Practical guide to immunotherapy in castration resistant prostate cancer: the use of sipuleucel-T immunotherapy

Introduction: New treatment options for metastatic castration resistant prostate cancer (mCRPC) have become available over the last few years should primary treatments and androgen deprivation therapies fail. While historically not considered to be amenable to immunotherapy, the treatment of advanced prostate cancer using this approach is an area of intense interest and now clinical application. Materials and methods: Recent literature on castration resistant prostate cancer management with a focus on immunotherapeutic strategies was reviewed. Mechanisms of action involving the immunologic treatment of cancer were identified. Agents in clinical trials with near term application in prostate cancer were also identified. Results: Numerous immunotherapeutic agents for mCRPC are in current clinical trials. The autologous, active cellular immunotherapy, sipuleucel-T, which utilizes a patient's own antigen-presenting cells, is the only Food and Drug Administration (FDA) approved agent. It provides a 4.1 month survival advantage. Other investigational agents in this area include GVAX, a whole cell irradiated vaccine, and a vaccinia-PSA-TRICOM pox virus based approach, all in phase III trials. Immunecheckpoint inhibitors that enhance T-cell activity and potentiate antitumor effects are also promising. Conclusions: A first in class novel treatment modality, sipuleucel-T, is available in the United States for mCRPC. Other immunothera pies are in development and may be available in the near future. Understanding the detailed patient evaluation, initiation and administration of sipuleucel-T as described in this paper, will allow this novel cancer immunotherapy to be better understood and potentially benefit a larger group of appropriately selected patients.