Ipilimumab and Gemcitabine Hydrochloride in Treating Patients With Stage III-IV or Recurrent Pancreatic Cancer That Cannot Be Removed by Surgery

OUTLINE: This is a dose-escalation study of ipilimumab. INDUCTION: Patients receive ipilimumab intravenously (IV) over 90 minutes in weeks 1, 4, 7, and 10, and gemcitabine hydrochloride IV over 30 minutes in weeks 1-7 and 9-11. MAINTENANCE: Beginning in week 22, patients receive ipilimumab IV over 90 minutes once every 12 weeks and gemcitabine hydrochloride IV over 30 minutes once weekly for 3 weeks. Courses repeat every 28 days in the absence of disease progression or unacceptable toxicity. Treatment modifications may apply according to response. After completion of study treatment, patients are followed up monthly for 6 months and then every 3 months.