Clinical Trials
Clinical Trials

Clinical Trials Benefits, Risks, and Safety Measures

Clinical trials offer hope for many people while giving researchers a chance to find treatments that could benefit patients in the future. Healthy volunteers say they take part to help others and contribute to moving science forward. People with an illness or disease may take part to help others but also to have a chance to receive the newest treatment and get added care and attention from the clinical trial staff.

Clinical trials may involve risk, as can routine medical care and the activities of daily living. When weighing the risks of clinical trials, consider the possible harms that could result from taking part in the study, the level of harm, and the chance of any harm occurring.

Possible benefits

  • Well-designed and well-performed clinical trials provide benefits to you while allowing you to help others by contributing to knowledge about new treatments or procedures.
  • You gain access to new research treatments before they are widely available.
  • You receive regular and careful medical attention from a research team that includes doctors and other healthcare professionals.

Possible risks

Clinical trials do come with some risks.

  • Most clinical trials pose the risk of minor discomfort, which often lasts only a short time. However, some study participants experience complications that require medical attention. In rare cases, participants have experienced serious or life-threatening complications resulting from their participation in trials of experimental treatments.
  • The study may require more time and attention than standard treatment would, including visits to the study site, more blood tests, more procedures, hospital stays, or complex dosage schedules.

In clinical trials that compare a new product or therapy with another that already exists, researchers try to determine whether the new one is at least as good as the existing one. In some studies, you may receive a placebo. Comparing a new product with a placebo can be the fastest and most reliable way to show the new product’s effectiveness. However, placebos are not used if you would be put at risk — particularly in the study of treatments for serious illnesses — by not having effective therapy. You will be told if placebos are used in the study before you enter a trial.

You can learn about the risks and benefits of any clinical trial and how your rights are protected before you agree to take part in the trial. A member of the research team will explain the study and answer any questions you have about the study. A member of the research team will also ask you to consider and sign an informed consent document, which will describe in detail the specific risks associated with a research protocol. Before deciding to participate, carefully consider risks and possible benefits. You can also talk with your doctor about specific clinical trials you are interested in.

Questions to ask your doctor and the research staff

If you are thinking about taking part in a clinical trial, you should feel free to ask any questions or bring up any issues concerning the trial at any time. The following suggestions may give you some ideas as you think about your own questions.

The study

  • What is the purpose of the study?
  • Why do researchers think the approach may be effective?
  • Who will fund the study?
  • Who has reviewed and approved the study?
  • How are study results and safety of participants being monitored?
  • How long will the study last?
  • What will my responsibilities be if I take part?
  • Who will tell me about the results of the study, and how will I be informed?

Possible benefits and risks

  • What are my possible short-term benefits?
  • What are my possible long-term benefits?
  • What are my short-term risks and possible side effects?
  • What are my long-term risks?
  • What other options are available?
  • How do the risks and possible benefits of this trial compare with those options?

Participation and care

  • What kinds of therapies, procedures, and/or tests will I have during the trial?
  • Will they hurt, and if so, for how long?
  • How do the tests in the study compare with those I would have outside of the trial?
  • Will I be able to take my regular medicines while taking part in the clinical trial?
  • Where will I have my medical care?
  • Who will be in charge of my care?

Personal issues

  • How could being in this study affect my daily life?
  • How might the study affect my family?
  • Can I talk to other people in the study?

Cost issues

  • Will I have to pay for any part of the trial, such as tests or the study medicine?
  • If so, what will the charges likely be?
  • What is my health insurance likely to cover?

Protecting the safety of people who take part in clinical trials is a high priority for the NHLBI and its researchers. You also have rights to help protect your safety.

Scientific oversight

Each study has scientific oversight, including the following:

  • An Institutional Review Board (IRB) approves and monitors most, but not all, of the clinical trials in the United States to ensure that the risks are minimal compared with the potential benefits. An IRB is an independent committee that consists of physicians, statisticians, and members of the community who ensure that clinical trials are ethical and that the rights of participants are protected. You should ask the research coordinator whether an IRB reviewed the research in which you are considering participating.
  • The Office for Human Research Protections (OHRP), part of the U.S. Department of Health and Human Services (HHS), oversees all research done or supported by HHS. The OHRP helps protect the rights, welfare, and well-being of healthy volunteers and patient participants. The OHRP provides guidance and oversight to the IRBs, develops educational programs and materials, and offers advice on research-related issues.
  • A Data and Safety Monitoring Board (DSMB) reviews data from a clinical trial for safety problems or differences in results among different groups. Many clinical trials supported or conducted by NIH are required to have a DSMB. This board consists of a group of research and study topic experts. A DSMB also reviews research results from other relevant studies. Scientific oversight informs decisions about a study while it is underway. For example, researchers stop some studies early if the benefits from a strategy or treatment are obvious, to make wider access to the new strategy available sooner. Researchers also may stop a study — or part of a study — early if the intervention or treatment is having harmful effects.
  • The Food and Drug Administration (FDA) provides oversight for clinical trials that are testing new medicines or medical devices. The FDA reviews applications for new medicines and devices before studies begin with human volunteers. The FDA checks to make sure that the proposed studies have followed proper informed consent and protection procedures. The FDA also provides oversight and guidance at various stages throughout the studies. For example, before Phase III trials begin, the FDA provides input on how these studies should be done.

Patient rights

As a participant in a clinical trial, you have rights that help protect your safety.

  • Informed consent is the process of learning the key facts about a clinical trial before deciding whether to participate. The process of providing information to participants continues throughout the study. To help you decide whether to take part, members of the research team explain the study. The research team provides an informed consent document, which includes such details about the study as its purpose, its duration, required procedures, and whom to contact for various purposes. The informed consent document also explains risks and potential benefits. If you decide to enroll in the trial, you will need to sign the informed consent document. You can withdraw from the study at any time.
  • Legal consent is required for children age 18 and younger, who get special protection as research participants. Almost always, a parent must give legal consent for the child to take part in a clinical trial. Sometimes, both parents must give permission for their child to enroll. Also, children age 7 and older often must agree to take part in clinical trials.

Participate in an NHLBI clinical trial

Search our list of research studies by topic, location, and age to see whether you or someone you know is eligible to join.

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