Sequencing of Sipuleucel-T and ADT in Men With Non-metastatic Prostate Cancer

Multicenter, randomized, open-label study, with subjects allocated (1:1) to 1 of 2 study arms, using a stratified randomization based on:

• Prostate-specific antigen doubling time (PSADT): ≤ 3 months or > 3 months and ≤ 12 months. • Primary therapy: radical prostatectomy (RP) or radiation, including brachytherapy, (XRT) or RP + XRT.

Arm 1: Subjects received one infusion of sipuleucel-T every two weeks for a total of three infusions. Two weeks after the third sipuleucel-T infusion, subjects started ADT with 45 mg leuprolide acetate depot injection (Eligard® 45 mg). An additional leuprolide acetate injection was administered at 6 months after the first injection for a total of 2 injections and 12 months of ADT.

Arm 2: Subjects started ADT with 45 mg leuprolide acetate depot injection (Eligard® 45 mg) 12 weeks before infusion 1 of sipuleucel-T. An additional leuprolide acetate injection was administered at 6 months after the first injection for a total of 2 injections and 12 months of ADT. Twelve weeks after the initial leuprolide 45 mg depot injection, subjects began one infusion of sipuleucel-T every two weeks for a total of three infusions.

Cellular and humoral immune responses were assessed for Arm 2 subjects at 12, 8, and 4 weeks pre infusion 1, and in all subjects (both arms) at pre-leukapheresis 1, 2, and 3, and post-infusion 1, 2 and 3, and at the following time points after the third infusion: Weeks 2, 6, and 12 and Months 6, 9, 12, 15, 18, 21, and 24.

Safety assessments included adverse event (AE) monitoring, laboratory tests (complete blood count (CBC) and serum chemistry), vital signs, Eastern Cooperative Oncology Group (ECOG) performance status, physical examination, as well PSA and testosterone monitoring. The study was complete at the 27-Month visit for Arm 1 and the 24-Month visit for Arm 2.