Clinical Trials Glossary

Administration: The act of giving medication or treatment. For example, DX-88 for HAE is currently administered intravenously and subcutaneously.

Adult: For the purposes of clinical trials, people age 18 and over (17 in some states) are considered adults capable of deciding if a clinical trial is right for them. If a person is under age 18, a parent or guardian must make this decision. (See informed consent.)

Adverse Event (AE): For safety's sake, any unwanted, negative medical occurrence during the time a patient participates in a clinical trial is called an adverse event. All adverse events are documented, whether or not they seem related to the experimental drug. The study physician then decides if the AE is related to the experimental drug and reports this information as well.

Arm: The treatment or intervention groups in a clinical trial are referred to as trial or study arms.

Biologics License Application (BLA): A BLA is a document submitted to the FDA by a manufacturer seeking to introduce a biologic product into interstate commerce. Genes, organic antigens, and blood products are examples of products that would require a BLA.

Blinded: In a blinded trial, some or all parties do not know which patients received the experimental treatment. By removing the opportunity for bias, successful blinding gives researchers and the FDA a more objective look at a drug's efficacy and safety. Trials may be single blind or double blind, but these terms are often general and it is more informative to specify if the researchers, patients, outcome assessors, and/or statisticians are blinded.

Compassionate Use: With the sponsor's and FDA's consent, an experimental drug may be administered to a sick patient lacking other treatment options through a compassionate use protocol.

Controlled: A study comparing an experimental treatment with no treatment, a placebo, or another established drug is said to be controlled.

Dose-ascending: A dose-ascending trial investigates progressively higher doses of the experimental drug in order to determine the optimum dose. Depending upon the trial design, the same patient may be given sequentially larger doses, or a subsequent group of patients may receive a higher dose than the last group did.

Dose effect: If a drug becomes more or less effective at increasingly higher doses, there is said to be a dose effect.

Dose-ranging: A dose-ranging trial compares different doses of experimental drug in order to determine the optimum dose. (See dose-ascending)

Dose-response: When a drug's efficacy increases in response to higher doses, this is said to constitute a dose-response effect.

Double-blind: In a typical double-blind trial, neither the researchers nor the patients know which treatment is being administered. However, this term is occasionally used to refer to other groups (see blinded).

Effectiveness: Effectiveness describes how well an approved, marketed drug works during regular use.

Efficacy: Efficacy is used to describe how well a drug works under optimum conditions, such as during a closely monitored clinical trial.

EMEA: The European Medicines Agency governs the approval of drugs in the European Union, much like the FDA does in the U.S.

Exclusion criteria: The conditions or circumstances that disqualify a patient from participating in a clinical trial are called exclusion criteria. These are set for patients' safety or to make the results of the trial clearer. In cases in which a patient is very sick and has no other treatment options, the patient may be able to receive the experimental drug outside of the study (see compassionate use).

Fast Track: If the FDA determines that a drug shows promise in meeting a severe, unmet medical need, it may grant the drug's sponsor a fast track designation for the development of that drug. For most drugs, the FDA has 12 months to review marketing approval documents; the FDA must review similar materials for fast-tracked drugs within 6 months.

FDA: The U.S. Food and Drug Administration is a collection of government employees responsible for ensuring that foods, drugs, and cosmetics sold in the U.S. are safe for use, and, in the case of drugs, effective as well.

Inclusion criteria: The set of requirements (e.g., age, health status) that a patient must meet to be included in a clinical trial are called inclusion criteria.

Indication: The disease or condition a drug is designed to treat is referred to as its indication. A single drug may have multiple indications.

Informed Consent: Before enrolling in a clinical trial, patients or healthy subjects must be informed, in language that they can understand, of the possible risks and benefits associated with their participation. People who decide to participate must first sign an informed consent form signifying their knowledge and agreement to participate.

Institutional Review Board (IRB): An IRB is composed of an independent, local group of researchers and community advocates who must review and approve each clinical trial protocol and associated consent materials before patients may be treated at their site.

Investigational New Drug Application (IND): An IND is a comprehensive document detailing an experimental drug's known properties. This document must be approved by the FDA before US clinical trials may begin.

Investigator: A study physician who oversees the running of a clinical trial at a particular site is referred to as an investigator. If multiple physicians become involved at a single site, the first physician to participate is typically considered the principal investigator and the others, sub-investigators.

New Drug Application (NDA): An NDA is an informational petition to the FDA, containing records of all clinical and preclinical investigations and requesting permission to market the drug in the US.

Objective: A predetermined question a clinical trial sets out to answer is called an objective. Researchers often want to understand many things about an experimental drug, so clinical trials frequently have multiple objectives.

Off-label: When an approved drug is used to treat conditions other than those approved by the FDA, this is said to be an off-label use.

Open-label: An open-label study uses no blinds or placebos. In such a study, both researchers and participants know what treatment is being given.

Orphan Drug: An orphan drug is a medication that has received a special status from the FDA because it is designed to treat a very rare condition. The FDA established the orphan drug designation to reduce the cost of drug development for drugs needed by small numbers of patients.

Phage: Phage is short for bacteriophage, a microscopic virus that infects only bacteria. If genes are the blueprints for proteins; phage are like general contractors. Dyax uses phage to insert genes in bacteria, the bacteria make the protein according to plan, and the phage display the protein on the bacteria's surface.

Pharmacokinetics: The study of how, and how quickly a drug distributes in the body and is eliminated is called pharmacokinetics.

Phase I: Phase I trials are small trials conducted in healthy volunteers or sometimes in patients. These trials are primarily concerned with determining a drug's safety and possible optimum dose.

Phase II: Phase II trials typically include more patients than Phase I trials and may offer more information about a drug's optimum dose. These trials begin to focus on a drug's efficacy and may be controlled.

Phase III: Phase III trials are often quite large and compare the safety and efficacy of an experimental drug with that of current therapies or a placebo.

Phase IV: Phase IV trials are those undertaken after a drug has earned marketing approval, typically to gather additional information or pursue an additional indication.

Placebo: An inactive substance designed to mimic the experimental treatment is called a placebo.

Preclinical: Preclinical experiments are those conducted in laboratories without human subjects.

Protocol: The written plan describing a clinical trial is called a protocol. Protocols must first be approved by both the FDA and a local authority (see IRB) before patients may participate.

Recombinant: Genes work as directions for making proteins. When scientists combine genetic material from two or more different sources, the resulting gene is said to be recombinant. If that gene is expressed (used to make a protein), the resulting protein is also described as recombinant.

Repeat-dose: A repeat-dose trial studies the effects of more than one dose of experimental drug. Such studies are typically conducted only after safety data have been gathered on single doses of the drug.

Safety or Safety Profile: A drug's safety profile is a summary of all side effects that might have been related to its administration relative to the number of times the drug has been administered. A drug that has been administered many times and produced only mild or no side effects is said to have an excellent safety profile.

Single-blind: A study in which only researchers or only participants know which treatment is being given is referred to as a single-blind study.

Single-dose: A trial in which only one dose of experimental drug or placebo is given is referred to as a single-dose study.

Sponsor: The company or institute funding and overseeing a drug during the clinical trials process is considered the drug's sponsor.

Statistician: a statistician is someone trained in mathematical methods for determining whether or not an event is due to chance. Both a drug's sponsor and the FDA employ statisticians to analyze data from clinical trials.