Frequently Asked Questions
Learn the basics about clinical trials
Learn the answers to the most frequently asked questions about the clinical trial process including what happens during the trial, the research conducted, participation, and more.
FAQs
Overview
Clinical trials are the best way to study new, investigational treatments or vaccines to learn if they work and how safe they are. If you have ever taken medicine or gotten a vaccine, then you have benefited from clinical trials.
Trials often try to answer specific health questions, like if a new treatment has any effect, if it could work better than an existing treatment, or if it’s safe for people to use. Some of these treatments have not been approved by a government agency, which is why they are called “investigational” treatments. If clinical trials show that a new treatment works and is safe, then it can be approved to be used by the people who need it.
Clinical trials are the best way to find out if new treatments or vaccines work and how safe they are. If clinical trials show that a new treatment works and is safe, then it can be approved to be used by the people who need it.
Clinical trials have led to a lot of important medical discoveries that help researchers find better ways to diagnose, prevent, and treat diseases. These medical discoveries can help people to live healthier, longer lives.
Clinical trials answer questions such as:
- Is a new drug or device safe?
- Is a new treatment better than existing treatments?
- Can a treatment help people with cancer?
- Does a treatment improve patients’ quality of life?
- What is the best way to use a treatment?
Each trial needs participants who meet certain requirements, like having a certain disease or medical condition. These requirements are called inclusion criteria. Other inclusion criteria include age, sex, body type, and current treatment plan.
Some trials might have rules that prevent a person from being in a trial. These rules are in place to protect people whose conditions might get worse if they were in the trial. These rules are called exclusion criteria.
Inclusion and exclusion criteria are in place to make sure the researchers get the most accurate results. They also help make trials as safe as possible.
Not all clinical trials test a new treatment or vaccine. “Observational” studies collect information about people’s health during their normal care. This helps researchers learn more about specific health issues.
Yes, children can be in clinical trials when the researchers want to know if a treatment works for participants 18 or younger. The child’s parent or guardian must give permission for the child to participate.
Pediatric clinical trials are important because they allow researchers to:
- Study a treatment in children that is already approved for adults
- Find new treatments
- Improve and compare existing treatments
- Find the right dose for children
Pediatric clinical trials are needed because children’s bodies work in different ways than adults, and they go through many changes as they grow.
If you are thinking about allowing your child to participate in a clinical trial, see our Should My Child Participate brochure for more information about whether joining a clinical trial is best for your child.
It is important to make an informed decision before deciding to join a trial. Making an informed decision means that you have learned as much as you can about a clinical trial to make a choice that is best for you.
Participating in a clinical trial can affect your life. It is okay to take your time with the informed decision process. Comparing the potential risks and benefits is the most important part of deciding whether to be in a trial. Doing this can help you decide if being in the trial is right for you. The potential benefits and risks of every trial are different. Gather as much information as you need to make a decision that you feel good about. There is no right or wrong choice.
See our Should I Participate brochure for more information on how to make the best decision for yourself and your loved ones.
What Happens in Clinical Trials?
If you agree to participate in a clinical trial, you might receive a trial treatment or something else, such as a placebo, which looks or tastes like a treatment but does not have any actual treatment in it. You also might get a treatment that is already approved for public use.
Participants do not get to choose which treatment they get, and the treatment each participant gets is usually decided randomly. The treatment may be given as a pill, injection, infusion, or in other ways.
In some trials, you might only give permission for researchers to collect health information through surveys or medical records. Some clinical trials include “healthy” participants, who do not have the condition the trial is studying.
You may need to visit the trial site for tests and treatment and for doctors to check on your health. These visits can also be at your home or through telemedicine.
A placebo looks like a treatment but does not have any medicine in it. Researchers use placebos to help make sure any changes in the participants’ health are actually caused by the trial treatment. You do not get to choose if you get the trial treatment or the placebo, and you may not know if you get the placebo until after the trial. Not all trials use a placebo.
A participant who gets the placebo might suddenly feel better because they thought they got a real treatment. This is known as the placebo effect. Researchers compare the results of participants who took the placebo with the results of participants who took the trial treatment. This helps them learn how the trial treatment works and if it’s safe.
Usually, the participants do not know that they are taking the placebo. Sometimes the doctors also don’t know, which helps them treat each participant the same.
Trials can last weeks, months, or even years. The number of visits and how long you may be in the trial overall can be different for every trial. You may need to visit the trial site for tests and treatment, and for doctors to check on your health. These visits can also be at your home or through telemedicine.
There is a lot of preparation that takes place before a trial starts, and trials need more review after all the participants have left. It can take many years before a treatment is approved and ready to be used by the public.
Participants can leave a trial at any time and for any reason.
All clinical trials must follow federal laws and ethical guidelines. Trials must also be approved by an expert group called an institutional review board (IRB) that helps make sure the trial is fair and as safe as possible, and that any risks to the participants are worth the potential benefits.
Every trial must also have a protocol, which is the overall plan for the trial that includes instructions that the doctors and staff doing the trial must follow. This protocol must be approved by an IRB.
You can take as much time as you need before deciding. It is very important to understand a clinical trial and to be comfortable with what is planned to happen before you agree to participate.
Being in a trial is optional. Agreeing to be in a trial does not take away any of your rights. You can stop being in a trial at any time and for any reason. The trial staff will help you do this safely. You can talk to the trial staff or the IRB anytime you have concerns about being harmed.
It’s very important to understand a trial before joining. Researchers are not allowed to give you treatment in a trial unless you fully understand what is going to happen.
Every clinical trial has a process where the trial doctor and research team go over what happens in the trial and reasons you may or may not want to join. The trial doctors and research team will explain what treatments you might get, how long the trial is expected to last, what happens during visits, the potential risks and benefits, and many other important facts about the trial. This process is known as informed consent.
You must read and agree to an Informed Consent Form before you participate. You will get a copy of this form. As a potential participant, you can ask as many questions as you want before signing the Informed Consent Form.
Yes. Being in a trial is optional. You can stop being in a trial at any time and for any reason. The trial staff will help you do this safely.
Yes. Participants should still see their primary care doctor to make sure they get all the usual treatments they need. Primary care doctors can work with the research team to make sure that a participant can keep taking their other treatments.
No. Standard of care is treatment that has already been tested and approved by the government. In other words, doctors know how a standard of care treatment works. The trial treatment in any trial is still being tested, so doctors and researchers don’t know enough about how it works or how safe it is yet.
Clinical Trial Research
If you agree to participate in a clinical trial, you might receive a trial treatment or something else, such as a placebo, which looks or tastes like a treatment but does not have any actual treatment in it. You also might get a treatment that is already approved for public use.
Participants do not get to choose which treatment they get, and the treatment each participant gets is usually decided randomly. The treatment may be given as a pill, injection, infusion, or in other ways.
In some trials, you might only give permission for researchers to collect health information through surveys or medical records. Some clinical trials include “healthy” participants, who do not have the condition the trial is studying.
You may need to visit the trial site for tests and treatment and for doctors to check on your health. These visits can also be at your home or through telemedicine.
If trials do not include diverse participants, we cannot know if treatments work for everyone who needs them. Trials only tell researchers how something works for the participants of that trial. Treatments and vaccines might not work the same in people of different races, ethnicities, ages, or sexes.
There are many different types of trials:
- Treatment trials test new treatments, new combinations of treatments, or new approaches to procedures.
- Prevention trials look for better ways to prevent disease in people who have never had the disease, or ways to prevent a disease from returning.
- Diagnostic trials find better tests or procedures for diagnosing a particular disease or condition.
- Screening trials test the best way to detect certain diseases or health conditions.
- Quality of life trials explore ways to improve comfort and the quality of life for individuals with chronic illness.
Clinical trials have four phases. The trials have different purposes at each phase and help scientists answer different questions:
- Phase 1: Researchers test a new treatment in small groups of participants to learn how safe it is and how much people can safely take. They also sometimes want to learn how the treatment works in the body.
- Phase 2: The trial treatment is given to larger groups of people to learn how well the treatment works and more about how safe it is.
- Phase 3: The trial treatment is given to even larger groups of people to confirm how the treatment works and learn even more about its safety. Researchers often compare it to other treatments that exist, or a placebo.
- Phase 4: At this phase, the treatment has been approved by a government agency to be used by the public. Phase 4 trials aim to learn more about the risks and benefits of a treatment, as well as the best way to use it.
In every phase, researchers also want to learn about any medical problems the participants have.
Phase 1 and 2 trials are usually shorter than Phase 3 and 4 trials. If the researchers in any phase think that a treatment does not work, they might not do any more clinical trials for that treatment.
Before I Participate…
It is extremely important to understand a trial before you agree to participate. Plan ahead by making a list of questions to ask the research team. Talk to family, friends, counselors, and other people you trust. Talking to people with different views and information can also help. You can ask a friend or family member to come along for support and to help you understand the trial.
See below for important questions to consider.
Every clinical trial is different. You should ask as many questions as you need until you fully understand what to expect in a trial. Here are some examples:
Questions to Ask Yourself
- Do I want to participate? Why or why not?
- Does participating fit with my values, beliefs, and preferences?
- What would I like to get out of participating?
- What amount of risk am I willing to take? Do the possible benefits outweigh the risks?
- Do I have enough time to participate?
- Would I need to arrange for child care or for the care of another family member if I participate?
Questions to Ask a Healthcare Professional
- What are the possible risks and benefits of participating?
- How would the risks and benefits of a trial treatment compare with my current treatment?
- How might participating affect my daily life?
- Would I have to pay for any part of a clinical trial? Will my insurance cover these costs?
- What are the current treatment options for my condition?
- Are there any clinical trials that would be a good option for treatment?
- Can I get the materials in a language I want? Can I get a translator?
- Will you be part of my care team if I participate in a clinical trial?
Questions to Ask Family, Friends, and Others You Trust
- Can you attend doctor visits with me to help make sure I understand everything?
- Can you take notes and help me organize the information I get during doctor visits?
- Would you be able to watch my kids, pets, or house while I go to appointments?
- Would you be able to give me a ride if I need it?
- What do you think about me participating in a clinical trial?
- What do you think about clinical trials in general?
Ask questions until you feel comfortable. Once you have asked all your questions and have all the information you need, you might want to make a list of pros and cons. This can help you make an informed decision about participating in clinical research.
Some potential risks if you participate are:
- The treatment in the trial may not help you.
- You may have side effects from the trial treatment.
- You may have frequent testing or blood draws.
- You may need to set aside time for participation.
Some potential benefits if you participate are:
- You will help researchers learn more about how a treatment affects your community.
- You may have early access to advanced treatments for your condition.
- You may have access to treatment when no approved treatment exists.
- Your health will be watched by the trial doctors and nurses.
Some trials pay for travel costs, time, and commitment. But not all do. Each trial will have its own guidelines that tell you if you will be paid and what costs will be covered. Check with your trial doctor and the research team to confirm.
Payments in trials are made for your time and possible inconvenience of participating in the trial. These payments are also called compensation or stipends. The amount is usually based on the trial length, number of visits, the types of procedures, and other factors.
See our Guide to Costs and Payments in Clinical Trials brochure for more details on payments.
Some costs may be covered by your health insurance. These may include travel costs for taxis, buses, gas mileage, or hotels. There could also be costs for the care you receive in a trial.
Usually, most of the costs in a trial are covered by the trial sponsor. The sponsor is the organization that funds and conducts the trial. Every trial has an Informed Consent Form that explains the possible costs, payments you may receive, and expenses that will be covered by the sponsor. You can also ask the trial staff for more information about costs.
You have the right to communicate with the clinical trial staff in the language that is most comfortable for you. You can ask for an interpreter, or for a doctor or community health worker who speaks the language of your choice. You can also request any documents in the language of your choice.
Where Can I Learn More About Joining a Clinical Trial?
If you have a specific condition, the patient advocacy organization for your condition may have a list of clinical trials. Your doctor may also know about clinical trials for your condition. If you would like to learn more about current clinical trials, call 1-877-MED-HERO.
The website https://www.clinicaltrials.gov/ is run by the National Institutes of Health (NIH). It provides education about clinical trials and lists many of the open and recruiting trials taking place in the United States in both English and Spanish.
If you are ready to find trials in your area, CISCRP’s free service will provide a list of relevant trials. Go to https://www.ciscrp.org/services/search-clinical-trials/ or call 1-877-MED-HERO.
Always talk to your trusted doctors, family, and friends before making a decision about joining.
You can find results from past clinical trials on the website https://www.clinicaltrials.gov/. Some sponsors post results on their own websites. The European Union (EU) also posts plain language summaries for trials that take place in any EU member state. You can search for these summaries on this website: https://euclinicaltrials.eu/search-for-clinical-trials.
As a participant, you are entitled to a plain language summary of the results of your clinical trial once the trial is finished. CISCRP works with research sponsors to make these summaries. If you do not have access to a summary, check with the trial doctor or research team.
Glossary
CISCRP is proud to collaborate with the Multi-regional Clinical Trials Center (MRCT) on a plain language glossary for clinical research terms. This glossary is being developed by a group of experts and patient advocates in different countries.
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Learn more about clinical trials through our videos, medical hero stories, & brochures.
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Additional Clinical Trial Resources
For more information about Expanded Access in the USA, please visit FDA’s educational page. For European readers, please visit EMA’s page. Additional information about clinical studies, visit www.clinicaltrials.gov/ct2/about-studies/learn
The above information is provided by clinicaltrials.gov, a service of the National Institute of Health.
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