Clinical trial definitions glossary and abbreviations

Accrual rate

The rate at which patients/volunteers enroll in clinical trials

Adverse Event


An adverse event is an undesirable and unintended incident linked to the utilization of a medical product, including drugs, vaccines, or medical devices. These occurrences vary from mild side effects to more serious reactions. They may or may not be associated with the intended use of the product. Adverse events can manifest during medical treatment or as part of a clinical trial. Monitoring and reporting of adverse events are crucial in healthcare and clinical research.

Assay development

Investigative procedures that qualitatively and/or quantitavily assess a compound or examine a compound’s effects on identified molecular, cellular, or biochemical targets.



Y-shaped protective protein produced by the immune system in response to the prescence of a foreign substance such as a bacteria. Antibodies recognize and latch onto foreign substances in order to remove them from the body.


A term used in radiology for off-target tissue. Or otherwise referred to as healthy tissue.

Blind Study


A clinical trial in which the participants (single-blind study) or the researchers (double-blind study) are unaware of treatment assignments or other specific information to reduce bias. This may involve withholding information about whether the treatment or placebo is given, to reduce bias and accurately evaluate the treatment.

Case Report Form


Central Drugs Standard Control Organisation


Centrale Commisie Mensgebonden Onderzoek


Dutch central committee that reviews and approves research involving human subjects

Chemistry Manufacturing and Controls


Clinical Trial Application


A CTA provides comprehensive information about the investigational medicinal product(s) and planned trial, enabling regulatory authorities to assess the acceptability of conducting the study.

Clinical Trials

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Clinical Trials Information System


Clinical Trials Regulation (EU)


Competent Authority


Concomitant Medication


Concomitant medication refers to drugs administered or treatments that are taken alongside the clinical study. These additional medications are often prescribed to manage side effects, enhance the primary treatment’s effectiveness, or address other health conditions the individual may have.

Confidential Disclosure Agreement


A legal document that protects proprietary information and binds the signed parties to keep information confidential for a set period of time.

Consolidated Standards For Reporting Trials


Contract Development and Manufacturing Organization


A company that serves pharmaceutical companies on a contract basis with services related to drug manufacturing and drug development.

Contract Research Organization


A company that provides support to the pharmaceutical, biotechnology, and medical device industries in the form of research services outsourced on a contract basis. Companies like TRACER.

Control Group


The comparison group comprises participants who do not undergo the experimental treatment, serving as a reference for evaluating the effects of the treatment group.

Current Good Manufacturing Practice


Data Safety Monitoring Board


A Data Safety Monitoring Board (DSMB) is a group of independent individuals, external to the trial, who are experts in relevant areas. They review the accumulated data from one or more ongoing clinical trials on a regular basis and advise the sponsor about the continued safety of the trial participants.

Decentralized clinical trials

Studies executed through telemedicine and mobile/local healthcare providers, using processes and technologies differing from the traditional clinical trial model.


Methods or systems to aid in the diagnosis or detection of a disease or cause of a problem.

Double-Blind Study


A type of clinical trial in which both participants and researchers are unaware of the treatment assignments and other specific information that may lead to biased results.

Drug target

A molecule in the body, usually a protein, that is intrinsically associated with a particular disease process and that could be addressed/targeted by a drug to produce a desired therapeutic effect.

Dutch Clinical Research Foundation


Emergency Investigational New Drug


Ethics Committee


EU Clinical Trials Directive


European Database on Medical Devices


European Medicines Agency


A decentralised agency of the European Union (EU) responsible for the scientific evaluation, supervision and safety monitoring of medicines in the EU.

Ex vivo

Experimentation or measurements done in or on tissue from an organism in an external environment/outside of the organism with minimal alteration of natural conditions

exploratory Investigational New Drug


Fluorescent labelling

The labeling of a drug/compound with a fluorescent

Food and Drug Administration


An American agency responsible for protecting the public health by ensuring the safety, efficacy, and security of human and veterinary drugs, biological products, and medical devices; and by ensuring the safety of our nation’s food supply, cosmetics, and products that emit radiation.



Good Clinical Practice


Good Laboratory Practice


The experimental (non-clinical) research arena, good laboratory practice or GLP is a quality system of management controls for research laboratories and organizations to ensure the uniformity, consistency, reliability, reproducibility, quality, and integrity of products in development for human or animal health (including pharmaceuticals) through non-clinical safety tests.

Good Manufacturing Practices


A system that describes the quality standard that pharmaceutical manufacturers must meet in their production processes. It is designed to minimize the risks involved in any pharmaceutical production that cannot be eliminated through testing the final product.

Guidance For Industry


Health Authority


The U.S. Department of Health and Human Services


Hazard Ratio


Image guided surgery


Image guided surgery systems use cameras or electromagnetic fields to capture and relay the patient’s anatomy and the surgeon’s precise movements in relation to the patient, to computer monitors in the operating room. These sophisticated computerized systems are used before and during surgery to help orient the surgeon with three-dimensional images of the patient’s anatomy including the tumor.





In situ

It lies somewhere between in vivo and in vitro. Something that’s performed in situ means that it’s observed in its natural context, but outside of a living organism.

In vitro

When something is performed in vitro, it takes place in a test tube, culture dish, or elsewhere outside a living organism.

In Vitro Diagnostics


In Vitro Diagnostic Regulation


In vivo

work that’s performed in or on a whole living organism such as a person, laboratory animal, or plant.

Independent Ethics Committee


Informed Consent


Informed consent is a process in which a person, typically a patient or research participant, is provided with clear and comprehensive information about a medical procedure, treatment, or research study. It is a fundamental ethical and legal requirement in medical practice and research.

Informed Consent Form


International Classification of Functioning, Disability and Health



Work that would otherwise have been contracted out is performed in house with the company’s own resources.

Intention To Treat


Investigation Medical Device


An Investigational Medical Device is a device that is currently under clinical investigation, typically as part of a clinical trial/study.

Investigational Medicinal Product


An Investigational Medicinal Product (IMP) refers to a pharmaceutical product (such as a drug or vaccine) that is being tested or investigated in a clinical trial. The term is commonly used in the context of medical research and drug development. Before a medicinal product is approved for use, it is tested in clinical trials to assess its safety, efficacy, and potential side effects.

Investigational new drug


A request from a clinical study sponsor to obtain authorization from the FDA to administer an investigational drug or biological product to humans.

Investigational Product


Investigational Review Board


Investigator Initiation Packages




Joint-Sponsors are two or more organizations or entities that collaborate and share responsibilities and interests in a study.


Kinetics in clinical studies refers to the study of drug absorption, distribution, metabolism, and excretion over time, influencing dosing regimens and therapeutic outcomes.

Longitudinal Study


A research study that observes and collects data from particular individual participants over an extended period of time.

Medical Research Council


Medicines and Healthcare products Regulatory Agency




Molecules that caries genetic material with a set of instructions. These instructions direct cells in the body to make proteins .


Microdosing, or micro-dosing, is a technique for studying the behaviour of drugs in humans through the administration of doses so low (“sub-therapeutic”) they are unlikely to produce whole-body effects, but high enough to allow the cellular response to be studied. This is called a “Phase 0 study” and is usually conducted before clinical Phase I to predict whether a drug is viable for the next phase of testing. Human microdosing aims to reduce the resources spent on non-viable drugs and the amount of testing done on animals.


A part of a molecule that is given a name because it is identified as a part in other molecules as well

Molecular imaging

Molecular imaging is a type of medical imaging that provides detailed pictures of what is happening inside the body at the molecular and cellular level.


A small particle that ranges between 1 to 100 nanometres in size.


Near-infrared is the region closest in wavelength to the radiation detectable by the human eye. Light within the wavenumber range of 12,500 to 4,000 cm-1 (wavelengths from 800 to 2,500 nm)

New Molecular Entity


A chemically unique pharmaceutical that has not previously been approved by the FDA.

Notified Body


Nuclear labeling

The labeling of a drug/compound with a radionuclide

Nuclear molecular imaging

An imaging method that uses very small amounts of radioactive materials (radiopharmaceuticals) to diagnose and/or treat disease. In nuclear medicine imaging, the radiopharmaceuticals are detected by special types of cameras that work with computers to provide very precise pictures of the area of the body where the radiopharmaceuticals are taken up.

Off-target tissue

Tissue that does not express the drugs’ target of interest, i.e. healthy tissue.

On-target tissue

Tissue in which the disease is present such as cancer cells/tumors

Oncologic Drugs Advisory Committee (FDA)


Optical fluorescent molecular imaging

An imaging technique using fluorescent light to visualizes the cellular and biological function in a non-invasive fashion to better understand in vivo disease processes and treatment effects.

Optical molecular imaging

An imaging method that uses light and special properties of photons to obtain detailed images of organs, tissues, cells and even molecules. The techniques offer minimally or non-invasive methods for looking inside the body.

Optoacoustic imaging

Optoacoustic imaging is able to detect, track and monitor the behaviour of molecules under physiological conditions, often without the use of a contrast agent. (A medical imaging modality that uses light and sound waves to generate images of tissue structures based on light absorption within a tissue sample.)


Hiring an outside supplier to complete, produce or execute specific services or goods.

Patient Information File (PIF)


A document stating information about the goal of the study, participation requirements and other relevant details about the clinical trial which patients/volunteers get to review before participating in the study.


A short strings of amino acids, typically comprising 2–50 amino acids. Amino acids are also the building blocks of proteins, but proteins contain more amino acids.

Per Protocol


Peripheral Arterial Occlusive Disease


This medical term refers to a condition characterized by the narrowing or blockage of the arteries, usually in the legs. It can lead to reduced blood flow to the extremities, causing symptoms such as pain, cramping, and difficulty walking.

Phase I, II and III clinical trials

Clinical trials are research studies performed in humans that are aimed at evaluating a medical, surgical, or behavioral intervention. They are the primary way that researchers find out if a new treatment, like a new drug or diet or medical device (for example, a pacemaker) is safe and effective in people.

Placebo Effect

The phenomenon where participants in a study experience perceived improvements in their condition while they don’t receive the experimental treatment but a placebo instead.

Positron emission tomography (PET)-scan


An imaging method that helps reveal how your tissues and organs are functioning. It uses a radioactive drug (tracer) to show this activity.


Preclinical studies take place before any testing in humans is done. Such studies involve in vitro (test tube or cell culture) and in vivo (animal model) experiments using wide-ranging doses of the drug, procedure, or treatment to obtain preliminary efficacy, toxicity and pharmacokinetic information. Such tests assist the developer to decide whether a drug candidate has scientific merit for further development as an investigational new drug.


Also called personalized medicine, is a medical approach that evaltuates the genetics, environment, and lifestyle of a person in order to select treatment that could work best for the individual patient.

Principal Investigator


The principal investigator (PI) is the lead researcher or scientist in charge of a particular research project.

Probability of technical and regulatory success


The chance of succes of a clinical trial and the subsequent regulatory approval

Proof of Concept (PoC study)


Also called phase 0 studies, are performed prior to Phase I studies and include a small number of patients (n=10-20) with the disease of interest. They are executed to optimize the R&D sweet spot.


A naturally occurring, complex substance that consists of thousands of smaller units called amino acid residues which are attached to one another in long chains.The chains of amino acid interacts with each other to form a 3-dimensional structure

quality management system


Quality System Regulation (FDA, 21 CFR Part 820, CGMP)


Quick win, fast fail

An alternative to the traditional development method that shifts the proof of concept (POC) stage from Phase II to just after the start of clinical development. You quicly know if your compound is succesful (win) or not (fail).

R&D sweet spot

The period between pre-clinical and Phase I development in which you conduct a Proof of Concept (POC) study.

Randomized Controlled Clinical Trial


Regenerative Medicine Advanced Therapy


Return on Investment


A performance measure to evaluate the amount of return on a particular investment, relative to the investment’s cost.

Serious Adverse Event


A Serious Adverse Event (SAE) is an Adverse Event (AE) but with a more severe outcome. In the context of clinical trials, SAEs are events that result in death, life-threatening situations, (extended) hospitalization, disability or incapacity, or congenital anomaly or birth defect.

single Investigational Review Board


Site Activation Partner


Site Relationship Partner



A process in radiology of determining the extent to which a cancer has developed by growing and spreading. It helps to direct treatment and aid prognosis

Standard Operating Procedure


Documented processes that a company has in place to ensure services and/or products are delivered consistently every time while meeting minimum quality standards.

Sub-therapeutic / non-pharmacologically

Indicating a dosage of a drug or vitamin that does not have a therapeutic effect.


A medicine or therapy that cures disease or relieves pain.


A research strategy that involves using multiple methods or data sources and/or researchers to improve validity and credibility of research findings.

Unexpected Adverse Reaction


An adverse event that was not anticipated on based on the known safety profile.

Universal Trial Number


The Universal Trial Number from the WHO (WHO UTN) is an identification number that is obtained early in the proces and becomes permantly attached to the trial.

Urgent Safety Measure


In the case of an unexpected event that significantly affects the benefit-risk balance, the sponsor and investigator should take USM(s). For EU clinical trials both the event and the USM(s) need to be registered in CTIS. The MSc should be notified of any USM in an ongoing study. The USM can then result in a substantial modification of protocol or procedures.


Validity in clinical research refers to the extent to which obtained measurements and data can be perceived as valid, meaning that the study findings and conclusions are useful, reliable, credible, and accurate.

Women s Health Initiative


World Health Organization


Agency of the United Nations (UN) that acts as a global authority on health matters. The organization establishes rules, guidelines, frameworks, methodologies, and ethical considerations that affect clinical trials worldwide.


Electromagnetic radiation is used in medical imaging to visualize the internal structures of the body. X-ray is a form of high energy radiation that can pass through tissues. Ideal for imaging of bones, but less useable for imaging of softer tissue. X-ray cannot be used to image pharmacological processes in the body.

Yellow Card Scheme


The YCS is a pharmacovigilance system that collates suspected Adverse Drug Reactions (ADRs) of drugs already on the market. It has existed since 1964 and is currently run by the Medicines and Healthcare Products Regulatory Agency (MHRA). This in the UK used system is similar to EudraVigilance used within the EU except that EudraVigilance is used for both drugs on the market and in clinical trials.

Zero dose control

Zero dose control refers to the control group that receives no dose of the investigated compound. This can be in fixed-dose / dose-response trials. In a blind study where participants or researchers don’t know if an active dose is administered to the subject, the zero dose is a placebo. In a non-blind study, the zero dose is different from a placebo since no treatment nor a placebo is given.