Study of Sipuleucel-T W/ or W/O Radium-223 in Men With Asymptomatic or Minimally Symptomatic Bone-MCRPC

This is a randomized study designed to assess the antigen-specific immune response of sipuleucel-T with or without radium-223. Eligible subjects will be registered and randomly assigned in a 1:1 ratio to receive sipuleucel-T and radium-223 or sipuleucel-T alone. Subjects in both arms (sipuleucel-T and radium) will undergo a standard 1.5 to 2.0 blood volume leukapheresis, followed approximately 3 days later by an IV infusion of sipuleucel-T. This process will occur a total of 3 times at approximately 2-week intervals. Subjects in Arm 1 will receive a total of 6 infusions of radium-223 at IV dose of 50 kBq/kg at 4-week interval. All participants are allowed to receive the best supportive care which includes secondary hormonal manipulation as required. No chemotherapy, external-beam radiation, or other radionuclides are allowed while on active treatment but are permitted after completion of active treatment. Glucocorticoid-containing treatments should be minimized to less than the equivalent dose of prednisone 10mg daily if feasible for the 3 months following sipuleucel-T therapy. All patients continue medical or surgical castration during treatment.