Prostatic Acid Phosphatase (PAP) Vaccine in Patients With Prostate Cancer

Phase I Study of a DNA-based Vaccine Targeting Prostatic Acid Phosphatase (PAP) in Patients With Stage D0 Prostate Cancer

The investigators are trying to find new methods to treat prostate cancer. The approach they investigators are taking is to try to enhance patients own immune response against the cancer. In this study the investigators will be testing the safety of a vaccine that may be able to help the body fight prostate cancer.

The purpose of this research is to determine the safety of serial intradermal vaccinations of a DNA vaccine encoding human PAP, with GM-CSF as a vaccine adjuvant, in subjects with stage D0 prostate cancer. In addition, to determine whether PAP-specific IFNУ-secreting CD8+ T cells can be augmented in subjects with stage D0 prostate cancer by means of immunization with a plasmid DNA vaccine encoding PAP.

This is a phase I design where patients will receive the vaccine pTVG-HP with rhGM-CSF administered i.d. biweekly for 6 total doses. There will be three escalating dose cohorts. The dosing cohort considered to be the maximum tolerated dose level will be expanded up to a total of 16 patients.

Inclusion Criteria:

• Must have histologic diagnosis of adenocarcinoma of the prostate
• Must have completed local therapy by surgery and/or ablative radiation therapy at least 2 months prior to entry.
• Must have clinical stage D0 disease defined by the following: In patients treated by surgery, serum PSA values must be > 2 ng/ml by two measurements at least two weeks apart. In patients treated with ablative radiation therapy, three consecutive increases in serum PSA must be documented, with at least a one month interval between values with the finalPSA > 2ng/ml.
• Prior history of a second malignancy is allowed if treated with curative intent disease free for > 5 years.
• Karnofsky performance score of > 70

Exclusion Criteria:

• No evidence of immunosuppression or have been treated with immunosuppressive therapy, such as chemotherapy, chronic treatment dose corticosteroids (greater than the equivalent of 10 mg prednisone per day), or radiation therapy to >30% of the bone marrow, within 6 months of the first vaccination.
• Must not be on concurrent androgen ablative (hormonal) therapy, or must have completed this therapy at least one month prior to study entry.
• Must not have demonstrated PSA progression during any prior hormonal therapy or chemotherapy.
• Must not have known evidence of bone metastases or non-regional lymph node involvement (stage D2 disease) as determined by bone scan or CT scan. -Must not have been treated previously with another investigational anti- tumor vaccine.