What is a Clinical Trial?

New to Learning about Clinical Trials?

Considering Trial Participation?

Specific Trial Information

What is a clinical trial? (see the "Introductory" video for more information)

Clinical trials are research studies in humans designed to study if an experimental therapy or treatment works. Clinical trials are the final step in a long process that begins with research in a lab. Much of what we know about disease progression and effective therapies and treatments used today are the result of past clinical trials. Clinical trials can be used to determine: 

  • whether a treatment is safe
  • how well new experimental therapies/treatments work in particular people


Why participate in a clinical trial? (see "Benefits" video for more information)

Participants in clinical trials can play a more active role in their own health care, gain access to new research treatments before they are widely available, and help others by contributing to medical research. 

Who can participate in a clinical trial? (see "Trial Criteria" video for more information)

Each study has rules about who can or cannot be in the study. These rules are called eligiblity criteria and they describe features that must be shared by all the people in the study. The eligibility criteria, also called the inclusion and exclusion criteria, differ from study to study. "Inclusion criteria"  help make sure everyone in the trial is as similar as possible. This helps researchers understand the results from the study better since there will be fewer differences between people in the study. The "exclusion criteria" help keep people safe by excluding those from the trial that may be especially at risk if they were in the study.  

Before joining a clinical trial, a participant must go through a screening process with the study team to see if they meet the eligibility criteria. Some research studies seek participants with illnesses or conditions to be studied in the clinical trial, while others need healthy participants. It is important to note that inclusion and exclusion criteria are not used to reject people personally. Instead, the criteria are used to identify appropriate participants and keep them safe. The criteria help ensure that researchers will be able to answer the questions they plan to study.

What happens during a clinical trial?

The clinical trial process depends on the kind of trial being conducted (see "types of clinical trials"). The clinical trial team includes doctors and nurses as well as social workers and other health care professionals. They check the health of the participant at the beginning of the trial, give specific instructions for participating in the trial, monitor the participant carefully during the trial, and stay in touch after the trial is completed.

Some clinical trials involve more tests and doctor visits than the participant would normally have for an illness or condition. For all types of trials, the participant works with a research team. Clinical trial participation is most successful when the protocol is carefully followed and there is frequent contact with the research staff.

What is informed consent?

Informed consent is a process. The process involves learning key facts about a clinical trial by listening and asking questions of the study team and other professionals before deciding whether or not to participate. 

This process should continue throughout the study to provide as much information for participants as possible. The informed consent process is meant to help people to understand the study goals, process, risks and benefits. When you first meet with the study team they will provide you with information and give you a chance to ask questions. Then the research team provides an informed consent document that includes details about the study, such as its purpose, duration, required procedures, and key contacts. Risks and potential benefits are explained in the informed consent document. The participant then decides whether or not to sign the document. Informed consent is not a contract, and the participant may withdraw from the trial at any time.  


Things to keep in mind:

  • You don't have to sign the consent form on that day.  You can take it home to review it with your family and with your doctor.
  • You should sign a consent form before you do any study assessments.
  • If your child is participating, and he or she is 7 years old or older, the study team may ask your child to sign an assent form. The assent form has similar information as the consent form, but it is explained in easier terms. As a parent, you can use the assent form to help your child understand the purpose of the study and what will happen during the study.
  • Even after you sign the consent form, you do not have to participate in the study. You can quit at any time. Although, in some studies the team may ask you to do some follow-up visits to monitor your child's health.


What are the benefits and risks of participating in a clinical trial?

Each clinical trial offers its own potential benefits and risks but most have some things in common.

Benefits (see the "Benefits" video for more information)
Being in a clinical trial can allow a person to:

  • Play an active role in their own health care.
  • Gain access to new research treatments before they are widely available.
  • Obtain expert medical care at leading health care facilities during the trial.
  • Help others by contributing to medical research.


Risks (see the "Risks" video for more information)
Clinical trials are experiments and each trial has its owns risks. Some potential risks are:

  • There may be unpleasant, serious or even life-threatening side effects to experimental treatment.
  • The experimental treatment may not be effective for everyone.
  • The protocol, or study plan, may require more of your time and attention including trips to the study site, more treatments, hospital stays, etc.
  • Being in a trial can be emotionally difficult.


What are the side effects and adverse reactions? (see the "Risks" video for more information)

Side effects are any undesired actions or effects of the experimental drug or treatment. Experimental treatments must be studied for both immediate and long-term side effects.


How is the safety and privacy of the participant protected?

There are many things that the study team does to protect the safety, privacy and confidentiality of everyone in the study. This includes identifying people in the study by number, rather than name, in the study databases to help protect privacy. This practice is called de-identification. If anything serious goes wrong during a study, the researchers have to tell the Institutional Review Board (IRB) to help protect the participant's safety. The IRB can stop a study if the researchers are not following the study protocol, or if the trial is causing unexpected harm to people, or if the new treatment is obviously working (so that the treatment can be made available to everyone). (see the "Trial Failures" video for more information)

Some clinical trials, especially phase III trials, use a Data and Safety Monitoring Board (DSMB). A DSMB is an independent group made up of statisticians, doctors, and patient advocates. The DSMB tries to make sure the study risks are as small as possible, that the study data is complete, and that a trial is stopped if there are concerns about safety.


Who sponsors clinical trials? 

Clinical trials can be sponsored or funded by a variety of groups or individuals. These include doctors, medical institutions, foundations, voluntary/support groups, pharmaceutical companies and federal agencies (like the National Institues of Health (NIH) or the Department of Defense (DOD)).  Clinical trials can take place in different locations, but often take place at hospitals, universities, doctors' offices or community clinics. 


How do I find out about clinical trials? (see the "Information" video to hear from families on how they gather information about clinical trials)

You can find information about clinical trials many different ways such as: