Inclusion Criteria:

- Histologically documented adenocarcinoma of the prostate

- Metastatic disease as evidenced by soft tissue and/or bony metastases on bone scan
and/or computed tomography (CT) scan of the abdomen and pelvis at any time prior to
registration

- Castrate resistant prostate cancer

- Serum PSA ≤ 5.0 ng/mL

- Castration levels of testosterone (≤ 50 ng/dL; ≤ 1.74 nmol/L) achieved via medical or
surgical castration. Surgical castration must have occurred at least 3 months prior
to registration.

- ECOG performance status ≤ 1

- Adequate hematologic, renal, and liver function

- Negative serology tests indicating no active infection with human immunodeficiency
virus types 1 and 2 (HIV-1/2), human T cell lymphotropic virus types 1 and 2
(HTLV-I/II), and Hepatitis B and C viruses.

Exclusion Criteria:

- The presence of known brain metastases

- A requirement for systemic immunosuppressive therapy for any reason

- Treatment with any investigational vaccine within 2 years prior to registration

- Any previous treatment with sipuleucel-T

- Any previous treatment with ipilimumab (Yervoy[TM], MDX-010, or MDX-101) or denosumab
(Xgeva[TM])

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

- Known malignancies other than prostate cancer that are likely to require treatment
within 6 months of registration

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

- More than 2 chemotherapy regimens at any time prior to registration

- Treatment with any chemotherapy within 90 days of registration

- Received granulocyte colony-stimulating factor (G-CSF) or GM-CSF within 90 days prior
to registration

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

- Systemic corticosteroids. Use of inhaled, intranasal, intra-articular, and topical
steroids is acceptable, as is a short course (i.e., ≤ 1 day) of corticosteroids to
prevent a reaction to the IV contrast used for CT scans.

- Non-steroidal anti-androgens (e.g., bicalutamide, flutamide, or nilutamide)

- External beam radiation therapy or major surgery requiring general anesthetic

- Any other systemic therapy for prostate cancer including secondary hormonal
therapies, such as megestrol acetate (Megace®), diethylstilbestrol (DES), and
ketoconazole. Medical castration therapy is not exclusionary.

- Immunosuppressive therapy

- Treatment with any other investigational product

- Any infection requiring parenteral antibiotic therapy or causing fever (temperature >
100.5°F or 38.1°C) within 7 days prior to registration.

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