Clinical trials (also known as clinical investigation or medical research) are an important part of the process in which new drugs, treatment plans, or other such interventions are tested and validated under very strict medical supervision. Clinical trials are generally of two basic types: investigational trials and observational studies.
The purpose of an investigationaltrial is to evaluate whether some new drug or procedure is effective in preventing or treating a disease. As an example, suppose drug A shows promise as an effective treatment for high blood pressure but a diet rich in vitamin Z has also demonstrated the same effect. An investigational clinical trial could be conducted to evaluate which of the two is the better treatment choice.
On the other hand, an observationalstudy (sometimes called an epidemiologic study) is designed to gather information about a large group of people as they go about their daily lives. The major difference between investigational and observational studies is that an investigational study will introduce some type of treatment or intervention while an observational study will generally avoid such changes in order to study the long term health trends of a selected group. An example of an observational study is the famous Framingham Study which has been underway for over 50 years and has yielded much valuable information about heart disease.
Since investigational clinical trials are usually of greater interest to the public at large, we will devote the remainder of this article to understanding some of the terms that will be encountered when discussing this type of research.
Any investigational study will begin by defining both the inclusion and exclusion criteria of the study. These criteria will determine who will be eligible to participate (inclusion) in the study and who will not be eligible (exclusion). By way of example, suppose that a drug company wants to evaluate the effectiveness of a new treatment for lung cancer but does not wish to deprive anyone of a treatment (such as surgery, chemotherapy, or radiation) that has been shown to be effective in the past. The inclusion criteria might include patients that have not benefited from other forms of treatment, whose cancer has spread to other organs, and are not expected to survive beyond a few months. Obviously, anyone not meeting these criteria will be excluded from the study.
Once a patient has met the requirements for inclusion in the clinical study the process cannot proceed until an informed consent has been obtained. Informed consent can be defined as furnishing each potential participant in the study with all the relevant information (such as potential complications, possible benefits, side effects from the investigational drug, and the probability of unforeseen complications) necessary for the potential study participant to make a decision as to whether or not to begin participation in the study. Only after these steps have been resolved will the participant enter (be enrolled in) the study.
Once the participant has entered the study he or she will be closely monitored for any unforeseen complications as well as those that can be reasonably expected to occur and were included in the informed consent process. It is important to remember that the participant always has the option to leave the study at any time. All investigational studies will also include an exit point (the point at which the investigational treatment has been completed and all the anticipated data has been obtained).
This article is intended to be a very basic introduction to the subject of clinical trials. It is not to be viewed as either endorsing clinical trials in general or suggesting that the reader participate in such studies. Always seek the advice of your health care provider or some other qualified professional that is familiar with your medical history.
For More Information
Clinical Trials.Gov: (US) This web site was created by both the National Institutes of Health and the National Library of Medicine and contains a more detailed discussion of clinical trials. It is easy to use, understand, and has numerous links to other related web sites.
CenterWatch.com: (US) This site is maintained by a privately-funded media company that publishes professional materials related to health care and clinical trials (this site is devoted to cardiovascular conditions but you can follow the links provided to other conditions).
The National Cancer Institute at the National Institutes of Health: (US) This site is devoted to the latest information on the prevention, diagnosis, and treatment of cancer. It contains a major database concerning both ongoing and proposed clinical trials at different locations across the
Cancer Backup: () This is the most comprehensive clinical trials information source for those residing in the
NCIC CTG (National Cancer Institute of Canada Cancer Treatment Group): (CA) Cancer treatment clinical trials underway in .
The University of Sydney Clinical Trials Centre: (AU) The Australian equivalent of the above links. Contains information on many clinical trials involving diseases other than cancer.