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Frequently Asked Questions About Clinical Research

What is clinical research?

Clinical research is research conducted with human subjects, or material of human origin, in which the researcher directly interacts with human subjects. Clinical research helps doctors and researchers to find new and better ways to understand, detect, control, and treat illness. A clinical research study is a way to find answers to difficult scientific or health questions. For example, the study might explore the best ways to treat people with colon cancer. By studying cancer cells from patients, researchers may be able to determine the specific genetic mutations (changes in gene sequence) that caused the normal, healthy cells to become cancerous, and may help doctors decide on the best drugs to prescribe or surgeries to perform. Clinical research today may help other doctors in the future screen their healthy patients before they ever develop cancer.

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What is a protocol?

All clinical studies are based on a set of rules or directions called a protocol. A protocol describes what types of people are eligible to participate in the study; determines the schedule of tests, procedures, medications, and dosages; and sets the length of the study.

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What is a clinical trial?

A clinical trial is a research study in which one or more human subjects are prospectively assigned to one or more interventions (which may include placebo or other control) to evaluate the effects of those interventions on health-related biomedical or behavioral outcomes.

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What are clinical trial "phases?"

Clinical trials of experimental drugs proceed through four phases:

In Phase I clinical trials, researchers test a new drug or treatment for the first time in a small group of normal, healthy volunteers (about 20 to 80) to evaluate its safety, determine a safe dosage range, and identify side effects.

In Phase II clinical trials, the study drug or treatment is given to a larger group of people (about 100 to 300), including patients with the particular disease, to see if the drug or treatment is effective, and to further evaluate its safety.

In Phase III clinical trials, the study drug or treatment is given to large groups of people (from 1,000 to 3,000), including patients, to confirm its effectiveness, monitor side effects, compare it to other commonly used treatments, and collect information that will allow the drug or treatment to be used safely.

Phase IV clinical trials are done after the drug or treatment has been approved by the FDA and marketed for public use. These studies continue testing the drug or treatment to collect information about its effect in various populations and gather data on any side effects associated with long-term use.

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What are "blind" or "masked" studies?

In many clinical trials, one group of patients will be given an experimental drug or treatment, while a control group is given either a standard treatment for the illness, or a placebo (a harmless "fake" drug), or no treatment at all.

In a "blinded" or "masked" study, participants do not know whether they are getting the drug being tested, or whether they are in the control group. The goal is to prevent the so-called "placebo effect" from influencing the results of the experiment. The placebo effect is the phenomenon of patients feeling better simply because they think they are receiving a helpful drug or treatment.

Sometimes, clinical trials are "double-blind" or "double-masked." That means that neither the participants, nor the study staff members, know who is receiving the experimental drug and who is in the control group. Studies are performed in this way so that neither the patients' nor the doctors' expectations about the experimental drug can influence the observations and results.

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Should I volunteer for clinical research?

Clinical research is a vital part of finding new treatments and cures for diseases. Carefully conducted clinical studies are the fastest way to find treatments that are safe and effective. By volunteering for a clinical study, you would be participating in research that may result in a new treatment for a deadly or debilitating disease.

Before you agree to participate in a study, you must be given complete information about the study, known as "informed consent." Informed consent involves two essential components: a document and a process. The informed consent document gives a summary of the research project (including the study's purpose, research procedures, potential benefits and risks, etc.) and explains the individual's rights as a research participant. This document is part of an informed consent process, which consists of conversations between the research team and the participant, and may include other supporting material such as study brochures. The informed consent process provides research participants with ongoing explanations that will help them make informed decisions about whether to begin or continue participating in the research project (See: Informed Consent for Genomics Research). The Food and Drug Administration (FDA) provides details about informed consent with the information page: Informed Consent for Clinical Trials [].

Because participating in a clinical study is an important decision, there are many questions that you should consider before agreeing to participate. The Centers for Disease Control and Prevention (CDC) have prepared a list of questions to help you get the information you need to make a decision about participating: Taking Part in Research Studies: What Questions Should You Ask? [].

Clinical Research at NHGRI

Clinical researchers at the National Human Genome Research Institute (NHGRI) are developing advanced methods for studying the fundamental mechanisms of inherited and acquired genetic disorders. Their goals include both discovering the molecular basis of human genetic diseases, and creating new technologies to accelerate further genetic research.

NHGRI investigators are working to uncover the genetic components of common disorders such as cancer, diabetes, and heart disease, as well as less common conditions such as Marfan syndrome (Learning About Marfan Syndrome) and neurofibromatosis (Learning About Neurofibromatosis).

To this end, NHGRI scientists often study families with a history of inherited diseases. This helps to unravel the complex roles that multiple genes and environmental factors play in disease. Such studies will enable the development of effective and reliable gene-based diagnostic tests, and can lay the foundation for genetic treatments.

Additional Information About Clinical Trials Background Information []
Comprehensive information about participating in clinical trials, including how they work, what patients should know, what are the benefits and risks, and how volunteers are protected. Hosted by the National Institutes of Health (NIH) and the National Library of Medicine (NLM).

Clinical Trials Fact Sheet []
Explanation of different types of clinical trials, including how participants are selected, how participants benefit from being part of a trial, some possible risks, and questions you may want to ask your health care provider before entering a trial.

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How do I find information about clinical trials for specific conditions?

Information about clinical trials for specific conditions can be obtained by consulting the following Web sites:

  • Current NHGRI Clinical Studies
    A listing of NHGRI investigators' clinical studies that are currently recruiting.
    A comprehensive database of about 5,700 current clinical studies sponsored by the federal government and the pharmaceutical industry. Search by disease, treatment, sponsor or keyword. Hosted by NIH and the NLM.
  • Search the Studies at NIH []
    Database of all clinical studies being conducted at the NIH Clinical Center, Bethesda, Md. Search by diagnosis, signs and symptoms, or key words or phrases.

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Last Updated: August 11, 2017

See Also:

Talking Glossary
of Genetic Terms

Definitions for genetic terms found on this page

Current NHGRI Clinical Studies

Clinical Research
Program Overview

On Other Sites:
Search for current clinical trials.