Hormone Refractory Prostate Cancer: Focus on Sipuleucel-T

Sipuleucel-T is a vaccine based on autologous antigen presenting cells that are loaded with an antigen-cytokine (prostatic acid phosphatase and granulocyte-macrophage colony-stimulating factor) fusion product. Sipuleucel-T is given intravenous in weeks 0, 2, and 4. Within phase I–III trials, patients with metastatic hormone-refractory prostate cancer have been treated. In these trials an activation of the immune system could be demonstrated. Also, some clinical responses could be documented. Moreover, in a placebo-controlled phase III trial including 127 patients a statistical significantly prolongation of survival was achieved. Side effects from the vaccine are rather mild and included fever, myalgia, fatigue and others. The Food and Drug Administration in the United States requested further data before possible approval of sipuleucel-T.