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Cancer Mythbusters: Cancer Clinical Trials

  • Clinical trials are scientific studies in which new treatments are testing to determine if they are safe and effective for patients. But what does it mean for a patient to enroll in a clinical trial? We break down common myths and questions about how these trials work with the help of Geoffrey Shapiro, MD, PhD, director of the Early Drug Development Center at Dana-Farber.

    Read the transcript:

    MEGAN: Hi, I'm Megan Riesz, and this is Cancer Mythbusters, a podcast from Dana-Farber Cancer Institute about the many myths and misconceptions in the world of cancer. Every episode, we'll take a look at a myth and debunk it with the help of our world-leading clinicians and researchers.

    Better cancer treatment depends on clinical trials for new drugs and other therapies.

    Clinical trials help determine whether new treatments are safe and effective. In fact, nearly all cancer drugs in use today were tested and made available to patients through these studies.

    But clinical trials can be hard to understand.

    Just the descriptions of them can be confusing, and the word "trial" can make you wonder if the success of your treatment is up to the flip of a coin, which leads us to today's big question: Does a cancer patient have a good chance of getting a placebo if they enroll in a cancer clinical trial? And if not, what can patients really expect if they decide that a clinical trial is right for them?

    To set the story straight, I sat down with Dr. Geoff Shapiro, Director of the Early Drug Development Center at Dana-Farber, which specializes in conducting Phase I clinical trials.

    MEGAN: Thanks for joining me, Dr. Shapiro.

    DR. SHAPIRO: I'm happy to be here. Thanks for having me.

    MEGAN: To start this off, let's go over some basics. Who can participate in a clinical trial? And how does it ensure that patients are safe during clinical trials?

    DR. SHAPIRO: As we're trying to make cancer treatments better and develop new cancer treatments, we like to try to offer clinical trials to as many patients as possible. Many, many patients who have active cancer are eligible to participate in clinical trials. Each clinical trial, however, will have some eligibility criteria that need to be met, and in general, patients have to be relatively well, have good organ function (such as their kidneys, liver, and bone marrow).

    In clinical trials, especially those that involve brand-new drugs, patients are monitored very carefully. This is a lot of courageous volunteerism on the patients who participate, and that requires many, many clinic visits so that we can monitor things very, very closely. The very close follow-up is what ensures that the patients are safe during studies. The risk of very severe side effects or of even dying on a clinical trial a really very, very small, and this is because we follow patients so closely.

    MEGAN: Many people think that if they go on a clinical trial, they may not get a real treatment, or they may get a placebo. What's the deal here?

    DR. SHAPIRO: That's an unusual situation where we would use a placebo. There's Phase I clinical trials, where it's really a brand-new drug or a brand-new drug combination. Those trials are designed to establish:

    • What is the right dose for the drug or drug combination?
    • What is the safety profile?
    • If there are no bad side effects, we then can increase the dose in each subsequent group of patients who are enrolled.

    In a Phase I trial, everyone gets the study drug. There's never any placebo. Whether it's a drug being used alone or a new drug combination, everyone is getting the study treatment. If a drug does well in Phase I, it then moves into Phase II.

    A Phase II study is a disease-specific study. That will say, "Now we have Drug X. We now know the right dose and the side effect profile," and we'll ask, "How do 50 people with breast cancer do with this drug?" Everybody on a Phase II study is getting the same dose and schedule. We know the expected side effect profile. A Phase II study is designed more to assess how well the drug works in that specific population, and in general, for Phase II studies, everyone is getting the study treatment as well. If a drug does well in Phase II, it then will graduate to what's called Phase III.

    In a Phase III study, that is a comparison study. That would be taking the new treatment and comparing it to either a standard treatment or, in some cases, to a placebo when it's appropriate to be evaluating a placebo.

    In the majority of studies that are done in this day and age, use of placebo is uncommon. Typically, new drugs would be compared to a standard treatment so that, in the majority of cases, patients are receiving active treatment for their cancer.

    MEGAN: How are those rare clinical trials that use placebos designed to ensure that patients still receive the best treatment available?

    DR. SHAPIRO: Trials that would use a placebo would be when there really is no standard treatment. For example, the drug Tarceva, which is a drug used in lung cancer, when that drug was first developed, it was being tested in lung cancer patients who had already exhausted all of the standard treatments. In that particular case, the original trials of Tarceva compared patients who would get Tarceva to a placebo pill. Really, the placebo would be used when there is no good active treatment for the patient.

    MEGAN: What kind of questions should a patient ask their doctor to ensure that they are enrolling in the right trial for them?

    DR. SHAPIRO: I think that it's very important that patients talk to their doctors about what the standard treatments are that are available and what those treatments can accomplish. If the treatments are not curative, or the expectations from the standard treatment would be very limited in scope, then I think it's appropriate to determine whether there's a clinical trial that may be helpful. In this day and age, clinical trials are often matched to the tumor profile, so I think it's very important that patients ask their doctors about what happened on their tumor profiling test, what alterations have been found in the tumor, and what clinical trial drugs might be available that address those alterations.

    I think that also patients need to consider the research requirements that are involved in clinical trials, and they need to talk to their doctors about that. Many clinical trials are much more complicated than standard treatment because we're following patients so closely, and patients require many, many clinic visits. These types of things can impact on a patient's quality of life, and all of these things go into the decision about whether a clinical trial is right for a patient.

    MEGAN: Do patients who are already enrolled in standard therapy have to stop that therapy to enroll in a clinical trial?

    DR. SHAPIRO: Usually, yes. Usually, a clinical trial that's involving a new drug or a combination of standard with a new drug, yes, you would have to come off the treatment that you're on. There's usually a brief rest period, called a "washout period," and then you can enroll on the trial that involves the new study drug. That is one thing that has to go into the decision-making process, whether people are willing to stop that standard therapy and whether it's the right thing to do to stop that standard therapy in order to enroll in a study.

    MEGAN: What are some resources that you would recommend for finding potential clinical trials? Should patients seek out trials themselves? Or should they wait for their doctors to suggest one?

    DR. SHAPIRO: This is a complicated business just because of the explosion of new cancer drugs and the number of clinical trials available. Many patients do try to seek these things out themselves, and there are resources that are available, such as ClinicalTrials.gov. One can search for disease types or for specific drugs and find out what trials might be available on that particular website.

    Often, I think that patients can do some research on their own, but it really also then has to be something that is fleshed out with the primary oncologist, or with investigators doing the trials, to figure out whether those trials are really the right things to do and which ones make the most sense.

    MEGAN: Thank you so much for joining us, Dr. Shapiro.

    DR. SHAPIRO: All right. Well, I hope that's been helpful!

    MEGAN: So, myth busted — patients do not receive placebos in clinical trials, except for in rare circumstances. Usually, in clinical trials, the drug that is being tested is compared to a standard treatment that is already available, so in the majority of cases, patients do receive active treatment for their cancer. In trials that would use placebos, there really is no effective standard treatment available for the patient that the clinical trial treatment could be compared to.

    If you have questions about clinical trials, talk to your primary physician.

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