Increasing the Potency of Monocyte-derived DC Vaccines

Baylor Research Institute, Dallas TX

Investigators

Linked publications & trials

Abstract

We found that administration of peptide-loaded CD34-DC vaccine can lead to therapeutic immunity in[unreadable] metastatic melanoma. This "composite vaccine" includes several DC subsets, the combination of which may[unreadable] contribute to vaccine efficacy. We have also found that culturing monocytes with GM-CSF and TNF yields a[unreadable] composite vaccine that is phenotypically different from the "traditional" GM-CSF/IL-4 monocyte-derived DCs,[unreadable] while it appears similar to CD34-DCs. Such vaccine would offer a great advantage for clinical trials as it can[unreadable] be generated within 3 days and does not require G-CSF treatment of the patients. The feasibility of[unreadable] administering such vaccine has already been shown with ten patients. We also found that monocyte-derived[unreadable] IL4-DCs loaded with killed allogeneic melanoma cells induce clinical and immunological responses. We[unreadable] hypothesize that monocyte-derived composite DC vaccines loaded with killed allogeneic melanoma cells[unreadable] activated with TLR agonists ex vivo will induce clinical and immunological responses. Therefore, AIM 1 will[unreadable] optimize the TNF-MDCs vaccine loaded with killed allogeneic Colo829 melanoma cells and activated via[unreadable] TRLs and CD40. AIM 2 will establish in vivo the immunogenicity of TNF-MDCs loaded with killed allogeneic[unreadable] melanoma cells in patients This will be a Phase l/ll single arm clinical trial which Primary Objective is[unreadable] induction of melanoma antigen-specific CD8+T cells and Secondary Objective is induction of objective[unreadable] clinical responses. The trial is powered based on the rate of induction of melanoma-specific CD8+T cell[unreadable] immunity and will accrue up to 51 metastatic melanoma patients. Interim analyses will be conducted after 9[unreadable] and 24 patients are enrolled to assess toxicity and immunogenicity. Immune responses will be assessed[unreadable] using EPIMAX strategy. The 2 main quantitative assays involve melanoma antigen-specific IFN-gamma[unreadable] release (effector memory cells) and cell proliferation (CFSE and flow cytometry; recall memory) by T cells in[unreadable] short term PBMCs cultures with selected melanoma antigen-peptides. AIM 3 will determine the breadth and[unreadable] the quality of melanoma-specific CD8+T cell immunity in patients vaccinated with composite DCs loaded with[unreadable] killed allogeneic melanoma cells. We will determine 1) the breadth of immune response, i.e. beyond the five[unreadable] antigens selected for immunomonitoring; 2) the function of elicited CD8+T cells; and 3) the authentic killing of[unreadable] melanoma tumors in vivo in the OncoHumouse.[unreadable]