難治性固形癌に対する癌抗原ペプチドパルス樹状細胞を用いた癌ワクチン療法 : トランスレーショナルリサーチとしての展開

Dendritic cells (DCs) are the most potent antigen-presenting cells. DCs pulsed with peptides of tumor-associated antigens (TAA) have been used in cancer immunotherapy. An early clinical study demonstrated the safety of these trials, but the clinical effect was not sufficient. Most studies have used immature DCs generated from peripheral blood monocytes with granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4). Here, we conducted phase I clinical trial of active immunotherapy using mature DCs induced by a streptococcus derivatives OK-432. DCs were generated from blood monocytes by culturing with GM-CSF and IL-4 for 6 days and then GM-CSF, IL-4 and OK-432 for 2 days. Before injection, DCs were pulsed with MAGE-3 peptide (IMPKAGLLI), which is restricted for HLA-A*2402, and keyhole limpet hemocyanin (KLH) as a control antigen. We selected HLA-A*2402-positive patients who had advanced solid tumors expressing MAGE-3 mRNA. DC vaccine was administered subcutaneously every 2 weeks for a total of four vaccinations in a dose-escalation design at the dose level per cohort of 0.1 (Group 1), 0.3 (Group 2) and 1 (Group 3) ×10８DCs/injection. Immunological monitoring with delayed type hypersensitivity (DTH) reaction and MHC tetramer was performed. Three patients with advanced solid tumor (two lung cancer and one melanoma patients) were so far enrolled in Group 1 of this study. This protocol was well tolerated. A mild fever (Grade 1 to 2) and local reaction of injection site (erythema and induration : Grade 1) were found in all patients. DTH for MAGE-3 peptide became to be positive after forth vaccination in one patient. The decrease of tumor marker (CEA) was found in one patient. However, clinical responses in all three patients were not observed. These results indicated that vaccination with mature DCs (0.1×10８DCs/injection) was safe and feasible, but further analysis using the higher dose of DCs was required to assess the immunological and clinical responses.

四国医学雑誌 : http://www.tokushima-u.ac.jp/med/research/shikoku_acta_medica.html