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Participating in clinical research

Key points

There are two kinds of clinical research: observational studies collect participant data without any intervention while clinical trials actively test medicines, medical devices, or other interventions.
All clinical research must be reviewed and approved by an institutional review board (IRB) to make sure the study design is ethical and safeguards patients, their information, and their privacy.
Participating in clinical research studies is always voluntary and you have the right to drop out of any study at any time for any reason.
The U.S. Food and Drug Administration (FDA) uses clinical trial data to determine if new preventions, treatments, and diagnostics should be approved for widespread use.

People with primary immunodeficiency (PI) or their caregivers may have the opportunity to join clinical research studies. Clinical research is any research study involving human subjects [1]. There are two broad types of clinical research:

Some studies only collect data or information as participants go about their daily lives. These are called observational studies. Examples include:
- Natural history studies that collect data on how a condition develops and changes over time.
- Studies that look at specific biological or environmental factors in one group of people versus another.
Some studies actively test medicines, medical devices, or other interventions. An intervention is anything that changes the study participant or their surroundings. These types of studies are called clinical trials. Their purpose is to test an intervention in humans to see if it is safe and if it can prevent, diagnose, treat, or help manage a medical condition. Clinicaltrials.gov lists all clinical trials in the U.S., as well as many international clinical trials.

Both observational studies and clinical trials are important for advancing medical knowledge and improving patient care. In many cases, observational studies help researchers develop interventions that are later tested in clinical trials.

Clinical research protections and safeguards

All research involving human subjects must meet a set of international ethical and safety standards first established by the Nuremberg Code in 1947 [2]. Institutional review boards, known as IRBs, make sure studies follow these ethical standards, prioritize patient safety by ensuring risks do not outweigh possible benefits, and protect patient privacy and health information. IRBs also make sure that study plans address concerns for special populations such as children or pregnant women, if applicable. All clinical research must be approved by an IRB before studies begin recruiting participants.

Oversight

There are also federal government agencies that oversee clinical research done in the U.S.

The Office of Human Research Protections (OHRP) within the U.S. Department of Health and Human Services (HSS) [3] oversees all clinical research funded by HHS agencies, whether at the agency itself or at outside institutions.
The U.S. Food and Drug Administration (FDA) [4] oversees clinical trials. All clinical trial sponsors must follow FDA’s rules for human research.

Informed consent

Before enrolling in observational studies or clinical trials, researchers will ask you to sign a form called informed consent. Informed consent describes, in detail, what the study is about, what you need to do or not do if you participate, the potential risks and benefits of participating, and any payment or free medical care you will receive. Signing this form means that you understand the risk and benefits and agree to be part of the study. Participation in a clinical research study is entirely voluntary and only begins after you give your informed consent.

Everyone participating in clinical research, or their parent or guardian if the participant is a child, has to sign an informed consent form. For children participating in clinical research, many centers also use an assent document. This age-appropriate document details what the child should expect as a participant in the study. The age of assent varies by hospital or institution but generally starts at 10 years of age.

Informed consent is an ongoing process. Researchers will update you if there are any changes in the study or new findings that may affect your willingness to continue participating. You have the right to withdraw your consent and stop participating at any time for any reason.

Privacy protections

You also have the right to privacy if you choose to participate in clinical research. The Health Insurance Portability and Accountability Act (HIPAA) applies to observational studies and clinical trials and protects your personal health information [5]. A study’s informed consent form will outline who has access to your information, which may include study sponsors and other researchers working with study staff. Note that study staff cannot share your health information with anyone else without your consent unless it has been de-identified, which means stripped of anything that can identify you as an individual like your name or date of birth.

Important considerations for participating in clinical research

Why is the clinical research being done, what is being tested or evaluated and who is conducting and paying for the study?
What would your participation include, such as how many visits are required, additional testing, or imaging, and where will you need to go to participate?
Will your participation affect your health insurance or life insurance coverage?

In addition to the questions above, OHRP has a list of questions to ask the study sponsors and researchers if you are considering participating in clinical research.

As a study participant, you have rights. This includes the right to withdraw your consent and stop participating in the study at any time without any consequences to your existing care or relationship with your provider.

Types of clinical research

Human testing in clinical trials helps researchers develop safe interventions that have acceptable side effects while providing the greatest patient benefit. Interventions can include:

Something meant to prevent a disorder or disease from developing or returning, such as medicines, vitamins, vaccines, or lifestyle changes. Example: using a new antifungal to prevent infections.
A device, test, or method for screening for or diagnosing a particular disorder. Example: using sequencing for newborn screening for PI.
Treatment or supportive care for a disorder or related symptoms, such as medicines, medical devices, procedures, or lifestyle changes. Example: gene therapy for PI.

Before researchers do clinical trials in humans, they study an intervention either in laboratory animals or with laboratory-grown human cells, or they collect observational study data to show that the intervention is safe to directly test in humans. These preclinical studies must show some positive outcomes and safety before clinical trials can begin in humans.

To make sure that an intervention will work for different people, it is important that clinical trial participants are from different ages, genders, and racial and ethnic groups. Ideally, the demographics of trial participants should match the demographics of the larger pool of people that will use the intervention. Demographically diverse trials help researchers identify any groups that do not benefit from the intervention and any groups that have a higher risk for side effects. However, clinical trials are often done first with low-risk populations or healthy volunteers, unless the intervention is specifically designed for a higher risk population.

Clinical trials are the last research and development step before an intervention can be submitted to the FDA for approval. Certain types of interventions, such as new medicines or medical devices, must be approved by the FDA to be made widely available to people in the U.S. Development of interventions that need FDA approval can take 10-15 years. Many proposed interventions don’t make it to the clinical trial phase or are found to be ineffective or unsafe during the clinical trial process.

Clinical trials are done in a step-by-step manner called phase(s). Each phase of the process must be safely completed before the next phase begins.

Phase I trials

Phase I clinical trials test an intervention in a small group of people, usually for the first time in humans. The goal is to test safety and identify possible side effects. Phase I trials may be done in a group of healthy individuals depending on the intervention being studied.

Phase II trials

During phase II clinical trials, the intervention is given to a larger group of people affected by or who could develop the medical condition the intervention is supposed to prevent, diagnose, or treat. The goal is to get initial data on how well the intervention works and determine the best dose(s), if applicable.

Phase III trials

Researchers give the intervention to an even larger group of individuals with or who could develop the medical condition to prove that it works and to monitor for side effects. Phase III trials are typically the final step before the FDA considers whether to approve an intervention. These trials often compare the intervention to the standard treatment or prevention for the condition to test how well it works.

Phase IV trials

These trials are for interventions that have been approved by the FDA. Phase IV studies, also known as postmarketing or post-approval studies, are designed to get additional, long-term safety and effectiveness information as people use the intervention in the real world. Sometimes these studies are required by the FDA, especially if the intervention has gone through the accelerated approval program [6].

Participating in clinical trials

Participation in clinical trials may allow you to benefit from specialized healthcare or access to interventions that are not otherwise available. However, there are possible risks as well as benefits that you should carefully consider and discuss with your healthcare providers. Make sure you fully understand the possible benefits and risks of participating before making your decision.

Participating in some clinical trials may prevent you from participating in other trials at a later time. There are often specific factors that make someone ineligible for a trial, especially if you have received a previous investigational drug or therapy. You should discuss this with the study team.

Deciding to take part in clinical trials is something only you can decide once you have information about the study from the study sponsor and research team. Make sure you consider the following risks.

Intervention is not effective

There is always a chance the intervention being tested will not work.

Unknown side effects and risks

Known side effects will be described in the informed consent document. However, there may be other side effects or health risks that are not known by the study team at the time you start the study, especially in early stage trials.

Randomization, placebos, and blinding

Randomization, placebos, and blinding are strategies used in some clinical trials to prevent bias in the results.

In a randomized trial, one group (the test group) receives the study intervention. Another group (the control group) receives either the most widely accepted standard intervention for the condition being studied or no intervention at all if there is no standard intervention available. For example, the test group in a clinical trial might receive a new immunoglobulin (Ig) product while the control group receives an Ig product that is already FDA approved. Comparing the results from the test and control groups shows whether the study intervention is more effective and/or has fewer side effects than the intervention(s) that is already available.

Usually, a study statistician or pharmacist randomly assigns participants to test or control groups. Before you decide to participate, you should understand that your chance of being randomized into the test or control group is about equal, like the flip of a coin.

Trials often use blinding with randomization. Blinding means that neither you, your healthcare providers, nor the study researchers collecting data know if you are getting the test intervention or not.

To prevent trial participants and the researchers from guessing who is receiving the study intervention, some randomized clinical trials testing medications use placebos. Placebos are inactive ‘look-alike’ medicines given to the control group when there is no standard intervention that can be used. In a placebo study, there is the possibility that you will not be selected to receive the test medicine and will not know this until later in the trial.

References

1. Frequently Asked Questions: NIH Clinical Trial Definition. In: National Institutes of Health Office of Intramural Research [Internet]. [cited 23 Oct 2025]. Available:https://grants.nih.gov/faqs#/clinical-trial-definition.htm
2. Ethics in Clinical Research. In: National Institutes of Health Clinical Center [Internet]. [cited 23 Oct 2025]. Available: https://www.cc.nih.gov/recruit/ethics
3. Department of Health and Human Services. Office for Human Research Protections. 4 Mar 2022 [cited 23 Oct 2025]. Available:https://www.hhs.gov/ohrp/index.html
4. Clinical Trials and Human Subject Protection. In: Food and Drug Administration [Internet]. FDA; 4 Jun 2024 [cited 23 Oct 2025]. Available: https://www.fda.gov/science-research/science-and-research-special-topics/clinical-trials-and-human-subject-protection
5. Department of Health and Human Services. Special Topics - Research. In: Health Information Privacy [Internet]. [cited 23 Oct 2025]. Available: https://www.hhs.gov/hipaa/for-professionals/special-topics/research/index.html
6. Accelerated Approval Program. In: Food and Drug Administration [Internet]. FDA; 17 Oct 2025 [cited 23 Oct 2025]. Available:https://www.fda.gov/drugs/nda-and-bla-approvals/accelerated-approval-program

Organizations that connect people to research

ResearchMatch

ResearchMatch is made up of volunteers, researchers, and community collaborators working together to make it easy for you to find the right clinical trial or research study for you or your family.

ResearchMatch.org

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This page contains general medical and/or legal information that cannot be applied safely to any individual case. Medical and/or legal knowledge and practice can change rapidly. Therefore, this page should not be used as a substitute for professional medical and/or legal advice. Additionally, links to other resources and websites are shared for informational purposes only and should not be considered an endorsement by the Immune Deficiency Foundation.

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Participating in clinical research

Key points

Be part of MIRACLE

Clinical research protections and safeguards

Oversight

Informed consent

Privacy protections

Important considerations for participating in clinical research

Types of clinical research

Phase I trials

Phase II trials

Phase III trials

Phase IV trials