Placebo-Controlled Phase III Trial of Immunologic Therapy with Sipuleucel-T (APC8015) in Patients with Metastatic, Asymptomatic Hormone Refractory Prostate Cancer

PURPOSE: Sipuleucel-T (APC8015) is an investigational immunotherapy product designed to stimulate T-cell immunity against prostatic acid phosphatase. A phase III study was undertaken to evaluate the safety and efficacy of sipuleucel-T in a placebo-controlled study. PATIENTS AND METHODS: A total of 127 patients with asymptomatic metastatic hormone refractory prostate cancer (HRPC) were randomly assigned in a 2:1 ratio to receive three infusions of sipuleucel-T (n = 82) or placebo (n = 45) every 2 weeks. On disease progression, placebo patients could receive APC8015F, a product made with frozen leukapheresis cells. RESULTS: Of the 127 patients, 115 patients had progressive disease at the time of data analysis,…