Mutant soluble ectodomain of fibroblast growth factor receptor-2 IIIc attenuates bleomycin-induced pulmonary fibrosis in mice

Antifibrotic Drugs against Idiopathic Pulmonary Fibrosis and Pulmonary Fibrosis Induced by COVID-19: Therapeutic Approaches and Potential Diagnostic Biomarkers

The COVID-19 pandemic has had a significant impact on the health and economy of the global population. Even after recovery from the disease, post-COVID-19 symptoms, such as pulmonary fibrosis, continue to be a concern. This narrative review aims to address pulmonary fibrosis (PF) from various perspectives, including the fibrotic mechanisms involved in idiopathic and COVID-19-induced pulmonary fibrosis. On the other hand, we also discuss the current therapeutic drugs in use, as well as those undergoing clinical or preclinical evaluation. Additionally, this article will address various biomarkers with usefulness for PF prediction, diagnosis, treatment, prognosis, and severity assessment in order to provide better treatment strategies for patients with this disease.

Inflammatory Markers Involved in the Pathogenesis of Dupuytren's Contracture

Dupuytren's disease is a common fibroproliferative disease that can result in debilitating hand deformities. Partial correction and return of deformity are common with surgical or clinical treatments at present. While current treatments are limited to local procedures for relatively late effects of the disease, the pathophysiology of this connective tissue disorder is associated with both local and systemic processes (e.g., fibrosis, inflammation). Hence, a better understanding of the systemic circulation of Dupuytren related cytokines and growth factors may provide important insights into disease progression. In addition, systemic biomarker analysis could yield new concepts for treatments of Dupuytren that attenuate circulatory factors (e.g., anti-inflammatory agents, neutralizing antibodies). Progress in the development of any disease modifying biologic treatment for Dupuytren has been hampered by the lack of clinically useful biomarkers. The characterization of nonsurgical Dupuytren biomarkers will permit disease staging from diagnostic and prognostic perspectives, as well as allows evaluation of biologic responses to treatment. Identification of such markers may transcend their use in Dupuytren treatment, because fibrotic biological processes fundamental to Dupuytren are relevant to fibrosis in many other connective tissues and organs with collagen-based tissue compartments. There is a wide range of potential Dupuytren biomarker categories that could be informative, including disease determinants linked to genetics, collagen metabolism, as well as immunity and inflammation (e.g., cytokines, chemokines). This narrative review provides a broad overview of previous studies and emphasizes the importance of inflammatory mediators as candidate circulating biomarkers for monitoring Dupuytren's disease.

The polymorphisms of FGFR2 and MGAT5 affect the susceptibility to COPD in the Chinese people

Background

Chronic obstructive pulmonary disease (COPD) is characterized by incomplete reversible airflow limitation and chronic inflammatory response lesions. This study mainly explored whether FGFR2 and MGAT5 polymorphisms affected the risk of COPD in the Chinese people.

Methods

Five variants in FGFR2 and MGAT5 were chosen and genotyped using Agena MassARRAY platform from 315 COPD patients and 314 healthy controls. The correlation of FGFR2 and MGAT5 with COPD susceptibility was evaluated with odds ratio (OR) and 95% confidence interval (CI) via logistic regression.

Results

We found rs2420915 enhanced the risk of COPD, while rs6430491, rs2593704 reduced the susceptibility of COPD (p < 0.05). Rs2420915 could promote the incidence of COPD in the elderly and nonsmokers. Rs1907240 and rs2257129 also increased the susceptibility to COPD in nonsmokers (p < 0.05). MGAT5-rs2593704 played a protective role in COPD development in different subgroups (age ≤ 70, male, smokers, and individuals with BMI ≤ 24 kg/m²). Meanwhile, rs6430491 was linked with a lower risk of COPD in nonsmoking and BMI ≤ 24 kg/m² subgroups.

Conclusions

We concluded that FGFR2 and MGAT5 genetic polymorphisms are correlated with the risk of COPD in the Chinese people. These data underscored the important role of FGFR2 and MGAT5 gene in the occurrence of COPD and provided new biomarkers for COPD treatment.

Trial registration: NA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01498-3.

Nintedanib promotes antitumour immunity and shows antitumour activity in combination with PD-1 blockade in mice: potential role of cancer-associated fibroblasts

BACKGROUND

Cancer-associated fibroblasts (CAFs) in the tumour microenvironment (TME) suppress antitumour immunity, and the tyrosine kinase inhibitor nintedanib has antifibrotic effects.

METHODS

We performed a preclinical study to evaluate whether nintedanib might enhance antitumour immunity by targeting CAFs and thereby improve the response to immune checkpoint blockade (ICB).

RESULTS

Whereas nintedanib did not suppress the growth of B16-F10 melanoma cells in vitro, it prolonged survival in a syngeneic mouse model of tumour formation by these cells, suggestive of an effect on the TME without direct cytotoxicity. Gene expression profiling indeed showed that nintedanib influenced antitumour immunity and fibrosis. Tumoural infiltration of CD8⁺ T cells and granzyme B production were increased by nintedanib, and its antitumour activity was attenuated by antibody-mediated depletion of these cells, indicating that nintedanib suppressed tumour growth in a CD8⁺ T cell-dependent manner. Moreover, nintedanib inhibited the proliferation and activation of fibroblasts. Finally, the combination of nintedanib with ICB showed enhanced antitumour efficacy in B16-F10 tumour-bearing mice.

CONCLUSIONS

Our results suggest that nintedanib targeted CAFs and thereby attenuated the immunosuppressive nature of the TME and promoted the intratumoural accumulation and activation of CD8⁺ T cells, with these effects contributing to enhanced antitumour activity in combination with ICB.

Blockade of Pan-Fibroblast Growth Factor Receptors Mediates Bidirectional Effects in Lung Fibrosis

FGFs (fibroblast growth factors) are major factors associated with the pathogenesis of pulmonary fibrosis. On the one hand, nintedanib, a tyrosine kinase inhibitor targeting several growth factor receptors, including the FGF receptor (FGFR), has been approved for the treatment of idiopathic pulmonary fibrosis. On the other hand, recent reports suggest that FGFs are required for epithelial recovery. In this study, we focused on FGF signaling to both fibroblasts and alveolar epithelial cells (AECs), and we examined the effect of a pan-FGFR blocker on experimental pulmonary fibrosis in mice. The effects of BGJ398, a pan-FGFR inhibitor, on the migration and proliferation of fibroblasts and AECs were assessed using Transwell migration or [³H]thymidine incorporation assays. The expression of FGFR was analyzed using IB or flow cytometry. We also investigated the effect of BGJ398 on pulmonary fibrosis induced by bleomycin in mice. Both lung fibroblasts and AECs expressed FGFRs. BGJ398 significantly inhibited the proliferation and migration of lung fibroblasts stimulated with FGF2. BGJ398 also reduced the proliferation of AECs in response to FGF2. Although the administration of BGJ398 ameliorated pulmonary fibrosis in bleomycin-treated mice, it increased mortality resulting from alveolar injury and inhibition of AEC regeneration. These data suggest that the total inhibition of FGFR signaling can suppress lung fibrosis by inhibiting fibroblast activities, although alveolar injury is simultaneously caused.

Inhibitory effects of msFGFR2c on the epithelial-to-mesenchymal transition of AE2 cells in pulmonary fibrosis

In interstitial fibrosis, alveolar epithelial type II (AE2) cells fail to repair damaged epithelium. However, whether this dysfunction is related to fibroblast growth factor (FGF) signal pathway and how it affects the fibrotic process remains unclear. In our study, the medium of the human foetal lung fibroblast cell line MRC-5 (Med) can induce epithelial-to-mesenchymal transition (EMT) in AE2 cells, we also found that TGF-β in Med can induce FGF-2 and CTGF expression in AE2 cells. TGF-β or CTGF exposure trigger a FGFR2 subtype b to c transition which can be supressed by siRNA-CTGF. All together, since FGFR2IIIc have the highest affinity with FGF-2 in all of the FGFRs, we indicate the activation of FGF2 signal pathway was induced by TGF-β, which is the key component of Med Here, we also find the inhibitory effect of msFGFR2c (S252W mutant of soluble FGFR2IIIc extracellular domain) on EMT of mouse primary AE2 cells in pulmonary fibrotic process. In a bleomycin-induced mouse pulmonary fibrosis model, msFGFR2c alleviate pulmonary fibrosis and suppress the decrease in pro-SPC levels. Thus, msFGFR2c can inhibit EMT-induced fibrosis of AE2 cells via FGF-2 signal and AE2 cells is suggested to play an important role in the lung fibrotic process.

Nintedanib: New indication for systemic sclerosis-associated interstitial lung disease

Nintedanib (Ofev™), an oral triple kinase inhibitor targeting pro-fibrotic pathways, has been used for treatment of idiopathic pulmonary fibrosis (IPF). Based on positive results from phase III, placebo-controlled, randomized comparative clinical trial conducted in patients with systemic sclerosis-associated interstitial lung disease (SSc-ILD), nintedanib received marketing approval in the United States and Japan for the treatment of SSc-ILD. Nintedanib significantly reduced the annual rate of decline in forced vital capacity over 52 weeks compared with placebo. The safety profiles observed in this trial were consistent with those reported in IPF patients, and the most common adverse events were gastrointestinal disorders, including diarrhea, nausea, and vomiting, which sometimes lead to discontinuation or permanent dose reduction of nintedanib. In contrast, serious adverse events were infrequent and were related mostly to worsening of cardiopulmonary involvement of SSc. This review summarizes the milestones in development of nintedanib leading to the approval for the treatment of SSc-ILD, and covers mechanisms of action, efficacy results and safety profiles, and future perspectives of nintedanib.

Novel Pyrimidines as Multitarget Protein Tyrosine Kinase Inhibitors for the Treatment of Idiopathic Pulmonary Fibrosis (IPF)

A new class of pyrimidine derivatives were identified as potent protein tyrosine kinase (PTK) inhibitors for the treatment of idiopathic pulmonary fibrosis (IPF). Most of these small-molecule inhibitors displayed strong enzymatic activity against BTK and JAK3 kinases at concentrations lower than 10 nM. The representative compound N-(3-((5-chloro-2-(4-((1-morpholino)acetylamino)phenylamino)-4-pyrimidinyl)amino)phenyl)acrylamide (6 a) also exhibited high inhibitory potency toward both BTK and JAK kinase families, as well as ErbB4, at a concentration of 10 nM, achieving rates of inhibition higher than 57 %. Additionally, in vivo biological evaluations showed that 6 a can remarkably decrease the severity of IPF disease. All these investigations suggested that the multi-PTK inhibitor 6 a may serve as a promising agent for the treatment of IPF.

A new FGFR inhibitor disrupts the TGF-β1-induced fibrotic process

Pulmonary fibrosis (PF) is chronic and irreversible damage to the lung characterized by fibroblast activation and matrix deposition. Although recently approved novel anti‐fibrotic agents can improve the lung function and survival of patients with PF, the overall outcomes remain poor. In this study, a novel imidazopurine compound, 3‐(2‐chloro‐6‐fluorobenzyl)‐1,6,7‐trimethyl‐1H‐imidazo[2,1‐f]purine‐2,4(3H,8H)‐dione (IM‐1918), markedly inhibited transforming growth factor (TGF)‐β‐stimulated reporter activity and reduced the expression of representative fibrotic markers, such as connective tissue growth factor, fibronectin, collagen and α‐smooth muscle actin, on human lung fibroblasts. However, IM‐1918 neither decreased Smad‐2 and Smad‐3 nor affected p38MAPK and JNK. Instead, IM‐1918 reduced Akt and extracellular signal‐regulated kinase 1/2 phosphorylation increased by TGF‐β. Additionally, IM‐1918 inhibited the phosphorylation of fibroblast growth factor receptors 1 and 3. In a bleomycin‐induced murine lung fibrosis model, IM‐1918 profoundly reduced fibrotic areas and decreased collagen and α‐smooth muscle actin accumulation. These results suggest that IM‐1918 can be applied to treat lung fibrosis.

The Importance of Tyrosine Phosphorylation Control of Cellular Signaling Pathways in Respiratory Disease: pY and pY Not

Reversible phosphorylation of proteins on tyrosine residues is an essential signaling mechanism by which diverse cellular processes are closely regulated. The tight temporal and spatial control of the tyrosine phosphorylation status of proteins by protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs) is critical to cellular homeostasis as well as to adaptations to the external environment. Via regulation of cellular signaling cascades involving other protein kinases and phosphatases, receptors, adaptor proteins, and transcription factors, PTKs and PTPs closely control diverse cellular processes such as proliferation, differentiation, migration, inflammation, and maintenance of cellular barrier function. Given these key regulatory roles, it is not surprising that dysfunction of PTKs and PTPs is important in the pathogenesis of human disease, including many pulmonary diseases. The roles of various PTKs and PTPs in acute lung injury and repair, pulmonary fibrosis, pulmonary vascular disease, and inflammatory airway disease are discussed in this review. It is important to note that although there is overlap among many of these proteins in various disease states, the mechanisms by which they influence the pathogenesis of these conditions differ, suggesting wide-ranging roles for these enzymes and their potential as therapeutic targets.

Subgroup Analysis for Chinese Patients Included in the INPULSIS® Trials on Nintedanib in Idiopathic Pulmonary Fibrosis

PURPOSE

To investigate the efficacy and safety of nintedanib versus placebo in Chinese patients with idiopathic pulmonary fibrosis (IPF).

METHODS

The INPULSIS^® trials consisted of two replicate, randomized, placebo-controlled, double-blind trials comparing nintedanib 150 mg bid with placebo over a 52-week treatment period. The primary endpoint was annual rate of decline in forced vital capacity (FVC); key secondary endpoints were change from baseline in Saint George's Respiratory Questionnaire's total score and time to first investigator-reported acute exacerbation. Data from both trials were pooled for the Chinese subgroup analyses.

RESULTS

A total of 101 Chinese patients (nintedanib/placebo: 61/40) were treated. The demographic characteristics were generally balanced between treatment arms. Over 52 weeks, the rate of decline in FVC was lower in nintedanib-treated patients compared with placebo-treated patients in the Chinese subgroup [- 126.43 vs. - 229.82 mL/year; ∆ = 103.39 mL/year (95% confidence interval, CI: - 19.40 to 226.18)]. The proportion of patients with adverse events (AEs) over 52 weeks was similar between treatment arms. The most commonly reported AEs with nintedanib treatment were gastrointestinal symptoms (diarrhoea, nausea, and vomiting).

CONCLUSIONS

Nintedanib is clinically efficacious in Chinese patients with IPF with approximately 50% reductions in the rate of decline in FVC, demonstrating slowed disease progression. Similar to the overall INPULSIS^® population, nintedanib has a favourable benefit/risk profile in Chinese patients with IPF. CLINICALTRIALS.

GOV IDENTIFIERS

NCT01335464, NCT01335477.

FUNDING

Boehringer Ingelheim. Plain language summary available for this article.

Fibroblast growth factor 2 decreases bleomycin-induced pulmonary fibrosis and inhibits fibroblast collagen production and myofibroblast differentiation

Fibroblast growth factor (FGF) signaling has been implicated in the pathogenesis of pulmonary fibrosis. Mice lacking FGF2 have increased mortality and impaired epithelial recovery after bleomycin exposure, supporting a protective or reparative function following lung injury. To determine whether FGF2 overexpression reduces bleomycin-induced injury, we developed an inducible genetic system to express FGF2 in type II pneumocytes. Double-transgenic (DTG) mice with doxycycline-inducible overexpression of human FGF2 (SPC-rtTA;TRE-hFGF2) or single-transgenic controls were administered intratracheal bleomycin and fed doxycycline chow, starting at either day 0 or day 7. In addition, wild-type mice received intratracheal or intravenous recombinant FGF2, starting at the time of bleomycin treatment. Compared to controls, doxycycline-induced DTG mice had decreased pulmonary fibrosis 21 days after bleomycin, as assessed by gene expression and histology. This beneficial effect was seen when FGF2 overexpression was induced at day 0 or day 7 after bleomycin. FGF2 overexpression did not alter epithelial gene expression, bronchoalveolar lavage cellularity or total protein. In vitro studies using primary mouse and human lung fibroblasts showed that FGF2 strongly inhibited baseline and TGFβ1-induced expression of alpha smooth muscle actin (αSMA), collagen, and connective tissue growth factor. While FGF2 did not suppress phosphorylation of Smad2 or Smad-dependent gene expression, FGF2 inhibited TGFβ1-induced stress fiber formation and serum response factor-dependent gene expression. FGF2 inhibition of stress fiber formation and αSMA requires FGF receptor 1 (FGFR1) and downstream MEK/ERK, but not AKT signaling. In summary, overexpression of FGF2 protects against bleomycin-induced pulmonary fibrosis in vivo and reverses TGFβ1-induced collagen and αSMA expression and stress fiber formation in lung fibroblasts in vitro, without affecting either inflammation or epithelial gene expression. Our results suggest that in the lung, FGF2 is antifibrotic in part through decreased collagen expression and fibroblast to myofibroblast differentiation. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Pulmonary fibrosis requires cell-autonomous mesenchymal fibroblast growth factor (FGF) signaling

Idiopathic pulmonary fibrosis (IPF) is characterized by progressive pulmonary scarring, decline in lung function, and often results in death within 3-5 five years after diagnosis. Fibroblast growth factor (FGF) signaling has been implicated in the pathogenesis of IPF; however, the mechanism through which FGF signaling contributes to pulmonary fibrosis remains unclear. We hypothesized that FGF receptor (FGFR) signaling in fibroblasts is required for the fibrotic response to bleomycin. To test this, mice with mesenchyme-specific tamoxifen-inducible inactivation of FGF receptors 1, 2, and 3 (Col1α2-CreER; TCKO mice) were lineage labeled and administered intratracheal bleomycin. Lungs were collected for histologic analysis, whole lung RNA and protein, and dissociated for flow cytometry and FACS. Bleomycin-treated Col1α2-CreER; TCKO mice have decreased pulmonary fibrosis, collagen production, and fewer α-smooth muscle actin-positive (αSMA+) myofibroblasts compared with controls. Freshly isolated Col1α2-CreER; TCKO mesenchymal cells from bleomycin-treated mice have decreased collagen expression compared with wild type mesenchymal cells. Furthermore, lineage labeled FGFR-deficient fibroblasts have decreased enrichment in fibrotic areas and decreased proliferation. These data identify a cell autonomous requirement for mesenchymal FGFR signaling in the development of pulmonary fibrosis, and for the enrichment of the Col1α2-CreER-positive (Col1α2+) mesenchymal lineage in fibrotic tissue following bleomycin exposure. We conclude that mesenchymal FGF signaling is required for the development of pulmonary fibrosis, and that therapeutic strategies aimed directly at mesenchymal FGF signaling could be beneficial in the treatment of IPF.

Therapeutic and pathological roles of fibroblast growth factors in pulmonary diseases

Fibroblast growth factors (FGFs) constitute a large family of polypeptides that are involved in many biological processes, ranging from prenatal cell-fate specification and organogenesis to hormonal and metabolic regulation in postnatal life. During embryonic development, these growth factors are important mediators of the crosstalk among ectoderm-, mesoderm-, and endoderm-derived cells, and they instruct the spatial and temporal growth of organs and tissues such as the brain, bone, lung, gut, and others. The involvement of FGFs in postnatal lung homeostasis is a growing field, and there is emerging literature about their roles in lung pathophysiology. In this review, the involvement of FGF signaling in a wide array of lung diseases will be summarized. Developmental Dynamics 246:235-244, 2017. © 2016 Wiley Periodicals, Inc.

Tyrosine kinase inhibitor BIBF1000 does not hamper right ventricular pressure adaptation in rats

BIBF1000 is a small molecule tyrosine kinase inhibitor targeting vascular endothelial growth factor receptor (VEGFR), fibroblast growth factor receptor (FGFR), and platelet-derived growth factor receptor (PDGFR) and is a powerful inhibitor of fibrogenesis. BIBF1000 is very similar to BIBF1120 (nintedanib), a drug recently approved for the treatment of idiopathic pulmonary fibrosis (IPF). A safety concern pertaining to VEGFR, FGFR, and PDGFR inhibition is the possible interference with right ventricular (RV) responses to an increased afterload, which could adversely affect clinical outcome in patients with IPF who developed pulmonary hypertension. We tested the effect of BIBF1000 on the adaptation of the RV in rats subjected to mechanical pressure overload. BIBF1000 was administered for 35 days in pulmonary artery-banded (PAB) rats. RV adaptation was assessed by echocardiography, pressure volume loop analysis, histology, and determination of atrial natriuretic peptide (ANP) expression. BIBF1000 treatment resulted in growth attenuation but had no effects on RV function after PAB, given absence of changes in cardiac index, end-systolic elastance, connective tissue disposition, and capillary density. We conclude that, in this experimental model of increased afterload, combined VEGFR, FGFR, and PDGFR inhibition does not hamper RV adaptation to pressure overload.

Idiopathic pulmonary fibrosis: current treatment options and critical appraisal of nintedanib

Idiopathic pulmonary fibrosis (IPF) is the most common type of idiopathic interstitial pneumonia and is characterized by a poor prognosis, with an estimated 5-year survival of approximately 20%. Progressive and irreversible lung functional impairment leads to chronic respiratory insufficiency with a severely impaired quality of life. In the last 2 decades, novel treatments for IPF have been developed as a consequence of an increasing understanding of disease pathogenesis and pathobiology. In IPF, injured dysfunctional alveolar epithelial cells promote fibroblast recruitment and proliferation, resulting in scarring of the lung tissue. Recently, pirfenidone and nintedanib have been approved for the treatment of IPF, having shown efficacy to slow functional decline and disease progression. This article focuses on the pharmacologic characteristics and clinical evidence supporting the use of nintedanib, a potent small-molecule tyrosine kinase inhibitor, as therapy for IPF. After introducing the mechanism of action and pharmacokinetics, an overview of the safety and efficacy results from the most recent clinical trials of nintedanib in IPF is presented.

Fibroblast growth factor 2 is required for epithelial recovery, but not for pulmonary fibrosis, in response to bleomycin

The pathogenesis of pulmonary fibrosis involves lung epithelial injury and aberrant proliferation of fibroblasts, and results in progressive pulmonary scarring and declining lung function. In vitro, fibroblast growth factor (FGF) 2 promotes myofibroblast differentiation and proliferation in cooperation with the profibrotic growth factor, transforming growth factor-β1, but the in vivo requirement for FGF2 in the development of pulmonary fibrosis is not known. The bleomycin model of lung injury and pulmonary fibrosis was applied to Fgf2 knockout (Fgf2(-/-)) and littermate control mice. Weight loss, mortality, pulmonary fibrosis, and histology were analyzed after a single intranasal dose of bleomycin. Inflammation was evaluated in bronchoalveolar lavage (BAL) fluid, and epithelial barrier integrity was assessed by measuring BAL protein and Evans Blue dye permeability. Fgf2 is expressed in mouse and human lung epithelial and inflammatory cells, and, in response to bleomycin, Fgf2(-/-) mice have significantly increased mortality and weight loss. Analysis of BAL fluid and histology show that pulmonary fibrosis is unaltered, but Fgf2(-/-) mice fail to efficiently resolve inflammation, have increased BAL cellularity, and, importantly, deficient recovery of epithelial integrity. Fgf2(-/-) mice similarly have deficient recovery of club cell secretory protein(+) bronchial epithelium in response to naphthalene. We conclude that FGF2 is not required for bleomycin-induced pulmonary fibrosis, but rather is essential for epithelial repair and maintaining epithelial integrity after bleomycin-induced lung injury in mice. These data identify that FGF2 acts as a protective growth factor after lung epithelial injury, and call into question the role of FGF2 as a profibrotic growth factor in vivo.

Mode of action of nintedanib in the treatment of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive and ultimately fatal disease characterised by fibrosis of the lung parenchyma and loss of lung function. Although the pathogenic pathways involved in IPF have not been fully elucidated, IPF is believed to be caused by repetitive alveolar epithelial cell injury and dysregulated repair, in which there is uncontrolled proliferation of lung fibroblasts and differentiation of fibroblasts into myofibroblasts, which excessively deposit extracellular matrix (ECM) proteins in the interstitial space. A number of profibrotic mediators including platelet-derived growth factor (PDGF), fibroblast growth factor (FGF) and transforming growth factor-β are believed to play important roles in the pathogenesis of IPF. Nintedanib is a potent small molecule inhibitor of the receptor tyrosine kinases PDGF receptor, FGF receptor and vascular endothelial growth factor receptor. Data from in vitro studies have shown that nintedanib interferes with processes active in fibrosis such as fibroblast proliferation, migration and differentiation, and the secretion of ECM. In addition, nintedanib has shown consistent anti-fibrotic and anti-inflammatory activity in animal models of lung fibrosis. These data provide a strong rationale for the clinical efficacy of nintedanib in patients with IPF, which has recently been demonstrated in phase III clinical trials.

Nintedanib interferes with processes active in fibrosis, e.g. fibroblast proliferation, migration anddifferentiationhttp://ow.ly/Iae9z

The role of tyrosine kinases in the pathogenesis of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease with a median survival time from diagnosis of 2-3 years. Although the pathogenic pathways have not been fully elucidated, IPF is believed to be caused by persistent epithelial injury in genetically susceptible individuals. Tyrosine kinases are involved in a range of signalling pathways that are essential for cellular homeostasis. However, there is substantial evidence from in vitro studies and animal models that receptor tyrosine kinases, such as the platelet-derived growth factor receptor, vascular endothelial growth factor receptor and fibroblast growth factor receptor, and non-receptor tyrosine kinases, such as the Src family, play critical roles in the pathogenesis of pulmonary fibrosis. For example, the expression and release of tyrosine kinases are altered in patients with IPF, while specific tyrosine kinases stimulate the proliferation of lung fibroblasts in vitro. Agents that inhibit tyrosine kinases have shown anti-fibrotic and anti-inflammatory effects in animal models of pulmonary fibrosis. Recently, the tyrosine kinase inhibitor nintedanib has shown positive results in two phase III trials in patients with IPF. Here, we summarise the evidence for involvement of specific tyrosine kinases in the pathogenesis of IPF and the development of tyrosine kinase inhibitors as treatments for IPF.

Nintedanib: from discovery to the clinic

Nintedanib (BIBF1120) is a potent, oral, small-molecule tyrosine kinase inhibitor, also known as a triple angiokinase inhibitor, inhibiting three major signaling pathways involved in angiogenesis. Nintedanib targets proangiogenic and pro-fibrotic pathways mediated by the VEGFR family, the fibroblast growth factor receptor (FGFR) family, the platelet-derived growth factor receptor (PDGFR) family, as well as Src and Flt-3 kinases. The compound was identified during a lead optimization program for small-molecule inhibitors of angiogenesis and has since undergone extensive clinical investigation for the treatment of various solid tumors, and in patients with the debilitating lung disease idiopathic pulmonary fibrosis (IPF). Recent clinical evidence from phase III studies has shown that nintedanib has significant efficacy in the treatment of NSCLC, ovarian cancer, and IPF. This review article provides a comprehensive summary of the preclinical and clinical research and development of nintedanib from the initial drug discovery process to the latest available clinical trial data.

Careless talk costs lives: fibroblast growth factor receptor signalling and the consequences of pathway malfunction

Since its discovery 40 years ago, fibroblast growth factor (FGF) receptor (FGFR) signalling has been found to regulate fundamental cellular behaviours in a wide range of cell types. FGFRs regulate development, homeostasis, and repair and are implicated in many disorders and diseases; and indeed, there is extensive potential for severe consequences, be they developmental, homeostatic, or oncogenic, should FGF-FGFR signalling go awry, so careful control of the pathway is critically important. In this review, we discuss the recent developments in the FGF field, highlighting how FGFR signalling works in normal cells, how it can go wrong, how frequently it is compromised, and how it is being targeted therapeutically.

Reducing lung function decline in patients with idiopathic pulmonary fibrosis: potential of nintedanib

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fibrotic lung disease with no clear etiology and a paucity of therapeutic options. Nintedanib (previously known as BIBF 1120) is a tyrosine kinase receptor antagonist which inhibits a number of key receptors, including those for platelet derived growth factor (PDGF), vascular endothelial growth factor (VEGF), and fibroblast growth factor (FGF). These growth factors are profibrotic and each has been investigated as a potential standalone therapeutic target in IPF. Simultaneous inhibition of these receptors, with an analog of nintedanib, has proved to be effective in experimental animal models of pulmonary fibrosis. This observation, together with extensive safety and pharmacokinetic data from studies of nintedanib in malignancy, paved the way for the clinical development of this drug in IPF. The Phase IIb TOMORROW trial demonstrated that treatment with nintedanib may potentially slow decline in lung function, decrease the frequency of acute exacerbations, and improve quality of life in patients with IPF. While these observations are drawn from a single clinical trial, taken together with the preclinical data they suggest that nintedanib may yet become an important therapeutic option for individuals with IPF. The results of ongoing parallel, international, multicenter Phase III clinical trials are therefore eagerly awaited.