What is a clinical trial?
Although there are many definitions of clinical trials, they are generally considered to be biomedical or health-related research studies in human beings that follow a pre-defined protocol. ClinicalTrials.gov includes both interventional and observational types of studies. Interventional studies are those in which the research subjects are assigned by the investigator to a treatment or other intervention, and their outcomes are measured. Observational studies are those in which individuals are observed and their outcomes are measured by the investigators.
Why participate in a clinical trial?
Participants in clinical trials can play a more active role in their own health care, gain access to new research treatments before they are widely available, and help others by contributing to medical research.
Where do the ideas for trials come from?
Ideas for clinical trials usually come from researchers. After researchers test new therapies or procedures in the laboratory and in animal studies, the experimental treatments with the most promising laboratory results are moved into clinical trials. During a trial, more and more information is gained about an experimental treatment, its risks and how well it may or may not work.
Who sponsors clinical trials?
Clinical 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 such as the National Institutes of Health (NIH), the Department of Defense (DOD), and the Department of Veteran's Affairs (VA). Trials can take place in a variety of locations, such as hospitals, universities, doctors' offices, or community clinics.
What is a protocol?
A protocol is a study plan on which all clinical trials are based. The plan is carefully designed to safeguard the health of the participants as well as answer specific research questions. A protocol describes what types of people may participate in the trial; the schedule of tests, procedures, medications, and dosages; and the length of the study. While in a clinical trial, participants following a protocol are seen regularly by the research staff to monitor their health and to determine the safety and effectiveness of their treatment.
What is a placebo?
A placebo is an inactive pill, liquid, or powder that has no treatment value. In clinical trials, experimental treatments are often compared with placebos to assess the experimental treatment's effectiveness. In some studies, the participants in the control group will receive a placebo instead of an active drug or experimental treatment.
What is a control or control group?
A control is the standard by which experimental observations are evaluated. In many clinical trials, one group of patients will be given an experimental drug or treatment, while the control group is given either a standard treatment for the illness or a placebo.
What are the different types of clinical trials?
Treatment trials test experimental treatments, new combinations of drugs, or new approaches to surgery or radiation therapy.
Prevention trials look for better ways to prevent disease in people who have never had the disease or to prevent a disease from returning. These approaches may include medicines, vitamins, vaccines, minerals, or lifestyle changes. Diagnostic trials are conducted to find better tests or procedures for diagnosing a particular disease or condition. Screening trials test the best way to detect certain diseases or health conditions. Quality of Life trials (or Supportive Care trials) explore ways to improve comfort and the quality of life for individuals with a chronic illness.
For cancer treatments in particular, there are different types of trials:
Therapeutic trials make up the majority of cancer clinical trials. They offer new treatments to those who have advanced diseases such as late-stage cancer.
Adjuvant trials use additional treatments to increase the effectiveness of the primary therapy, such as those testing hormones to prevent the recurrence of breast cancer.
Prevention trials test agents that may help reduce the likelihood of developing diseases for those at high risk.
Translational trials examine a patient’s genes to determine what genetic makeup responds best to particular treatments.
Observational trials address health issues in large groups of people in natural settings.
What are the phases of clinical trials?
Clinical trials are divided into a series of four steps, or phases. The phase at which time certain patients become involved in a trial depends upon the stage of their disease, prior treatment, and the specific eligibility criteria of the trial. Each phase has a different purpose and helps scientists answer different questions.
- A Phase I trial is a new treatment that has not been tested, and researchers are looking for the best way to administer the treatment, determine how much can be given safely, and identify side effects. Phase I trials are usually offered only to a small group of approximately 20 to 80 patients with advanced disease who would not be helped by other known treatments.
- A Phase II trial takes the treatment one step further, assessing the activity of a particular therapy in a disease, often building upon leads from the Phase I trial. While patients are generally required to be previously untreated, participation in a Phase II trial doesn't usually preclude the patient from getting the standard treatment after they have received the investigational agent or study drug/therapy. Typically, the experimental study drug or treatment is given to a larger group during this phase (approximately 100-300 patients).
- If a treatment has shown activity against a particular disease, it is granted the status of a Phase III trial, where it is either added to existing treatment or compared to the standard treatment. Phase III trials typically involve larger groups of patients (approximately 1,000 to 3,000 patients) in order to confirm the treatment's effectiveness and monitor side effects.
- Phase IV trials refine the treatment to become part of standard care. This phase typically takes place after a drug or treatment has been marketed to further evaluate its effect on different populations of patients and examine long-term use.
Source: http://www.clinicaltrials.gov/
Used with permission of the National Library of Medicine
|