FAQs about clinical studies

Clinical studies are research studies in which real people participate as volunteers. Clinical research studies (sometimes also called clinical trials) are a way of testing and developing new treatments and drugs for diseases and conditions. Clinical studies in the U.S. have to follow strict rules set by the National Institutes of Health and the U.S. Food and Drug Administration to ensure the safety of participants.

The phase 1 study is used to learn the "maximum tolerated dose" of a drug that does not produce unacceptable side effects. Patient volunteers are followed primarily for side effects, and not for how the drug affects their disease. Phase 1 studies typically offer little or no benefit to the volunteer subjects and usually involve a small group of patients.

The phase 2 study involves a drug whose dose and side effects are well known. The purpose is to further define side effects of the drug, learn how it is used in the body, and learn how it helps the condition under study. Some volunteer subjects may directly benefit from a phase 2 study. Phase 2 studies usually focus on a particular condition, and include fewer than 100 patients.

The phase 3 study compares a new drug against a commonly used drug or treatment. Some volunteer subjects will be given the new drug or treatment and some the commonly used drug or treatment. The study is designed to find out whether the new drug or treatment is better at managing the condition than the standard treatment or no treatment. Phase 3 trials often include large numbers of people across the country.

The phase 4 study is conducted to further evaluate the long-term safety and effectiveness of a drug or treatment. Phase 4 studies take place after the drug or treatment have been approved for standard use. Several hundred to several thousand people may take part in a phase 4 study.

Often studies are done to see whether a new drug or device is safe and effective for people to use. Sometimes studies are done to find different ways to use already approved medications or treatments.

The health of millions has been improved because of advances in science and technology, and the willingness of thousands of individuals to take part in clinical research. The role of volunteers as partners in clinical research is crucial to improve the health of future generations. Although there is no guarantee that the study treatment or drug will produce good results, if it is effective, study participants may be among the first to benefit. Study participants are also treated by experts in the field and many studies offer compensation to participants.

This is a person with no known significant health problems who participates in a research study to test a new drug, device, or treatment. Studies with these volunteers are designed to develop new knowledge, not to provide direct benefit to study participants. Healthy volunteers are needed for several reasons: When developing a new drug or treatment, healthy volunteers help define the limits of "normal." These volunteers serve as controls or comparisons for patient groups with certain medical conditions. Doctors and researchers learn about the drug or condition by comparing the patient group to the healthy volunteers. Often there is compensation available for healthy volunteers participating in research studies.

In single- or double-blind studies, the participants don't know which drug or treatment is being used. Blind studies are designed to prevent anyone (doctors, nurses, or patients) from influencing the results. This allows scientifically accurate conclusions. In single-blind studies, only the patient is not told what is being given. In a double-blind study, the doctors, nurses, patients, and other health care staff are not informed which drug or treatment is being used. If medically necessary, however, it is always possible to find out what the patient is taking.

In a randomized study participants will usually be evenly placed in different study groups. Participants do not know to which group they have been assigned. One group receives the study drug or treatment; the other receives the placebo or standard treatment. This process allows researchers to compare results between the two groups. It is important to note that many studies not require randomization. Study participants will always be informed about the type of study they are entering.

Placebos are harmless, inactive substances made to look like the real drug used in the clinical study. Placebos allow the researchers to learn whether the drug or treatment being given works better or no better than ordinary treatment or not treatment at all. In order not to introduce bias, the patient,and sometimes the staff, are not told which patients receive the placebo and which ones receive the drug. If a placebo is part of a study, you will always be informed in the consent form given to you before you agree to take part in the study. When you read the consent form, be sure that you understand what research approach is being used in the study you are entering.

Risks are involved in clinical research, as in routine medical care and activities of daily living. In thinking about the risks of research, it is helpful to focus on two things: the degree of harm that could result from taking part in the study, and the chance of any harm occurring. Most clinical studies pose risks of minor discomfort, lasting only a short time. Some volunteer subjects, however, experience complications that require medical attention. The specific risks associated with any research protocol are described in detail in the consent document, which you are asked to sign before taking part in research. In addition, the major risks of participating in a study will be explained to you by a member of the research team, who will answer your questions about the study. Before deciding to participate, you should carefully weigh these risks.

Your participation in any clinical studies is always voluntary. For every study in which you intend to participate, you will receive a document which explains the study in straightforward language. A member of the research team will discuss the study with you, explain its details, and answer your questions. You will not be hurried into making a decision, and you will be asked to sign the document only after you understand the nature of the study and agree to the commitment. At any time after signing up for the study, you are free to change your mind and decide not to participate further.

Source: Adapted from NIH Clinical Center, FAQs about Clinical Studies, 2011