Clinical Trials: What You Need to Know

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What’s It Like to Be in a Clinical Trial?

Having an idea of what you can expect if you take part in a clinical trial can help relieve some of your concerns. Here’s an overview of what might happen.

Informed consent or informed permission

The first thing you’ll need to do is give your informed consent to take part in the clinical trial.

The people running the clinical trial must get your written, informed consent before you take part in any way – even before you have any tests done to see if you’re eligible for the study. In the informed consent process, the researchers (doctors or nurses) will explain the details of the study to you and answer your questions and concerns. If you’re looking at a study for your child, this process is very much the same but may be called informed permission.

You will then be given a written consent form to sign. Parents must sign the form for their child, and in most cases older children must also agree before they take part. (This is called assent.) In general, these children’s rights are very much like those of adults, including the right to leave the study anytime they want. Consent forms are not all the same, but they should include the following:

  • The reason for the study (what the researchers hope to find out)
  • Who is eligible to take part in the study
  • What’s known about the new type of treatment
  • The possible risks and benefits of the new treatment (based on what’s known so far)
  • Other treatments that may be an option for you
  • The design of the study (whether it’s randomized, double blinded, etc.)
  • How many and what types of tests and doctor’s visits are involved
  • Who must pay for the costs of the clinical trial (tests, doctor’s visits, etc.) and for the costs if you need extra care as a result of the clinical trial
  • A statement about how your identity will be protected
  • A statement about the voluntary nature of the study and your right to leave the study at any time without fear of affecting the care that you would normally get outside the study
  • Contact information in case you have questions at any time before and during the study

Before you sign the consent form, ask questions. Be sure someone from the research team goes over the form with you. Consent forms are not all easy to understand, and there may be words or ideas that seem confusing. You may want to bring someone along with you to help make sure all your concerns are addressed.

Be sure you understand what’s involved and what’s expected of you. Review what you understand about the study with your doctor or nurse to make sure you’ve got it right.

Finally, don’t feel rushed into making a decision. Take the consent form home with you if you need to. Ask trusted family members and friends what they think. Some people may want to get a second opinion about the study from another doctor, too.

Taking part in the study

Once you’ve signed the consent form, you’ll be ready to take part in the study. You’ll probably need to have blood tests and/or imaging tests done before you start treatment (if you haven’t had them recently). A full medical history is taken and a physical exam is usually done. These are needed before you start the study to be sure that you meet the eligibility criteria and to help ensure your safety.

As mentioned earlier, the participants are often treated much the same way as other patients who aren’t in a clinical trial.

You may have tests done more often to find out how well the treatment is going and to look at how you’re doing. You’ll likely get more attention as a study participant than you would otherwise. The doctors and nurses may examine you more often and will want to know if you’re having any side effects (called adverse events) while being treated.

Because the possible complications may not fully be known, it’s very important to let the research team know about anything out of the ordinary. They can then decide if symptoms you’re having are related to the study, and if they need to be treated or your treatment needs to be changed.

What if I want to leave the study early?

You will be told many times before you enter the study that taking part in the study is always voluntary. This is an important point. You (or your child) have the right to leave the study at any time, for any reason. Your doctor will still take care of you to the best of his or her ability.

You may quit taking part in the study at any time and for any number of reasons:

  • You complete treatment on the study
  • The treatment doesn’t seem to be working for you
  • You have serious side effects while in the study
  • The study itself is stopped early because the treatment either has proven to work, has proven to not work as well as the standard treatment, or has been found to be too harmful
  • You decide to leave the study

No matter when or why you leave the study, the researchers may ask to follow up with you from time to time to see how you are doing. This can give them important information and can also help ensure your safety, even though you’re no longer part of the study.

What if I’m not eligible for a clinical trial?

Some people may be too sick or have other problems that keep them from taking part in clinical trials, but most people will probably be eligible for some type of study. This is true even if they’ve had many different treatments already.

Some people may be interested in a certain treatment that’s only available in clinical trials, but they don’t meet the eligibility criteria outlined for the studies. In some of these cases, a person’s doctor may ask the study sponsor if they can get an eligibility waiver or special exception to allow the person into the study, even though they don’t meet all of the criteria. This decision is usually made by the study’s clinical investigator, who may consult with others involved in the study about the request. If entered in the study, the person is treated according to the study protocol (the same tests, doctor’s visits, follow-up, etc.), but the results from that person are not included in the final study results.

In some cases, studies may have already enrolled enough people and aren’t taking any more participants.

Sometimes, there are ways to get access to treatments that are in late phase clinical trials but not yet approved by the FDA. These are usually referred to as expanded access or compassionate use programs. In recent years the FDA has broadened these programs to allow some patients who urgently need these treatments to be able to get them. For more, see Compassionate Drug Use.


Center for Information and Study on Clinical Research Participation. 2015 Perceptions & Insights Study: Report on Participation Experiences. Accessed at on May 5, 2016.

Centers for Medicare & Medicaid Services. Clinical research studies. Accessed at on May 3, 2016.

Friedman LM, Furberg CD, DeMets DL. Fundamentals of Clinical Trials, 4th ed. 2010. New York, NY: Springer Science + Business Media, LLC.

National Cancer Institute. Patient Safety in Clinical Trials. Accessed at on May 3, 2016.

Stryker JE, Wray RJ, Emmons KM, Winer E, Demetri G. Understanding the decisions of cancer clinical trial participants to enter research studies: factors associated with informed consent, patient satisfaction, and decisional regret. Patient Educ Couns. 2006;63(1-2):104-109.

Last Medical Review: 05/03/2016
Last Revised: 05/03/2016