ET-1 stimulates pulmonary arterial smooth muscle cell proliferation via induction of reactive oxygen species

Selexipag for the treatment of pulmonary arterial hypertension

INTRODUCTION

: Pulmonary arterial hypertension (PAH) is a rare pulmonary vasculopathy. This review focuses on selexipag, a prostacyclin receptor agonist validated for the treatment of PAH.

AREAS COVERED

We review the structure, mechanisms of action, pharmacokinetics, and pharmacodynamics of selexipag. Clinical efficacy and tolerability are discussed using the main clinical trial published for selexipag (GRIPHON) and its post-hoc analysis.

EXPERT OPINION

Selexipag should be added as a triple oral combination therapy in case of insufficient response to oral combination therapy with endothelin receptor antagonist and phosphodiesterase 5 inhibitor. However, selexipag should not replace parenteral prostacyclin in high-risk patients.

Targeted Drugs for Treatment of Pulmonary Arterial Hypertension: Past, Present, and Future Perspectives

Pulmonary arterial hypertension (PAH) is a devastating disease that can lead to right ventricular failure and premature death. Although approved drugs have been shown to be safe and effective, PAH remains a severe clinical condition, and the long-term survival of patients with PAH is still suboptimal. Thus, potential therapeutic targets and new agents to treat PAH are urgently needed. In recent years, a variety of related pathways and potential therapeutic targets have been found, which brings new hope for PAH therapy. In this perspective, not only are the marketed drugs used to treat PAH summarized but also the recently developed novel pharmaceutical therapies currently in clinical trials are discussed. Furthermore, the advances in natural products as potential treatment for PAH are also updated.

Assessment of the REPLACE study composite endpoint in riociguat-treated patients in the PATENT study

The goal of treatment in patients with pulmonary arterial hypertension is to achieve a low risk status, indicating a favorable long-term outcome. The REPLACE study investigated the efficacy of switching to riociguat in patients with pulmonary arterial hypertension and an insufficient response to phosphodiesterase-5 inhibitors. In this post hoc analysis, we applied the REPLACE composite endpoint of clinical improvement to the placebo-controlled PATENT-1 study of riociguat in pulmonary arterial hypertension and its long-term extension, PATENT-2. Clinical improvement was defined as ≥2 of the following in patients who completed the study without clinical worsening: ≥10% or ≥30 m improvement in 6-minute walking distance; World Health Organization functional class I or II; ≥30% decrease in N-terminal prohormone of brain natriuretic peptide. At PATENT-1 Week 12, patients treated with riociguat were more likely to achieve the composite endpoint vs. placebo (P < 0.0001), with similar results in pretreated (P = 0.0189) and treatment-naïve (P < 0.0001) patients. Achievement of the composite endpoint at Week 12 was associated with a 45% reduction in relative risk of death and a 19% reduction in relative risk of clinical worsening in PATENT-2. Overall, these data suggest that use of the REPLACE composite endpoint in patients with pulmonary arterial hypertension is a valid assessment of response to treatment.

Epigenetic Regulation of Pulmonary Arterial Hypertension-Induced Vascular and Right Ventricular Remodeling: New Opportunities?

Pulmonary artery hypertension (PAH) is a rare chronic disease with high impact on patients’ quality of life and currently no available cure. PAH is characterized by constant remodeling of the pulmonary artery by increased proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs), fibroblasts (FBs) and endothelial cells (ECs). This remodeling eventually leads to increased pressure in the right ventricle (RV) and subsequent right ventricle hypertrophy (RVH) which, when left untreated, progresses into right ventricle failure (RVF). PAH can not only originate from heritable mutations, but also develop as a consequence of congenital heart disease, exposure to drugs or toxins, HIV, connective tissue disease or be idiopathic. While much attention was drawn into investigating and developing therapies related to the most well understood signaling pathways in PAH, in the last decade, a shift towards understanding the epigenetic mechanisms driving the disease occurred. In this review, we reflect on the different epigenetic regulatory factors that are associated with the pathology of RV remodeling, and on their relevance towards a better understanding of the disease and subsequently, the development of new and more efficient therapeutic strategies.

Novel composite clinical endpoints and risk scores used in clinical trials in pulmonary arterial hypertension

This manuscript on endpoints incorporates the broad experience of members of Pulmonary Vascular Research Institute’s Innovative Drug Development Initiative as an open debate platform for academia, the pharmaceutical industry and regulatory experts surrounding the future design of clinical trials in pulmonary hypertension. It reviews our current understanding of endpoints used in phase 2 and 3 trials for pulmonary hypertension and discusses in detail the value of newer approaches. These include the roles of composite endpoints and how these can be developed and validated. The newer concept of risk analysis is also discussed, including how such risk scores might be utilised as endpoints in clinical trials.

Management of Pulmonary Arterial Hypertension

Purpose of Review

This review focuses on the therapeutic management and individualized approach to Group 1 pulmonary arterial hypertension (PAH), utilizing Food and Drug Administration-approved PAH-specific therapies and various interventional and surgical options for PAH.

Recent Findings

The paradigm for the optimal management of PAH has shifted in recent years. Upfront combination therapy with an endothelin receptor antagonist and a phosphodiesterase 5 inhibitor is now widely accepted as standard of care. In addition, there is increasing emphasis on starting prostanoids early in order to delay time to clinical worsening. However, less is known regarding which prostanoid agent to initiate and the optimum time to do so. In order to facilitate shared decision-making, there is an increasing need for decision tools based on guidelines and collective clinical experiences to navigate between pharmacologic and interventional treatments, as well as explore innovative, therapeutic pathways for PAH.

Summary

The management of PAH has become increasingly complex. With a growing number of PAH-specific therapies, intimate knowledge of the therapeutics and the potential barriers to adherence are integral to providing optimal care for this high-risk patient population. While current PAH-specific therapies largely mediate their effects through pulmonary vasodilation, ongoing research efforts are focused on ways to disrupt the mechanisms leading to pulmonary vascular remodeling. By targeting aberrations identified in the metabolism and proliferative state of pulmonary vascular cells, novel PAH treatment pathways may be just on the horizon.

Clinical trial design in phase 2 and 3 trials for pulmonary hypertension

This article on clinical trial design incorporates the broad experience of members of the Pulmonary Vascular Research Institute's (PVRI) Innovative Drug Development Initiative (IDDI) as an open debate platform for academia, the pharmaceutical industry and regulatory experts surrounding the future design of clinical trials in pulmonary hypertension. It is increasingly clear that the design of phase 2 and 3 trials in pulmonary hypertension will have to diversify from the traditional randomised double-blind design, given the anticipated need to trial novel therapeutic approaches in the immediate future. This article reviews a wide range of differing approaches and places these into context within the field of pulmonary hypertension.

Repurposing of medications for pulmonary arterial hypertension

This manuscript on drug repurposing incorporates the broad experience of members of the Pulmonary Vascular Research Institute's Innovative Drug Development Initiative as an open debate platform for academia, the pharmaceutical industry and regulatory experts surrounding the future design of clinical trials in pulmonary hypertension. Drug repurposing, use of a drug in a disease for which it was not originally developed, in pulmonary arterial hypertension has been a remarkable success story, as highlighted by positive large phase 3 clinical trials using epoprostenol, bosentan, iloprost, and sildenafil. Despite the availability of multiple therapies for pulmonary arterial hypertension, mortality rates have modestly changed. Moreover, pulmonary arterial hypertension patients are highly symptomatic and frequently end up on parental therapy and lung transplant waiting lists. Therefore, an unmet need for new treatments exists and drug repurposing may be an important avenue to address this problem.

Pediatric Pulmonary Arterial Hypertension

Pulmonary hypertension (PH), the syndrome of increased pressure in the pulmonary arteries, is associated with significant morbidity and mortality for affected children and is associated with a variety of potential underlying causes. Several pulmonary arterial hypertension-targeted therapies have become available to reduce pulmonary artery pressure and improve outcome, but there is still no cure for most patients. This review provides a description of select causes of PH encountered in pediatrics and an update on the most recent data pertaining to evaluation and management of children with PH. Available evidence for specific classes of PH-targeted therapies in pediatrics is discussed.

Effect of ambrisentan on echocardiographic and Doppler measures from patients in China with pulmonary arterial hypertension

BACKGROUND

We retrospectively evaluated the echocardiographic data of ambrisentan-treated patients with pulmonary arterial hypertension (PAH) (NCT01808313).

METHODS

Change from baseline in right ventricle (RV) systolic function, right heart structure, and pulmonary artery systolic pressure (PASP) prognosis to Weeks 12 and 24 was evaluated by echocardiography.

RESULTS

In the overall population, the mean tissue Doppler-derived tricuspid lateral annular systolic velocity (S') increased by 0.6 cm/s at both Weeks 12 (p < 0.001) and 24 (p = 0.004) and tricuspid annular plane systolic excursion increased by 0.13 cm at Week 12 and 0.15 cm at Week 24 (both p < 0.001). A marked decrease in transverse and longitudinal RV and RA diameter at Weeks 12 and 24 was observed. A significant decrease in diastolic eccentricity index at both Weeks 12 (-0.1; p = 0.02) and 24 (-0.1; p = 0.001). The decrease in PASP from baseline was significant at both Weeks 12 (-9.5 mmHg; p<0.001) and 24 (-7.6 mmHg; p<0.001), while a decrease in the estimated right atrium pressure was found to be significant at Week 24 (-0.8mmHg; p = 0.01).

CONCLUSION

Significant improvements in a number of RV echocardiographic parameters were observed at Weeks 12 and 24 after ambrisentan treatment in patients with PAH.

Ambrisentan, an endothelin receptor type A-selective antagonist, inhibits cancer cell migration, invasion, and metastasis

Several studies reported a central role of the endothelin type A receptor (ETAR) in tumor progression leading to the formation of metastasis. Here, we investigated the in vitro and in vivo anti-tumor effects of the FDA-approved ETAR antagonist, Ambrisentan, which is currently used to treat patients with pulmonary arterial hypertension. In vitro, Ambrisentan inhibited both spontaneous and induced migration/invasion capacity of different tumor cells (COLO-357 metastatic pancreatic adenocarcinoma, OvCar3 ovarian carcinoma, MDA-MB-231 breast adenocarcinoma, and HL-60 promyelocytic leukemia). Whole transcriptome analysis using RNAseq indicated Ambrisentan's inhibitory effects on the whole transcriptome of resting and PAR2-activated COLO-357 cells, which tended to normalize to an unstimulated profile. Finally, in a pre-clinical murine model of metastatic breast cancer, treatment with Ambrisentan was effective in decreasing metastasis into the lungs and liver. Importantly, this was associated with a significant enhancement in animal survival. Taken together, our work suggests a new therapeutic application for Ambrisentan in the treatment of cancer metastasis.

Distribution and relative expression of vasoactive receptors on arteries

Arterial tone is regulated by multiple ligand-receptor interactions, and its dysregulation is involved in ischemic conditions such as acute coronary spasm or syndrome. Understanding the distribution of vasoactive receptors on different arteries may help guide the development of tissue-specific vasoactive treatments against arterial dysfunction. Tissues were harvested from coronary, mesenteric, pulmonary, renal and peripheral human artery (n = 6 samples of each) and examined using a human antibody array to determine the expression of 29 vasoactive receptors and 3 endothelin ligands. Across all types of arteries, outer diameter ranged from 2.24 ± 0.63 to 3.65 ± 0.40 mm, and AVPR1A was the most abundant receptor. The expression level of AVPR1A in pulmonary artery was similar to that in renal artery, 2.2 times that in mesenteric artery, 1.9 times that in peripheral artery, and 2.2 times that in coronary artery. Endothelin-1 was expressed at significantly higher levels in pulmonary artery than peripheral artery (8.8 times), mesenteric artery (5.3 times), renal artery (7.9 times), and coronary artery (2.4 times). Expression of ADRA2B was significantly higher in coronary artery than peripheral artery. Immunohistochemistry revealed abundant ADRA2B in coronary artery, especially vessels with diameters below 50 μm, but not in myocardium. ADRA2C, in contrast, was expressed in both myocardium and blood vessels. The high expression of ADRA2B in coronary artery but not myocardium highlights the need to further characterize its function. Our results help establish the distribution and relative levels of tone-related receptors in different types of arteries, which may guide artery-specific treatments.

Pharmacologic therapy for pulmonary artery hypertension

PURPOSE OF REVIEW

Pulmonary arterial hypertension (PAH) is a disease that carries a significant mortality left untreated. This article aims to review pharmacotherapeutics for PAH.

RECENT FINDINGS

PAH-specific therapies have evolved over the last three decades and have expanded from one therapy in the 1990s to 14 FDA-approved medications. Current therapies are directed at restoring the imbalance of vasoactive mediators that include nitric oxide, endothelin and prostacyclin. Although these agents are effective as monotherapy, recent trials have promulgated the strategy of upfront combination therapy. The availability of oral prostacyclin agonists has also allowed for expanded treatment options. Risk assessment is vital in guiding therapy for PAH patients. There is ongoing focus on targeting pathological mechanisms of the disease via novel therapies and repurposing existing drugs.

SUMMARY

There is an array of medications available for the treatment of PAH. Prudent combination of therapies to maximize treatment effect can improve morbidity and mortality. This article reviews the data supporting these therapies and attempts to outline an approach to patient management.

Long-term survival outcome for pre-capillary pulmonary hypertension at a Japanese single center

In recent years, several treatment options for patients with pre-capillary pulmonary hypertension (PH) have improved the short-term prognosis. However, the long-term survival for pre-capillary PH has not been well investigated. This study sought to investigate the long-term survival for pre-capillary PH in Kurume University Hospital. A total of 144 patients with pre-capillary PH (110 women, mean age 55.1 ± 17.9 years) were enrolled. The maximal duration of followup was 15 years with a mean followup of 5.77 years. The 15 year survival was 59.1% for pre-capillary PH, 68.5% for pulmonary arterial hypertension (PAH), and 44.3% for chronic thromboembolic PH. The 5 year survival was 50.9% for PH due to lung disease (PH-LD), indicating the worst in the pre-capillary PH subgroups. The survival for portopulmonary hypertension was the lowest among PAH groups, and PAH associated with connective tissue disease and congenital heart disease decreased 10 years after diagnosis. A 6 min walk distance and elevated brain natriuretic peptide were significantly associated with survival outcome in pre-capillary PH patients and diastolic pulmonary arterial pressure was related to survival for PH-LD. The survivals were different among pre-capillary PH groups in our hospital. Above all, the long-term survival was better than in previous reports.

The Clinical Efficacy of Endothelin Receptor Antagonists in Patients with Pulmonary Arterial Hypertension

Therapeutic strategies for pulmonary arterial hypertension (PAH) have made remarkable progress over the last two decades. Currently, 3 types of drugs can be used to treat PAH; prostacyclins, phosphodiesterase 5 inhibitors, and endothelin receptor antagonists (ERA). In Japan, the first generation ERA bosentan was reimbursed in 2005, following which the 2nd generation ERAs ambrisentan and macitentan were reimbursed in 2009 and 2015, respectively. The efficacy of each ERA on hemodynamics in PAH patients remains to be elucidated. The aims of this study were to evaluate the hemodynamic effects of ERAs and compare these effects among each generation of ERAs.We retrospectively examined the clinical parameters of 42 PAH patients who were prescribed an ERA (15 bosentan, 12 ambrisentan, and 15 macitentan) and who underwent a hemodynamic examination before and after ERA introduction at our institution from January 2007 to July 2019.In a total of 42 patients, mean pulmonary arterial pressure (mPAP) and pulmonary vascular resistance (PVR) were significantly decreased and cardiac index was significantly increased after ERA introduction (P < 0.001) and the World Health Organization-Functional class (WHO-Fc) was significantly improved after ERA introduction (P = 0.005). Next, in a comparison between 1st and 2nd generation ERAs, 2nd generation ERAs were found to have brought about greater improvements in hemodynamic parameters (mPAP and PVR. P < 0.01), heart rate, brain natriuretic peptide, arterial oxygen saturation, and mixed venous oxygen saturation than the 1st generation ERA bosentan.We conclude that all ERAs could successfully improve the hemodynamics of PAH patients and that the newer generation ERAs, ambrisentan and macitentan, seemed to be preferable to bosentan.

Angiotensin converting enzyme 2 and angiotensin (1-7) axis in pulmonary arterial hypertension

BACKGROUND

In animal models of pulmonary arterial hypertension (PAH), angiotensin-converting enzyme (ACE)2 and angiotensin (Ang)-(1-7) have been shown to have vasodilatory, antiproliferative, antifibrotic and antihypertrophic properties. However, the status and role of the ACE2-Ang(1-7) axis in human PAH is incompletely understood.

METHODS

We studied 85 patients with a diagnosis of PAH of distinct aetiologies. 55 healthy blood donors paired for age and sex served as controls. Blood samples were obtained from the pulmonary artery in patients with PAH during right heart catheterisation. Peripheral blood was obtained for both groups. Ang(1-7) and -II were measured using zone capillary electrophoresis. Aldosterone, Ang(1-9), AngA and ACE2 were measured using ELISA, and ACE2 activity was determined enzymatically.

RESULTS

Of the 85 patients, 47 had idiopathic PAH, 25 had PAH associated with congenital heart disease and 13 had PAH associated with collagen vascular disease. Compared to controls, patients with PAH had a higher concentration of AngII (median 1.03, interquartile range 0.72-1.88 pmol·mL^-1 versus 0.19, 0.10-0.37 pmol·mL^-1; p<0.001) and of aldosterone (88.7, 58.7-132 ng·dL^-1 versus 12.9, 9.55-19.9 ng·dL^-1; p<0.001). Conversely, PAH patients had a lower concentration of Ang(1-7) than controls (0.69, 0.474-0.91 pmol·mL^-1 versus 4.07, 2.82-6.73 pmol·mL^-1; p<0.001), and a lower concentration of Ang(1-9) and AngA. Similarly, the ACE2 concentration was higher than in controls (8.7, 5.35-13.2 ng·mL^-1 versus 4.53, 1.47-14.3 ng·mL^-1; p=0.011), whereas the ACE2 activity was significantly reduced (1.88, 1.08-2.81 nmol·mL^-1 versus 5.97, 3.1-17.8 nmol·mL^-1; p<0.001). No significant differences were found among the three different aetiological forms of PAH.

CONCLUSIONS

The AngII-ACE2-Ang(1-7) axis appears to be altered in human PAH and we propose that this imbalance, in favour of AngII, plays a role in the pathogenesis of the severe PAH. Further mechanistic studies are warranted.

Efficacy and safety of ambrisentan in Chinese patients with connective tissue disease-pulmonary arterial hypertension: a post-hoc analysis

BACKGROUND

The efficacy and safety of ambrisentan has been previously evaluated in Chinese patients with pulmonary arterial hypertension (PAH). This post-hoc analysis assessed the efficacy and safety of ambrisentan in a subgroup of connective tissue disease (CTD) patients with PAH.

METHODS

In this open-label, single-arm study, patients received ambrisentan 5 mg once daily for 12 weeks, followed by 12-week dose titration period (dose up to 10 mg). Efficacy endpoints included change from baseline in exercise capacity (measured by 6-min walk test [6MWT]), N-terminal pro B type natriuretic peptide (NT-proBNP) plasma levels, WHO Functional Class (FC) and Borg Dyspnoea Index (BDI) scores from baseline to weeks 12 and 24. Safety endpoints included time to clinical worsening and incidence of adverse events (AEs).

RESULTS

In total, 71 Chinese patients with CTD-PAH were included in this analysis. Ambrisentan treatment significantly improved exercise capacity (6MWT) from baseline (mean: 366.4 m) to week 12 (63.8 m, p < 0.001) and week 24 (73.2 m, p < 0.001). A significant reduction in NT-proBNP levels was observed from baseline (mean: 1837.5 ng/L) to week 12 (- 1156.8 ng/L, p < 0.001) and week 24 (- 1095.5 ng/L, p < 0.001). BDI scores decreased significantly at week 12 (- 0.6, p < 0.001) and week 24 (- 0.4, p = 0.002) from baseline (mean: 2.7). The WHO FC improved in 29 (40.8%) and 34 (47.9%) patients at weeks 12 and 24, respectively. Adverse events were reported in 52 (73.2%) patients. One patient (1.4%) experienced clinical worsening at week 24.

CONCLUSION

Ambrisentan showed significant improvement in exercise capacity and no clinical worsening in the majority of Chinese patients with CTD-PAH in the 24-week treatment period. The AEs observed in the CTD-PAH subgroup were consistent with the known safety profile of ambrisentan in the overall Chinese PAH population.

TRIAL REGISTRATION

ClinicalTrial.gov Identifier, https://clinicaltrials.gov/, NCT01808313 Registration date (first time): February 28, 2013.

Guidelines for the Treatment of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a rare form of pulmonary hypertension characterized by a progressive obliterative vasculopathy of the distal pulmonary arterial circulation that usually leads to right ventricular failure and death. Over the last 25 years, more than a dozen drugs representing five drug classes have been developed and approved for the treatment of this devastating disease. Due to the small number of patients afflicted by PAH, most health care providers have little experience with its management. To address this gap in medical knowledge, treatment guidelines have been developed by professional organizations and expert committees. Over the last few years, these guidelines have been updated to address findings from recent clinical trials and ongoing experience with these drugs. This review provides an update on the most recently published treatment guidelines for pharmacologic treatment of PAH and incorporates them into a contemporary approach to the treatment of this disease.

Treatment of newly diagnosed sarcoid-associated pulmonary hypertension with ambrisentan and tadalafil combination therapy

Sarcoid Associated Pulmonary Hypertension (SAPH) is a common complication of sarcoidosis and is associated with poor prognosis. SAPH can be due to multiple synergistic mechanisms and current therapeutic strategies treat systemic sarcoidosis and pulmonary hypertension separately. Several studies have been performed to develop an effective therapy for SAPH but have been met with mixed results. The AMBITION trial successfully treated incident patients with pulmonary arterial hypertension (PAH) with the upfront combination of ambrisentan and tadalafil; however combination therapy has not yet been studied in patients with SAPH. Here we report a cohort of patients with newly diagnosed SAPH who were treated with upfront combination therapy per the AMBITION study protocol. We report three subjects with newly diagnosed SAPH who were treated with combination ambrisentan and tadalafil. Baseline hemodynamics were compared with those from surveillance right heart catheterization while on therapy. Mean follow up period was 17 months. Each subject demonstrated clinical and hemodynamic improvement with combination therapy. This series is the first to evaluate upfront combination ambrisentan and tadalafil therapy for treatment of newly diagnosed SAPH. Despite the impressive clinical and hemodynamic improvement, the study is limited by its small size and retrospective nature. While these initial results are promising, further work is needed to fully evaluate this regimen for treatment of SAPH. (Sarcoidosis Vasc Diffuse Lung Dis 2020; 37 (2): 234-238).

Current and emerging therapeutic approaches to pulmonary hypertension

Pulmonary arterial hypertension (PAH) is a progressive and fatal lung disease of multifactorial etiology. Most of the available drugs and FDA-approved therapies for treating pulmonary hypertension attempt to overcome the imbalance between vasoactive and vasodilator mediators, and restore the endothelial cell function. Traditional medications for treating PAH include the prostacyclin analogs and receptor agonists, phosphodiesterase 5 inhibitors, endothelin-receptor antagonists, and cGMP activators. While the current FDA-approved drugs showed improvements in quality of life and hemodynamic parameters, they have shown only very limited beneficial effects on survival and disease progression. None of them offers a cure against PAH, and the median survival rate remains less than three years from diagnosis. Extensive research efforts have led to the emergence of innovative therapeutic approaches in the area of PAH. In this review, we provide an overview of the current FDA-approved therapies in PAH and discuss the associated clinical trials and reported-side effects. As recent studies have led to the emergence of innovative therapeutic approaches in the area of PAH, we also focus on the latest promising therapies in preclinical studies such as stem cell-based therapies, gene transfer, and epigenetic therapies.

Pulmonary Hypertension Phenotypes in Systemic Sclerosis: The Right Diagnosis for the Right Treatment

Systemic sclerosis is an auto-immune disease characterized by skin involvement that often affects multiple organ systems. Pulmonary hypertension is a common finding that can significantly impact prognosis. Molecular pathophysiological mechanisms underlying pulmonary hypertension in systemic sclerosis can be extremely heterogeneous, leading to distinct clinical phenotypes. In addition, different causes of pulmonary hypertension may overlap within the same patient. Since pulmonary hypertension treatment is very different for each phenotype, it is fundamental to perform an adequate diagnostic work-up to properly and promptly identify the prevalent mechanism underlying pulmonary hypertension in order to start the right therapies. When pulmonary hypertension is caused by a primary vasculopathy of the small pulmonary arteries, treatment with pulmonary vasodilators, often in an initial double-combination regimen, is indicated, aimed at reducing the mortality risk profile. In this review, we describe the different clinical phenotypes of pulmonary hypertension in the scleroderma population and discuss the utility of clinical tools to identify the presence of pulmonary vascular disease. Furthermore, we focus on systemic sclerosis-associated pulmonary arterial hypertension, highlighting the advances in the knowledge of right ventricular dysfunction in this setting and the latest updates in terms of treatment with pulmonary vasodilator drugs.

Heart‑lung crosstalk in pulmonary arterial hypertension following myocardial infarction (Review)

Left heart disease is the main cause of clinical pulmonary arterial hypertension (PAH). Common types of left heart disease that result in PAH include heart failure, left ventricular systolic dysfunction, left ventricular diastolic dysfunction and valvular disease. It is currently believed that mechanical pressure caused by high pulmonary venous pressure is the main cause of myocardial infarction (MI) in individuals with ischemic cardiomyopathy and left ventricular systolic dysfunction. In the presence of decreased cardiac function, vascular remodeling of pulmonary vessels in response to long-term stimulation by high pressure in turn leads to exacerbation of PAH. However, the underlying pathological mechanisms remain unclear. Elucidating the association between the development of MI and PAH may lead to a better understanding of potential risk factors and better disease treatment. In this article, the pathophysiological effects of multiple systems in individuals with MI and PAH were reviewed in order to provide a general perspective on various potential interactions between cardiomyocytes and pulmonary vascular cells.

Patient-reported outcome instruments in clinical trials of systemic sclerosis

Patient-reported outcome instruments provide valuable insight into disease-related morbidity known only to the patient and complement more objective outcome tools in the clinical trial setting. They are of particular importance in systemic sclerosis owing to the challenges around defining disease activity, the episodic nature of many disease-specific manifestations and the paucity of validated objective surrogate outcome measures for use in clinical trials. Early clinical trials of systemic sclerosis often incorporated legacy patient-reported outcome instruments, but the last 20 years has witnessed the emergence of several scleroderma-specific instruments that are now being routinely used alongside other outcomes in systemic sclerosis clinical trials. More recently, the value of patient-reported outcomes has been highlighted by their prominence in the American College of Rheumatology Combined Response Index for Systemic Sclerosis that has been utilized as the primary endpoint of recent clinical trials of early diffuse systemic sclerosis. This review considers the role and performance of the various patient-reported outcome instruments utilized in systemic sclerosis clinical trials, the current positioning of patient-reported outcome instruments within clinical trial endpoint models across the range of systemic sclerosis disease manifestations and, where applicable, we shall highlight areas for future research.

Pulmonary arterial hypertension specific therapy: The old and the new

Pulmonary arterial hypertension (PAH) is a vascular disorder associated with high morbidity and mortality rate and is characterized by pulmonary vascular remodeling and increased pulmonary vascular resistance, ultimately resulting in right ventricular failure and death. Over the past few decades, significant advances in the understanding of the epidemiology, pathogenesis, and pathophysiology of pulmonary arterial hypertension have occured. This has led to the development of disease specific treatment including prostanoids, endothelin receptor antagonists, phosphodiesterase inhibitors, and soluble guanylate cyclase stimulators. These therapies significantly improve exercise capacity, quality of life, pulmonary hemodynamics, but none of the current treatments are actually curative and long-term prognosis remains poor. Thus, there is a clear need to develop new therapies. Several potential pharmacologic agents for the treatment of pulmonary arterial hypertension are under clinical development and some promising results with these treatments have been reported. These agents include tyrosine protein kinase inhibitors, rho-kinase inhibitors, synthetically produced vasoactive intestinal peptide, antagonists of the 5-HT2 receptors, and others. This article will review several of these promising new therapies and will discuss the current evidence regarding their potential benefit in pulmonary arterial hypertension.

Advances in targeted therapy for chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by unresolved thrombi in the pulmonary arteries and microvasculopathy in nonoccluded areas. If left untreated, progressive pulmonary hypertension will induce right heart failure and, finally, death. Currently, pulmonary endarterectomy (PEA) remains the only method that has the potential to cure CTEPH. Unfortunately, up to 40% of patients are ineligible for this procedure for various reasons. In recent years, refined balloon pulmonary angioplasty (BPA) has become an alternative option for inoperable CTEPH patients, and it may be another curative treatment in the future, particularly in combination with prior PEA. Nevertheless, 23% of patients still suffer from persistent PH after BPA. Given that CTEPH shares many similarities with idiopathic pulmonary arterial hypertension (PAH), targeted drugs developed for PAH are also attractive options for CTEPH, especially for inoperable or persistent/recurrent CTEPH patients. To date, riociguat, macitentan, and subcutaneous treprostinil are the only drugs proven by randomized control trials to be capable of improving the exercise capacity (6-min walking distance) of CTEPH patients. In this review, we summarize the achievements and unresolved problems of PAH-targeted therapy for CTEPH over the last decade.

Pulmonary arterial hypertension: Rationale for using multiple vs. single drug therapy

Pulmonary arterial hypertension (PAH) is defined by a heterogenous pathobiology that corresponds to variable clinical presentation, treatment response, and prognosis across affected patients. The approach to pharmacotherapeutics in PAH has evolved since the introduction of the first prostacyclin replacement drug, which was trialed in patients with end-stage disease as a strategy by which to delay or prevent mortality. Subsequently, the aim of care in PAH has shifted toward minimizing symptoms, improving functional capacity, delaying disease progression, and prolonging life. Thus, treatments are now implemented earlier and according to the evidence base, which spans more than twenty years and includes patients at various stages of disease. Overall, the evidence supports multidrug therapy rather than monotherapy in the majority of PAH patients. Among incident patients, up-front combination therapy with ambrisentan and tadalafil or other comparable agents within these drug classes is recommended based on strong clinical trial data. In the near future, up-front triple therapy may be emerge as bona fide treatment approach in selected patients. Future goals that are already under consideration in PAH include stronger integration of pathobiological characteristics when considering the use of specific drugs, or the development of novel therapies, toward precision medicine-based clinical pharmacology.

Reduced RVSWI Is Associated With Increased Mortality in Connective Tissue Disease Associated Pulmonary Arterial Hypertension

Rationale: The prognosis of pulmonary arterial hypertension is poor, especially amongst patients with connective tissue disease related pulmonary arterial hypertension. Right ventricular contractility is known to be decreased in scleroderma related pulmonary arterial hypertension. However, it is not known whether intrinsic right ventricular dysfunction is seen in a general CTD population. Objectives: In this study of a large cohort of patients with pulmonary arterial hypertension with multi-year follow-up, we sought to examine the association of measurements of right ventricular function with survival in connective tissue disease associated pulmonary arterial hypertension. Methods: Clinical characteristics of a deidentified cohort of 845 patients with pulmonary arterial hypertension were compared between patients with and without connective tissue disease. The Kaplan-Meier method was used to examine the survival of patients over more than 4 years. The association between right ventricular stroke work index and mortality was examined in patients with connective tissue disease associated pulmonary arterial hypertension. Measurements and Main Results: Significant differences in the 6-min walk distance, Borg dyspnea index, right ventricular stroke work index, and pulmonary artery pulsatility index were identified between patients with and without connective tissue disease associated pulmonary arterial hypertension. Patients with connective tissue disease had a lower right ventricular stroke work index, which was associated with decreased survival in this group; this association approached significance when adjusting for age and renal function. Conclusions: Right ventricular dysfunction as measured by right ventricular stroke work index is associated with decreased survival in patients with connective tissue disease associated pulmonary arterial hypertension despite similar pulmonary vascular resistance. These findings are suggestive of intrinsic right ventricular function in connective tissue disease associated pulmonary arterial hypertension that has a negative impact on the long-term survival of these individuals.

Combined Methods (Formal Adjusted Indirect Comparison, Meta-Analysis and Principal Component Analysis) Comparisons of the Safety and Efficacy of Ambrisentan, Bosentan, and Sildenafil in the Patients With Pulmonary Arterial Hypertension

BACKGROUND

Three oral drugs (ambrisentan, bosentan, and sildenafil) have been widely used to treat patients with pulmonary arterial hypertension (PAH). 1) There are no studies that directly compare the safety and efficacy of these three drugs. Existing studies could not meet the physician's need to select the most beneficial drugs for patients. 2) Principal component analysis is mainly used for scale analysis and has not been reported in clinical field. 3) When the results of the indirect meta-analysis were not satisfactory, no new solutions have been proposed in existing meta-analysis studies.

METHODS

The overall process of this study is divided into 4 steps 1) literature search and data extraction; 2) principal component analysis; 3) common reference-based indirect comparison meta-analysis; 4) formal adjusted indirect comparison.

RESULTS

Nine randomized controlled trials (RCTs) experiments and eight long-term experiments were selected. The main influencing factors are mortality, 6-min walk distance (6MW), mean pulmonary arterial pressure (PAP), cardiac index (CI) by principal component analysis. There was no significant heterogeneity among the indirect meta-analysis of three drugs. But in the formal adjusted indirect comparison 1) the level of PAP of sildenafil group (60.5 ± 22.35, 220) was higher than that of the other three groups, placebo (53.5 ± 17.63, 507) (p < 0.001), ambrisentan (49.5 ± 15.08, 130) (p < 0.001), and bosentan (54.6 ± 118.41, 311) (p < 0.001); 2) the level of CI of sildenafil group (54 ± 18, 311) was higher than that of the other three groups, placebo (2.7 ± 1.09, 518) (p < 0.001), ambrisentan (2.5 ± 0.75, 130) (p < 0.001), and bosentan (2.5 ± 1.06, 333) (p < 0.001). In addition, sildenafil significantly improved the survival rate comparing with ambrisentan and bosentan.

CONCLUSIONS

The results of this study suggest that sildenafil might be more suitable for long-term treatment of PAH patients than ambrisentan and bosentan. In order to enable clinicians to draw conclusions more quickly and directly in the data-rich literature, we suggest the use of principal component analysis combined with formal adjusted indirect comparison to compare the efficacy and safety of drugs.

Pulmonary Arterial Hypertension: A Palliative Medicine Review of the Disease, Its Therapies, and Drug Interactions

Pulmonary arterial hypertension (PAH) is often a progressive and ultimately fatal disease. It is characterized by an elevated mean pulmonary arterial pressure because of disease of the small pulmonary arterioles. PAH leads to a constellation of symptoms, including dyspnea, fatigue, syncope, chest discomfort, and peripheral edema. Disease-targeted therapies for PAH produce symptomatic and functional improvement, but long-term survival remains uncommon without lung transplantation. Palliative care is appropriate to support patients with advanced PAH who typically have a high symptom burden. However, palliative care has historically focused on supporting patients with malignant disease, rather than progressive chronic disease such as PAH. Our aim is to provide palliative care clinicians with a background in the classification, pathophysiology, and modern treatment of PAH. This review describes disease-targeted therapies and their effects on symptoms, physical functioning, and health-related quality of life. We also review the unique physiology of PAH and its implication for palliative interventions. Pharmacological interactions with, and precautions related to commonly used palliative care medications, are discussed.

Drug Treatment of Pulmonary Hypertension in Children

Pulmonary arterial hypertension (PAH) is a rare disease in infants and children that is associated with significant morbidity and mortality. The disease is characterized by progressive pulmonary vascular functional and structural changes resulting in increased pulmonary vascular resistance and eventual right heart failure and death. In many pediatric patients, PAH is idiopathic or associated with congenital heart disease and rarely is associated with other conditions such as connective tissue or thromboembolic disease. PAH associated with developmental lung diseases such as bronchopulmonary dysplasia or congenital diaphragmatic hernia is increasingly more recognized in infants and children. Although treatment of the underlying disease and reversal of advanced structural changes have not yet been achieved with current therapy, quality of life and survival have improved significantly. Targeted pulmonary vasodilator therapies, including endothelin receptor antagonists, prostacyclin analogs, and phosphodiesterase type 5 inhibitors have resulted in hemodynamic and functional improvement in children. The management of pediatric PAH remains challenging as treatment decisions depend largely on results from evidence-based adult studies and the clinical experience of pediatric experts. This article reviews the current drug therapies and their use in the management of PAH in children.

Management of Pulmonary Arterial Hypertension in Patients with Systemic Sclerosis

Systemic sclerosis (SSc) is a rare and complex immune-mediated connective tissue disease characterized by multi-organ fibrosis and dysfunction. Systemic sclerosis-associated pulmonary arterial hypertension (SSc-PAH) is a leading cause of death in this population. Pulmonary arterial hypertension (PAH) can coexist with other forms of pulmonary hypertension in SSc, including pulmonary hypertension related to left heart disease, interstitial lung disease, chronic thromboembolism and pulmonary venous occlusive disease, which further complicates diagnosis and management. Available pulmonary arterial hypertension therapies target the nitric oxide, endothelin and prostacyclin pathways. These therapies have been studied in SSc-PAH in addition to idiopathic PAH, often with different treatment responses. In this article, we discuss the management as well as the treatment options for patients with SSc-PAH.

Endothelin Receptor Antagonists: Status Quo and Future Perspectives for Targeted Therapy

The endothelin axis, recognized for its vasoconstrictive action, plays a central role in the pathology of pulmonary arterial hypertension (PAH). Treatment with approved endothelin receptor antagonists (ERAs), such as bosentan, ambrisentan, or macitentan, slow down PAH progression and relieves symptoms. Several findings have indicated that endothelin is further involved in the pathogenesis of certain other diseases, making ERAs potentially beneficial in the treatment of various conditions. In addition to PAH, this review summarizes the use and perspectives of ERAs in cancer, renal disease, fibrotic disorders, systemic scleroderma, vasospasm, and pain management. Bosentan has proven to be effective in systemic sclerosis PAH and in decreasing the development of vasospasm-related digital ulcers. The selective ERA clazosentan has been shown to be effective in preventing cerebral vasospasm and delaying ischemic neurological deficits and new infarcts. Furthermore, in the SONAR (Study Of Diabetic Nephropathy With Atrasentan) trial, the selective ERA atrasentan reduced the risk of renal events in patients with diabetes and chronic kidney disease. These data suggest atrasentan as a new therapy in the treatment of diabetic nephropathy and possibly other renal diseases. Preclinical studies regarding heart failure, cancer, and fibrotic diseases have demonstrated promising effects, but clinical trials have not yet produced measurable results. Nevertheless, the potential benefits of ERAs may not be fully realized.

Newer approaches and novel drugs for inhalational therapy for pulmonary arterial hypertension

Introduction: Pulmonary arterial hypertension (PAH) is a progressive disease characterized by remodeling of small pulmonary arteries leading to increased pulmonary arterial pressure. Existing treatments acts to normalize vascular tone via three signaling pathways: the prostacyclin, the endothelin-1, and the nitric oxide. Although over the past 20 years, there has been considerable progress in terms of treatments for PAH, the disease still remains incurable with a disappointing prognosis.Areas covered: This review summarizes the pathophysiology of PAH, the advantages and disadvantages of the inhalation route, and assess the relative advantages various inhaled therapies for PAH. The recent studies concerning the development of controlled-release drug delivery systems loaded with available anti-PAH drugs have also been summarized.Expert opinion: The main obstacles of current pharmacotherapies of PAH are their short half-life, stability, and formulations, resulting in reducing the efficacy and increasing systemic side effects and unknown pathogenesis of PAH. The pulmonary route has been proposed for delivering anti-PAH drugs to overcome the shortcomings. However, the application of approved inhaled anti-PAH drugs is limited. Inhalational delivery of controlled-release nanoformulations can overcome these restrictions. Extensive studies are required to develop safe and effective drug delivery systems for PAH patients.

Advances in medical therapy for pulmonary arterial hypertension

PURPOSE OF REVIEW

The purpose of this review is to demonstrate advances in the medical treatment of pulmonary arterial hypertension (PAH). Reviewed will be the evidence that favors the use of risk assessment in the treatment of PAH. Optimization of combination therapy depending on the risk or worsening will be reviewed. Finally, recent advances in new treatment strategies will be mentioned.

RECENT FINDINGS

The use of therapies in sequence or in combination for the treatment of PAH has been shown to decrease morbidity and mortality. Tailoring these treatment strategies to a risk of worsening has been shown to decrease mortality and time to clinical worsening because of PAH. In addition, there have been several advances in the development of other medications separate from the three known pathogenic pathways in PAH.

SUMMARY

In the last 15 years, 12 specific therapies have been approved for PAH. These therapies target three separate pathogenic pathways [the endothelin (ET), nitric oxide (NO) and prostacyclin (PGI2)]. As a result, treatment guidelines have tailored the treatment of PAH with these medications either as single drug therapy or in combination. Recently, other treatment pathways have been explored as new strategies for the treatment of PAH.

Established and emerging therapeutic uses of PDE type 5 inhibitors in cardiovascular disease

PDE type 5 inhibitors (PDE5Is), such as sildenafil, tadalafil and vardenafil, are a class of drugs used to prolong the physiological effects of NO/cGMP signalling in tissues through the inhibition of cGMP degradation. Although these agents were originally developed for the treatment of hypertension and angina, unanticipated side effects led to advances in the treatment of erectile dysfunction and, later, pulmonary arterial hypertension. In the last decade, accumulating evidence suggests that PDE5Is may confer a wider range of clinical benefits than was previously recognised. This has led to a broader interest in the cardiovascular therapeutic potential of PDE5Is, in conditions such as hypertension, myocardial infarction, stroke, peripheral arterial disease, chronic kidney disease and diabetes mellitus. Here, we review the pharmacological properties and established licensed uses of this class of drug, along with emerging therapeutic developments and possible future indications.

Endothelins in cardiovascular biology and therapeutics

Cardiovascular disease is a major contributor to global morbidity and mortality and is the common end point of many chronic diseases. The endothelins comprise three structurally similar peptides of 21 amino acids in length. Endothelin 1 (ET-1) and ET-2 activate two G protein-coupled receptors - endothelin receptor type A (ET_A) and endothelin receptor type B (ET_B) - with equal affinity, whereas ET-3 has a lower affinity for ET_A. ET-1 is the most potent vasoconstrictor in the human cardiovascular system and has remarkably long-lasting actions. ET-1 contributes to vasoconstriction, vascular and cardiac hypertrophy, inflammation, and to the development and progression of cardiovascular disease. Endothelin receptor antagonists have revolutionized the treatment of pulmonary arterial hypertension. Clinical trials continue to explore new applications of endothelin receptor antagonists, particularly in treatment-resistant hypertension, chronic kidney disease and patients receiving antiangiogenic therapies. Translational studies have identified important roles for the endothelin isoforms and new therapeutic targets during development, in fluid-electrolyte homeostasis, and in cardiovascular and neuronal function. Novel pharmacological strategies are emerging in the form of small-molecule epigenetic modulators, biologics (such as monoclonal antibodies for ET_B) and possibly signalling pathway-biased agonists and antagonists.

Sustainable synthesis of ambrisentan – syringic acid cocrystal: employing mechanochemistry in the development of novel pharmaceutical solid form

Development of the pharmaceutical cocrystal of ambrisentan with syringic acid via mechanochemistry as a greener and sustainable methodology with improved biopharmaceutical parameters.

Comparative effectiveness of pulmonary arterial hypertension drugs in treatment-naive patients: a network meta-analysis

Aim: No network meta-analysis has been conducted to study efficacy of drug therapies specific for treatment of pulmonary arterial hypertension in treatment-naive patients only. Methods: Randomized controlled trials on pulmonary arterial hypertension-specific drug therapies were searched and a Bayesian network meta-analysis was performed. The 6-min walking distance (6MWD) and all-cause mortality were efficacy outcomes, whereas discontinuation due to adverse events was a safety-related outcome. Results: Analysis included 3.713 patients from 21 trials. Combination of ambrisentan and tadalafil showed the greatest impact on 6MWD, followed by epoprostenol and intravenous treprostinil (high dose). The latter two demonstrated marked effect size on mortality, although not statistically significant. Conclusion: According to 6MWD, ambrisentan/tadalafil combination was considered as most effective among all comparisons. Prospero ID: CRD42019110832.

Pulmonary Hypertension in HIV

Human immunodeficiency virus-associated pulmonary arterial hypertension (HIV-PAH) is important to recognize given its association with significant morbidity and mortality. With the introduction of antiretroviral therapy, the focus of disease management has largely shifted from treating immunodeficiency-related opportunistic infections to managing chronic cardiopulmonary complications. Symptoms are nonspecific, and a high index of clinical suspicion is needed to avoid significant delay in the diagnosis of HIV-PAH. Although several viral proteins have been implicated in the pathogenesis of HIV-PAH, the exact mechanism remains uncertain. Further studies are needed to elucidate precise pathogenic mechanisms, early diagnostic tools, and novel therapeutic targets to improve prognosis of this severe complication.

Therapeutic Challenges And Advances In The Management Of Systemic Sclerosis-Related Pulmonary Arterial Hypertension (SSc-PAH)

Systemic sclerosis (SSc) is a rare autoimmune disorder with multi-organ involvement. SSc-associated pulmonary arterial hypertension (SSc-PAH) is one of the leading causes of morbidity and mortality in the SSc population. With advances in our understanding of pulmonary arterial hypertension (PAH) diagnosis and treatment, outcomes for all PAH patients have significantly improved. While SSc-PAH patients have also benefited from these advances, significant challenges remain. Diagnosis of PAH is a challenging endeavor in SSc patients who often have many co-existing pulmonary and cardiac comorbidities. Given the significantly elevated prevalence and lifetime risk of PAH in the SSc population, screening for SSc-PAH is a critically useful strategy. Treatment with pulmonary arterial (PA) vasodilators has resulted in a dramatic improvement in the survival and quality of life of PAH patients. While therapy with PA vasodilators is beneficial in SSc-PAH patients, therapy effects appear to be attenuated when compared to responses in patients with idiopathic PAH (IPAH). This review attempts to chronicle and summarize the advances in our understanding of the optimal screening strategies to identify PAH in patients with SSc. The article also reviews the advances in the therapeutic and risk stratification strategies for SSc-PAH patients.

Pulmonary arterial hypertension: the case for a bioelectronic treatment

Pulmonary arterial hypertension (PAH) is a rare disease of unknown etiology that progresses to right ventricular failure. It has a complex pathophysiology, which involves an imbalance between vasoconstrictive and vasodilative processes in the pulmonary circulation, pulmonary vasoconstriction, vascular and right ventricular remodeling, systemic inflammation, and autonomic imbalance, with a reduced parasympathetic and increased sympathetic tone. Current pharmacological treatments for PAH include several classes of drugs that target signaling pathways in vascular biology and cardiovascular physiology, but they can have severe unwanted effects and they do not typically stop the progression of the disease. Pulmonary artery denervation has been tested clinically as a method to suppress sympathetic overactivation, however it is a nonspecific and irreversible intervention. Bioelectronic medicine, in particular vagus nerve stimulation (VNS), has been used in cardiovascular disorders like arrhythmias, heart failure and arterial hypertension and could, in principle, be tested as a treatment in PAH. VNS can produce pulmonary vasodilation and renormalize right ventricular function, via activation of pulmonary and cardiac vagal fibers. It can suppress systemic inflammation, via activation of fibers that innervate the spleen. Finally, VNS can gradually restore the balance between parasympathetic and sympathetic tone by regulating autonomic reflexes. Preclinical studies support the feasibility of using VNS in PAH. However, there are challenges with such an approach, arising from the need to affect a relatively small number of relevant vagal fibers, and the potential for unwanted cardiac and noncardiac effects of VNS in this sensitive patient population.