Important things you need to know about clinical trials

Patient participation in clinical trials is critical to the ongoing development of better and better therapies for the management of prostate cancer. However, participation in clinical trials can be a big commitment, and it can come with a number of very specific risks that you need to be aware of.

There are very complete discussions of clinical trials for patients available on the web site of the National Cancer Institute and also at You can also see a list of questions you might want to ask on another page of this site. (They have been derived from a similar list on the National Cancer Institute’s web site.) What we have tried to list out below are some of the issues that may be really critical for prostate cancer patients.

  • In some trials it is possible that you will not receive the investigational drug at all because there is nothing effective to compare it to. In such trials you will either receive the investigational drug or you will receive a placebo (a sugar pill). Some patients just aren’t willing to consider the possibility of receiving placebo, but only by giving a placebo can researchers work out whether the investigational drug has a useful clinical effect and what its safety profile is. You can click here to see an example of a trial like this, where the investigational drug ZD4054 is being compared to placebo in patients with non-metastatic, hormone-refractory prostate cancer.
  • In the very best clinical trials you will be randomized to one of two arms: the current standard therapy (e.g., docetaxel + prednisone for treatment of hormone-refractory prostate cancer) or a new therapy that is under investigation for exactly the same clinical indication (e.g., docetaxel + prednisone + atrasentan). This specific Phase III trial is described in detail on the web site. Atrasentan is a drug that is not yet available for the treatment of any disease outside a clinical trial.
  • In early stage trials of new therapies, you may definitely get the study drug, but less will be known about the risks involved in taking the drug, so you may find you have side effects that were not predicted. An example of such a study is the Phase II trial of TPI 287 in patients with metastatic prostate cancer. Like atrasentan (see above), TPI 287 is an investigational drug that is not available for treatment of any disease outside a clinical trial.
  • There is enormous variation in how people respond to some types of drugs. This can lead to some real issues. Here is one that is becoming more of a problem as we develop new drugs with sophisticated mechanisms of action. What happens is that the drug doesn’t seem to work in most of the people in the trial, but it does seem to work in a subset of those patients. So now there isn’t enough information for the drug to be approved (unless a very sophisticated subset analysis was built into the trial protocol from the very beginning). If you are one of the small subset of patients on whom the drug seems to work, however, you are NOT going to be a happy camper! (This is what may have happened in the case of a drug called Provenge mentioned elsewhere.) 
  • Clinical trials of agents to prevent development of prostate cancer tend to go on for a very long time. It also may take years and years before the results are available. If you think you want to participate in one of these trials, that’s great, but bear in mind that you can’t expect any results in a big hurry! Here’s a link to an example of a small trial of this type being carried out at just three centers that won’t provide even preliminary results before 2012.

There are literally hundreds of other issues that may impact your decision to participate in any specific clinical trial. And you really do need to think and learn about all the issues. However, The “New” Prostate Cancer InfoLink encourages all patients with prostate cancer or at risk for prostate cancer to consider participating in clinical trials when it seems appropriate, not just for their own benefit but for the potential benefit of every other prostate cancer patient who is going to follow them.

Content on this page last reviewed and updated April 6, 2008.
%d bloggers like this: