Beyond idiopathic pulmonary fibrosis: the world of progressive-fibrosing interstitial lung disease

Antifibrotic therapy in progressive pulmonary fibrosis: a review of recent advances

INTRODUCTION

Progressive pulmonary fibrosis (PPF) is a manifestation of a heterogenous group of underlying interstitial lung disease (ILD) diagnoses, defined as non-idiopathic pulmonary fibrosis (IPF) progressive fibrotic ILD meeting at least two of the following criteria in the previous 12 months: worsening respiratory symptoms, absolute decline in forced vital capacity (FVC) more than or equal to 5% and/or absolute decline in diffusing capacity for carbon monoxide (DLCO) more than or equal to 10% and/or radiological progression.

AREAS COVERED

The authors subjectively reviewed a synthesis of literature from PubMed to identify recent advances in the diagnosis and characterisation of PPF, treatment recommendations, and management challenges. This review provides a comprehensive summary of recent advances and highlights future directions for the diagnosis, management, and treatment of PPF.

EXPERT OPINION

Recent advances in defining the criteria for PPF diagnosis and licensing of treatment are likely to support further characterisation of the PPF patient population and improve our understanding of prevalence. The diagnosis of PPF remains challenging with the need for a specialised ILD multidisciplinary team (MDT) approach. The evidence base supports the use of immunomodulatory therapy to treat inflammatory ILDs and antifibrotic therapy where PPF develops. Treatment needs to be tailored to the specific underlying disease and determined on a case-by-case basis.

Current monitoring and treatment of progressive fibrosing interstitial lung disease: a survey of physicians in Japan, the United States, and the European Union

OBJECTIVE

To understand assumptions about and approaches to interstitial lung disease (ILD), including those of the progressive phenotype (progressive fibrosing ILD), this multinational survey assessed physicians' attitudes toward, knowledge of, and management strategies for progressive fibrosing ILD.

METHODS

This internet-based survey of physicians was conducted between November 2018 and February 2019. Practical management strategies for progressive fibrosing ILD, and current approaches to the assessment and treatment of ILD, were compared between countries/regions (Japan vs. United States and European Union) and specialties (pulmonologists vs. rheumatologists).

RESULTS

The survey was completed by 574 respondents. Compared with Western countries, the progressive fibrosing phenotype concept was not widely understood by Japanese respondents, with no notable differences in the understanding of this phenotype between pulmonologists and rheumatologists. Across all regions, pulmonary function tests, diffusing capacity of the lungs for carbon monoxide assessments, and pulse oximeter measurements were commonly performed at intervals of ≤6 months. In general, physicians in the United States and European Union preferred physiologic approaches for follow-up, while those in Japan preferred imaging and blood monitoring. Compared with rheumatologists, pulmonologists performed more frequent monitoring of autoimmune ILDs, and the differences between specialties were most pronounced in Japan. Regional differences in treatment approaches were observed, probably reflecting the local availability of agents and healthcare environments.

CONCLUSIONS

Awareness and management of progressive fibrosing ILD varied between specialties and regions, highlighting an unmet need for standardized diagnosis, treatment guidelines, and specialist education in this area.

Estimation of the Prevalence of Progressive Fibrosing Interstitial Lung Diseases: Systematic Literature Review and Data from a Physician Survey

Some patients with interstitial lung diseases (ILDs) other than idiopathic pulmonary fibrosis exhibit a progressive clinical phenotype. These chronic progressive fibrosing ILDs have a variety of underlying diseases, and their prevalence is currently unknown. Here we carry out the first systematic review of literature on the prevalence of fibrosing ILDs and progressive fibrosing ILDs using data from physician surveys to estimate frequency of progression among different ILDs. We searched MEDLINE and Embase for studies assessing prevalence of ILD, individual ILDs associated with fibrosis and progressive fibrosing ILDs. These were combined with data from previously published physician surveys to obtain prevalence estimates of each chronic fibrosing ILD with a progressive phenotype and of progressive fibrosing ILDs overall. We identified 16 publications, including five reporting overall ILD prevalence, estimated at 6.3-76.0 per 100,000 people in Europe (four studies) and 74.3 per 100,000 in the USA (one study). In total, 13-40% of ILDs were estimated to develop a progressive fibrosing phenotype, with overall prevalence estimates for progressive fibrosing ILDs of 2.2-20.0 per 100,000 in Europe and 28.0 per 100,000 in the USA. Prevalence estimates for individual progressive fibrosing ILDs varied up to 16.7 per 100,000 people. These conditions represent a sizeable fraction of chronic respiratory disorders and have a high unmet need.

Progressive fibrosing interstitial lung diseases: A new concept and indication of nintedanib

Many interstitial lung diseases (ILDs) are characterized by chronic progressive fibrosis. The antifibrotic agents may prevent disease progression of these diseases. Nintedanib is a triple tyrosine kinase inhibitor and has an antifibrotic effect. The proven beneficial effects of nintedanib in idiopathic pulmonary fibrosis (IPF) and systemic sclerosis (SSc)-associated ILD, nintedanib was intended for use in many other fibrotic lung diseases consistent with the concept described below. With this trial, the concept and definition of progressive fibrosing ILD (PF-ILD) were created, a type of fibrosing diseases that progresses with fibrosis measured in forced vital capacity and high-resolution CT findings and worsening of respiratory symptoms at a certain rate or faster. PF-ILDs are composed of idiopathic interstial pneumonias such as non-specific interstitial pneumonia and unclassifiable interstitial pneumonia and inhalation lung diseases such as chronic hypersensitivity pneumonia and connective tissue disease-associated ILD such as rheumatoid arthritis-related ILD and SSc-related ILD and sarcoidosis and so on. Nintedanib significantly reduced the annual rate of decline in forced vital capacity over 52 weeks compared with placebo. Nintedanib received marketing approval in the United States and Japan for the treatment of PF-ILDs. This review summarizes the new concept of PF-ILDs and effectiveness of nintedanib to PF-ILDs and discussion points to be solved in the future when using nintedanib for PF-ILDs.