Study of Sipuleucel-T With or Without Continuing New Hormonal Agents in Metastatic Prostate Cancer

Inclusion Criteria: * Asymptomatic or minimally symptomatic metastatic prostate cancer, and the diagnosis of prostate cancer needs to be histologically confirmed by biopsy of the prostate or a metastatic lesion * On combined ADT with LHRH analog and a NHA (enzalutamide, apalutamide or abiraterone) for metastatic prostate cancer with PSA progression, but no imaging progression based on the prostate cancer working group (PCWG) 3 criteria * Age 18 or above * ECOG performance status 0 or 1 * Participants must have adequate organ and marrow function as defined below: * Absolute neutrophil count ≥1,000/mcL * Platelets ≥100,000/mcL * Hemoglobin \> 10 g/dl * AST(SGOT)/ALT(SGPT) ≤3 × institutional ULN * Creatinine 1.5 ≤ institutional ULN * Human immunodeficiency virus (HIV)-infected participants on effective anti-retroviral therapy with undetectable viral load within 6 months are eligible for this trial. * For participants with evidence of chronic hepatitis B virus (HBV) infection, the HBV viral load must be undetectable on suppressive therapy, if indicated * Participants with a history of hepatitis C virus (HCV) infection must have been treated and cured. For participants with HCV infection who are currently on treatment, they are eligible if they have an undetectable HCV viral load * Participants with a prior or concurrent malignancy whose natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of sipuleucel-T are eligible for th…