The evolving pharmacotherapy of pulmonary fibrosis

Thalidomide interaction with inflammation in idiopathic pulmonary fibrosis

The "Thalidomide tragedy" is a landmark in the history of the pharmaceutical industry. Despite limited clinical trials, there is a continuous effort to investigate thalidomide as a drug for cancer and inflammatory diseases such as rheumatoid arthritis, lepromatous leprosy, and COVID-19. This review focuses on the possibilities of targeting inflammation by repurposing thalidomide for the treatment of idiopathic pulmonary fibrosis (IPF). Articles were searched from the Scopus database, sorted, and selected articles were reviewed. The content includes the proven mechanisms of action of thalidomide relevant to IPF. Inflammation, oxidative stress, and epigenetic mechanisms are major pathogenic factors in IPF. Transforming growth factor-β (TGF-β) is the major biomarker of IPF. Thalidomide is an effective anti-inflammatory drug in inhibiting TGF-β, interleukins (IL-6 and IL-1β), and tumour necrosis factor-α (TNF-α). Thalidomide binds cereblon, a process that is involved in the proposed mechanism in specific cancers such as breast cancer, colon cancer, multiple myeloma, and lung cancer. Cereblon is involved in activating AMP-activated protein kinase (AMPK)-TGF-β/Smad signalling, thereby attenuating fibrosis. The past few years have witnessed an improvement in the identification of biomarkers and diagnostic technologies in respiratory diseases, partly because of the COVID-19 pandemic. Hence, investment in clinical trials with a systematic plan can help repurpose thalidomide for pulmonary fibrosis.

The added value of pirfenidone to fight inflammation and fibrotic state induced by SARS-CoV-2 : Anti-inflammatory and anti-fibrotic therapy could solve the lung complications of the infection?

Aim

SARS-CoV-2 infection has been divided by scientific opinion into three phases: the first as asymptomatic or slightly symptomatic and the second and the third with greater severity, characterized by a hyperinflammatory and fibrotic state, responsible for lung lesions, in some cases fatal. The development of antiviral drugs directed against SARS-CoV-2 and effective vaccines is progressing; meanwhile, the best pharmacological objective is related to the management of all the complications caused by this viral infection, mainly controlling the inflammatory and fibrotic state and preventing the infection from moving into the most serious phases.

Subject and method

Describe the scientific rationale related to the use of an antifibrotic therapy with pirfenidone, as monotherapy and/or in combination with anti-inflammatory drugs to manage and control complications of SARS-CoV-2 infection.

Results

Based on the scientific literature and epidemiological results and considering the pathophysiological, biological, and molecular characteristics of SARS-CoV-2, an antifibrotic drug such as pirfenidone as monotherapy or in combination with anti-inflammatory drugs can be (acting early, at the right doses and at the right time) therapeutically effective to avoid serious complications during viral infection. The same approach can also be effective as postinfection therapy in patients with residual pulmonary fibrotic damage. Management of inflammation and fibrotic status with a combination therapy of pirfenidone and IL-6 or IL-1 inhibitors could represent a pharmacological synergy with added value.

Conclusion

In this article, we consider the role of antifibrotic therapy with pirfenidone in patients with SARS-CoV-2 infection on going or in the stage of postinfection with pulmonary fibrotic consequences. The scientific rationale for its use is also described.

Antioxidants and NOX1/NOX4 inhibition blocks TGFβ1-induced CCN2 and α-SMA expression in dermal and gingival fibroblasts

TGFbeta induces fibrogenic responses in fibroblasts. Reactive oxygen species (ROS)/nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) may contribute to fibrogenic responses. Here, we examine if the antioxidant N-acetylcysteine (NAC), the NOX inhibitor diphenyleneiodonium (DPI) and the selective NOX1/NOX4 inhibitor GKT-137831 impairs the ability of TGFbeta to induce profibrotic gene expression in human gingival (HGF) and dermal (HDF) fibroblasts. We also assess if GKT-137831 can block the persistent fibrotic phenotype of lesional scleroderma (SSc) fibroblasts. We use real-time polymerase chain reaction and Western blot analysis to evaluate whether NAC and DPI impair the ability of TGFbeta1 to induce expression of fibrogenic genes in fibroblasts. The effects of GKT-137831 on TGFbeta-induced protein expression and the persistent fibrotic phenotype of lesional scleroderma (SSc) fibroblasts were tested using Western blot and collagen gel contraction analyses. In HDF and HGF, TGFbeta1 induces CCN2, CCN1, endothelin-1 and alpha-smooth muscle actin (SMA) in a fashion sensitive to NAC. Induction of COL1A1 mRNA was unaffected. Similar results were seen with DPI. NAC and DPI impaired the ability of TGFbeta1 to induce protein expression of CCN2 and alpha-SMA in HDF and HGF. GKT-137831 impaired TGFbeta-induced CCN2 and alpha-SMA protein expression in HGF and HDF. In lesional SSc dermal fibroblasts, GKT-137831 reduced alpha-SMA and CCN2 protein overexpression and collagen gel contraction. These results are consistent with the hypothesis that antioxidants or NOX1/4 inhibition may be useful in blocking profibrotic effects of TGFbeta on dermal and gingival fibroblasts and warrant consideration for further development as potential antifibrotic agents.

Efficacy of N-Acetylcysteine in Idiopathic Pulmonary Fibrosis: A Systematic Review and Meta-Analysis

There are a number of conflicting reports describing the clinical outcomes of using N-acetylcysteine for the treatment of idiopathic pulmonary fibrosis. We have, therefore, performed a meta-analysis to evaluate the efficacy of N-acetylcysteine, compared with control, for the treatment of idiopathic pulmonary fibrosis.Original controlled clinical trials evaluating the efficacy of N-acetylcysteine for the treatment of idiopathic pulmonary fibrosis were included in the analysis. Searches for relevant articles were carried out in July 2014 by 2 independent researchers using PubMed, Embase, Cochrane Central, and Google Scholar. Change in forced vital capacity, change in percentage of predicted vital capacity, change in percentage of predicted carbon monoxide diffusing capacity, changes in 6 minutes walking test distance, rate of adverse events, and rate of death were expressed as outcomes using RevMan 5.0.1.Five trials, with a total of 564 patients, were included in this meta-analysis. The meta-analysis showed that the control group had significant decreases in percentage of predicted vital capacity (standardized mean difference [SMD] = 0.37; 95% confidence interval [CI]: 0.13 to -0.62; P = 0.003) and 6 minutes walking test distance (SMD = 0.25; 95% CI: 0.02-0.48; P = 0.04). There were no statistically significant differences in forced vital capacity (SMD = 0.07; 95% CI: -0.13-0.27; P = 0.52), percentage of predicted carbon monoxide diffusing capacity (SMD = 0.12; 95% CI: -0.06-0.30; P = 0.18), rates of adverse events (odd ratio = 4.50; 95% CI: 0.19-106.41; P = 0.35), or death rates (odd ratio = 1.79; 95% CI: 0.3-5.12; P = 0.28) between the N-acetylcysteine group and the control group.N-Acetylcysteine was found to have a significant effect only on decreases in percentage of predicted vital capacity and 6 minutes walking test distance. N-acetylcysteine showed no beneficial effect on changes in forced vital capacity, changes in predicted carbon monoxide diffusing capacity, rates of adverse events, or death rates.

Novel drug targets for idiopathic pulmonary fibrosis

Idiopathic Pulmonary Fibrosis (IPF) is a progressive, fatal lung disorder of unknown cause with a highly variable and unpredictable clinical course. The advances made in deciphering IPF pathobiology over the last decades have led to the approval of two anti-fibrotic molecules, pirfenidone and nintedanib, that showed to be effective in significantly reducing the rate of progression of the disease. Such pharmacological breakthroughs represent a dramatic change in the management of these patients and are reflected in updated international guidelines. However, the need to find a cure for this devastating disease remains unmet and the development of novel therapeutic agents remains hurdled by several factors. Here, we review the latest insights into therapeutic approaches for IPF and the available evidence for the most promising novel compounds currently under development, and discuss the challenges and evolution of IPF clinical research over the next few years.

Treatment patterns, resource use and costs of idiopathic pulmonary fibrosis in Spain--results of a Delphi Panel

Background

Idiopathic pulmonary fibrosis (IPF) is a form of chronic fibrosing interstitial pneumonia characterized by progressive worsening of dyspnea and lung function, with a poor prognosis. The objective of this study was to determine treatment patterns, resource use and costs of managing Spanish patients with IPF.

Methods

A three-round Delphi consensus panel of 15 clinical experts was held between December 2012 and June 2013 using questionnaires to describe the management of patients with IPF. A cost analysis based on Delphi panel estimates was made from the Spanish National Health System (NHS) perspective, including the direct costs of IPF diagnosis and management. Unit costs were applied to Delphi panel estimates of health resource use. Univariate sensitivity analyses were made to evaluate uncertainties in parameters.

Results

The Delphi panel estimated that 20, 60 and 20 % of IPF patients presented with stable disease, slow and rapid disease progression, respectively. The estimated annual cost per patient with stable disease, slow and rapid disease progression was €11,484, €20,978 and €57,759, respectively. This corresponds to a weighted average annual cost of €26,435 with itemized costs of €1,184 (4.5), €7,147 (27.0), €5,950 (22.5), €11,666 (44.1) and €488 (1.9 %) for the diagnosis of IPF, treatment, monitoring, management of acute exacerbations and end-of-life care, respectively. The parameter that varied the annual cost per patient the most was resource use associated with acute exacerbations.

Conclusions

The management of patients with IPF in Spain, especially patients with rapid disease progression, has a high economic impact on the NHS.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-016-0168-6) contains supplementary material, which is available to authorized users.

Development of novel agents for idiopathic pulmonary fibrosis: progress in target selection and clinical trial design

Idiopathic pulmonary fibrosis (IPF) is a progressive, fatal disease. Until recently, the standard therapy for this disease has been essentially supportive, with the exception of a minority of patients who were eligible for lung transplantation. The development pathway for novel medications for IPF has been complicated. There have been several challenges, including an incomplete understanding of the pathogenesis, unpredictable clinical course, lack of validated biomarkers, the low clinical predictive value of animal models of lung injury, and the need to commit to large clinical trials of long duration to obtain initial evidence of clinical efficacy. Despite these challenges, the combination of recent advances in translational medicine and the unprecedented increase in clinical data accumulated from recent large clinical trials has stimulated an increase in the number of clinical development programs for IPF. Clinical programs are increasingly characterized by rational target selection, preclinical optimization of therapeutic molecules, and an emphasis on efficient clinical trial design. A lower rate of functional decline in patients treated with pirfenidone and nintedanib was demonstrated in large clinical trials. In October 2014, these two drugs became the first agents to be approved by the US Food and Drug Administration for the treatment of IPF. (Pirfenidone had already been approved in several countries outside the United States.) In November 2014, the European Medicines Agency approved the use of nintedanib for IPF. The landscape for management of IPF has markedly changed with the advent of approved therapeutic options for IPF. In this article, we review the strategies that are being used to increase the likelihood of success in clinical development programs of novel disease-modifying agents in IPF.

Statin Use Is Associated with Reduced Mortality in Patients with Interstitial Lung Disease

Introduction

We hypothesized that statin use begun before the diagnosis of interstitial lung disease is associated with reduced mortality.

Methods

We studied all patients diagnosed with interstitial lung disease in the entire Danish population from 1995 through 2009, comparing statin use versus no statin use in a nested 1:2 matched study.

Results

The cumulative survival as a function of follow-up time from the date of diagnosis of interstitial lung disease (n = 1,786+3,572) and idiopathic lung fibrosis (n = 261+522) was higher for statin users versus never users (log-rank: P = 7·10⁻⁹ and P = 0.05). The median survival time in patients with interstitial lung disease was 3.3 years in statin users and 2.1 years in never users. Corresponding values in patients with idiopathic lung fibrosis were 3.4 versus 2.4 years. After multivariable adjustment, the hazard ratio for all-cause mortality for statin users versus never users was 0.73 (95% confidence interval, 0.68 to 0.79) in patients with interstitial lung disease and 0.76 (0.62 to 0.93) in patients with idiopathic lung fibrosis. Results were robust in all sensitivity analyses.

Conclusion

Among patients with interstitial lung disease statin use was associated with reduced all-cause mortality.

Epigenetic targets for novel therapies of lung diseases

In spite of substantial advances in defining the immunobiology and function of structural cells in lung diseases there is still insufficient knowledge to develop fundamentally new classes of drugs to treat many lung diseases. For example, there is a compelling need for new therapeutic approaches to address severe persistent asthma that is insensitive to inhaled corticosteroids. Although the prevalence of steroid-resistant asthma is 5-10%, severe asthmatics require a disproportionate level of health care spending and constitute a majority of fatal asthma episodes. None of the established drug therapies including long-acting beta agonists or inhaled corticosteroids reverse established airway remodeling. Obstructive airways remodeling in patients with chronic obstructive pulmonary disease (COPD), restrictive remodeling in idiopathic pulmonary fibrosis (IPF) and occlusive vascular remodeling in pulmonary hypertension are similarly unresponsive to current drug therapy. Therefore, drugs are needed to achieve long-acting suppression and reversal of pathological airway and vascular remodeling. Novel drug classes are emerging from advances in epigenetics. Novel mechanisms are emerging by which cells adapt to environmental cues, which include changes in DNA methylation, histone modifications and regulation of transcription and translation by noncoding RNAs. In this review we will summarize current epigenetic approaches being applied to preclinical drug development addressing important therapeutic challenges in lung diseases. These challenges are being addressed by advances in lung delivery of oligonucleotides and small molecules that modify the histone code, DNA methylation patterns and miRNA function.

Hypoxia-sensitive pathways in inflammation-driven fibrosis

Tissue injury can occur for a variety of reasons, including physical damage, infection, and ischemia. The ability of tissues to effectively recover from injury is a cornerstone of human health. The healing response in tissues is conserved across organs and typically involves distinct but overlapping inflammatory, proliferative, and maturation/resolution phases. If the inflammatory phase is not successfully controlled and appropriately resolved, an excessive healing response characterized by scar formation can lead to tissue fibrosis, a major clinical complication in disorders such as Crohn's disease (CD). As a result of enhanced metabolic and inflammatory processes during chronic inflammation, profound changes in tissue oxygen levels occur leading to localized tissue hypoxia. Therefore, inflammation, fibrosis, and hypoxia are coincidental events during inflammation-driven fibrosis. Our current understanding of the mechanism(s) underpinning fibrosis is limited as are the therapeutic options available. In this review, we discuss what is known about the cellular and molecular mechanisms underpinning inflammation-driven fibrosis and how hypoxia may play a role in shaping this process.

Functional and structural impact of pirfenidone on the alterations of cardiac disease and diabetes mellitus

A synthetic compound, termed pirfenidone (PFD), is considered promising for the treatment of cardiac disease. It leads to beneficial effects in animal models of diabetes mellitus (DM); as well as in heart attack, atrial fibrillation, muscular dystrophy, and diabetic cardiomyopathy (DC). The latter is a result of alterations linked to metabolic syndrome as they promote cardiac hypertrophy, fibrosis and contractile dysfunction. Although reduced level of fibrosis and stiffness represent an essential step in the mechanism of PFD action, a wide range of functional effects might also contribute to the therapeutic benefits. For example, PFD stimulates L-type voltage-gated Ca(2+) channels (LTCCs), which are pivotal for a process known as excitation-contraction coupling (ECC). Recent evidence suggests that these two types of actions - namely structural and functional - aid in treating both cardiac disease and DM. This view is supported by the fact that in DC, for example, systolic dysfunction arises from both cardiac stiffness linked to fibrosis and down-regulation of ECC. Thus, not surprisingly, clinical trials have been conducted with PFD in the settings of DM, for treating not only cardiac but also renal disease. This review presents all these concepts, along with the possible mechanisms and pathophysiological consequences.

The inhibition effect and mechanism of SY0916 on pulmonary fibrosis

SY0916 is a new platelet-activating factor receptor antagonist developed by our institute. In this study, the inhibitory effect of SY0916 on pulmonary fibrosis was investigated in epithelial-mesenchymal transition (EMT) induced by transforming growth factor beta 1 (TGF-β1) in vitro and a pulmonary fibrosis animal model induced by bleomycin (BLM). The results showed that SY0916 could inhibit the EMT of A549 cells induced with TGF-β1. In vivo, SY0916 administration significantly ameliorated the BLM-mediated histological changes, reduced main biochemical parameters related to pulmonary fibrosis such as hydroxyproline and glutathione, and also notably attenuated the expression of key pro-fibrotic mediator, TGF-β1. These findings demonstrated that SY0916 could possibly be developed as a promising candidate for the treatment of pulmonary fibrosis.

Diagnosis and management of interstitial lung disease

The complex tasks of making a confident diagnosis of a specific form of interstitial lung disease (ILD) and formulating a patient-centered, personalized management plan in an attempt to achieve remission or stabilization of the disease process can pose formidable challenges to clinicians. When patients are evaluated for suspected ILD, an accurate diagnosis of the specific form of ILD that a patient has developed must be made to provide the patient with useful prognostic information and to formulate an appropriate management plan that can relieve symptoms and restore or significantly improve quality of life. A well-performed patient history and physical examination provides invaluable information that can be combined with appropriate laboratory testing, imaging, and, if needed, tissue biopsy to reach a confident ILD diagnosis, and high-resolution computed tomography (HRCT) of the thorax is usually a key component of the diagnostic evaluation. If treatment is indicated, many forms of ILD can respond significantly to immunosuppressive anti-inflammatory therapies. However, ILD accompanied by extensive fibrosis may be difficult to treat, and the identification of an effective pharmacologic therapy for idiopathic pulmonary fibrosis (IPF) has remained elusive despite the completion of many phase 3 clinical trials over the past decade. Nonetheless, patients with IPF or advanced forms of non-IPF ILD can benefit significantly from detection and treatment of various co-morbid conditions that are often found in patients (especially the elderly patient), and supportive care (oxygen therapy, pulmonary rehabilitation) can have a beneficial impact on quality of life and symptom palliation. Finally, lung transplantation is an option for patients with progressive, advanced disease that does not respond to other therapies, but only a relatively small subset of patients with end-stage ILD are able to meet wait listing requirements and eventually undergo successful lung transplantation.

Efficacy and safety of pirfenidone for idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a devastating chronic fibrotic lung disease. Although the precise cause of the disease is still unknown, recent studies have shown that the pathogenesis of pulmonary fibrosis involves multiple mechanisms, with abnormal behavior of alveolar epithelial cells considered a primary event. Pirfenidone is a multifunctional, orally available small molecule with anti-fibrotic, anti-inflammatory, and antioxidative activities, and has been shown to be a modulator of cytokines and growth factors, including TGF-β1, TNF-α, bFGF, IFN-γ, IL-1β, and IL-18 in animal models. Although its precise mechanism of action is not currently clear, pirfenidone is considered to exert inhibitory effects on multiple pathways involved in the pathogenesis of IPF. Two randomized placebo-controlled clinical trials in Japan demonstrated that pirfenidone significantly reduced the rate of decline of vital capacity in IPF patients. A Phase III study showed a significant increase in progression-free survival of patients in pirfenidone-treated groups compared to the placebo group. These results paved the way for the approval of pirfenidone for the treatment of IPF patients in Japan in 2008. The promising results of the Phase II study in Japan led to a larger international Phase III trial (CAPACITY). Subsequently, pirfenidone has also been approved in the European Union, South Korea, and Canada to date. Pirfenidone treatment is generally tolerated. Major adverse events are gastrointestinal symptoms, including decreased appetite, abdominal discomfort and nausea, photosensitivity, and fatigue, but many of these are mild and manageable. Clinical experience has shown that reduction in pirfenidone dose and the supportive use of gastrointestinal drugs are effective ways to manage these symptoms. Thus, pirfenidone treatment provides a means of intervention in the clinical course of IPF, and is a promising candidate for improving patient prognosis. For future development, it is important to establish the appropriate modality of treatment with pirfenidone and/or novel potential drugs.

Cellular mechanisms of tissue fibrosis. 6. Purinergic signaling and response in fibroblasts and tissue fibrosis

Tissue fibrosis occurs as a result of the dysregulation of extracellular matrix (ECM) synthesis. Tissue fibroblasts, resident cells responsible for the synthesis and turnover of ECM, are regulated via numerous hormonal and mechanical signals. The release of intracellular nucleotides and their resultant autocrine/paracrine signaling have been shown to play key roles in the homeostatic maintenance of tissue remodeling and in fibrotic response post-injury. Extracellular nucleotides signal through P2 nucleotide and P1 adenosine receptors to activate signaling networks that regulate the proliferation and activity of fibroblasts, which, in turn, influence tissue structure and pathologic remodeling. An important component in the signaling and functional responses of fibroblasts to extracellular ATP and adenosine is the expression and activity of ectonucleotideases that attenuate nucleotide-mediated signaling, and thereby integrate P2 receptor- and subsequent adenosine receptor-initiated responses. Results of studies of the mechanisms of cellular nucleotide release and the effects of this autocrine/paracrine signaling axis on fibroblast-to-myofibroblast conversion and the fibrotic phenotype have advanced understanding of tissue remodeling and fibrosis. This review summarizes recent findings related to purinergic signaling in the regulation of fibroblasts and the development of tissue fibrosis in the heart, lungs, liver, and kidney.

Existing and potential therapeutic uses for N-acetylcysteine: the need for conversion to intracellular glutathione for antioxidant benefits

N-acetyl-l-cysteine (NAC) has long been used therapeutically for the treatment of acetaminophen (paracetamol) overdose, acting as a precursor for the substrate (l-cysteine) in synthesis of hepatic glutathione (GSH) depleted through drug conjugation. Other therapeutic uses of NAC have also emerged, including the alleviation of clinical symptoms of cystic fibrosis through cysteine-mediated disruption of disulfide cross-bridges in the glycoprotein matrix in mucus. More recently, however, a wide range of clinical studies have reported on the use of NAC as an antioxidant, most notably in the protection against contrast-induced nephropathy and thrombosis. The results from these studies are conflicting and a consensus is yet to be reached regarding the merits or otherwise of NAC in the antioxidant setting. This review seeks to re-evaluate the mechanism of action of NAC as a precursor for GSH synthesis in the context of its activity as an "antioxidant". Results from recent studies are examined to establish whether the pre-requisites for effective NAC-induced antioxidant activity (i.e. GSH depletion and the presence of functional metabolic pathways for conversion of NAC to GSH) have received adequate consideration in the interpretation of the data. A key conclusion is a reinforcement of the concept that NAC should not be considered to be a powerful antioxidant in its own right: its strength is the targeted replenishment of GSH in deficient cells and it is likely to be ineffective in cells replete in GSH.