What is a clinical trial?
A clinical trial (also called clinical research) is a research study in human volunteers to answer specific health questions using a pre-defined protocol (i.e., study plan). Carefully conducted clinical trials are the safest ways to find treatments that work in people and ways to improve health. Interventional trials are those in which participants are assigned by the researcher to a particular experimental treatment or other intervention. Observational trials are those in which individuals are observed and their outcomes are measured by the researchers.
Are there criteria for who can join a clinical trial?
All clinical trials have requirements about who can participate in the study. These requirements are called eligibility criteria and they are based on such factors as age, type of disease, medical history and current medical condition. Some research studies seek volunteers with specific illnesses or conditions to be studied, while other trials need healthy volunteers.
What is a "healthy volunteer?"
A person with no known significant health problems who participates in research is known as a "healthy volunteer." Research procedures on these volunteers are typically limited to determining a safe dosing range and identifying potential side effects from the drug, not to provide any potential medical benefit to the volunteer.
What is a protocol?
All clinical trials must be conducted according to strict scientific and ethical principles. Every clinical trial must have a protocol or study plan that describes what will be done in the study, how it will be conducted, and why each part of the study is necessary - including details such as the criteria for patient participation, the schedule of tests, procedures, medications, the length of the study and potential risks to the patient.
What are the phases of a clinical trial?
Clinical trials are conducted in a series of steps, called phases - each phase is designed to answer a separate research question.
Phase I: Researchers test a new drug or treatment in a small group of people for the first time to evaluate its safety, determine a safe dosage range, and identify side effects
Phase II: The drug or treatment is given to a larger group of people to see if it is effective and to further evaluate its safety
Phase III: The drug or treatment is given to large groups of people to see if it is effective, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely
Phase IV: Studies are done after the drug or treatment has been marketed to gather information on the drug's risks, benefits, and optimal use
What is a placebo?
Placebos are inactive pills, liquids, or powders that have no treatment value. They are made to look like the real drug being tested in the clinical trial. Placebos allow the investigators to learn whether the drug being tested works better or no better than ordinary treatment. In many studies, there are successive time periods, with either the placebo or the investigational drug being investigated. In order not to introduce bias, the patient, and sometimes the staff, are not told when or what the changes are. If a placebo is part of a study and there is a chance you will receive it, you will always be informed in the consent form given to you before you agree to take part in the study. When you read the consent form, be sure that you understand what research approach is being used in the study you are entering.
What is the placebo effect?
Medical research must take into consideration the placebo effect - the real or apparent improvement in a patient's condition due to wishful thinking by the investigator or the patient. Researchers use three methods to eliminate such a bias from clinical trials. These methods have helped discredit some previously accepted treatments, as well as validate some new ones. These methods are the following: randomization, single-blind or double-blind studies, and the use of a placebo.
What is randomization?
Randomization is when two or more alternative treatments in the study are selected by chance, not by choice. The treatment chosen is given with the highest level of professional care and expertise, and the results of each treatment are compared. Analyses are done at intervals during a trial, which may last years. As soon as one treatment is found to be definitely superior, the trial is stopped. In this way, the fewest number of patients receive the less beneficial treatment.
What are single-blind and double-blind studies?
In single- or double-blind studies, the participants don't know whether they are being given investigational drug, placebo or an approved drug, and they can describe what happens to them without bias. Blinded studies are designed to prevent anyone (doctors, nurses, or patients) from influencing the results. This allows scientifically accurate conclusions to be drawn. In single-blind ("single-masked") studies, only the patient is not told what is being given. In a double-blind study, usually only the pharmacist knows; the doctors, nurses, patients, and other health care staff are not informed. If medically necessary, however, it is always possible to find out what the patient is taking.
What protections are there for participating in a clinical trial?
The ethical and legal codes that govern medical practice also apply to clinical trials. In addition, most clinical research is federally regulated with built in safeguards to protect the participants. The trial follows a carefully controlled protocol, a study plan which details what researchers will do in the study. In addition, every clinical trial in the US must be approved and monitored by an Institutional Review Board (IRB) to make sure the risks are as low as possible and do not outweigh any potential benefits.
An IRB is a committee of physicians, statisticians, patient advocates, and other members of the community that reviews the protocol, or study plan, to ensure that the study is ethical and that participants are not likely to be harmed.
An IRB can stop a study if it appears to be causing unexpected harm to participants, or if there is evidence that the risks outweigh the benefits. An IRB can also stop a study if there is clear evidence that the new treatment is effective, to make it more widely available.
What is informed consent?
Informed consent is the process of learning the important 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.
Your participation in any clinical trial is voluntary. Before you volunteer to participate, you will receive an informed consent document that explains the details of the study, including the potential risks and benefits, as well as your rights and responsibilities.
A member of the research team will discuss the study with you and answer your questions so you can make an informed decision about whether or not to participate. In addition, you have the right to ask questions throughout the course of the study and may withdraw consent (stop) at any time.
Since the decision to volunteer for a clinical trial is a personal one, you should decide in close consultation of your health care provider, family members, and friends.
Who can participate in a clinical trial?
All clinical trials have requirements about who can participate in a study. Requirements are based on such factors as age, type of disease, medical history, and current medical condition. Some research studies seek volunteers with illnesses or conditions to be studied, while other trials need healthy volunteers.
Factors that allow you to participate in a study are called "inclusion criteria." Factors that keep you from participating are called "exclusion criteria." The criteria are not used to reject people for any personal reason, but rather are used to identify appropriate participants and keep them safe. The criteria also help researchers ensure they will be able to answer the questions they plan to study.
Who sponsors clinical trials and where do they take place?
Clinical trials are sponsored by government agencies, private organizations, and individual researchers who are seeking ways to improve the health of people living with chronic and life-threatening illnesses. Sponsors include:
government agencies such as the National Institutes of Health (NIH), the Department of Defense (DOD), and the Department of Veteran's Affairs (VA)
pharmaceutical, biotechnology, and medical devices companies
health care institutions such as academic medical centers and health maintenance organizations (HMOs)
Clinical trials are conducted in a variety of locations, including hospitals, universities, doctors' offices, or community health clinics.
What are the benefits and risks of participating in a clinical trial?
There are both benefits and risks associated with clinical trials. By participating in a clinical trial, you may benefit by:
gaining access to new treatments that are not yet available to the public
obtaining expert medical care at a leading health care facility
playing an active role in your own health care
helping others by contributing to medical research
Clinical trials may also have risks:
there may be unpleasant, serious, or even life-threatening side effects from treatment
treatment may not be effective for some individuals
the study may require a lot of time for traveling to the study site, receiving treatments, or hospital stays
health insurance may not cover all the study costs
Can I leave a clinical trial after it has begun?
Yes, because your participation in a clinical trial is always voluntary you may leave it at any time - either before the study starts or at any time during the study or the follow-up period.
How can I find the results of a clinical trial?
If the results of a clinical trial are published, you may find them at:
Trial results may not be available even after a clinical trial ends
Sometimes, trials end before completion and researchers never publish the results