Clinical trials are research studies conducted with people who volunteer to take part testing how well new medical approaches work. Each study answers scientific questions and tries to find better ways to prevent, screen for, diagnose, or treat a disease.
top of pageClinical trials are sponsored or funded by a variety of organizations or individuals such as physicians, medical institutions, foundations, voluntary groups, and pharmaceutical companies, in addition to federal agencies. Trials can take place in a variety of locations, such as hospitals, universities, doctors' offices, or community clinics.
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Research with people is conducted according to strict scientific and ethical principles. Every clinical trial has a protocol which acts like a "recipe" for conducting the trial. The plan describes what will be done in the study, how it will be conducted, and why each part of the study is necessary. The same protocol is used by every doctor or research center taking part in the trial.
To ensure the safety of those in the study various approvals are required; these vary depending on the country but usually include a central review by a government department and also locally. The review ensures participants are treated humanely and ethically and whether the likely benefit of the treatment is worth its risk.
Each study's protocol has guidelines for who can or cannot participate in the study. These guidelines, called eligibility criteria, describe characteristics that must be shared by all participants. The criteria differ from study to study. They may include age, gender, medical history, and current health status.
Enrolling participants with similar characteristics ensures that the results will be due to what is under study and not other factors. In this way, eligibility criteria help researchers achieve accurate and meaningful results. These criteria also make certain that people who could be made worse by participating in the study are not exposed to the risk.
Informed consent is a process by which people learn the important facts about a clinical trial to help them decide whether to participate. This information includes details about what is involved, such as the purpose of the study, the tests and other procedures used in the study, and the possible risks and benefits. In addition to talking with the doctor or nurse, people receive a written consent form explaining the study. People who agree to take part in the study are asked to sign the informed consent form. However, signing the form does not mean people must stay in the study. People can leave the study at any time-either before the study starts or at any time during the study or the follow-up period. The informed consent process continues throughout the study. If new benefits, risks, or side effects are discovered during the study, the researchers must inform the participants. They may be asked to sign new consent forms if they want to stay in the study.
top of pageClinical trials take place in doctors' offices, medical centers, community hospitals and clinics. Clinical trials may include participants at one or two highly specialized centers, or they may involve hundreds of locations at the same time.
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Clinical trials are usually conducted in a series of steps, called phases.
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After a clinical trial is completed, the researchers look carefully at the data collected during the trial before making decisions about the meaning of the findings and further testing. After a phase I or II trial, the researchers decide whether to move on to the next phase, or stop testing the agent or intervention because it was not safe or effective. When a phase III trial is completed, the researchers look at the data and decide whether the results have medical importance.
The results of clinical trials are often published in peer-reviewed, scientific journals and at company or other public websites like ClinicalStudyResults.org on the internet. Peer review is a process by which experts review the report before it is published to make sure the analysis and conclusions are sound. If the results are particularly important, they may be featured by the media and discussed at scientific meetings and by patient advocacy groups before they are published. Once a new approach has been proven safe and effective in a clinical trial, it may become standard practice. (Standard practice is a currently accepted and widely used approach.)
The benefits of participating in a clinical trial include the following:
The possible risks of participating in a clinical trial include the following:
It is important for people to ask questions before deciding to enter a clinical trial. Some questions people might want to ask their doctor or nurse are below.
The Study
Possible Risks and Benefits
Participation and Care
Personal Issues
Cost Issues
Cost issues can depend on individual regulations in countries and health care insurance providers.
For further information please visit the glossary at the IFPMA clinical trials page, based on an NCI fact sheet, National Cancer Institute.
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