DENDRITIC CELL-BASED IMMUNOTHERAPY OF PROSTATE-CANCER

The immunotherapy of cancer, based on eliciting or enhancing the body' s own capacity to mount an effective antitumor response, has produced encouraging early results in the areas of melanoma and renal-cell carc inoma. Such treatments utilizing dendritic cells (DC), immune cells th at are excellent antigen presenters, are especially promising. We perf ormed a phase I clinical trial assessing the administration of autolog ous DC pulsed with HLA-A0201 specific prostate-specific membrane antig en (PSMA) for the treatment of 51 men with hormone-refractory prostate cancer. Participants were divided into five groups receiving four or five infusions of peptides alone (PSM-P1 or PSM-P2; group 1 and 2, res pectively), autologous DC (group 3), or DC pulsed with PSM-P1 or P2 (g roup 4 and 5, respectively). No significant toxicity was observed. Imm une reactivity against PSM-P2 was detected in HLA-A2+ patients infused with DC pulsed with PSM-P1 or -P2 (group 4 and 5). An average decreas e in PSA was observed only in group 5. Seven partial responders were i dentified based on NPCP criteria + PSA. The excellent tolerance of thi s treatment approach, as well as the enhanced cellular responses, decr eased PSA levels, and partial clinical responses in some patients sugg ests that it holds great potential in prostate cancer therapy.