Ji Hoon Jang

Progressive pulmonary fibrosis (PPF) is an emerging subset of fibrotic interstitial lung diseases (ILD), defined by progressive fibrosis despite standard treatment in patients with other than idiopathic pulmonary fibrosis. The international guidelines recommended the use of nintedanib for PPF, while evidence supporting pirfenidone remains insufficient. In this study, we aimed to evaluate the efficacy and safety of pirfenidone in treating PPF. In this retrospective single-center study, we analyzed clinical data from patients with PPF who were treated with pirfenidone. Lung function data from six months before and after pirfenidone treatment were collected to assess changes over time. Missing values were imputed using a general linear mixed model (GLMM) for longitudinal data analysis. Of 33 subjects, the median age was 65.0 years, and 51.5% were female. Rheumatoid arthritis-related ILD was the most common subtype (45.5%). The median daily dose of pirfenidone was 600 mg, with a median treatment duration of 7.3 months. GLMM analysis showed a significant forced vital capacity (FVC) improvement, from −114 mL in the 6 months before treatment to +47.3 mL in the 6 months after treatment (p = 0.001). All adverse events related to pirfenidone were mild. In conclusion, the use of pirfenidone in PPF can potentially reduce the rate of FVC decline in real clinical practice.

Connective tissue disease-associated interstitial lung disease (CTD-ILD) represents a significant cause of morbidity and mortality. It is characterized by the progressive convergence of chronic inflammation, immune dysregulation, and fibrotic remodeling in the lung parenchyma. While often conceptualized through a model of idiopathic pulmonary fibrosis (IPF), CTD-ILD is fundamentally an immune-driven pathology with distinct inflammatory mechanisms in which adaptive immunity plays a profound role. This narrative review explores the “inflammation–immunity–fibrosis continuum” in CTD-ILD, elaborating the intricate cellular and molecular pathways that distinguish it from IPF. We highlight the central role of persistent T-cell responses and B-cell dysregulation, which often occur within organized tertiary lymphoid structures in the lung. This review examines how these immune processes are propagated by multiple cytokine pathways, including the TGF-β/SMAD, JAK/STAT, and phosphodiesterase-4 signaling pathways, which serve as crucial links between inflammation and fibrosis. This distinct immune mechanism in CTD-ILD explains why immunomodulatory agents are a cornerstone of CTD-ILD treatment, in contrast to their limited efficacy in IPF, and emphasizes the current paradigm of combining immunosuppression with antifibrotic drugs to target the dual drivers of the disease.

Background: This study evaluated the role of blood Krebs von den Lungen-6 (KL-6) in predicting acute exacerbation (AE) in patients with idiopathic pulmonary fibrosis (IPF). Methods: From April 2018 to March 2023, clinical data of 233 IPF patients with baseline and follow-up KL-6 values at Haeundae Paik Hospital were retrospectively analyzed. AE was defined following the criteria proposed by Collard et al. in 2016. Results: The mean age was 71.8 years; 79% were male. During follow-up (median: 18.7 months), 33 (14.2%) patients experienced AE. Throughout the entire period from baseline, KL-6 values were higher in the AE group compared to the non-AE group (P < 0.001), and the patterns of change over time also showed significant differences between both groups (P < 0.001). The KL-6 values in the post-exacerbation phase were higher than those in the pre-exacerbation phase among the AE group (P = 0.004). The AE group showed lower 1-year (86.4% vs. 95.9%) and 3-year (50.2% vs. 91.4%) survival rates compared to the non-AE group (P < 0.001). The occurrence of AE (hazard ratio (HR) 74.09, 95% confidence interval (CI) 31.97–171.7, P < 0.001) and higher lactate dehydrogenase (HR 1.02, 95% CI: 1.01–1.02, P < 0.001) were independently associated with mortality in patients with IPF Conclusions: Our data suggest that the trend in changes in KL-6 values may be utilized as a tool for predicting AE-IPF. Further research is needed to establish the clinical significance of changes in KL-6 for predicting AE-IPF and to validate the cut-off values for prediction.

Lee JH, et al. J Korean Med Sci. 2025 Jul;40:e212. https://doi.org/10.3346/jkms.2025.40.e212

Pulmonary hypertension (PH) associated with interstitial lung disease (ILD) (PH-ILD) significantly worsens clinical symptoms and survival, with no effective treatment available. This case report presents the successful treatment of PH-ILD with inhaled iloprost in a patient with idiopathic pulmonary fibrosis (IPF). The patient, a 68-year-old female, was diagnosed with IPF in 2018 and was maintained on pirfenidone. She experienced stable disease until March 2023, when she developed progressive exertional dyspnea, despite stability indicated by a computed tomography (CT) scan, without progression. Transthoracic echocardiography (TTE) and right heart catheterization (RHC) confirmed PH-ILD with a mean pulmonary artery pressure (mPAP) of 43 mmHg. Due to the ineffectiveness of sildenafil and a CT scan indicating stable IPF, a repeat RHC was performed, which showed a worsening of PH (mPAP 62 mmHg). Consequently, inhaled iloprost, at a dosage of 10 mcg every eight hours, was added to the existing antifibrotic agent. After two months, the patient experienced reduced exertional dyspnea and home oxygen requirements. By the seventh month, pulmonary function tests, the six-minute walk test, and RHC parameters (mPAP 37 mmHg) showed marked improvements. This case suggests that inhaled iloprost may be beneficial for managing PH-ILD. Further research is needed to confirm the efficacy of iloprost in PH-ILD treatment.

Interstitial lung disease (ILD) encompasses a heterogeneous group of more than 200 diffuse parenchymal lung diseases with various clinical courses. Disease progression is one of the most important prognostic factors, and, the definition of progressive pulmonary fibrosis (PPF) has recently been established. This study aimed to estimate the prevalence, risk factors, and prognosis of PPF among patients with non-idiopathic pulmonary fibrosis (IPF) in real-world practice. A total of 215 patients were retrospectively analyzed between January 2010 and June 2023 at the Haeundae Paik Hospital in the Republic of Korea. According to the criteria proposed in 2022 by Raghu et al, PPF defined as a condition that satisfies 2 or more of the following in the past year: worsening of respiratory symptoms, physiological evidence of disease progression, and radiological evidence of disease progression. The median age of the subjects was 67 years and 63.7% were female. A total of 40% was diagnosed with PPF and connective tissue disease-associated ILD (52.3%) was the most common type, followed by nonspecific interstitial pneumonitis (NSIP) (25.6%) and cryptogenic organizing pneumonitis (16.3%). In multivariate logistic regression for predicting PPF, both the use of steroids and immunosuppressants (OR: 2.57, 95% CI: 1.41–4.67, P = .002) and home oxygen use (OR: 25.17, 95% CI: 3.21–197.24, P = .002) were independent risk factors. During the follow-up period, the mortality rate was significantly higher in the PPF group than in the non-PPF group (24.4% vs 2.3%, P < .001). In the survival analysis using the Cox proportional hazard regression model, disease progression, older age and lower forced vital capacity (FVC) were independent risk factors for mortality. Our study demonstrated that the prevalence of PPF was 40%. Concomitant therapy of steroids with an immunosuppressants and home oxygen use are risk factors for PPF. PPF itself was significantly associated with high mortality rates. Risk factors for mortality were disease progression, older age, and lower FVC.

Background: Rheumatoid arthritis-associated interstitial lung disease (RA-ILD) is a common extra-articular clinical manifestation of rheumatoid arthritis (RA) that has negative impacts on morbidity and mortality. In addition, there has been no proven treatment for RA-ILD to date. Thus, we planned a meta-analysis of a literature search to confirm the clinical effects of antifibrotic agents in RA-ILD patients. Materials and Methods: We conducted the literature search in Ovid MEDLIVE^® databases, Cochrane Library databases, EMBASE, and KoreaMed and identified references elucidating the role of nintedanib or pirfenidone in adult patients with RA-ILD. Among the identified studies, those with comparative interventions, complete results of clinical trials, and available full text were included in the analysis. The primary outcome was the effect of the antifibrotic agent on disease progression in RA-ILD patients assessed with a mean difference in the change of forced vital capacity (FVC) and the proportion of patients with an increase in percent predicted FVC of 10% or more over 52 weeks. Analysis for heterogeneity was assessed through I² statistics. Meta-analysis with a fixed effect model was performed on changes in FVC. Results: A total of 153 articles were identified through database searches, of which 28 were excluded because of duplication. After additional screening, 109 studies were selected with full text and two articles qualified for analysis according to the set inclusion and exclusion criteria. As a result, two randomized controlled studies were selected, comparing nintedanib and pirfenidone to placebo, respectively. The meta-analysis revealed that antifibrotic agents showed a significant reduction in FVC decline compared to placebo in patients with RA-ILD (mean difference, 88.30; 95% CI, 37.10–139.50). Additionally, there were significantly fewer patients experienced an increase in percent predicted FVC of 10% or more in the antifibrotic agent group compared to the placebo group (Odds ratio 0.42; 95% CI 0.19–0.95, p = 0.04). There was no significant heterogeneity between the two included studies (χ² = 0.35, p = 0.0007, I² = 0%). Conclusions: The meta-analysis suggests that nintedanib and pirfenidone may have clinical utility in reducing disease progression in patients with RA-ILD. Further research is needed to confirm the clinical benefits of antifibrotic agents in RA-ILD.

Background: Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic lung disease with a poor prognosis. Pirfenidone is approved and widely used for the treatment of IPF and reduces lung function decline. The aim of this study was to evaluate the efficacy of different doses of pirfenidone for the prevention of disease progression in patients with IPF. Methods: This was a prospective, observational, single-center cohort study conducted in Haeundae Paik Hospital, Republic of Korea, from April 2021 to March 2023. IPF patients were assigned to three groups according to the dose of pirfenidone (600 mg, 1200 mg, 1800 mg). Disease progression was defined as an absolute decline to ≥5% of forced vital capacity (FVC) (% predicted value) or an absolute decline to ≥10% of diffusing capacity of the lung for carbon monoxide (DLco) (% predicted value) over 12 months. The primary endpoint was to evaluate the clinical effects of pirfenidone of each dosage on disease progression in IPF patients by comparing the FVC (% predicted value) and DLco (% predicted value) values over 12 months. The secondary endpoint was to evaluate the prognostic value of Krebs von den Lungen-6 (KL-6) in the disease progression in IPF patients using the baseline KL-6 value and the change in KL-6 values between the baseline and 12 months. Results: A total of 44 patients were enrolled, of whom 39 completed the study, with 13 patients assigned to each of the three groups. The median age was 71.7 years, and 79.5% of patients were men. The baseline characteristics were similar across groups, except the 600 mg group was older (75.9 vs. 69.2 vs. 68.2 years, p = 0.016). The overall median change in FVC and DLco over 12 months was −2.7% (IQR: −9.1%, −1.2%) and −3.8% (IQR: −13.6%, −3.7%), respectively. There was no difference in the decline in FVC (change in FVC, % predicted value: −3.23 vs. −4.08 vs. −1.54, p = 0.621) and DLco (change in DLco, % predicted value: 0.00 vs. −3.62 vs. −3.15, p = 0.437) among the three groups. Fourteen patients (35.9%) suffered disease progression. The rate of disease progression did not differ according to the dose of pirfenidone (38.5 vs. 38.5 vs. 30.8%, p = 1.000). In multivariable logistic regression analysis, KL-6 was not a statistically significant predictor of disease progression. Conclusions: In our study, regardless of dose, consistent pirfenidone use for 12 months resulted in similar efficacy for the prevention of disease progression in patients with IPF. Large-scale, randomized, double-blind, placebo-controlled clinical trials are needed.

Background: Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic lung disease with a poor prognosis. Pirfenidone is approved and widely used for the treatment of IPF and reduces lung function decline. The aim of this study was to evaluate the efficacy of different doses of pirfenidone for the prevention of disease progression in patients with IPF. Methods: This was a prospective, observational, single-center cohort study conducted in Haeundae Paik Hospital, Republic of Korea, from April 2021 to March 2023. IPF patients were assigned to three groups according to the dose of pirfenidone (600mg, 1,200mg, 1,800mg). The primary endpoint was the efficacy of pirfenidone according to dose for the prevention of disease progression over 12 months. The secondary endpoint was the role of Krebs von den Lungen-6 (KL-6) in predicting disease progression. Results: A total of 44 patients were enrolled, of whom 39 completed the study, with 13 patients assigned to each of the three groups. The median age was 71.7 years, and 79.5% of patients were men. The baseline characteristics were similar across groups, except the 600mg group was older (75.9 vs. 69.2 vs. 68.2 years, p = 0.016). Fourteen patients (35.9%) suffered disease progression. The rate of disease progression did not differ according to the dose of pirfenidone (38.5 vs. 38.5 vs. 30.8%, p = 1.000). In multivariable logistic regression analysis, KL-6 was not a statistically significant predictor of disease progression. Conclusions: In our study, regardless of dose, consistent pirfenidone use for 12 months resulted in similar efficacy for the prevention of disease progression in patients with IPF. Large-scale, randomized, double-blind, placebo-controlled clinical trials are needed.

Background: This study evaluated the efficacy and safety of pulmonary rehabilitation (PR) on functional performance, exercise-related oxygen saturation, and health-related quality of life among patients with idiopathic pulmonary fibrosis (IPF). Methods: A total of 25 patients with IPF (13 in the PR group and 12 in the non-PR group) were enrolled between August 2019 and October 2021 at Haeundae-Paik Hospital in the Republic of Korea. A cardiopulmonary exercise test (CPET), six-minute walk test (6MWT), pulmonary function test (PFT), Saint George’s Respiratory Questionnaire (SGRQ), muscle strength test, and bioelectrical impedance analysis were performed in each group at baseline and after eight weeks of PR. Results: The mean age was 68 years of age and most subjects were male. Baseline characteristics were similar between the two groups. The distance during 6MWT after PR was significantly improved in the PR group (inter-group p-value = 0.002). VO₂max and VE/VCO₂ slopes showed a significant difference after eight weeks only in the PR group, but the rate of change did not differ significantly from the non-PR group. Total skeletal muscle mass, PFT variables, and SGRQ scores did not differ significantly between the groups. Conclusions: PR improved exercise capacity, as measured using CPET and 6 MWT. Further studies in larger samples are needed to evaluate the long-term efficacy of PR in IPF patients.