An updated safety review of the drug treatments for idiopathic pulmonary fibrosis

Imaging Pulmonary Fibrosis and Treatment Efficacy In Vivo with Autotaxin-Specific PET Ligand [18F]ATX-1905

Idiopathic pulmonary fibrosis (IPF) is a fatal disease characterized by unpredictable progression and limited therapeutic options. Current diagnosis relies on high resolution computed tomography (HRCT), which may not adequately capture early signs of deterioration. The enzyme autotaxin (ATX) emerges as a prominently expressed extracellular secretory enzyme in the lungs of IPF patients. The objective of this study was to evaluate the effectiveness of 18F-labeled ATX-targeted tracer [18F]ATX-1905, in comparison with [18F]FDG, for early fibrosis diagnosis, disease evolution monitoring, and treatment efficacy assessment in bleomycin-induced pulmonary fibrosis (BPF) models. To assess treatment efficacy, mice were treated with two commonly used drugs for IPF, pirfenidone or nintedanib, from Day 9 to Day 23 postbleomycin administration. Lung tissue assessments encompassed inflammation severity via H&E staining, and Ashcroft scoring via Masson staining, alongside quantification of ATX expression through ELISA. Positron emission tomography (PET) imaging employing [18F]FDG and [18F]ATX-1905 tracked disease progression pre- and post-treatment. The extent of pulmonary fibrosis corresponded to changes in ATX expression levels in the BPF mouse model. Notably, [18F]ATX-1905 exhibited elevated uptake in BPF lungs during the progression of the disease, particularly evident at the early stage (Day 9). This uptake was inhibited by an ATX inhibitor, PF-8380, underscoring the specificity of the radiotracer. Conversely, [18F]FDG uptake, peaking at Day 15, decreased subsequently, likely reflective of diminished inflammation. A 2-week treatment regimen using either pirfenidone or nintedanib resulted in notable reductions of ATX expression levels and fibrosis degrees within lung tissues, based on ELISA and Masson staining, as evidenced by PET imaging with [18F]ATX-1905. [18F]FDG uptake also decreased following the treatment period. Additionally, PET/CT imaging extended to a nonhuman primate (NHP) BPF model. The uptake of [18F]ATX-1905 (SUVmax = 2.2) was significantly higher than that of [18F]FDG (SUVmax = 0.7) in fibrotic lung tissue. Using our novel ATX-specific radiotracer [18F]ATX-1905 and PET/CT imaging, we demonstrated excellent ability in early fibrosis detection, disease monitoring, and treatment assessment within lungs of the BPF mouse models. [18F]ATX-1905 displayed remarkable specificity for ATX expression and high sensitivity for ATX alterations, suggesting its potential for monitoring varying ATX expression in lungs of IPF patients.

Trichodelphinine A alleviates pulmonary fibrosis by inhibiting collagen synthesis via NOX4-ARG1/TGF-β signaling pathway

BACKGROUND

Pulmonary fibrosis, a progressive and fatal lung disease with no effective treatment medication, is characterized by lung remodeling and fibroblastic foci caused by an oxidative imbalance with an overloading deposition of collagen. Trichodelphinine A, a hetisine-type C20-diterpenoid alkaloid, was found anti-fibrotic activity in vitro, but its effect and mechanism on pulmonary fibrosis still unknown.

PURPOSE

Our study aimed to investigate and validate the anti-fibrotic properties of trichodelphinine A in pulmonary fibrosis animals induced by bleomycin (BLM), and its mechanism whether via NOX4-ARG1/TGF-β signaling pathway.

METHODS

The anti-fibrotic effects of trichodelphinine A were evaluated using BLM-induced rats through indicators of lung histopathology and collagen synthesis. Dynamic metabolomics evaluated the metabolic disorder and therapeutic effect of trichodelphinine A. The interaction between trichodelphinine A and NOX4 receptor was confirmed using CETSA and molecular dynamics experiments. Molecular biology experiments were conducted in NOX4 gene knockout mice to investigate the intervention effect of trichodelphinine A.

RESULTS

Trichodelphinine A could suppress histopathologic changes, collagen deposition and proinflammatory cytokine release pulmonary fibrosis in bleomycin induced rats. Dynamic metabolomics studies revealed that trichodelphinine A could correct endogenous metabolic disorders of arachidonic acid, arginine and proline during fibrosis development, which revealed that the regulation of oxidative stress and amino acid metabolism targeting NOX4 and ARG1 may be the main pharmacological mechanisms of trichodelphinine A on pulmonary fibrosis. We further determined that trichodelphinine A inhibited over oxidative stress and collagen deposition by suppressing Nrf2-keap1 and ARG1-OAT signaling pathways, respectively. Molecular dynamics studies showed that trichodelphinine A was directly binds with NOX4, in which PHE354 and THR355 residues of NOX4 are critical binding sites for trichodelphinine A. Mechanistic validation in cells or mice with NOX4 knockout or silencing suggested that the anti-fibrotic effects of trichodelphinine A depended on inhibition of NOX4 to suppress ARG1/OAT activation and TGF-β/Smads signaling pathway.

CONCLUSION

Collectively, our findings indicate a powerful anti-fibrotic function of trichodelphinine A in pulmonary fibrosis via targeting NOX4. NOX4 mediates the activation of ARG1/OAT to regulate arginase-proline metabolism, and promotes TGF-β/Smads signaling pathway, thereby affecting the collagen synthesis in pulmonary fibrosis, which is a novel finding and indicates that inhibition of NOX4 is a novel therapeutic strategy for pulmonary fibrosis.

Use of pirfenidone in fibrotic interstitial lung diseases and beyond: a review

The pathophysiological mechanisms involved in fibrotic interstitial lung diseases (FILDs) are akin to those observed in idiopathic pulmonary fibrosis (IPF), implying the potential for shared therapeutic approaches. Pirfenidone exhibits antifibrotic and anti-inflammatory properties, making it the first small-molecule drug approved for treating IPF. Pirfenidone has been utilized in IPF treatment for more than one decade. However, guidelines for progressive pulmonary fibrosis (PPF) treatment suggest that further research and evidence are needed to fully comprehend its efficacy and safety across various PPF subtypes. In recent years, numerous studies have explored the use of pirfenidone in treating non-IPF FILD. Herein, we provide an overview of the latest research data on application of pirfenidone in occupational-related ILD, connective tissue disease-associated ILD, post-coronavirus disease-2019 pulmonary fibrosis, and other conditions. We summarize the level of evidence and highlight challenges associated with using pirfenidone in different FILDs to offer clinical guidance.

Effectiveness and tolerability of antifibrotics in rheumatoid arthritis-associated interstitial lung disease

OBJECTIVE

Our aim was to investigate the effectiveness and tolerability of antifibrotics in a real-world cohort of patients with rheumatoid arthritis-associated interstitial lung diseases (RA-ILD).

METHODS

In this retrospective cohort study, we identified RA-ILD patients initiating antifibrotics at Mass General Brigham Integrated Health Care System, a large multi-hospital healthcare system in Boston, MA, USA. We used electronic query to identify all patients with at least 2 RA diagnosis codes and a prescription for either nintedanib or pirfenidone (2014-2023). All analyzed patients met 2010 American College of Rheumatology/European Alliance of Associations for Rheumatology classification criteria for RA and had definite RA-ILD according to Bongartz criteria. Data regarding pulmonary function test (PFT) results, adverse events (AEs), tolerability, and clinical data were collected. A linear mixed model with random intercept was used to compare the within-patient trajectory of the percent predicted forced vital capacity (FVCpp) within 18-months before to 18-months after antifibrotic initiation among those with these PFT data. Lung transplant-free survival and drug retention was estimated in a Kaplan-Meier analysis and a Cox regression analysis was performed to identify independent baseline factors associated with lung transplant or mortality.

RESULTS

We analyzed 74 patients with RA-ILD that initiated antifibrotics (mean age 67.8 years, 53 % male); 40 patients initiated nintedanib and 34 initiated pirfenidone. Median follow-up was 89 weeks (min 4, max 387). There was a significant improvement in the estimated slope of FVCpp after antifibrotic initiation (-0.3 % per year after initiation compared to -6.2 % per year before antifibrotic initiation, p = 0.03). Nintedanib and pirfenidone had similar FVCpp trajectory. Twenty-six patients (35 %) died and 4 (5 %) had undergone lung transplantation during follow-up. Male sex and heavy smoking were each associated with the composite outcome of lung transplant or mortality. AEs were reported in 41 (55 %) patients, with gastrointestinal (GI) AEs being most common (n = 30). The initial antifibrotic was discontinued in 34 (46 %) patients mostly due to GI AEs (n = 19). The median drug retention time was 142 weeks (95 %CI 56, 262) with no difference between nintedanib and pirfenidone (p = 0.68).

CONCLUSION

In this first real-world study of antifibrotic use dedicated to RA-ILD, antifibrotic initiation was associated with a modestly improved trajectory of FVCpp. AEs were frequently reported, particularly GI, and discontinuation was common. However, lung transplant and mortality rates were still high, emphasizing the need for further therapeutic strategies in patients with severe RA-ILD. These real-world data complement previous trial data that investigated efficacy and safety.

Treatable traits: a comprehensive precision medicine approach in interstitial lung disease

Interstitial lung disease (ILD) is a diverse group of inflammatory and fibrotic lung conditions causing significant morbidity and mortality. A multitude of factors beyond the lungs influence symptoms, health-related quality of life, disease progression and survival in patients with ILD. Despite an increasing emphasis on multidisciplinary management in ILD, the absence of a framework for assessment and delivery of comprehensive patient care poses challenges in clinical practice. The treatable traits approach is a precision medicine care model that operates on the premise of individualised multidimensional assessment for distinct traits that can be targeted by specific interventions. The potential utility of this approach has been described in airway diseases, but has not been adequately considered in ILD. Given the similar disease heterogeneity and complexity between ILD and airway diseases, we explore the concept and potential application of the treatable traits approach in ILD. A framework of aetiological, pulmonary, extrapulmonary and behavioural and lifestyle treatable traits relevant to clinical care and outcomes for patients with ILD is proposed. We further describe key research directions to evaluate the application of the treatable traits approach towards advancing patient care and health outcomes in ILD.

Caveolin-1-Related Intervention for Fibrotic Lung Diseases

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal interstitial lung disease (ILD) for which there are no effective treatments. Lung transplantation is the only viable option for patients with end-stage PF but is only available to a minority of patients. Lung lesions in ILDs, including IPF, are characterized by alveolar epithelial cell (AEC) senescence and apoptosis and accumulation of activated myofibroblasts and/or fibrotic lung (fL) fibroblasts (fLfs). These composite populations of fLfs show a high rate of basal proliferation, resist apoptosis and senescence, and have increased migration and invasiveness. They also more readily deposit ECM proteins. These features eventuate in progressive destruction of alveolar architecture and loss of lung function in patients with PF. The identification of new, safer, and more effective therapy is therefore mandatory for patients with IPF or related ILDs. We found that increased caveolin-1 and tumor suppressor protein, p53 expression, and apoptosis in AECs occur prior to and then with the proliferation of fLfs in fibrotic lungs. AECs with elevated p53 typically undergo apoptosis. fLfs alternatively demonstrate strikingly low basal levels of caveolin-1 and p53, while mouse double minute 2 homolog (mdm2) levels and mdm2-mediated degradation of p53 protein are markedly increased. The disparities in the expression of p53 in injured AECs and fLfs appear to be due to increased basal expression of caveolin-1 in apoptotic AECs with a relative paucity of caveolin-1 and increased mdm2 in fLfs. Therefore, targeting caveolin-1 using a caveolin 1 scaffolding domain peptide, CSP7, represents a new and promising approach for patients with IPF, perhaps other forms of progressive ILD or even other forms of organ injury characterized by fibrotic repair. The mechanisms of action differ in the injured AECs and in fLfs, in which differential signaling enables the preservation of AEC viability with concurrent limitation of fLf expansion and collagen secretion. The findings in three models of PF indicate that lung scarring can be nearly abrogated by airway delivery of the peptide. Phase 1 clinical trial testing of this approach in healthy volunteers has been successfully completed; Phase 1b in IPF patients is soon to be initiated and, if successful, will be followed by phase 2 testing in short order. Apart from the treatment of IPF, this intervention may be applicable to other forms of tissue injury characterized by fibrotic repair.

Long-Term Safety of Antifibrotic Drugs in IPF: A Real-World Experience

Pirfenidone and nintedanib are the only two drugs approved for the treatment of idiopathic pulmonary fibrosis (IPF). Both proved to be safe and well-tolerated in clinical trials, but real-world data and direct comparisons are scarce. This real-life study explored the safety profile of pirfenidone and nintedanib with a prolonged follow-up. We retrospectively collected clinical status, adverse events (AEs), and treatment changes from IPF patients who had started an antifibrotic treatment at our centre from December 2011 to December 2020, including 192 patients treated with pirfenidone and 89 with nintedanib. The majority of patients in both groups experienced one or more AEs during the follow-up. A higher proportion of AEs in the nintedanib group were effectively treated with behavioural modifications or additional medications compared with the pirfenidone group (52.5% vs. 40.6%, p = 0.04). Overall, a difference in the impact of AEs due to nintedanib versus pirfenidone resulted in a lower permanent discontinuation of therapy (8.3% vs. 18.3%, p = 0.02), with the latter being associated with a higher risk of drug discontinuation at 48 months after initiation (OR = 2.52, p = 0.03). Our study confirms the safety profile of antifibrotic drugs in IPF but highlights that AEs due to nintedanib are usually easier to manage and lead to fewer cases of permanent discontinuation of therapy.

Nintedanib regulates intestinal smooth muscle hyperplasia and phenotype in vitro and in TNBS colitis in vivo

Chronic inflammation of the human intestine in Crohn’s disease (CD) causes bowel wall thickening, which typically progresses to stricturing and a recurrent need for surgery. Current therapies have limited success and CD remains idiopathic and incurable. Recent evidence shows a key role of intestinal smooth muscle cell (ISMC) hyperplasia in stricturing, which is not targeted by current anti-inflammatory therapeutics. However, progression of idiopathic pulmonary fibrosis, resembling CD in pathophysiology, is controlled by the tyrosine kinase inhibitors nintedanib (NIN) or pirfenidone, and we investigated these drugs for their effect on ISMC. In a culture model of rat ISMC, NIN inhibited serum- and PDGF-BB-stimulated growth and cell migration, and promoted the differentiated phenotype, while increasing secreted collagen. NIN did not affect signaling through PDGF-Rβ or NFκB but did inhibit cytokine-induced expression of the pro-inflammatory cytokines IL-1β and TNFα, supporting a transcriptional level of control. In TNBS-induced colitis in mice, which resembles CD, NIN decreased ISMC hyperplasia as well as expression of TNFα and IL-1β, without effect in control animals. NIN also inhibited growth of human ISMC in response to human serum or PDGF-BB, which further establishes a broad range of actions of NIN that support further trial in human IBD.

The effect of additional antimicrobial therapy on the outcomes of patients with idiopathic pulmonary fibrosis: a systematic review and meta-analysis

Background

The effect of additional antimicrobial agents on the clinical outcomes of patients with idiopathic pulmonary fibrosis (IPF) is unclear.

Methods

We performed comprehensive searches of randomized control trials (RCTs) that compared the clinical efficacy of additional antimicrobial agents to those of placebo or usual care in the treatment of IPF patients. The primary outcome was all-cause mortality, and the secondary outcomes were changes in forced vital capacity (FVC), diffusing capacity of the lung for carbon monoxide (DLCO), and the risk of adverse events (AEs).

Results

Four RCTs including a total of 1055 patients (528 receiving additional antibiotics and 527 receiving placebo or usual care) were included in this meta-analysis. Among the study group, 402 and 126 patients received co-trimoxazole and doxycycline, respectively. The all-cause mortality rates were 15.0% (79/528) and 14.0% (74/527) in the patients who did and did not receive additional antibiotics, respectively (odds ratio [OR] 1.07; 95% confidence interval [CI] 0.76 to 1.51; p = 0.71). No significant difference was observed in the changes in FVC (mean difference [MD], 0.01; 95% CI − 0.03 to 0.05; p = 0.56) and DLCO (MD, 0.05; 95% CI − 0.17 to 0.28; p = 0.65). Additional use of antimicrobial agents was also associated with an increased risk of AEs (OR 1.65; 95% CI 1.19 to 2.27; p = 0.002), especially gastrointestinal disorders (OR 1.54; 95% CI 1.10 to 2.15; p = 0.001).

Conclusions

In patients with IPF, adding antimicrobial therapy to usual care did not improve mortality or lung function decline but increased gastrointestinal toxicity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01839-0.