Progressive Pulmonary Fibrosis and Interstitial Lung Abnormalities: AJR Expert Panel Narrative Review

Progressive pulmonary fibrosis (PPF) and interstitial lung abnormalities (ILA) are relatively new concepts in interstitial lung disease (ILD) imaging and clinical management. Recognition of signs of PPF, as well as identification and classification of ILA, are important tasks during chest high-resolution CT interpretation, to optimize management of patients with ILD and those at risk of developing ILD. However, following professional society guidance, the role of imaging surveillance remains unclear in stable patients with ILD, asymptomatic patients with ILA who are at risk of progression, and asymptomatic patients at risk of developing ILD without imaging abnormalities. In this AJR Expert Panel Narrative Review, we summarize the current knowledge regarding PPF and ILA and describe the range of clinical practice with respect to imaging patients with ILD, those with ILA, and those at risk of developing ILD. In addition, we offer suggestions to help guide surveillance imaging in areas with an absence of published guidelines, where such decisions are currently driven primarily by local pulmonologists' preference.

Computational Deconvolution of Cell Type-Specific Gene Expression in COPD and IPF Lungs Reveals Disease Severity Associations

RATIONALE

Chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF) are debilitating diseases associated with divergent histopathological changes in the lungs. At present, due to cost and technical limitations, profiling cell types is not practical in large epidemiology cohorts (n>1000). Here, we used computational deconvolution to identify cell types in COPD and IPF lungs whose abundances and cell type-specific gene expression are associated with disease diagnosis and severity.

METHODS

We analyzed lung tissue RNA-seq data from 1026 subjects (COPD, n=465; IPF, n=213; control, n=348) from the Lung Tissue Research Consortium. We performed RNA-seq deconvolution, querying thirty-eight discrete cell-type varieties in the lungs. We tested whether deconvoluted cell-type abundance and cell type-specific gene expression were associated with disease severity.

RESULTS

The abundance score of twenty cell types significantly differed between IPF and control lungs. In IPF subjects, eleven and nine cell types were significantly associated with forced vital capacity (FVC) and diffusing capacity for carbon monoxide (DLCO), respectively. Aberrant basaloid cells, a rare cells found in fibrotic lungs, were associated with worse FVC and DLCO in IPF subjects, indicating that this aberrant epithelial population increased with disease severity. Alveolar type 1 and vascular endothelial (VE) capillary A were decreased in COPD lungs compared to controls. An increase in macrophages and classical monocytes was associated with lower DLCO in IPF and COPD subjects. In both diseases, lower non-classical monocytes and VE capillary A cells were associated with increased disease severity. Alveolar type 2 cells and alveolar macrophages had the highest number of genes with cell type-specific differential expression by disease severity in COPD and IPF. In IPF, genes implicated in the pathogenesis of IPF, such as matrix metallopeptidase 7, growth differentiation factor 15, and eph receptor B2, were associated with disease severity in a cell type-specific manner.

CONCLUSION

Utilization of RNA-seq deconvolution enabled us to pinpoint cell types present in the lungs that are associated with the severity of COPD and IPF. This knowledge offers valuable insight into the alterations within tissues in more advanced illness, ultimately providing a better understanding of the underlying pathological processes that drive disease progression.

Meaningful Endpoints for Idiopathic Pulmonary Fibrosis (IPF) Clinical Trials: Emphasis on 'Feels, Functions, Survives'. Report of a Collaborative Discussion in a Symposium with Direct Engagement from Representatives of Patients, Investigators, the National Institutes of Health, a Patient Advocacy Organization, and a Regulatory Agency

Background: Idiopathic pulmonary fibrosis (IPF) carries significant mortality and unpredictable progression, with limited therapeutic options. Designing trials with patient-meaningful endpoints, enhancing the reliability and interpretability of results, and streamlining the regulatory approval process are of critical importance to advancing clinical care in IPF. Methods: A landmark in-person symposium in June 2023 assembled 43 participants from the US and internationally, including patients with IPF, investigators, and regulatory representatives, to discuss the immediate future of IPF clinical trial endpoints. Patient advocates were central to discussions, which evaluated endpoints according to regulatory standards and the FDA's 'feels, functions, survives' criteria. Results: Three themes emerged: 1) consensus on endpoints mirroring the lived experiences of patients with IPF; 2) consideration of replacing forced vital capacity (FVC) as the primary endpoint, potentially by composite endpoints that include 'feels, functions, survives' measures or FVC as components; 3) support for simplified, user-friendly patient-reported outcomes (PROs) as either components of primary composite endpoints or key secondary endpoints, supplemented by functional tests as secondary endpoints and novel biomarkers as supportive measures (FDA Guidance for Industry (Multiple Endpoints in Clinical Trials) available at: https://www.fda.gov/media/162416/download). Conclusions: This report, detailing the proceedings of this pivotal symposium, suggests a potential turning point in designing future IPF clinical trials more attuned to outcomes meaningful to patients, and documents the collective agreement across multidisciplinary stakeholders on the importance of anchoring IPF trial endpoints on real patient experiences-namely, how they feel, function, and survive. There is considerable optimism that clinical care in IPF will progress through trials focused on patient-centric insights, ultimately guiding transformative treatment strategies to enhance patients' quality of life and survival.

Estimating the effect of nintedanib on forced vital capacity in children and adolescents with fibrosing interstitial lung disease using a Bayesian dynamic borrowing approach

BACKGROUND

The rarity of childhood interstitial lung disease (chILD) makes it challenging to conduct powered trials. In the InPedILD trial, among 39 children and adolescents with fibrosing ILD, there was a numerical benefit of nintedanib versus placebo on change in forced vital capacity (FVC) over 24 weeks (difference in mean change in FVC % predicted of 1.21 [95% confidence interval: -3.40, 5.81]). Nintedanib has shown a consistent effect on FVC across populations of adults with different diagnoses of fibrosing ILD.

METHODS

In a Bayesian dynamic borrowing analysis, prespecified before data unblinding, we incorporated data on the effect of nintedanib in adults and the data from the InPedILD trial to estimate the effect of nintedanib on FVC in children and adolescents with fibrosing ILD. The data from adults were represented as a meta-analytic predictive (MAP) prior distribution with mean 1.69 (95% credible interval: 0.49, 3.08). The adult data were weighted according to expert judgment on their relevance to the efficacy of nintedanib in chILD, obtained in a formal elicitation exercise.

RESULTS

Combined data from the MAP prior and InPedILD trial analyzed within the Bayesian framework resulted in a median difference between nintedanib and placebo in change in FVC % predicted at Week 24 of 1.63 (95% credible interval: -0.69, 3.40). The posterior probability for superiority of nintedanib versus placebo was 95.5%, reaching the predefined success criterion of at least 90%.

CONCLUSION

These findings, together with the safety data from the InPedILD trial, support the use of nintedanib in children and adolescents with fibrosing ILDs.

An adjudication algorithm for respiratory-related hospitalisation in idiopathic pulmonary fibrosis

Background

There is no standard definition of respiratory-related hospitalisation, a common end-point in idiopathic pulmonary fibrosis (IPF) clinical trials. As diverse aetiologies and complicating comorbidities can present similarly, external adjudication is sometimes employed to achieve standardisation of these events.

Methods

An algorithm for respiratory-related hospitalisation was developed through a literature review of IPF clinical trials with respiratory-related hospitalisation as an end-point. Experts reviewed the algorithm until a consensus was reached. The algorithm was validated using data from the phase 3 ISABELA trials (clinicaltrials.gov identifiers NCT03711162 and NCT03733444), by assessing concordance between nonadjudicated, investigator-defined, respiratory-related hospitalisations and those defined by the adjudication committee using the algorithm.

Results

The algorithm classifies respiratory-related hospitalisation according to cause: extraparenchymal (worsening respiratory symptoms due to left heart failure, volume overload, pulmonary embolism, pneumothorax or trauma); other (respiratory tract infection, right heart failure or exacerbation of COPD); "definite" acute exacerbation of IPF (AEIPF) (worsening respiratory symptoms within 1 month, with radiological or histological evidence of diffuse alveolar damage); or "suspected" AEIPF (as for "definite" AEIPF, but with no radiological or histological evidence of diffuse alveolar damage). Exacerbations ("definite" or "suspected") with identified triggers (infective, post-procedural or traumatic, drug toxicity- or aspiration-related) are classed as "known AEIPF"; "idiopathic AEIPF" refers to exacerbations with no identified trigger. In the ISABELA programme, there was 94% concordance between investigator- and adjudication committee-determined causes of respiratory-related hospitalisation.

Conclusion

The algorithm could help to ensure consistency in the reporting of respiratory-related hospitalisation in IPF trials, optimising its utility as an end-point.

Myositis-associated interstitial lung disease

PURPOSE OF REVIEW

In idiopathic inflammatory myopathies (IIMs), interstitial lung disease (ILD) is common and the autoantibody profile, made up of myositis-specific and myositis-associated (MSA and MAA) antibodies, can predict the clinical phenotype and progression over time. This review will focus on the characteristics and management of antisynthetase syndrome related ILD and anti-MDA5 positive ILD, which are the most clinically relevant subtypes.

RECENT FINDINGS

The prevalence of ILD in IIM has been estimated in Asia, North America and Europe at 50, 23 and 26%, respectively, and is increasing. In antisynthetase syndrome related ILD, the clinical presentation, progression and prognosis varies among anti-ARS antibodies. ILD is more common and severe in patients with anti-PL-7/anti-PL-12 antibodies when compared with anti Jo-1 patients. The prevalence of anti-MDA5 antibodies is higher in Asians (11-60%) than in whites (7-16%). Sixty-six percent of antisynthetase syndrome patients had 'chronic ILD' compared with the more rapidly progressive ILD (RP-ILD) seen in 69% of patients with anti-MDA5 antibodies.

SUMMARY

ILD is most common in the antisynthetase subtype of IIM and can be a chronic indolent or RP- ILD. The MSA and MAAs are associated with different clinical phenotypes of ILD. Treatments typically involve combinations of corticosteroids and other immunosuppressants.

The Genetic Landscape of Familial Pulmonary Fibrosis

Rationale and Objectives: Up to 20% of idiopathic interstitial lung disease is familial, referred to as familial pulmonary fibrosis (FPF). An integrated analysis of FPF genetic risk was performed by comprehensively evaluating for genetic rare variants (RVs) in a large cohort of FPF kindreds. Methods: Whole-exome sequencing and/or candidate gene sequencing from affected individuals in 569 FPF kindreds was performed, followed by cosegregation analysis in large kindreds, gene burden analysis, gene-based risk scoring, cell-type enrichment analysis, and coexpression network construction. Measurements and Main Results: It was found that 14.9-23.4% of genetic risk in kindreds could be explained by RVs in genes previously linked to FPF, predominantly telomere-related genes. New candidate genes were identified in a small number of families-including SYDE1, SERPINB8, GPR87, and NETO1-and tools were developed for evaluation and prioritization of RV-containing genes across kindreds. Several pathways were enriched for RV-containing genes in FPF, including focal adhesion and mitochondrial complex I assembly. By combining single-cell transcriptomics with prioritized candidate genes, expression of RV-containing genes was discovered to be enriched in smooth muscle cells, type II alveolar epithelial cells, and endothelial cells. Conclusions: In the most comprehensive FPF genetic study to date, the prevalence of RVs in known FPF-related genes was defined, and new candidate genes and pathways relevant to FPF were identified. However, new RV-containing genes shared across multiple kindreds were not identified, thereby suggesting that heterogeneous genetic variants involving a variety of genes and pathways mediate genetic risk in most FPF kindreds.

Ziritaxestat, a Novel Autotaxin Inhibitor, and Lung Function in Idiopathic Pulmonary Fibrosis: The ISABELA 1 and 2 Randomized Clinical Trials

Importance

There is a major need for effective, well-tolerated treatments for idiopathic pulmonary fibrosis (IPF).

Objective

To assess the efficacy and safety of the autotaxin inhibitor ziritaxestat in patients with IPF.

Design, Setting, and Participants

The 2 identically designed, phase 3, randomized clinical trials, ISABELA 1 and ISABELA 2, were conducted in Africa, Asia-Pacific region, Europe, Latin America, the Middle East, and North America (26 countries). A total of 1306 patients with IPF were randomized (525 patients at 106 sites in ISABELA 1 and 781 patients at 121 sites in ISABELA 2). Enrollment began in November 2018 in both trials and follow-up was completed early due to study termination on April 12, 2021, for ISABELA 1 and on March 30, 2021, for ISABELA 2.

Interventions

Patients were randomized 1:1:1 to receive 600 mg of oral ziritaxestat, 200 mg of ziritaxestat, or placebo once daily in addition to local standard of care (pirfenidone, nintedanib, or neither) for at least 52 weeks.

Main Outcomes and Measures

The primary outcome was the annual rate of decline for forced vital capacity (FVC) at week 52. The key secondary outcomes were disease progression, time to first respiratory-related hospitalization, and change from baseline in St George's Respiratory Questionnaire total score (range, 0 to 100; higher scores indicate poorer health-related quality of life).

Results

At the time of study termination, 525 patients were randomized in ISABELA 1 and 781 patients in ISABELA 2 (mean age: 70.0 [SD, 7.2] years in ISABELA 1 and 69.8 [SD, 7.1] years in ISABELA 2; male: 82.4% and 81.2%, respectively). The trials were terminated early after an independent data and safety monitoring committee concluded that the benefit to risk profile of ziritaxestat no longer supported their continuation. Ziritaxestat did not improve the annual rate of FVC decline vs placebo in either study. In ISABELA 1, the least-squares mean annual rate of FVC decline was -124.6 mL (95% CI, -178.0 to -71.2 mL) with 600 mg of ziritaxestat vs -147.3 mL (95% CI, -199.8 to -94.7 mL) with placebo (between-group difference, 22.7 mL [95% CI, -52.3 to 97.6 mL]), and -173.9 mL (95% CI, -225.7 to -122.2 mL) with 200 mg of ziritaxestat (between-group difference vs placebo, -26.7 mL [95% CI, -100.5 to 47.1 mL]). In ISABELA 2, the least-squares mean annual rate of FVC decline was -173.8 mL (95% CI, -209.2 to -138.4 mL) with 600 mg of ziritaxestat vs -176.6 mL (95% CI, -211.4 to -141.8 mL) with placebo (between-group difference, 2.8 mL [95% CI, -46.9 to 52.4 mL]) and -174.9 mL (95% CI, -209.5 to -140.2 mL) with 200 mg of ziritaxestat (between-group difference vs placebo, 1.7 mL [95% CI, -47.4 to 50.8 mL]). There was no benefit with ziritaxestat vs placebo for the key secondary outcomes. In ISABELA 1, all-cause mortality was 8.0% with 600 mg of ziritaxestat, 4.6% with 200 mg of ziritaxestat, and 6.3% with placebo; in ISABELA 2, it was 9.3% with 600 mg of ziritaxestat, 8.5% with 200 mg of ziritaxestat, and 4.7% with placebo.

Conclusions and Relevance

Ziritaxestat did not improve clinical outcomes compared with placebo in patients with IPF receiving standard of care treatment with pirfenidone or nintedanib or in those not receiving standard of care treatment.

Trial Registration

ClinicalTrials.gov Identifiers: NCT03711162 and NCT03733444.

Systemic sclerosis associated interstitial lung disease: a conceptual framework for subclinical, clinical and progressive disease

OBJECTIVES

To establish a framework by which experts define disease subsets in systemic sclerosis associated interstitial lung disease (SSc-ILD).

METHODS

A conceptual framework for subclinical, clinical and progressive ILD was provided to 83 experts, asking them to use the framework and classify actual SSc-ILD patients. Each patient profile was designed to be classified by at least four experts in terms of severity and risk of progression at baseline; progression was based on 1-year follow-up data. A consensus was reached if ≥75% of experts agreed. Experts provided information on which items were important in determining classification.

RESULTS

Forty-four experts (53%) completed the survey. Consensus was achieved on the dimensions of severity (75%, 60 of 80 profiles), risk of progression (71%, 57 of 80 profiles) and progressive ILD (60%, 24 of 40 profiles). For profiles achieving consensus, most were classified as clinical ILD (92%), low risk (54%) and stable (71%). Severity and disease progression overlapped in terms of framework items that were most influential in classifying patients (forced vital capacity, extent of lung involvement on high resolution chest CT [HRCT]); risk of progression was influenced primarily by disease duration.

CONCLUSIONS

Using our proposed conceptual framework, international experts were able to achieve a consensus on classifying SSc-ILD patients along the dimensions of disease severity, risk of progression and progression over time. Experts rely on similar items when classifying disease severity and progression: a combination of spirometry and gas exchange and quantitative HRCT.

Idiopathic Pulmonary Fibrosis Is Associated with Common Genetic Variants and Limited Rare Variants

Rationale: Idiopathic pulmonary fibrosis (IPF) is a rare, irreversible, and progressive disease of the lungs. Common genetic variants, in addition to nongenetic factors, have been consistently associated with IPF. Rare variants identified by candidate gene, family-based, and exome studies have also been reported to associate with IPF. However, the extent to which rare variants, genome-wide, may contribute to the risk of IPF remains unknown. Objectives: We used whole-genome sequencing to investigate the role of rare variants, genome-wide, on IPF risk. Methods: As part of the Trans-Omics for Precision Medicine Program, we sequenced 2,180 cases of IPF. Association testing focused on the aggregated effect of rare variants (minor allele frequency ⩽0.01) within genes or regions. We also identified individual rare variants that are influential within genes and estimated the heritability of IPF on the basis of rare and common variants. Measurements and Main Results: Rare variants in both TERT and RTEL1 were significantly associated with IPF. A single rare variant in each of the TERT and RTEL1 genes was found to consistently influence the aggregated test statistics. There was no significant evidence of association with other previously reported rare variants. The SNP heritability of IPF was estimated to be 32% (SE = 3%). Conclusions: Rare variants within the TERT and RTEL1 genes and well-established common variants have the largest contribution to IPF risk overall. Efforts in risk profiling or the development of therapies for IPF that focus on TERT, RTEL1, common variants, and environmental risk factors are likely to have the largest impact on this complex disease.

Incidence and Progression of Fibrotic Lung Disease in an At-Risk Cohort

Rationale: Relatives of patients with familial interstitial pneumonia (FIP) are at increased risk for pulmonary fibrosis and develop preclinical pulmonary fibrosis (PrePF). Objectives: We defined the incidence and progression of new-onset PrePF and its relationship to survival among first-degree relatives of families with FIP. Methods: This is a cohort study of family members with FIP who were initially screened with a health questionnaire and chest high-resolution computed tomography (HRCT) scan, and approximately 4 years later, the evaluation was repeated. A total of 493 asymptomatic first-degree relatives of patients with FIP were evaluated at baseline, and 296 (60%) of the original subjects participated in the subsequent evaluation. Measurements and Main Results: The median interval between HRCTs was 3.9 years (interquartile range, 3.5-4.4 yr). A total of 252 subjects who agreed to repeat evaluation were originally determined not to have PrePF at baseline; 16 developed PrePF. A conservative estimate of the annual incidence of PrePF is 1,023 per 100,000 person-years (95% confidence interval, 511-1,831 per 100,000 person-years). Of 44 subjects with PrePF at baseline, 38.4% subjects had worsening dyspnea compared with 15.4% of those without PrePF (P = 0.002). Usual interstitial pneumonia by HRCT (P < 0.0002) and baseline quantitative fibrosis score (P < 0.001) are also associated with worsening dyspnea. PrePF at the initial screen is associated with decreased survival (P < 0.001). Conclusions: The incidence of PrePF in this at-risk population is at least 100-fold higher than that reported for sporadic idiopathic pulmonary fibrosis (IPF). Although PrePF and IPF represent distinct entities, our study demonstrates that PrePF, like IPF, is progressive and associated with decreased survival.

Progressive pulmonary fibrosis: an expert group consensus statement

This expert group consensus statement emphasises the need for standardising the definition of progressive fibrosing interstitial lung diseases (F-ILDs), with an accurate initial diagnosis being of paramount importance in ensuring appropriate initial management. Equally, case-by-case decisions on monitoring and management are essential, given the varying presentations of F-ILDs and the varying rates of progression. The value of diagnostic tests in risk stratification at presentation and, separately, the importance of a logical monitoring strategy, tailored to manage the risk of progression, are also stressed. The term "progressive pulmonary fibrosis" (PPF) exactly describes the entity that clinicians often face in practice. The importance of using antifibrotic therapy early in PPF (once initial management has failed to prevent progression) is increasingly supported by evidence. Artificial intelligence software for high-resolution computed tomography analysis, although an exciting tool for the future, awaits validation. Guidance is provided on pulmonary rehabilitation, oxygen and the use of non-invasive ventilation focused specifically on the needs of ILD patients with progressive disease. PPF should be differentiated from acute deterioration due to drug-induced lung toxicity or other forms of acute exacerbations. Referral criteria for a lung transplant are discussed and applied to patient needs in severe diseases where transplantation is not realistic, either due to access limitations or transplantation contraindications. In conclusion, expert group consensus guidance is provided on the diagnosis, treatment and monitoring of F-ILDs with specific focus on the recognition of PPF and the management of pulmonary fibrosis progressing despite initial management.

Nintedanib in children and adolescents with fibrosing interstitial lung diseases

BACKGROUND

Childhood interstitial lung disease (ILD) comprises a spectrum of rare ILDs affecting infants, children and adolescents. Nintedanib is a licensed treatment for pulmonary fibrosis in adults. The primary objectives of the InPedILD trial were to determine the dose-exposure and safety of nintedanib in children and adolescents with fibrosing ILD.

METHODS

Patients aged 6-17 years with fibrosing ILD on high-resolution computed tomography and clinically significant disease were randomised 2:1 to receive nintedanib or placebo for 24 weeks and then open-label nintedanib. Dosing was based on weight-dependent allometric scaling. Co-primary end-points were the area under the plasma concentration-time curve at steady state (AUC_τ,ss) at weeks 2 and 26 and the proportion of patients with treatment-emergent adverse events at week 24.

RESULTS

26 patients received nintedanib and 13 patients received placebo. The geometric mean (geometric coefficient of variation) AUC_τ,ss for nintedanib was 175 µg·h·L^-1 (85.1%) in patients aged 6-11 years and 160 µg·h·L^-1 (82.7%) in patients aged 12-17 years. In the double-blind period, adverse events were reported in 84.6% of patients in each treatment group. Two patients discontinued nintedanib due to adverse events. Diarrhoea was reported in 38.5% and 15.4% of the nintedanib and placebo groups, respectively. Adjusted mean±se changes in percentage predicted forced vital capacity at week 24 were 0.3±1.3% in the nintedanib group and -0.9±1.8% in the placebo group.

CONCLUSIONS

In children and adolescents with fibrosing ILD, a weight-based dosing regimen resulted in exposure to nintedanib similar to adults and an acceptable safety profile. These data provide a scientific basis for the use of nintedanib in this patient population.

Nintedanib in Asian patients with progressive fibrosing interstitial lung diseases: Results from the INBUILD trial

BACKGROUND AND OBJECTIVE

In the INBUILD trial in patients with progressive fibrosing interstitial lung diseases (ILDs), nintedanib reduced the rate of decline in forced vital capacity (FVC) with an adverse event profile characterized mainly by gastrointestinal events. We analysed the effects of nintedanib in the subset of Asian subjects.

METHODS

Subjects with fibrosing ILDs other than idiopathic pulmonary fibrosis who had shown progression of ILD at any time within the prior 24 months despite management deemed appropriate in clinical practice were randomized to receive nintedanib or placebo. We analysed the rate of decline in FVC (ml/year) over 52 weeks in all Asian subjects and in Asian subjects with a usual interstitial pneumonia (UIP)-like fibrotic pattern on high-resolution computed tomography (HRCT).

RESULTS

One hundred sixty-four subjects in the INBUILD trial were of Asian race. The rate of decline in FVC (ml/year) over 52 weeks in this subgroup was -116.8 in the nintedanib group and -207.9 in the placebo group (difference: 91.0 [95% CI: 8.1, 173.9]; nominal p = 0.03). In Asian subjects with a UIP-like fibrotic pattern on HRCT, the rate of decline in FVC (ml/year) over 52 weeks was -130.1 in the nintedanib group and -224.2 in the placebo group (difference: 94.1 [5.5, 182.7]; nominal p = 0.04). Adverse events led to treatment discontinuation in 19.0% of the nintedanib group and 13.8% of the placebo group.

CONCLUSION

In Asian patients with progressive fibrosing ILDs, nintedanib reduced the rate of decline in FVC with adverse events that were manageable for most patients.

Colocalization of Gene Expression and DNA Methylation with Genetic Risk Variants Supports Functional Roles of MUC5B and DSP in Idiopathic Pulmonary Fibrosis

Rationale: Common genetic variants have been associated with idiopathic pulmonary fibrosis (IPF). Objectives: To determine functional relevance of the 10 IPF-associated common genetic variants we previously identified. Methods: We performed expression quantitative trait loci (eQTL) and methylation quantitative trait loci (mQTL) mapping, followed by co-localization of eQTL and mQTL with genetic association signals and functional validation by luciferase reporter assays. Illumina multi-ethnic genotyping arrays, mRNA sequencing, and Illumina 850k methylation arrays were performed on lung tissue of participants with IPF (234 RNA and 345 DNA samples) and non-diseased controls (188 RNA and 202 DNA samples). Measurements and Main Results: Focusing on genetic variants within 10 IPF-associated genetic loci, we identified 27 eQTLs in controls and 24 eQTLs in cases (false-discovery-rate-adjusted P < 0.05). Among these signals, we identified associations of lead variants rs35705950 with expression of MUC5B and rs2076295 with expression of DSP in both cases and controls. mQTL analysis identified CpGs in gene bodies of MUC5B (cg17589883) and DSP (cg08964675) associated with the lead variants in these two loci. We also demonstrated strong co-localization of eQTL/mQTL and genetic signal in MUC5B (rs35705950) and DSP (rs2076295). Functional validation of the mQTL in MUC5B using luciferase reporter assays demonstrates that the CpG resides within a putative internal repressor element. Conclusions: We have established a relationship of the common IPF genetic risk variants rs35705950 and rs2076295 with respective changes in MUC5B and DSP expression and methylation. These results provide additional evidence that both MUC5B and DSP are involved in the etiology of IPF.

Burden of illness in progressive fibrosing interstitial lung disease

BACKGROUND: Progressive fibrosing interstitial lung disease (ILD) is a relatively new clinical concept describing a variety of ILDs characterized by progressive pulmonary fibrosis with associated lung function decline and worsening chest imaging. Little is known about health care resource utilization (HCRU) and costs associated with progressive fibrosing ILDs other than idiopathic pulmonary fibrosis (IPF). This study analyzed the adjusted HCRU and cost burden among patients with incident non-IPF progressive fibrosing ILD vs matched patients with incident fibrosing ILD that had not yet progressed. METHODS: This was a retrospective study of insured US adults newly diagnosed with non-IPF fibrosing ILD from October 2016 to June 2019, conducted using administrative claims data from the Optum Research Database. Progressive disease was identified using claims-based proxies comprising health care utilization associated with management of progressive fibrosing ILD. Patients in the progressive population were 1:1 propensity score matched to not-yet-progressed patients on the basis of baseline demographic and clinical characteristics. All-cause HCRU and health care costs were presented as weighted per-patient-per-month (PPPM) measures to account for variable follow-up. Differences in study outcomes between matched cohorts were evaluated using Z-tests for continuous measures and Rao-Scott tests for binary measures. RESULTS: The postmatch cohorts comprised 11,025 patients with evidence of progression matched to 11,025 patients with not-yet-progressed fibrosing ILD. Mean (SD) weighted PPPM counts of follow-up health care encounters were significantly higher for the progressive vs not-yet-progressed cohort: ambulatory visits, 4.2 (3.6) vs 3.1 (3.3); emergency department visits, 0.3 (0.5) vs 0.1 (0.3); and inpatient (IP) stays, 0.1 (0.2) vs 0.0 (0.1) (P < 0.001 for all). Among patients with an IP stay, those with progressive disease had more inpatient days than those with not-yet-progressed disease (mean [SD] 1.6 [2.4] days vs 1.0 [1.3] days, P < 0.001). Mean weighted PPPM (SD) all-cause health care costs were also significantly higher for progressive vs not-yet-progressed patients, including total costs ($4,382 [$9,597] vs $2,243 [$4,162], P < 0.001), medical costs ($3,662 [$9,150] vs $1,627 [$3,524], P < 0.001), and pharmacy costs ($720 [$2,097] vs $616 [$2,070], P = 0.002). The difference in medical costs between cohorts was driven primarily by higher inpatient costs for progressive vs not-yet-progressed patients ($1,729 [$7,557] vs $523 [$2,118], P < 0.001). CONCLUSIONS: Progressive fibrosing ILD carries a substantial economic and health care burden. Among patients with incident non-IPF fibrosing ILD, all-cause HCRU and costs were significantly higher for those with a progressive phenotype than for matched patients whose disease had not yet progressed. The cost differential was driven primarily by hospitalizations, which were longer and more frequent for the progressive cohort. Disclosures: This work was funded by Boehringer Ingelheim Pharmaceuticals, Inc. Drs Conoscenti and Shetty are employees of Boehringer Ingelheim (BI). Dr Singer was an employee of BI at the time the study was conducted. Dr Brown was a paid consultant for BI for this study. Dr Bengtson, Ms Anderson, and Dr Brekke are employees of Optum, which was contracted by BI to conduct the study. Medical writing assistance was provided by Yvette Edmonds, PhD (Optum), and was contracted and funded by Boehringer Ingelheim Pharmaceuticals, Inc.

Algorithmic Approach to the Diagnosis of Organizing Pneumonia: A Correlation of Clinical, Radiologic, and Pathologic Features

Organizing pneumonia (OP), characterized histopathologically by patchy filling of alveoli and bronchioles by loose plugs of connective tissue, may be seen in a variety of conditions. These include but are not limited to after an infection, drug reactions, radiation therapy, and collagen vascular diseases. When a specific cause is responsible for this entity, it is referred to as "secondary OP." When an extensive search fails to reveal a cause, it is referred to as "cryptogenic OP" (previously called "bronchiolitis obliterans with OP"), which is a clinical, radiologic, and pathologic entity classified as an interstitial lung disease. The clinical presentation of OP often mimics that of other disorders, such as infection and cancer, which can result in a delay in diagnosis and inappropriate management of the underlying disease. The radiographic presentation of OP is polymorphous but often has subpleural consolidations with air bronchograms or solitary or multiple nodules, which can wax and wane. Diagnosis of OP sometimes requires histopathologic confirmation and exclusion of other possible causes. Treatment usually requires a prolonged steroid course, and disease relapse is common. The aim of this article is to summarize the clinical, radiographic, and histologic presentations of this disease and to provide a practical diagnostic algorithmic approach incorporating clinical history and characteristic imaging patterns.

Lung tissue shows divergent gene expression between chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis

BACKGROUND

Chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF) are characterized by shared exposures and clinical features, but distinct genetic and pathologic features exist. These features have not been well-studied using large-scale gene expression datasets. We hypothesized that there are divergent gene, pathway, and cellular signatures between COPD and IPF.

METHODS

We performed RNA-sequencing on lung tissues from individuals with IPF (n = 231) and COPD (n = 377) compared to control (n = 267), defined as individuals with normal spirometry. We grouped the overlapping differential expression gene sets based on direction of expression and examined the resultant sets for genes of interest, pathway enrichment, and cell composition. Using gene set variation analysis, we validated the overlap group gene sets in independent COPD and IPF data sets.

RESULTS

We found 5010 genes differentially expressed between COPD and control, and 11,454 genes differentially expressed between IPF and control (1% false discovery rate). 3846 genes overlapped between IPF and COPD. Several pathways were enriched for genes upregulated in COPD and downregulated in IPF; however, no pathways were enriched for genes downregulated in COPD and upregulated in IPF. There were many myeloid cell genes with increased expression in COPD but decreased in IPF. We found that the genes upregulated in COPD but downregulated in IPF were associated with lower lung function in the independent validation cohorts.

CONCLUSIONS

We identified a divergent gene expression signature between COPD and IPF, with increased expression in COPD and decreased in IPF. This signature is associated with worse lung function in both COPD and IPF.

Integrating Clinical Probability into the Diagnostic Approach to Idiopathic Pulmonary Fibrosis: An International Working Group Perspective

BACKGROUND

When considering the diagnosis of idiopathic pulmonary fibrosis (IPF), experienced clinicians integrate clinical features that help to differentiate IPF from other fibrosing interstitial lung diseases, thus generating a "pre-test" probability of IPF. The aim of this international working group perspective was to summarize these features using a tabulated approach similar to chest HRCT and histopathologic patterns reported in the international guidelines for the diagnosis of IPF, and to help formally incorporate these clinical likelihoods into diagnostic reasoning to facilitate the diagnosis of IPF.

METHODS

The committee group identified factors that influence the clinical likelihood of a diagnosis of IPF, which was categorized as a pre-test clinical probability of IPF into "high" (70-100%), "intermediate" (30-70%), or "low" (0-30%). After integration of radiological and histopathological features, the post-test probability of diagnosis was categorized into "definite" (90-100%), "high confidence" (70-89%), "low confidence" (51-69%), or "low" (0-50%) probability of IPF.

FINDINGS

A conceptual Bayesian framework was created, integrating the clinical likelihood of IPF ("pre-test probability of IPF") with the HRCT pattern, the histopathology pattern when available, and/or the pattern of observed disease behavior into a "post-test probability of IPF". The diagnostic probability of IPF was expressed using an adapted diagnostic ontology for fibrotic interstitial lung diseases.

INTERPRETATION

The present approach will help incorporate the clinical judgement into the diagnosis of IPF, thus facilitating the application of IPF diagnostic guidelines and, ultimately improving diagnostic confidence and reducing the need for invasive diagnostic techniques.

Prevalence and prognosis of chronic fibrosing interstitial lung diseases with a progressive phenotype

BACKGROUND AND OBJECTIVE

The development of clinically progressive fibrosis complicates a wide array of interstitial lung diseases (ILDs). However, there are limited data regarding its prevalence and prognosis.

METHODS

We analysed consecutive patients seen for initial evaluation of a fibrosing form of ILD (FILD). Patients were evaluated for evidence of progressive fibrosis over the first 24 months of follow-up. We defined a progressive phenotype as the presence of at least one of the following: a relative decline in forced vital capacity (FVC) of ≥10%; a relative decline in FVC of ≥5%-<10% with a relative decline in diffusing capacity of the lung for carbon monoxide of ≥15%, increased fibrosis on HRCT or progressive symptoms.

RESULTS

Eight hundred and forty-four patients (397 with idiopathic pulmonary fibrosis [IPF] and 447 non-IPF FILD) made up the final analysis cohort. Three hundred and fifty-five patients (42.1%) met the progressive phenotype criteria (59.4% of IPF patients and 26.6% of non-IPF FILD patients, p <0.01). In both IPF and non-IPF FILD, transplantation-free survival differed between patients with a progressive phenotype and those without (p <0.01). Multivariable analysis showed that a progressive phenotype was an independent predictor of transplantation-free survival (hazard ratio [HR]: 3.36, 95% CI: 2.68-4.23, p <0.01). Transplantation-free survival did not differ between non-IPF FILD with a progressive phenotype and IPF (HR: 1.12, 95% CI: 0.85-1.48, p = 0.42).

CONCLUSION

Over one-fourth of non-IPF FILD patients develop a progressive phenotype compared to approximately 60% of IPF patients. The survival of non-IPF FILD patients with a progressive phenotype is similar to IPF.

Predictors of mortality in subjects with progressive fibrosing interstitial lung diseases

Background and objective

Demographic and clinical variables, measured at baseline or over time, have been associated with mortality in subjects with progressive fibrosing interstitial lung diseases (ILDs). We used data from the INPULSIS trials in subjects with idiopathic pulmonary fibrosis (IPF) and the INBUILD trial in subjects with other progressive fibrosing ILDs to assess relationships between demographic/clinical variables and mortality.

Methods

The relationships between baseline variables and time‐varying covariates and time to death over 52 weeks were analysed using pooled data from the INPULSIS trials and, separately, the INBUILD trial using a Cox proportional hazards model.

Results

Over 52 weeks, 68/1061 (6.4%) and 33/663 (5.0%) subjects died in the INPULSIS and INBUILD trials, respectively. In the INPULSIS trials, a relative decline in forced vital capacity (FVC) >10% predicted within 12 months (hazard ratio [HR] 3.77) and age (HR 1.03 per 1‐year increase) were associated with increased risk of mortality, while baseline FVC % predicted (HR 0.97 per 1‐unit increase) and diffusing capacity of the lungs for carbon monoxide (DLCO) % predicted (HR 0.77 per 1‐unit increase) were associated with lower risk. In the INBUILD trial, a relative decline in FVC >10% predicted within 12 months (HR 2.60) and a usual interstitial pneumonia‐like fibrotic pattern on HRCT (HR 2.98) were associated with increased risk of mortality, while baseline DLCO % predicted (HR 0.95 per 1‐unit increase) was associated with lower risk.

Conclusion

These data support similarity in the course of lung injury between IPF and other progressive fibrosing ILDs and the value of FVC decline as a predictor of mortality.

We assessed relationships between baseline and time‐varying factors and mortality over 52 weeks in 1061 subjects with idiopathic pulmonary fibrosis (IPF) and 663 subjects with other progressive fibrosing interstitial lung diseases (ILDs). Our findings support similarity in the course of IPF and ILD and an association between decline in forced vital capacity and mortality.

Alpha-1 Antitrypsin MZ Heterozygosity Is an Endotype of Chronic Obstructive Pulmonary Disease

Rationale: Multiple studies have demonstrated an increased risk of chronic obstructive pulmonary disease (COPD) in heterozygous carriers of the AAT (alpha-1 antitrypsin) Z allele. However, it is not known if MZ subjects with COPD are phenotypically different from noncarriers (MM genotype) with COPD. Objectives: To assess if MZ subjects with COPD have different clinical features compared with MM subjects with COPD. Methods: Genotypes of SERPINA1 were ascertained by using whole-genome sequencing data in three independent studies. We compared outcomes between MM subjects with COPD and MZ subjects with COPD in each study and combined the results in a meta-analysis. We performed longitudinal and survival analyses to compare outcomes in MM and MZ subjects with COPD over time. Measurements and Main Results: We included 290 MZ subjects with COPD and 6,184 MM subjects with COPD across the three studies. MZ subjects had a lower FEV₁% predicted and greater quantitative emphysema on chest computed tomography scans compared with MM subjects. In a meta-analysis, the FEV₁ was 3.9% lower (95% confidence interval [CI], -6.55% to -1.26%) and emphysema (the percentage of lung attenuation areas <-950 HU) was 4.14% greater (95% CI, 1.44% to 6.84%) in MZ subjects. We found one gene, PGF (placental growth factor), to be differentially expressed in lung tissue from one study between MZ subjects and MM subjects. Conclusions: Carriers of the AAT Z allele (those who were MZ heterozygous) with COPD had lower lung function and more emphysema than MM subjects with COPD. Taken with the subtle differences in gene expression between the two groups, our findings suggest that MZ subjects represent an endotype of COPD.

Diagnosis and monitoring of systemic sclerosis-associated interstitial lung disease using high-resolution computed tomography

Patients with systemic sclerosis are at high risk of developing systemic sclerosis–associated interstitial lung disease. Symptoms and outcomes of systemic sclerosis–associated interstitial lung disease range from subclinical lung involvement to respiratory failure and death. Early and accurate diagnosis of systemic sclerosis–associated interstitial lung disease is therefore important to enable appropriate intervention. The most sensitive and specific way to diagnose systemic sclerosis–associated interstitial lung disease is by high-resolution computed tomography, and experts recommend that high-resolution computed tomography should be performed in all patients with systemic sclerosis at the time of initial diagnosis. In addition to being an important screening and diagnostic tool, high-resolution computed tomography can be used to evaluate disease extent in systemic sclerosis–associated interstitial lung disease and may be helpful in assessing prognosis in some patients. Currently, there is no consensus with regards to frequency and scanning intervals in patients at risk of interstitial lung disease development and/or progression. However, expert guidance does suggest that frequency of screening using high-resolution computed tomography should be guided by risk of developing interstitial lung disease. Most experienced clinicians would not repeat high-resolution computed tomography more than once a year or every other year for the first few years unless symptoms arose. Several computed tomography techniques have been developed in recent years that are suitable for regular monitoring, including low-radiation protocols, which, together with other technologies, such as lung ultrasound and magnetic resonance imaging, may further assist in the evaluation and monitoring of patients with systemic sclerosis–associated interstitial lung disease. A video abstract to accompany this article is available at: https://www.globalmedcomms.com/respiratory/Khanna/HRCTinSScILD

Outcome measurement instrument selection for lung physiology in systemic sclerosis associated interstitial lung disease: A systematic review using the OMERACT filter 2.1 process

OBJECTIVE

The Outcome Measures in Rheumatology (OMERACT) is a research organization focused on improving health care outcomes for patients with autoimmune and musculoskeletal diseases. The Connective Tissue Disease-Interstitial Lung Disease (CTD-ILD) Working Group on Lung Physiology is a group within OMERACT charged with identifying outcome measures that should be implemented in studies of patients with CTD-ILD. The OMERACT Filter 2.1 is an evidence-based algorithm used to identify outcome measures that are truthful, feasible, and able to discriminate between groups of interest. Our objective was to summate evidence (published literature, key opinion leader input, patient perspectives) that would influence the CTD-ILD Working Group's vote to accept or reject the use of two measures of lung physiology, the forced vital capacity (FVC) and the diffusion capacity of carbon monoxide (DLco) for use in randomized controlled trials (RTCs) and longitudinal observational studies (LOSs) involving patients with systemic sclerosis associated ILD (SSc-ILD).

METHODS

Patient Research Partners (those afflicted with SSc-ILD) and the CTD-ILD Working Group on Lung Physiology were polled to assess their opinion on the FVC and DLco in terms of feasibility; the CTD-ILD Working Group was also queried on these instruments' face and content validity. We then conducted a systematic literature review to identify articles in the SSc-ILD population that assessed the following measurement properties of FVC and DLco: (1) construct validity, (2) test-retest reliability, (3) longitudinal construct validity, (4) clinical trial discrimination/sensitivity to detect change in clinical trials, and (5) thresholds of meaning. Results were summarized in a Summary of Measurement Properties (SOMP) table for each instrument. OMERACT CTD-ILD Working Group members discussed and voted on the strength of evidence supporting these two instruments and voted to endorse, provisionally endorse, or not endorse either instrument.

RESULTS

Forty Patient Research Partners reported these two measures are feasible (are not an unnecessary burden or represent an infeasible longitudinal assessment of their disease). A majority of the 18 CTD-ILD Working Group members voted that both the FVC and DLco are feasible and have face and content validity. The systematic literature review returned 1,447 non-duplicated articles, of which 177 met eligibility for full text review. Forty-eight studies (13 RCTs, 35 LOSs) were included in the qualitative analysis. The FVC SOMP table revealed high quality, consistent data with evidence of good performance for all five measurement properties, suggesting requisite published evidence to proceed with endorsement. The DLco SOMP table showed a lack of data to support test-retest reliability and inadequate evidence to support clinical trial discrimination. There was unanimous agreement (15 [100%]) among voting CTD-ILD Working Group members to endorse the FVC as an instrument for lung physiology in RCTs and LOSs in SSc-ILD. Based on currently available evidence, DLco did not meet the OMERACT criteria and is not recommended for use in RCTs to represent lung physiology of SSc-ILD. The OMERACT Technical Advisory Group agreed with these decisions.

CONCLUSION

The OMERACT Filter 2.1 was successfully applied to the domain of lung physiology in patients with SSc-ILD. The FVC was endorsed for use in RCTs and LOSs based on the Working Group's vote; DLco was not endorsed.

The emerging role of mycophenolate mofetil in interstitial lung diseases

INTRODUCTION

Mycophenolate mofetil (MMF), initially approved to prevent rejection in solid organ allograft, is now being increasingly used for other conditions. Over the last decade, MMF has emerged as a useful therapy for a variety of immune-mediated diseases.

AREAS COVERED

There has been a growing interest in the clinical use of MMF in the treatment of ILDs due to its versatile anti-inflammatory, immunomodulatory, anti-fibrotic and anti-proliferative properties. In this focussed review, we summarize the available literature using the Pubmed, Science Direct and EMBASE databases published until June 2021 on the efficacy and tolerability of MMF in various ILDs.

EXPERT OPINION

Other than idiopathic pulmonary fibrosis (IPF) and its broader category of progressive fibrosing ILD, there have been no drugs approved by relevant regulatory agencies for the treatment of the multiple other forms of ILD. Though results are limited, immunosuppressants such as MMF have shown promise as an effective and well-tolerated steroid-sparing agent, providing hope that the limited treatment armamentarium for ILDs can be expanded.

Nintedanib in progressive interstitial lung diseases: data from the whole INBUILD trial

Background

The primary analysis of the INBUILD trial showed that in subjects with progressive fibrosing interstitial lung diseases (ILDs), nintedanib slowed the decline in forced vital capacity (FVC) over 52 weeks. We report the effects of nintedanib on ILD progression over the whole trial.

Methods

Subjects with fibrosing ILDs other than idiopathic pulmonary fibrosis, who had ILD progression within the 24 months before screening despite management deemed appropriate in clinical practice, were randomised to receive nintedanib or placebo. Subjects continued on blinded randomised treatment until all subjects had completed the trial. Over the whole trial, mean±sd exposure to trial medication was 15.6±7.2 and 16.8±5.8 months in the nintedanib and placebo groups, respectively.

Results

In the nintedanib (n=332) and placebo (n=331) groups, respectively, the proportions of subjects who had ILD progression (absolute decline in FVC ≥10% predicted) or died were 40.4% and 54.7% in the overall population (hazard ratio (HR) 0.66, 95% CI 0.53–0.83; p=0.0003) and 43.7% and 55.8% among subjects with a usual interstitial pneumonia (UIP)-like fibrotic pattern on high-resolution computed tomography (HRCT) (HR 0.69, 95% CI 0.53–0.91; p=0.009). In the nintedanib and placebo groups, respectively, the proportions who had an acute exacerbation of ILD or died were 13.9% and 19.6% in the overall population (HR 0.67, 95% CI 0.46–0.98; p=0.04) and 15.0% and 22.8% among subjects with a UIP-like fibrotic pattern on HRCT (HR 0.62, 95% CI 0.39–0.97; p=0.03).

Conclusion

Based on data from the whole INBUILD trial, nintedanib reduced the risk of events indicating ILD progression.

In patients with fibrosing ILDs other than IPF who had shown progression of ILD within the prior 2 years, events indicating further progression occurred frequently. Over a 16-month period, nintedanib reduced the risk of such events versus placebo.https://bit.ly/3yiZXnS

Effects of nintedanib by inclusion criteria for progression of interstitial lung disease

Background

The INBUILD trial investigated nintedanib versus placebo in patients with progressive fibrosing interstitial lung diseases (ILDs). We investigated the decline in forced vital capacity (FVC) in subgroups based on the inclusion criteria for ILD progression.

Methods

Subjects had a fibrosing ILD other than idiopathic pulmonary fibrosis and met the following criteria for ILD progression within the 24 months before screening despite management deemed appropriate in clinical practice: Group A, relative decline in FVC ≥10% predicted; Group B, relative decline in FVC ≥5–<10% predicted with worsened respiratory symptoms and/or increased extent of fibrosis on high-resolution computed tomography (HRCT); Group C, worsened respiratory symptoms and increased extent of fibrosis on HRCT only.

Results

In the placebo group, the rates of FVC decline over 52 weeks in Groups A, B and C, respectively, were −241.9, −133.1 and −115.3 mL per year in the overall population (p=0.0002 for subgroup-by-time interaction) and −288.9, −156.2 and −100.1 mL per year among subjects with a usual interstitial pneumonia (UIP)-like fibrotic pattern on HRCT (p=0.0005 for subgroup-by-time interaction). Nintedanib had a greater absolute effect on reducing the rate of FVC decline in Group A than in Group B or C. However, the relative effect of nintedanib versus placebo was consistent across the subgroups (p>0.05 for heterogeneity).

Conclusions

The inclusion criteria used in the INBUILD trial, based on FVC decline or worsening of symptoms and extent of fibrosis on HRCT, were effective at identifying patients with progressive fibrosing ILDs. Nintedanib reduced the rate of decline in FVC across the subgroups based on the inclusion criteria related to ILD progression.

In the INBUILD trial in patients with fibrosing ILDs, the relative effect of nintedanib versus placebo on reducing the rate of FVC decline was consistent across subgroups based on the criteria regarding ILD progression that patients fulfilled on trial entryhttps://bit.ly/35jpOiE

Study design of a randomised, placebo-controlled trial of nintedanib in children and adolescents with fibrosing interstitial lung disease

Childhood interstitial lung disease (chILD) comprises >200 rare respiratory disorders, with no currently approved therapies and variable prognosis. Nintedanib reduces the rate of forced vital capacity (FVC) decline in adults with progressive fibrosing interstitial lung diseases (ILDs). We present the design of a multicentre, prospective, double-blind, randomised, placebo-controlled clinical trial of nintedanib in patients with fibrosing chILD (1199-0337 or InPedILD; ClinicalTrials.gov: NCT04093024).

Male or female children and adolescents aged 6–17 years (≥30; including ≥20 adolescents aged 12–17 years) with clinically significant fibrosing ILD will be randomised 2:1 to receive oral nintedanib or placebo on top of standard of care for 24 weeks (double-blind), followed by variable-duration nintedanib (open-label). Nintedanib dosing will be based on body weight-dependent allometric scaling, with single-step dose reductions permitted to manage adverse events. Eligible patients will have evidence of fibrosis on high-resolution computed tomography (within 12 months of their first screening visit), FVC ≥25% predicted, and clinically significant disease (Fan score of ≥3 or evidence of clinical progression over time). Patients with underlying chronic liver disease, significant pulmonary arterial hypertension, cardiovascular disease, or increased bleeding risk are ineligible. The primary endpoints are pharmacokinetics and the proportion of patients with treatment-emergent adverse events at week 24. Secondary endpoints include change in FVC% predicted from baseline, Pediatric Quality of Life Questionnaire, oxygen saturation, and 6-min walk distance at weeks 24 and 52. Additional efficacy and safety endpoints will be collected to explore long-term effects.

We describe the design of #InPedILD, a study of 24 weeks’ nintedanib or placebo on top of standard of care, followed by variable-duration open-label nintedanib in children with interstitial lung disease (ClinicalTrials.gov NCT04093024) #PedILDhttps://bit.ly/3tC1a7P

Diagnosis and Evaluation of Hypersensitivity Pneumonitis: CHEST Guideline and Expert Panel Report

BACKGROUND

The purpose of this analysis is to provide evidence-based and consensus-derived guidance for clinicians to improve individual diagnostic decision-making for hypersensitivity pneumonitis (HP) and decrease diagnostic practice variability.

STUDY DESIGN AND METHODS

Approved panelists developed key questions regarding the diagnosis of HP using the PICO (Population, Intervention, Comparator, Outcome) format. MEDLINE (via PubMed) and the Cochrane Library were systematically searched for relevant literature, which was supplemented by manual searches. References were screened for inclusion, and vetted evaluation tools were used to assess the quality of included studies, to extract data, and to grade the level of evidence supporting each recommendation or statement. The quality of the evidence was assessed using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach. Graded recommendations and ungraded consensus-based statements were drafted and voted on using a modified Delphi technique to achieve consensus. A diagnostic algorithm is provided, using supporting data from the recommendations where possible, along with expert consensus to help physicians gauge the probability of HP.

RESULTS

The systematic review of the literature based on 14 PICO questions resulted in 14 key action statements: 12 evidence-based, graded recommendations and 2 ungraded consensus-based statements. All evidence was of very low quality.

INTERPRETATION

Diagnosis of HP should employ a patient-centered approach and include a multidisciplinary assessment that incorporates the environmental and occupational exposure history and CT pattern to establish diagnostic confidence prior to considering BAL and/or lung biopsy. Criteria are presented to facilitate diagnosis of HP. Additional research is needed on the performance characteristics and generalizability of exposure assessment tools and traditional and new diagnostic tests in modifying clinical decision-making for HP, particularly among those with a provisional diagnosis.

Executive Summary: Diagnosis and Evaluation of Hypersensitivity Pneumonitis: CHEST Guideline and Expert Panel Report

BACKGROUND

The purpose of this summary is to provide a synopsis of evidence-based and consensus-derived guidance for clinicians to improve individual diagnostic decision-making for hypersensitivity pneumonitis (HP) and decrease diagnostic practice variability.

STUDY DESIGN AND METHODS

Approved panelists developed key questions regarding the diagnosis of HP using the PICO (Population, Intervention, Comparator, and Outcome) format. MEDLINE (via PubMed) and the Cochrane Library were systematically searched for relevant literature, which was supplemented by manual searches. References were screened for inclusion and vetted evaluation tools were used to assess the quality of included studies, to extract data, and to grade the level of evidence supporting each recommendation or statement. The quality of the evidence was assessed using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach. Graded recommendations and ungraded consensus-based statements were drafted and voted on using a modified Delphi technique to achieve consensus.

RESULTS

The systematic review of the literature based on 14 PICO questions resulted in 14 key action statements: 12 evidence-based, graded recommendations, and 2 ungraded consensus-based statements. All evidence was of very low quality.

INTERPRETATION

Diagnosis of HP should employ a patient-centered approach and include a multidisciplinary assessment that incorporates the environmental and occupational exposure history and CT pattern to establish diagnostic confidence prior to considering BAL and/or lung biopsy. Additional research is needed on the performance characteristics and generalizability of exposure assessment tools and traditional and new diagnostic tests in modifying clinical decision-making for HP, particularly among those with a provisional diagnosis.

Chest CT Diagnosis and Clinical Management of Drug-related Pneumonitis in Patients Receiving Molecular Targeting Agents and Immune Checkpoint Inhibitors: A Position Paper from the Fleischner Society

Use of molecular targeting agents and immune checkpoint inhibitors (ICIs) has increased the frequency and broadened the spectrum of lung toxicity, particularly in patients with cancer. The diagnosis of drug-related pneumonitis (DRP) is usually achieved by excluding other potential known causes. Awareness of the incidence and risk factors for DRP is becoming increasingly important. The severity of symptoms associated with DRP may range from mild or none to life-threatening with rapid progression to death. Imaging features of DRP should be assessed in consideration of the distribution of lung parenchymal abnormalities (radiologic pattern approach). The CT patterns reflect acute (diffuse alveolar damage) interstitial pneumonia and transient (simple pulmonary eosinophilia) lung abnormality, subacute interstitial disease (organizing pneumonia and hypersensitivity pneumonitis), and chronic interstitial disease (nonspecific interstitial pneumonia). A single drug can be associated with multiple radiologic patterns. Treatment of a patient suspected of having DRP generally consists of drug discontinuation, immunosuppressive therapy, or both, along with supportive measures eventually including supplemental oxygen and intensive care. In this position paper, the authors provide diagnostic criteria and management recommendations for DRP that should be of interest to radiologists, clinicians, clinical trialists, and trial sponsors, among others. This article is a simultaneous joint publication in Radiology and CHEST. The articles are identical except for stylistic changes in keeping with each journal's style. Either version may be used in citing this article. Published under a CC BY 4.0 license. Online supplemental material is available for this article.

Chest CT Diagnosis and Clinical Management of Drug-Related Pneumonitis in Patients Receiving Molecular Targeting Agents and Immune Checkpoint Inhibitors: A Position Paper From the Fleischner Society

Use of molecular targeting agents and immune checkpoint inhibitors (ICIs) has increased the frequency and broadened the spectrum of lung toxicity, particularly in patients with cancer. The diagnosis of drug-related pneumonitis (DRP) is usually achieved by excluding other potential known causes. Awareness of the incidence and risk factors for DRP is becoming increasingly important. The severity of symptoms associated with DRP may range from mild or none to life-threatening with rapid progression to death. Imaging features of DRP should be assessed in consideration of the distribution of lung parenchymal abnormalities (radiologic pattern approach). The CT patterns reflect acute (diffuse alveolar damage) interstitial pneumonia and transient (simple pulmonary eosinophilia) lung abnormality, subacute interstitial disease (organizing pneumonia and hypersensitivity pneumonitis), and chronic interstitial disease (nonspecific interstitial pneumonia). A single drug can be associated with multiple radiologic patterns. Treatment of a patient suspected of having DRP generally consists of drug discontinuation, immunosuppressive therapy, or both, along with supportive measures eventually including supplemental oxygen and intensive care. In this position paper, the authors provide diagnostic criteria and management recommendations for DRP that should be of interest to radiologists, clinicians, clinical trialists, and trial sponsors, among others.

Reply to comment on "The natural history of progressive fibrosing interstitial lung diseases"

We thank Y.P. Moodley and co-workers for their thoughtful letter in response to our manuscript on the natural history of progressive fibrosing interstitial lung diseases (ILDs) [1]. We agree that early identification of patients with progression of their ILD is important to enable prompt implementation of appropriate treatment. The inclusion criteria for the INBUILD trial reflected current approaches used to identify patients with progressive ILD. However, we acknowledge that the pattern of progression of ILD varies among individual patients, and no single set of criteria will capture all of them.

No set of criteria will cover all patients, but the inclusion criteria used in the INBUILD trial were effective at identifying a population of patients with progressive ILDhttps://bit.ly/3mKkzzi

Chronic Hypersensitivity Pneumonitis, an Interstitial Lung Disease with Distinct Molecular Signatures

Rationale: Chronic hypersensitivity pneumonitis (CHP) is caused by an immune response to antigen inhalation and is characterized by variable histopathological and clinical features. A subset of subjects with CHP have usual interstitial pneumonia and appear to be clinically similar to subjects with idiopathic pulmonary fibrosis (IPF).Objectives: To determine the common and unique molecular features of CHP and IPF.Methods: Transcriptome analysis of lung samples from CHP (n = 82), IPF (n = 103), and unaffected controls (n = 103) was conducted. Differential gene expression was determined adjusting for sex, race, age, and smoking history and using false discovery rate to control for multiple comparisons.Measurements and Main Results: When compared with controls, we identified 413 upregulated and 317 downregulated genes in CHP and 861 upregulated and 322 downregulated genes in IPF. Concordantly upregulated or downregulated genes in CHP and IPF were related to collagen catabolic processes and epithelial development, whereas genes specific to CHP (differentially expressed in CHP when compared with control and not differentially expressed in IPF) were related to chemokine-mediated signaling and immune responsiveness. Using weighted gene coexpression network analysis, we found that among subjects with CHP, genes involved in adaptive immunity or epithelial cell development were associated with improved or reduced lung function, respectively, and that MUC5B expression was associated with epithelial cell development. MUC5B expression was also associated with lung fibrosis and honeycombing.Conclusions: Gene expression analysis of CHP and IPF identified signatures common to CHP and IPF, as well as genes uniquely expressed in CHP. Select modules of gene expression are characterized by distinct clinical and pathological features of CHP.

Interstitial lung abnormalities detected incidentally on CT: a Position Paper from the Fleischner Society

The term interstitial lung abnormalities refers to specific CT findings that are potentially compatible with interstitial lung disease in patients without clinical suspicion of the disease. Interstitial lung abnormalities are increasingly recognised as a common feature on CT of the lung in older individuals, occurring in 4-9% of smokers and 2-7% of non-smokers. Identification of interstitial lung abnormalities will increase with implementation of lung cancer screening, along with increased use of CT for other diagnostic purposes. These abnormalities are associated with radiological progression, increased mortality, and the risk of complications from medical interventions, such as chemotherapy and surgery. Management requires distinguishing interstitial lung abnormalities that represent clinically significant interstitial lung disease from those that are subclinical. In particular, it is important to identify the subpleural fibrotic subtype, which is more likely to progress and to be associated with mortality. This multidisciplinary Position Paper by the Fleischner Society addresses important issues regarding interstitial lung abnormalities, including standardisation of the definition and terminology; predisposing risk factors; clinical outcomes; options for initial evaluation, monitoring, and management; the role of quantitative evaluation; and future research needs.

The natural history of progressive fibrosing interstitial lung diseases

We used data from the INBUILD and INPULSIS trials to investigate the natural history of progressive fibrosing interstitial lung diseases (ILDs).

Subjects in the two INPULSIS trials had a clinical diagnosis of idiopathic pulmonary fibrosis (IPF) while subjects in the INBUILD trial had a progressive fibrosing ILD other than IPF and met protocol-defined criteria for ILD progression despite management. Using data from the placebo groups, we compared the rate of decline in forced vital capacity (FVC) (mL·year⁻¹) and mortality over 52 weeks in the INBUILD trial with pooled data from the INPULSIS trials.

The adjusted mean annual rate of decline in FVC in the INBUILD trial (n=331) was similar to that observed in the INPULSIS trials (n=423) (−192.9 mL·year⁻¹ and −221.0 mL·year⁻¹, respectively; nominal p-value=0.19). The proportion of subjects who had a relative decline in FVC >10% predicted at Week 52 was 48.9% in the INBUILD trial and 48.7% in the INPULSIS trials, and the proportion who died over 52 weeks was 5.1% in the INBUILD trial and 7.8% in the INPULSIS trials. A relative decline in FVC >10% predicted was associated with an increased risk of death in the INBUILD trial (hazard ratio 3.64) and the INPULSIS trials (hazard ratio 3.95).

These findings indicate that patients with fibrosing ILDs other than IPF, who are progressing despite management, have a subsequent clinical course similar to patients with untreated IPF, with a high risk of further ILD progression and early mortality.

Analyses of data from the INBUILD and INPULSIS trials suggest that progressive fibrosing ILDs other than IPF have a clinical course similar to IPF, irrespective of underlying ILD diagnosis or the fibrotic pattern on HRCThttp://bit.ly/3apG0Q5

Clinical Decision-Making in Hypersensitivity Pneumonitis: Diagnosis and Management

This review provides an updated approach to the diagnosis and management of hypersensitivity pneumonitis (HP). The importance of using a multidisciplinary discussion to increase diagnostic and treatment confidence is emphasized. The role of Bayesian reasoning is highlighted throughout, underscoring the importance of hypothesis generation (differential diagnosis) and diagnostic test interpretation based on the probability of HP. Probability estimates of diagnostic certainty (i.e., a confident versus a working diagnosis) and treatment thresholds are carefully examined.Therapeutically, beyond antigen avoidance and newly available antifibrotic therapy for patients with a progressive fibrosing phenotype; the role, timing, and expected response to anti-inflammatory therapy in individual patients are unanswered questions. Since the evidence and validation of testing generally performed during the diagnostic work-up and longitudinal monitoring of HP is feeble at best, the viewpoints discussed are not intended to resolve current controversies but rather to provide a conceptual framework for evaluating discordant information when evaluating and caring for patients with HP.

Probable usual interstitial pneumonia pattern on chest CT: is it sufficient for a diagnosis of idiopathic pulmonary fibrosis?

Recent studies have suggested that in patients with an idiopathic interstitial pneumonia (IIP), a probable usual interstitial pneumonia (UIP) pattern on chest computed tomography (CT) is sufficient to diagnose idiopathic pulmonary fibrosis (IPF) without histopathology.We retrospectively compared the prognosis and time to first acute exacerbation (AE) in IIP patients with a UIP and a probable UIP pattern on initial chest CT.One hundred and sixty IIP patients with a UIP pattern and 242 with a probable UIP pattern were identified. Probable UIP pattern was independently associated with longer survival time (adjusted hazard ratio 0.713, 95% CI 0.536-0.950; p=0.021) and time to first AE (adjusted hazard ratio 0.580, 95% CI 0.389-0.866; p=0.008). In subjects with a probable UIP pattern who underwent surgical lung biopsy, the probability of a histopathological UIP pattern was 83%. After multidisciplinary discussion and the inclusion of longitudinal behaviour, a diagnosis of IPF was made in 66% of cases. In IPF patients, survival time and time to first AE were not associated with CT pattern. Among subjects with a probable UIP pattern, compared to non-IPF patients, survival time and time to first AE were shorter in IPF patients.In conclusion, IIP patients with a probable UIP pattern on initial chest CT had a better prognosis and longer time to first AE than those with a UIP pattern. However, when baseline data and longitudinal behaviour provided a final diagnosis of IPF, CT pattern was not associated with these outcomes. This suggests diagnostic heterogeneity among patients with a probable UIP pattern.

Nintedanib in patients with progressive fibrosing interstitial lung diseases-subgroup analyses by interstitial lung disease diagnosis in the INBUILD trial: a randomised, double-blind, placebo-controlled, parallel-group trial

BACKGROUND

The INBUILD trial investigated the efficacy and safety of nintedanib versus placebo in patients with progressive fibrosing interstitial lung diseases (ILDs) other than idiopathic pulmonary fibrosis (IPF). We aimed to establish the effects of nintedanib in subgroups based on ILD diagnosis.

METHODS

The INBUILD trial was a randomised, double-blind, placebo-controlled, parallel group trial done at 153 sites in 15 countries. Participants had an investigator-diagnosed fibrosing ILD other than IPF, with chest imaging features of fibrosis of more than 10% extent on high resolution CT (HRCT), forced vital capacity (FVC) of 45% or more predicted, and diffusing capacity of the lung for carbon monoxide (DLco) of at least 30% and less than 80% predicted. Participants fulfilled protocol-defined criteria for ILD progression in the 24 months before screening, despite management considered appropriate in clinical practice for the individual ILD. Participants were randomly assigned 1:1 by means of a pseudo-random number generator to receive nintedanib 150 mg twice daily or placebo for at least 52 weeks. Participants, investigators, and other personnel involved in the trial and analysis were masked to treatment assignment until after database lock. In this subgroup analysis, we assessed the rate of decline in FVC (mL/year) over 52 weeks in patients who received at least one dose of nintedanib or placebo in five prespecified subgroups based on the ILD diagnoses documented by the investigators: hypersensitivity pneumonitis, autoimmune ILDs, idiopathic non-specific interstitial pneumonia, unclassifiable idiopathic interstitial pneumonia, and other ILDs. The trial has been completed and is registered with ClinicalTrials.gov, number NCT02999178.

FINDINGS

Participants were recruited between Feb 23, 2017, and April 27, 2018. Of 663 participants who received at least one dose of nintedanib or placebo, 173 (26%) had chronic hypersensitivity pneumonitis, 170 (26%) an autoimmune ILD, 125 (19%) idiopathic non-specific interstitial pneumonia, 114 (17%) unclassifiable idiopathic interstitial pneumonia, and 81 (12%) other ILDs. The effect of nintedanib versus placebo on reducing the rate of FVC decline (mL/year) was consistent across the five subgroups by ILD diagnosis in the overall population (hypersensitivity pneumonitis 73·1 [95% CI -8·6 to 154·8]; autoimmune ILDs 104·0 [21·1 to 186·9]; idiopathic non-specific interstitial pneumonia 141·6 [46·0 to 237·2]; unclassifiable idiopathic interstitial pneumonia 68·3 [-31·4 to 168·1]; and other ILDs 197·1 [77·6 to 316·7]; p=0·41 for treatment by subgroup by time interaction). Adverse events reported in the subgroups were consistent with those reported in the overall population.

INTERPRETATION

The INBUILD trial was not designed or powered to provide evidence for a benefit of nintedanib in specific diagnostic subgroups. However, its results suggest that nintedanib reduces the rate of ILD progression, as measured by FVC decline, in patients who have a chronic fibrosing ILD and progressive phenotype, irrespective of the underlying ILD diagnosis.

FUNDING

Boehringer Ingelheim.

IgA Antibodies Directed Against Citrullinated Protein Antigens Are Elevated in Patients With Idiopathic Pulmonary Fibrosis

BACKGROUND

The etiology of idiopathic pulmonary fibrosis (IPF) is unknown. Because it shares genetic, histopathologic, and radiographic features with the fibrosing interstitial lung disease seen in rheumatoid arthritis (RA), the goal of this study was to investigate RA-related autoantibodies in IPF.

METHODS

The study included patients with IPF from two separate cohorts at National Jewish Health and Brigham Women's Hospital (n = 181), general population control subjects (n = 160), and control subjects with disease (n = 86 [40 with RA-usual interstitial pneumonia and 46 with hypersensitivity pneumonitis]). Serum was tested for RA-associated antibodies (including IgG and IgA) to citrullinated protein antigens (ACPA). Lung tissue in 11 patients with IPF was examined for ectopic lymphoid aggregates.

RESULTS

An increased prevalence of ACPA positivity was found in two separate IPF cohorts. In particular, positivity for IgA-ACPA was increased in these two IPF cohorts compared with general population control subjects (21.3% and 24.8% vs 5.6%; P < .01). Patients with IPF were more likely to be IgA-ACPA-positive than IgG-ACPA-positive (23.2% vs 8.3%; P < .01), whereas patients with RA were more likely to be IgG-ACPA-positive than IgA-ACPA-positive (72.5% vs 52.5%; P = .04). There was a strong correlation between IgA-ACPA level and the number of ectopic lymphoid aggregates on lung histologic examination in IPF (r = 0.72; P = .01).

CONCLUSIONS

In this study, IgA-ACPA was elevated in patients with IPF and correlated with lymphoid aggregates in the lung, supporting the theory that IgA-ACPA may play a role in lung disease pathogenesis in a subset of individuals with IPF. Future studies are needed to determine whether this subset of ACPA-positive patients with IPF is distinct from patients with IPF but without antibodies.

Modelling Forced Vital Capacity in Idiopathic Pulmonary Fibrosis: Optimising Trial Design

Introduction

Forced vital capacity is the only registrational endpoint in idiopathic pulmonary fibrosis clinical trials. As most new treatments will be administered on top of standard of care, estimating treatment response will become more challenging. We developed a simulation model to quantify variability associated with forced vital capacity decline.

Methods

The model is based on publicly available clinical trial summary and home spirometry data. A single, illustrative trial setting is reported. Model assumptions are 400 subjects randomised 1:1 to investigational drug or placebo over 52 weeks, 50% of each group receiving standard of care (all-comer population), and a 90-mL treatment difference in annual forced vital capacity decline. Longitudinal profiles were simulated and the impact of varying clinical scenarios evaluated.

Results

Power to detect a significant treatment difference was 87–97%, depending on the analysis method. Repeated measures analysis generally outperformed analysis of covariance and mixed linear models, particularly with missing data (as simulated data were non-linear). A 15% yearly random dropout rate led to 0.6–5% power loss. Forced vital capacity decline-related dropout introduced greater power loss (up to 12%), as did subjects starting/stopping standard of care or investigational drug. Power was substantially lower for a 26-week trial due to the smaller assumed treatment effect at week 26 (sample size would need doubling to reach a power similar to that of a 52-week trial).

Conclusions

Our model quantifies forced vital capacity decline and associated variability, with all the caveats of background therapy, permitting robust power calculations to inform future idiopathic pulmonary fibrosis clinical trial design.

Funding

Galapagos NV (Mechelen, Belgium).

Electronic supplementary material

The online version of this article (10.1007/s12325-019-01093-3) contains supplementary material, which is available to authorized users.

Nintedanib in Progressive Fibrosing Interstitial Lung Diseases

BACKGROUND

Preclinical data have suggested that nintedanib, an intracellular inhibitor of tyrosine kinases, inhibits processes involved in the progression of lung fibrosis. Although the efficacy of nintedanib has been shown in idiopathic pulmonary fibrosis, its efficacy across a broad range of fibrosing lung diseases is unknown.

METHODS

In this double-blind, placebo-controlled, phase 3 trial conducted in 15 countries, we randomly assigned patients with fibrosing lung disease affecting more than 10% of lung volume on high-resolution computed tomography (CT) to receive nintedanib at a dose of 150 mg twice daily or placebo. All the patients met criteria for progression of interstitial lung disease in the past 24 months despite treatment and had a forced vital capacity (FVC) of at least 45% of the predicted value and a diffusing capacity of the lung for carbon monoxide ranging from 30 to less than 80% of the predicted value. Randomization was stratified according to the fibrotic pattern (a pattern of usual interstitial pneumonia [UIP] or other fibrotic patterns) on high-resolution CT. The primary end point was the annual rate of decline in the FVC, as assessed over a 52-week period. The two primary populations for analysis were the overall population and patients with a UIP-like fibrotic pattern.

RESULTS

A total of 663 patients were treated. In the overall population, the adjusted rate of decline in the FVC was -80.8 ml per year with nintedanib and -187.8 ml per year with placebo, for a between-group difference of 107.0 ml per year (95% confidence interval [CI], 65.4 to 148.5; P<0.001). In patients with a UIP-like fibrotic pattern, the adjusted rate of decline in the FVC was -82.9 ml per year with nintedanib and -211.1 ml per year with placebo, for a difference of 128.2 ml (95% CI, 70.8 to 185.6; P<0.001). Diarrhea was the most common adverse event, as reported in 66.9% and 23.9% of patients treated with nintedanib and placebo, respectively. Abnormalities on liver-function testing were more common in the nintedanib group than in the placebo group.

CONCLUSIONS

In patients with progressive fibrosing interstitial lung diseases, the annual rate of decline in the FVC was significantly lower among patients who received nintedanib than among those who received placebo. Diarrhea was a common adverse event. (Funded by Boehringer Ingelheim; INBUILD ClinicalTrials.gov number, NCT02999178.).

Risk factors for disease progression in idiopathic pulmonary fibrosis

In this retrospective study of a randomised trial of simtuzumab in idiopathic pulmonary fibrosis (IPF), prodromal decline in forced vital capacity (FVC) was significantly associated with increased risk of mortality, respiratory and all-cause hospitalisations, and categorical disease progression. Predictive modelling of progression-free survival event risk was used to assess the effect of population enrichment for patients at risk of rapid progression of IPF; C-index values were 0.64 (death), 0.69 (disease progression), and 0.72 (adjudicated respiratory hospitalisation) and 0.76 (all-cause hospitalisation). Predictive modelling may be a useful tool for improving efficiency of clinical trials with categorical end points.

MUC5B variant is associated with visually and quantitatively detected preclinical pulmonary fibrosis

BACKGROUND

Relatives of patients with familial interstitial pneumonia (FIP) are at increased risk for pulmonary fibrosis. We assessed the prevalence and risk factors for preclinical pulmonary fibrosis (PrePF) in first-degree relatives of patients with FIP and determined the utility of deep learning in detecting PrePF on CT.

METHODS

First-degree relatives of patients with FIP over 40 years of age who believed themselves to be unaffected by pulmonary fibrosis underwent CT scans of the chest. Images were visually reviewed, and a deep learning algorithm was used to quantify lung fibrosis. Genotyping for common idiopathic pulmonary fibrosis risk variants in MUC5B and TERT was performed.

FINDINGS

In 494 relatives of patients with FIP from 263 families of patients with FIP, the prevalence of PrePF on visual CT evaluation was 15.6% (95% CI 12.6 to 19.0). Compared with visual CT evaluation, deep learning quantitative CT analysis had 84% sensitivity (95% CI 0.72 to 0.89) and 86% sensitivity (95% CI 0.83 to 0.89) for discriminating subjects with visual PrePF diagnosis. Subjects with PrePF were older (65.9, SD 10.1 years) than subjects without fibrosis (55.8 SD 8.7 years), more likely to be male (49% vs 37%), more likely to have smoked (44% vs 27%) and more likely to have the MUC5B promoter variant rs35705950 (minor allele frequency 0.29 vs 0.21). MUC5B variant carriers had higher quantitative CT fibrosis scores (mean difference of 0.36%), a difference that remains significant when controlling for age and sex.

INTERPRETATION

PrePF is common in relatives of patients with FIP. Its prevalence increases with age and the presence of a common MUC5B promoter variant. Quantitative CT analysis can detect these imaging abnormalities.

Diagnosis of Idiopathic Pulmonary Fibrosis. An Official ATS/ERS/JRS/ALAT Clinical Practice Guideline

BACKGROUND

This document provides clinical recommendations for the diagnosis of idiopathic pulmonary fibrosis (IPF). It represents a collaborative effort between the American Thoracic Society, European Respiratory Society, Japanese Respiratory Society, and Latin American Thoracic Society.

METHODS

The evidence syntheses were discussed and recommendations formulated by a multidisciplinary committee of IPF experts. The evidence was appraised and recommendations were formulated, written, and graded using the Grading of Recommendations, Assessment, Development, and Evaluation approach.

RESULTS

The guideline panel updated the diagnostic criteria for IPF. Previously defined patterns of usual interstitial pneumonia (UIP) were refined to patterns of UIP, probable UIP, indeterminate, and alternate diagnosis. For patients with newly detected interstitial lung disease (ILD) who have a high-resolution computed tomography scan pattern of probable UIP, indeterminate, or an alternative diagnosis, conditional recommendations were made for performing BAL and surgical lung biopsy; because of lack of evidence, no recommendation was made for or against performing transbronchial lung biopsy or lung cryobiopsy. In contrast, for patients with newly detected ILD who have a high-resolution computed tomography scan pattern of UIP, strong recommendations were made against performing surgical lung biopsy, transbronchial lung biopsy, and lung cryobiopsy, and a conditional recommendation was made against performing BAL. Additional recommendations included a conditional recommendation for multidisciplinary discussion and a strong recommendation against measurement of serum biomarkers for the sole purpose of distinguishing IPF from other ILDs.

CONCLUSIONS

The guideline panel provided recommendations related to the diagnosis of IPF.

Acute exacerbations of fibrotic interstitial lung diseases

BACKGROUND AND OBJECTIVE

Acute exacerbation (AE) is a severe complication of idiopathic pulmonary fibrosis (AE-IPF). In 2016, an international working group revised its definition and diagnostic criteria; however, few studies have assessed the frequency and prognosis of AE in patients with other fibrotic interstitial lung diseases (FILD).

METHODS

We used data from 1019 consecutive interstitial lung disease (ILD) patients initially evaluated between January 2008 and July 2015. All subject diagnoses were made by multidisciplinary discussion in December 2018. ILD was categorized as IPF (n = 462) and other FILD which included non-specific interstitial pneumonia (n = 22), chronic hypersensitivity pneumonitis (n = 29), connective tissue disease-associated ILD (n = 205) and unclassifiable ILD (n = 209). Using the 2016 definition of AE-IPF, we identified all subjects with an AE.

RESULTS

During the observational period, 193 patients experienced a first AE (AE-FILD n = 69, AE-IPF n = 124). The time to first AE was significantly longer in FILD than IPF (log-rank test, P < 0.001). After adjusting for potentially influential confounders, FILD remained a significant predictor of longer time to first AE compared with IPF (hazard ratio: 0.453; 95% CI: 0.317-0.647, P = 0.006). In a multivariate Cox proportional analysis, baseline disease severity was closely associated with the incidence of AE-ILD. Even after adjustment for other clinical variables, AE had a negative impact on overall survival. AE-FILD and AE-IPF showed similar poor short-term outcomes.

CONCLUSION

All forms of ILD are at risk of AE and have a similar outcome to AE-IPF.