Abstract 5378: Phase I trial of EUS-guided intratumoral vaccination with recombinant Panvac-F and systemic Panvac-V in patients with locally advanced pancreatic cancer

Abstract

Abstract Preclinical studies in our laboratory were the first to demonstrate the superiority of intratumoral poxvirus vaccines in overcoming immune escape and effectively treating murine solid tumor models. Murine models of bladder and orthotopic mammary tumor demonstrated anergy to systemic immunization using antigen encoding vaccinia recombinants while responding to immunization into the tumor microenvironment. We present here the translation of these findings to a Phase I trial in six patients with locally advanced inoperable adenocarcinoma of the pancreas (NCT00669734). The first dose cohort of patients were treated using a combination of EUS-guided intrapancreatic tumor injection of recombinant Panvac-F (Fowlpox encoding MUC-1, CEA, TRICOM, 108 PFU) in addition to systemic Panvac-V (vaccinia, 2 X 108 PFU) and Panvac-F (109 PFU) boosts (accompanied by subcutaneous rH-GM-CSF, 100 mcg X 4 days). Patients received a total of 2 intrapancreatic injections of Panvac-F (2 weeks apart) with systemic Panvac-V and Panvac-F boosts given with GMCSF extending to day 71 (total of 2 intrapancreatic Panvac-F, 1 sc Panvac-V, 4 sc Panvac-F). Patients were allowed to transition to standard care at day 35. Patients were evaluated for toxicity, tumor progression, and serum CA 19-9 and CEA levels. Two of six patients were removed from study after approximately two weeks due to rapid disease progression and died one and six months after trial initiation. Of the remaining four, one had received prior treatment with gemcitabine followed by capecitabine and radiation and received no further treatment after vaccination; three received post-vaccination standard treatment with gemcitabine. Of the 4 patients with followup of greater than 6 mos, all have stable disease with no progression to metastasis (19 mos, 17 mos, 16 mos, 13 mos). One pt had a DLT (pancreatitis) that resolved allowing completion of protocol therapy. Results demonstrate that the “first in human” intrapancreatic administration of recombinant poxvirus was well tolerated with the complete regimen suggesting an encouraging period of stable disease. The trial is currently accruing patients at intrapancreatic dose level 2 (109 PFU). This study is supported by the NCI Cancer Therapeutics Evaluation Program (CTEP) and by NCI U01-CA07031 and P30-CA72720. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5378. doi:1538-7445.AM2012-5378