Biological Effect of Warfarin on Pancreatic Cancer

Inclusion Criteria:

* Pathologically-confirmed, localized or metastatic adenocarcinoma of the pancreas. Diagnostic biopsy must be obtained at the study institution prior to enrollment. Pathology material must be available for review.
* Patient must have measurable disease per RECIST criteria
* Started most recent systemic therapy regimen within 15 days of enrollment (any line of therapy is allowed).
* Ability to tolerate, swallow and absorb oral medications.
* Ability to understand and the willingness to sign a written informed consent.
* Age \> 18 years
* Negative blood pregnancy test within seven days of study entry for WOCBP
* A female of child-bearing potential is any woman (regardless of sexual orientation, having undergone a tubal ligation, or remaining celibate by choice) who meets the following criteria:

  * Has not undergone a hysterectomy or bilateral oophorectomy; or
  * Has not been naturally postmenopausal for at least 12 consecutive months (i.e., has had menses at any time in the preceding 12 consecutive months).

Exclusion Criteria:

* Active radiation therapy, or planned radiation therapy during study period
* Subjects may not be receiving any other investigational agents.
* Pregnant, nursing or women of childbearing potential and men who are sexually active and not willing/able to use medically acceptable forms of contraception; this exclusion is necessary because the treatment involved in this study may be potentially teratogenic.
* Underlying condition which may increase the risk of complications from warfarin therapy. These can include:

Known major bleeding diathesis:

* Coagulopathy
* Significant GI bleed within 6 months,
* Clinically significant hematuria or hemoptysis,
* Thrombolytic therapy within one month of study entry,
* Active peptic ulcer disease with bleeding. - Significant infection or other coexistent medical condition that would preclude protocol therapy including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements