A phase I trial of tumor lysate-pulsed dendritic cells in the treatment of advanced cancer.

Abstract

The objectives of this study were to assess the toxicity and immunological response induced by the intradermal (i.d) administration of tumor lysate-pulsed dendritic cells (DCs). Patients with stage IV solid malignancies were treated in cohorts that received 10(6), 10(7), and 10(8) DCs i.d. every 2 weeks for three vaccines. Each vaccine was composed of a mixture of half DCs pulsed with autologous tumor lysate and the other half with keyhole limpet hemocyanin (KLH). Peripheral blood mononuclear cells (PBMCs) harvested 1 month after the last immunization was compared with pretreatment PBMCs for immunological response. Delayed-type hypersensitivity reactivity to tumor antigen and KLH was also assessed. Fourteen patients received all three vaccines and were evaluable for toxicity and/or immunological monitoring. There were no grade 3 or 4 toxicities associated with the vaccines or major evidence of autoimmunity. Local accumulation of CD4(+) and CD8(+) T cells were found at the vaccination sites. There was a significant proliferative response of PBMCs to KLH induced by the vaccine. In 5 of 6 patients, the vaccine resulted in increased IFN-gamma production by PBMCs to KLH in an ELISPOT assay. Using the same assay, 3 of 7 patients' PBMCs displayed increased IFN-gamma production in response to autologous tumor lysate. One patient with melanoma also was observed to have an increased frequency of MART-1- and gp100-reactive CD8(+) T cells after vaccination. By delayed-type hypersensitivity testing, 8 of 9 and 4 of 10 patients demonstrated reactivity to KLH and autologous tumor, respectively. Two patients with melanoma experienced a partial and a minor response, respectively. The administration of tumor lysate-pulsed DCs is nontoxic and capable of inducing immunological response to tumor antigen. Additional studies are necessary to improve tumor rejection responses.