Cystic fibrosis & clinical trials

A plain language glossary

Welcome to our glossary. This glossary explains words that are often used in clinical trials and research studies in cystic fibrosis.

We hope the glossary will be useful for people in the cystic fibrosis community who want to learn more about clinical trials. We also hope the glossary helps research teams who write about clinical trials.

Find out more about our glossary.

Adverse event

Any health problem that happens during a clinical trial.

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Amplifier

A type of CFTR modulator that increases how many CFTR doorway proteins a cell makes.

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Biomarkers

Biomarkers, or biological markers, are signs that tell us something about the body. Examples include blood pressure, sputum, or levels of chemicals in the blood and urine.

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Blinding

Blinding is when researchers, clinical trial participants, or both don't know who is receiving which treatment until near the end of the trial.

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Body mass index (BMI)

A way of measuring a person’s weight compared to their height.

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CFQR

A questionnaire that measures how cystic fibrosis impacts quality of life, including health, daily life, well-being, and CF symptoms.

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CFTR modulator

CFTR modulators are medicines that treat underlying faults with the CFTR doorway protein.

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Clinical trial

A project to study if a new treatment or a different treatment routine is safe and improves the target health problem.

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Coefficient of fat absorption (CFA)

The coefficient of fat absorption (CFA) is how much fat a person absorbs from their food into their body. It is written as a percentage.

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Concomitant

Concomitant means at the same time.

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Corrector

A type of CFTR modulator medicine that helps correct the shape of faulty CFTR doorway proteins.

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Cystic fibrosis transmembrane conductance regulator (CFTR)

A protein forming a channel or doorway on the cell surface that lets chloride (a component of salt) move out of the cell.

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Double-blind

See blinding

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Efficacy

Efficacy is how well the treatment improves a person's health in clinical trials.

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Forced expiratory flow (FEF)

Forced expiratory flow (FEF) is the speed that someone can breathe out air from their lungs, measured in the middle of a hard, fast breath out.

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Forced vital capacity (FVC)

Forced vital capacity (FVC) is how much air a person breathes out in a lung function test.

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Gating mutations

Genes with gating mutations instruct cells to make CFTR protein doorways that are mostly locked shut.

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Genes

Instructions that help cells do their job.

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Lung clearance index (LCI)

The lung clearance index (LCI) is a score of how well air moves through a person's lungs.

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Masking / masked

Another name for blinding

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Minimal function mutations

Genes with minimal function mutations instruct cells to make CFTR protein doorways that do not work, or only a little.

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Mucociliary clearance

How tiny hairs on cells lining the airway sweep mucus up and out of the airway.

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Mucolytic

A medicine that breaks down mucus.

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Multiple breath washout (MBW)

A way to measure LCI score.

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Mutation

A change in a gene code, meaning the gene gives faulty instructions to the cell.

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Nasal transepithelial potential difference (NPD)

A tiny electrical current in the nose linked to the movement of salt across cells.

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Nonsense mutations

Genes with nonsense mutations instruct cells to produce unfinished CFTR doorways.

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Outcome measure

Outcome measures are assessments that happen during clincial trials.

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Percent predicted forced expiratory volume (ppFEV1)

A measure showing how well a person’s lungs work.

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Pharmacodynamics

Pharmacodynamics describes what a medicine does to the body.

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Pharmacokinetic study (PK study)

Pharmacokinetics describes what happens to a medicine in a person's body in the hours and days after they take it.

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Placebo

A placebo is a "fake" treatment, usually made of sugar.

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Potentiator

A type of CFTR modulator medicine that helps to keep faulty CFTR doorways open.

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Pulmonary exacerbation rate

The number of times in a year that a lung infection makes CF worse.

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Residual function mutations

Genes with residual function mutations instruct cells to make fewer or faulty CFTR doorways.

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Side effect

Another name for adverse event

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Single-blind

See blinding

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Sweat chloride

How much chloride is in a person’s sweat. People with CF have more chloride in their sweat. Measuring sweat chloride can help show if someone has CF .

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Washout period

The length of time a clinical trial participant has to stop taking a medicine, before starting to take the experimental medicine.

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Z-score

A score of how a person compares to average in a population. It is used to compare different characteristics, for example, their BMI or their height.

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