Eisai Clinical Trials


Terms are organised in alphabetical order. The definitions provided are to explain terms used in Eisai Clinical Trials only.

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Adverse event (AE)

An adverse event is a medical problem that may or may not be caused by the trial drug.


A group of participants receiving specific treatment, or receiving no treatment.


One or more parties involved do not know which subjects involved have been assigned to which intervention. This is to reduce or eliminate bias. Types of blinding include Open label and Double blind.

Clinical trial (Interventional study)

A clinical study in which participants are assigned to receive one or more interventions (or no intervention) so that researchers can evaluate the effects of the interventions on biomedical or health-related outcomes. The assignments are determined by the study protocol. Participants may receive diagnostic, therapeutic, or other types of interventions.

Commercially confidential information (CCI)

Confidential intellectual property, “know-how” and trade secrets (including e.g. formulas, programs, process or information contained or embodied in a product, unpublished aspects of trade marks, patents etc.) and commercial confidences (e.g. structures and development plans of a company).

Dose escalation

Increasing the amount of study drug given to the participants.

Double blind

None of the participants, trial doctors, or staff know what treatment each participant received.


The power of a drug to produce the intended result.

European Medicines Agency (EMA)

European Union agency for the evaluation of medicinal products.

Food and Drug Administration (FDA)

United States agency for the evaluation of medicinal products.


The treatment type given to the participant. This can include medicines, medical devices or vaccines.

Investigational New Drug (IND)

A biological product or drug that has not yet been approved for general use by the FDA. This product/drug is under investigation in a clinical trial.


A researcher involved in a clinical trial or observational study.


A large-scale clinical trial that is conducted at more than one medical centre.

Observational study

A clinical study in which participants identified as belonging to study groups are assessed for biomedical or health outcomes. Participants may receive diagnostic, therapeutic, or other types of interventions, but the investigator does not assign participants to specific interventions (as in an Interventional study).

Open label

The participants, trial doctors and staff, and the sponsor know what drugs the participants are getting.

Personal Protected Data (PPD)

Protected data related to a living individual who can be identified from that data.


A placebo looks like the trial drug but has no real medicine in it.

Phase 1

Studies that emphasize safety and are usually conducted with healthy volunteers. The goal is to find out what the drug’s most frequent and serious adverse events are and, often, how the drug is metabolized and excreted.

Phase 2

Studies that gather preliminary data on effectiveness (whether the drug works in people who have a certain disease or condition). For example, participants receiving the drug may be compared to similar participants receiving a different treatment, usually an inactive substance, called a placebo, or a different drug. Safety continues to be evaluated, and short-term adverse events are studied.

Phase 3

Studies that gather more information about safety and effectiveness by studying different populations and different dosages and by using the drug in combination with other drugs.

Policy 0070

European Medicines Agency policy on publication of clinical data for medicinal products for human use.

Principle investigator (PI)

The lead researcher who is responsible for the entire clinical study.

Randomized allocation

Participants are assigned to an intervention by chance alone.


The process of masking / obscuring content within a document i.e. text, images. This is done for Commercially confidential information and Personal Protected Data in accordance with EMA policy 0070.

Serious adverse event (SAE)

An adverse event is called “serious” when it is life-threatening, causes lasting problems, or the participant needs to be admitted to a hospital.


The lead company/organization of a clinical study.

Study phase

The stage of a clinical trial. There are 3 main phases (phase 1, phase 2 and phase 3).