Your immune system identifies foreign organisms that invade your body and then eliminates them. Cancer is the out-of-control growth of your own native cells, so your immune system does not recognize your cancer as a foreign organism and does not attack it.
There has been great effort and cost expended over the years to create ways for the immune system to respond to cancer. The goal is to develop immunotherapy that “tricks” your immune system into recognizing your cancer cells as “invaders” and then attacking and destroying them. Immunotherapy is at the leading edge of cancer treatment.
We men are fortunate because prostate cancer has gleaned a significant portion of immunotherapy development dollars. In May 2010, the FDA approved Sipuleucel-T (Provenge), the first immunotherapy approved for the treatment of any type of cancer.
What we have learned is that immunotherapy takes time to work. This is very different than in other therapies here we expect to see immediate responses in both our PSA and in evidence of slowed disease progression in our scans.
Immunotherapy takes time to “recruit” the immune system to go into high gear and attack the cancer. This means that the earlier in the prostate cancer disease stage the more time it will have to kick into gear. Immune therapy should be started as soon as possible when there is evidence that you have become castrate resistant.
Immunotherapy uses your own natural immune system to fight the cancer.
Following immunotherapy, do not expect to see a decline in your PSA and a halt in disease progression on scans. These markers will not tell you if the treatment will be effective, all we have is the knowledge from the clinical trial data that it does extend life. Six months or a year into your treatments you will still not know if you would have had even worse numbers without the treatment. Remember what we said at the beginning of this guide: it’s pointless to ponder what might have been. Yesterday doesn’t matter, only today does.
Provenge, the first FDA approved immunotherapy for any cancer, is considered a vaccine, but it differs from traditional vaccines. Most vaccines are a defensive treatment, to prevent our developing an ailment. Provenge, like all other cancer vaccines, is administered after prostate cancer has developed. Provenge is a personalized treatment that teaches your immune system to recognize your prostate cancer as a foreign body and then fight it.
The approval of Provenge is very specific. It is limited to men with castrate resistant prostate cancer, who have metastatic disease, and who experience minimal or no symptoms (pain) from their cancer.
Provenge is administered in a unique fashion. A process called leukapheresis removes dendritic cells, (T cells) a type of white blood cell, from your body. This is accomplished by drawing blood from your arm or via a catheter that has been surgically placed in one of your veins. A special machine extracts the dendritic cells from your blood and returns the remainder of your blood product to you. Your body quickly replenishes dendritic cells, so you will experience no long-term effects from their removal.
The removed dendritic cells are then shipped to a manufacturing plant where a prostate cancer antigen and some immune stimulating molecules are attached to the surface of your own dendritic cells. These “supercharged” dendritic cells are then shipped back to the leukapheresis center to be returned to you via an infusion.
Provenge is administered using three separate leukapheresis removal and replacement sessions over about a one-month time period.
The fact that Provenge has no effect on PSA or disease progression causes great confusion about the viability of the treatment. Many men do not believe that Provenge works since their PSA will continue to climb after treatment. But the clinical trials were clear: Provenge does extend life, which is the “gold standard” of all cancer treatments. We believe Provenge works best for men with low PSA scores and disease burden since these will continue to progress while undergoing treatment.
Additionally, Provenge needs time to build up your immune system. Despite the unclear evidence for this statement, it may make sense during the time it takes to have immunotherapy treatments as well as for a period after the treatment has been administered for you to avoid undergoing any other type of treatment such as chemotherapy that may compromise the immune system. Whether to decide to delay an additional treatment or move directly to it should be a decision that is based on your general physical health, how far your cancer has progressed and a complete discussion with your doctor.
The most common side effects of Provenge are minimal and brief in duration: chills, fatigue, fever, back pain, nausea, joint ache, and headache (flu-like symptoms). These would develop within a day or two of the infusion and usually last for only a day or two.
As we noted above, many men are concerned because there is no clear metric to know if Provenge is helping. This is especially frustrating because both PSA and disease progression will often continue even while receiving treatment. Yet a new analysis shows that Provenge may have a median survival (life extension) advantage of as much as 7.8 months—the largest thus far observed for any late stage cancer treatment.
Another study showed that the largest immune boost occurred in men in an earlier stage of the disease, underscoring the importance of getting Provenge as early as possible after becoming castrate resistant.
Arrange to have Provenge as soon as you become castrate resistant.
Currently there are a number of studies evaluating Provenge at different disease stages as well as in combination with other drugs and for the development of biomarkers. The advanced prostate cancer blog (www.advancedprostatecancer.net) will keep you informed about these study findings.
For more information go to: Dendreon on Call at 1-877-336-3736 or go to www.Provenge.com
In addition to Provenge, there have been significant developments of new candidate vaccines and therapeutic antibodies designed to target prostate cancer. As of 2012, around 30 different immunotherapy candidates are in development: 16 prostate cancer vaccines and 14 prostate cancer-targeting antibodies. Of these candidates, eight are in Phase I trials, while nineteen are in Phase II and Phase III trials (9 vaccines and 10 antibodies).
These various investigational vaccines and antibodies are targeting more than fifteen different prostate cancer-associated antigens or other prostate cancer-associated proteins. There are twenty-five companies currently involved in this research: 20 small- and medium-sized enterprises and 5 multinational pharmaceutical companies.
The potential and motivation for pharmaceutical companies is clear and we hope to see new immunotherapy products in the not too distant future.