Learn more about clinical trials:

What Are Clinical Trials? What Are the Different Types of Clinical Trials? How Are Clinical Trials Funded? Who Participates in Clinical Trials? What Is Informed Consent? Who Can Participate in Clinical Trials? What Are the Benefits and Risks?

What Are Clinical Trials?

A clinical trial, also called clinical research, is a study on people (who have volunteered) to answer specific health question. For example, a clinical trial might determine whether a certain drug or treatment prevents a particular disease or condition.  Back to Top

What are the Different Types of Clinical Trials?

There are five different types of clinical trials. Each type focuses on a different aspect of medical treatment.

Treatment Trials:	Treatment trials test experimental drugs, procedures, and other treatment.
Prevention Trials:	Prevention clinical trials focus on disease prevention.
Diagnostic Trials:	Diagnostic clinical trials focus on finding better ways diagnose and evaluate a specific disease or condition.
Screening Trials:	Screening clinical trials focus on better identifying and detecting diseases and conditions.
Quality of Life Trials:	Quality of Life clinical trials focuses on ways to better quality of life for people with chronic diseases or conditions.

Clinical Trials are conducted in four phases. Each phase has a different purpose and answers different questions.

Phase 1:	In Phase I clinical trials, an experimental drug or treatment is tested on a small group, usually 20-80 people, to ascertain its safety, determine a safe dose, and identify any side effects.
Phase 2:	In Phase II clinical trials, researchers of the study further test the experimental drug or treatment in a larger group, usually 100-300 people, to evaluate its effectiveness and further ascertain its safety.
Phase 3:	In Phase III clinical trials, the experimental drug or treatment is tested on a much larger group, usually 1,000-3,000 people, to validate its effectiveness, examine side effects, further collect data to allow the experimental drug or treatment to be used safely, and compare it against current standard treatments. In comparing the experimental drug or treatment to current standard treatments, one part of the group will receive the experimental drug or treatment and the other part of the troup will receive a standard treatment or a placebo (a treatment that has no effect), in a randomized manner.
Phase 4:	After the drug or treatment is approved by the U.S. Food and Drug Administration (FDA), Phase IV clinical trials (also known as post-marketing studies) may be conducted to collect more information including the drug or treatment's risks, benefits, and the best method to use it.

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Who Participates in Clinical Trials? What Is Informed Consent? Participation in a clinical trial is voluntary. At any time, a participant can change her/his mind and withdraw from the clincial trial. Before a person can participate in a clinical trial, s/he must provide the researcher with consent and such consent must only by given once the person fully understands the clincial trial. Informed consent is the process by which a person learns key details about a clinical trial before s/he decides whether or not to participate. During this process, doctors and research coordinators (usually nurses) will describe the details of the clinical trial such as its purpose, duration, required procedures and visits, key personnel and contacts, as well as risks and benefits in the experimental drug or treatment. All of this information is contained in a document (commonly known as the informed consent form). Once this information is explained, the person will then decide whether or not to participate. If s/he decides to participate, then the document is signed to memorialize her/his informed consent. The informed consent form is not a contract. At any time, a participant can stop her/his participation and withdraw from the clinical trial.    Back to Top

Who Can Participate in Clinical Trials? Each clinical trial contains guidelines about who can and cannot participate. These guidelines are maintained to ensure the safety of participants of the clinical trial as well as potential participants. They are also used to ensure that the purpose of the study is effectively answered. These guidelines are never used to personally reject a person from the clinical trial. Each clinical trial will clearly state inclusion criteria and exclusion criteria. Inclusion criteria are a list of the factors that will permit someone to participate. Exclusion criteria are a list of the factors that will disallow a person to participate. Thus, in order to participate in a clinical trial, a person must have all the factors listed in the inclusion criteria and not have any of the factors in the exclusion criteria. Both sets of criteria may contain factors based on age, gender, ethnicity, disease or condition (or lack of), fertility, and other health factors.   Back to Top

What Are the Benefits and Risks? The benefits of a clinical trial that is well designed and conducted are: May gain access to new research treatment that may not be widely available May obtain expert medical care at leading medical centers Contributing to medical research and future medical treatments

The risks in participating in a clinical trial are: Unpleasant, serious, and even life-threatening side effects Treatment may not be effective Participation may require more time and attention than receiving standard care (e.g. travel to the research site, additional tests or treatments, hospital stays, complex dosage)

Because of the above factors, it is important that a person provide their informed consent to a researcher before her/his participation.

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