Patients Undergoing Treatment for Pancreatic Adenocarcinoma Can Mount an Effective Immune Response to Vaccinations

Abstract

Background: Immunotherapy has been proposed as a novel treatment for pancreatic cancer. However, patients with pancreatic cancer have been observed to have depressed immune responses, suggesting that immunotherapy might have limited utility in this group of patients. We sought to determine whether patients undergoing postresection or primary medical treatment for pancreatic adenocarcinoma were immunocompetent. Methods: We enrolled patients with pancreatic adenocarcinoma scheduled for postresection or primary chemotherapy and/or radiation therapy. At the initiation of therapy, the patients had an anergy panel placed and baseline blood work performed. During the first week of treatment, patients received tetanus toxoid (TT), Haemophilus influenzae and Pneumococcus vaccines. Twelve weeks after vaccine administration, IgG titers against the 3 administered vaccines were done, and lymphocyte proliferation assays in response to TT were performed. Results: Eighteen patients were originally enrolled, and 14 patients completed all elements of the trial. Anergy panel responses were obtained for 15 patients who comprised the final study group; both pre- and postvaccination data were available for 14 patients. Nine of 15 patients demonstrated at least a 10-mm induration in response to mumps or Candida antigen (60% response rate, 95% confidence interval (CI) 32–84%). Thirteen of 14 patients demonstrated a ≧3-fold increase in IgG against one or more vaccines (93% response rate, 95% CI 66–100%). Nine of 14 patients (64% response rate, 95% CI 35–87%) demonstrated at least a 3-fold rise of lymphocyte proliferation against TT. Conclusions: Patients with pancreatic cancer were capable of mounting effective cellular and humoral responses to standard vaccines. These data suggest that immunotherapy for pancreatic cancer may be feasible and merits further investigation.