Immunotherapy and Prostate Cancer
In recent years, researchers have found that prostate cancers may respond to immunotherapy. Right now, only one immunotherapy treatment is approved by the Food and Drug Administration (FDA).
All other immunotherapy treatments may potentially be available through clinical trials. Your doctor can tell you if you may be eligible for one of these studies.
Types of Immunotherapy
The body’s immune system can recognize cancer cells, including prostate cancer. Like many other cancers, prostate cancer is able to avoid the immune system by “turning off” T cells. These are the blood cells most responsible for attacking foreign or abnormal cells in our bodies. Provenge® is an FDA-approved treatment vaccine. It is designed to boost the immune response to prostate cancer cells. It does this by turning on the T cells. The vaccine is used to treat men with advanced prostate cancer.
To be treated with this vaccine, doctors first remove a man’s immature immune cells. They then alter the cells by combining them with two substances. One is a manmade version of PAP, an enzyme produced by the prostate. PAP is made by most prostate cancer cells that have spread beyond the prostate. The second substance is called GM-CSF. This protein helps the T-cells grow and reproduce in the body.
Once they are returned to the man’s body, the new cells are activated and “trained” to attack prostate cancer. Provenge® has been shown to extend survival for men with advanced prostate cancer who no longer respond to hormones.
The side effects of Provenge® are generally mild to moderate. They may include a headache, fatigue, nausea, and joint pain. The course of treatment is relatively short—about 6 weeks.
Provenge® cannot be used for every man with advanced prostate cancer. It is used only for men who have few or no symptoms of their prostate cancer.
There are also only a few special facilities that can alter the immune cells and make the vaccine. For that reason, it is not widely available and can be expensive. To learn more about Provenge® and which centers offer this therapy, talk to your doctor.
PROSTVAC, like Provenge®, changes cells to attack prostate cancer cells. This vaccine was studied in a large, global Phase III trial in men with advanced prostate cancer, but did not show a significant benefit. However, PROSTVAC is also being tested with ipilimumab (Yervoy®) and in different settings in men with prostate cancer and you may be eligible for one of these trials.
GVAX contains prostate cancer cells that are exposed to radiation and then engineered to produce GM-CSF. It is often studied in clinical trials together with other immunotherapy drugs such as ipilimumab or with hormone therapy.
The Future of Immunotherapy for Prostate Cancer
Immunotherapy for prostate cancer, especially cancers that have spread and become resistant to other treatments, is showing promise. Many treatments are still being studied and are available only through clinical trials.
As scientists learn more about the relationship between cancer cells and the immune system, there will be more chances to develop new treatments to help improve the outcomes for men with prostate cancer.