How Are Clinical Trial Participants Protected?

Several levels of safeguards are in place to help protect the people who take part in clinical trials. There are still risks involved with any study, but these safeguards try to reduce the risk as much as possible.

Three basic principles, as outlined in the Belmont Report from the late 1970s, provide the basis for research involving humans:

  • Respect for persons: Recognizing that all people should be respected and have the right to choose what treatments they receive
  • Beneficence: Protecting people from harm by maximizing benefits and minimizing risks
  • Justice: Trying to ensure that all people share the benefits and burdens of research equally

These principles are upheld by individuals and groups at the sites conducting research, and also by government agencies charged with overseeing clinical trials. A very important part of patient protection is the informed consent process, which is described in detail in What’s It Like to Be in a Clinical Trial?

Safeguards in institutions

Centers conducting clinical trials have committees that review all potential and ongoing clinical trials to protect the people in the studies. These reviews are required for all federally funded clinical trials, but even privately-sponsored studies must be reviewed.

Institutional review boards (IRBs)

Institutional review boards (IRBs) are groups of people responsible for protecting the welfare of the people who take part in the study and making sure that studies comply with federal laws. The boards are often made up of a mix of medical experts (like doctors and nurses), scientists, and non-medical people. Many institutions have their own IRBs, but some smaller centers may use larger, “central” IRBs. The federal Office of Human Research Protections (OHRP; see below) oversees the activities of IRBs.

Researchers who want to start a study must first submit the study protocol (the plan that describes the study in detail) to the IRB for review. The IRB must decide if the study is acceptable on medical, ethical, and legal grounds. In other words, does the study address a worthwhile question, and is it doing so in a way that ensures the safety of those taking part as much as possible?

One of the most important jobs of an IRB is to make sure the informed consent form that people entering the study must sign is accurate, complete, and easy to understand. Once a study begins, the IRB also follows its progress regularly to look for potential problems.

If you take part in a clinical trial, you can contact the study’s IRB directly with any questions or concerns regarding safety.

Data safety monitoring boards (DSMBs)

Data safety monitoring boards (DSMBs) are used for phase III (and some earlier phase) studies. They are committees made up of doctors and other scientists not involved in the study. Their job is to look at study statistics. They monitor the results of the clinical trial at different time points and can stop a study early (before all of the intended participants have been enrolled or before the study has been completed) if:

  • It becomes clear that the new treatment is much more (or much less) effective, so as to allow all study participants to get the better treatment
  • Safety concerns arise (such as risks of the new treatment clearly outweighing the benefits), so that no more people are exposed to possible harm

The clinical investigator

The clinical investigator is in charge of all aspects of a particular study. Most often the clinical investigator is a doctor; in some settings this person is called the principal investigator, or PI. Ultimately, the responsibility for patient safety in a clinical trial lies with the clinical investigator. Part of this responsibility is letting the study sponsor know right away when serious side effects occur.

Many clinical investigators have years of experience in running clinical trials. Their credentials are submitted to the FDA along with the investigational new drug application before the study is approved.

Government agencies

Several government agencies play roles in ensuring that all research is conducted with patient safety in mind. These include:

Office of Human Research Protections

In 2000, the Office of Human Research Protections (OHRP) was set up as the government’s main guardian of people’s safety and welfare in clinical trials. It enforces the rules regarding the informed consent process, institutional review boards (IRBs), and the participation of people with special needs in clinical trials, such as children and those with mental disabilities. It can suspend research activities until identified problems are corrected.

The OHRP also educates research centers and individuals to help them comply with current clinical trials standards.

Food and Drug Administration

The Food and Drug Administration (FDA) has the final say about whether or not a new treatment is approved to be given to patients. Once phase III clinical trials on a new treatment are completed, the FDA reviews the information and decides if it’s safe and effective enough to be approved.

But the FDA’s role in many clinical trials starts long before this. Any sponsor seeking approval for a new treatment must submit all study protocols to the FDA before the clinical trials are allowed to begin.

The FDA also inspects (audits) sites conducting clinical trials, especially if there’s reason to think they’re not following proper procedures. If serious problems are found, the FDA can forbid a particular site or doctor from doing any further research.

But the authority of the FDA is not absolute. Clinical trials that study treatments that are already on the market are not subject to the same FDA regulations (although many are still done in much the same way). And substances considered to be “dietary supplements” do not need FDA approval to be sold in the first place. (Dietary supplement makers aren’t required to prove that their products are safe or effective, so they usually don’t bother to conduct clinical trials.)

National Cancer Institute

The National Cancer Institute (NCI), part of the National Institutes of Health (NIH), sponsors many of the cancer clinical trials going on at any one time, including those done by cooperative groups. Proposals for such studies must be approved by the NCI before funding is granted. The NCI also regularly audits each site involved in NCI-sponsored research.

The American Cancer Society medical and editorial content team
Our team is made up of doctors and master’s-prepared nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

National Cancer Institute. Patient Safety in Clinical Trials. Accessed at on May 2, 2016.

US Department Health & Human Services. OHRP History. Accessed at on May 3, 2016.

US Department of Health, Education, and Welfare. The Belmont Report: Ethical Principles and Guidelines for the protection of human subjects of research, 1979. Accessed at on September 23, 2014.

Last Medical Review: May 3, 2016 Last Revised: May 3, 2016