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New Improvements for Prostate Cancer Immunotherapy

Jun 25, 2018 10:08:00 AM / by Stacy Matthews Branch, DVM, PhD

3D illustration showing viruses infecting prostate gland which develops cancerous tumorImmunotherapy is a highly studied treatment for cancers, and is now being considered for the treatment of prostate cancer, the most common cancer diagnosis for U.S. men.

Prostate cancer is the most common cancer diagnosis for men in the U.S. and a leading cause of cancer-related death. A heavily studied cancer treatment approach is immunotherapy and is increasingly being investigated for the treatment of prostate cancer. Although results of immunotherapy trials for prostate cancer present many challenges (relapse and development of resistance in some patients), they still show potential therapeutic promise.

Sipuleucel-T is the first therapeutic vaccine approved for use in human cancer. This vaccine can activate T-cell responses and subsequent cytokine release. Despite the limited clinical benefit of Sipuleucel-T, the development of this therapy has bolstered studies for the development of other immunotherapeutic agents for prostate cancer. The cellular vaccine GVAX is made from cells of prostate cell lines and are modified to express GM-CSF. GVAX can induce T cells to respond to tumor-associated antigens, can be massed produced, and does not rely on HLA matching; however clinical trials for GVAX were halted due to an increased risk of death. 

PROSTVAC is a vaccine made of poxviral vectors and engineered to express PSA. Although an increase in overall survival was observed with this vaccine, progression-free survival was not improved. DNA vaccines are also showing promise; these vaccines are plasmids that encode specific tumor antigens. One example, pTVG-HP, is designed to produce human prostate enzyme (PAP)-specific T-cell responses affecting PSA doubling time. Adenoviral vaccines have been designed to be applied directly to prostate tumors to induce local cytotoxicity and can be combined with surgery or radiation. 

Dendritic cell vaccines increased overall survival in prostate cancer clinical trials and various formulations are in the early development stages. Bacterial vaccines made with Listeria monocytogenes can induce antigen-specific tumor responses in mouse models of prostate cancer. Personalized peptide vaccines (PPV) consist of cancer-associated peptides that can be recognized by and activate T cells. Early trials show that PPV vaccines can affect PSA doubling time and improve overall survival. Many studies are ongoing to determine the clinical benefit of emerging immunotherapeutic approaches and their use in conjunction with existing treatments. 

Learn more about dendritic cells, as well as other cells and tissues, HemaCare provides to support your research. 

 

Reference:

Immunotherapy for Prostate Cancer: Where Do We Go From Here?—PART 1: Prostate Cancer Vaccines | Cancer Network. (2018). Cancernetwork.com. Retrieved 10 May 2018, from http://www.cancernetwork.com/prostate-cancer/immunotherapy-prostate-cancer-where-do-we-go-herepart-1-prostate-cancer-vaccines

Topics: new immunotherapy advances, Cancer, Dendritic Cells, Vaccine Research, Immunotherapy (Immunology)

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