A clinical trial is a research study in human volunteers to answer specific health questions. Carefully conducted clinical trials are the safest and fastest way to find treatments that work in people, and new ways to improve health.
There are different kinds of clinical trials, including those to study:
new treatments or new ways to use existing treatments
new screening and diagnostic techniques
options for improving the quality of life for people who have serious medical conditions
Clinical trials are conducted according to a plan called a protocol. The protocol describes what types of patients may enter the study, schedules of tests and procedures, drugs, dosages, and length of study, as well as the outcomes that will be measured. Each person participating in the study must agree to the rules set out by the protocol.
Why are clinical trials done?
Many clinical trials are done to see if a new drug or device is safe and effective for people to use. Clinical trials are also done for other reasons. Some compare existing treatments to determine which is better. The current, approved treatments are called the "standard treatments." Sometimes clinical trials are used to study different ways to use the standard treatments so they will be more effective, easier to use, and/or decrease side effects. Sometimes, studies are done to learn how to best use the treatment in a different population, such as children, in whom the treatment was not previously tested.
For most trials, researchers, doctors, and other health professionals administer the clinical trials according to strict rules set by the Food and Drug Administration (FDA). FDA sets the rules to make sure that people who agree to be in studies are treated as safely as possible.
Where can people find out about clinical trials?
People can find information about clinical trials now being conducted by searching www.clinicaltrials.gov. ClinicalTrials.gov is an interactive online database, managed by the National Library of Medicine. It provides information about both federally and privately supported clinical research in human volunteers. ClinicalTrials.gov is updated regularly and offers information on each trial's purpose, who is eligible to participate, locations, and phone numbers to call for more information.
Since ClinicalTrials.gov is only available online, individuals without Internet access can use the database at the public library or other publicly available internet portal.
Clinical trials can be sponsored by an organization such as a pharmaceutical company, a federal agency - for example, the National Institutes of Health or Veterans Administration -or an individual, such as a physician or health care provider. The sponsor determines the location(s) of the trials which are usually conducted at universities, medical centers, clinics, doctor's offices, and/or at hospitals, federally- and industry-funded research sites.
What is informed consent?
Informed consent is the process of learning the key facts about a clinical trial before deciding whether or not to participate. It is also a continuing process throughout the study to provide information for participants. To help someone decide whether or not to participate, the doctors and nurses involved in the trial explain the details of the study. If the participant's native language is not English, translation assistance can be provided. 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.
Clinical trials are conducted in phases. The trials at each phase have a different purpose and help scientists answer different questions:
In Phase I trials, researchers test an experimental drug or treatment in a small group of people (20-80) for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
In Phase II trials, the experimental study drug or treatment is given to a larger group of people (100-300) to see if it is effective and to further evaluate its safety.
In Phase III trials, the experimental study drug or treatment is given to large groups of people (1,000-3,000) to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the experimental drug or treatment to be used safely.
In Phase IV trials, post-marketing studies delineate additional information including the drug's risks, benefits, and optimal use.
Clinical trials test potential treatments in human volunteers to see whether they should be approved for wider use in the general population. A treatment could be a drug, medical device, or biologic, such as a vaccine, blood product, or gene therapy.
Potential treatments are studied in laboratory animals first to determine potential toxicity before they can be tried in people. Treatments having acceptable safety profiles and showing the most promise may then be considered for use in clinical trials.
It is not known whether a potential new medical treatment offers benefit to patients until clinical research on that treatment is complete. Clinical trials are an integral part of new product discovery and development, and are generally required by the Food and Drug Administration (FDA) before a new product can be brought to the market.
How Are People Protected?
FDA has authority over clinical trials for drug, biologic, and medical device products regulated by the agency. This authority includes studies that are funded by the U.S. Department of Health and Human Services (with joint oversight by FDA and the Office for Human Research Protections), as well as studies that are solely funded by industry or by private parties.
Clinical trial procedures are reviewed by institutional review boards (IRBs). These boards are composed of at least five members that include scientists, doctors, and lay people. They review and approve clinical trials taking place within their jurisdiction before the trials can begin.
The purpose of an IRB review is to ensure that appropriate steps are taken to protect the rights and welfare of participants as subjects of research. If the risks to participants are found to be too great, the IRB will not approve the research, or it will specify changes that must be made before the research can be done.
As part of their review, IRBs consider participant inclusion and exclusion requirements to be sure that appropriate people have been identified as eligible for the trial. They often look at how and where recruitment for clinical trials will occur.
IRBs review the adequacy of the informed consent document to ensure that it includes all the elements required by law, and that it is at an appropriate reading level and understandable to study participants.
To help protect the rights and welfare of volunteers and verify the quality and integrity of data submitted for review, FDA performs inspections of clinical trial study sites and anyone involved in the research.
Many groups play important roles in looking out for the safety of research subjects. These groups include FDA, other government agencies, and institutional review boards. There is also monitoring of studies by industry or private sponsors, as well as oversight and reporting by investigators and their staff.
What Are the Risks?
Clinical trials should be carefully designed to answer certain research questions. A trial plan called a protocol maps out what study procedures will be done, by whom, and why. Products are often tested to see how they compare to standard treatments or to no treatment.
FDA often provides extensive technical input to researchers conducting clinical trials, which may help them design better trials that can characterize effects of a new product more efficiently, while reducing risks to those participating in the trials.
The clinical trial team includes doctors and nurses, as well as other health care professionals. This team checks the health of the potential participant at the beginning of the trial and assesses whether that person is eligible to participate. Those found to be eligible--and who agree to participate--are given specific instructions, and then monitored and carefully assessed during the trial.
Some treatments being studied can have unpleasant, or even serious, side effects. Often these are temporary and end when the treatment is stopped. Others, however, can be permanent. Some side effects appear during treatment, and others may not show up until after the study is over.
The risks may vary depending on the treatment being studied and the health of the people participating in the trial. All known risks must be fully explained by the researchers before the trial begins. If new risk information becomes available during the trial, participants must be informed.
FDA is committed to protecting the participants of clinical trials, as well as helping to ensure that reliable information is provided to those interested in participating. Although efforts are made to minimize risks to clinical trial participants, some risk may be unavoidable because of the uncertainty inherent in clinical research involving new medical products. It's important, therefore, that people make their decision to participate in a clinical trial only after they have a full understanding of the entire process and the risks that may be involved.
Please note even more information on clinical trials can be accessed by visiting our links page.
The information above is provided by the U.S. Department of Health and Human Services (HHS), U.S. National Library of Medicine, National Institutes of Health, Food and Drug Administration (FDA), and can be accessed at: