Assessing the Effectiveness of Pirfenidone in Idiopathic Pulmonary Fibrosis: Long-Term, Real-World Data from European IPF Registry (eurIPFreg)

Treatment of idiopathic pulmonary fibrosis: an update on emerging drugs in phase II & III clinical trials

INTRODUCTION

Idiopathic pulmonary fibrosis (IPF) is a progressive, debilitating lung disease with poor prognosis. Although two antifibrotics have been approved in the past decade there are no curative therapies.

AREAS COVERED

This review highlights the current landscape of IPF research in the development of novel compounds for the treatment of IPF while also evaluating repurposed medications and their role in the management of IPF. The literature search includes studies found on PubMed, conference abstracts, and press releases until March 2024.

EXPERT OPINION

Disease progression in IPF is driven by a dysregulated cycle of microinjury, aberrant wound healing, and propagating fibrosis. Current drug development focuses on attenuating fibrotic responses via multiple pathways. Phosphodiesterase 4 inhibitors (PDE4i), lysophosphatidic acid (LPA) antagonists, dual-selective inhibitor of αvβ6 and αvβ1 integrins, and the prostacyclin agonist Treprostinil have had supportive phase II clinical trial results in slowing decline in forced vital capacity (FVC) in IPF. Barriers to drug development specific to IPF include the lack of a rodent model that mimics IPF pathology, the nascent understanding of the role of genetics affecting development of IPF and response to treatment, and the lack of a validated biomarker to monitor therapeutic response in patients with IPF. Successful treatment of IPF will likely include a multi-targeted approach anchored in precision medicine.

Compare three diagnostic criteria of progressive pulmonary fibrosis

Background

In patients with fibrotic interstitial lung disease (ILD), a progressive pulmonary fibrosis (PPF) typically demonstrates worsening respiratory symptoms, lung function decline and continuing fibrosis. The goal of this study was to compare the three different diagnostic criteria of PPF.

Methods

Except for idiopathic pulmonary fibrosis (IPF), all consecutive adult patients with fibrotic ILD were retrospectively examined for the three predefined diagnostic criteria of PPF. The three criteria assessed the disease progression in preceding 6 (0.5-year), 12 (1-year) and 24 (2-year) months respectively. The clinical characteristics, decline in predicted percent of forced vital capacity (FVC%) and survival of three groups were compared, followed by determination of risk factors for mortality.

Results

We identified 246 patients by 0.5-year standard, 154 patients by 1-year standard and 281 patients by 2-year standard. Among them, 95% of patients in 1-year group were also included in 2-year group. The average 1-year decline in FVC% was -1.0%, -2.7%, and -4.1% for 0.5-, 1-, and 2-year group respectively. The 4-year survival rate was 74% in 0.5-year group, 66% in 1-year group, and 62% in 2-year group. In multivariate Cox model, only baseline predicted percent diffusing capacity of the lungs for carbon monoxide (DLCO%) <50% was correlated with mortality, with a hazard ratio of 3.4 (95% CI: 1.1-10.6, P=0.03).

Conclusions

In the current situations, both the 1- and 2-year criterion are the reasonable choice to define PPF both in researches and clinical practice, and DLCO% is an independent predictor for mortality of PPF.

Improved Survival of IPF patients Treated With Antifibrotic Drugs Compared With Untreated Patients

PURPOSE

Pirfenidone and nintedanib unequivocally inhibit FVC decline, but have been inconsistently linked to reduced mortality in phase III studies. On the contrary, real-world data show a survival benefit of antifibrotic drugs. However, it is unknown what this benefit is across different Gender, Age, and Physiology (GAP) stages.

RESEARCH QUESTIONS

Is there a difference in transplant-free (TPF) survival of IPF patients receiving antifibrotic drugs (IPFAF) compared with an untreated cohort (IPFnon-AF)? Is this different for patients with GAP stage I, II, or III.

METHODS

This is a single-center observational cohort study using prospectively included patients diagnosed with IPF between 2008-2018. Primary outcomes were TPF survival difference and 1-, 2-, and 3-year cumulative mortality for IPFAF and IPFnon-AF. This was repeated after stratification for GAP stage.

RESULTS

In total, 457 patients were included. The median transplant-free survival was 3.4 years in IPFAF (n = 313) and 2.2 years in IPFnon-AF (n = 144, p = 0.005). For GAP stage II, a median survival of 3.1 and 1.7 years was noted for IPFAF (n = 143) and IPFnon-AF (n = 59, p < 0.001), respectively. A significantly lower 1-, 2-, and 3- year cumulative mortality was found for IPFAF with GAP stage II (1 yr: 7.0% vs 35.6%, 2 yr: 26.6% vs 55.9%, and 3 yr: 46.9% vs 69.5%). The 1-year cumulative mortality of IPFAF with GAP III was also significantly lower (19.0% vs 65.0%).

CONCLUSION

This large real-world study showed a survival benefit in IPFAF compared with IPFnon-AF. This especially holds true for patients with GAP stage II and III.

Telomere length associates with chronological age and mortality across racially diverse pulmonary fibrosis cohorts

Pulmonary fibrosis (PF) is characterized by profound scarring and poor survival. We investigated the association of leukocyte telomere length (LTL) with chronological age and mortality across racially diverse PF cohorts. LTL measurements among participants with PF stratified by race/ethnicity were assessed in relation to age and all-cause mortality, and compared to controls. Generalized linear models were used to evaluate the age-LTL relationship, Cox proportional hazards models were used for hazard ratio estimation, and the Cochran-Armitage test was used to assess quartiles of LTL. Standardized LTL shortened with increasing chronological age; this association in controls was strengthened in PF (R = -0.28; P < 0.0001). In PF, age- and sex-adjusted LTL below the median consistently predicted worse mortality across all racial groups (White, HR = 2.21, 95% CI = 1.79-2.72; Black, HR = 2.22, 95% CI = 1.05-4.66; Hispanic, HR = 3.40, 95% CI = 1.88-6.14; and Asian, HR = 2.11, 95% CI = 0.55-8.23). LTL associates uniformly with chronological age and is a biomarker predictive of mortality in PF across racial groups.

Factors associated with dose reduction of pirfenidone in patients with idiopathic pulmonary fibrosis: A study based on real-world clinical data

INTRODUCTION

Although pirfenidone slows disease progression in patients with idiopathic pulmonary fibrosis (IPF), in clinical practice, patients often cannot tolerate the recommended dose because of several adverse events. This study aimed to investigate adverse events associated with pirfenidone and factors associated with dose reduction.

METHODS

This single-center retrospective cohort study included 156 consecutive patients with IPF who received pirfenidone. Demographic characteristics, pulmonary function, and pirfenidone-related adverse events were investigated. We compared patients who received standard and reduced doses of pirfenidone.

RESULTS

The mean patient age was 69.7 years. The median follow-up duration was 243 days. The low-dose group (n = 73) included older patients (71.0 years vs. 67.4 years, p = 0.016), fewer smokers (80.8% vs. 96.4%, p = 0.008), and patients with a lower body mass index (BMI; 24.1 kg/m2 vs. 25.7 kg/m2, p = 0.027) than the standard dose group (n = 57). Multivariate logistic regression analysis revealed that older age (odds ratio = 1.066, p = 0.016) was significantly associated with dose reduction of pirfenidone after adjusting for sex, smoking history, emphysema, and BMI. No significant difference was found in the rates of a reduced forced vital capacity and diffusing capacity for carbon monoxide between the two groups.

CONCLUSIONS

Although older patients are more likely to undergo dose reduction of pirfenidone, low-dose pirfenidone might be effective for treating patients with IPF. Low-dose pirfenidone could be considered an effective treatment option for older patients with IPF.

Analysis of the safety and efficacy of different plasma concentrations of pirfenidone in patients with idiopathic pulmonary fibrosis

The high incidence and mortality of idiopathic pulmonary fibrosis (IPF) have led to the widespread use of antifibrotic drugs such as pirfenidone; however, the associated adverse reactions greatly vary among individuals and the dose is not fixed. To date, no reliable blood concentration range of pirfenidone is available to monitor adverse reactions and clinical efficacy. This real study assessed the efficacy and safety of different plasma concentrations of pirfenidone in patients with IPF. The study included 99 patients with IPF orally treated with pirfenidone capsules for at least 52 weeks. Ultra-performance liquid chromatography–mass spectrometry was used to analyze drug plasma concentrations. The annual rate of forced vital capacity (FVC) decline, assessed at week 52, was set as the primary end point. Secondary end points were the change from the baseline in the 6-min walk distance (6 MWD) and the time to the first acute exacerbation of IPF, both of which evaluated over 52 weeks. In the total population, the annual FVC decline in the high-concentration group was −90.0 ml per year versus −260.0 ml per year in the low-concentration group, for a between-group difference of 190.3 ml per year. The proportion of patients treated with high plasma concentrations of pirfenidone who showed an absolute decline of ≥10% in FVC% predicted, with a 6 MWD reduction of ≥50 m, or died, was lower than that of patients treated with low plasma concentrations of pirfenidone. High concentrations of pirfenidone reduced the risk of acute exacerbation in patients with IPF. Considerable differences were not observed for the total St. George’s Respiratory Questionnaire score or the rates of death between the high- and low-concentration groups. Mild to moderate adverse events, mainly involving the gastrointestinal system and the skin, were more common in the high-concentration group than in the low-concentration group but did not lead to termination of treatment in most cases. Our results suggest that treatment of IPF with high blood concentration of pirfenidone is both safe and effective. In the case of tolerable adverse reactions, patients with IPF may benefit from high concentrations of pirfenidone.

Targeting Histone Deacetylases in Idiopathic Pulmonary Fibrosis: A Future Therapeutic Option

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal lung disease with limited therapeutic options, and there is a huge unmet need for new therapies. A growing body of evidence suggests that the histone deacetylase (HDAC) family of transcriptional corepressors has emerged as crucial mediators of IPF pathogenesis. HDACs deacetylate histones and result in chromatin condensation and epigenetic repression of gene transcription. HDACs also catalyse the deacetylation of many non-histone proteins, including transcription factors, thus also leading to changes in the transcriptome and cellular signalling. Increased HDAC expression is associated with cell proliferation, cell growth and anti-apoptosis and is, thus, a salient feature of many cancers. In IPF, induction and abnormal upregulation of Class I and Class II HDAC enzymes in myofibroblast foci, as well as aberrant bronchiolar epithelium, is an eminent observation, whereas type-II alveolar epithelial cells (AECII) of IPF lungs indicate a significant depletion of many HDACs. We thus suggest that the significant imbalance of HDAC activity in IPF lungs, with a “cancer-like” increase in fibroblastic and bronchial cells versus a lack in AECII, promotes and perpetuates fibrosis. This review focuses on the mechanisms by which Class I and Class II HDACs mediate fibrogenesis and on the mechanisms by which various HDAC inhibitors reverse the deregulated epigenetic responses in IPF, supporting HDAC inhibition as promising IPF therapy.

A scalable 3D tissue culture pipeline to enable functional therapeutic screening for pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a lethal lung disease targeting the alveolar gas exchange apparatus, leading to death by asphyxiation. IPF progresses on a tissue scale through aberrant matrix remodeling, enhanced cell contraction, and subsequent microenvironment densification. Although two pharmaceuticals modestly slow progression, IPF patient survival averages less than 5 years. A major impediment to therapeutic development is the lack of high-fidelity models that account for the fibrotic microenvironment. Our goal is to create a three-dimensional (3D) platform to enable lung fibrosis studies and recapitulate IPF tissue features. We demonstrate that normal lung fibroblasts encapsulated in collagen microspheres can be pushed toward an activated phenotype, treated with FDA-approved therapies, and their fibrotic function quantified using imaging assays (extracellular matrix deposition, contractile protein expression, and microenvironment compaction). Highlighting the system's utility, we further show that fibroblasts isolated from IPF patient lungs maintain fibrotic phenotypes and manifest reduced fibrotic function when treated with epigenetic modifiers. Our system enables enhanced screening due to improved predictability and fidelity compared to 2D systems combined with superior tractability and throughput compared to 3D systems.

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

INTRODUCTION

The approval of antifibrotic agents nintedanib and pirfenidone revolutionized the management of idiopathic pulmonary fibrosis (IPF). These treatments showed acceptable tolerability in randomized-clinical trials; however, they have been associated with a spectrum of potential side effects which require careful assessment of risks and benefits in the individual patient before commencing and during antifibrotic therapy.

AREAS COVERED

The accrued evidence on safety of nintedanib and pirfenidone is summarized, from the first randomized clinical trials to the open-label extension studies and post-marketing clinical experiences which helped clarify the long-term tolerability of these drugs.

EXPERT OPINION

The data collected over the last years confirmed the comparable tolerability profile of nintedanib and pirfenidone. The physician's assessment of expected side effects may help decide the optimal first-line therapy for the individual patient. Patient's counseling during treatment remains essential to manage emerging adverse events and eventually inform the decision of drug discontinuation.