Modified FOLFIRINOX and Pentamidine in Advanced and Metastatic Pancreatic Cancer

The patients will undergo testing, exams, and procedures per the Protocol. On study, patients will be randomized into one of the two arms. In Arm A (up to 15 patients) will be treated with modified FOLFIRINOX every two weeks, delivered as follows: * Oxaliplatin 85mg/m2 IV over 2 hours on Day 1, followed by, * Irinotecan 150mg/m2 IV over 90 minutes on Day 1, followed by * Leucovorin 400mg/m2 IV over 2 hours on Day 1, followed by * 5FU 2400mg/m2 IV over 46-48 hours on Days 1-3 In arm B patients (up to 15), the same modified FOLFIRINOX regimen will be used, as above, plus 300 mg pentamidine will be administered IV over a one-hour infusion on Day 1 of each cycle. In both arms, patients will be treated over eight two-week cycles, and the entire treatment is expected to last approximately 4 months. After eight cycles, patients will undergo another EUS core biopsy. At the same time as the biopsy, an additional blood draw (for translational endpoints) will be done. After the biopsy, patients will continue treatment per physician's discretion for an additional 2 months (or 4 cycles) for a total of 12 cycles (or 6 months of treatment) until disease progression or appearance of unacceptable toxicity.