There has been an on-going debate on the advanced prostate cancer on-line support group about the issue of the efficacy of Provenge in light of the expectation of a person’s increasing PSA number while getting the treatment. For many men with advanced prostate cancer this is a reason they elect to pass on this treatment option. Many men even question the efficacy of the treatment.
I understand how difficult it is for anyone with advanced prostate cancer to go through a treatment and watch their PSA continue to increase and not question if a therapy is working. Most of the treatments we have do work quickly and we do see a PSA change if the therapy is effecting our cancer. Provenge does not work that way, it is not an instantaneous therapy and it will not lower or even stop the PSA from continuing to increase, this is the simple truth.
Provenge, when it works, takes time to train the immune system to fight the cancer. When the white blood cells are removed (the disease fighting cells) less than 1% of them are taken from the donor and treated with the PAP protein (which makes Provenge). The treated white blood cells are then returned to the donor and circulate through the body with the goal of sensitizing the other, untreated white blood cells to the cancer.
It does take time and yes, the PSA continues to increase while this process happens. This is scarey for anyone with advanced prostate cancer.
We have all been trained to monitor our PSA as a biomarker of our disease progression and yes, our disease does progress during this phase of treatment. Until the returned, treated white blood cells are able to “educate” the 99% of the untreated cells our disease will progress and our PSA will continue to climb. No question, this is nerve racking and most difficult for all of us. It does take nerves of steel.
This is why I believe it is important to have Provenge immediately when you become castrate resistant, while the disease (and the PSA) are still low.
Like any other treatment we have it will not work for everyone. Some of us will not receive any survival benefit, but more of us will than those who do not. I am told that here are men who are still alive today who were in the clinical trials used to obtain the FDA approval (I have no way to actual verify this statement).
Another concern that has been expressed on the group is that there has not been any non Dendreon sponsored studies that have been done to try and confirm the survival advantage of Provenge. This is true, there have not been any, but I would not expect to see any. This is a valid comment and should be considered when evaluating any research. However, the reality is that none of our current treatments (that I am aware of) has had any non sponsor research that duplicates their survival results. Why would a company that will not make any money from a product spend the millions of dollars required to do this research? Looking at who pays for research is always a good idea, but rejecting research conclusions when the results have been peer reviewed as they have been for Provenge should not be automatic.
The FDA carefully monitors the research protocol besides being actively involved in the actual research design of all clinical trials, including the three phase III trials of Provenge. Yes, the FDA has made mistakes and approved drugs that were eventually removed from the market. These removals, that I know of, are for safety issues, not efficacy issues.
Prior to its approval the FDA included an analyses of data from three separate Phase 3 trials (not one as some believe) in men with metastatic castrate resistant prostate cancer (Studies D9901, D9902A, and IMPACT). The data from all three studies was then integrated to examine the treatment effect in a larger group of men.
We can only hope that the scientists at Dendreon are able to develop a tool that will let us know if we are one of those individuals that can benefit from Provenge, until that time all we can do is hope that the statistical advantage (group trend) will work in to our own personal advantage. Again, my best recommendation is to jump on Provenge as soon as you become aware that you are castrate resistant.
Each of us should come to our own conclusion about any treatment available. It is important to we try and wrap our mind around as much information as possible, even when the information is in conflict. It is also important to always keep your mind open to new and additional information. It is our personal job to evaluate what we hear and learn and try and integrate this into what we feel will work for our self. The right answer for one of us is not necessarily the right answer for another. There is no universal right or wrong, just what we are comfortable with for our self.