Clinical Trials from A to Z

Clinical trials are a type of research study that uses human volunteers to see if certain medications or treatments are safe and effective. This type of research is an important tool researchers use to find ways to improve health and offer new treatment options for a wide variety of health conditions. While there are many ways in which clinical trial studies are designed, most are either interventional studies, in which a controlled environment is used to see if experimental treatments are safe and effective; or observational, in which natural settings are used to see how therapies or treatments affect large groups of people.

Most clinical trial studies are sponsored by pharmaceutical or biotechnology companies, medical institutions, and foundations. In some cases, a government agency such as the National Institutes of Health (NIH) provides funding for the trials. The United States Food and Drug Administration (FDA) oversees all clinical trial studies done in the U.S. It is responsible for determining if a clinical trial is needed, approves the scope and goals of the trial, helps select the researchers who will run the trial, review the results of the clinical trial, and determine if the new medication or device will be made available to the public.

Who can participate in a clinical trial?
In order for a clinical trial to produce reliable results, participants in the study must be carefully selected. All clinical trials have rules and guidelines about who can and cannot participate. These are called inclusion and exclusion criteria and involve such factors as age, gender, treatment history, stage of disease, and other medical conditions. Factors that allow a person to participate in a clinical trial are called the inclusion criteria and factors that do not allow a person to participate are called exclusion criteria. Some trials look for participants who are healthy and have no previous health conditions while other studies only want participants with certain illness to participate. Before a clinical trial can accept any participants, the sponsor of the study must clearly describe the inclusion and exclusion criteria.

What are the different types of clinical trials?
There are a variety of types of clinical trials including the following:

• Treatment trials - test new treatments.

• Prevention trials - look for new ways to keep people healthy or keep a disease from returning.

• Diagnostic trials - look for better ways to diagnose a disease.

• Screening trials - look for better ways to detect a disease.

• Quality of life trials - look for better ways to improve the quality of life of people with chronic illnesses.

Each clinical trial is conducted in four phases. The FDA must approve each phase before the study can continue.

Phase I:
In this phase, a new drug or treatment is tested on a small group of healthy people to determine safe dosage, study how the drug works in the body, and see if it has any side effects. The overall safety of the drug is not known during this phase.

Phase II:
The drug or treatment can now be tested on a larger group of people to see if it is effective and to further test its overall safety. Rating scales are developed and used to record data during this phase.

Phase III:
Now the drug or treatment is ready to be tested on even larger numbers of people. The study will look even more closely at the drug's effectiveness, if it has any side effects, overall safety, and how it can improve a person's quality of life. Most drugs that reach this phase are considered for FDA approval.

Phase IV:
Once given FDA approval, the trial can enter into the final phase, which involves monitoring the drug after it has been released to the public. In this phase, researchers look for additional information such as risks, benefits, and optimal or additional uses of the drug. In some cases this phase is used to test the drug on a sub-group of people (such as patients over a certain age).