Carcinoembryonic Antigen-loaded Dendritic Cells in Advanced Colorectal Cancer Patients

Dendritic cells (DCs) are the professional antigen-presenting cells of the immune system. As such they are currently used in clinical vaccination protocols in cancer patients. We evaluate the ability of mature DCs pulsed with carcinoembryonic antigen (CEA)-peptide (arm A) or electroporated with CEA-mRNA (arm B) to induce CEA-specific T cell responses in patients with resectable liver metastases from colorectal cancer. To evaluate immune responses, CEA-specific T cell reactivity is monitored in peripheral blood, resected abdominal lymph nodes, tumor tissue and biopsies of vaccination sites and post-treatment DTH skin tests. Patients are vaccinated intradermally and intravenously with CEA-peptide pulsed mature DCs three times prior to resection of liver metastases. In 2007 a side-study has been added (arm C), in which patients with stage III or high-risk stage II colorectal cancer that are amenable for standard adjuvant oxaliplatin/capecitabine therapy are vaccinated with CEApeptide-pulsed DCs. Also in this group, safety and immune responses in peripheral blood and the DTH-skin test are the primary endpoints. Results are compared with the results obtained in arm A.