Pirfenidone induces intercellular adhesion molecule-1 (ICAM-1) down-regulation on cultured human synovial fibroblasts

New Antifibroblastic Medication in Dermatology: Could Nintedanib Treat Scarring?

There are a wide variety of disfiguring dermatological conditions whose pathologic substrate is represented by the unwanted deposition of collagen from dermal fibroblasts. Pirfenidone has demonstrated efficiency in the treatment of disordered collagen production when applied topically. Due to a similar mechanism of action, we also hypothesize that a similar medication, nintedanib, might have similar applications. We also propose that a liposomal technology may assist in the penetration of nintedanib and enhance its clinical effects.

Tumor Microenvironment Features and Chemoresistance in Pancreatic Ductal Adenocarcinoma: Insights into Targeting Physicochemical Barriers and Metabolism as Therapeutic Approaches

Currently, the median overall survival of PDAC patients rarely exceeds 1 year and has an overall 5-year survival rate of about 9%. These numbers are anticipated to worsen in the future due to the lack of understanding of the factors involved in its strong chemoresistance. Chemotherapy remains the only treatment option for most PDAC patients; however, the available therapeutic strategies are insufficient. The factors involved in chemoresistance include the development of a desmoplastic stroma which reprograms cellular metabolism, and both contribute to an impaired response to therapy. PDAC stroma is composed of immune cells, endothelial cells, and cancer-associated fibroblasts embedded in a prominent, dense extracellular matrix associated with areas of hypoxia and acidic extracellular pH. While multiple gene mutations are involved in PDAC initiation, this desmoplastic stroma plays an important role in driving progression, metastasis, and chemoresistance. Elucidating the mechanisms underlying PDAC resistance are a prerequisite for designing novel approaches to increase patient survival. In this review, we provide an overview of the stromal features and how they contribute to the chemoresistance in PDAC treatment. By highlighting new paradigms in the role of the stromal compartment in PDAC therapy, we hope to stimulate new concepts aimed at improving patient outcomes.

Targeting the Stromal Pro-Tumoral Hyaluronan-CD44 Pathway in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest malignancies. Present-day treatments have not shown real improvements in reducing the high mortality rate and the short survival of the disease. The average survival is less than 5% after 5 years. New innovative treatments are necessary to curtail the situation. The very dense pancreatic cancer stroma is a barrier that impedes the access of chemotherapeutic drugs and at the same time establishes a pro-proliferative symbiosis with the tumor, thus targeting the stroma has been suggested by many authors. No ideal drug or drug combination for this targeting has been found as yet. With this goal in mind, here we have explored a different complementary treatment based on abundant previous publications on repurposed drugs. The cell surface protein CD44 is the main receptor for hyaluronan binding. Many malignant tumors show over-expression/over-activity of both. This is particularly significant in pancreatic cancer. The independent inhibition of hyaluronan-producing cells, hyaluronan synthesis, and/or CD44 expression, has been found to decrease the tumor cell's proliferation, motility, invasion, and metastatic abilities. Targeting the hyaluronan-CD44 pathway seems to have been bypassed by conventional mainstream oncological practice. There are existing drugs that decrease the activity/expression of hyaluronan and CD44: 4-methylumbelliferone and bromelain respectively. Some drugs inhibit hyaluronan-producing cells such as pirfenidone. The association of these three drugs has never been tested either in the laboratory or in the clinical setting. We present a hypothesis, sustained by hard experimental evidence, suggesting that the simultaneous use of these nontoxic drugs can achieve synergistic or added effects in reducing invasion and metastatic potential, in PDAC. A non-toxic, low-cost scheme for inhibiting this pathway may offer an additional weapon for treating pancreatic cancer.

Pirfenidone: Molecular Mechanisms and Potential Clinical Applications in Lung Disease

Pirfenidone (PFD) is a pharmacological compound with therapeutic efficacy in idiopathic pulmonary fibrosis. It has been chiefly characterized as an antifibrotic agent, although it was initially developed as an antiinflammatory compound because of its ability to diminish the accumulation of inflammatory cells and cytokines. Despite recent studies that have elucidated key mechanisms, the precise molecular activities of PFD remain incompletely understood. PFD modulates fibrogenic growth factors, thereby attenuating fibroblast proliferation, myofibroblast differentiation, collagen and fibronectin synthesis, and deposition of extracellular matrix. This effect is mediated by suppression of TGF-β1 (transforming growth factor-β1) and other growth factors. Here, we appraise the impact of PFD on TGF-β1 production and its downstream pathways. Accumulating evidence indicates that PFD also downregulates inflammatory pathways and therefore has considerable potential as a viable and innovative antiinflammatory compound. We examine the effects of PFD on inflammatory cells and the production of pro- and antiinflammatory cytokines in the lung. In this context, recent evidence that PFD can target inflammasome pathways and ensuing lung inflammation is highlighted. Finally, the antioxidant properties of PFD, such as its ability to inhibit redox reactions and regulate oxidative stress-related genes and enzymes, are detailed. In summary, this narrative review examines molecular mechanisms underpinning PFD and its recognized benefits in lung fibrosis. We highlight preclinical data that demonstrate the potential of PFD as a nonsteroidal antiinflammatory agent and outline areas for future research.

Inhibitors of the Autotaxin-Lysophosphatidic Acid Axis and Their Potential in the Treatment of Interstitial Lung Disease: Current Perspectives

Idiopathic pulmonary fibrosis is a progressive fibrosing interstitial lung disease for which there is no known cure. Currently available therapeutic options have been shown at best to slow the progression of the disease and thus there remains an urgent unmet need to identify new therapies. In this article, we will discuss the mechanisms of action, pre-clinical and clinical trial data surrounding inhibitors of the autotaxin-lysophosphatidic acid axis, which show promise as emerging novel therapies for fibrotic lung disease.

Idiopathic Pulmonary Fibrosis: A Review of Disease, Pharmacological, and Nonpharmacological Strategies With a Focus on Symptoms, Function, and Health-Related Quality of Life

Despite several advances in treatment, idiopathic pulmonary fibrosis (IPF) remains a progressive, symptomatic, and terminal disease in patients not suitable for lung transplantation. With disease progression, IPF often leads to a constellation of symptoms, including dyspnea, cough, anxiety, and depression. Palliative care is appropriate to support these patients. However, traditional curriculum in palliative care has often focused on supporting patients with malignant disease, and clinicians are not universally trained to manage patients with progressive nonmalignant diseases such as IPF. Current antifibrotic therapies aim to slow disease progression but are not able to reduce symptoms or improve daily function and health-related quality of life (HRQL). Palliative care in this patient group requires an understanding of the clinical characteristics of IPF, comorbidities, common medications used, and nonpharmacological strategies that can be undertaken to improve daily function and HRQL. This review focuses on IPF management strategies and their effects on symptoms, exercise tolerance, HRQL, and survival. Pharmacological interactions and considerations related to commonly used palliative care medications are also reviewed. This review highlights the needs of patients with IPF and caregivers, psychosocial function, patient-reported assessment tools, and topics related to advance care planning.

Pirfenidone in Heart Failure with Preserved Ejection Fraction-Rationale and Design of the PIROUETTE Trial

BACKGROUND

The PIROUETTE (PIRfenidOne in patients with heart failUre and preserved lEfT venTricular Ejection fraction) trial is designed to evaluate the efficacy and safety of the anti-fibrotic pirfenidone in patients with chronic heart failure and preserved ejection fraction (HFpEF) and myocardial fibrosis. HFpEF is a diverse syndrome associated with substantial morbidity and mortality. Myocardial fibrosis is a key pathophysiological mechanism of HFpEF and myocardial fibrotic burden is strongly and independently associated with adverse outcome. Pirfenidone is an oral anti-fibrotic agent, without haemodynamic effect, that leads to regression of myocardial fibrosis in preclinical models. It has proven clinical effectiveness in pulmonary fibrosis.

METHODS

The PIROUETTE trial is a randomised, double-blind, placebo-controlled phase II trial evaluating the efficacy and safety of 52 weeks of treatment with pirfenidone in patients with chronic HFpEF (symptoms and signs of heart failure, left ventricular ejection fraction ≥ 45%, elevated natriuretic peptides [BNP ≥ 100 pg/ml or NT-proBNP ≥ 300 pg/ml; or BNP ≥ 300 pg/ml or NT-proBNP ≥ 900 pg/ml if in atrial fibrillation]) and myocardial fibrosis (extracellular matrix (ECM) volume ≥ 27% measured using cardiovascular magnetic resonance). The primary outcome measure is change in myocardial ECM volume. A sub-study will investigate the relationship between myocardial fibrosis and myocardial energetics, and the impact of pirfenidone, using ³¹phosphorus magnetic resonance spectroscopy.

DISCUSSION

PIROUETTE will determine whether pirfenidone is superior to placebo in relation to regression of myocardial fibrosis and improvement in myocardial energetics in patients with HFpEF and myocardial fibrosis (NCT02932566).

CLINICAL TRIAL REGISTRATION

clinicaltrials.gov (NCT02932566) https://clinicaltrials.gov/ct2/show/NCT02932566.

Effect of pirfenidone injection on ferret vocal fold scars: A preliminary in vivo study

OBJECTIVES

This study examined the antifibrotic effect of pirfenidone (PFD), which has received regulatory approval in the United States and Japan for treatment of idiopathic pulmonary fibrosis, on the scarred ferret vocal fold (VF) in vivo.

METHODS

Eight male ferrets were divided into two groups: saline and PFD. All animals underwent unilateral scarring under anesthesia. The right VF was electrocauterized with ablation of the entire lamina propria. PFD (1.0 mg/mL) or saline injections into right-side scarred VFs were performed (under an operating microscope) 4 weeks later. After an additional 4 weeks, the larynges were harvested for histological analysis. Prior to harvesting, the ferrets were re-anesthetized, and the VFs were observed and recorded using a rigid video laryngoscope. We immunohistochemically evaluated the expression of collagen types I and III, alpha-smooth muscle actin (α-SMA), and fibronectin in the entire lamina propria. We compared the affected areas (calculated using ImageJ software) between the treated (right) and untreated (left) sides within the same animals and between groups.

RESULTS

Collagen type I (P = 0.0021) and α-SMA (P = 0.0021) expression levels were lower in the PFD group, but the collagen type III and fibronectin levels did not differ significantly between the two groups.

CONCLUSION

PFD injection into the scarred VF is a potentially promising novel antifibrotic treatment.

LEVEL OF EVIDENCE

NA Laryngoscope, 130:726-731, 2020.

Pathophysiology of Fibrosis in the Vocal Fold: Current Research, Future Treatment Strategies, and Obstacles to Restoring Vocal Fold Pliability

Communication by voice depends on symmetrical vibrations within the vocal folds (VFs) and is indispensable for various occupations. VF scarring is one of the main reasons for permanent dysphonia and results from injury to the unique layered structure of the VFs. The increased collagen and decreased hyaluronic acid within VF scars lead to a loss of pliability of the VFs and significantly decreases their capacity to vibrate. As there is currently no definitive treatment for VF scarring, regenerative medicine and tissue engineering have become increasingly important research areas within otolaryngology. Several recent reviews have described the problem of VF scarring and various possible solutions, including tissue engineered cells and tissues, biomaterial implants, stem cells, growth factors, anti-inflammatory cytokines antifibrotic agents. Despite considerable research progress, these technical advances have not been established as routine clinical procedures. This review focuses on emerging techniques for restoring VF pliability using various approaches. We discuss our studies on interactions among adipose-derived stem/stromal cells, antifibrotic agents, and VF fibroblasts using an in vitro model. We also identify some obstacles to advances in research.

South-West of England's Experience of the Safety and Tolerability Pirfenidone and Nintedanib for the Treatment of Idiopathic Pulmonary Fibrosis (IPF)

Purpose: Pirfenidone and nintedanib are two novel antifibrotic agents licensed for the treatment IPF. Prior to being approved for use in England for patients with FVC >50% and <80%, these were made available for all IPF patients under the Mild Patient Program (MPP) and Patient In Need Scheme (PIN). Prescribing of these medications is restricted to specialist centers. We sought to characterize the population of patients prescribed antifibrotics and determine the drug tolerability of these medications in the Northern hub of the Southwest of England regional ILD network. Methods: A retrospective analysis of all patients treated with antifibrotics between August 2012 and July 2017 was undertaken. Baseline characteristics including patient demographics and pulmonary physiology, in addition to drug tolerability and reasons for treatment cessation were collated. Data were compared using unpaired student's t-test, Chi-squared, Mann-Whitney rank sum or ANOVA as appropriate. Logistic regression analysis evaluated clinical characteristics associated with discontinuation of pirfenidone therapy. P < 0.05 was considered statistically significant. Findings: A total of 164 patients, all with consensus diagnoses of IPF, were identified. Of these, 70.1% (115/164) received pirfenidone as their initial therapy. Baseline age, gender and pulmonary physiology did not differ significantly between groups. Drug discontinuation occurred most commonly due to adverse drug reactions events (ADRs) for both pirfenidone [40.0% (46/115)] and nintedanib [16.3% (8/49)]. Anorexia, rash and gastrointestinal disturbance were reported most commonly as the reason for cessation of pirfenidone; anorexia, nausea and weight loss for nintedanib. Duration of therapy prior to discontinuation because of ADRs did not differ significantly between medication groups but patients with a baseline FVC < 65% predicted, had a significantly shorter duration of pirfenidone prior to discontinuation due to ADRs, compared to those with a FVC 65-80% predicted. Multivariate logistic regression did not identify any independent baseline characteristics that predicted discontinuation of pirfenidone therapy prior to 52 weeks. Implications: Idiopathic pulmonary fibrosis (IPF) patients treated with nintedanib had comparable treatment emergent adverse event (TEAE) profiles in clinical practice to those reported in clinical trials. The TEAE profile of pirfenidone was higher than clinical trial data would suggest, although comparable to real-world datasets. Further work is required to explore the possible reasons underpinning this finding, including whether this is related to population co-morbidities or center threshold. No new safety concerns were identified.

The antifibrotic drug pirfenidone inhibits spondyloarthritis fibroblast-like synoviocytes and osteoblasts in vitro

Background

The pathogenesis of spondyloarthritis (SpA) involves both inflammation and new bone formation in the spine. In line with this, the disease has been characterized as both inflammatory and fibrotic. The current treatment dampens inflammation while new bone formation can progress. Therefore, there is an unmet therapeutic need for the treatment of new bone formation in SpA. Fibrosis is mediated by myofibroblasts and new bone formation is the result of increased osteoblast mineralization and decreased osteoclast resorption. Here, we evaluate the potential effect of the newly approved anti-fibrotic agent pirfenidone (PFD) on fibrosis and new bone formation in cell culture models of SpA.

Methods

Fibroblast-like synoviocytes (FLSs) were isolated from SpA patients (n = 6) while the osteoblast cell line Saos-2 was purchased. The cells were cultured with PFD at 0.25 0.5, or 1.0 mg/ml. The proliferation of FLSs was analyzed with light microscopy and flow cytometry. The differentiation and activation of FLSs was assessed with flow cytometry, a membrane-based antibody array and enzyme-linked immunosorbant assays. The mineralization capacity of osteoblasts was studied with an assay measuring deposition of hydroxyapatite.

Results

PFD reduced the Ki67 expression 7.1-fold in untreated FLSs (p = 0.001) and 11.0-fold in FLSs stimulated with transforming growth factor beta (TGFβ), tumor necrosis factor alpha (TNFα), and interferon gamma (IFNγ) (p = 0.022). There were no statistically significant changes in membrane expression of alpha smooth muscle actin (αSMA), intercellular adhesion molecule 1 (ICAM-1), or human leukocyte antigen DR (HLA-DR). In supernatants from FLSs stimulated with TGFβ, TNFα, and IFNγ, PFD decreased the secretion of 3 of 12 proteins more than 2-fold in the membrane-based antibody array. The changes in secretion of monocyte chemoattractant protein 1 (MCP-1) and chitinase-3-like protein 1 (CHI3L1, YKL-40) were validated with ELISA. PFD decreased the secretion of both Dickkopf-related protein 1 (DKK1) (p = 0.006) and osteoprotegerin (OPG) (p = 0.02) by SpA FLSs stimulated with TGFβ, TNFα, and IFNγ. Finally, PFD inhibited the deposition of hydroxyapatite by osteoblasts in a dose-dependent manner (p = 0.0001).

Conclusions

PFD inhibited SpA FLS proliferation and function and osteoblast mineralization in vitro. This encourages studies of the in vivo effect of PFD in SpA.

Idiopathic Pulmonary Fibrosis (IPF): An Overview

Idiopathic pulmonary fibrosis (IPF) is an interstitial lung disease characterised by chronic, progressive scarring of the lungs and the pathological hallmark of usual interstitial pneumonia. Current paradigms suggest alveolar epithelial cell damage is a key initiating factor. Globally, incidence of the disease is rising, with associated high morbidity, mortality, and economic healthcare burden. Diagnosis relies on a multidisciplinary team approach with exclusion of other causes of interstitial lung disease. Over recent years, two novel antifibrotic therapies, pirfenidone and nintedanib, have been developed, providing treatment options for many patients with IPF, with several other agents in early clinical trials. Current efforts are directed at identifying key biomarkers that may direct more customized patient-centred healthcare to improve outcomes for these patients in the future.

Systemic sclerosis phase III clinical trials: Hope on the horizon?

While significant progress has been made in treating systemic sclerosis, many patients still have an outcome that is far from satisfactory. For the first time in history, several drugs are now in phase III randomized controlled trials. Approaches tested include the anti-B cell antibody rituximab, the anti-interleukin-6 receptor antibody tocilizumab, the antifibrotic drugs nintedanib and pirfenidone, and the cannabinoid receptor mimetic lenabasum. That all these drugs are in advanced clinical trials despite the relatively low incidence of the disease therefore is good news. Not only is there realistic hope that at least some of the approaches will work, this also indicates growing industry interest, for most of the trials are company-sponsored. This review attempts to delineate the ongoing trials and to summarize the underlying evidence of these candidate systemic sclerosis drugs.

Potential treatment for vocal fold scar with pirfenidone

OBJECTIVES/HYPOTHESIS

Pirfenidone (PFD) is a strong antifibrotic agent that has been clinically approved in Japan for idiopathic pulmonary fibrosis. We examined the antifibrotic effects of PFD on fibroblasts isolated from scarred vocal folds (VFs) of ferrets in vitro.

STUDY DESIGN

Prospective animal experiments with controls.

METHODS

Scar fibroblasts (SFs) were isolated from scarred VFs that had been electrocauterized 2 weeks before harvesting (N = 4). Normal fibroblasts (NFs) were isolated from intact VFs (N = 4). SFs and NFs were incubated in the presence of 10 ng/mL transforming growth factor β1 (TGF-β1), with or without PFD. After the 48-hour incubation, mRNA expression levels of α smooth muscle actin (αSMA), TGF-β1, collagen type I, and hyaluronan synthase 2 (HAS2) were examined by real-time polymerase chain reaction. Immunohistochemistry with anti-αSMA anti-collagen type I and phosphorylated Smad (p-Smad)2/3 antibodies in SFs with or without PFD was performed. SFs and NFs were cultured in collagen gel with or without PFD for 48 hours, and the extent of gel contraction was examined quantitatively.

RESULTS

PFD treatment significantly (P < .05) decreased mRNA expression of collagen type I, significantly increased mRNA expression of TGF-β1 and HAS2, and significantly suppressed collagen gel contraction. However, it did not have a significant effect on the expression of αSMA. The expression of p-Smad2/3 in the nucleus was faded with PFD, possibly demonstrating the suppression of translocation of p-Smad2/3 from cytoplasm to nucleus with PFD.

CONCLUSIONS

This is the first report to demonstrate the in vitro antifibrotic effects of PFD on fibroblasts isolated from scarred VFs of ferrets.

LEVEL OF EVIDENCE

NA. Laryngoscope, 128:E171-E177, 2018.

Pirfenidone for primary Sjögren's syndrome-related fibrotic interstitial pneumonia

Primary Sjögren's syndrome-related interstitial pneumonia (pSS-IP) is occasionally progressive even with immunosuppressive therapy and new treatment options are warranted. A 42-year-old woman was diagnosed with pSS-IP with pathological usual interstitial pneumonia pattern. Although her forced vital capacity (FVC) had temporarily improved after prednisolone therapy, it deteriorated during the prednisolone tapering off period. Therefore, pirfenidone was added in conjunction with prednisolone. During the 12-month treatment period, her FVC was almost stable. A 62-year-old man, a current heavy smoker, was diagnosed with pSS-IP. Chest computed tomography showed bilateral honeycombing with ground-glass attenuation on a background of emphysema. He gradually developed dyspnea on exertion and his FVC deteriorated. Hence, pirfenidone was administered as a monotherapy. Six months later, his FVC and exercise tolerance had significantly improved. Pirfenidone might have a role for the treatment of pSS-IP. (Sarcoidosis Vasc Diffuse Lung Dis 2017; 34: 91-96).

Pirfenidone for the treatment of idiopathic pulmonary fibrosis

INTRODUCTION

Idiopathic pulmonary fibrosis (IPF) is a diffuse parenchymal lung disease with no cure. Up until recently, no treatment had been proven to alter its natural history as judged by rate of lung function decline. In 2014 however, the emergence of two novel anti-fibrotic agents, Pirfenidone and Nintedanib revolutionized the management of this condition. Both have demonstrated the ability to deliver a major reduction in the rate of chronic IPF progression. Areas Covered: This review article focuses on Pirfenidone - a pyridone derivative initially designed as an analgesic and anti-pyretic agent. Here we describe the history of the drug from its inception through to exploratory pre-clinical in-vitro and in-vivo studies where its anti-fibrotic potential was identified, and eventually to large multicenter randomized controlled trials. Expert Commentary: This article also summarizes some of the difficulties surrounding clinical end-point selection in IPF trials and addresses some of the challenges facing the IPF community over the coming years.

Sequential Release of Multiple Drugs from Flexible Drug Delivery Films

Sequential release of drugs aligned with the phases of tissue healing could reduce scarring. To achieve this aim, layered film devices comprising cellulose acetate phthalate (CAP) and Pluronic F-127 (Pluronic) were loaded with ketoprofen, quercetin, and pirfenidone. Citrate plasticizers were added to impart flexibility. Release of two or three drugs in sequence over several days was obtained for all multilayered devices tested. Mechanical analysis showed that elongation increased and modulus decreased with increasing plasticizer content. Release profiles can be tailored by order of layers, plasticizer concentration, and drug loaded, making CAP-Pluronic an appealing system for inhibiting scar tissue formation.

Combined Effects of Drugs and Plasticizers on the Properties of Drug Delivery Films

Formation of scar tissue may be reduced or prevented if wounds were locally treated with a combination of molecules tuned to the different healing phases, guiding tissue regeneration along a scar free path. To this end, drug delivery devices made of cellulose acetate phthalate and Pluronic F-127 were loaded with either quercetin or pirfenidone and plasticized with either triethyl citrate (TEC) or tributyl citrate (TBC). Quercetin inhibits oxidative stress, and pirfenidone has been shown to reduce production of pro-inflammatory and fibrogenic molecules. The combined effects of drug and plasticizer on erosion, release, and mechanical properties of the drug delivery films were investigated. TEC-plasticized films containing quercetin released drug at a slower rate than did TBC films. Pirfenidone-loaded films released drug at a faster rate than erosion occurred for both types of plasticizers. Higher plasticizer contents of both TEC and TBC increased the elongation and decreased the elastic modulus. In contrast, increased pirfenidone loading in both TEC and TBC films resulted in a significantly higher modulus, an anti-plasticizer effect. Adding pirfenidone significantly decreased elongation for all film types, but quercetin-loaded samples had significantly greater elongation with increasing drug content. Films containing quercetin elongated more than did pirfenidone-loaded films. Quercetin is over 1.5 times larger than pirfenidone, has water solubility over 12 times lower, and has 6 times more bonding sites than pirfenidone. These differences affected how the two drugs interacted with cellulose acetate phthalate and Pluronic F-127 and thereby determined polymer properties. Drug release, erosion, and mechanical properties of association polymer films can be tailored by the characteristics of the drugs and plasticizers included in the system.

Pirfenidone Initiates a New Era in the Treatment of Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and fatal disease that has long eluded therapy. Prognosis remains very poor, and currently lung transplantation offers the only hope of survival. Recently, great strides have been made in the development of pharmaceutical therapy to treat IPF. Pirfenidone, an oral antifibrotic agent, has been shown to slow progression of the disease and improve progression-free survival, offering new hope for patients suffering from IPF.

Pirfenidone for Idiopathic Pulmonary Fibrosis: A Systematic Review and Meta-Analysis

Idiopathic pulmonary fibrosis (IPF) is a progressive disease with poor prognosis. In the last decades pirfenidone an anti-inflammatory and anti-fibrotic agent has shown benefit in inhibit collagen production and has also demonstrated benefit in decline progression in IPF in physiological outcomes as Forced vital capacity (FVC), in clinical outcomes such as progression free survival (PFS) and a benefit in mortality but no in clinically relevant outcomes as exacerbations or worsening of IPF. Methods: We conducted a systematic review to evaluate the effectiveness of physiological and clinical outcomes of pirfenidone compared to placebo in IPF. We performed a search with no language restriction. Two researchers performed literature search, quality assessment, data extraction and analysis. And was performed a summary of findings table following the GRADE approach. Results: We included 5 RCTs (Randomized controlled trials) in analysis. The meta-analysis resulted in a decrease in all cause-mortality (RR 0.52 IC 0.32–0.88) and IPF related mortality (RR 0.32 IC 0.14–0.75); other outcomes evaluated were worsening of IPF (RR 0.64 IC 0.50–0.83) and acute exacerbation (RR: 0.72 IC 0.30–1.66 respectively). Also there was a decrease in progression free survival (PFS) (RR 0.83 IC 0.74–0.92) compared to placebo. Conclusions: We observed significant differences in physiologic and clinically relevant outcomes such as reduction in all-cause mortality, IPF related mortality, worsening and exacerbation of IPF and PFS. So pirfenidone treatment should be considered not only for its benefits in pulmonary function tests but also by its clinically relevant outcomes.

Effect of pirfenidone on proliferation, TGF-β-induced myofibroblast differentiation and fibrogenic activity of primary human lung fibroblasts

Pirfenidone is an orally active small molecule that has been shown to inhibit the progression of fibrosis in animal models and in patients with idiopathic pulmonary fibrosis. Although pirfenidone exhibits well documented antifibrotic and antiinflammatory activities, in vitro and in vivo, its molecular targets and mechanisms of action have not been elucidated. In this study, we investigated the effects of pirfenidone on proliferation, TGF-β-induced differentiation and fibrogenic activity of primary human lung fibroblasts (HLFs). Pirfenidone reduced fibroblast proliferation and attenuated TGF-β-induced α-smooth muscle actin (SMA) and pro-collagen (Col)-I mRNA and protein levels. Importantly, pirfenidone inhibited TGF-β-induced phosphorylation of Smad3, p38, and Akt, key factors in the TGF-β pathway. Together, these results demonstrate that pirfenidone modulates HLF proliferation and TGF-β-mediated differentiation into myofibroblasts by attenuating key TGF-β-induced signaling pathways.

No effect of pirfenidone treatment in fulminant bleomycin-induced pneumonitis

Bleomycin-induced pneumonitis (BIP) is a serious and potentially fatal adverse effect of bleomycin. Currently, BIP is treated on an empirical basis with high dose steroid. Pirfenidone is a new antifibrotic drug, which has been proven beneficial in idiopathic pulmonary fibrosis and is able to inhibit or reverse BIP in animal models. Here, the first two cases of human BIP treated with pirfenidone in addition to steroid therapy are presented. Unfortunately, both patients died, which may be explained by the initiation of therapy at a late stage. Therefore, studies of early or prophylactic treatment with pirfenidone in relation to bleomycin-containing chemotherapy regimens are needed.

Pirfenidone: in idiopathic pulmonary fibrosis

Pirfenidone is an orally administered pyridine that has orphan designation for the treatment of mild to moderate idiopathic pulmonary fibrosis (IPF) in the EU. Pirfenidone 2403 mg/day for 72 weeks administered to patients with IPF was associated with a significantly lower mean decline in the percent predicted forced vital capacity than placebo (primary endpoint) according to data from one of two randomized, double-blind, multinational trials (studies 004 and 006 [also known as the CAPACITY trials]), and data from a pooled analysis of both trials. In another randomized, double-blind, multicentre Japanese trial, the adjusted mean in the change in vital capacity from baseline to week 52 was significantly lower in patients with IPF who received pirfenidone 1800 mg/day (considered to be comparable to the 2403 mg/day dose in studies 004 and 006 on a weight-normalized basis) than in those who received placebo (primary endpoint). Pirfenidone had an acceptable tolerability profile in clinical trials, with most adverse events being mild to moderate in severity.

In vitro effects of pirfenidone on cardiac fibroblasts: proliferation, myofibroblast differentiation, migration and cytokine secretion

Cardiac fibroblasts (CFs) are the primary cell type responsible for cardiac fibrosis during pathological myocardial remodeling. Several studies have illustrated that pirfenidone (5-methyl-1-phenyl-2-[1H]-pyridone) attenuates cardiac fibrosis in different animal models. However, the effects of pirfenidone on cardiac fibroblast behavior have not been examined. In this study, we investigated whether pirfenidone directly modulates cardiac fibroblast behavior that is important in myocardial remodeling such as proliferation, myofibroblast differentiation, migration and cytokine secretion. Fibroblasts were isolated from neonatal rat hearts and bioassays were performed to determine the effects of pirfenidone on fibroblast function. We demonstrated that treatment of CFs with pirfenidone resulted in decreased proliferation, and attenuated fibroblast α-smooth muscle actin expression and collagen contractility. Boyden chamber assay illustrated that pirfenidone inhibited fibroblast migration ability, probably by decreasing the ratio of matrix metalloproteinase-9 to tissue inhibitor of metalloproteinase-1. Furthermore, pirfenidone attenuated the synthesis and secretion of transforming growth factor-β1 but elevated that of interleukin-10. These direct and pleiotropic effects of pirfenidone on cardiac fibroblasts point to its potential use in the treatment of adverse myocardial remodeling.

Pirfenidone treatment of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a discrete clinicopathologic entity defined by the presence of usual interstitial pneumonia on high-resolution CT scan and/or open lung biopsy and the absence of an alternate diagnosis or exposure explaining these findings. There are currently no FDA-approved therapies available to treat this disease, and the 5-year mortality is ∼80%. The pyridone derivative pirfenidone has been studied extensively as a possible therapeutic agent for use in this deadly disease. This review will present the unique clinical features and management issues encountered by physicians caring for IPF patients, including the poor response to conventional therapy. The biochemistry and preclinical efficacy of pirfenidone will be discussed along with a comprehensive review of the clinical efficacy, safety, and side effects and patient-centered foci such as quality of life and tolerability. It is hoped that this information will lend insight into the complex issues surrounding the use of pirfenidone in IPF and lead to further investigation of this agent as a possible therapy in this devastating disease.

Novel systems biology insights using antifibrotic approaches for diabetic kidney disease

Although several interventions slow the progression of diabetic nephropathy, current therapies do not halt progression completely. Recent preclinical studies suggested that pirfenidone (PFD) prevents fibrosis in various diseases, but the mechanisms underlying its antifibrotic action are incompletely understood. To explore the therapeutic potential of PFD, we studied the PFD-treated db/db diabetic mouse kidney by liquid chromatography-tandem mass spectrometry proteomics. A total of 21 proteins unique to PFD-treated diabetic kidneys were identified. Analysis of gene ontology and protein-protein interactions of these proteins suggested that PFD may regulate RNA translation. Two key proteins involved in mRNA translation initiation and elongation were further evaluated and found to be regulated by PFD at the level of phosphorylation. In conclusion, insights from combining proteomics and bioinformatics improve the likelihood of rapid advancement of novel clinical therapies focused on reducing inflammation and fibrosis for diabetic complications.

Pirfenidone inhibits T-cell activation, proliferation, cytokine and chemokine production, and host alloresponses

BACKGROUND

We previously showed that pirfenidone, an anti-fibrotic agent, reduces lung allograft injury or rejection. In this study, we tested the hypothesis that pirfenidone has immune modulating activities and evaluated its effects on the function of T-cell subsets, which play important roles in allograft rejection.

METHOD

We first evaluated whether pirfenidone alters T-cell proliferation and cytokine release in response to T-cell receptor (TCR) activation, and whether pirfenidone alters regulatory T cells (CD4CD25) suppressive effects using an in vitro assay. Additionally, pirfenidone effects on alloantigen-induced T-cell proliferation in vivo were assessed by adoptive transfer of carboxyfluorescein diacetate succinimidyl ester-labeled T cells across a parent->F1 major histocompatibility complex mismatch, as well as using a murine heterotopic cardiac allograft model (BALB/c->C57BL/6).

RESULTS

Pirfenidone was found to inhibit the responder frequency of TCR-stimulated CD4 cell total proliferation in vitro and in vivo, whereas both CD4 and CD8 proliferation index were reduced by pirfenidone. Additionally, pirfenidone inhibited TCR-induced production of multiple pro-inflammatory cytokines and chemokines. Interestingly, there was no change on transforming growth factor-beta production by purified T cells, and pirfenidone had no effect on the suppressive properties of naturally occurring regulatory T cells. Pirfenidone alone showed a small but significant (P<0.05) effect on the in vivo allogeneic response, whereas the combination of pirfenidone and low dose rapamycin had more remarkable effect in reducing the alloantigen response with prolonged graft survival.

CONCLUSION

Pirfenidone may be an important new agent in transplantation, with particular relevance to combating chronic rejection by inhibiting both fibroproliferative and alloimmune responses.

Amelioration of lacrimal gland inflammation by oral administration of K-13182 in Sjögren's syndrome model mice

Regulation of the adhesion of mononuclear cells to endothelial cells is considered to be a critical step for the treatment of inflammatory diseases, including autoimmune diseases. K-13182 was identified as a novel inhibitor for these adhesions. K-13182 inhibited the expression of vascular cell adhesion molecule-1 (VCAM-1, CD106) on human umbilical vein endothelial cells (HUVECs) and on mouse vascular endothelial cell line (MAECs) induced by tumour necrosis factor (TNF)-alpha. K-13182 also inhibited the adhesion of mononuclear cells to these HUVECs and MAECs, indicating that K-13182 suppressed these adhesions mediated by cellular adhesion molecules including VCAM-1. To evaluate the therapeutic effect in autoimmune disease model mice, K-13182 was orally administered to non-obese diabetic (NOD) mice as Sjögren's syndrome (SS) model mice. Severe destructive inflammatory lesions were observed in the lacrimal glands of vehicle-treated control mice; however, 8-week administration of K-13182 inhibited the mononuclear cell infiltration into the inflammatory lesions of the lacrimal glands. In K-13182-treated mice, the decrease in tear secretion was also prevented compared to the control mice. In addition, the apoptosis and the expression of FasL (CD178), perforin, and granzyme A was suppressed in the lacrimal glands of K-13182-treated mice. Therefore, K-13182 demonstrated the possibility of therapeutic efficacy for the inflammatory region of autoimmune disease model mice. These data reveal that VCAM-1 is a promising target molecule for the treatment of autoimmune diseases as a therapeutic strategy and that K-13182 has the potential as a new anti-inflammatory drug for SS.

Oral pirfenidone in patients with chronic fibrosis resulting from radiotherapy: a pilot study

BACKGROUND

Fibrosis is a common side effect after treatment with ionizing radiation. Several methods to ameliorate debilitating fibrosis have been employed but without consistent results. The goal of this pilot study is to determine if Pirfenidone, a novel regulator of cytokine gene expression, has the potential to ameliorate established radiation-induced fibrosis.

METHODS

Open label, prospective pilot study of 800 mg three times/day, orally administered Pirfenidone was administered to enrolled patients who were had completed radiation therapy and who had established radiation-induced fibrosis. Range of motion (ROM) was assessed using standard measures, and subjective measures of pain, fatigue, disability and global health were measured every three months.

RESULTS

Seven patients were enrolled of whom 3 had ROM assessments of 1 site and 2 had ROM assessments of 2 sites. Of these assessments, 6 revealed increased ROM during drug intervention while 1 revealed a decreased ROM. There was an overall improvement in the mental composite score of the SF36 while physical composite score was decreased and the vitality score was unchanged. Two patients were removed from the study because of syncopal episodes.

CONCLUSION

Several patients experienced improved function of at least 25% and reported subjective improvement. Pirfenidone may benefit patients with radiation-induced fibrosis and is worthy of a larger well controlled trial.

Simple determination of pirfenidone in rat plasma via high-performance liquid chromatography

A simple, rapid and reliable high-performance liquid chromatographic method was developed and validated for the determination of pirfenidone and its major metabolites in rat plasma. Plasma proteins were precipitated with perchloric acid (10%, v/v) and the supernatant after centrifugation was determined using high-performance liquid chromatography. The analysis was carried out on a Lichrospher C(18) column (250 x 4.6 mm i.d., 5 microm). The mobile phase consisted of acetonitrile-water containing 0.2% acetic acid (23:77, v/v) at a flow-rate of 1 mL/min. The eluant was detected at 310 nm. The calibration curves were linear over a concentration range from 0.15 to 76.67 microg/mL. The accuracy (relative error) of the assay ranged from -2.6 to 7.9% and the precision (coefficient of variation) was less than 4.5%. The established method has been successfully applied to a pharmacokinetic study of pirfenidone following a single oral dose to rats.

Pirfenidone prevents the development of a vulnerable substrate for atrial fibrillation in a canine model of heart failure

BACKGROUND

Atrial fibrosis is an important substrate in atrial fibrillation (AF), particularly in the setting of structural heart disease. In a canine model, congestive heart failure (CHF) produces significant atrial fibrosis and the substrate for sustained AF. This atrial remodeling is a potential therapeutic target. The objective of the present study is to evaluate the effects of the antifibrotic drug pirfenidone (PFD) on arrhythmogenic atrial remodeling in a canine CHF model.

METHODS AND RESULTS

We studied 15 canines, divided equally into 3 groups: control, CHF canines not treated with PFD, and CHF canines treated with PFD. CHF was induced by ventricular tachypacing (220 bpm for 3 weeks), and oral PFD was administered for the 3-week pacing period. We performed electrophysiology and AF vulnerability studies, atrial fibrosis measurements, and atrial cytokine expression studies. Only canines in the untreated CHF group developed sustained AF (>30 minutes, 4 of 5 canines; P<0.05). Treatment of CHF canines with PFD resulted in an attenuation of arrhythmogenic left atrial remodeling, with a significant reduction in left atrial conduction heterogeneity index (median [25% to 75% interquartile range] 4.96 [3.53 to 5.64] versus 2.52 [2.11 to 2.82], P<0.01; pacing cycle length 300 ms), left atrial fibrosis (16.0% [13.0% to 17.5%] versus 8.7% [5.7% to 10.6%], P<0.01), and AF duration (1800 [1020 to 1800] seconds versus 6 [5 to 22] seconds, P<0.01). Immunoblotting studies demonstrated the drug's effects on multiple cytokines, including a reduction in transforming growth factor-beta1 expression.

CONCLUSIONS

Treatment of CHF canines with PFD results in significantly reduced arrhythmogenic atrial remodeling and AF vulnerability. Pharmacological therapy targeted at the fibrotic substrate itself may play an important role in the management of AF.

Influence of pirfenidone on airway hyperresponsiveness and inflammation in a Brown-Norway rat model of asthma

Pirfenidone was administered to sensitized Brown Norway rats prior to a series of ovalbumin challenges. Airway hyperresponsiveness, inflammatory cell infiltration, mucin and collagen content, and the degree of epithelium and smooth muscle staining for TGF-beta were examined in control, sensitized, and sensitized/challenged rats fed a normal diet or pirfenidone diet. Pirfenidone had no effect on airway hyperresponsiveness, but reduced distal bronchiolar cell infiltration and proximal and distal mucin content. Statistical analysis showed that the control group and sensitized/challenged pirfenidone diet group TGF-beta staining intensity scores were not significantly different from isotype controls, but that the staining intensity scores for the sensitized/challenged normal diet group was significantly different from isotype controls. These results suggest that pirfenidone treatment is effective in reducing some of the components of acute inflammation induced by allergen challenge.

Pirfenidone modulates airway responsiveness, inflammation, and remodeling after repeated challenge

We investigated the therapeutic potential of a newly developed antifibrotic agent, pirfenidone, to regulate airway remodeling and the development of allergic airway inflammation and airway hyperresponsiveness after chronic allergen challenge. Administration of pirfenidone after sensitization but during the period of ovalbumin challenge significantly prevented the development of airway hyperresponsiveness and prevented eosinophil and lymphocyte accumulation in the airways. IL-4, IL-5, and IL-13 levels in bronchoalveolar lavage fluid and ovalbumin-specific serum IgE antibody levels were also significantly reduced. Treatment with pirfenidone significantly reduced transforming growth factor-beta1 and platelet-derived growth factor levels in bronchoalveolar lavage fluid. Pirfenidone reduced the expression of transforming growth factor-beta1, the development of goblet cell hyperplasia and subepithelial collagenization, and the increases in contractile elements in the lung. These data indicate that pirfenidone may play an important role in the treatment of asthma and has the potential reduce or prevent airway remodeling.

Pirfenidone: anti-fibrotic agent with a potential therapeutic role in the management of transplantation patients

Pirfenidone has a simple chemical structure, but may have profound implications for transplantation management. One of the leading causes of allograft failure is chronic allograft dysfunction, manifested by chronic inflammation and chronic fibrosis [Estenne, M., Hertz, M.I., 2002. Bronchiolitis obliterans after human lung transplantation. AJRCCM. 166, 440-444.]. This review summarizes the literature to date on Pirfenidone in the setting of transplantation, and those studies pertinent to the mechanisms of organ rejection and possible use of Pirfenidone in transplantation patients.

Pulmonary fibrosis in hermansky-pudlak syndrome. a case report and review

Hermansky-Pudlak syndrome (HPS) is a rare heterogeneously inherited autosomal recessive group of disorders presenting with oculocutaneous albinism, bleeding diathesis and pulmonary disease. HPS is thought to occur as a consequence of disturbed formation or trafficking of intracellular vesicles, most importantly, melanosomes, platelet dense granules and lysosomes. The latter finding, in particular, contributes much to the morbidity associated with the disease, as ceroid lipofuscin deposits in lysosomes affect many organ systems. This is especially problematic in the lungs where it is often associated with pulmonary fibrosis and premature death. Currently, there are 7 known HPS genes in humans. In the mouse, at least 16 known HPS genes produce HPS-mutant phenotypes. The HPS gene mutation is considered to be one of the most prevalent single-gene disorders in northwest Puerto Rico, home to the largest cohort of known patients. In HPS, interventions addressing the bleeding diathesis and pulmonary fibrosis are often disappointingly ineffectual. Pirfenidone, a novel compound with documented anti-inflammatory, antioxidant and antifibrotic effects, appears to hold promise in delaying or preventing fibrosis. To date, there has been one successful lung transplant performed on a patient with HPS. We present a patient with HPS and review the current literature on our understanding of this rare disorder.

A double-blind, randomized, controlled study of oral pirfenidone for treatment of secondary progressive multiple sclerosis

Currently, there are no approved treatments for secondary progressive multiple sclerosis (MS) that stabilize or reverse the neurological disabilities associated with this disease. Oral pirfenidone was found to stabilize and overcome the disabilities in two published independent open-label studies in secondary progressive MS. This led us to study pirfenidone in a phase II double-blind, randomized and controlled, clinical trial in patients with advanced secondary progressive MS for 12 months. Forty-three patients met the eligibility criteria approved by the IRB and accepted by the FDA. Of these patients, 18 were randomly assigned to placebo and 25 patients to oral pirfenidone groups. All eligible patients were included in the statistical analysis of the data according to intention-to-treat principles. Some patients on oral pirfenidone manifested mild drug-related adverse effects, but it was well tolerated overall. By one month, pirfenidone significantly (P < 0.05) improved the Scripps Neurological Rating Scale (SNRS) scores, and scores remained significantly improved for 3, 6 and 12 months when compared to the baseline SNRS scores. In contrast, the SNRS scores of patients on oral placebo were not significantly improved at 1, 3, 6 or 12 months of the study, when compared with baseline scores. Oral pirfenidone significantly (P <0.04) reduced the incidence of relapses (27.8% on placebo versus 8.0% on pirfenidone). Furthermore, oral pirfenidone treatment was associated with a marked improvement in bladder dysfunction (40.0% on pirfenidone versus 16.7% on placebo). Expanded Disability Status Scale scores and MRI lesion count were not significantly different in the placebo and pirfenidone groups. These findings indicate a significant effect of pirfenidone on clinical disability and bladder function for secondary progressive MS patients. A major multicentre, double-blind, randomized, controlled trial is justified.

Effect of Pirfenidone on Apoptosis-Regulatory Genes in Chronic Cyclosporine Nephrotoxicity

BACKGROUND

: Apoptosis was shown to play a role in the progression of fibrosis in a chronic cyclosporine A (CsA) nephrotoxicity animal model. In addition, the antifibrotic molecule pirfenidone (PFD) was shown to ameliorate fibrosis in this model. We evaluated the role of PFD on the expression of apoptosis-regulatory genes in the kidneys of CsA-treated rats.

METHODS

: Rats were administered CsA 7.5 mg/kg per day, CsA+PFD (250 mg/kg/day), vehicle (VH), or VH+PFD, and sacrificed at 28 days. Physiologic and histologic changes were studied, and apoptosis was detected by terminal deoxynucleotide transferase-mediated dUTP nick-end labeling stain. The mRNA expression of pro-apoptotic genes p53 and Fas-ligand was evaluated by quantitative polymerase chain reaction, and that of Bcl-xL, an anti-apoptotic gene, was evaluated by Northern blot analysis. In addition to mRNA expression, immunohistochemical studies of caspase 3 were performed.

RESULT

: PFD administration to CsA-treated rats significantly ameliorated nephrotoxicity. Apoptosis-positive cells were increased by CsA but significantly reduced by PFD treatment (68+/-19 vs. 3+/-1, P<0.01). In addition, PFD down-regulated the mRNA expression of CsA-induced p53 and Fas-ligand (P<0.01) and increased that of Bcl-xL, previously reduced by CsA (P<0.01). Finally, PFD significantly down-regulated caspase 3 expression, present mostly on renal tubular epithelial cells. None of these changes were observed in VH-treated rats.

CONCLUSION

: Whereas CsA favored the expression of pro-apoptotic genes, that effect was ameliorated by PFD. Because apoptosis can partly explain the loss of cells associated with fibrosis, the influence of PFD on apoptosis-regulatory genes in a manner that reduces apoptosis may explain some of its antifibrotic properties.

Survival of Human Neurofibroma in Immunodeficient Mice and Initial Results of Therapy With Pirfenidone

Neurofibromatosis type I is a common tumor predisposing disease in humans. Surgical therapy can be applied only in selected patients with resectable masses. Hence, development of new therapies for this disease is urgent. We used human neurofibroma implants in mice with severe combined immunodeficiency (SCID) as a model to test the toxicity and potential efficacy of pirfenidone, a new therapeutic agent. Two hundred twelve human neurofibromas were transplanted into various locations in 59 experimental animals, and 30 mice with implants received oral pirfenidone for up to six weeks. Survival of neurofibromas in animals treated with pirfenidone was lower than in the control group $(P=.02)$. Tumors did not change histologic appearance or vascularization in response to pirfenidone. Treatment with pirfenidone, a new antifibrotic agent, inhibits survival of some tumors without causing toxicity in animals.

Open-label study of pirfenidone in patients with progressive forms of multiple sclerosis

BACKGROUND

Pirfenidone is an oral medication with a number of actions affecting the immune system. It has been proposed as a possible treatment for multiple sclerosis (MS).

METHODS

An early-phase study of progressive forms of MS was conducted. Pirfenidone was slowly titrated to 2400 mg/day. Safety, clinical, quality-of-life, and magnetic resonance image (MRI) outcomes were measured.

RESULTS

Twenty people were enrolled (13 with secondary progressive and seven with primary progressive MS). The mean age was 47.7 years; the mean Expanded Disability Status Scale (EDSS) was 5.15; 75% were female. Eighteen patients achieved the full dose, although five additional patients eventually had to decrease the dose, primarily because of nausea. The Neurologic Rating Scale showed a slight worsening, from 69.8+/-8.4 at baseline to 71.8+/-8.9 at one year (P = 0.03). Other clinical outcomes remained stable, including the EDSS, ambulation index, and nine-hole peg test. The Short-Form Health Survey (SF-36) quality-of-life measure remained unchanged. Comparisons of MRI scans at baseline and one year found that 715 plaques were unchanged, six were better, and 10 were worse. Three patients had plaques that improved and two patients had plaques that were worse. There were eight gadolinium-enhancing lesions on the baseline scans and 14 on the one-year scans.

CONCLUSIONS

Pirfenidone was well tolerated in patients with MS. Patients with primary progressive or secondary progressive MS tolerated the medication and remained clinically stable during the one year of follow up. Placebo-controlled blinded studies are needed to determine clinical effectiveness.

Pirfenidone: A novel anti-fibrotic agent and progressive chronic allograft rejection

In our established model of heterotopic tracheal transplantation, at day 28 following transplantation, obliteration of the lumen is observed, which is histologically similar to that seen in Obliterative Bronchiolitis (OB). Pirfenidone (Pir) is a novel anti-fibrotic agent that causes no immunosuppression, but does downregulate the production of TGF-beta and collagen in vitro. We hypothesized that when used in this in vivo model, that Pir may alter the observed luminal fibrosis and obliteration.

METHODS

The treatment groups were: CSA, Pir and CSA, Pir only (n=6 each). Luminal supernatants and tissue were obtained from these groups at day 28. H&E staining was completed, as well as MTS proliferation assays, and TGF-beta ELISA on the fluids.

RESULTS

The CSA-Pir combined treatment group was the least fibrogenic in vitro (p<0.001). The TGF-beta levels were elevated in all groups (range 203-372 pg/ml). The H&E staining revealed that the luminal obliteration was less organized in the combined CSA-Pir group.

CONCLUSIONS

Our study shows that the combination of CSA-Pir results in a less fibrogenic luminal fluid and a less dense fibrous luminal plug. Pir should be further studied in obliterative airways disease (OAD).

Pirfenidone attenuates ischaemia-reperfusion injury in the rat small intestine

1. Pirfenidone, an antifibrotic compound with anti-inflammatory effects, has been investigated in a rat model of acute experimental ischaemia-reperfusion injury of the small intestine. 2. Occlusion of the superior mesenteric artery in young adult female rats for 30 min followed by reperfusion for 120 min induced significant local and systemic effects, including tissue haemorrhage with oedema, elevated serum concentrations of tumour necrosis factor (TNF)-alpha, neutropenia, hypotension and bradycardia. 3. Administration of pirfenidone (200 mg/kg, p.o., i.v. or i.p.) 30 min before occlusion completely inhibited the increase in serum TNF-alpha concentrations. Pirfenidone inhibited, but did not completely prevent, tissue damage in the small intestine, as well as hypotension and oedema, but neutropenia and bradycardia were not significantly changed by treatment. 4. Thus, pirfenidone effectively moderates both local and some systemic effects of ischaemia-reperfusion injury in the rat small intestine model.

Pirfenidone blocks the in vitro and in vivo effects of staphylococcal enterotoxin B

Pirfenidone [5-methyl-1-phenyl-2-(1H)-pyridone] down-regulates expression of cytokines and other mediators involved in the onset and development of pulmonary fibrosis. Pirfenidone also inhibits production of tumor necrosis factor alpha (TNF-alpha) from macrophages incubated with endotoxin and protects mice against endotoxin shock. Pirfenidone's ability to reduce cytokine expression in these disorders led us to investigate the drug's effect on another cytokine anomaly, superantigen-induced shock. BALB/c mice were exposed to staphylococcal enterotoxin B (SEB) either systemically or by aerosol and subsequently potentiated with a sublethal dose of lipopolysaccharide. In these experiments, pirfenidone given 2 to 4.25 h after SEB resulted in 80 to 100% survival versus only 0 to 10% survival among untreated control animals. Relative to serum cytokine levels from controls given toxin but no drug, there was a 35 to 80% decrease in TNF-alpha, interleukin 1, and other proinflammatory cytokines. In vitro experiments with human peripheral blood lymphocytes revealed that pirfenidone reduced SEB-induced cytokine levels 50 to 80% and inhibited 95% of SEB-induced T-cell proliferation. Overall, these studies demonstrated the potential utility of pirfenidone as a therapeutic against septic shock and the biological effects of SEB.

Pirfenidone treatment decreases transforming growth factor-beta1 and matrix proteins and ameliorates fibrosis in chronic cyclosporine nephrotoxicity

Chronic cyclosporine (CsA) nephrotoxicity is characterized by tubulointerstitial fibrosis. Pirfenidone (PFD) is a novel antifibrotic compound that was shown to prevent and even reverse fibrosis. The mechanism of action of PFD is unclear but involves inhibition of transforming growth factor-beta (TGF-beta). Salt-depleted rats were administered CsA, CsA + PFD, vehicle (VH) or VH + PFD and sacrificed at 28days. Physiologic and histologic changes were studied in addition to TGF-beta1, plasminogen activator inhibitor-1 (PAI-1) and biglycan mRNA expressions by Northern blot. TGF-beta1 immunohistochemistry was also performed. Treatment with PFD ameliorated CsA-induced fibrosis by about 50% (p < 0.05). CsA-induced decrease in creatinine clearance improved with PFD but the difference was not significant. TGF-beta1, PAI-1 and biglycan mRNA expressions increased with CsA (p < 0.05 vs. VH) but strikingly improved with PFD treatment (p < 0.05 vs. CsA), which brought the levels down to VH levels. PFD treatment also decreased TGF-beta1 protein expression by 80%. These results demonstrate that PFD can attenuate renal fibrosis in this model. PFD was associated with a decrease in TGF-beta1 expression, which, in turn, was associated with a decrease in matrix deposition. These experiments suggest that PFD can be clinically useful for preventing chronic CsA nephrotoxicity and may prove to be helpful in other progressive renal diseases.

Pirfenidone in the treatment of primary sclerosing cholangitis

Our aim was to evaluate the safety and assess the efficacy of pirfenidone, an antifibrotic drug, in patients with primary sclerosing cholangitis (PSC). Twenty-four patients with PSC were enrolled in this pilot study. Oral pirfenidone, 2400 mg daily, was given for one year. Liver biochemistries were determined at three-month intervals. The Mayo risk score was calculated, and liver biopsy and endoscopic cholangiography were performed at entry and at one year of treatment. No significant changes in liver biochemistries were noted at the end of the treatment period or at any of the three-month intervals. The Mayo risk score did not change significantly, and no significant changes were noted in the degree of inflammation, fibrosis, histologic stage of disease, or cholangiographic findings at the end of the treatment period. Adverse events occurred in 20/24 (83%) patients, but disappeared shortly after pirfenidone was discontinued. Pirfenidone did not benefit patients with PSC, and it was frequently associated with adverse events. The results of this pilot study discourage further trials of pirfenidone in patients with PSC.

A phase II trial of pirfenidone (5-methyl-1-phenyl-2-[1H]-pyridone), a novel anti-fibrosing agent, in myelofibrosis with myeloid metaplasia

The anti-fibrotic and cytokine modulatory properties of pirfenidone suggest its usefulness in the treatment of myelofibrosis with myeloid metaplasia (MMM). In a prospective study, 28 patients with MMM were treated with oral pirfenidone. Twelve patients completed 1 year of therapy; 13 were withdrawn because of disease progression and three because of drug intolerance. Only one patient experienced a clinically relevant benefit with respect to anaemia and splenomegaly. The overall lack of clinical benefit correlated with no significant improvement in the bone marrow morphological features of the disease. We conclude that pirfenidone has no significant clinical or biological activity in MMM.

Anti-inflammatory effect of pirfenidone in the bleomycin-hamster model of lung inflammation

We have previously reported the antifibrotic effects of pirfenidone (PD) in the bleomycin (BL)-hamster model of lung fibrosis. Since the development of fibrosis is generally preceded by acute lung inflammation, the present study was conducted to find out if dietary intake of PD (0.5%) has any effects on BL-induced lung inflammation. In this regard, we evaluated the effects of PD on BL-induced increased pulmonary vascular permeability, increased influx of inflammatory cells and increased levels of TGF-beta in the bronchoalveolar lavage fluid (BALF). Hamsters were intratracheally (IT) instilled with saline (SA) or BL (5.5 units/kg/5 ml). The animals were fed the control diet (CD) or the same diet containing 0.5% PD 2 days prior to IT instillation and throughout the study. The bronchoalveolar lavage was carried out at different times after IT instillation. Lavage fluid was used for total and differential cell counts and BALF-supernatant for measurement of total protein and TGF-beta. IT instillation of BL caused significant increases in total cells, neutrophils, macrophages and lymphocytes and in the levels of total protein and TGF-beta in BALF from hamsters in the BL + CD groups as compared to the corresponding SA + CD control groups. In contrast, treatment with pirfenidone in general, suppressed the BL-induced increases in the levels of proteins and TGF-beta and in the influx of neutrophils, macrophages and lymphocytes in BALF at the early time points in BL + PD groups. Based on the data reported in this study, we conclude that the anti-inflammatory effects of pirfenidone as evident by suppressions of BL-induced increased pulmonary vascular permeability and increased influx of inflammatory cells in the lung contribute additionally to its inherent anti-fibrotic effect.

Pirfenidone inhibits NADPH-dependent microsomal lipid peroxidation and scavenges hydroxyl radicals

Pirfenidone (Pf), a new broad-spectrum anti-fibrotic agent, is known to offer protection against lung fibrosis in vivo in laboratory animals, and against mitogenesis and collagen formation by human lung fibroblasts in vitro. Because reactive oxygen species are thought to be involved in these events, we investigated the mechanism(s) by which Pf ameliorates oxidative stress and its effects on NADPH-dependent lipid peroxidation. Pf has been shown to cause inhibit NADPH-dependent lipid peroxidation in sheep liver microsomes in a dose-dependent manner. The concentration of Pf required to cause 50% inhibition of lipid peroxidation was approximately 6 mM. Pf was found to be ineffective as a superoxide radical scavenger. Pf was also ineffective in decomposing H2O2 and chelating iron. In deoxyribose degradation assays, Pf was a potent scavenger of hydroxyl radicals with a rate constant of 5.4 x 10(9) M(-1) sec(-1). EPR spectroscopy in combination with spin trapping techniques, using a Fenton type reaction and DMPO as a spin-trapping agent, Pf scavenged hydroxyl radicals in a dose-dependent manner. The concentration of Pf required to inhibit 50% signal height was approximately 2.5 mM. Because iron was used in the Fenton reaction, the ability of Pf in chelating iron was verified in a fluorescent competitive assay using calcein as the fluorescent probe. Pf up to 10 mM concentration was ineffective in chelating either Fe2+ or Fe3+ in this system. We propose that Pf exerts its beneficial effects, at least in part, through its ability to scavenge toxic hydroxyl radicals.