Feasibility Study of Adoptive Immunotherapy for Metastatic Lung Tumors Using Peptide-pulsed Dendritic Cell-activated Killer (PDAK) Cells

Abstract

We have established a novel culture system to generate effector lymphocytes designated as peptide-pulsed dendritic cell-activated killer (PDAK) cells using cultured dendritic cells (DCs), synthetic peptide, peripheral blood lymphocytes, and interleukin-2 plus immobilized anti-CD3 antibody. A feasibility study of an adoptive immunotherapy trial using PDAK cells was conducted on HLA-A2 and HLA-A24 cancer patients with antigen-positive lung metastasis that was defined by serological analysis or PCR analysis. Eleven patients with lung metastasis participated in the study: 6 with colorectal cancer, 2 with pancreatic cancer, 1 each with breast and lung cancer, and 1 with melanoma. The patients received either Muc-1, CEA, gp100, Her-2 or SART-3-PDAK cells generated in vitro, intravenously in combination with 350,000 U IL-2 weekly for 9 weeks, together with a planned dose-escalation schedule of three transfers each of 1x10⁷, 3x10⁷ and 1x10⁸ PDAK cells/kg for 6 patients, and with a uniform dose of 3x10⁷ PDAK cells/kg for the remaining 5 patients. Peptide/HLA-specific cytotoxic activity and TCRV, gene usage of PDAK cells were analyzed. All transfers of PDAK cells, which showed peptide/HLA-specific lysis, were well-tolerated in all patients, and adverse effects (elevation of transaminase, fever, and headache) were observed primarily at grade 1, but in no case greater than grade 2. The generation of sufficient cells to treat the patients with 3x10⁷ PDAK cells/kg was feasible using our culture system, but we were able to generate and administer the dose of 1x10⁸ PDAK cells/kg in only one patient. One partial response (PR) of lung metastasis occurred in a pancreatic cancer patient who received 3x10⁷ Muc-1-PDAK cells/kg. The cytolytic units of PDAK cells in this patient appeared to be substantially higher compared to those in PD patients. TCR gene usage analysis on PDAK cells revealed preferential usage of TCRV, segments. These results suggest that adoptive immunotherapy using PDAK cells for cancer patients with antigen-positive lung metastasis is safe and feasible, and tumor response should be examined in a future clinical trial.