Defining the biologic and physiologic trajectory of presymptomatic through advanced pulmonary fibrosis - PROJECT SUMMARY/ABSTRACT
Pulmonary fibrosis (PF) is prevalent among 200,000 persons in the USA, a figure that is increasing. Most
individuals present with progressive dyspnea and/or cough, and have moderately advanced disease with
irreversible fibrosis at the time of diagnosis. Treatment of PF at an earlier (pre-clinical) stage would result in a
greater reduction in the overall burden of morbidity, but limited understanding of the early natural history,
including the biological and clinical progression, remains a barrier to accomplishing this goal. To improve the
understanding of the earliest stages of PF, >450 asymptomatic relatives of persons with familial PF have
undergone serial screening high resolution CT (HRCT) scans to detect pre-clinical PF, as part of an ongoing
prospective cohort study. When defined by the new development or progression of abnormal changes of the
pulmonary parenchyma (“interstitial lung abnormalities” [ILA]), pre-clinical PF is observed in approximately
20% of participants. While having ILA on the first screening HRCT is a major risk factor for progression, almost
half of pre-clinical PF comprised new development of ILA, underscoring the need for additional biomarkers of
early disease. Altered gene expression in the peripheral blood precedes pre-clinical progression in this cohort,
and may represent a promising biomarker. Clinically, among those participants progressing through pre-clinical
PF (toward clinically-diagnosed PF), the observed pattern of progressive physiologic decay appears to be
disease stage-specific and occurs in a manner that may be shared across individuals with PF. Importantly, the
forced vital capacity (FVC) undergoes very little change during pre-clinical PF. The FVC is used to monitor for
PF progression and has been the primary endpoint in successful trials of disease modifying therapy for PF.
Therefore, alternative endpoints/outcome measures are needed in order to study disease modification in pre-
clinical PF. The overall hypothesis is that PF follows a sequenced progression, including blood biomarkers
(transcriptomic and/or proteins) indicative of early pathobiology and predictive of pre-clinical progression, and a
stage-specific, sequenced decay in key physiologic parameters. The following Specific Aims are proposed: (1)
Define a blood biomarker signature to predict progressive pre-clinical PF; and (2) Develop a disease
progression model (DPM) to describe the physiologic decay across all stages of PF. Disease-specific DPMs
have been used to measure disease modification such that detection of a treatment effect is subject-specific, a
more powerful alternative to analysis without regard to stage-specific progression expectations. The working
hypotheses will be tested during continued observation of the prospective pre-clinical PF cohort and several
cohorts of patients with established PF. Completion of these Aims is an important step toward a long-term
programmatic goal (of the investigators and the NHLBI) to speed development of new disease modifying
therapy for PF, particularly those capable of preventing or delaying symptom onset.