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Definition of Clinical trials
Clinical trials: Trials to evaluate the effectiveness and safety of medications or medical devices by monitoring their effects on large groups of people.
Clinical research trials may be conducted by government health agencies such as NIH, researchers affiliated with a hospital or university medical program, independent researchers, or private industry.
Usually volunteers are recruited, although in some cases research patient may be paid. Patients are generally divided into two or more groups, including a control group that does not receive the experimental treatment, receives a placebo (inactive substance) instead, or receives a tried-and-true therapy for comparison purposes.
Typically, government agencies approve or disapprove new treatments based on clinical trial results. While important and highly effective in preventing obviously harmful treatments from coming to market, clinical research trials are not always perfect in discovering all side effects, particularly effects associated with long-term use and interactions between experimental drugs and other medications.
For some patients, clinical research trials represent an avenue for receiving promising new therapies that would not otherwise be available. Patients with difficult to treat or currently "incurable" diseases may want to pursue participation in clinical research trials if standard therapies are not effective. Clinical research trials are sometimes lifesaving.
There are four possible outcomes from a clinical trial:

  • Positive trial -- The clinical trial shows that the new treatment has a large beneficial effect and is superior to standard treatment.
  • Non-inferior trial -- The clinical trial shows that that the new treatment is equivalent to standard treatment. Also called a non-inferiority trial.
  • Inconclusive trial -- The clinical trial shows that the new treatment is neither clearly superior nor clearly inferior to standard treatment.
  • Negative trial -- The clinical trial shows that a new treatment is inferior to standard treatment.


Clinical research and clinical trials facts

  • Clinical trials are a form of clinical research that follows a defined protocol that has been carefully developed to evaluate a clinical question.
  • Clinical trials are in use to test therapies, treatments for different diseases, the safety and efficacy of new drugs, and a number of other conditions.
  • Clinical trials may investigate the effectiveness of new drug treatments, new combinations of drugs, surgical procedures, or behavioral and lifestyle modifications.
  • Clinical trials are broken down into phases, with each phase having a different purpose within the trial.
  • An Institutional Review Board (IRB) consisting of physicians, statisticians, researchers, patient advocates, and others must preapprove every clinical trial in the U.S and Canada. This ensures that the trial is ethical and protects patients' rights.
  • Every clinical trial follows a protocol that describes what types of people may participate in the trial; outlines the exact the schedule of tests, procedures, medications, and/or dosages involved in the trial; and specifies the length of the study.
  • Each trial has specific inclusion and exclusion criteria to determine the exact patient populations that may participate. Inclusion criteria may be based on age, gender, underlying disease, health history, or other factors.
  • Double-blinded trials offer the advantage of allowing the treating health-care team and the patient to make unbiased observations about patient progress and the effectiveness of the treatment being evaluated.
  • Clinical trials may be sponsored and funded by government agencies, institutions, hospitals, physicians, pharmaceutical or biotechnology companies, advocacy groups, or other organizations.


Why is clinical research important?                                                      
Clinical research is important in order to develop new therapies and diagnostic procedures as well as to understand how diseases develop. Observational studies may help identify risk factors for the development of a particular disease, such as the association between smoking and lung cancer. Outcomes-based research can help doctors identify the most effective therapies and treatments for a number of conditions. Another aspect of clinical research is the development of new technologies for use in health care, ranging from surgical tools and materials to hearing aids and artificial limbs.


What is informed consent?
Informed consent is giving your consent to participate in the clinical trial after having learned about the trial and having had the opportunity to ask questions. You should be fully aware of all the details, risks vs. benefits, and expectations of the trial before agreeing to participate. When you give informed consent, you sign a document that describes the rights of the participants as well as gives details of the study and names of the investigators who are conducting the study and contact information for these people.

Is patient privacy maintained in a clinical trial?
Clinical trials are required to maintain strict patient privacy. Your name will not be published anywhere that data about the trial are published or included in any publicly available information. Some clinical trials may require that you be seen and examined by a larger treatment team than would typical medical care.

Who can participate in a clinical trial?
Each trial has specific inclusion and exclusion criteria to determine the exact patient populations that may participate. Individuals who fit the predefined and preapproved inclusion criteria for a trial may participate if the trial is currently accepting participants. Inclusion criteria are based on factors such as patient age, gender, the type and stage of a disease, previous treatment history, and other medical conditions. Some clinical trials seek participants with illnesses or conditions to be studied in the clinical trial, while others need healthy participants.

Are people paid for participating in clinical trials?
Some clinical trials offer monetary compensation for participants. Other trials may offer their participants free health care that is related to the condition being studied, or screening examinations. There are no requirements for those who sponsor clinical trials to pay or otherwise compensate participants.

What are the pros and cons of participating in a clinical trial?
The benefits of clinical trials are many and range from taking an active role in the management of one's own health care, helping others by aiding the process of knowledge acquisition and development of enhanced treatments, being cared for by leading health-care teams in a given field, and in some cases, receiving access to new treatments before they are approved. However, there are also risks, including side effects of drugs and risks of any procedures that may be performed. In some cases, clinical-trial participation may require more frequent doctor visits or hospitalizations than standard care, and you may have to travel to a study site that is farther away than your local health-care practitioner's office.
Some questions you may want to ask before participating in a clinical trial include the following:

  • What is the purpose of the trial?
  • Is a new type of treatment being tested? How does this differ from the accepted or standard therapy for my condition?
  • Has the drug or treatment ever been tested before?
  • How will participation impact my daily life and schedule? Will it be necessary to be in the hospital?
  • What are the risks and possible side effects of the treatment?
  • Who will pay for the treatments? Will I receive reimbursement or any type of compensation for my time or expenses?
  • How long is the trial expected to last?
  • How will I receive results of the trial, and how will I know if the treatment is successful?


Can a person leave a clinical trial once it has started?
An informed consent document is not a legal contract that requires participation in a study for the length of a study. A participant is free to leave a clinical trial at any time.

What happens after a clinical trial is completed? Is there follow-up care?
The researchers in the trial will stay in contact with participants and inform them of the conclusions of the trial. In some cases, you may be asked to provide long-term follow-up in the form of patient surveys or periodic health examinations. Since most clinical trials provide short-term treatments related to a specific condition, they are not a substitute for primary health care. Your regular health-care provider should be aware of the trial and will work with the researchers during the trial. When the trial is over, you will continue to receive care through your primary provider and any other practitioners required for your condition.


United States. National Institute of Child Health & Human Development. "Clinical Research & Clinical Trials." <>.
United States. National Institutes of Health. <>.


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