TABLE 1.

OVERVIEW OF CYSTIC FIBROSIS OUTCOME MEASURES

Outcome Measures	Description
Clinical efficacy measures
Definition	A characteristic or variable that reflects how a patient feels, functions, or survives
Examples	Pulmonary exacerbations, intravenous antibiotic usage, hospitalizations, anthropometric measures (height and weight), PROs, quality of life
Surrogate endpoints
Definition	A laboratory measurement or physical sign that is used in therapeutic trials as a substitute for a clinically meaningful endpoint that is a direct measure of how a patient feels, functions, or survives and is expected to predict the effect of therapy.
Examples	FEV1, CT, infant pulmonary function
Biomarkers
Definition	A characteristic that is objectively measured and evaluated as an indicator of normal biologic process, pathogenic process, or pharmacologic response to a therapeutic intervention.
Examples	Bacterial density, inflammatory markers, CFTR functional measures (nasal potential difference, sweat chloride, airway surface liquid height), mucociliary clearance

Definition of abbreviations: CFTR = cystic fibrosis transmembrane conductance regulator; CT = computed tomography; PROs = patient-reported outcomes.