Clinical and Immunologic Results of a Randomized Phase II Trial of Vaccination Using Four Melanoma Peptides Either Administered in Granulocyte-Macrophage Colony-Stimulating Factor in Adjuvant or Pulsed on Dendritic Cells

To determine clinical and immunologic responses to a multipeptide melanoma vaccine regimen, a randomized phase II trial was performed. Twenty-six patients with advanced melanoma were randomly assigned to vaccination with a mixture of four gp100 and tyrosinase peptides restricted by HLA-A1, HLA-A2, and HLA-A3, plus a tetanus helper peptide, either in an emulsion with granulocyte-macrophage colony-stimulating factor (GM-CSF) and Montanide ISA-51 adjuvant (Seppic Inc, Fairfield, NJ), or pulsed on monocyte-derived dendritic cells (DCs). Systemic low-dose interleukin-2 (Chiron, Emeryville, CA) was given to both groups. T-lymphocyte responses were assessed, by interferon gamma ELIspot assay (Chiron, Emeryville, CA), in peripheral-blood lymphocytes (PBLs) and in a lymph node draining a vaccine site (sentinel immunized node [SIN]). In patients vaccinated with GM-CSF in adjuvant, T-cell responses to melanoma peptides were observed in 42% of PBLs and 80% of SINs, but in patients vaccinated with DCs, they were observed in only 11% and 13%, respectively. The overall immune response was greater in the GM-CSF arm (P