Active, not recruiting

The clinical trial is happening, but researchers are not looking for more participants at this time.

Adverse event

A medical problem that happens or worsens during a clinical trial or within a certain time period after the trial is over. An adverse event may or may not be caused by the investigational treatment a person took.

Clinical trial (or research study)

A clinical trial is a research study designed to learn how our bodies respond to investigational medicines or other investigational treatments. During the clinical trial, participants are assigned to get a treatment or sometimes, no treatment. The purpose of a trial is usually to find ways to prevent, diagnose or treat a disease or other health condition.

Clinical trial phases

Before health authority approval, any treatment (vaccine, medicine, medical device or procedure) must go through 3 phases of clinical trials. Sometimes phase 4 trials are conducted after approval. Each phase tests the treatment’s safety, how well it works, amount (dose), and side effects.


A disease, disorder, syndrome, illness or injury that researchers are studying.

Controlled trial

A type of clinical trial that compares one treatment to another treatment. Often, a new investigational treatment is compared to a standard or usual treatment (called the control). The control may be a group of participants in the same trial or a group of participants from an earlier trial or study.

Eligibility criteria

A clinical trial’s requirements for people who want to join. These include inclusion criteria (factors that allow a person to join a trial) and exclusion criteria (factors that prevent a person from joining a trial). For example, a trial might only accept participants who are above or below certain ages.


The number of participants in a clinical trial. The “estimated enrolment” is the number of participants that the researchers need for the trial.

Exclusion criteria

The factors (or reasons) that prevent a person from joining a clinical trial.

Expanded access

A process regulated by the regulatory agencies that allows pharmaceutical companies to provide a new investigational treatment (before it’s registered) to patients with serious diseases or conditions who cannot take part in a clinical trial.

Inclusion criteria

The factors (or reasons) that allow a person to join a clinical trial.

Informed consent

Informed consent is the process in which researchers talk with people who are thinking about enrolling, or have enrolled, in a clinical trial. You will need to read an informed consent form (ICF) that describes the possible benefits and risks. It tells you that taking part in the trial is voluntary, and that you may leave the trial at any time.

The goal of the informed consent process is to protect the participants who enrol in clinical trials. The informed consent process starts when a possible participant first asks for information about a trial and continues until the trial ends.

Informed consent form (ICF)

The document used in the informed consent process.

Investigational medication

A medication or biological product that is used in a clinical trial but has not been registered by health authorities (the medication is either not available for a doctor to prescribe or is available but not registered by the health authority for the use being studied).

Human Research Ethics Committee (HREC)

A Human Research Ethics Committee (HREC) is a committee of doctors, statisticians, community advocates and others that helps ensure that a clinical trial is conducted in an ethical manner and that the rights of study participants are protected. All institutions that conduct or support biomedical research involving people must, by regulation, have an HREC that initially approves and periodically reviews the research.


A look-alike substance that does not contain an active medication or treatment. A placebo is made to look, taste and be given like the actual medication being studied.


The written description of a clinical trial. It includes the trial’s goals, design and methods. It may also include data and science-related background information.


The organisation or person who starts the trial, pays for it, and has authority and control over it.


A treatment that helps provide protection from certain infections, usually given as a shot.

Still have questions?

Our FAQ section has answers to commonly asked questions and a glossary of words to know.


Frequently asked questions