be aggravated by treatment.
* Known dihydropyrimidine dehydrogenase (DPD) deficiency.
* Pre-existing neuropathy ≥ grade 2 from any cause.
* Patients with unstable metastasis to the central nervous system are excluded. Patients who have treated brain metastasis and are off steroids, anticonvulsants, and have documented stability of lesions for at least 3 months may be eligible. A CT scan or MRI is NOT required to rule out brain metastases unless there is clinical suspicion of CNS involvement.
* Pregnant or lactating women; women of child bearing potential must have a negative serum pregnancy test within 7 days of trial registration. Women or men of child bearing potential must use effective contraception (defined by the treating physician) which must be documented in study CRFs.
* Any other reason the investigator considers the patient should not participate in the study.