Clinical Studies Frequently Asked Questions

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Choosing to participate in a clinical study is an important personal decision. The following frequently asked questions provide detailed information about clinical studies. In addition, it is often helpful to talk to a physician, family members, or friends about deciding to join a study. After identifying some study options, the next step is to contact the study team and ask questions.


What is an investigational drug?

Investigational or experimental drugs are new drugs that have not yet been approved by the FDA (or local regulatory agency) or approved drugs that have not yet been approved for a new use, and are in the process of being tested for safety and effectiveness.

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Who can participate in a clinical study?

All clinical studies have guidelines about who can participate. Using inclusion/exclusion criteria is an important principle of medical research that helps to produce reliable results. The factors that allow someone to participate in a clinical study are called "inclusion criteria" and those that disallow someone from participating are called "exclusion criteria". These criteria are based on such factors as age, gender, the type and stage of a disease, previous treatment history, and other medical conditions. Before joining a clinical study, a participant must qualify for the study. Some research studies seek participants with illnesses or conditions to be studied in the clinical study, while others need healthy participants. It is important to note that inclusion and exclusion criteria are not used to reject people personally. Instead, the criteria are used to identify appropriate participants and keep them safe. The criteria help ensure that researchers will be able to answer the questions they plan to study.

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What happens during a clinical study?

The clinical study team includes doctors, nurses and other health care professionals. They check the health of the participant at the beginning of the study, give specific instructions for participating in the study, monitor the participant carefully during the study, and stay in touch after the study is completed.

Some clinical studies involve more tests and doctor visits than the participant would normally have for an illness or condition. For all types of studies, the participant works with a study team. Clinical study participation is most successful when the protocol is carefully followed and there is frequent contact with the study staff.

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What is informed consent?

Informed consent is the process of learning the key facts about a clinical study before deciding whether or not to participate. It is also a continuing process throughout the study to provide information for participants. To help someone decide whether or not to participate, the doctors and nurses involved in the study explain the details of the study. If the participant's native language is not English, translation assistance can be provided. Then the research team provides an informed consent document that includes details about the study, such as its purpose, duration, required procedures, and key contacts. Risks and potential benefits are explained in the informed consent document. The participant then decides whether or not to sign the document. Informed consent is not a contract, and the participant may withdraw from the study at any time.

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What are the benefits and risks of participating in a clinical study?
  • Play an active role in their own health care.
  • Gain access to new research treatments before they are widely available.
  • Obtain expert medical care at leading health care facilities during the study.
  • Help others by contributing to medical research.

There are risks to clinical studies.

  • There may be unpleasant, serious or even life-threatening side effects to experimental treatment.
  • The experimental treatment may not be effective for the participant.
  • The protocol may require more of their time and attention than would a non-protocol treatment, including trips to the study site, more treatments, hospital stays or complex dosage requirements.

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What are side effects and adverse reactions?

There are risks, discomforts, and inconveniences associated with any clinical study. You may have side effects from taking the investigational drug. Side effects are any undesired actions or effects of the investigational drug or treatment. Potential side effects will be discussed with you during the informed consent process; however, all of the risks associated with taking the investigational drug may not currently be known. Throughout the clinical study you will be checked by the study team for side effects and it is very important that you tell the study doctor or nurse of any side effects that you have. Investigational drugs must be evaluated for both immediate and long-term side effects.

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How is the safety of the participant protected?

Every clinical study must be approved and monitored by an Institutional Review Board (IRB) or Ethics Committee (EC) to make sure the risks are as low as possible and are worth any potential benefits. An IRB or EC is an independent committee of physicians, statisticians, community advocates, and others that ensures that a clinical trial is ethical and the rights of study participants are protected.

The ethical and legal codes that govern medical practice also apply to clinical trials. In addition, most clinical research is regulated by the government with built in safeguards to protect the participants. The trial follows a carefully controlled protocol, a study plan which details what researchers will do in the study. As a clinical trial progresses, researchers report the results of the study at scientific meetings, to medical journals, and to various government agencies. Individual participants' names will remain secret and will not be mentioned in these reports.

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What should people consider before participating in a study?

People should know as much as possible about the clinical study and feel comfortable asking the members of the health care team questions about it, the care expected while in a study, and the cost of the study. The following questions might be helpful for the participant to discuss with the health care team. Some of the answers to these questions are found in the informed consent document.

  • What is the purpose of the study?
  • Who is going to be in the study?
  • Why do researchers believe the experimental treatment being tested may be effective?
  • Has it been tested before?
  • What kinds of tests and experimental treatments are involved?
  • How do the possible risks, side effects, and benefits in the study compare with my current treatment?
  • How might this trial affect my daily life?
  • How long will the trial last?
  • Will hospitalization be required?
  • Who will pay for the experimental treatment?
  • Will I be reimbursed for other expenses?
  • What type of long-term follow up care is part of this study?
  • How will I know that the experimental treatment is working?
  • Will results of the studies be provided to me?
  • Who will be in charge of my care?

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What kind of preparation should a potential participant make for the meeting with the research coordinator or doctor?
  • Plan ahead and write down possible questions to ask.
  • Ask a friend or relative to come along for support and to hear the responses to the questions.
  • Bring a tape recorder to record the discussion to replay later.

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Can a participant leave a clinical study after it has begun?

Yes. A participant can leave a clinical study, at any time. When withdrawing from the study, the participant should let the research team know about it, and the reasons for leaving the study.

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What is a protocol?

A protocol is a study plan on which all clinical studies are based. The plan is carefully designed to safeguard the health of the participants as well as answer specific research questions. A protocol describes what types of people may participate in the study; the schedule of tests, procedures, medications, and dosages; and the length of the study. While in a clinical study, participants following a protocol are seen regularly by the research staff to monitor their health and to determine the safety and effectiveness of their treatment.

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What is a placebo?

A placebo is an inactive pill, liquid, or powder that has no treatment value. In clinical trials, experimental treatments are often compared with placebos to assess the experimental treatment's effectiveness. In some studies, the participants in the control group will receive a placebo instead of an active drug or experimental treatment.

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What is a control or control group?

A control is the standard by which experimental observations are evaluated. In many clinical trials, one group of patients will be given an experimental drug or treatment, while the control group is given either a standard treatment for the illness or a placebo.

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What are the phases of clinical trials?

Clinical trials are conducted in phases. The trials at each phase have a different purpose and help scientists answer different questions:

  • In Phase I trials, researchers test an experimental drug or treatment in a small group of people (20-80) for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
  • In Phase II trials, the experimental study drug or treatment is given to a larger group of people (100-300) to see if it is effective and to further evaluate its safety.
  • In Phase III trials, the experimental study drug or treatment is given to large groups of people (1,000-3,000) to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the experimental drug or treatment to be used safely. Fewer patients may be required when evaluating an investigational drug for a relatively rare disease.
  • In Phase IV trials, post marketing studies delineate additional information including the drug's risks, benefits, and optimal use.

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