Sipuleucel-T in Metastatic Castrate Resistant Prostate Cancer

Inclusion Criteria: * Previously randomized in Dendreon's P-11 study (NCT00779402) and received at least one infusion of sipuleucel-T * Radiologic evidence of metastasis * Castrate resistant prostate cancer. Subjects must have current or historical evidence of disease progression concomitant with surgical or medical castration, as demonstrated by PSA progression OR progression of measurable disease OR progression of non-measurable disease * Castrate level of testosterone (\< 50 ng/dL) achieved via medical or surgical castration * Adequate hematologic function Exclusion Criteria: * Eastern Cooperative Oncology Group (ECOG) performance status \> 2 * Treatment with chemotherapy within 3 months prior to registration * Treatment with systemic corticosteroids, abiraterone acetate, external beam radiation therapy, or any investigational product for prostate cancer within 28 days prior to registration * Treatment with commercial sipuleucel-T (Provenge®) * Current or imminent pathologic long-bone fracture or spinal cord compression * Known malignancies other than prostate cancer likely to require treatment within 6 months following 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 antibiotic therapy or causing fever within 1 week prior to registration * Any surgery requiring general anesthetic within 28 days prior to registration