Phase Ib study of ipilimumab alone or in combination with allogeneic pancreatic tumor cells transfected with a GM-CSF gene (vaccine) in pancreatic cancer.

211 Background: Ipilimumab (IPI) at 3mg/kg has been tested in pancreatic ductal adenocarcinoma (PDA) with a low but detectable response rate. This supports a role for immunotherapy in PDA. Melanoma (MEL) studies demonstrate a dose-response relationship with IPI. Preclinical studies show synergy between anti-CTLA-4 antibodies and GM-CSF cell-based vaccines. This study evaluated IPI 10mg/kg alone (Arm 1) versus IPI 10mg/kg + vaccine (Arm 2) in PDA. Methods: 30 subjects with previously treated, locally advanced or metastatic PDA were randomized (1:1) to Arm 1 or 2. Induction treatments were administered every 3 weeks (wk) X 4 doses. Subjects with stable disease (SD) or better between wk 14 and 22 were eligible for maintenance doses every 12 wks. Activity was assessed by response and overall survival (OS). IFN-g Elispots and ELISAs were used to detect induction of mesothelin-specific T cells and galectin-3 antibodies (Abs), respectively. Results: Baseline characteristics were similar (87% metastatic, 100% gem...