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Glossary of Clinical Research Terms






ABSORB/ABSORPTION: The passage of substances into or across tissues, such as the passage of food and water from the intestines into the bloodstream. Because of a lack of digestive enzymes, some foods eaten by people with CF may not be well absorbed and used by the body (see DIGESTIVE SYSTEM, ENZYMES, PANCREAS, INTESTINE and MALABSORPTION).

ADVERSE REACTION: Unwanted side effect resulting from a drug or mixture of drugs. It may appear quickly or over time (see SIDE EFFECTS).

AEROSOLIZED: A liquid substance released as a spray.

AIRWAYS: Tubes that bring outside air into the lungs. The lungs have many airways of varied sizes. The largest is the trachea between the throat and the lungs. It branches into smaller airways in the lungs called bronchi. These divide into still smaller branches called bronchioles. These turn into alveoli, the very smallest airways.

ALVEOLI: A tiny, thin-walled, capillary rich sac in the lungs where exchange of oxygen and carbon dioxide takes place. Singular: Alveolus.

AMINOGLYCOSIDES: A group of antibiotics used to treat bacterial infections. Tobramycin and gentamicin are examples of aminoglycosides used in CF treatment (see ANTIBIOTIC and BACTERIA).

ANTIBIOTIC: A drug that kills bacteria or slows bacterial growth. Antibiotics are often used to treat lung infections (see AMINOGLYCOSIDES, BACTERIA and CEPHALOSPORINS).

ANTI-INFLAMMATORY AGENT: Medication to reduce inflammation or irritation of body tissue. Ibuprofen is an example of an anti-inflammatory agent used in CF treatment.

ANTIBODY: molecule in the body that combines with a foreign bacteria or virus to stop its activity or signal other molecules in the body to become active in fighting the foreign germ.

ANTIMICROBIAL: Can stop the growth of disease-causing germs.

APPROVED DRUG: In the United States, only drugs approved by the Food and Drug Administration (FDA) can be sold. The approval process involves several steps, including pre-clinical laboratory and animal studies, clinical trials for safety and effectiveness, filing a New Drug Application by the drug manufacturer, FDA review and approval of the application (see FOOD AND DRUG ADMINISTRATION).

ARM: Any of the treatment groups in a randomized trial. Most randomized trials have two arms, but some have three or more (see RANDOMIZED TRIAL).

ASSAY: A way to measure how many parts of a certain ingredient are in a larger system, object or mixture.

AUTOSOMAL RECESSIVE: A genetic trait or disorder that appears only when a person inherits a pair of chromosomes, each of which has the gene for the trait. One chromosome of the pair comes from the father and the other from the mother. Autosomal recessive disorders occur only if each parent is either a carrier of the trait or has the trait. CF is an autosomal recessive disease (see CARRIER and GENE).

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BACTERIA: Tiny one-celled creatures that are often the cause of infections. People with CF are prone to bacterial lung infections (often caused by the bacteria Staphylococcus aureus and Pseudomonas aeruginosa). Some bacteria normally found in the body are helpful. For example, Escherichia coli live in the intestines and help with digestion (see ANTIBIOTIC, INTESTINE, PSEUDOMONAS AERUGINOSA and STAPHYLOCOCCUS AUREUS).

BALANCED STUDY: When a particular type of participant (for instance, females, people with certain lung function levels, African Americans, etc.) is equally represented in each study group.

BIAS: A point of view that impairs fair judgment. In clinical trials, bias is controlled by blinding and randomization (see BLIND TRIAL and RANDOMIZATION).

BIOFILM: A substance that sticks to wet surfaces. Biofilms can form on solid or liquid surfaces as well as on soft tissue in living organisms. They are usually difficult to dissolve. In CF, a biofilm, or protective coating, is formed by Pseudomonas aeruginosa bacteria and prevents drugs from killing the bacteria.

BIOMARKERS: A biochemical or a substance in the body that can be used to measure disease activity or effects of treatment.

BILE: A bitter fluid produced by the liver and stored in the gallbladder. Bile is discharged into the small intestine when needed to aid in the digestion of fats.

BILIARY FIBROSIS: A disease of the gallbladder, bile ducts, and bile characterized by the replacement of normal tissue with fibrous tissue and loss of functional cells.

BLIND TRIAL: A clinical trial in which participants are unaware whether they are taking the experimental drug, placebo or standard treatment. (see SINGLE BLIND TRIAL and DOUBLE BLIND TRIAL).

BMI (Body Mass Index): A measurement comparing fat to muscle in the human body. Weight in kilograms is divided by height in meters to figure out the degree of nutritional health, such as determining malnutrition or obesity.

BROAD SPECTRUM: An antibiotic that is effective against a wide range of organisms.

BRONCHO-ALVEOLAR FLUID: Fluid found in the bronchiole and alveoli part of the lungs.

BRONCHO-ALVEOLAR LAVAGE: A diagnostic test where fluid is taken from the bronchioles and alveoli part of the lungs.

BRONCHOSCOPY: A procedure using a small tube (bronchoscope) to look down the throat and inside the lungs.

BURKHOLDERIA CEPACIA COMPLEX: Bacteria that can live in the lungs of people with CF and cause infection. This bacterium is resistant to antibiotics and easily spread between people with CF, and can cause life-threatening lung infections.

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CADAVERIC: Having to do with a dead body (a cadaver).

CARRIER: A person having a single gene for a genetic trait or disorder like CF. Carriers show no signs of the disease. In CF, each parent of a child with CF either has CF or is a CF carrier (see GENE and HEREDITARY).

CELL: The basic unit of living organisms.

CEPHALOSPORINS: A group of antibiotics used to treat bacterial infections (see ANTIBIOTIC and BACTERIA).


CHROMOSOME: The thread-like material that carriers genes, the units of heredity. Chromosomes are in the nucleus of every living cell. Every person should have 23 pairs of chromosomes in each cell.

CHRONIC: A disease or condition that lasts and is continuous. CF is a chronic disease.

CIRRHOSIS:  A chronic disease of the liver characterized by the replacement of normal tissue with fibrous tissue and the loss of functional liver cells.

CLINICAL: Related to the study and treatment of people in a medical setting or clinic.

CLINICAL ASSESSMENT: An evaluation of the symptoms and progression of a disease.

CLINICAL INVESTIGATOR: A medical researcher, most often a medical doctor, responsible for carrying out a clinical research protocol (see PROTOCOL and PRINCIPAL INVESTIGATOR).

CLINICAL STUDY: A type of research—also called observational research—in which participants are observed. While these studies do not use drugs or treatments, they are very important for developing new ideas about how diseases or progression of disease could be prevented or treated.

CLINICAL TRIAL: A type of research—also called interventional research—that follows certain government guidelines for testing the effect of drugs on people. Researchers observe how the drug affects the body under highly controlled conditions and whether the treatment is helpful.

CLINICALLY STABLE: When symptoms are not changing or progressing and, for the time being, are not expected to.

COMPASSIONATE USE: When experimental drugs are provided to people before final FDA approval. Typically used only with individuals who may receive benefit but have no other treatment options and cannot enroll in a clinical trial.

COMPLEX DOSAGE REQUIREMENTS: When clinical trial participants are required to take an experimental drug or treatment several times a day or to take a combination of drugs and treatments.

COMPUTED TOMOGRAPHY (CT scan): A three-dimensional image or picture of the body showing three measurements, such as height, width and depth. Created by a computer from a series of cross-sectional pictures.

CONDENSATE: Something that has turned into liquid, such as a liquid reduced from a gas or vapor, like water from steam.

CONFIDENTIALITY: The FDA and medical ethics require that the identities and medical information of all clinical trial participants be kept confidential. When a person joins a clinical trial, they must agree to share their medical records with researchers. The Principal Investigator must guarantee these records remain confidential (see FDA and PRINCIPAL INVESTIGATOR).

CONTRAINDICATED: Used to describe when certain medicines or treatments should not be used.

CONTROL GROUP: In many clinical trials, one group of patients receives the experimental drug or treatment, while the control group receives either a standard treatment or placebo (see PLACEBO and STANDARD TREATMENT).

CONVENTIONAL: Following what is traditional or customary. Not new or experimental.

CULTURE: Sputum or throat swab is put on a medium for germs to grow in the laboratory, so the germ can be identified.

CYSTIC FIBROSIS CONDUCTANCE TRANSMEMBRANE REGULATOR (CFTR): A protein in the cell that makes the channel where chloride moves in and out. The defect in the channel causes CF.

CYSTIC FIBROSIS-RELATED DIABETES (CFRD): The body’s inability to move sugar from the blood into the cells for energy. A special form of diabetes found in people with CF.

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DATA SAFETY MONITORING BOARD (DSMB): An independent committee of clinical research experts and community representatives that reviews ongoing information from a clinical trial. The committee’s job is to watch for safety issues and ensure participants are not exposed to unnecessary risk. The DSMB can recommend that a trial be stopped.

DEFICIENCY: A lack of something necessary to good health. An insufficiency. Example: a Vitamin D deficiency in people with CF.

DEHYDRATED: Remove moisture.

DETECT: To discover the existence, presence, or fact of. To uncover something that has been hidden or is not as it should be.

DETERIORATION: The process of becoming worse. Example: when someone’s health deteriorates.

DIAGNOSE: To find the cause of health problems.

DIGESTION: The process of breaking down the food we eat and absorbing its nutrients into the body for energy (see ABSORPTION).

DIGESTIVE SYSTEM: The organs that take in, digest and get rid of food. Includes the mouth, salivary glands, pharynx (throat), esophagus, stomach, intestines, liver, pancreas, colon, rectum and anus. In CF, thick mucus blocks some passages in the digestive system, like that between the pancreas and intestines.

DOSAGE: The prescribed amount of a drug that must be taken to get the benefit or intended result.

DOUBLE BLIND TRIAL: A clinical trial in which neither the participants nor the staff knows which patients are receiving the experimental drug and which are receiving a placebo or standard therapy. Double blind trials are thought to be more objective because expectations of the physician and the participants don’t affect the outcomes (see BLIND TRIAL, SINGLE BLIND TRIAL and PLACEBO).

DRUG-DRUG INTERACTION: Changes in the effect of a drug when taken with another drug. The effect may be an increase or a decrease in the action of either drug, or it may be an adverse effect normally not associated with either drug (see ADVERSE REACTION).


DUCT: A tube or passageway for secretions. Ducts are found in organs, such as the pancreas, organ systems and exocrine glands. In CF, thick mucus can block these ducts (see SECRETION).

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EFFICACY: The ability of a drug to produce a desired effect. A drug will pass efficacy trials if it is effective at the dose tested against the illness for which it was prescribed.

ELIGIBILITY CRITERIA: Reasons for selection of participants to be excluded from a clinical trial (see INCLUSION/EXCLUSION CRITERIA).

ENERGY INTAKE: Energy helps cells perform all of their functions, including building proteins and other substances the body may require. Energy intake is based on food that is eaten.

ENROLL: Joining a clinical trial, after meeting all necessary criteria and signing the Informed Consent Form (see INCLUSION/EXCLUSION CRITERIA and INFORMED CONSENT DOCUMENT).

ENZYMES: Proteins that help make and increase certain chemical processes in the body, like the breaking down of foods in digestion. Because people with CF have mucus that often blocks the passageways (or ducts) through which digestive enzymes from the pancreas flow, they may need enzyme replacements to digest food (see ABSORPTION, DIGESTIVE SYSTEM, MUCUS and PANCREAS).

ESOPHAGUS: The tube that leads from the throat (pharynx) to the stomach.

EXACERBATION: Signs and symptoms that show a need for treatment.

EXCLUSION/INCLUSION CRITERIA: Standards used to decide whether a person may or may not enroll in a clinical trial. Criteria are based on such factors as age, gender, disease, previous treatment history, and other medical conditions. These criteria are not used to keep people out of clinical trials, but rather to identify the right participants and keep them safe in a trial.

EXHALATION: Breath out air.

EXPANDED ACCESS: Refers to any of the FDA procedures for distributing experimental drugs to patients who are no longer benefiting from currently available treatments and unable to participate in ongoing clinical trials (see COMPASSIONATE USE, PARALLEL TRACK and TREATMENT IND).

EXPERIMENTAL DRUG: A drug not licensed by the FDA for use in humans (see OFF-LABEL USE).

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FAILURE TO THRIVE: Not gaining weight or growing at a normal rate.

FOOD AND DRUG ADMINISTRATION (FDA): The agency of the U.S. Department of Health and Human Services (DHHS) responsible for monitoring the safety and effectiveness of all drugs, biologics, vaccines and medical devices, including those used in the diagnosis, treatment and prevention of CF and other diseases (see

FORMULATION: A prescribed recipe for making a drug.

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GASTROESOPHAGEAL REFLUX DISEASE (GERD): a condition in which food or liquid travels backwards from the stomach to the esophagus (the tube from the mouth to the stomach). This action can irritate the esophagus, causing heartburn and other symptoms.

GENE: The main unit of heredity. Each chromosome carries hundreds of genes. Genes decide body traits like eye and hair color, height, facial features and many health problems. CF is caused by an alteration of a gene. A child inherits CF when two CF genes are received, one from each parent (see AUTOSOMAL RECESSIVE, CARRIER and HEREDITARY).

GENETIC: Hereditary or inherited. Material that is passed on from parents to children (see GENE).

GLAND: A group of cells that make substances so that other parts of the body can work. The pancreas is a gland that makes enzymes so food can be broken down and absorbed by the body.

GLUCOSE: A sugar.

GOOD CLINICAL PRACTICE (GCP): The standard for clinical trial design, conduct, performance, monitoring, auditing, recording, analyzing and reporting. GCP ensures that reported results will be credible and accurate, and that the rights, integrity and confidentiality of patients are protected.

GRAM NEGATIVE: Bacteria that does not retain the violet dye stained by Gram’s stain method (method classifies bacteria as positive or negative).

GRAM POSITIVE: Bacteria that retain the violet dye when stained by Gram’s stain method (method classifies bacteria as positive or negative).

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HEREDITARY: Traits or conditions, like eye color or CF, that are genetically passed from parents to their children (see GENE and GENETIC).

HETEROZYGOUS: Having different pairs of genes for any hereditary characteristic

HIGH-RESOLUTION COMPUTER TOMOGRAPHY (CT scan): A three-dimensional image or picture of the body. Created by a computer from a series of cross-sectional pictures with edge-defining qualities to sharpen the image, sometimes with a closer view of a smaller area. A close-up CT scan. Used often to create images of a person’s lungs (see COMPUTED TOMOGRAPHY).

HOMOZYGOUS: Having the same pairs of genes for any hereditary characteristic.

HORMONE: Secretion from glands. Hormones regulate body functions like growth and heart rate.

HYDRATING: Add moisture.

HYPERGLYCEMIA: Higher than normal blood glucose or blood sugar in the bloodstream.

HYPOTHESIS: Theory or assumption used as a guide in clinical research.


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IMMUNE: Resistant to infection by a specific germ.

IMPAIRED GLUCOSE TOLERANCE: A fasting blood sugar of 100 to 125 mg/dL and /or a blood sugar of 140 to 199 mg/dL 2 hours after an oral glucose load during an oral glucose tolerance test (OGTT).

INACTIVE (Inert): Having no effect.

INCLUSION/EXCLUSION CRITERIA: Standards used to decide whether a person may or may not enroll in a clinical trial. Criteria are based on such factors as age, gender, disease, previous treatment history, and other medical conditions. These criteria are not used to keep people out of clinical trials, but rather to identify the right participants and keep them safe in a trial.

INDICATION: Something that points to or suggests the proper treatment of a disease, as required by the cause or symptoms. Like a tip-off, or clue, that certain action is required.

INDUCTANCE PLETHYSMOGRAPHY: A machine to measure lung volume and lung health in people ages 6 years of age and older. Sometimes called a “body box.”

INFLAMMATION: The swelling of body tissues due to irritation or injury. Inflammation occurs with an infection.

INFORMED CONSENT: The process of learning about a clinical study or trial before deciding whether to join. Doctors and nurses involved in the trial fully explain the study and answer any questions. The goal is to have people participate who are informed about the study or trial.

INFORMED CONSENT DOCUMENT: A document that describes the rights of clinical research participants and details about the study or trial. It includes the study’s purpose, length, required procedures, and staff contact information. It also explains any risks and potential benefits. The patient should ask the study staff any questions before signing.

INHALE: To breathe in.

INHERITED: Traits or conditions, like eye color or CF, that are genetically passed from parents to their children (see GENE and GENETIC).

IN-PATIENT (IN-PATIENT STUDY/TRIAL): Hospitalized patient. Study or trial that requires time in a hospital.

INSTITUTIONAL REVIEW BOARD (IRB): Committee of research and disease experts, and community advocates working to ensure that a clinical trial is fair and ethical, and that the rights of all participants are protected. All clinical trials in the United States must be approved by an IRB before they can begin. This group approves the initial research and reviews the research as it progresses to help protect the rights and safety of participants. The IRB also must approve all materials prepared for participants, including the informed consent document, promotional posters, flyers, brochures, Web sites, and other items.

INTERVENTIONS: Approach to treating a disease or condition. Intervention is a word frequently used to describe a treatment or therapy.

INTESTINE: Tube in the digestive system that connects the stomach to the anus. The long, narrow, upper part is the small intestine. The short, wide, lower part is the large intestine. Also called the bowel.

INTRAMUSCULAR: In the muscle. Example: a “shot” or intramuscular injection.

INTRAVENOUS (IV): Putting a medicine right into a blood vessel, usually a vein, using a thin needle and a tube.

INVESTIGATIONAL NEW DRUG (IND): An experimental drug that is approved by the FDA for use in clinical trials.

INVESTIGATIONAL TREATMENT: An unapproved treatment, or a treatment used for a new purpose in clinical research. This is usually a drug.

IN VITRO: Latin for “in glass.” Usually refers to research in a laboratory, outside the body.

IN VIVO: Latin for “in living (body).” Usually refers to research done in living animals and humans.

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LIVING DONOR: A living person who donates a body part for transplantation into another person. Many different types of organs can come from living donors, like a kidney, or a lobe of a lung or liver.

LIVING SYSTEMS: Human, animal, or cell environments used for experimental purposes in clinical trials (see IN VITRO and IN VIVO).

LOBAR: A well-defined part of an organ or gland. The lungs have several distinct lobes.

LUNG CLEARANCE INDEX (LCI): The result (a number) obtained from a multiple breath washout test. A higher number reflects more airway obstruction and a low number a healthier lung. A patient with more obstruction will take longer to clear the gas mixture from their lung and the result is a higher number or index (see MULTIPLE BREATH WASHOUT).

LUPUS: Any of several diseases, which first affect the skin and joints, but often involve other parts of the body.

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MACROLIDES: A group of antibiotics used to treat lung infections, including azithromycin and erythromycin.

MALABSORPTION: Poor uptake of nutrients from food for use by the body. In CF, mucus may plug ducts of digestive organs and block the secretion of enzymes and hormones. This makes many nutrients unavailable for use in body maintenance and growth (see ABSORPTION, DIGESTION, DIGESTIVE SYSTEM, DUCT, ENZYME, FAILURE TO THRIVE, HORMONE, MUCUS, ORGAN, PANCREAS and SECRETION).

MARKERS: A substance in the body that, when present in large or abnormal amounts, suggests the presence of disease. Also called a biomarker.

MICROBIOLOGY: The branch of biology that deals with microorganisms and their effects on other living organisms. The study of microscopic forms of life (such as bacteria, viruses, and fungi).

MICROORGANISMS: A form of life that can be seen under a microscope. Germs are microorganisms.

MODELS: Represents a living system and used in research.

MUCOCILIARY CLEARANCE: In the airways of the lungs, this system works to move mucus and particles breathed in to upper airways so they can be coughed out of the lungs.

MUCOID: Resembling mucus; forming large moist sticky colonies of bacteria.

MUCOSAL: A fluid made by mucous membranes and glands. Normally thin and slippery. In CF, mucus is thick and sticky.

MUCUS: A fluid made by membranes and glands. Mucus is normally thin and slippery. In CF, the mucus is often thick and sticky (see GLAND, MUCUS MEMBRANE, PHLEGM and SPUTUM).

MUCUS MEMBRANE: Tissue that contains mucus-making glands. Mucus membranes are found in the nose, mouth, lungs, esophagus, stomach, and intestines (see ESOPHAGUS, GLAND, INTESTINE, MUCUS and TISSUE).

MULTI-CENTER: More than one medical or research institution, such as a multi-center clinical study.

MULTIPLE BREATH WASHOUT: A test of lung function technique that measures the amount of obstruction or blockage in the airways. For this test, which can be used in people of all ages, the patient inhales a special gas mixture during normal relaxed breathing. The time that it takes for gas to wash out of the lung is measured and used to calculate the lung clearance index (LCI) (see LUNG CLEARANCE INDEX).


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NSAIDS: Non Steroidal Anti-Inflammatory Drugs, such as ibuprofen and aspirin (see ANTI-INFLAMMATORY AGENT).

NATIONAL INSTITUTES OF HEALTH (NIH): The agency of the U.S. Department of Health and Human Services (DHHS) responsible for health and medical research. NIH conducts research in its own laboratories and funds billions of dollars in research at other facilities, including universities, in the United States and abroad.

NEUTROPHIL: A white blood cell that destroys foreign bacteria in the body.

NEW DRUG APPLICATION (NDA): An application for a new drug submitted to the FDA to review and approve an experimental drug. The application is submitted after the completion of clinical trials and before a drug can be available to the general public.

NONINVASIVE: Not penetrating the body, as by incision. Used to describe a diagnostic procedure that does not invade healthy tissue.

NOVEL TECHNIQUE: A newly used skill or procedure.

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OBSTRUCTED: To block, make difficult to pass.

OFF-LABEL USE: When a drug is prescribed for conditions other than those approved by the FDA.

OPEN-LABEL TRIAL: A clinical trial where all parties, including physicians and participants, know if they are using an investigational drug. Also when all participants get to receive the investigational drug once its safety and effectiveness have been established and before the FDA approves it.

ORAL: Taken by mouth.

ORAL GLUCOSE TOLERANCE TEST (OGTT): This test is used to diagnose not just diabetes and CFRD but also the varied types of abnormal glucose tolerance in CF. You must first fast (nothing to eat or drink) for 12 hours. Then, blood is drawn to measure your “baseline” or “fasting” glucose level. You are then asked to drink glucose. Your blood sugar is measured again 2 hours later. Often, blood sugar is measured at 1, 2, and 3 hours later.

ORGAN: A part of the body that performs a specific function or group of functions. Some common organs are the heart, lungs, and brain. A group of related organs is an organ system, such as the digestive system.

ORGANISM: A form of life, such as a plant, animal, bacterium (single bacteria) or fungus.

ORPHAN DRUGS: An FDA category of medications used to treat rare diseases and conditions which affect fewer than 200,000 people. Orphan drug status gives a drug manufacturer a greater financial incentive to develop and provide such drugs. CF is an orphan disease.

OSCILLOMETRY: Measurement of changes, used in studying cardiovascular and respiratory functions.

OUTCOME: Overall results of a study or trial offered up for evaluation. Also called an endpoint.

OXIDANT: A substance that oxidizes another substance.

OXIDIZES: To combine with oxygen.

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PANCREAS: A long organ with glands found behind the stomach. The pancreas secretes enzymes through ducts into the intestine to break down food. In CF, mucus may obstruct the pancreatic ducts, preventing digestion. Another part of the pancreas has endocrine tissue, which makes a hormone called insulin. Insulin controls storage and use of sugar (see ENZYMES and MUCUS).

PANCREATIC INSUFFICIENCY (PI): The failure to properly digest food due to a lack of digestive enzymes made by the pancreas.

PARALLEL TRACK TRIAL: A system of making experimental drugs available to individuals who are unable to participate in clinical trials.

PARAMETER: Used to measure the quantity or function of something. Example: FEV1 is a measurement, or parameter, for lung function.

PEER REVIEW: Careful review of a clinical trial by experts who consider its scientific merit, participant safety and ethics.

PHARMACOKINETICS: The processes (in a living organism) of absorption, distribution, metabolism, and excretion of a drug or vaccine.

PHASE 1 TRIALS: First step in drug development to test a drug’s safety and to find out how the human body reacts to the drug. The purpose of Phase 1 trials is to discover the side effects of increased doses and collect early evidence of drug effectiveness. Healthy volunteers or people who do not have the disease or condition being studied, are often included.

PHASE 2 TRIALS: Research that tests the effectiveness and safety of a new drug. Identifies common side effects and risks.

PHASE 3 TRIALS: Usually the last type of clinical trial before a drug is approved by the FDA. Intended to gather more information about 1) the general risk-benefit of the drug, and 2) how to administer the drug (see RISK-BENEFIT).

PHASE 4 TRIALS: Research conducted after FDA approval to get additional information about the drug’s long-term risks, benefits, and best possible use.

PHLEGM: Mucus made from glands in the airways of the lung.

PLACEBO: A pharmaceutical preparation that contains no active substance (a sugar pill), and looks like the drug that is being tested.

PLACEBO CONTROLLED: A drug is studied by giving an inactive substance (a placebo) to one group of participants, while the drug being tested is given to another.

PLACEBO EFFECT: A change that occurs after a person takes a placebo.

PNEUMONIA: An inflammation of the lungs often caused by a bacterial or viral infection. Pneumonia is a problem in people with CF.

POLYMERASE CHAIN REACTION (PCR): A laboratory technique for quickly fusing large amounts of DNA together from a single DNA segment.

PORCINE: Of or derived from pigs.

PRECLINICAL: Testing of experimental drugs in the test tube or in animals. Occurs before clinical trials in humans are done.

PREVENTION TRIALS or STUDIES: Research to find better ways to prevent disease in people who have never had the disease or prevent disease from returning.

PRINCIPAL INVESTIGATOR (PI): Person responsible for the conduct of the clinical trial at a research site.

PROCEDURE: Something done to fix a health problem or learn more about it. For example, surgery, tests and putting in an IV (intravenous line) are procedures.

PROTEIN: Proteins are a basic part of all living cells. Found in foods such as meat, proteins are essential in the diet for growth and repair of tissue.

PROTOCOL: A detailed plan for a clinical trial. It describes what types of people may participate in the trial; the schedule of tests, procedures, medications and dosages; and the length of the study.

PSEUDOMONAS AERUGINOSA: A type of bacteria that often lives in the lungs of people with CF and causes lung infections (see ANTIBIOTIC, BACTERIA and STAPHYLOCOCCUS AUREUS).

PULMONARY: Relating to the lungs.

PULMONARY FUNCTION TESTS (PFTs): Tests to check lung function. Along with the patient’s history and physical exam, PFTs help doctors diagnose a health problem, and decide what therapy to prescribe. They can be used with children five years and older. PFTs measure air flow and lung volumes.

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QUALITY OF LIFE: A concept that considers a person’s physical, mental, and emotional health, level of independence, social relationships, personal beliefs and relationship to their environment.

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RANDOMIZATION: Commonly used to assign clinical trial participants to a treatment arm, based on chance (see ARM).

RANDOMIZED TRIAL: Participants are assigned by chance to one of two or more treatment arms of a clinical trial (see ARM).

RECRUITMENT: Act of enrolling people in a clinical trial.

RECRUITMENT PERIOD: Time frame allowed to recruit for a clinical trial.

REPRODUCIBLE: To make a counterpart, image, or copy. To produce again or anew. To re-create. In clinical research, it refers to the ability of one study to recreate the results of a different study, thereby showing that the results are valid.


Applied Research
Studies that apply basic research findings to problems like diseases and symptoms. Examples: creating new respiratory equipment or studying cell defects in the sweat glands of people with CF (see CELL and GLAND).

Basic Science Research
Studies that increase knowledge of basic life processes. To learn the causes of CF, scientists do basic science studies like gene studies and research on how cells work (see CELL, GENE and GENETIC).

Clinical Research
Studies in people that improve diagnosis and treatment. Examples: studies on drugs, lung function, nutrition, and sweating. (see DIAGNOSE, PULMONARY FUNCTION TESTS and SWEAT TEST).

RESEARCH COORDINATOR: A staff person chosen by the principal investigator to assist him/her in conducting the clinical trial (see PRINCIPAL INVESTIGATOR).

RESISTANCE: The ability of an organism to defend itself, either from disease or from being harmed. Example: bacteria can become resistant to antibiotics and no longer be killed by the drugs.

RISK-BENEFIT RATIO: The known risk of participating in a clinical trial weighed against the potential benefits.

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SAFETY: The condition or state of being safe. In clinical trials, this refers to an absence of harmful side effects resulting from use of the product and may be assessed by special tests and procedures, psychiatric evaluation, and/or physical examination of participants.

SAFETY PROFILE: A summary of clinical data that explains the possible side effects of a certain drug or treatment.

SCREENING: Identifying a potential clinical trial participant by finding out if the person meets the eligibility criteria (see ELIGIBILITY CRITERIA).

SCREENING STUDIES: Refers to studies that test how to identify diseases or conditions.

SECRETION: A product of a gland, like sweat or saliva (see GLAND).

SENSITIVE: Responsive to a stimulus. Easily irritated or inflamed.

SIDE EFFECTS: Any unexpected results from taking an investigational drug or treatment (see ADVERSE REACTION).

SINGLE BLIND TRIAL: A trial where either the investigator or participant is unaware of which treatment arm the participant is assigned to (see BLIND TRIAL, DOUBLE BLIND TRIAL and ARM).

SPACER DEVICE: A hollow chamber that fits on the mouthpiece of a metered dose inhaler. It makes the inhaler easier to use and more efficient in delivering medicine.

SPIROMETER: A device that measures air flow and lung volumes (see PULMONARY FUNCTION TESTS).

SPONSOR: Individual, company, institution or organization responsible for initiation, management and financing of a study.

SPUTUM: Mucus or phlegm coughed up from lungs (see MUCUS and PHLEGM).

SPUTUM CULTURE: A test to see what germs may be growing in the sputum (see SPUTUM).

SPUTUM DENSITY: A measurement of mucus or phlegm coughed up from lungs.

STANDARD TREATMENT: An effective treatment or drug approved by the FDA for a specific disease or condition.

STANDARD OF CARE: Treatment or medical management based on state-of-the-art health care (see STANDARD TREATMENT).

STAPHYLOCOCCUS AUREUS (STAPH): A type of bacteria that can cause infections. In CF, “staph” often causes lung infections. It is treated with antibiotics (see ANTIBIOTIC and BACTERIA).

STATISTICAL SIGNIFICANCE: The probability that an event or change did or did not occur by chance.

STUDY ENDPOINT: Results from a clinical trial used to judge the effectiveness of a drug treatment (see OUTCOME).

SUB-STUDY: A smaller study that is part of a larger study.

SURFACTANT: A chemical that can reduce the surface tension of a liquid in which it is dissolved so that it spreads out more easily.

SUSCEPTIBILITY: Being prone to, sensitive to, or lacking the ability to resist something.

SWEAT TEST: A test to diagnose CF. Measures the salt (sodium and chloride) in sweat.

SYSTEMIC: Affecting the body as a whole.

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THERAPEUTIC: Refers to a substance that has a healing effect on a specific condition.

TISSUE: A group of cells of a similar type and function.

TOLERABILITY: Ability to tolerate, put up with, or endure.

TOLERABLE DOSAGE: Highest recommended amount of a substance that does not have adverse results (see ADVERSE REACTION and SIDE EFFECTS).

TOXICITY: The degree to which a drug is harmful or poisonous. A drug’s toxicity will vary depending on amount and use.

TREATMENT IND: IND stands for Investigational New Drug, and is part of the FDA’s approval process to market a new prescription drug. This process makes promising investigational drugs available to patients outside of clinical trials early in the drug development process, before the FDA approves it as a new drug.

TREATMENT TRIALS: Refers to trials that test new drugs, new combinations of drugs, or new approaches to standard medical treatments.

TRIGGER: A device used to release or activate a mechanism. An event that causes other events to happen.

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UNDUE OR UNNECESSARY RISK: IRBs review clinical trial protocols to ensure participants are not required to do anything that would be harmful to their health (see INSTITUTIONAL REVIEW BOARDS).

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VALIDATE: To confirm or make true. To give official sanction or approval. In clinical trials, it is the process by which the correctness of data are established.

VIRUS: An organism, smaller than bacteria, that causes infections like influenza, viral pneumonia, colds, and hepatitis (see BACTERIA and PNEUMONIA).

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WASHOUT PERIOD: A time during a clinical trial when participants receive no drugs for the study so the effects of previous study drugs are removed.

WITHDRAW: The point at which a clinical trial participant, for any reason, stops participating in the trial.

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Glossary Sources

• An Introduction to Cystic Fibrosis For Patients and Families, 5th Edition; 2003, Cystic Fibrosis Foundation Glossary of Clinical Trials Terms, from National Institutes of Health


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