Cancer vaccine therapy using dendritic cells and cancer antigen peptide against patients with advanced gastrointerstinal cancer

Background: We conducted a clinical study using dendritic cells (DCs) and MAGE peptides for patients with advanced gastrointestinal cancer. The patients had already been treated with standard therapy such as surgery, chemotherapy and radiation therapy. They also had a measurable disease as revealed by CT. Considering these situations, the patients who joined the study had a poor systemic condition. Here we report the results of our cancer vaccine therapy, and consider the method for evaluating the efficacy of cancer vaccine. Patients and results: We performed vaccine therapy on 24 patients; 6 with esophageal cancer, 10 with gastric cancer, 6 with colorectal cancer, 1 with pancreatic cancer, and 1 with gall bladder cancer. No patients showed more than grade 3 adverse events in relation to the vaccine therapy. Eleven of 24 patients showed decrease of tumor marker. No patients exhibited effective results that were based on RECIST (PR and CR). Three evidenced MR, 1 long NC, and 1 a combination of MR and PD. The other 10 patients showed PD. Conclusion: No patients showed PR or CR by this vaccine therapy alone. The kinetics of tumor marker, CTL response, DTH, and Th1/Th2 balance seems to be related with clinical status to some degree, however none were critical. Based on the evaluation by RECIST, this vaccine therapy was considered "not effective". We suggest that a new evaluation method is required for cancer vaccine therapy that may contribute to improvement of PS of patients, and tumor dormancy therapy.