TrialLineage Concept
Forced vital capacity
Forced vital capacity (FVC) is a lung function measurement — the total volume of air a person can forcibly exhale after a full breath. In IPF clinical trials, the rate of FVC decline over time is the standard primary endpoint used to measure whether antifibrotic treatments are slowing disease progression.
What is FVC?
FVC is measured by spirometry — a standard pulmonary function test. The patient takes the deepest breath possible, then exhales as hard and completely as they can into a device that measures air volume. FVC reflects overall lung capacity and is sensitive to the restrictive physiology of fibrotic lung disease, where scarring reduces the lungs' ability to expand.
In IPF, FVC typically declines over time as fibrosis progresses. The annual rate of FVC decline (often measured in milliliters per year) has been validated by regulatory agencies as a surrogate endpoint that correlates with disease progression, quality of life, and mortality.
Connection to the IPF lineage
FVC decline rate is the primary endpoint of the BMS-986278 Phase 3 trial. The trial is designed to determine whether blocking LPA1 slows the rate at which patients lose lung function. The establishment of FVC decline as an accepted regulatory endpoint — validated through the pirfenidone and nintedanib trials — is what made it possible to design this study with a clear, measurable outcome.