- Arm C: Patients receive GVAX pancreatic cancer vaccine ID on day 1 and low-dose oral cyclophosphamide twice daily on days 1-7. Patients undergo pancreaticoduodenectomy on day 15. Approximately 6-10 weeks after surgery, patients receive the vaccine on day 1 and low-dose oral cyclophosphamide twice daily on days 1-7 and 15-21. Beginning approximately 1 month after vaccination, patients receive standard adjuvant chemoradiotherapy comprising gemcitabine, fluorouracil or capecitabine, and radiotherapy over 26-28 weeks. Beginning approximately 4-8 weeks after the completion of chemoradiotherapy, patients receive the vaccine on day 1 and low-dose oral cyclophosphamide twice daily on days 1-7 and 15-21. Treatment with the vaccine and cyclophosphamide repeats every 28 days for 4 courses.