Glossary Term

There are various terms related to clinical research, with which you may or may not be familiar. This section covers definitions of such terms.

Adverse Event A medical occurrence or a negative change that happens at the time of a clinical trial or within a specific period once the trial is completed, is termed as adverse event. It may or may not be caused by the treatment which is being studied.
Arm assignment Arm assignment is the assignment of a group or subgroup of participants of a clinical trial to get interventions or no interventions as specified in the protocol.
Assessment It is a procedure that is used to generate required data of a trial. For example: blood test and scan.
Blind It is a type of clinical trial design in which parties involved in the trial, like research team or a participant are not aware regarding which participant has got which treatment.
Control Control in clinical trial is also known as ‘standard’ treatment. The control treatment is compared with the investigational treatment to show that the approved treatment in the trial works efficiently.
Clinical study Clinical study is a research study which is conducted on human volunteers to get answers to specific health questions. The interventional studies help in determining the safety and efficacy of the experimental treatments or ne use of existing therapies, under controlled environments.
Cross-over trial A clinical trial in which groups of volunteers are administered with two or more interventions in a certain manner. For example, a ‘two-by-two’ cross-over trial design is the one in which one group receives drug X at the initial stage of the trial and later receives drug Y for the rest of the trial. While, in the second group, participants receive drug B first and later drug A. This is the reason why the term ‘cross-over’ is used for describing the order of their assignment.
Dosing discontinuation The point of time when a volunteer patient stops taking drugs permanently due to some reasons is termed as dosing discontinuation. It may happen at the end or before the end of a study.
Double-blind In double blind clinical trial design, only the study pharmacist is aware what study medications a participant is getting, while the participant, nurses, doctors and rest of the clinical trial staff is not informed.
Early patient withdrawal (premature withdrawal) It is the time when a patient leaves a trial before the planned completion of the trial or investigational drug administration and all the later procedures.
Eligibility Criteria The eligibility criteria in clinical study refers to the requirements that a participant must meet before volunteering for a trial. It includes both, the inclusion and the exclusion criteria as well. These requirements are defined in the protocol.
EMA EMA or European Medicines Agency, is the agency of the European Union that oversees the use of medicinal products. It is the regulatory authority of medicinal products in European Union.
Enrollment It is the time when a volunteer enters the trial, after informed consent has been received. It may also be used to define the number of participants in a clinical trial.
Health Authority It is an international and national authority which regulates the clinical study.
Indication A disease, symptom, or set of situations that make a specific test, medication, procedure, or surgery advisable. For a treatment, it refers to the use of that treatment in treating certain disease.
Informed consent Researchers use informed consent to explain the clinical trials to the volunteers. The main purpose of informed consent is to protect participants. It is used when somebody interested in participating first asks about the study and it continues throughout the study, until the study ends. The research team will review the details of the trial with the potential participant and will answer any questions. This information is also written in a document, known as the informed consent form, which is designed to be clear and easy to understand. If a person decides to enrol in a clinical trial, they will sign the informed consent form to acknowledge that they understand the details of the trial and consent to participating. The form of informed consent is not a contract form and the participant can withdraw at any time from the trial and for any reason.
Institutional Review Board (IRB or IEC) IRB is also known as an independent ethics committee (IEC), ethical review board (ERB) or research ethics board (REB)). It is a group of doctors, scientists, advocates, researchers, and members of the community which helps to review and monitor all research activities involving humans. The main purpose of IRB is to provide ethical oversight and to minimize the risk to participants.
Interventional Study It is also known as a clinical trial. It is a type of clinical study in which participants receive one or more interventions, according to the protocols of research. Also, Researchers can evaluate the effects of the intervention on a health condition.
Investigational Drug Investigational drug is the drug which being evaluated in the trial. It also includes “investigational new drug” or “investigational medicinal product.”
Medication Number Medication number is a unique number on the label of each investigational drug package that is used in a trial to track the medication effects. The main aim of the number is used to make sure the drug is supplied in the right quantities to different research centres.
Observational Study An observational study investigates health related issues among the groups of people during their everyday life at home, work, or the doctor’s office, where assignment of treatments or other procedures is as part of their regular medical check-up.
Outcome Measure In clinical trials, it is set of measurement that is described in the protocol and is used to evaluate the effect of an intervention on participants.
Part Part is a subdivision of a single protocol in major building blocks. These are often independent of each other and have different objectives or different groups of volunteers. For example, a single-dose design and a multiple-dose design can be incorporated into one protocol with to parts or the same could be used with different groups of patients with different severity of a disease.
Phase Phase in a clinical trial is the categories which is define by FDA to describe the clinical trial of a drug based on characteristics like objective and number of participants in the study. Mainly, there are four phases:
  • Phase I : This phase includes testing of an experimental drug, vaccine or device in a small group of people for evaluating the safety, side effects and determining the safe dosages.
  • Phase II : This involve a larger group of people than Phase I and are designed to assess whether the experimental treatment is safe and determines whether it will work or not. It can last several years.
  • Phase III :This phase involves large studies for comparing the experimental drug or vaccine to a placebo or standard treatment. This phase evaluates whether the drug works and collect information to allow it to be used safely.
  • Phase IV :This phase is performed once a drug has reached the market and is to provide additional information about the best use of the drug.
Placebo In clinical trial, placebos include the inactive substances and is made to look like the investigational treatment. It is sometimes used to compare against the actual investigational treatment for evaluating effectiveness.
Principal investigator Principal investigator is the person responsible for the scientific and technical direction of the clinical trial at a specific clinical site. Many times, principal investigator is the leading physician in the studied disease area.
Protocol A protocol is a study plan on which the trial is based. It defines the type of people that can and cannot participate in the clinical trial, schedules the tests, medications, procedures and administered dosages. It also defines the outcome measures to evaluate and length of study.
Randomized allocation It is a strategy in which participants are randomly assigned to study arms of a clinical trial by computer.
Randomization number It is a unique number assigned to each randomized patient that is used to identify individuals, but maintain anonymity, corresponding to a specific study arm assignment.
Run-in period Run-in period is the elapsed time before a trial starts, which is when no investigational drug is given to trial participants. During this the patients may still receive standard treatments for their disease if these treatments are allowed within the trial period.
Serious adverse event A serious adverse event is life-threatening and requires hospitalization or extended hospital stay, which results in ongoing or significant incapacity. It may cause congenital anomalies or birth defects or may even result in death.
Sponsor A sponsor is the organization, a person, or an institution that oversees the conduction of clinical trial and provides financial support as well.
Study completed date The study completed date is the date on which the last participant is made to visit the study location, where last samples are taken and last tests are performed.
Subject A subject is an individual, a volunteer participant whose responses to specific interventions are evaluated in a clinical trial. It is also referred to as trial participant.
Subject number It is a unique number that is assigned to each participant who enrols into a clinical trial.
Variable Variable is the information collected during a clinical trial from direct or indirect data. For example, one variable might be “weight,” which would then be checked at specified time points throughout the trial.
Wash-out period The period allowed for all the administered drug to be eliminated from the body.