Dendritic cell-tumor fusion vaccines for renal cell carcinoma.

Renal cell carcinoma is a malignant disease that demonstrates resistance to standard chemotherapeutic agents. A promising area of investigation is the use of cancer vaccines to educate host immunity to specifically target and eliminate malignant cells. Dendritic cells (DCs) are potent antigen-presenting cells that are uniquely effective in generating primary immune responses. DCs that are manipulated to present tumor antigens induce antitumor immunity in animal models and preclinical human studies. A myriad of strategies have been developed to effectively load tumor antigen onto DCs, including the introduction of individual peptides, proteins, or tumor-specific genes, as well as the use of whole tumor cells as a source of antigen. A promising approach for the design of cancer vaccines involves the fusion of whole tumor cells with DCs. The DC-tumor fusion presents a spectrum of tumor-associated antigens to helper and cytotoxic T-cell populations in the context of DC-mediated costimulatory signals. In animal models, vaccination with DC-tumor fusions resulted in protection from tumor challenge and regression of established metastatic disease. We have conducted phase 1 dose escalation studies in which patients with metastatic breast and renal cancer underwent vaccination with DC-tumor fusions. Twenty-three patients underwent vaccination with autologous DC-tumor fusions. Vaccination was well tolerated without substantial treatment-related toxic effects. Immunologic responses and disease regression were observed in a subset of patients. Future studies will explore the effect of DC maturation and cytokine adjuvants on vaccine potency.