Autologous dendritic cells transfected with total renal tumor RNA have been shown to be potent stimulators of CTLs and antitumor immunity in vitro. A Phase I trial was conducted to evaluate this strategy for feasibility, safety, and efficacy to induce tumor-specific T-cell responses in subjects with metastatic renal cell carcinoma. Renal tumor RNA-transfected dendritic cells were administered to 10 evaluable study patients with no evidence of dose-limiting toxicity or vaccine-related adverse effects including autoimmunity. In six of seven evaluable subjects, expansion of tumor-specific T cells was detected after immunization. The vaccine-induced T-cell reactivities were directed against a broad set of renal tumor-associated antigens, including telomerase reverse transcriptase, G250, and oncofetal antigen, but not against self-antigens expressed by normal renal tissues. Although most patients underwent secondary therapies after vaccination, tumor-related mortality of the study subjects was unexpectedly low with only 3 of 10 patients dying from disease after a mean follow-up of 19.8 months. These data provide a scientific rationale for continued clinical investigation of this polyvalent vaccine strategy in the treatment of metastatic renal cell carcinoma and, potentially, other cancers.