Clinical Trials 101

Build your Knowledge. Know the language.

Knowing the terminology can help you make an informed decision.

Our biggest fears often come from the unknown. We’ve put together a list of common terms to help guide you through the sometimes-intimidating process of determining whether to participate in a clinical trial. We’ve often found that having a basic understanding of these terms can lighten the already heavy load most people bring with them when making important medical decisions.

The Language of Clinical Studies1

Active Comparator

A medication that is considered to be effective, that is used in research to measure the study medication against.

Clinical Trial Coordinator

This person is a member of the research team who makes sure that the clinical trials are run under the current standards of GCP (good clinical practice).

Clinical Trial

A research study in which people are enlisted to help us test out new potential therapies and treatments.

Double-Blind Studies

Both participants and researchers do not know if the investigational drug or placebo is being used. This is so they can all describe what’s happening without bias.

Head-to-Head Study

Research that directly compares the study medication to another medication considered to be effective.

Healthy Volunteer

Someone who doesn’t have the disease being studied who joins a clinical study to test a new treatment option.


A class of drugs that suppress or reduce the strength of the body’s immune system.

Inclusion/Exclusion Criteria

The factors used to determine if someone is eligible to participate (inclusion) or not eligible (exclusion) to participate in a clinical trial.

Informed Consent

Allows you to make an informed decision as to whether or not you want to take part in this research study. This document describes the purpose of the study, your rights and obligations, the procedures needed by the study, and the possible benefits and risks of participating in the study.

Open-Label Extension

After the controlled study, in which some participants receive the study medication and others receive a different medication or placebo, participants may qualify to take the study medication, regardless of which medication they received earlier in the study. It is called “open label” because both the participant and the research team know that the participant is taking the study medication.

Oral Corticosteroid

A medication used to provide relief for inflamed areas of the body. It lessens swelling, redness, itching, and allergic reactions.
Participant Volunteer

An individual who participates in a clinical trial and receives the study treatment, a comparator treatment, or a placebo.

Phases of Clinical Trials

Clinical trials are done in segments known as phases.

  • Phase I trials—A study medication that’s being tested for the first time in a small group of people, often healthy volunteers. There are instances when participants with the existing condition are being studied as well. The main goal is to look at the side effects and safety of the treatment.
  • Phase II trials—The study medication is administered to a larger group of people to learn about its safety, test the dose, and see if it works well enough to move into a phase III trial.
  • Phase III trials—The study medication is administered to large groups of people to test whether the benefits of the study medication are greater than the risks.

A substance that looks like the study treatment (a pill, liquid, or injectable) but does not contain any medication. The clinical results from trial participants taking placebo are compared to the results from participants taking the study medication to see if the study medication works.


A document that describes the objectives, design and organization of a clinical trial.

Principal Investigator

A physician that leads the research team. This physician is responsible for running the clinical trial at the study site, making sure the study is managed ethically and follows the protocol.


When you are “randomized” into the study, this means that you are put into a group by chance (like tossing a coin). Neither you nor your study doctor may choose the group you will be in.

Study Nurse

This member of the research team is responsible for administering the procedures and monitoring the safety of each participant during the trial, in partnership with the principal investigator. These duties include, but are not limited to: maintaining a safe environment, keeping accurate records, and making sure participants and the research team members are communicating with one another.

Subcutaneous Injection

A subcutaneous injection is a shallow, relatively painless injection similar to those used for flu shots or other vaccines. “Subcutaneous” means the needle penetrates just beneath the skin.

An agent that targets an inflammation-causing substance called Tumor Necrosis Factor (TNF). TNF is a protein produced by the immune system that causes inflammation in the body. In healthy individuals, excess TNF in the blood is blocked naturally, but in those who have rheumatic conditions, higher levels of TNF in the blood lead to more inflammation and persistent symptoms.

Learn about the Etro Studies, a clinical trial testing an investigational treatment for Crohn’s and Ulcerative Colitis, and find out if the Etro Studies could be right for you.


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