Clinical Trials Overview

What are clinical trials?

Clinical trials are studies, managed by government agencies, educational institutions, private not-for-profit organizations, or commercial businesses, to develop, produce, and evaluate the effectiveness of new treatments for diseases.

What are some types of clinical trials?

According to the National Cancer Institute, there are different types of cancer clinical trials, including:

  • Prevention trials designed to keep cancer from developing in people who have not previously had cancer.

  • Prevention trials designed to prevent a new type of cancer from developing or keep cancer from coming back in people who have already had cancer.

  • Early detection or screening trials to find cancer, especially in its early stages.

  • Treatment trials to test new therapies in people who have cancer.

  • Quality of life studies to improve comfort and quality of life for people who have cancer.

  • Behavioral studies to evaluate ways of modifying cancer-causing behaviors, such as tobacco use.

  • Genetic studies address how genetic makeup affects detection, diagnosis, and treatment of cancer.

What are the phases of a clinical trial?

Most clinical research progresses in an orderly series of steps or phases.

  • Phase 0 trials are the earliest steps in testing new treatments in humans. A small number of people are studied and the focus is on learning how the agent is processed by the body and how the agent affects the body. No information is gathered on safety or effectiveness in treating cancer.

  • Phase I trials are the first studies to evaluate how a new therapy should be administered - how it should be given, how often, and in what dosage. The focus is to determine safety (drug dose, device safety, or other therapy's safety) for the next phase of testing.

  • Phase II trials provide preliminary information about how well the new therapy works, and generates more information about its safety and benefits. A Phase II study usually focuses on a particular type of cancer.

  • Phase III trials compare a promising new therapy, combination of treatments, or procedure with a current standard of treatment. These trials often enroll large numbers of people and may be done at may doctors' offices, clinics, and cancer centers nationwide, or even worldwide.

  • Phase IV trials include the continuing evaluation that takes place after FDA (Food and Drug Administration) approval, when the therapy is already available for general use.

What is a clinical trial protocol?

Clinical trial protocols are the action plans or guidelines that must be followed during the course of any study. Guidelines may cover:

  • The design of the study - what will be studied and how

  • Who may participate - criteria for patients who enter the study

  • What treatments and medical tests will be used to follow the participants

  • Specific research questions

  • What information will be collected

Several research centers may be involved in the study, and each uses the same protocols to ensure that information from all centers can be combined and compared.

Where are trials conducted?

Large cancer centers, university hospitals, local medical centers, or physician offices; all may be included in managing clinical trials. Informed consent is a process designed to protect potential participants through detailed description of important facts about a specific clinical trial. There may be only one or two locations involved in a particular study, or hundreds around the country, or even around the world.

Who can participate in a trial?

Each protocol in a trial defines specific characteristics, called eligibility criteria, that participants should have in order to participate in the study. Characteristics may include type of disease and its stage, as well as the participant's age and general health.

Eligibility criteria help assure that the study results answer the research question and identify who will benefit in the future from the approach being studied.

How are trial participants protected?

More Information on Cancer