Lisa H. Lancaster

A phase 3 trial of pirfenidone in patients with idiopathic pulmonary fibrosis.

BACKGROUND In two of three phase 3 trials, pirfenidone, an oral antifibrotic therapy, reduced disease progression, as measured by the decline in forced vital capacity (FVC) or vital capacity, in patients with idiopathic pulmonary fibrosis; in the third trial, this end point was not achieved. We sought to confirm the beneficial effect of pirfenidone on disease progression in such patients. METHODS In this phase 3 study, we randomly assigned 555 patients with idiopathic pulmonary fibrosis to receive either oral pirfenidone (2403 mg per day) or placebo for 52 weeks. The primary end point was the change in FVC or death at week 52. Secondary end points were the 6-minute walk distance, progression-free survival, dyspnea, and death from any cause or from idiopathic pulmonary fibrosis. RESULTS In the pirfenidone group, as compared with the placebo group, there was a relative reduction of 47.9% in the proportion of patients who had an absolute decline of 10 percentage points or more in the percentage of the predicted FVC or who died; there was also a relative increase of 132.5% in the proportion of patients with no decline in FVC (P<0.001). Pirfenidone reduced the decline in the 6-minute walk distance (P=0.04) and improved progression-free survival (P<0.001). There was no significant between-group difference in dyspnea scores (P=0.16) or in rates of death from any cause (P=0.10) or from idiopathic pulmonary fibrosis (P=0.23). However, in a prespecified pooled analysis incorporating results from two previous phase 3 trials, the between-group difference favoring pirfenidone was significant for death from any cause (P=0.01) and from idiopathic pulmonary fibrosis (P=0.006). Gastrointestinal and skin-related adverse events were more common in the pirfenidone group than in the placebo group but rarely led to treatment discontinuation. CONCLUSIONS Pirfenidone, as compared with placebo, reduced disease progression, as reflected by lung function, exercise tolerance, and progression-free survival, in patients with idiopathic pulmonary fibrosis. Treatment was associated with an acceptable side-effect profile and fewer deaths. (Funded by InterMune; ASCEND ClinicalTrials.gov number, NCT01366209.).

Short telomeres are a risk factor for idiopathic pulmonary fibrosis

Idiopathic interstitial pneumonias (IIPs) have a progressive and often fatal course, and their enigmatic etiology has complicated approaches to effective therapies. Idiopathic pulmonary fibrosis (IPF) is the most common of IIPs and shares with IIPs an increased incidence with age and unexplained scarring in the lung. Short telomeres limit tissue renewal capacity in the lung and germ-line mutations in telomerase components, hTERT and hTR, underlie inheritance in a subset of families with IPF. To examine the hypothesis that short telomeres contribute to disease risk in sporadic IIPs, we recruited patients who have no family history and examined telomere length in leukocytes and in alveolar cells. To screen for mutations, we sequenced hTERT and hTR. We also reviewed the cases for features of a telomere syndrome. IIP patients had shorter leukocyte telomeres than age-matched controls (P < 0.0001). In a subset (10%), IIP patients had telomere lengths below the first percentile for their age. Similar to familial cases with mutations, IPF patients had short telomeres in alveolar epithelial cells (P < 0.0001). Although telomerase mutations were rare, detected in 1 of 100 patients, we identified a cluster of individuals (3%) with IPF and cryptogenic liver cirrhosis, another feature of a telomere syndrome. Short telomeres are thus a signature in IIPs and likely play a role in their age-related onset. The clustering of cryptogenic liver cirrhosis with IPF suggests that the telomere shortening we identify has consequences and can contribute to what appears clinically as idiopathic progressive organ failure in the lung and the liver.

Genome-wide association study identifies multiple susceptibility loci for pulmonary fibrosis

We performed a genome-wide association study of non-Hispanic, white individuals with fibrotic idiopathic interstitial pneumonias (IIPs; n = 1,616) and controls (n = 4,683), with follow-up replication analyses in 876 cases and 1,890 controls. We confirmed association with TERT at 5p15, MUC5B at 11p15 and the 3q26 region near TERC, and we identified seven newly associated loci (Pmeta = 2.4 × 10−8 to 1.1 × 10−19), including FAM13A (4q22), DSP (6p24), OBFC1 (10q24), ATP11A (13q34), DPP9 (19p13) and chromosomal regions 7q22 and 15q14-15. Our results suggest that genes involved in host defense, cell-cell adhesion and DNA repair contribute to risk of fibrotic IIPs.

Ascertainment of Individual Risk of Mortality for Patients with Idiopathic Pulmonary Fibrosis

RATIONALE Several predictors of mortality in patients with idiopathic pulmonary fibrosis have been described; however, there is a need for a practical and accurate method of quantifying the prognosis of individual patients. OBJECTIVES Develop a practical mortality risk scoring system for patients with idiopathic pulmonary fibrosis. METHODS We used a Cox proportional hazards model and data from two clinical trials (n = 1,099) to identify independent predictors of 1-year mortality among patients with idiopathic pulmonary fibrosis. From the comprehensive model, an abbreviated clinical model comprised of only those predictors that are readily and reliably ascertained by clinicians was derived. Beta coefficients for each predictor were then used to develop a practical mortality risk scoring system. MEASUREMENTS AND MAIN RESULTS Independent predictors of mortality included age, respiratory hospitalization, percent predicted FVC, 24-week change in FVC, percent predicted carbon monoxide diffusing capacity, 24-week change in percent predicted carbon monoxide diffusing capacity, and 24-week change in health-related quality of life. An abbreviated clinical model comprising only four predictors (age, respiratory hospitalization, percent predicted FVC, and 24-wk change in FVC), and the corresponding risk scoring system produced estimates of 1-year mortality risk consistent with observed data (9.9% vs. 9.7%; C statistic = 0.75; 95% confidence interval, 0.71–0.79). CONCLUSIONS The prognosis for patients with idiopathic pulmonary fibrosis may be accurately determined using four readily ascertainable predictors. Our simplified scoring system may be a valuable tool for determining prognosis and guiding clinical management. Additional research is needed to validate the applicability and accuracy of the scoring system.

Six-minute-walk test in idiopathic pulmonary fibrosis: test validation and minimal clinically important difference.

RATIONALE The 6-minute-walk test (6MWT) is a practical and clinically meaningful measure of exercise tolerance with favorable performance characteristics in various cardiac and pulmonary diseases. Performance characteristics in patients with idiopathic pulmonary fibrosis (IPF) have not been systematically evaluated. OBJECTIVES To assess the reliability, validity, and responsiveness of the 6MWT and estimate the minimal clinically important difference (MCID) in patients with IPF. METHODS The study population included all subjects completing a 6MWT in a clinical trial evaluating interferon gamma-1b (n = 822). Six-minute walk distance (6MWD) and other parameters were measured at baseline and at 24-week intervals using a standardized protocol. Parametric and distribution-independent correlation coefficients were used to assess the strength of the relationships between 6MWD and measures of pulmonary function, dyspnea, and health-related quality of life. Both distribution-based and anchor-based methods were used to estimate the MCID. MEASUREMENTS AND MAIN RESULTS Comparison of two proximal measures of 6MWD (mean interval, 24 d) demonstrated good reliability (coefficient = 0.83; P < 0.001). 6MWD was weakly correlated with measures of physiologic function and health-related quality of life; however, values were consistently and significantly lower for patients with the poorest functional status, suggesting good construct validity. Importantly, change in 6MWD was highly predictive of mortality; a 24-week decline of greater than 50 m was associated with a fourfold increase in risk of death at 1 year (hazard ratio, 4.27; 95% confidence interval, 2.57- 7.10; P < 0.001). The estimated MCID was 24-45 m. CONCLUSIONS The 6MWT is a reliable, valid, and responsive measure of disease status and a valid endpoint for clinical trials in IPF.

Forced vital capacity in patients with idiopathic pulmonary fibrosis: test properties and minimal clinically important difference.

RATIONALE Forced vital capacity (FVC) is an established measure of pulmonary function in idiopathic pulmonary fibrosis (IPF). Evidence regarding its measurement properties and minimal clinically important difference (MCID) in this population is limited. OBJECTIVES To assess the reliability, validity, and responsiveness of FVC and estimate the MCID in patients with IPF. METHODS The study population included all 1,156 randomized patients in two clinical trials of IFN-γ1b. FVC and other measures of functional status were measured at screening or baseline and 24-week intervals thereafter. Reliability was assessed based on two proximal measures of FVC, validity was assessed based on correlations between FVC and other measures of functional status, and responsiveness was assessed based on the relationship between 24-week changes in FVC and other measures of functional status. Distribution-based and anchor-based methods were used to estimate the MCID. MEASUREMENTS AND MAIN RESULTS Correlation of percent-predicted FVC between measurements (mean interval, 18 d) was high (r = 0.93; P < 0.001). Correlations between FVC and other parameters were generally weak, with the strongest observed correlation between FVC and carbon monoxide diffusing capacity (r = 0.38; P < 0.001). Correlations between change in FVC and changes in other parameters were slightly stronger (range, r = 0.16-0.37; P < 0.001). Importantly, 1-year risk of death was more than twofold higher (P < 0.001) in patients with a 24-week decline in FVC between 5% and 10%. The estimated MCID was 2-6%. CONCLUSIONS FVC is a reliable, valid, and responsive measure of clinical status in patients with IPF, and a decline of 2-6%, although small, represents a clinically important difference.

Obstructive Sleep Apnea Is Common in Idiopathic Pulmonary Fibrosis

BACKGROUND From 1984 to 2006, studies of sleep in patients with interstitial lung disease revealed disturbed sleep, frequent nocturnal desaturations, nocturnal cough, and obstructive sleep apnea (OSA). Our goal was to analyze OSA in an outpatient population of stable patients with idiopathic pulmonary fibrosis (IPF). METHODS Patients with IPF who had been followed up in the Vanderbilt Pulmonary Clinic were asked to participate. All patients were given a diagnosis of IPF by the 2000 American Thoracic Society consensus statement criteria. Subjects completed an Epworth sleepiness scale (ESS) questionnaire and a sleep apnea scale of sleep disorders questionnaire (SA-SDQ) before undergoing nocturnal polysomnography (NPSG). OSA was defined as an apnea-hypopnea index (AHI) of > 5 events per hour. RESULTS Fifty subjects enrolled and completed a NPSG. The mean age was 64.9 years, and the mean BMI was 32.3. OSA was diagnosed in 88% of subjects. Ten subjects (20%) had mild OSA (AHI, 5 to 15 events per hour), and 34 subjects (68%) had moderate-to-severe OSA (AHI, > 15 events per hour). Only 6 subjects (12%) had a normal AHI. One patient was asymptomatic as determined by ESS and SA-SDQ, but had an AHI of 24 events per hour. The sensitivity of the ESS was 75% with a specificity of 15%, whereas the SA-SDQ had a sensitivity of 88% with a specificity of 50%. BMI did not correlate strongly with AHI (r = 0.30; p = 0.05). CONCLUSIONS OSA is prevalent in patients with IPF and may be underrecognized by primary care providers and specialists. Neither ESS nor SA-SDQ alone or in combination was a strong screening tool. Given the high prevalence found in our sample, formal sleep evaluation and polysomnography should be considered in patients with IPF.

Viral Infection in Acute Exacerbation of Idiopathic Pulmonary Fibrosis

RATIONALE Idiopathic pulmonary fibrosis is a progressive, uniformly fatal interstitial lung disease. An acute exacerbation of idiopathic pulmonary fibrosis is an episode of acute respiratory worsening without an identifiable etiology. Occult viral infection has been proposed as a possible cause of acute exacerbation. OBJECTIVES To use unbiased genomics-based discovery methods to define the role of viruses in acute exacerbation of idiopathic pulmonary fibrosis. METHODS Bronchoalveolar lavage and serum from patients with acute exacerbation of idiopathic pulmonary fibrosis, stable disease, and acute lung injury were tested for viral nucleic acid using multiplex polymerase chain reaction, pan-viral microarray, and high-throughput cDNA sequencing. MEASUREMENTS AND MAIN RESULTS Four of forty-three patients with acute exacerbation of idiopathic pulmonary fibrosis had evidence of common respiratory viral infection (parainfluenza [n = 1], rhinovirus [n = 2], coronavirus [n = 1]); no viruses were detected in the bronchoalveolar lavage from stable patients. Pan-viral microarrays revealed additional evidence of viral infection (herpes simplex virus [n = 1], Epstein-Barr virus [n = 2], and torque teno virus [TTV] [n = 12]) in patients with acute exacerbation. TTV infection was significantly more common in patients with acute exacerbation than stable controls (P = 0.0003), but present in a similar percentage of acute lung injury controls. Deep sequencing of a subset of acute exacerbation cases confirmed the presence of TTV but did not identify additional viruses. CONCLUSIONS Viral infection was not detected in most cases of acute exacerbation of idiopathic pulmonary fibrosis. TTV was present in a significant minority of cases, and cases of acute lung injury; the clinical significance of this finding remains to be determined.

RARE VARIANTS IN RTEL1 ARE ASSOCIATED WITH FAMILIAL INTERSTITIAL PNEUMONIA

RATIONALE Up to 20% of cases of idiopathic interstitial pneumonia cluster in families, comprising the syndrome of familial interstitial pneumonia (FIP); however, the genetic basis of FIP remains uncertain in most families. OBJECTIVES To determine if new disease-causing rare genetic variants could be identified using whole-exome sequencing of affected members from FIP families, providing additional insights into disease pathogenesis. METHODS Affected subjects from 25 kindreds were selected from an ongoing FIP registry for whole-exome sequencing from genomic DNA. Candidate rare variants were confirmed by Sanger sequencing, and cosegregation analysis was performed in families, followed by additional sequencing of affected individuals from another 163 kindreds. MEASUREMENTS AND MAIN RESULTS We identified a potentially damaging rare variant in the gene encoding for regulator of telomere elongation helicase 1 (RTEL1) that segregated with disease and was associated with very short telomeres in peripheral blood mononuclear cells in 1 of 25 families in our original whole-exome sequencing cohort. Evaluation of affected individuals in 163 additional kindreds revealed another eight families (4.7%) with heterozygous rare variants in RTEL1 that segregated with clinical FIP. Probands and unaffected carriers of these rare variants had short telomeres (<10% for age) in peripheral blood mononuclear cells and increased T-circle formation, suggesting impaired RTEL1 function. CONCLUSIONS Rare loss-of-function variants in RTEL1 represent a newly defined genetic predisposition for FIP, supporting the importance of telomere-related pathways in pulmonary fibrosis.

Bronchoscopic Cryobiopsy for the Diagnosis of Diffuse Parenchymal Lung Disease

Background Although in some cases clinical and radiographic features may be sufficient to establish a diagnosis of diffuse parenchymal lung disease (DPLD), surgical lung biopsy is frequently required. Recently a new technique for bronchoscopic lung biopsy has been developed using flexible cryo-probes. In this study we describe our clinical experience using bronchoscopic cryobiopsy for diagnosis of diffuse lung disease. Methods A retrospective study of subjects who had undergone bronchoscopic cryobiopsy for evaluation of DPLD at an academic tertiary care center from January 1, 2012 through January 15, 2013 was performed. The procedure was performed using a flexible bronchoscope to acquire biopsies of lung parenchyma. H&E stained biopsies were reviewed by an expert lung pathologist. Results Twenty-five eligible subjects were identified. With a mean area of 64.2 mm2, cryobiopsies were larger than that typically encountered with traditional transbronchial forceps biopsy. In 19 of the 25 subjects, a specific diagnosis was obtained. In one additional subject, biopsies demonstrating normal parenchyma were felt sufficient to exclude diffuse lung disease as a cause of dyspnea. The overall diagnostic yield of bronchoscopic cryobiopsy was 80% (20/25). The most frequent diagnosis was usual interstitial pneumonia (UIP) (n = 7). Three of the 25 subjects ultimately required surgical lung biopsy. There were no significant complications. Conclusion In patients with suspected diffuse parenchymal lung disease, bronchoscopic cryobiopsy is a promising and minimally invasive approach to obtain lung tissue with high diagnostic yield.