Immunotherapy
For Prostate Cancer

What Makes Immunotherapy for Prostate Cancer a Promising Treatment?

Reviewed by:

Sumit K. Subudhi, MD, PhD
The University of Texas MD Anderson Cancer Center

Immunotherapy for prostate cancer includes two FDA-approved treatment options and is a promising area of research for metastatic cancer treatment.

The prostate is a small, walnut-shaped gland that is part of the male reproductive system. The prostate is located just below the bladder, where it surrounds the top portion of the urethra (the tube that drains urine from the bladder). The main function of the prostate gland is to secrete fluid that nourishes and protects sperm.

As the second most common male cancer in the world, prostate cancer affects roughly 1.3 million people and kills more than 360,000 people each year, which represents about 4% of all cancer deaths worldwide. In the United States alone, there will be roughly 290,000 new cases and more than 35,000 deaths in 2023. Prostate cancer, the eighth leading cause of cancer-related deaths, will impact an estimated 1 in every 7 men in their lifetimes.

In its early stages, prostate cancer is highly treatable, with five-year survival rates close to 100%. Once prostate cancer has metastasized, however, the 5-year survival rate  falls to less than 30%, highlighting a significant need for more effective treatment of advanced stage disease.

Prostate Cancer Treatment Options

Conventional treatments for early-stage prostate cancer include surgery and radiation. Hormonal therapy, which can reduce levels of the male hormones (androgens like testosterone) that lead to tumor growth, is also used to treat early-stage tumors. For advanced or metastatic prostate cancer, chemotherapy is also a treatment option.

Immunotherapy is class of treatments that take advantage of a person’s own immune system to help kill cancer cells. There are currently three FDA-approved immunotherapy options for prostate cancer.

Cancer Vaccines

• Sipuleucel-T (Provenge®): a vaccine composed of patients’ own immune cells, which have been stimulated to target the PAP (prostatic acid phosphatase) protein highly expressed on prostate cancers; approved for subsets of patients with advanced prostate cancer

Immunomodulators

• Dostarlimab (Jemperli): a checkpoint inhibitor that targets the PD-1/PD-L1 pathway; approved for subsets of patients with advanced prostate cancer that has DNA mismatch repair deficiency (dMMR)
• Pembrolizumab (Keytruda®): a checkpoint inhibitor that targets the PD-1/PD-L1 pathway; approved for subsets of patients with advanced prostate cancer that has high microsatellite instability (MSI-H), DNA mismatch repair deficiency (dMMR), or high tumor mutational burden (TMB-H)

In cases where the patient’s prostate cancer is resistant to testosterone level reduction via hormone therapy, treatment options are few. Several immunotherapy options are currently in clinical trials for patients with advanced prostate cancer.

CRI’s Impact in Prostate Cancer

Since 1953, the Cancer Research Institute has provided almost 100 grants to research and clinical trial initiatives in the field of prostate cancer, totaling almost $25 million in financial support.

In fact, $9 million of this funding was given in conjunction with the CRI Prostate Cancer Initiative—a program started in 1996 to support clinical research promising the most readily available and immediate benefits to prostate cancer patients. The CRI Prostate Cancer Initiative also aimed to improve prostate cancer patient outreach and increase public awareness of the disease.

Our organization has also participated in cooperative efforts to develop informative resources and materials for prostate cancer patients in close partnership with national nonprofit ZERO’s patient support program.

Some work and recent findings by CRI investigators that are advancing the understanding and treatment of prostate cancer include:

• In 2011, CRI researchers Alex Knuth, MD, and Maries van den Broek, PhD, reported that the CT10/MAGE-C2 cancer-testis antigen is frequently expressed in advanced prostate cancer, indicates a higher risk for biochemical recurrence (i.e., increase in PSA values) after radical surgery, and could, therefore, potentially serve as a marker of tumor progression that can help predict a patient’s clinical course and assist doctors in making treatment decisions.
• Two CRI postdoctoral fellows at the University of California, San Diego, Xiaoyuan Song, PhD, and Chunyu Jin, PhD, both in the laboratory of Michael G. Rosenfeld, MD, found a protein that is involved both in inhibiting androgen receptor target genes, such as prostate-specific antigen (PSA), as well as in regulating the inflammatory properties of innate immune cells called macrophages.
• Peter Savage, PhD, a CRI investigator at the University of Chicago, obtained the first direct insight into the basic biology of tumor-infiltrating regulatory T cells in a model of prostate cancer.
• CRI Investigators Padmanee Sharma, MD, PhD, and Sumit Subudhi, MD, PhD, of MD Anderson Cancer Center, have conducted innovative studies testing the effects and immune correlates of responses in patients with advanced prostate cancer treated with anti-CTLA-4 checkpoint blockade.
• In 2019, the CRI Anna-Maria Kellen Clinical Accelerator in collaboration with the Parker Institute for Cancer Immunotherapy launched a prostate cancer platform clinical trial evaluating different treatment combinations including the PD-1 inhibitor nivolumab.

See what prostate cancer-specific research we’re currently funding. With your help, we can fund more research and revolutionize the way cancer is treated, forever—curing more people and saving more lives.