Glossary of Clinical Research - E

E

• Efficacy

• The maximum ability of a drug or treatment to produce a result regardless of dosage. A drug passes efficacy trials if it is effective at the dose tested and against the illness for which it is prescribed. In the procedure mandated by the FDA, Phase II clinical trials gauge efficacy, and Phase III trials confirm it (NLM)
• Effectiveness. In medicine, the ability of an intervention (for example, a drug or surgery) to produce the desired beneficial effect. (NCI)

• Eligibility criteria

• In clinical trials, requirements that must be met for an individual to be included in a study. These requirements help make sure that patients in a trial are similar to each other in terms of specific factors such as age, general health, and previous treatment. When all participants meet the same eligibility criteria, it gives researchers greater confidence that results of the study are caused by the intervention being tested and not by other factors. (NCI)
• Summary criteria for participant selection; includes Inclusion and Exclusion criteria. (NLM)

• Empirical

Based on experimental data, not on a theory. (NLM)

• Endpoint

• In clinical trials, an event or outcome that can be measured objectively to determine whether the intervention being studied is beneficial. The endpoints of a clinical trial are usually included in the study objectives. Some examples of endpoints are survival, improvements in quality of life, relief of symptoms, and disappearance of the tumor. (NCI)
• Overall outcome that the protocol is designed to evaluate. Common endpoints are severe toxicity, disease progression, or death. (NLM)

• Enrolling

The act of signing up participants into a study. Generally this process involves evaluating a participant with respect to the eligibility criteria of the study and going through the informed consent process. (NLM)

• Epidemiology

• The branch of medical science that deals with the study of incidence and distribution and control of a disease in a population. (NLM)
• The study of the patterns, causes, and control of disease in groups of people. (NCI)

• Equivalence trial

A trial with the primary objective of showing that the response to two or more treatments differs by an amount which is clinically unimportant. This is usually demonstrated by showing that the true treatment difference is likely to lie between a lower and an upper equivalence margin of clinically acceptable differences. (ICH E9)

• Essential Documents

Documents that individually and collectively permit evaluation of the conduct of a study and the quality of the data produced. (ICH E6)

• Evaluable disease

Disease that cannot be measured directly by the size of the tumor but can be evaluated by other methods specific to a particular clinical trial. (NCI)

• Evaluable patients

Patients whose response to a treatment can be measured because enough information has been collected. (NCI)

• Expanded access

Refers to any of the FDA procedures, such as compassionate use, parallel track, and treatment IND that distribute experimental drugs to participants who are failing on currently available treatments for their condition and also are unable to participate in ongoing clinical trials. (NLM)

• Expanded access trial

A way to provide an investigational therapy to a patient who is not eligible to receive that therapy in a clinical trial, but who has a serious or life-threatening illness for which other treatments are not available. Expanded access allows a patient to receive promising but not yet fully studied or approved therapies when no other treatment option exists. Also called compassionate use trial. (NCI)

• Experimental

In clinical trials, refers to a drug (including a new drug, dose, combination, or route of administration) or procedure that has undergone basic laboratory testing and received approval from the U.S. Food and Drug Administration (FDA) to be tested in human subjects. A drug or procedure may be approved by the FDA for use in one disease or condition, but be considered experimental in other diseases or conditions. Also called investigational. (NCI)

• Experimental drug

• A drug that is not FDA licensed for use in humans, or as a treatment for a particular condition (NLM)
• A substance that has been tested in a laboratory and has gotten approval from the U.S. Food and Drug Administration (FDA) to be tested in people. A drug may be approved by the FDA for use in one disease or condition but be considered experimental or investigational in other diseases or conditions. Also called investigational drug. (NCI)