Advances in Targeted Therapy for Progressive Fibrosing Interstitial Lung Disease

Analysis of treatment efficacy, tolerability, and survival of patients receiving antifibrotic therapy for progressive nonidiopathic pulmonary fibrosis

BACKGROUND

There are still disagreements about diagnostic criteria and treatment of progressive pulmonary fibrosis (PPF). Real-life data and survival analyses have a guiding role in clarifying this issue.

METHODS

In this multicenter retrospective cohort study, real-life data of adult patients diagnosed with PPF and treated with antifibrotics for at least 6 months were examined.

RESULTS

Of the 222 patients, 161 were treated with Nintedanib (N) and 61 with Pirfenidone (P). The most common PPF subtype was connective tissue disease-related interstitial lung disease (CTD-ILD) (53.2%). The progression rate was significantly higher in patients with usual interstitial pneumonia (UIP) (P = 0.003). A -3.1% (-49.2 ml) decrease was detected in forced vital capacity (FVC) in the 6th month. The 6th month and overall progression-free survival (PFS) rates were 83.3% and 51.8%. The 6th month and overall clinical event-free survival (CEFS) rates were 89.6% and 53.6%. The survival rates for 6th, 12th, and entire follow-up periods were found to be 98.2%, 89.2%, and 77.5%. CT-ILD had the longest survival time (166.5 ± 9.2 months) and fibrotic hypersensitivity pneumonia had the shortest survival time (87.6 ± 9.2 months) (P = 0.011). N was advantageous in patients with UIP in terms of FVC loss and estimated survival. While PFS during the entire follow-up period was in favor of N, CEFS had no significant difference between drugs.

CONCLUSION

PPF subtypes have significant differences in terms of prognosis and survival. The effect of AF drugs on progression varies, especially among radiological patterns. An individualized approach is required in the diagnosis, follow-up, and treatment of patients with PPF.

Lack of diversity in antifibrotic trials for pulmonary fibrosis: a systematic review

INTRODUCTION

Social determinants of health (SDH), including age, sex, ethnicity, socioeconomic status and rurality, influence health outcomes. Clinical trials investigating antifibrotic agents for people with idiopathic pulmonary fibrosis (IPF) have been conducted in predominantly White and male populations; it is unclear whether other SDH have been considered. This study aimed to investigate active consideration and reporting of SDH in clinical trials of antifibrotic agents for people with IPF.

METHODS

Three registries (ClinicalTrials.gov, ANZCTR and International Standard Randomised Controlled Trial Number (ISRCTN)) plus CENTRAL (Cochrane Central Register of Controlled Trials) were searched for clinical trials investigating antifibrotic agents for people with IPF or various progressive fibrotic ILD variants registered from 1 January 2000 until 3 September 2023. Data were extracted regarding trial phase/status, recruitment strategies and eligibility criteria. If trial results were available, SDH data from demographics and subgroup analyses were extracted.

RESULTS

Of 313 records identified, 70 trials were included. The majority of trials were phase II or III (77%), 56% were completed and 61% had reported results that included eight terminated trials. All 70 trials specified age and sex, but not other SDH, within their eligibility criteria. Of 43 trials reporting results, all reported age and sex and 40 (95%) reported ethnicity. 10 387 participants were described (74% male, 77% White, 16% Asian and <1% Black). Descriptors for ethnicity varied considerably. Five trials (12%) included only White participants and three (7%) included only Asian participants. No other SDH were reported.

CONCLUSIONS

SDH beyond age, sex and ethnicity were neither considered nor reported in antifibrotic IPF trials. Trial populations were predominantly male and White. There is a need to actively consider SDH to ensure diverse and representative clinical trial populations.

Spatial and phenotypic heterogeneity of resident and monocyte-derived macrophages during inflammatory exacerbations leading to pulmonary fibrosis

Introduction

Genetic mutations in critical nodes of pulmonary epithelial function are linked to the pathogenesis of pulmonary fibrosis (PF) and other interstitial lung diseases. The slow progression of these pathologies is often intermitted and accelerated by acute exacerbations, complex non-resolving cycles of inflammation and parenchymal damage, resulting in lung function decline and death. Excess monocyte mobilization during the initial phase of an acute exacerbation, and their long-term persistence in the lung, is linked to poor disease outcome.

Methods

The present work leverages a clinical idiopathic PF dataset and a murine model of acute inflammatory exacerbations triggered by mutation in the alveolar type-2 cell-restricted Surfactant Protein-C [SP-C] gene to spatially and phenotypically define monocyte/macrophage changes in the fibrosing lung.

Results

SP-C mutation triggered heterogeneous CD68+ macrophage activation, with highly active peri-injured cells relative to those sampled from fully remodeled and healthy regions. Ingenuity pathway analysis of sorted CD11b-SigF+CD11c+ alveolar macrophages defined asynchronous activation of extracellular matrix re-organization, cellular mobilization, and Apolipoprotein E (Apoe) signaling in the fibrosing lung. Cell-cell communication analysis of single cell sequencing datasets predicted pro-fibrogenic signaling (fibronectin/Fn1, osteopontin/Spp1, and Tgfb1) emanating from Trem2/TREM2 + interstitial macrophages. These cells also produced a distinct lipid signature from alveolar macrophages and monocytes, characterized by Apoe expression. Mono- and di-allelic genetic deletion of ApoE in SP-C mutant mice had limited impact on inflammation and mortality up to 42 day after injury.

Discussion

Together, these results provide a detailed spatio-temporal picture of resident, interstitial, and monocyte-derived macrophages during SP-C induced inflammatory exacerbations and end-stage clinical PF, and propose ApoE as a biomarker to identify activated macrophages involved in tissue remodeling.

The dorsal muscle group area at the T12 vertebral level as a risk factor for tolerability of nintedanib in patients with idiopathic pulmonary fibrosis or other progressive fibrosing interstitial lung diseases

Nintedanib, a multi-intracellular tyrosine kinase inhibitor, reduces progression of idiopathic pulmonary fibrosis (IPF) and has been approved to use in other progressive fibrosing interstitial lung diseases (ILD) recently. However, the factors that affect the discontinuation of treatment due to adverse events is uncertain. The dorsal muscle group area at the T12 vertebral level (T12DMA) assessed on computed tomography (CT) images has been reported to be associated with mortality in chronic obstructive pulmonary disease (COPD) and other diseases. The relationship between T12DMA and the discontinuation of nintedanib remains unclear.

METHODS

39 patients with IPF or other progressive fibrosing ILDs who started nintedanib at a regular dose (300 mg/day) were enrolled. We compared the characteristics between patients who stopped nintedanib at a regular dose before 6 months and/or continue to take nintedanib at a low dose (150 mg/day) and patients who were still taking nintedanib at a regular dose over 6 months. This study retrospectively investigated clinical parameters including T12DMA index (T12DMA/height2) to evaluate whether these parameters might serve as risk factor for the tolerability of nintedanib in patients with IPF and other progressive fibrosing ILDs.

RESULTS

Discontinuation or dose reductions of nintedanib due to adverse events were observed in 14 (35.8%) patients. A multiple logistic regression model showed T12DMA index to be the only significant risk factor for predicting for the early termination of nintedanib (odd rate, 0.549; 95% confidence interval, 0.327-0.922; P = .023).

CONCLUSIONS

This study revealed that T12DMA index was a risk factor for the early termination of nintedanib. The initial dose of nintedanib adjusted to the differences in skeletal muscle mass and careful management of adverse events may contribute to the longer nintedanib treatment, which would lead to a better clinical outcome.

Radiation-Induced Lung Injury With Lung Cancer Treated With the Combination Therapy of Nintedanib and Dexamethasone

Radiation-induced lung injury (RILI) associated with lung cancer becomes refractory. Nintedanib is a multi-kinase inhibitor that suppresses the development of pulmonary fibrosis. Herein, we report a case of RILI with progressive pulmonary fibrosis after stereotactic body radiation therapy in a 70-year-old man with lung cancer. The patient responded well to the initial prednisolone therapy but became resistant during tapering. The combination therapy of nintedanib and dexamethasone resulted in a temporary improvement in RILI. Nintedanib is not a standard therapy for RILI, and further investigation is needed to evaluate the effects of nintedanib on RILI complicated by lung cancer.

HSP47: A Therapeutic Target in Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease characterized by a progressive decline in lung function and poor prognosis. The deposition of the extracellular matrix (ECM) by myofibroblasts contributes to the stiffening of lung tissue and impaired oxygen exchange in IPF. Type I collagen is the major ECM component and predominant collagen protein deposited in chronic fibrosis, suggesting that type I collagen could be a target of drugs for fibrosis treatment. Heat shock protein 47 (HSP47), encoded by the serpin peptidase inhibitor clade H, member 1 gene, is a stress-inducible collagen-binding protein. It is an endoplasmic reticulum-resident molecular chaperone essential for the correct folding of procollagen. HSP47 expression is increased in cellular and animal models of pulmonary fibrosis and correlates with pathological manifestations in human interstitial lung diseases. Various factors affect HSP47 expression directly or indirectly in pulmonary fibrosis models. Overall, understanding the relationship between HSP47 expression and pulmonary fibrosis may contribute to the development of novel therapeutic strategies.

Guidelines of the Polish Respiratory Society on the Diagnosis and Treatment of Progressive Fibrosing Interstitial Lung Diseases Other than Idiopathic Pulmonary Fibrosis

The recommendations were developed as answers to previously formulated questions concerning everyday diagnostic and therapeutic challenges. They were developed based on a review of the current literature using the GRADE methodology. The experts suggest that PF-ILD be diagnosed based on a combination of different criteria, such as the aggravation of symptoms, progression of radiological lesions, and worsening of lung function test parameters. The experts recommend a precise diagnosis of an underlying disease, with serological testing for an autoimmune disease always being included. The final diagnosis should be worked out by a multidisciplinary team (MDT). Patients with an interstitial lung disease other than IPF who do not meet the criteria for the progressive fibrosis phenotype should be monitored for progression, and those with systemic autoimmune diseases should be regularly monitored for signs of interstitial lung disease. In managing patients with interstitial lung disease associated with autoimmune diseases, an opinion of an MDT should be considered. Nintedanib rather than pirfenidon should be introduced in the event of the ineffectiveness of the therapy recommended for the treatment of the underlying disease, but in some instances, it is possible to start antifibrotic treatment without earlier immunomodulatory therapy. It is also admissible to use immunomodulatory and antifibrotic drugs simultaneously. No recommendations were made for or against termination of anti-fibrotic therapy in the case of noted progression during treatment of a PF-ILD other than IPF. The experts recommend that the same principles of non-pharmacological and palliative treatment and eligibility for lung transplantation should be applied to patients with an interstitial lung disease other than IPF with progressive fibrosis as in patients with IPF.

2,3,5,4′-tetrahydroxystilbene-2-O-β-D-glucoside ameliorates bleomycin-induced pulmonary fibrosis via regulating pro-fibrotic signaling pathways

2,3,5,4′-Tetrahydroxystilbene-2-O-β-D-Glucoside (THSG) is the main active ingredient extracted from Polygonum multiflorum Thunb. (PMT), which has been reported to possess extensive pharmacological properties. Nevertheless, the exact role of THSG in pulmonary fibrosis has not been demonstrated yet. The main purpose of this study was to investigate the protective effect of THSG against bleomycin (BLM)-induced lung fibrosis in a murine model, and explore the underlying mechanisms of THSG in transforming growth factor-beta 1 (TGF-β1)-induced fibrogenesis using MRC-5 human lung fibroblast cells. We found that THSG significantly attenuated lung injury by reducing fibrosis and extracellular matrix deposition. THSG treatment significantly downregulated the expression levels of TGF-β1, fibronectin, α-SMA, CTGF, and TGFBR2, however, upregulated the expression levels of antioxidants (SOD-1 and catalase) and LC3B in the lungs of BLM-treated mice. THSG treatment decreased the expression levels of fibronectin, α-SMA, and CTGF in TGF-β1-stimulated MRC-5 cells. Conversely, THSG increased the expression levels of SOD-1 and catalase. Furthermore, treatment of THSG profoundly reduced the TGF-β1-induced generation of reactive oxygen species (ROS). In addition, THSG restored TGF-β1-induced impaired autophagy, accompany by increasing the protein levels of LC3B-II and Beclin 1. Mechanism study indicated that THSG significantly reduced TGF-β1-induced increase of TGFBR2 expression and phosphorylation of Smad2/3, Akt, mTOR, and ERK1/2 in MRC-5 cells. These findings suggest that THSG may be considered as an anti-fibrotic drug for the treatment of pulmonary fibrosis.

Prognostic Predictive Characteristics in Patients With Fibrosing Interstitial Lung Disease: A Retrospective Cohort Study

Background: Limited data are available regarding the entire spectrum of interstitial lung disease with a progressive fibrosing feature. We investigated the prevalence and prognostic predictive characteristics in patients with PF-ILD.

Methods: This retrospective cohort study included patients with fibrosing ILD who were investigated between 1 January 2015 and 30 April 2021. We recorded clinical features and outcomes to identify the possible risk factors for fibrosing progression as well as mortality.

Results: Of the 579 patients with fibrosing ILD, 227 (39.21%) met the criteria for progression. Clubbing of fingers [odds ratio (OR) 1.52, 95% confidence interval (CI) 1.03 to 2.24, p = 0.035] and a high-resolution computed tomography (HRCT)-documented usual interstitial pneumonia (UIP)-like fibrotic pattern (OR 1.95, 95% CI 1.33 to 2.86, p = 0.001) were risk factors for fibrosis progression. The mortality was worse in patients with PF with hypoxemia [hazard ratio (HR) 2.08, 95% CI 1.31 to 3.32, p = 0.002], in those with baseline diffusion capacity of the lung for carbon monoxide (DLCO) % predicted &lt;50% (HR 2.25, 95% CI 1.45 to 3.50, p &lt; 0.001), or in those with UIP-like fibrotic pattern (HR 1.68, 95% CI 1.04 to 2.71, p &lt; 0.001).

Conclusion: Clubbing of fingers and an HRCT-documented UIP-like fibrotic pattern were more likely to be associated with progressive fibrosing with varied prevalence based on the specific diagnosis. Among patients with progressive fibrosing, those with hypoxemia, lower baseline DLCO% predicted, or UIP-like fibrotic pattern showed poor mortality.

Anti-Inflammatory and/or Anti-Fibrotic Treatment of MPO-ANCA-Positive Interstitial Lung Disease: A Short Review

The presence of a lung lesion is common in microscopic polyangiitis (MPA), and interstitial lung disease (ILD) can lead to a poor prognosis. Although myeloperoxidase antineutrophil cytoplasmic antibodies (MPO-ANCA) are often present in patients with MPA, patients with ILD and MPO-ANCA positivity but without other manifestations of systemic vasculitis have also been reported. Therefore, the possible association between MPO-ANCA, MPA, and idiopathic ILD remains unclear. This problematic matter has influenced the treatment strategy of MPO-ANCA-positive ILD patients without systemic vasculitis. Clinicians should undertake treatment with careful consideration of the four major causes of death in MPO-ANCA-positive ILD: acute exacerbation of ILD, progressive lung fibrosis, infectious comorbidities, and diffuse alveolar hemorrhage. Further, clinicians need to carefully judge whether inflammation or fibrosis is the dominant condition with reference to the patient’s clinical domain and radiopathological lung features. Recently, anti-fibrotic agents such as nintedanib and pirfenidone were shown to be effective in treating various etiologies associated with ILD and have thus led to the widening of treatment options. In this review, the clinical characteristics, radiopathology, prognosis, and therapeutic options in patients with MPO-ANCA-positive ILD are summarized using limited information from previous studies.

Nintedanib in Progressive Pulmonary Fibrosis: A Systematic Review and Meta-Analysis

Background: To inform an American Thoracic Society, European Respiratory Society, Japanese Respiratory Society, and Asociación Latinoamericana del Tórax clinical practice guideline, this systematic review evaluated existing interstitial lung disease (ILD) literature to determine whether patients with progressive pulmonary fibrosis (PPF) should be treated with the antifibrotic nintedanib. Methods: A literature search was conducted across MEDLINE, EMBASE, and Cochrane databases through December 2020 for studies using nintedanib to treat patients with PPF. Mortality, disease progression, and adverse event data were extracted, and meta-analyses performed when possible. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) Working Group approach was used to assess the quality of evidence. Results: Two relevant studies were selected. The annual decline in FVC was less in the nintedanib arm in the overall study population [mean difference (MD) 107 milliliters (mL)/year (yr) (95% CI 65.4-148.5 mL/yr)] and in the subgroups with usual interstitial pneumonia (UIP) pattern of pulmonary fibrosis [MD 128.2 mL/yr (95% CI 70.8-185.6 mL/yr)], non-UIP patterns of pulmonary fibrosis [MD 75.3 mL/yr (95% CI 15.5-135.0 mL/yr)], fibrotic connective tissue disease-related ILD [MD 106.2 mL/yr (95% CI 10.6-201.9 mL/yr)], fibrotic idiopathic non-specific interstitial pneumonia [MD 141.7 mL/yr (95% CI 46.0-237.4 mL/yr)], and fibrotic occupational ILD [MD 252.8 mL/yr (95% CI 79.2-426.5 mL/yr)], but not fibrotic hypersensitivity pneumonitis [MD 72.9 mL/yr (95% CI -8.9-154.7 mL/yr)], fibrotic sarcoidosis [MD -20.5 mL/yr (95% CI -337.1-296.1 mL/yr)], or unclassified fibrotic ILD [MD 68.5 mL/yr (95% CI -31.3-168.4 mL/yr)] when compared to placebo. Gastrointestinal (GI) side effects were common. Quality of evidence for the outcomes ranged from very low to moderate GRADE. Conclusions: Nintedanib use in patients with PPF is associated with a statistically significant decrease in disease progression but increase in GI side effects regardless of the radiographic pattern of pulmonary fibrosis. However, limitations in the available evidence lead to low certainty in these effect estimates and make definitive conclusions about the differential effects by subtype of ILD difficult to determine.

Pirfenidone in Progressive Pulmonary Fibrosis: A Systematic Review and Meta-Analysis

Background: To inform an American Thoracic Society, European Respiratory Society, Japanese Respiratory Society, and Asociación Latinoamericana del Tórax clinical practice guideline, this systematic review evaluated existing interstitial lung disease literature to determine whether patients with progressive pulmonary fibrosis (PPF) should be treated with the antifibrotic pirfenidone. Methods: A literature search was conducted across MEDLINE, EMBASE, and Cochrane databases through December 2020 for studies using pirfenidone to treat patients with PPF. Mortality, disease progression, lung function, and adverse event data were extracted, and meta-analyses performed when possible. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) Working Group approach was used to assess the quality of evidence. Results: Two studies met inclusion criteria. Meta-analyses revealed changes in FVC % predicted [mean difference (MD) 2.3% (95% CI 0.5-4.1)], FVC in mL [MD 100.0 mL (95% CI 98.1-101.9)], and 6MWD in meters [MD 25.2 m (95% CI 8.3-42.1)] all favored pirfenidone to placebo. Change in DLCO in mmol/kPa/min [MD 0.40 mmol/kPa/min (95% CI 0.10-0.70)] and risk of DLCO declining more than 15% [relative risk (RR) 0.27 (95% CI 0.08-0.95)] also favored pirfenidone. The risks of gastrointestinal discomfort [RR 1.83 (95% CI 1.29-2.60)] and photosensitivity [RR 4.88 (95% CI 1.09-21.83)] were higher with pirfenidone. The quality of evidence was low or very low GRADE, depending on the outcome. Conclusions: Pirfenidone use in patients with PPF is associated with statistically significant decrease in disease progression and protection in lung function. However, there is very low certainty in the estimated effects due to limitations in the available evidence.

Claims-based Prevalence of Disease Progression among Patients with Non-IPF Fibrosing Interstitial Lung Disease in the US

Rationale

Chronic fibrosing interstitial lung disease (ILD) with a progressive phenotype is a clinical concept describing the broad group of ILDs characterized by progressive pulmonary fibrosis. The prevalence of progressive fibrotic ILDs other than idiopathic pulmonary fibrosis (IPF) is not well understood.

Objectives

We used a novel algorithm to estimate the prevalence range of disease progression among patients with non-IPF fibrotic ILD in a U.S. claims database.

Methods

This was a retrospective study including adults with commercial or Medicare Advantage with Part D (MAPD) insurance using administrative claims data from October 2015 to September 2019. Patients likely to have non-IPF fibrosing ILD with a progressive phenotype were identified via an algorithm that incorporated ILD-related diagnosis codes (excluding IPF) and claims-based proxies for fibrotic ILD progression, including pulmonary function tests, chest imaging, oral corticosteroid (OCS) medications, immunosuppressive medications, lung transplant, oxygen therapy, palliative care, and respiratory hospitalization. The prevalence range of non-IPF fibrotic ILD with progressive disease behavior was calculated using strict and lenient case definitions to account for potential imprecision in the progression proxies.

Results

Of nearly 9 million study-eligible patients, 17,136 were identified with non-IPF fibrosing ILD. The prevalence of disease progression per 10,000 (95% confidence interval) ranged from 12.14 (11.74–12.54) to 29.05 (28.43–29.67) over a mean observation time of 1.44 years for MAPD enrollees (n = 14,686), and from 0.89 (0.81–0.97) to 2.36 (2.24–2.48) over a mean observation time of 1.29 years for commercial enrollees (n = 2,450). Prevalence estimates increased with age for both insurance types. Among patients with progression, 4,097 met at least two progression proxies not considering OCS (strict case definition) and 9,946 met at least one progression proxy (lenient case definition). The mean (standard deviation) number of proxies met was 2.1 (1.3), and the most common individual proxies met (alone or in combination with other proxies) were OCS use (48.9%), respiratory hospitalization (44.2%), and oxygen therapy (44.1%).

Conclusions

This is among the first claims-based estimates of the prevalence of non-IPF chronic fibrosing ILD with a progressive phenotype. Our analysis indicates that this phenotype is rare in the overall population but increases substantially with increasing age.

A case of welder's pneumoconiosis treated with corticosteroid followed by nintedanib

A 32-year-old man who had worked as a welder for 13 years was hospitalized for a fever and hemosputum with dyspnea. He was diagnosed with welding fume-associated lung disease with alveolar hemorrhaging and acute respiratory failure. Despite surviving the acute phase with corticosteroid therapy, hypoxemia persisted after a month and a half, requiring home oxygen therapy. As a result of the introduction of nintedanib, his clinical findings gradually improved, and the patient was weaned from oxygen therapy after six months. Inhalation of a large amount of welding fumes in a short period can cause alveolar hemorrhaging and prolonged pulmonary dysfunction.

Decision-Making Strategy for the Treatment of Rheumatoid Arthritis-Associated Interstitial Lung Disease (RA-ILD)

Rheumatoid arthritis (RA) is a common type of autoimmune arthritis. Patient clinical outcomes might be influenced by numerous respiratory diseases, but interstitial lung disease (ILD) is the most important comorbidity. RA-associated ILD (RA-ILD) is divided into acute/subacute and chronic forms. In the acute/subacute course, if the disease is severe as indicated by a diffuse alveolar damage pattern, high-dose corticosteroids combined with antimicrobial agents should be promptly initiated while considering the differential diagnoses, primarily acute exacerbation (AE) of RA-ILD, drug-induced pneumonitis, and Pneumocystis pneumonia. As initial therapeutic management in the chronic course, the RA itself should be stabilized without delay; thereafter, the activity of ILD itself can be stabilized, considering the safety of each anti-rheumatic drug. The formation of the usual interstitial pneumonia (UIP) pattern is the most important determinant because lung function can worsen more quickly with this pattern. However, because clinicians can fail to identify specific radiological patterns, it is important to determine whether each patient with RA-ILD has UIP-like lesions such as subpleural reticulation, traction bronchiectasis, and honeycombing especially progressively enlarged cysts. In patients with progressive RA-ILD and high risk for infection or AE of ILD in whom fibrosis is dominant, clinicians should consider starting an anti-fibrotic agent.

From pulmonary fibrosis to progressive pulmonary fibrosis: a lethal pathobiological jump

The month of September is Pulmonary Fibrosis Awareness Month. In this context, we would like to highlight the concept of progressive pulmonary fibrosis, a common denominator/phenotype of many interstitial lung diseases other than idiopathic pulmonary fibrosis, leading to clinical deterioration, decreased quality of life, and high mortality.

Prevalence and Incidence of Chronic Fibrosing Interstitial Lung Diseases with a Progressive Phenotype in the United States Estimated in a Large Claims Database Analysis

INTRODUCTION

Many fibrosing interstitial lung diseases (ILDs) develop a chronic progressive phenotype. While idiopathic pulmonary fibrosis, which is always progressive, is well characterized with established treatment options, the epidemiology of other chronic fibrosing ILDs with a progressive phenotype has not been widely investigated. Treatment options are limited, with a high unmet need. This claims database study estimates the incidence and prevalence of these diseases in the USA.

METHODS

Diagnosis, procedure and resource utilization codes from insurance claims were used to identify patients with fibrosing ILD and those with a chronic progressive phenotype among 37,565,644 adult patients in the IBM® MarketScan® Research Database 2012-2015. Two eligible ILD claims were required for a fibrosing ILD diagnosis. Progression was defined using a novel algorithm constituted by criteria considered proxies for progression. Patients were defined as having incident (new) or existing diagnoses based on claims during a 365-day period before study entry.

RESULTS

The estimated age- and sex-adjusted prevalence per 100,000 persons of fibrosing ILD (95% confidence interval) was 117.82 (116.56, 119.08) and of chronic fibrosing ILDs with a progressive phenotype was 70.30 (69.32, 71.27). The estimated adjusted incidence per 100,000 patient-years of fibrosing ILD was 51.56 (50.88, 52.24) and of chronic fibrosing ILDs with a progressive phenotype was 32.55 (32.01, 33.09). Among incident fibrosing ILD patients, 57.3% experienced progression over a median of 117 days (interquartile range 63-224), with largely comparable rates of progression among different diseases.

CONCLUSIONS

Chronic fibrosing ILDs with a progressive phenotype comprise a relatively new disease construct requiring varied approaches to obtain reliable estimates of prevalence and incidence. This is the first large claims database study using real-world data to provide estimates of the prevalence and incidence of these diseases among a very large segment of the US population and could form the groundwork for future studies.

Pathology, Radiology, and Genetics of Interstitial Lung Disease in Patients With Shortened Telomeres

Interstitial lung diseases (ILDs) in patients with shortened telomeres have not been well characterized. We describe demographic, radiologic, histopathologic, and molecular features, and p16 expression in patients with telomeres ≤10th percentile (shortened telomeres) and compare them to patients with telomere length >10th percentile. Lung explants, wedge biopsies, and autopsy specimens of patients with telomere testing were reviewed independently by 3 pathologists using defined parameters. High-resolution computed tomography scans were reviewed by 3 radiologists. p16-positive fibroblast foci were quantified. A multidisciplinary diagnosis was recorded. Patients with shortened telomeres (N=26) were morphologically diagnosed as usual interstitial pneumonia (UIP) (N=11, 42.3%), chronic hypersensitivity pneumonitis (N=6, 23.1%), pleuroparenchymal fibroelastosis, fibrotic nonspecific interstitial pneumonia, desquamative interstitial pneumonia (N=1, 3.8%, each), and fibrotic interstitial lung disease (fILD), not otherwise specified (N=6, 23.1%). Patients with telomeres >10th percentile (N=18) showed morphologic features of UIP (N=9, 50%), chronic hypersensitivity pneumonitis (N=3, 16.7%), fibrotic nonspecific interstitial pneumonia (N=2, 11.1%), or fILD, not otherwise specified (N=4, 22.2%). Patients with shortened telomeres had more p16-positive foci (P=0.04). The number of p16-positive foci correlated with outcome (P=0.0067). Thirty-nine percent of patients with shortened telomeres harbored telomere-related gene variants. Among 17 patients with shortened telomeres and high-resolution computed tomography features consistent with or probable UIP, 8 (47.1%) patients showed morphologic features compatible with UIP; multidisciplinary diagnosis most commonly was idiopathic pulmonary fibrosis (N=7, 41.2%) and familial pulmonary fibrosis (N=5, 29%) in these patients. In conclusion, patients with shortened telomeres have a spectrum of fILDs. They often demonstrate atypical and discordant features on pathology and radiology leading to diagnostic challenges.

Antifibrotic Therapies and Progressive Fibrosing Interstitial Lung Disease (PF-ILD): Building on INBUILD

Progressive fibrosing interstitial lung disease (PF-ILD) describes a phenotypic subset of interstitial lung diseases characterized by progressive, intractable lung fibrosis. PF-ILD is separate from, but has radiographic, histopathologic, and clinical similarities to idiopathic pulmonary fibrosis. Two antifibrotic medications, nintedanib and pirfenidone, have been approved for use in patients with idiopathic pulmonary fibrosis. Recently completed randomized controlled trials have demonstrated the clinical efficacy of antifibrotic therapy in patients with PF-ILD. The validation of efficacy of antifibrotic therapy in PF-ILD has changed the treatment landscape for all of the fibrotic lung diseases, providing a new treatment pathway and opening the door for combined antifibrotic and immunosuppressant drug therapy to address both the fibrotic and inflammatory components of ILD characterized by mixed pathophysiologic pathways.

Causes of acute respiratory hospitalizations predict survival in fibrosing interstitial lung diseases

Acute exacerbation of ILD (AE-ILD) is a common reason for hospitalization; it is also associated with significant mortality. Less is known about the prognostic significance of other events causing acute, non-elective hospitalizations in ILD patients. ILD patients hospitalized due to acute respiratory worsening were collected from medical records. Reasons for respiratory deterioration were classified into AE-ILDs and other causes. Clinical features and survival data of idiopathic pulmonary fibrosis (IPF) and other types of ILDs were evaluated and compared. In all, 237 patients (138 with IPF and 99 with other ILD) fulfilled the inclusion criteria. Of the non-IPF ILD types, the most prevalent subgroups were connective tissue disease-associated ILD (n = 33) and asbestosis (n = 22). The most common cause for hospitalization was AE-ILD explaining 41% of hospitalizations. Lower respiratory tract infection (22%), subacute progression of ILD (12%) and cardiovascular causes (7.2%) were other common reasons for hospital treatment. Patients with a lower respiratory tract infection had a more favorable prognosis compared with patients with AE-ILD. AE-ILDs were less fatal than cardiovascular or concurrent non-ILD-related causes for hospitalizations in non-IPF patients. High Gender-Age-Physiology (GAP) index was a marker for shortened survival and earlier AE-ILDs in all patients. IPF patients had a significantly shorter overall and post-hospitalization survival time compared with other ILDs. Most respiratory hospitalizations in ILD patients were related to causes other than AE-ILD, which highlights the importance of accurate differential diagnosis in order to target the appropriate treatment for each ILD patient.