Riociguat for idiopathic interstitial pneumonia-associated pulmonary hypertension (RISE-IIP): a randomised, placebo-controlled phase 2b study

Soluble guanylyl cyclase stimulators and activators: Promising drugs for the treatment of hypertension?

Nitric oxide (NO)-stimulated cyclic guanosine monophosphate (cGMP) is a key regulator of cardiovascular health, as NO-cGMP signalling is impaired in diseases like pulmonary hypertension, heart failure and chronic kidney disease. The development of NO-independent sGC stimulators and activators provide a novel therapeutic option to restore altered NO signalling. sGC stimulators have been already approved for the treatment of pulmonary arterial hypertension (PAH), chronic thromboembolic pulmonary hypertension (CTEPH), and chronic heart failure (HFrEF), while sGC activators are currently in phase-2 clinical trials for CKD. The best characterized effect of increased cGMP via the NO-sGC-cGMP pathway is vasodilation. However, to date, none of the sGC agonists are in development for hypertension (HTN). According to WHO, the global prevalence of uncontrolled HTN continues to rise, contributing significantly to cardiovascular mortality. While there are effective antihypertensive treatments, many patients require multiple drugs, and some remain resistant to all therapies. Thus, in addition to improved diagnosis and lifestyle changes, new pharmacological strategies remain in high demand. In this review we explore the potential of sGC stimulators and activators as novel antihypertensive agents, starting with the overview of NO-sGC-cGMP signalling, followed by potential mechanisms by which the increase in cGMP may regulate vascular tone and BP. These effects may encompass not only acute vasodilation, but also mid-term and chronic effects, such as the regulation of salt and water balance, as well as mitigation of vascular ageing and remodelling. The main section summarizes the preclinical and clinical evidence supporting the BP-lowering efficacy of sGC agonists.

Shining a spotlight on pulmonary hypertension associated with interstitial lung disease care: The latest advances in diagnosis and treatment

Pulmonary hypertension associated with interstitial lung disease (PH-ILD) is a complex condition in which 2 consequential diseases interact and increase negative outcomes. Although the pathophysiologic mechanisms of PH-ILD are not yet well understood, the pronounced effect on functional status, supplemental oxygen requirements, health care resource utilization, and mortality that frequently accompany this diagnosis are well documented. A critical feature that complicates pathophysiologic understanding of PH-ILD is that progression of the pulmonary vascular disease does not always appear to be driven by the underlying lung disease. As PH-ILD is a progressive disease, early recognition and treatment initiation have the potential to delay the increased burden it creates. Historically, therapeutic development within pulmonary hypertension has concentrated on pulmonary arterial hypertension (PAH). However, PH-ILD and PAH are categorically distinct-belonging to distinct PH groups owing to differing pathophysiological mechanisms and therapeutic implications. PAH and PH-ILD may have numerous similarities; however, when PAH therapies have been studied in patients with PH-ILD, inconclusive efficacy (bosentan, sildenafil, tadalafil, iloprost) and at times deleterious safety findings (riociguat, ambrisentan) have been observed. Despite the paucity of evidence to support PAH therapy use in this patient population, widespread off-label use of PAH therapies arose as a result of a historical lack of PH-ILD-approved treatment. Recently, inhaled treprostinil-a prostacyclin analog-has become the first therapy approved for treatment of PH-ILD. In the phase 3 INCREASE trial, inhaled treprostinil was effective in improving 6-minute walk distance (the primary endpoint; P < 0.001) as well as N-terminal pro-B-type natriuretic peptide levels (P < 0.001). The approval of inhaled treprostinil in 2022 facilitates evidence-based therapeutic management. In addition, the 7th World Symposium on Pulmonary Hypertension has recently published an extensive summary of clinical research to date in PH-ILD. The proceedings from the 7th World Symposium on Pulmonary Hypertension provide timely recommendations for investigation of PH-ILD and a framework for assessing treatment needs. The therapeutic landscape advances are poised to transform PH-ILD care and improve outcomes for patients with PH-ILD.

Pathology of idiopathic pulmonary fibrosis with particular focus on vascular endothelium and epithelial injury and their therapeutic potential

Idiopathic pulmonary fibrosis (IPF) remains a challenging disease with no drugs available to change the trajectory. It is a condition associated with excessive and highly progressive scarring of the lungs with remodelling and extracellular matrix deposition. It is a highly "destructive" disease of the lungs. The diagnosis of IPF is challenging due to continuous evolution of the disease, which also makes early interventions very difficult. The role of vascular endothelial cells has not been explored in IPF in great detail. We do not know much about their contribution to arterial or vascular remodelling, extracellular matrix changes and contribution to pulmonary hypertension and lung fibrosis in general. Endothelial to mesenchymal transition appears to be central to such changes in IPF. Similarly, for epithelial changes, the process of epithelial to mesenchymal transition seem to be the key both for airway epithelial cells and type-2 pneumocytes. We focus here on endothelial and epithelial cell changes and its contributions to IPF. In this review we revisit the pathology of IPF, mechanistic signalling pathways, clinical definition, update on diagnosis and new advances made in treatment of this disease. We discuss ongoing clinical trials with mode of action. A multidisciplinary collaborative approach is needed to understand this treacherous disease for new therapeutic targets.

Shifting Paradigms in the Management of Pulmonary Hypertension

Pulmonary arterial hypertension (PAH) is a long-term condition characterised by increased resistance to blood flow in the pulmonary circulation. The disease has a progressive course and is associated with a poor prognosis. Without treatment, PAH is associated with mortality in <3 years. Over the past decade, many advances have been made in revising the haemodynamic definition, clinical classification, risk calculation score, treatment options etc. Suggestions from the Sixth World Symposium on Pulmonary Hypertension were incorporated into a literature review that was included in the European Society of Cardiology/European Respiratory Society (ESC/ERS)’s most recent iteration of their guidelines in 2022. The traditional cut-off for pulmonary hypertension (PH), i.e., mean pulmonary artery pressure (mPAP) >25 mm Hg, has been challenged by observational cohort studies, which have shown poor outcomes for values of 21–24 mmHg; the new consensus is that PH is defined at mPAP >20 mm Hg. Although the gold standard for diagnosis and the major source of therapy guidance continues to be right cardiac catheterisation, echocardiography remains the initial test of choice. A multidisciplinary approach is highly recommended when treating PH patients and careful evaluation of patients will aid in proper diagnosis and prognosis. Pharmacotherapy for PAH has seen a paradigm shift with the successful use of newer agents in more extensive, longer and more inclusive trials driven by hard endpoints. Macitentan, selexipag and riociguat are three oral agents that have shown astounding success in PAH randomised studies in the past decade. Upfront combination therapy with two agents is now becoming the norm (following the AMBITION, OPTIMA and ITALY trials) and the momentum is shifting towards triple therapy as for essential hypertension. More recently, inhaled treprostinil was shown to improve exercise capacity in PH associated with interstitial lung disease in the phase III INCREASE study and has been granted regulatory approval for World Health Organization group 3 PH. A new class of drug, sotatercept (a tumour growth factor-β signalling inhibitor), has also been recently approved by the Food and Drugs Administration for management of PAH based on positive results from the phase III STELLAR study. Pulmonary artery denervation and balloon pulmonary angioplasty have emerged as viable alternatives in PH that are resistant to drug therapy. This article aims to summarise the key changes and recent advances in diagnosis and managing PH in general, with an emphasis on certain subgroups.

Inhaled Nitric Oxide in Fibrotic Lung Disease: A Randomized, Double-Blind, Placebo-controlled Trial

Rationale: Inhaled nitric oxide (iNO) has been shown to result in benefits in moderate to vigorous physical activity (MVPA) in patients with fibrotic interstitial lung disease (f-ILD) receiving supplemental oxygen in two independent trials. Objective: This phase III randomized, double-blind, placebo-controlled study sought to validate the benefit of ambulatory iNO in patients with f-ILD requiring supplemental oxygen. Methods: Patients with f-ILD receiving supplemental long-term oxygen were randomized in a 1:1 fashion to iNO at 45 μg/kg ideal body weight per hour or placebo for 16 weeks. The primary outcome was the change from baseline to Week 16 in MVPA assessed by accelerometry. Secondary outcomes included overall activity, 6-minute-walk distance and patient-reported outcomes. Results: 145 patients were enrolled; 75 were assigned to receive iNO and 70 placebo. The changes from baseline in MVPA at 16 weeks were -9.2 min/d (standard error, 3.51) in the iNO45 group and -3.7 min/d (3.76) in the placebo group (difference, 5.5; P = 0.265). No statistically significant differences between the two treatment arms were found for any of the secondary outcomes. A subgroup analysis of patients with an intermediate or high probability of pulmonary hypertension on echocardiography did not demonstrate any benefit. The most common adverse events reported were respiratory tract infections, but the therapy was generally very well tolerated. Conclusions: There was no demonstrable benefit to iNO in patients with f-ILD receiving supplemental oxygen in daily physical activity assessed by actigraphy, a potential novel clinical trial endpoint. Clinical trial registered with www.clinicaltrials.gov (NCT03267108).

Vascular involvement in idiopathic pulmonary fibrosis

Background

Idiopathic pulmonary fibrosis (IPF) is a chronic, fibrosing and progressive interstitial lung disease of unknown aetiology with a pathogenesis still partly unknown. Several microvascular and macrovascular abnormalities have been demonstrated in the pathogenesis of IPF and related pulmonary hypertension (PH), a complication of the disease.

Methods

We carried out a non-systematic, narrative literature review aimed at describing the role of the vasculature in the natural history of IPF.

Results

The main molecular pathogenetic mechanisms involving vasculature (i.e. endothelial-to-mesenchymal transition, vascular remodelling, endothelial permeability, occult alveolar haemorrhage, vasoconstriction and hypoxia) and the genetic basis of vascular remodelling are described. The prevalence and clinical relevance of associated PH are highlighted with focus on the vasculature as a prognostic marker. The vascular effects of current antifibrotic therapies, the role of pulmonary vasodilators in the treatment of disease, and new pharmacological options with vascular-targeted activity are described.

Conclusions

The vasculature plays a key role in the natural history of IPF from the early phases of disease until development of PH in a subgroup of patients, a complication related to a worse prognosis. Pulmonary vascular volume has emerged as a novel computed tomography finding and a predictor of mortality, independent of PH. New pharmacological options with concomitant vascular-directed activity might be promising in the treatment of IPF.

Soluble GC stimulators and activators: Past, present and future

The discovery of soluble GC (sGC) stimulators and sGC activators provided valuable tools to elucidate NO-sGC signalling and opened novel pharmacological opportunities for cardiovascular indications and beyond. The first-in-class sGC stimulator riociguat was approved for pulmonary hypertension in 2013 and vericiguat very recently for heart failure. sGC stimulators enhance sGC activity independent of NO and also act synergistically with endogenous NO. The sGC activators specifically bind to, and activate, the oxidised haem-free form of sGC. Substantial research efforts improved on the first-generation sGC activators such as cinaciguat, culminating in the discovery of runcaciguat, currently in clinical Phase II trials for chronic kidney disease and diabetic retinopathy. Here, we highlight the discovery and development of sGC stimulators and sGC activators, their unique modes of action, their preclinical characteristics and the clinical studies. In the future, we expect to see more sGC agonists in new indications, reflecting their unique therapeutic potential.

Efficacy, safety, and pharmacokinetics of inhaled treprostinil in Japanese patients with pulmonary hypertension associated with interstitial lung disease

BACKGROUND

The INCREASE trial, conducted in the United States, showed that inhaled treprostinil improved exercise capacity in pulmonary hypertension associated with interstitial lung disease (PH-ILD). However, hemodynamic and pharmacokinetic measurements were not performed in the trial. The objective of this trial was to evaluate the efficacy on hemodynamics and exercise capacity, safety, and pharmacokinetics (PK) of inhaled treprostinil in Japanese patients with PH-ILD.

METHODS

This trial was a multicenter, non-randomized, open-label, single-arm trial of patients with PH-ILD. Inhaled treprostinil was administered at 3 breaths (18 μg)/session four times daily, and the dose was gradually increased to a maximum of 12 breaths (72 μg)/session. The primary endpoints were the change of pulmonary vascular resistance index (PVRI) and peak 6-min walking distance (6MWD) from baseline to week 16. Endpoints also included other efficacy parameters, safety, and PK.

RESULTS

Twenty patients received inhaled treprostinil. At week 16, PVRI decreased from baseline by -40.1% (95% CI, -53.1 to -27.2) and peak 6MWD increased by 13.0 m (95% CI, -15.0 to 49.0). The most frequently reported adverse events related with treprostinil were cough, malaise and blood pressure decreased. PK was similar to those in pulmonary arterial hypertension (PAH) patients.

CONCLUSIONS

Treatment with inhaled treprostinil using the same dosing regimen as in the INCREASE trial resulted in improvements in hemodynamics and exercise capacity with a favorable tolerability and safety profile in Japanese patients with PH-ILD.

Evidence and unresolved questions in pulmonary hypertension: Insights from the 5th French Pulmonary Hypertension Network Meeting

Pulmonary hypertension (PH) continues to present significant challenges to the medical community, both in terms of diagnosis and treatment. The advent of the updated 2022 European Society of Cardiology (ESC) and European Respiratory Society (ERS) guidelines has introduced pivotal changes that reflect the rapidly advancing understanding of this complex disease. These changes include a revised definition of PH, updates to the classification system, and treatment algorithm. While these guidelines offer a critical framework for the management of PH, they have also sparked new discussions and questions. The 5th French Pulmonary Hypertension Network Meeting (Le Kremlin-Bicêtre, France, 2023), addressed these emergent questions and fostering a deeper understanding of the disease's multifaceted nature. These discussions were not limited to theoretical advancements but extended into the practical realms of patient management, highlighting the challenges and opportunities in applying the latest guidelines to clinical practice.

Treatment algorithm for pulmonary arterial hypertension

Pulmonary arterial hypertension leads to significant impairment in haemodynamics, right heart function, exercise capacity, quality of life and survival. Current therapies have mechanisms of action involving signalling via one of four pathways: endothelin-1, nitric oxide, prostacyclin and bone morphogenetic protein/activin signalling. Efficacy has generally been greater with therapeutic combinations and with parenteral therapy compared with monotherapy or nonparenteral therapies, and maximal medical therapy is now four-drug therapy. Lung transplantation remains an option for selected patients with an inadequate response to therapies.

Pulmonary Hypertension in Interstitial Lung Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Pulmonary hypertension (PH) is a key complication in interstitial lung disease (ILD), with recent therapeutic advances.

RESEARCH QUESTION

What are the diagnostic evaluation, epidemiologic features, associated factors, prognostic significance, and outcome measures in interventional trials for PH in patients with ILD in the current literature?

STUDY DESIGN AND METHODS

The Ovid MEDLINE, Embase, and CENTRAL databases were searched for original research evaluating PH in participants with ILD of any cause. The definition of PH was based on the investigators' criteria.

RESULTS

Three hundred two studies were included, with varying diagnostic evaluations used to define PH. Commonly used diagnostic tests were right heart catheterization (56%) and transthoracic echocardiography (50%). The pooled prevalence for PH in general populations with ILD was 36% (95% CI, 30%-42%) using right heart catheterization and 34% (95% CI, 29%-38%) using transthoracic echocardiography. Lower diffusion capacity of the lungs for carbon monoxide, worse oxygenation status, reduced exercise capacity, increased pulmonary artery to aorta ratio and pulmonary artery diameter, and elevated serum brain natriuretic peptide consistently were associated with the presence of PH in at least 60% of reported studies. The presence of PH was associated with increased symptom burden and worse prognosis. Outcome measures in interventional trials of PH in ILD focused on changes in pulmonary vascular hemodynamics and 6-min walk distance.

INTERPRETATION

PH is a common complication in ILD with significant health impacts. A standardized definition with prospective evaluation of risk-stratified assessments for PH using identified associated risk factors is warranted. Our findings provide an evidence base for validation as surrogate end points in future PH interventional trials in ILD.

TRIAL REGISTRY

International Prospective Register of Systematic Reviews; No.: CRD42021255394; URL: https://www.crd.york.ac.uk/prospero/.

Pulmonary hypertension associated with lung diseases

Pulmonary hypertension (PH) associated with chronic lung disease (CLD) is both common and underrecognised. The presence of PH in the setting of lung disease has been consistently shown to be associated with worse outcomes. Recent epidemiological studies have advanced understanding of the heterogeneity of this patient population and shown that defining both the specific type of CLD as well as the severity of PH (i.e. deeper phenotyping) is necessary to inform natural history and prognosis. A systematic diagnostic approach to screening and confirmation of suspected PH in CLD is recommended. Numerous uncontrolled studies and one phase 3 randomised, controlled trial have suggested a benefit in treating PH in some patients with CLD, specifically those with fibrotic interstitial lung disease (ILD). However, other studies in diseases such as COPD-PH showed adverse outcomes with some therapies. Given the expanding list of approved pharmacological treatments for pulmonary arterial hypertension, developing a treatment algorithm for specific phenotypes of CLD-PH is required. This article will summarise existing data in COPD, ILD and other chronic lung diseases, and provide recommendations for classification of CLD-PH and approach to the diagnosis and management of these challenging patients.

COPD associated pulmonary hypertension: A post hoc analysis of the PERFECT study

The PERFECT study, a randomized, controlled, double-blind study of inhaled treprostinil in patients with COPD and associated pulmonary hypertension (PH-COPD) was a negative trial that was terminated early. The reason(s) for the negative outcome remains uncertain. A post hoc analysis of data from the PERFECT study was undertaken to identify adverse responders and possibly potential responders. The goal was also to provide insight into phenotypes for possible inclusion and exclusion in future PH-COPD clinical trials. An adverse response on active treatment was seen in 36.4% (24/66) of the subjects compared to 27.6% (16/58) on placebo. There was no evidence to suggest that hyperinflation, bronchospasm, or occult heart failure played any role in the untoward outcomes of the study. The patients who died during the study all had baseline diffusing capacity for carbon monoxide ≤25% of predicted. Evidence of a potential response was seen in 10.6% (7/66) of the patients who received inhaled treprostinil. Patients who had evidence of a treatment response had a baseline mean pulmonary artery pressure of ≥40 mmHg and a forced expiratory volume in the first second of ≥40%. Change in N-terminal prohormone of brain natriuretic peptide did not predict clinical response. This post hoc analysis provides information that may potentially enable improved selection of patients for future therapeutic trials in PH-COPD. These analyses are post hoc, observational, and exploratory. The thresholds defining the spectrum of responders are preliminary and may require further refinement and validation in future studies.

Converging Pathways: A Review of Pulmonary Hypertension in Interstitial Lung Disease

Pulmonary hypertension (PH) in interstitial lung disease (ILD) is relatively common, affecting up to 50% of patients with idiopathic pulmonary fibrosis (IPF). It occurs more frequently in advanced fibrotic ILD, although it may also complicate milder disease and carries significant clinical implications in terms of morbidity and mortality. Key pathological processes driving ILD-PH include hypoxic pulmonary vasoconstriction and pulmonary vascular remodelling. While current understanding of the complex cell signalling pathways and molecular mechanisms underlying ILD-PH remains incomplete, there is evidence for an interplay between the disease pathogenesis of fibrotic ILD and PH, with interest in the role of the pulmonary endothelium in driving pulmonary fibrogenesis more recently. This review examines key clinical trials in ILD-PH therapeutics, including recent research showing promise for the treatment of both ILD-PH and the underlying pulmonary fibrotic process, further supporting the hypothesis of interrelated pathogenesis. Other important management considerations are discussed, including the value of accurate phenotyping in ILD-PH and the success of the "pulmonary vascular" phenotype. This article highlights the close and interconnected nature of fibrotic ILD and PH disease pathogenesis, a perspective likely to improve our understanding and therapeutic approach to this complex condition in the future.

Evidence from recent clinical trials in fibrotic interstitial lung diseases

PURPOSE OF REVIEW

Idiopathic pulmonary fibrosis (IPF) is the prototype of fibrosing interstitial lung diseases. It is mirrored by progressive pulmonary fibrosis (PPF), an umbrella term which characterizes disease behavior of various fibrotic interstitial lung diseases with irreversible progression, accounting for loss of lung function, exercise intolerance and respiratory failure leading to early mortality. Pirfenidone and nintedanib halve the decline in lung function but do not halt disease progression.

RECENT FINDINGS

Since the publication in 2014 of pivotal pirfenidone and nintedanib studies, a number of clinical trials were conducted, many of them did not reach their primary endpoints. In IPF, promising phase 2 trials were followed by large phase 3 trials that did not confirm a favorable efficacy to tolerability favorable profile, including those with ziritaxestat, an autotaxin-1 inhibitor, zinpentraxin-alpha (human recombinant pentraxin-2), and the monoclonal antibody pamrevlumab targeting connective tissue growth factor. Nevertheless, newer compounds that hold promise are currently being evaluated in phase 3 or phase 2b randomized controlled trials, including: nerandomilast, a preferential phosphodiesterase 4B inhibitor; admilparant, a lysophosphatidic acid receptor antagonist; inhaled treprostinil, a prostacyclin agonist; and bexotegrast, a dual-selective inhibitor of αvβ6 and αvβ1 integrins. Nerandomilast, admilparant, inhaled treprostinil, and inhaled AP01 (pirfenidone), are currently studied in patients with PPF.

SUMMARY

Despite recent frustrating negative results, there is a growing portfolio of candidate drugs developed in both IPF and PPF.

Contemporary Treatment of Pulmonary Arterial Hypertension: A U.S. Perspective

Pulmonary arterial hypertension (PAH) is a complex fatal condition that requires aggressive treatment with close monitoring. Significant progress has been made over the last three decades in the treatment of PAH, but, despite this progress, survival has remained unacceptably low. In the quest to improve survival, therapeutic interventions play a central role. In the last few years, there have been remarkable attempts to identify novel treatments. Finally, we have had a breakthrough with the discovery of the fourth treatment pathway in PAH. Activin signaling inhibition distinguishes itself as a potential antiproliferative intervention as opposed to the traditional therapies, which mediate their effect primarily by vasodilatation. With this novel treatment pathway, we stand at an important milestone with an exciting future ahead and the natural question of when to use an activin signaling inhibitor for the treatment of PAH. In this state-of-the-art review, we focus on the placement of this novel agent in the PAH treatment paradigm, based on the available evidence, with special focus on the U.S. patient population. This review also provides an expert opinion of the current treatment algorithm in important subgroups of patients with comorbidities from the U.S. perspective.

Selexipag for patients with pulmonary hypertension associated with lung disease: A preliminary study

BACKGROUND

Pulmonary arterial hypertension (PAH)-specific therapies are generally ineffective in patients with pulmonary hypertension associated with lung disease (PH-LD). The aim of this preliminary study was to evaluate the potential efficacy of selexipag, titrated according to individual tolerance, in patients with PH-LD.

METHODS

Consecutive patients diagnosed with PH-LD between October 2016 and March 2019, who received selexipag treatment, were retrospectively evaluated. Specific parameters, including changes in hemodynamic parameters, 6-min walk distance (6MWD), and partial pressure of atrial oxygen/fraction of inspiratory oxygen (PaO2/FiO2) were evaluated. Patients whose 6MWD improved ≥20 m were defined as responders.

RESULTS

Eight patients with PH-LD were included, comprising four with chronic obstructive pulmonary disease (COPD), two with interstitial lung disease (ILD) related to rheumatoid arthritis, one with ILD related to systemic sclerosis, and one with pulmonary Langerhans cell histiocytosis. No statistically significant improvements in hemodynamic parameters and 6MWD were noted following selexipag treatment. However, four patients showed improvements in 6MWD ≥20 m at follow-up and were considered responders. They had a higher body mass index (BMI) and lower PaO2/FiO2 at baseline than non-responders (p = 0.02 and p = 0.04, respectively). No Grade 3 or 4 adverse events were observed.

CONCLUSIONS

Selexipag was effective in half of the PH-LD cases, emphasizing higher BMI and lower PaO2/FiO2 as possible indicators for favorable response. Since selexipag starting at a low dose with subsequent titration may reduce the risk of early adverse events, it can be considered a treatment option for PH-LD. Further large-scale studies are warranted to confirm these findings.

A PrOsPective Cohort Study on Interstitial Lung Disease-Associated Pulmonary Hypertension with a ParticulaR Focus on the Subset with Pulmonary Arterial Hypertension Features (POPLAR Study)

INTRODUCTION

The pathogenesis and clinical profiles of patients with pulmonary hypertension (PH) associated with interstitial lung disease (ILD-PH) are poorly understood. Whether and to what extent pulmonary arterial hypertension (PAH)-specific therapy improves hemodynamic and outcome in ILD-PH are also unknown.

STUDY OBJECTIVE

This study aims to clarify the characteristics, clinical course and response to PAH-specific therapy of ILD and/or PH by enrolling three unique subsets: PAH, ILD-PH, and ILD.

METHODS

The proposed study is a retrospective and prospective, multi-centre, observational cohort study of patients treated at any of three university hospitals in the Hokkaido region of Japan who have any one of the following: PAH; ILD-PH with or without PAH features; or ILD without PH. We aim to enrol 250 patients in total. For the retrospective observation period, data obtained after 1 January 2010, will be analysed, and the prospective observation period will be 1 year. We will compare the clinical data of patients with ILD-PH with those of patients with PAH and those of patients with ILD without PH in the real-world clinical setting. In addition, within the cohort of patients with ILD-PH, we will explore the subset with "ILD-PH with PAH features" and compare the response to PAH-specific therapy with that of PAH. The primary outcome will be the change in pulmonary vascular resistance from first treatment to follow-up in patients with PAH and ILD-PH with PAH features (excluding ILD-PH without PAH feature and ILD-no-PH for the primary outcome). The exploratory outcomes will include analyses of PH-associated biomarkers, right ventricular function and patient-reported outcomes.

RESULTS

This is a protocol article and the results will be presented after data collection is completed.

CONCLUSION

The POPLAR study will provide data that help better understand the pathophysiology of ILD-PH and improve the quality of life and outcome of patients with PH and/or ILD.

TRIAL REGISTRATION

Japan Registry of Clinical Trials: jRCT1010230018.

A Case of Interstitial Lung Disease-Related Pulmonary Hypertension Successfully Treated with Inhaled Iloprost

Pulmonary hypertension (PH) associated with interstitial lung disease (ILD) (PH-ILD) significantly worsens clinical symptoms and survival, with no effective treatment available. This case report presents the successful treatment of PH-ILD with inhaled iloprost in a patient with idiopathic pulmonary fibrosis (IPF). The patient, a 68-year-old female, was diagnosed with IPF in 2018 and was maintained on pirfenidone. She experienced stable disease until March 2023, when she developed progressive exertional dyspnea, despite stability indicated by a computed tomography (CT) scan, without progression. Transthoracic echocardiography (TTE) and right heart catheterization (RHC) confirmed PH-ILD with a mean pulmonary artery pressure (mPAP) of 43 mmHg. Due to the ineffectiveness of sildenafil and a CT scan indicating stable IPF, a repeat RHC was performed, which showed a worsening of PH (mPAP 62 mmHg). Consequently, inhaled iloprost, at a dosage of 10 mcg every eight hours, was added to the existing antifibrotic agent. After two months, the patient experienced reduced exertional dyspnea and home oxygen requirements. By the seventh month, pulmonary function tests, the six-minute walk test, and RHC parameters (mPAP 37 mmHg) showed marked improvements. This case suggests that inhaled iloprost may be beneficial for managing PH-ILD. Further research is needed to confirm the efficacy of iloprost in PH-ILD treatment.

Pharmacological treatment in Idiopathic Pulmonary Fibrosis: current issues and future perspectives

Idiopathic pulmonary fibrosis (IPF) represents a fibrotic interstitial lung disease characterized by uncertain etiology and poor prognosis. Over the years, the path to effective treatments has been marked by a series of advances and setbacks. The introduction of approved antifibrotic drugs, pirfenidone and nintedanib, marked a pivotal moment in the management of IPF. However, despite these advances, these drugs are not curative, although they can slow the natural progression of the disease. The history of drug therapy for IPF goes together with the increased understanding of the pathogenic mechanisms underlying the disease. Based on that, current research efforts continue to explore new therapies, possible personalized treatment strategies, drug combinations, and potential biomarkers for diagnosis and prognosis. In this review, we outline the route that led to the discover of the first effective therapies, ongoing clinical trials, and future directions in the search for more effective treatments.

Pirfenidone and nintedanib attenuates pulmonary artery endothelial and smooth muscle cells transformations induced by IL-11

Idiopathic pulmonary fibrosis (IPF) associated to pulmonary hypertension (PH) portends a poor prognosis, characterized by lung parenchyma fibrosis and pulmonary artery remodeling. Serum and parenchyma levels of Interleukin 11 (IL-11) are elevated in IPF-PH patients and contributes to pulmonary artery remodeling and PH. However, the effect of current approved therapies against IPF in pulmonary artery remodeling induced by IL-11 is unknown. The aim of this study is to analyze the effects of nintedanib and pirfenidone on pulmonary artery endothelial and smooth muscle cell remodeling induced by IL-11 in vitro. Our results show that nintedanib (NTD) and pirfenidone (PFD) ameliorates endothelial to mesenchymal transition (EnMT), pulmonary artery smooth muscle cell to myofibroblast-like transformation and pulmonary remodeling in precision lung cut slices. This study provided also evidence of the inhibitory effect of PFD and NTD on IL-11-induced endothelial and muscle cells proliferation and senescence. The inhibitory effect of these drugs on monocyte arrest and angiogenesis was also studied. Finally, we observed that IL-11 induced canonical signal transducer and activator of transcription 3 (STAT3) and non-canonical mitogen-activated protein kinase 1/2 (ERK1/2) phosphorylation, but, PFD and NTD only inhibited ERK1/2 phosphorylation. Therefore, this study provided evidence of the inhibitory effect of NTD and PFD on markers of pulmonary artery remodeling induced by IL-11.

Therapeutic Potential of Treprostinil Inhalation Powder for Patients with Pulmonary Arterial Hypertension: Evidence to Date

Pulmonary arterial hypertension (PAH) is a complex and incurable disease for which pulmonary vasodilators remain the core therapy. Of the three primary pathways that vasodilators target, the prostacyclin pathway was the earliest to be used and currently has the largest number of modalities for drug delivery. Inhaled treprostinil has been introduced as a treatment option in PAH and, more recently, pulmonary hypertension (PH) due to interstitial lung disease (PH-ILD), and the earlier nebulized form has been joined by a dry powder form allowing for more convenient use. In this review, we discuss inhaled treprostinil, focusing on the dry powder inhalation (DPI) formulation, and explore its dosing, applications, and evidence to support patient tolerance and acceptance. Recent trials underpinning the evidence for use of inhaled treprostinil and the most recent developments concerning the drug are discussed. Finally, the review looks briefly into premarket formulations of inhaled treprostinil and relevant early studies suggesting efficacy in PAH treatment.

Bioinformatics analysis of hypoxia associated genes and inflammatory cytokine profiling in COPD-PH

Pulmonary hypertension (PH) in chronic obstructive pulmonary disease (COPD) is associated with worse clinical outcomes and decreased survival rates. In absence of disease specific diagnostic/therapeutic targets and unclear pathophysiology, there is an urgent need for the identification of potential genetic/molecular markers and disease associated pathways. The present study aims to use a bioinformatics approach to identify and validate hypoxia-associated gene signatures in COPD-PH patients. Additionally, hypoxia-related inflammatory profile is also explored in these patients. Microarray dataset obtained from the Gene Expression Omnibus repository was used to identify differentially expressed genes (DEGs) in a hypoxic PH mice model. The top three hub genes identified were further validated in COPD-PH patients, with chemokine (C-X-C motif) ligand 9 (CXCL9) and CXCL12 showing significant changes in comparison to healthy controls. Furthermore, multiplexed analysis of 10 inflammatory cytokines, tumor necrosis factor alpha (TNF-α), transforming growth factor β (TGF-β), interleukin 1-beta (IL-1β), IL-4, IL-5, IL-6, IL-13, IL-17, IL-18 and IL-21 was also performed. These markers showed significant changes in COPD-PH patients as compared to controls. They also exhibited the ability to differentially diagnose COPD-PH patients in comparison to COPD. Additionally, IL-6 and IL-17 showed significant positive correlation with systolic pulmonary artery pressure (sPAP). This study is the first report to assess the levels of CXCL9 and CXCL12 in COPD-PH patients and also explores their link with the inflammatory profile of these patients. Our findings could be extended to better understand the underlying disease mechanism and possibly used for tailoring therapies exclusive for the disease.

Phase 1 Study of MK-5475, an Inhaled Soluble Guanylate Cyclase Stimulator, in Participants with Pulmonary Hypertension Associated with Chronic Obstructive Pulmonary Disease

Purpose

This phase 1 study (NCT04370873) evaluated safety and pharmacokinetics/pharmacodynamics (PK/PD) of MK-5475 in participants with pulmonary hypertension associated with COPD (PH-COPD).

Methods

Eligible participants were 40-80 years old with COPD (FEV1/FVC <0.7; FEV1 >30% predicted) and PH (mean pulmonary arterial pressure ≥25 mmHg). Participants were randomized 2:1 to MK-5475 or placebo via dry-powder inhaler once daily for 7 days in Part 1 (360 µg) or 28 days in Part 2 (380 µg). Safety was assessed by adverse events (AEs) and arterial blood oxygenation. Part-2 participants had pulmonary vascular resistance (PVR; primary PD endpoint) and pulmonary blood volume (PBV; secondary PD endpoint) measured at baseline and Day 28. A non-informative prior was used to calculate posterior probability (PP) that the between-group difference (MK-5475 - placebo) in mean percent reduction from baseline in PVR was less than -15%.

Results

Nine participants were randomized in Part 1, and 14 participants in Part 2. Median age of participants (86.4% male) was 68.5 years (41-77 years); 95.5% had moderate-to-severe COPD. Incidences of AEs were comparable between MK-5475 and placebo: overall (5/14 [36%] versus 5/8 [63%]), drug-related (1/14 [7%] versus 2/8 [25%]), and serious (1/14 [7%] versus 1/8 [13%]). MK-5475 caused no meaningful changes in arterial blood oxygenation or PBV. MK-5475 versus placebo led to numerical improvements from baseline in PVR (-21.2% [95% CI: -35.4, -7.0] versus -5.4% [95% CI: -83.7, 72.9]), with between-group difference in PVR less than -15% and calculated PP of 51%.

Conclusion

The favorable safety profile and numerical reductions in PVR observed support further clinical development of inhaled MK-5475 for PH-COPD treatment.

Interstitial Lung Disease: A Review

Importance

Interstitial lung disease (ILD) consists of a group of pulmonary disorders characterized by inflammation and/or fibrosis of the lung parenchyma associated with progressive dyspnea that frequently results in end-stage respiratory failure. In the US, ILD affects approximately 650 000 people and causes approximately 25 000 to 30 000 deaths per year.

Observations

The most common forms of ILD are idiopathic pulmonary fibrosis (IPF), which accounts for approximately one-third of all cases of ILD, hypersensitivity pneumonitis, accounting for 15% of ILD cases, and connective tissue disease (CTD), accounting for 25% of ILD cases. ILD typically presents with dyspnea on exertion. Approximately 30% of patients with ILD report cough. Thoracic computed tomography is approximately 91% sensitive and 71% specific for diagnosing subtypes of ILDs such as IPF. Physiologic assessment provides important prognostic information. A 5% decline in forced vital capacity (FVC) over 12 months is associated with an approximately 2-fold increase in mortality compared with no change in FVC. Antifibrotic therapy with nintedanib or pirfenidone slows annual FVC decline by approximately 44% to 57% in individuals with IPF, scleroderma associated ILD, and in those with progressive pulmonary fibrosis of any cause. For connective tissue disease-associated ILD, immunomodulatory therapy, such as tocilizumab, rituximab, and mycophenolate mofetil, may slow decline or even improve FVC at 12-month follow-up. Structured exercise therapy reduces symptoms and improves 6-minute walk test distance in individuals with dyspnea. Oxygen reduces symptoms and improves quality of life in individuals with ILD who desaturate below 88% on a 6-minute walk test. Lung transplant may improve symptoms and resolve respiratory failure in patients with end-stage ILD. After lung transplant, patients with ILD have a median survival of 5.2 to 6.7 years compared with a median survival of less than 2 years in patients with advanced ILD who do not undergo lung transplant. Up to 85% of individuals with end-stage fibrotic ILD develop pulmonary hypertension. In these patients, treatment with inhaled treprostinil improves walking distance and respiratory symptoms.

Conclusions and Relevance

Interstitial lung disease typically presents with dyspnea on exertion and can progress to respiratory failure. First-line therapy includes nintedanib or pirfenidone for IPF and mycophenolate mofetil for ILD due to connective tissue disease. Lung transplant should be considered for patients with advanced ILD. In patients with ILD, exercise training improves 6-minute walk test distance and quality of life.

The acute effect of inhaled nitric oxide on the exercise capacity of patients with advanced interstitial lung disease: a randomized controlled trial

BACKGROUND

Inhaled nitric oxide (iNO) selectively acts on the pulmonary vasculature of ventilated lung tissue by reducing pulmonary vascular resistance and intrapulmonary shunt. This effect may reduce ventilation/perfusion mismatch and decrease pulmonary hypertension in patients with interstitial lung disease.

METHODS

In a prospective, single-blinded, randomized, placebo-controlled trial, participants with advanced interstitial lung disease, underwent two separate six-minute walk tests (6MWT): one with iNO and the other with a placebo. The primary outcome measured the difference in meters between the distances covered in the two tests. Secondary outcomes included oxygen saturation levels, distance-saturation product, and Borg dyspnea score. A predefined subgroup analysis was conducted for patients with pulmonary hypertension.

RESULTS

Overall, 44 patients were included in the final analysis. The 6MWT distance was similar for iNO treatment and placebo, median 362 m (IQR 265-409) vs 371 m (IQR 250-407), respectively (p = 0.29). Subgroup analysis for patients with pulmonary hypertension showed no difference in 6MWT distance with iNO and placebo, median 339 (256-402) vs 332 (238-403) for the iNO and placebo tests respectively (P=0.50). No correlation was observed between mean pulmonary artery pressure values and the change in 6MWT distance with iNO versus placebo (spearman correlation Coefficient 0.24, P=0.33).

CONCLUSION

In patients with advanced interstitial lung disease, both with and without concurrent pulmonary hypertension, the administration of inhaled nitric oxide failed to elicit beneficial effects on the six-minute walk distance and oxygen saturation. The use of inhaled NO was found to be safe and did not lead to any serious side effects.

TRIAL REGISTRATION

(NCT03873298, MOH_2018-04-24_002331).

Japanese guidelines for the treatment of idiopathic pulmonary fibrosis 2023:Revised edition

Idiopathic pulmonary fibrosis (IPF) is an interstitial lung disease with a poor prognosis and an unknown cause that generally progresses to pulmonary fibrosis and leads to irreversible tissue alteration. The "Guidelines for the treatment of idiopathic pulmonary fibrosis 2017," specializing in the treatment of IPF for the first time in Japan and presenting evidence-based standard treatment methods suited to the state of affairs in Japan, was published in 2017, in line with the 2014 version of "Formulation procedure for Minds Clinical Practice Guidelines." Because new evidence had accumulated, we formulated the "Guidelines for the treatment of Idiopathic Pulmonary Fibrosis 2023 (revised 2nd edition)." While keeping the revision consistent with the ATS/ERS/JRS/ALAT IPF treatment guidelines, new clinical questions (CQs) on pulmonary hypertension were added to the chronic stage, in addition to acute exacerbation and comorbid lung cancer, which greatly affect the prognosis but are not described in the ATS/ERS/JRS/ALAT IPF guidelines. Regarding the advanced stages, we additionally created expert consensus-based advice for palliative care and lung transplantation. The number of CQs increased from 17 in the first edition to 24. It is important that these guidelines be used not only by respiratory specialists but also by general practitioners, patients, and their families; therefore, we plan to revise them appropriately in line with ever-advancing medical progress.

Survival analysis from the INCREASE study in PH-ILD: evaluating the impact of treatment crossover on overall mortality

OBJECTIVE

A post-hoc analysis of the INCREASE trial and its open-label extension (OLE) was performed to evaluate whether inhaled treprostinil has a long-term survival benefit in patients with pulmonary hypertension associated with interstitial lung disease (PH-ILD).

METHODS

Two different models of survival were employed; the inverse probability of censoring weighting (IPCW) and the rank-preserving structural failure time (RPSFT) models both allow construction of a pseudo-placebo group, thereby allowing for long-term survival evaluation of patients with PH-ILD receiving inhaled treprostinil. Time-varying stabilised weights were calculated by fitting Cox proportional hazards models based on the baseline and time-varying prognostic factors to generate weighted Cox regression models with associated adjusted HRs.

RESULTS

In the INCREASE trial, there were 10 and 12 deaths in the inhaled treprostinil and placebo arms, respectively, during the 16-week randomised trial. During the OLE, all patients received inhaled treprostinil and there were 29 and 33 deaths in the prior inhaled treprostinil arm and prior placebo arm, respectively. With a conventional analysis, the HR for death was 0.71 (95% CI 0.46 to 1.10; p=0.1227). Both models demonstrated significant reductions in death associated with inhaled treprostinil treatment with HRs of 0.62 (95% CI 0.39 to 0.99; p=0.0483) and 0.26 (95% CI 0.07 to 0.98; p=0.0473) for the IPCW and RPSFT methods, respectively.

CONCLUSION

Two independent modelling techniques that have been employed in the oncology literature both suggest a long-term survival benefit associated with inhaled treprostinil treatment in patients with PH-ILD.

Vasoactive drugs for the treatment of pulmonary hypertension associated with interstitial lung diseases: a systematic review

OBJECTIVES

Vasoactive drugs have exhibited clinical efficacy in addressing pulmonary arterial hypertension, manifesting a significant reduction in morbidity and mortality. Pulmonary hypertension may complicate advanced interstitial lung disease (PH-ILD) and is associated with high rates of disability, hospitalisation due to cardiac and respiratory illnesses, and mortality. Prior management hinged on treating the underlying lung disease and comorbidities. However, the INCREASE trial of inhaled treprostinil in PH-ILD has demonstrated that PH-ILD can be effectively treated with vasoactive drugs.

METHODS

This comprehensive systematic review examines the evidence for vasoactive drugs in the management of PH-ILD.

RESULTS

A total of 1442 pubblications were screened, 11 RCTs were considered for quantitative synthesis. Unfortunately, the salient studies are limited by population heterogeneity, short-term follow-up and the selection of outcomes with uncertain clinical significance.

CONCLUSIONS

This systematic review underscores the necessity of establishing a precision medicine-oriented strategy, directed at uncovering and addressing the intricate cellular and molecular mechanisms that underlie the pathophysiology of PH-ILD.

PROSPERO REGISTRATION NUMBER

CRD42023457482.

Patient and Therapeutic Profiles of Pulmonary Hypertension in Chronic Lung Diseases in Japan: A Cohort Study Using a Claims Database

INTRODUCTION

Pulmonary hypertension (PH) is often complicated by chronic lung diseases (CLDs) such as chronic obstructive pulmonary disease (COPD) and interstitial lung disease (ILD). Differentiating between PH associated with CLD (group 3 PH) and pulmonary arterial hypertension (PAH) in CLD is often difficult and reporting on the efficacy of PAH-specific therapies is inconsistent as a result of the lack of understanding of the heterogeneity of patients with PH.

METHODS

A retrospective observational cohort study was conducted to understand the baseline characteristics, comorbidities, and treatment profiles of patients with PH in CLD in a real-world setting using a large-scale claims database (Medical Data Vision). Administrative and clinical data for patients admitted to acute-care hospitals in Japan between April 2008 and January 2021 were analyzed.

RESULTS

A total of 115,921 patients with CLD (109,578 with COPD and 6343 with ILD, of whom 569 and 176 had PH, respectively) were analyzed. This study found lower PH diagnosis rates among patients with COPD and patients with ILD than in previous studies. The majority of PH with CLD patients were elderly (mean age 75.7 years) and male (80.81%). Among patients with CLD prescribed PAH-specific therapies (105 patients with COPD; 64 patients with ILD), most received these as monotherapy (COPD, 84.76%; ILD, 75.56%); the most common were phosphodiesterase 5 inhibitors (COPD, 42.70%; ILD, 18.37%), prostacyclins (oral; COPD, 48.31%; ILD, 24.49%), and endothelin receptor antagonists (ERA) (COPD, 8.99%; ILD, 18.37%). Comorbidities (e.g., pulmonary, cardiac, kidney), home oxygen therapy (HOT), and echocardiography (ECHO) were factors associated with the diagnosis of PH.

CONCLUSION

This is the first study using an administrative database that provides real-world data on patients with PH in CLD in Japan. Our results indicate that PH may be misdiagnosed or underdiagnosed in Japan which may lead to suboptimal treatment for patients, and supports the need for further evidence to guide appropriate treatment.

Managing Pulmonary Arterial Hypertension With Cardiopulmonary Comorbidities

Pulmonary arterial hypertension (PAH) and pulmonary hypertension associated with left-sided heart and lung diseases are most commonly easily discriminated and treated accordingly. With the changing epidemiology of PAH, however, a growing proportion of patients at the time of diagnosis present with comorbidities of varying severity. In addition to classical PAH, two distinct phenotypes have emerged: a heart failure with preserved ejection fraction-like phenotype and a lung phenotype. Importantly, the evidence supporting the currently proposed treatment algorithm for PAH has been generated mainly from PAH trials in which patients with cardiopulmonary comorbidities have been underrepresented or excluded. As a consequence, the best therapeutic approach for patients with common PAH with cardiopulmonary comorbidities remains largely unknown and requires further investigation. The present article reviews the relevant literature on the topic and describes the authors' views on the current therapeutic approach for these patients.

Treatment of idiopathic pulmonary fibrosis and progressive pulmonary fibrosis: A position statement from the Thoracic Society of Australia and New Zealand 2023 revision

Idiopathic pulmonary fibrosis (IPF) is a progressive disease leading to significant morbidity and mortality. In 2017 the Thoracic Society of Australia and New Zealand (TSANZ) and Lung Foundation Australia (LFA) published a position statement on the treatment of IPF. Since that time, subsidized anti-fibrotic therapy in the form of pirfenidone and nintedanib is now available in both Australia and New Zealand. More recently, evidence has been published in support of nintedanib for non-IPF progressive pulmonary fibrosis (PPF). Additionally, there have been numerous publications relating to the non-pharmacologic management of IPF and PPF. This 2023 update to the position statement for treatment of IPF summarizes developments since 2017 and reaffirms the importance of a multi-faceted approach to the management of IPF and progressive pulmonary fibrosis.

The nitric oxide-soluble guanylate cyclase-cGMP pathway in pulmonary hypertension: from PDE5 to soluble guanylate cyclase

The nitric oxide (NO)-soluble guanylate cyclase (sGC)-cyclic guanosine monophosphate (cGMP) pathway plays a key role in the pathogenesis of pulmonary hypertension (PH). Targeted treatments include phosphodiesterase type 5 inhibitors (PDE5i) and sGC stimulators. The sGC stimulator riociguat is approved for the treatment of pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH). sGC stimulators have a dual mechanism of action, enhancing the sGC response to endogenous NO and directly stimulating sGC, independent of NO. This increase in cGMP production via a dual mechanism differs from PDE5i, which protects cGMP from degradation by PDE5, rather than increasing its production. sGC stimulators may therefore have the potential to increase cGMP levels under conditions of NO depletion that could limit the effectiveness of PDE5i. Such differences in mode of action between sGC stimulators and PDE5i could lead to differences in treatment efficacy between the classes. In addition to vascular effects, sGC stimulators have the potential to reduce inflammation, angiogenesis, fibrosis and right ventricular hypertrophy and remodelling. In this review we describe the evolution of treatments targeting the NO-sGC-cGMP pathway, with a focus on PH.

Evolution of pulmonary hypertension in interstitial lung disease: a journey through past, present, and future

Interstitial lung diseases (ILD) are a spectrum of disorders often complicated by pulmonary hypertension (PH) in its course. The pathophysiologic mechanism of WHO group 3 PH is different to other forms of PH. The advent of PH is a harbinger for adverse events like mortality and morbidity, implying that the PH component of disease expedites deteriorated clinical outcomes. In fact, WHO group 3 PH due to ILD has the worse prognosis among all groups of PH. Hence, early detection of PH by a comprehensive screening method is paramount. Given considerable overlap in clinical manifestations between ILD and PH, early detection of PH is often elusive. Despite, the treatment of PH due to ILD has been frustrating until recently. Clinical trials utilizing PAH-specific pulmonary vasodilators have been ongoing for years without desired results. Eventually, the INCREASE study (2018) demonstrated beneficial effect of inhaled Treprostinil to treat PH in ILD. In view of this pioneering development, a paradigm shift in clinical approach to this disease phenotype is happening. There is a renewed vigor to develop a well validated screening tool for early detection and management. Currently inhaled Treprostinil is the only FDA approved therapy to treat this phenotype, but emergence of a therapy has opened a plethora of research toward new drug developments. Regardless of all these recent developments, the overall outlook still remains grim in this condition. This review article dwells on the current state of knowledge of pre-capillary PH due to ILD, especially its diagnosis and management, the recent progresses, and future evolutions in this field.

Functional Roles of CD26/DPP4 in Bleomycin-Induced Pulmonary Hypertension Associated with Interstitial Lung Disease

Pulmonary hypertension (PH) with interstitial lung diseases (ILDs) often causes intractable conditions. CD26/Dipeptidyl peptidase-4 (DPP4) is expressed in lung constituent cells and may be related to the pathogenesis of various respiratory diseases. We aimed to clarify the functional roles of CD26/DPP4 in PH-ILD, paying particular attention to vascular smooth muscle cells (SMCs). Dpp4 knockout (Dpp4KO) and wild type (WT) mice were administered bleomycin (BLM) intraperitoneally to establish a PH-ILD model. The BLM-induced increase in the right ventricular systolic pressure and the right ventricular hypertrophy observed in WT mice were attenuated in Dpp4KO mice. The BLM-induced vascular muscularization in small pulmonary vessels in Dpp4KO mice was milder than that in WT mice. The viability of TGFβ-stimulated human pulmonary artery SMCs (hPASMCs) was lowered due to the DPP4 knockdown with small interfering RNA. According to the results of the transcriptome analysis, upregulated genes in hPASMCs with TGFβ treatment were related to pulmonary vascular SMC proliferation via the Notch, PI3K-Akt, and NFκB signaling pathways. Additionally, DPP4 knockdown in hPASMCs inhibited the pathways upregulated by TGFβ treatment. These results suggest that genetic deficiency of Dpp4 protects against BLM-induced PH-ILD by alleviating vascular remodeling, potentially through the exertion of an antiproliferative effect via inhibition of the TGFβ-related pathways in PASMCs.

Pulmonary hypertension

Pulmonary hypertension encompasses a range of conditions directly or indirectly leading to elevated pressures within the pulmonary arteries. Five main groups of pulmonary hypertension are recognized, all defined by a mean pulmonary artery pressure of >20 mmHg: pulmonary arterial hypertension (rare), pulmonary hypertension associated with left-sided heart disease (very common), pulmonary hypertension associated with lung disease (common), pulmonary hypertension associated with pulmonary artery obstructions, usually related to thromboembolic disease (rare), and pulmonary hypertension with unclear and/or multifactorial mechanisms (rare). At least 1% of the world's population is affected, with a greater burden more likely in low-income and middle-income countries. Across all its forms, pulmonary hypertension is associated with adverse vascular remodelling with obstruction, stiffening and vasoconstriction of the pulmonary vasculature. Without proactive management this leads to hypertrophy and ultimately failure of the right ventricle, the main cause of death. In older individuals, dyspnoea is the most common symptom. Stepwise investigation precedes definitive diagnosis with right heart catheterization. Medical and surgical treatments are approved for pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension. There are emerging treatments for other forms of pulmonary hypertension; but current therapy primarily targets the underlying cause. There are still major gaps in basic, clinical and translational knowledge; thus, further research, with a focus on vulnerable populations, is needed to better characterize, detect and effectively treat all forms of pulmonary hypertension.

Overnight desaturation in interstitial lung diseases: links to pulmonary vasculopathy and mortality

Background

Overnight desaturation predicts poor prognosis across interstitial lung diseases (ILDs). The aim of the present study was to investigate whether nocturnal desaturation is associated with pulmonary vasculopathy and mortality.

Methods

A retrospective single centre study of 397 new ILD patients was carried out including patients with idiopathic pulmonary fibrosis (IPF) (n=107) and patients with non-IPF fibrotic ILD (n=290). This is the largest study to date of the effect of significant nocturnal desaturation (SND) (≥10% of total sleep time with oxygen saturation ≤90% measured by pulse oximetry).

Results

The prevalence of SND was 28/107 (26.2%) in IPF and 80/290 (27.6%) in non-IPF ILD. The prevalence of SND was higher in non-IPF ILDs than in IPF (p=0.025) in multivariate analysis. SND was associated with noninvasive markers of pulmonary hypertension (PH): tricuspid regurgitation velocity (TRV) (p<0.0001), brain natriuretic peptide (p<0.007), carbon monoxide transfer coefficient (p<0.0001), A-a gradient (p<0.0001), desaturation >4% in 6-min walking test (p<0.03) and pulmonary artery diameter (p<0.005). SND was independently associated with high echocardiographic PH probability in the entire cohort (OR 2.865, 95% CI 1.486-5.522, p<0.002) and in non-IPF fibrotic ILD (OR 3.492, 95% CI 1.597-7.636, p<0.002) in multivariate analysis. In multivariate analysis, SND was associated with mortality in the entire cohort (OR 1.734, 95% CI 1.202-2.499, p=0.003) and in IPF (OR 1.908, 95% CI 1.120-3.251, p=0.017) and non-IPF fibrotic ILD (OR 1.663, 95% CI 1.000-2.819, p=0.041). Separate models with exclusion of each one of the diagnostic subgroups showed that no subgroup was responsible for this finding in non-IPF ILDs. SND was a stronger marker of 5-year mortality than markers of PH.

Conclusion

SND was associated with high echocardiographic probability and mortality and was a stronger predictor of mortality in IPF and non-IPF ILDs grouped together to power the study.

Pulmonary hypertension in the setting of interstitial lung disease: Approach to management and treatment. A consensus statement from the Pulmonary Vascular Research Institute's Innovative Drug Development Initiative-Group 3 Pulmonary Hypertension

Pulmonary hypertension (PH) due to interstitial lung disease (ILD), a commonly encountered complication of fibrotic ILDs, is associated with significant morbidity and mortality. Until recently, the studies of pulmonary vasodilator therapy in PH-ILD have been largely disappointing, with some even demonstrating the potential for harm. This paper is part of a series of Consensus Statements from the Pulmonary Vascular Research Institute's Innovative Drug Development Initiative for Group 3 Pulmonary Hypertension, with prior publications covering pathogenesis, prevalence, clinical features, phenotyping, clinical trials, and impact of PH-ILD. It offers a comprehensive review of and a holistic approach to treatment of PH-ILD, including the management of underlying interstitial lung diseases, importance of treating the comorbidities, emphasis on importance of exercise and palliation of dyspnea, and review of the most up-to-date guidelines for referral for potential lung transplant work up. It also summarizes the prior, ongoing, and possibly future studies in treatment of the vascular derangement of this morbid condition.

Decoding signaling mechanisms: unraveling the targets of guanylate cyclase agonists in cardiovascular and digestive diseases

Soluble guanylate cyclase agonists and guanylate cyclase C agonists are two popular drugs for diseases of the cardiovascular system and digestive systems. The common denominator in these conditions is the potential therapeutic target of guanylate cyclase. Thanks to in-depth explorations of their underlying signaling mechanisms, the targets of these drugs are becoming clearer. This review explains the recent research progress regarding potential drugs in this class by introducing representative drugs and current findings on them.

Tyvaso DPI: Drug-device characteristics and patient clinical considerations

Tyvaso DPI is a drug-device combination therapy comprised of a small, portable, reusable, breath-powered, dry powder inhaler (DPI) for the delivery of treprostinil. It is approved for the treatment of pulmonary arterial hypertension and pulmonary hypertension associated with interstitial lung disease. Tyvaso DPI utilizes single-use prefilled cartridges to ensure proper dosing. Unlike nebulizer devices, administration of Tyvaso DPI is passive and does not require coordination with the device. The low-flow rate design results in targeted delivery to the peripheral lungs due to minimal drug loss from impaction in the oropharynx. The inert fumaryl diketopiperazine (FDKP) excipient forms microparticles that carry treprostinil into the airways, with a high fraction of the particles in the respirable range. In a clinical study in patients with pulmonary arterial hypertension, Tyvaso DPI had similar exposure and pharmacokinetics, low incidence of adverse events, and high patient satisfaction compared with nebulized treprostinil solution. Tyvaso DPI may be considered as a first prostacyclin agent or for those that do not tolerate other prostacyclin formulations, patients with pulmonary comorbidities, patients with mixed Group 1 and Group 3 pulmonary hypertension, or those that prefer an active lifestyle and need a portable, non-invasive treatment. Tyvaso DPI is a patient-preferred, maintenance-free, safe delivery option that may improve patient compliance and adherence.

Management of Pulmonary Hypertension Associated with Chronic Lung Disease

Pulmonary hypertension (PH) is a common complication of chronic lung diseases, particularly in chronic obstructive pulmonary disease (COPD) and interstitial lung diseases (ILD) and especially in advanced disease. It is associated with greater mortality and worse clinical course. Given the high prevalence of some respiratory disorders and because lung parenchymal abnormalities might be present in other PH groups, the appropriate diagnosis of PH associated with respiratory disease represents a clinical challenge. Patients with chronic lung disease presenting symptoms that exceed those expected by the pulmonary disease should be further evaluated by echocardiography. Confirmatory right heart catheterization is indicated in candidates to surgical treatments, suspected severe PH potentially amenable with targeted therapy, and, in general, in those conditions where the result of the hemodynamic assessment will determine treatment options. The treatment of choice for these patients who are hypoxemic is long-term oxygen therapy and pulmonary rehabilitation to improve symptoms. Lung transplant is the only curative therapy and can be considered in appropriate cases. Conventional vasodilators or drugs approved for pulmonary arterial hypertension (PAH) are not recommended in patients with mild-to-moderate PH because they may impair gas exchange and their lack of efficacy shown in randomized controlled trials. Patients with severe PH (as defined by pulmonary vascular resistance >5 Wood units) should be referred to a center with expertise in PH and lung diseases and ideally included in randomized controlled trials. Targeted PAH therapy might be considered in this subset of patients, with careful monitoring of gas exchange. In patients with ILD, inhaled treprostinil has been shown to improve functional ability and to delay clinical worsening.

What changed after the 2022 guidelines for pulmonary hypertension?

With an estimated prevalence of around 1%, pulmonary hypertension (PH) presents a relevant burden worldwide. In this review, we aim to give an overview of the novelties from the revised European Society of Cardiology (ESC) /European Respiratory Society (ERS) guidelines for the diagnosis and treatment of PH and their implication for the everyday clinical practice.

[Pathophysiology, diagnosis, prognosis and treatment of pulmonary hypertension associated with chronic lung disease]

The pathophysiology of pulmonary hypertension associated with chronic lung disease (PH-CLD) is complex, multifactorial, and not consistent among pulmonary diseases. However, pulmonary vasculopathy triggered by various factors, such as chronic alveolar hypoxia or cigarette smoking, seems to play a central role in the pathogenesis of PH-CLD. While the initial workup of PH-CLD is usually complicated by an overlap of symptoms of PH and the underlying lung disease, PH-CLD should be considered when there is a discrepancy between symptoms (especially exertional dyspnea) and pulmonary function tests. Clinical suspicion of PH-CLD can be strengthened by noninvasive diagnostic tools such as transthoracic echocardiography (TTE) or N-terminal pro-B-type natriuretic peptide (NT-pro-BNP). However, a right heart catheterization should only be performed in specialized centers to establish the diagnosis if therapeutic consequences for the patient were expected.The basic treatment of PH-CLD is optimal management of the underlying lung disease. Among the existing interventional and registry-based studies, only a small number of data suggests favorable outcomes when treating PH-CLD patients with PAH-specific medications. Some publications even suggest negative effects. Nevertheless, recent data on inhaled vasoactive therapy in PH-CLD showed positive results for inhaled Treprostinil, although long-term data for this therapeutic approach are still lacking. Treatment of PH-CLD patients with PAH-specific drugs should only be performed in specialized centers and preferably in the context of clinical trials.

[Pulmonary hypertension associated with lung disease]

Lung diseases and hypoventilation syndromes are often associated with pulmonary hypertension (PH). In most cases, PH is not severe. This is defined hemodynamically by a mean pulmonary arterial pressure (PAPm) > 20 mmHg, a pulmonary arterial wedge pressure (PAWP) ≤ 15 mmHg and a pulmonary vascular resistance of ≤ 5 Wood units (WU). Both the non-severe (PVR ≤ 5 WU) and much more the severe PH (PVR > 5 WU) have an unfavorable prognosis.If PH is suspected, it is recommended to primarily check whether risk factors for pulmonary arterial hypertension (PAH, group 1 PH) or chronic thromboembolic pulmonary hypertension (CTEPH, group 4 PH) are present. If risk factors are present or there is a suspicion of severe PH in lung patients, it is recommended that the patient should be presented to a PH outpatient clinic promptly.For patients with severe PH associated with lung diseases, personalized, individual therapy is recommended - if possible within the framework of therapy studies. Currently, a therapy attempt with PH specific drugs should only be considered in COPD patients if the associated PH is severe and a "pulmonary vascular" phenotype (severe precapillary PH, but typically only mild to moderate airway obstruction, no or mild hypercapnia and DLCO < 45 % of predicted value) is present. In patients with severe PH associated with interstitial lung disease phosphodiesterase-5-inhibitors may be considered in individual cases. Inhaled treprostinil may be considered also in non-severe PH in this patient population.

Riociguat in patients with early diffuse cutaneous systemic sclerosis (RISE-SSc): open-label, long-term extension of a phase 2b, randomised, placebo-controlled trial

BACKGROUND

The phase 2b Riociguat Safety and Efficacy in Patients with Diffuse Cutaneous Systemic Sclerosis (RISE-SSc) trial investigated riociguat versus placebo in early diffuse cutaneous systemic sclerosis. The long-term extension evaluated safety and exploratory treatment effects for an additional year.

METHODS

Patients were enrolled to RISE-SSc between Jan 15, 2015, and Dec 8, 2016. Those who completed the 52-week, randomised, parallel-group, placebo-controlled, double-blind phase were eligible for the long-term extension. Patients originally assigned to riociguat continued therapy (riociguat-riociguat group). Those originally assigned to placebo were switched to riociguat (placebo-riociguat group), adjusted up to 2·5 mg three times daily in a 10-week, double-blind dose-adjustment phase, followed by an open-label phase. Statistical analyses were descriptive. Safety including adverse events and serious adverse events was assessed in the long-term safety analysis set (all patients randomly assigned and treated with study medication in the double-blind phase who continued study medication in the long-term extension). The RISE-SSc trial is registered with ClinicalTrials.gov, NCT02283762.

FINDINGS

In total, 87 (72%) of 121 patients in the main RISE-SSc study entered the long-term extension (riociguat-riociguat, n=42; placebo-riociguat, n=45). 65 (75%) of 87 patients were women, 22 (25%) were men, and 62 (71%) were White. Overall, 82 (94%) of 87 patients in the long-term extension had an adverse event; most (66 [76%] of 87) were of mild to moderate severity, with no increase in pulmonary-related serious adverse events in patients with interstitial lung disease.

INTERPRETATION

No new safety signals were observed with long-term riociguat in patients with early diffuse cutaneous systemic sclerosis. Study limitations include the absence of a comparator group in this open-label extension study.

FUNDING

Bayer and Merck Sharp & Dohme.

Connective tissue disease-associated pulmonary hypertension: A comprehensive review

Connective tissue diseases (CTDs) can be associated with various forms of pulmonary hypertension, including pulmonary arterial hypertension (PAH), pulmonary veno-occlusive disease, pulmonary venous hypertension, interstitial lung disease-associated pulmonary hypertension, chronic thromboembolic pulmonary hypertension, and sometimes a combination of several processes. The prevalence of PAH varies among the different CTDs, with systemic sclerosis (SSc) having the highest at 8%-12%. The most recent European Society of Cardiology/European Respiratory Society guidelines recommend routine annual screening for PAH in SSc and CTDs with SSc features. As CTDs can be associated with a myriad of presentations of pulmonary hypertension, a thorough evaluation to include a right heart catheterization to clearly delineate the hemodynamic profile is essential in developing an appropriate treatment plan. Treatment strategies will depend on the predominant phenotype of pulmonary vasculopathy. In general, management approach to CTD-PAH mirrors that of idiopathic PAH. Despite this, outcomes of CTD-PAH are inferior to those of idiopathic PAH, with those of SSc-PAH being particularly poor. Reasons for this may include extrapulmonary manifestations of CTDs, including renal disease and gastrointestinal involvement, concurrent interstitial lung disease, and differences in the innate response of the right ventricle to increased pulmonary vascular resistance. Early referral for lung transplant evaluation of patients with CTD-PAH, particularly SSc-PAH, is recommended. It is hoped that in the near future, additional therapies may be added to the armamentarium of effective treatments for CTD-PAH. Ultimately, a better understanding of the pathogenesis of CTD-PAH will be required to develop targeted therapies for this morbid condition.

Pulmonary Hypertension in Interstitial Lung Disease: Updates in Disease, Diagnosis, and Therapeutics

Pulmonary hypertension is a debilitating condition that frequently develops in the setting of interstitial lung disease, likely related to chronic alveolar hypoxemia and pulmonary vascular remodeling. This disease process is likely to be identified more frequently by providers given recent advancements in definitions and diagnostic modalities, and provides practitioners with emerging opportunities to improve patient outcomes and quality of life. Despite years of data suggesting against the efficacy of pulmonary vasodilator therapy in patients with pulmonary hypertension due to interstitial lung disease, new data have emerged identifying promising advancements in therapeutics. The authors present to you a comprehensive review of pulmonary hypertension in interstitial lung disease, reviewing our current understanding of pathophysiology, updates in diagnostic approaches, and highlights of recent clinical trials which provide an effective approach for medical management.