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This is Your Brain on DrugsClinical Trials: What You Need to KnowClinical trials are research studies with clearly defined goals. Not all clinical trials are designed to develop new treatments. Some are designed to evaluate the characteristics of drugs; some collect tissue for research in a laboratory; some are "feasibility studies" that determine whether a much larger clinical trial should be launched. It is important to understand that a clinical trial may not be of benefit to an individual patient, but may provide clues for further research in the future. There are some excellent websites, many hosted by research organizations or hospitals, that discuss the role of clinical trials in the treatment of cancer. Several are listed at the conclusion of this article. Some, such as virtualtrials.com, include other information, such as national news about brain tumor treatments. However, some patients are still very confused about their treatment options. The following example is typical of the discussion between doctor and patient regarding treatment options on a clinical trial -- Doctor: Mrs. Jones, as you recall from our last visit, we were discussing the various options for your therapy and you were interested in clinical trials. You had mentioned that your family had found a number of different clinical trials on the Internet. Would you like to discuss what you've found?
Doctor: The first thing to do is to define which treatments are designed for your disease, glioblastoma multiforme. In some treatment protocols, glioblastoma is called malignant glioma or high grade astrocytoma, and those words are often in the title. You've had surgery, but have not yet had radiation therapy. Since you're newly diagnosed, you can eliminate all the clinical trials referring to recurrent tumors. Mrs. Jones: That still leaves dozens of different treatments. How do I know which treatments I'm eligible for?
Mrs. Jones: Are there are clinical trials available around here or will I have to travel? Doctor: There are trials available in the Dallas-Fort Worth area and in other research centers in San Antonio and M.D. Anderson in Houston. First you should find out all you can about the trial and the research organization hosting the trial. Only you can decide whether it is reasonable to receive your care there. There are also research centers around the country, if you are willing to travel out of state.
Doctor: Phase I trials are the first studies done in a drug's development. If a new drug looks promising in animal studies, a Phase I study determines the safe dose that can be given in humans. Some Phase I studies will treat all types of cancer, and some are restricted to brain tumor patients only. If you enter the study at the beginning, you could receive a very low dose of the drug. As more patients enter the study, the doses are increased until the physicians monitoring the trial note the side effects of the drug. If the side effects are intolerable for the patients at that dose, the dose just lower than that will probably be the final dose recommendation for the drug. Mrs. Jones: That sounds as the dose may be too high or too low to do me any good. Doctor: That's exactly right. Since the purpose of the trial is to define the dose of the drug that causes side effects, and determines what side effects there are, there may be no effect on the growth of your tumor. Statistically, only a few patients have any regression of their tumor while treated on a Phase I trial. A Phase II study, however, determines whether the dose determined from the Phase I trial is actually effective. In your case, since you have had a complete resection of your tumor, you may not be eligible for a Phase II study.
Doctor: To determine whether the drug is working, it is important to see some visible tumor on an MRI scan which can then be followed in the future to see if it regresses. It is important to remember that the purpose of the Phase II study is to determine whether the drug is effective. It may not be. It may be less effective than standard therapy, which in your case would be radiation therapy and BCNU. Mrs. Jones: Would a Phase III trial be better for me? Doctor: A Phase III trial randomizes patients to two or more different kinds of therapy. There may be one group of patients receiving BCNU, for example, and one group receiving a new drug, and another receiving the combination of BCNU and the new drug. Patients can also be randomized to receive a new drug or to receive a placebo. Mrs. Jones: There is no way to determine in advance which treatment I will receive? Doctor: No. In some cases, in trials in which a placebo is used, neither the doctor nor the patient knows whether the patient is taking the placebo, which is usually identical to the appearance of the new drug. Mrs. Jones: But if I were going to participate in a trial, I would want to know that my treatment is going to be more effective than if I had standard therapy. Doctor: There is no way that the physicians designing a clinical trial can guarantee that you will do better on the trial than if you did not participate. On some Phase II trials, if many patients have already been successfully treated, you may feel more comfortable with the decision to participate. However, there are also large number of studies that are "negative," meaning that an overall improvement in survival for the entire group of patients was not achieved. If a new drug was clearly showing an improvement in survival for an entire group of patients over standard care, it would quickly become the new standard of care. Mrs. Jones: So you're not recommending that I consider a clinical trial? Doctor: On the contrary! It is very important that all cancer patients consider participation in clinical trials because all promising new treatments must be evaluated thoroughly before they can be become more widely available. There is simply no progress made without clinical trials. The Phase I, Phase II, and Phase III studies are very logical, scientifically valid ways to establish whether a treatment that looked effective in animal studies is equally effective in humans. Mrs. Jones: I'm not sure I want to participate, but I still want to consider participating in the future. What should I do? Doctor: It is important to look carefully now at any clinical trials in which you might want to participate in the future. There are some trials that you must enter before radiation therapy, some that do not allow previous chemotherapy, and some that require a re-operation. Once you begin radiation therapy, you cannot interrupt it to enter a clinical trial. Keep a folder of trials that you think are particularly interesting, and we can contact the facility hosting the trial. Some organizations list all of their current trials on their website. Mrs. Jones: It looks as I have a lot of work to do before I can make a decision. Doctor: Fortunately, there are several websites available that are easy to use. I'll give you a few days to check though your list, and can arrange for your radiation therapy if that's what you choose to do first. If you have any questions, don't hesitate to call. |
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Mrs.
Jones: I've found hundreds of different
treatments, but it's very hard to decide what's right for me. How do I make
sense out of this?
Doctor:
All clinical trials will have some
eligibility criteria and specifically, what treatments you are allowed to have
prior to participating. For example, you have not been treated with radiation
therapy, and some trials require that you have completed radiation therapy
before you can go on their study. Other protocols require that you have had a
complete surgical resection, removing all the visible tumor. If you do not meet
every criteria specified in the protocol, most institutions will not allow you
to participate.
Mrs.
Jones: What is the difference between a
Phase I, Phase II, and Phase III trial?
Mrs.
Jones: Why is that?