Vaccine Therapy in Treating Patients With Progressive Stage D0 Prostate Cancer

OBJECTIVES:

Primary

- Determine the safety and toxicity of TARP peptide vaccination vs TARP peptide-pulsed
dendritic cell vaccination in patients with biochemically progressing stage D0 prostate
cancer naïve to androgen-deprivation therapy.

- Determine the T-lymphocyte immune responses of these patients after treatment with TARP
peptide vaccination with Montanide® ISA-51 VG and sargramostim vs autologous dendritic
cells, as measured by tetramer staining, IFN-γ ELISPOT, and ^51Cr-release cytotoxic
T-lymphocyte assays.

Secondary

- Determine the effect of TARP peptide vaccination on serum prostate-specific antigen
doubling time (PSADT) in these patients.

- Correlate TARP tumor expression by in situ hybridization with immunologic reactivity.

OUTLINE: Patients are randomized to 1 of 2 treatment arms.

- Arm I: Patients receive vaccine comprising wild-type and epitope-enhanced TARP peptides
with Montanide® ISA-51 VG and sargramostim subcutaneously on weeks 3, 6, 9, 12, and
15*.

- Arm II: Patients receive vaccine comprising autologous, TARP peptide-pulsed dendritic
cells intradermally on weeks 3, 6, 9, 12, and 15*.

NOTE: *Patients that achieve PSA doubling time (PSADT) response at week 24 (i.e., ≥ 50%
increase in calculated PSADT OR a PSADT > 15 months) may receive an additional dose of
vaccine on week 36. All patients will receive a booster of vaccine at week 48.

Patients undergo PSADT response assessment at baseline and at weeks 12, 24, 36, 48, 60, 72,
84, and 96.

Patients undergo apheresis and blood sample collection periodically for biomarker analysis.
Samples are analyzed for humoral and cellular immune responses to TARP peptide vaccination
(e.g., CD4 and CD8 percent and absolute counts), NKT cells, and antigen-specific
T-lymphocyte responses by flow cytometry, tetramer staining, IFN-γ ELISPOT, and
^51Cr-release cytotoxic T-lymphocyte assay.