Bookmarks Share Print

Clinical trial frequently asked questions (FAQs)

  1. What are clinical studies?

    Clinical studies, also known as clinical trials, are research studies involving people who volunteer to participate. These studies play a key role in developing potential new drugs, vaccines, and medical devices.

  2. Why should I participate?

    The health of millions of people has been improved because of advances in medical care, supported by the willingness of thousands of individual patients like you to take part in clinical research trials. The role of volunteers in clinical research is critical in helping us answer questions and build the scientific basis that will improve the health of future generations.

  3. What is a "healthy volunteer"?

    A healthy volunteer is someone with no known or no significant health problems who participates in a clinical trial. Healthy volunteers are needed to participate in early phase studies to understand how a potential medicine works in the body. In addition, healthy volunteers are sometimes needed to help us define the limits of "normal” and act as a “comparison” group to patients with the disease being studied.

  4. What are Phase I, Phase II and Phase III studies?

    The Phase I trial, often conducted in healthy volunteers, is designed to evaluate safety and possible side effects and to determine appropriate dosages.

    The Phase II trial involves a drug whose dose and side effects are better known. Many more patient volunteers are tested (usually 100 to 250), to define side effects, and learn how the potential medicine is used in the body and how it might help the condition being studied.

    The Phase III trial compares the new potential drug against a commonly used drug or against a placebo. Some patient volunteers will be given the new potential drug and some the commonly used drug or a placebo. The trial is designed to figure out where the new potential drug might fit in the management of a particular condition.

  5. What is the placebo effect?

    The placebo effect is the real, or apparent, improvement in a patient's condition that results from the wishful thinking of either the investigator, the patient or both. Medical techniques use three methods to eliminate this problem from clinical trials: randomization, single-blind or double-blind studies, and the use of a placebo.

  6. What is the difference between single-blind and double-blind studies?

    In single- or double-blind studies, the participants don't know which medicine they are taking, so that measurements can be taken without bias. Blinded studies are designed to prevent people from influencing the results and to allow for the most scientifically accurate conclusions. In single-blind studies, only the patient is not told what medication they are receiving. In a double-blind trial, only the pharmacist knows what study medication a patient is receiving; the doctors, nurses, patients, and other clinical trial staff are not informed. If medically necessary, however, it is always possible to find out which medication the patient in the clinical trial is taking.

  7. Are there risks involved in participating in a clinical trial?

    There are risks involved in volunteering for a clinical trial. As you evaluate the risks of research, you should consider both the “type of harm” that might result from being a clinical trial volunteer and the “likelihood” of harm happening. Most clinical studies pose risks of minor discomfort, lasting only a short time, although some volunteers do experience complications that require medical attention. The specific risks associated with any clinical trial are described in detail in the informed consent form, which you are asked to sign before you agree to take part in any clinical trial. The major risks will be explained to you before you agree to participate, by a member of the research team who will answer your questions about the trial. Before you make a decision about whether you want to volunteer, you should carefully evaluate these risks.

  8. What safeguards are there to protect participants in clinical research?

    The following section describes safeguards that protect the safety and rights of volunteer subjects. These safeguards include:

    • The protocol review process
    • Informed consent procedures

    Protocol review. In almost every country, all new clinical trials will need to be reviewed by an institutional review board (IRB). The IRB, which consists of medical specialists, statisticians, nurses, social workers, and medical ethicists, is the advocate of the trial volunteer.

    Informed consent. Your participation in any clinical research trial is voluntary. For every trial in which you intend to participate, you will receive a document called "Information and Consent Form" that explains the trial in straightforward language. A member of the research team will discuss the protocol (a written description of the clinical trial) with you, explain its details, and answer your questions. You may discuss the Information and Consent Form with family and friends. You will not be hurried into making a decision, and you will be asked to sign the document only after you have been explained the nature of the protocol and have decided to agree to participate. At any time after signing the Information and Consent Form, you are free to change your mind and not participate further in the clinical study. This means that you are free to withdraw from the trial completely, or to refuse particular treatments or tests. Sometimes, however, refusing some treatment or tests will make you ineligible to continue the trial. If you wish to end your participation in the trial, or are no longer eligible, you will be referred back to your doctor.