Inclusion Criteria:

   - Signed written informed consent

   - Age ≥ 18 years

   - Histologically-confirmed adenocarcinoma of the prostate

   - Hormone-refractory prostate cancer

   - Failed 1st-line docetaxel-containing regimen

   - No prior immunotherapy including:

      - Vaccines

      - GM-CSF

   - Minimum prostate-specific antigen (PSA) > 5 mg/dL and rising according to the PSA
   Consensus Criteria

   - Karnofsky Performance Status (KPS) > 60%

   - Eastern Cooperative Oncology Group (ECOG) Performance Status < 3

   - Life expectancy > 6 months

Exclusion Criteria:

   - Concomitant hormonal therapy other than luteinizing hormone-releasing hormone (LHRH)
   agonist

   - Use of herbal products known to decrease PSA levels

   - Use of supplements or complementary medicines, except for:

      - Conventional multivitamin supplements

      - Selenium

      - Lycopene

      - Soy supplements

      - Vitamin E

   - Initiation of bisphosphonates within one month prior to enrollment or throughout the
   study

   - Any prior radiopharmaceuticals (strontium, samarium) within 8 weeks prior to
   enrollment

   - Major surgery or radiation therapy completed < 4 weeks prior to enrollment

   - Any concomitant second malignancy other than non-melanoma skin cancer

   - Any concomitant serious infection

   - Any nonmalignant medical illness

   - Absolute neutrophil count (ANC) < 1,500/µL

   - Platelet count < 100,000 µL

   - Hemoglobin < 8 mg/dL

   - Total bilirubin greater than 1.5 x upper limit of normal (ULN)

   - Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) > 2.5 x ULN if no
   demonstrable liver metastases, or greater than 5.0 x ULN in presence of liver
   metastases

   - Ejection fraction < 50% as measured by echocardiogram (ECHO) or multigated acquisition
   (MUGA) scan

   - Noncompliance with study procedures