A Randomized, Multicenter, Single Blind Study in Men With Metastatic Androgen Independent Prostate Cancer to Evaluate Sipuleucel-T Manufactured With Different Concentrations of PA2024 Antigen

Inclusion Criteria:

For a subject to be eligible for participation in this study, all of the following
criteria must be satisfied.

- Histologically documented adenocarcinoma of the prostate.

- Metastatic disease.

- Progressive androgen independent prostate cancer.

- Serum PSA >= 5.0 ng/mL.

- Castrate level of testosterone (< 50 ng/dL) achieved via medical or surgical
castration.

- Men >= 18 years of age.

- Adequate hematologic, renal and liver function.

- In order to ensure the integrity of the study data is maintained, study participants
must be able to complete all study visits. For this reason, study participation is
limited to those who live in a permanent residence within a comfortable driving
distance (roundtrip within one day) to the clinical research site.

Exclusion Criteria:

A subject will not be eligible for participation in this study if any of the following
criteria apply.

- The presence of known lung, liver, or brain metastases, malignant pleural effusions,
or malignant ascites.

- A requirement for treatment with opioid analgesics for any reason within 21 days
prior to registration.

- Moderate to severe disease related pain.

- Eastern Cooperative Oncology Group (ECOG) performance status >= 2 .

- Use of non-steroidal antiandrogens within 6 weeks of registration.

- Anti-androgen withdrawal response.

- Treatment with chemotherapy within 3 months of registration.

- More than 2 chemotherapy regimens prior to registration.

- Initiation or discontinuation of bisphosphonate therapy within 28 days prior to
registration.

- Treatment with any of the following medications or interventions within 28 days of
registration:

- Systemic corticosteroids,

- External beam radiation therapy or surgery,

- PC-SPES (or PC-SPEC) or Saw Palmetto,

- Megestrol acetate (Megace(R)), diethylstilbesterol (DES), or cyproterone
acetate, ++Ketoconazole,

- 5-alpha-reductase inhibitors,

- High dose calcitriol [1,25(OH)2VitD] (i.e., > 0.5 mg/day).

- Any other systemic therapy for prostate cancer (except for medical castration).

- Treatment with any investigational vaccine within 2 years of registration or
treatment with any other investigational product within 28 days of registration.

- Participation in any previous study involving sipuleucel-T, regardless of whether the
subject received sipuleucel-T (APC8015) or placebo.

- Known pathologic long-bone fractures, imminent pathologic long-bone fracture
(cortical erosion on radiography > 50%) or spinal cord compression.

- A history of stage III or greater cancer, excluding prostate cancer. Basal or
squamous cell skin cancers must have been adequately treated and the subject must be
disease-free at the time of registration. Subjects with a history of stage I or II
cancer must have been adequately treated and been disease-free for >= 3 years at the
time of registration.

- A requirement for systemic immunosuppressive therapy for any reason.

- A history of allergic reactions attributed to compounds of similar chemical or
biologic composition to sipuleucel-T or GM-CSF.

- Any infection requiring parenteral antibiotic therapy or causing fever (temp > 100.5F
or > 38.1C) within 1 week prior to registration.

- Any medical intervention or other condition which, in the opinion of the Principal
Investigator or the Dendreon Medical Monitor, could compromise adherence with study
requirements or otherwise compromise the study's objectives.