Clinical Trial Glossary

Below is a list of some helpful terms you may hear as you begin to explore the clinical trial process.


Here are a few acronyms you may hear a lot:

  • NIH – National Institutes of Health
  • CDC – Centers for Disease Control
  • FDA – Food and Drug Administration
  • HHS – Department of Health and Human Services
  • NINDS – National Institute of Neurological Disorders and Stroke
  • NIAMS – National Institute of Arthritis and Musculoskeletal and Skin Diseases
  • NCATS – National Center for Advancing Translational Sciences

Adverse Event (AE)

An event that happens in a study to the patient while receiving the treatment/therapy.  It may or may not be caused by the treatment or therapy.


Children under the age of 18 are not legally able to provide informed consent. Instead, they are asked for their assent (meaning they agree to take part in the study). Assent is obtained in addition to parental/guardian informed consent. Assent is usually obtained from the ages of 7-17, but this does vary depending on the local IRB.


Typically some type of lab test or value that can be objectively measured and evaluated.  The biomarker can serve as an indicator of the normal biological process, disease process, or pharmacologic responses to a therapy/treatment. A biomarker in Duchenne could be dystrophin in a muscle biopsy or an MRI of a muscle. Right now there are no approved or “validated” biomarkers for Duchenne, but companies are using them in trials to add to the clinical evidence and hopefully have them validated over time.

Blinding of Study

At least one or more parties involved in the trial, such as the researcher or the people in the study, do not know which people have been assigned which treatment group.


In Duchenne, women who carry one copy of the genetic change that causes Duchenne or Becker. The woman also has another copy of the Dystrophin gene that does not contain the genetic change. Carriers have a 50% chance of passing the mutation on to each pregnancy.

Clinical Endpoint

Measure of events or outcomes such as symptoms, functional abilities, laboratory tests, etc., that help objectively determine if the therapy or medication is working.

Clinical Research

The study of health and illness in people. It can include things like the cause, prevention, diagnosis, treatment, or progression of a disease.

Clinical Trial Randomization

In a clinical trial, people are assigned by chance to separate groups that compare different treatments. A participant cannot choose which group to be in and neither can the researcher

Compassionate Use

See “Expanded Access”

Data Safety Monitoring Board (DSMB)

Group of experts that advises the study investigators about the study safety. They can make recommendations throughout the study that could affect whether the study continues or is modified or is stopped because of safety concerns.


Deoxyribonucleic acid (DNA) is the chemical inside the nucleus of all cells that carries the genetic instructions for making living organisms.

DNA Sequencing

A method of testing that is like proofreading a sentence. With DNA sequencing you determine the exact genetic code of the area you are studying. Different people can have slightly different sequences (variants) with little or no impact on how well the gene works. This is normal variation and is what makes us each unique.  However, some errors in a gene’s sequence can have serious consequences and cause diseases like Duchenne.

Double Blind Study

Two or more parties involved (such as the researcher and the person in the study) do not know which people have been assigned which treatment groups.

Exclusion Criteria

A list of things that exclude a patient from being in a study.

Expanded Access

A means by which companies can make investigational new drugs available, under certain circumstances, to treat a patient(s) with a serious disease or condition who cannot participate in a controlled clinical trial. FDA must approve the use, the company must be willing to supply the drug, and a treating physician must be willing to monitor the patient.


A gene is, in essence, a part or portion of DNA that gives the body instructions on how to make specific proteins such as dystrophin.


A person who has one copy of a gene with a genetic change.  Humans typically have two copies of most genes.  When you are a heterozygote for a particular gene change, it means one copy of your gene contains the gene change, while the other copy does not.

Inclusion Criteria

A list of features such as age, mobility status, disease state, etc., that must be met to be in a study.

Informed Consent

The voluntary permission from a person stating they are willing to be in a clinical trial. Before a person gives their consent, the study coordinator will review with them information about the trial, including what the study is trying to show (potential benefits, risks and inconveniences, alternative therapies available) and of the person’s rights and responsibilities.

Institutional Review Board (IRB)

An independent group of professionals designated to review and approve the study which includes the protocol, informed consent forms, study advertisements, and patient brochures.  The IRB’s job is to ensure that the study is safe and effective for anyone who will be in the study.  It is also the IRB’s responsibility to ensure that the study adheres to the FDA’s regulations.

The IRB is responsible for:

  • making sure the risks are as low as possible and that the risks are worth the benefits, and
  • making sure all federal, institutional, and ethical guidelines are followed.

The IRB must review and approve components of a study including:

  • the protocol
  • informed consent forms
  • study advertisements/recruitment materials
  • informative handouts (i.e. fact sheets or brochures).

Intermediate Clinical Endpoint (ICE)

A measure of a therapeutic effect that is considered reasonably likely to predict the clinical benefit of a drug.

Investigational New Drug (IND)

A drug that has not been approved for general use by the FDA, but is being studied in clinical trials to study its safety and effectiveness. The IND program at FDA is how a pharmaceutical company obtains permission to ship an experimental drug across state lines (usually to clinical investigators) before the drug has been approved. The FDA reviews the IND application for safety to assure that research subjects will not be subjected to unreasonable risk. If the application is cleared (accepted), the candidate drug usually enters a Phase 1 clinical trial.


A change in genetic material. Mutations can be passed down through families or can occur by accident in a person for the first time. A mutation changes how that gene is supposed to work.

Natural History Study

A study that follows a group of patients over time who have, or are at risk of developing, a specific medical condition or disease. A natural history study collects health information in order to understand how the medical condition or disease naturally develops and progresses.

New Drug Application (NDA)

The compiling of all non-clinical, clinical, pharmacological, pharmacokinetic, and stability information required about a drug by the FDA in order to approve the drug for marketing in the U.S.

Open Label Study

Everyone involved (i.e. people, doctors, pharmacists) in the trial know which people have been assigned which treatment group.

Outcome Measure

A test that is used to objectively determine the function of a patient. Common outcome measures in Duchenne are the 6-minute walk test (6MWT), North Star Ambulatory Assessment (NSAA), 10-meter walk/run. Non-ambulatory measures include reachable workspace and performance of upper limb (PUL).

Patient Reported Outcome (PRO)

Any report about a person and their health that comes directly from the person, without interpretation of that information by a clinician or anyone else. Examples include the surveys on DuchenneConnect that ask about symptoms, mobility, and quality of life.

Pharmacokinetics (PK)

The study of how a drug is processed, metabolized, and gotten rid of from the body.


Traits or characteristics that are observational such as brown hair or eye color.

The phenotype is determined by a person’s genetic makeup, or genotype. In Duchenne a phenotype trait could be scoliosis as it is an observable trait.

Pre-IND Meeting

Sponsors looking for pre-IND guidance can request a “Type B” meeting with the FDA.  This is an opportunity for a company to gain valuable feedback from the FDA on any questions regarding drug development. Although the FDA does not require these meetings, they are recommended because such meetings can confirm the requirements of the development process.

Primary Endpoint

The main event or outcome that is being used to determine if the therapy or treatment actually works.

Protocol Amendment

A written description of a change(s) to a protocol.

Secondary Endpoints

Secondary endpoints are only used to help interpret the primary endpoint, but they cannot be used by themselves to prove a therapy or treatment is effective. Secondary endpoints may also help provide information about future research.

Serious Adverse Event (SAE)

An event in a study that includes any of the following: (a) inpatient hospitalization or prolonging of a hospital stay, (b) significant disability, (c) death or life threatening event, (d) requires treatment to prevent permanent damage, or (e) results in a birth defect.

Single Blind Study

Either the researcher or the person in the study do not know which treatment group the person has been given.


The group, company, or individual who is paying for the clinical research. Sponsors include individual researchers, foundations, voluntary groups, health care institutions, government agencies, and pharmaceutical, biotechnology, and medical devices companies.

Study Protocol

The written description of a clinical study. It includes the study’s objectives, design, endpoints (or what is being measured), methods, inclusion, and exclusion criteria (who can participate).

Surrogate Endpoint

In clinical trials, a surrogate endpoint is an indicator or sign used in place of another to tell if a treatment works. Surrogate endpoints do not guarantee that a treatment works, but they can give an earlier indication that the therapy is reasonably likely to have benefit. Biomarkers can be used as surrogate endpoints (see biomarkers). In cancer, surrogate endpoints include a shrinking tumor. In Duchenne, though not yet validated, dystrophin levels or MRI imaging of muscle are exploratory surrogate endpoints.

X-linked disorder

The gene for the disease is located on the X chromosome. Males have one X chromosome and one Y chromosome. Females have two X chromosomes.