Effects of sotatercept on haemodynamics and right heart function: analysis of the STELLAR trial

Sotatercept in pulmonary hypertension and beyond

Sotatercept binds free activins by mimicking the extracellular domain of the activin receptor type IIA (ACTRIIA). Additional ligands are BMP/TGF-beta, GDF8, GDF11 and BMP10. The binding with activins leads to the inhibition of the signalling pathway and the deactivation of the bone morphogenic protein (BMP) receptor type 2. In this way, sotatercept activates an antiproliferative signalling to the cells of the pulmonary arteries and arterioles with the aim of rebalancing the proliferative and antiproliferative pathway that characterizes the pulmonary arterial hypertension (PAH). Sotatercept is indicated for the treatment of group 1 PAH in combination with drugs that act through the endothelin receptor, nitric oxide or prostacyclin. Its effects, demonstrated in the STELLAR study, are the improvement of exercise capacity and the FC-WHO functional class, together with the reduction of the risk of clinical worsening events. In addition to its antiremodeling effects on the pulmonary circulation, sotatercept has several haematological effects that could suggest its use in the treatment of some blood disorders other than PAH. In this review, we will discuss the effects of the drug on PAH and in parallel provide an in-depth overview of its application in haematological disorders, focusing on clinical and preclinical studies.

Effects of β-Blockers on the Outcomes in Patients With Pulmonary Arterial Hypertension Stratified by the Presence of Comorbid Conditions: A Multicenter Prospective Cohort Study: The Database of Pulmonary Hypertension in the Polish Population (BNP-PL)

BACKGROUND

Current guidelines do not recommend β-blockers in pulmonary arterial hypertension (PAH) unless indicated by comorbidities. However, the evidence regarding the role of β-blockers in PAH is contradictory.

RESEARCH QUESTION

What are the effects of β-blockers on clinical outcomes in patients newly diagnosed with PAH, and how do these outcomes differ based on the presence of cardiovascular comorbidities that are standard indications for β-blocker use?

STUDY DESIGN AND METHODS

We analyzed data from 806 patients newly diagnosed with PAH enrolled prospectively in the Database of Pulmonary Hypertension in the Polish Population (BNP-PL). The end points were all-cause mortality and a composite of hospitalization due to right-sided heart failure, syncope, or death. Indications for β-blocker use included hypertension, significant arrhythmia, and coronary artery disease. Propensity score matching was used to form a control group based on age, PAH mortality risk variables, and initially introduced PAH-specific therapy.

RESULTS

Of the 806 patients, 469 (58.2%) received β-blockers at the time of PAH diagnosis. In propensity score matching, β-blocker treatment showed a higher incidence of the composite end point (hazard ratio, 1.44; 95% CI, 1.04-1.99; P = .03) and had a neutral impact on mortality (hazard ratio, 1.22; 95% CI, 0.87-1.72; P = .25). When stratified according to the presence of comorbidities, β-blockers showed adverse effects on the composite end point in patients without comorbidities and a neutral effect in patients with at least one comorbidity.

INTERPRETATION

Our results indicate that β-blockers pose significant risks in patients with PAH, especially in patients without coexisting systemic hypertension, coronary artery disease, or arrhythmia.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT03959748; URL: www.

CLINICALTRIALS

gov.

Efficacy and safety of sotatercept across ranges of cardiac index in patients with pulmonary arterial hypertension: A pooled analysis of PULSAR and STELLAR

BACKGROUND

This analysis examined the effects of the activin signaling inhibitor, sotatercept, in pulmonary arterial hypertension (PAH) subgroups stratified by baseline cardiac index (CI).

METHODS

Pooled data from PULSAR (N = 106; NCT03496207) and STELLAR (N = 323; NCT04576988) were analyzed using 2 different CI thresholds, <2.0 and ≥2.0 liter/min/m2 as well as <2.5 and ≥2.5 liter/min/m2. Median changes from baseline at week 24 were evaluated using Hodges-Lehmann estimator and least squares (LS) means, with 95% confidence intervals and p-values (significance: p = 0.05). Categorial endpoints and time-to-clinical worsening were analyzed by Cochran-Mantel-Haenszel and Cox model respectively.

RESULTS

Of 429 participants, 51 had CI <2.0 and 378 ≥2.0 liter/min/m2, while 179 had CI <2.5 and 250 ≥2.5 liter/min/m2. Sotatercept significantly improved median 6-minute walk distance (range: 33.9 to 63.7 m: p < 0.001), pulmonary vascular resistance (range: -202.8 to -395.4 dyn•s•cm-5; p ≤ 0.002), and N-terminal pro-B-type natriuretic peptide (range: -317.3 to -1,041.2 pg/ml; p < 0.001) across subgroups. LS means showed reductions in pulmonary and right atrial pressures, decreased right ventricular size, and improved tricuspid annular plane systolic excursion/systolic pulmonary artery pressure. Sotatercept delayed time to first occurrence of death or a worsening event for CI ≥2.5 (hazard ratio [HR] 0.12; p < 0.001), ≥2.0 (HR 0.13; p < 0.001), and <2.5 (HR 0.21; p < 0.001) liter/min/m2. Improvements were observed in WHO functional class (all p < 0.050) and ESC/ERS risk scores (all p < 0.001).

CONCLUSIONS

Sotatercept demonstrated consistent efficacy and safety across CI subgroups, supporting its use in PAH patients irrespective of baseline cardiac hemodynamics.

Right heart reverse remodeling: "facta non verba "

Pulmonary arterial hypertension (PAH) is characterized by pulmonary vascular remodeling and arterial narrowing, leading to a progressive rise in right ventricular (RV) afterload and poor survival outcomes. PAH prognosis largely depends on RV remodeling and function: when the increased afterload exceeds the RV's adaptive capacity, ventricular-arterial uncoupling occurs, ultimately causing right heart failure and death. In this clinical setting the primary treatment goal is to achieve low mortality risk and right heart reverse remodeling (RHRR). Unfortunately, the definition of RHRR vary across studies and imaging modalities (echocardiography or Cardiac Magnetic Resonance). The likelihood of RHRR increases with a significant reduction in pulmonary vascular resistance (PVR) from baseline, ideally by at least 50 %. Evidence supports initial triple therapy, including parenteral prostanoids, as the most effective approach to reduce PVR enough to facilitate RHRR and thus achieve the low-risk status.

Population Pharmacokinetic/Pharmacodynamic and Exposure-Response Modeling Analyses of Sotatercept in Healthy Participants and Patients with Pulmonary Arterial Hypertension

Sotatercept is a breakthrough, first-in-class biologic, recently approved by the Food and Drug Administration (FDA) for the treatment of pulmonary arterial hypertension (PAH). Exposure-response (E-R) analyses and pharmacokinetic/pharmacodynamic (PK/PD) modeling were performed for sotatercept after intravenous and subcutaneous (SC) administrations. Clinical endpoints included 6-minute walk distance (6MWD), pulmonary vascular resistance (PVR), and probability of N-terminal pro-B natriuretic peptide (NT-proBNP) concentrations < 300 pg/mL for efficacy, and hemoglobin (Hgb) for safety from two Phase 1 studies, two Phase 2 studies, and one Phase 3 study. E-R models using nonlinear mixed effect modeling approach were developed for 6MWD and PVR, while Cox proportional hazards model and semi-mechanistic PK/PD model were used for NT-proBNP and Hgb. Covariate analyses were conducted to identify significant predictors of variability for each of these clinical endpoints. Modeling results showed that increasing sotatercept average concentration (Cavg) at week 24 is associated with increased predicted 6MWD, increased probability of NT-proBNP concentration < 300 pg/mL, decreased predicted PVR, and increased Hgb which was clinically manageable. All these responses approached their corresponding plateaus at a Cavg range associated with the dose of 0.7 mg/kg Q3W SC. Statistically relevant covariates included age and iron supplementation which slightly increased Hgb-mediated effect for 6MWD, PAH disease duration, and baseline therapy infusion with prostacyclin for PVR, and WHO functional class for NT-proBNP. The magnitudes of the impact of these covariates are not clinically meaningful. Taken together, these results support an appropriate benefit-risk profile for the FDA-approved target dose for sotatercept of 0.7 mg/kg Q3W SC.

Revisiting treatment of pulmonary arterial hypertension in the current era: a Greek scientific document

Pulmonary arterial hypertension (PAH) is a life-threatening condition characterised by the excessive proliferation of pulmonary artery vessels. Despite significant advancements in treatment strategies over recent years, mortality rates remain high. The current treatment strategy focuses on risk assessment both at the time of diagnosis and during follow-up. It involves the initial use of combination therapies targeting PAH. These therapies regulate vascular tone through 3 main pathways: the endothelin pathway, the nitric oxide/cyclic guanosine monophosphate pathway, and the prostacyclin pathway. Sotatercept, a fusion protein that binds to ligands of the transforming growth factor-β superfamily, rebalances the pro- and anti-proliferative signalling of activin receptor type II (A/B), thus targeting a unique pathogenic pathway and promoting anti-proliferative effects on the pulmonary vasculature. Recently, it received approval from the European Medicines Agency for patients with PAH classified as World Health Organisation functional class II or III. Proceedings from the latest World Symposium on Pulmonary Hypertension stress the importance of adding sotatercept to the treatment regimen for the majority of patients during follow-up, including those at high risk. In anticipation of upcoming scientific guidelines and with the hope of improved outcomes for patients with PAH, an expert opinion for the treatment of Greek patients has been developed, focusing on the integration of this novel agent into the therapeutic algorithm.

Identification of an immune-related gene panel for the diagnosis of pulmonary arterial hypertension using bioinformatics and machine learning

OBJECTIVE

This study aimed to screen an immune-related gene (IRG) panel and develop a novel approach for diagnosing pulmonary arterial hypertension (PAH) utilizing bioinformatics and machine learning (ML).

METHODS

Gene expression profiles were retrieved from the Gene Expression Omnibus (GEO) database to identify differentially expressed immune-related genes (IRG-DEGs). We employed five machine learning algorithms-LASSO, random forest (RF), boosted regression trees (BRT), XGBoost, and support vector machine recursive feature elimination (SVM-RFE) to identify biomarkers derived from IRG-DEGs associated with the diagnosis of PAH, incorporating them into the IRG-DEGs panel. Validation of these biomarker levels in lung tissue was conducted in a hypoxia-induced mouse model of PAH, investigating the correlation between AIMP1, IL-15, GLRX, SOD1, Fulton's index (RVHI), and the ratio of pulmonary artery medial thickness to external diameter (MT%). Subsequently, we developed a nomogram model based on the IRG-DEGs panel in lung tissue for diagnosing PAH. The expression, distribution, and pseudotime analysis of these biomarkers across various immune cell types were assessed using single-cell sequencing datasets. Finally, we evaluated the diagnostic utility of the nomogram model based on the IRG-DEGs panel in peripheral blood mononuclear cells (PBMCs) for diagnosing PAH.

RESULTS

A total of 36 upregulated and 17 downregulated IRG-DEGs were identified in lung tissue from patients with PAH. AIMP1, IL-15, GLRX, and SOD1 were subsequently selected as novel immune-related biomarkers for PAH through the aforementioned machine learning algorithms and incorporated into the IRG-DEGs panel. Experimental results from mice with PAH validated that the expression levels of AIMP1, IL-15, and GLRX in lung tissue were elevated, while SOD1 expression was significantly reduced. Additionally, GLRX and AIMP1 exhibited positive correlations with Fulton's index (RVHI). The expression levels of GLRX, IL-15, and AIMP1 showed positive correlations with MT%, whereas SOD1 exhibited negative correlations with MT%. Analysis of single-cell sequencing data further revealed that the levels of IRG-DEG panel members gradually increased during the pseudotime trajectory from PBMCs to macrophages, correlating with macrophage activation. The area under the curve (AUC) for diagnosing PAH using a nomogram model based on the IRG-DEGs panel derived from lung tissue samples and PBMCs was ≥0.969 and 0.900, respectively.

CONCLUSIONS

We developed an IRG-DEGs panel containing AIMP1, IL-15, GLRX, and SOD1, which may facilitate the diagnosis of pulmonary arterial hypertension (PAH). These findings provide novel insights that may enhance diagnostic and therapeutic approaches for PAH.

Sotatercept: A New Era in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a progressive disease characterized by proliferative remodeling and obliterative narrowing of the pulmonary vasculature. While outcomes have improved with existing treatments targeting 3 main pathways, there remains a critical need for novel therapies that address different and novel mechanisms of PAH. Sotatercept, recently Food and Drug Administration (FDA) approved, is a groundbreaking fusion protein that binds to activin and growth differentiation factors, rebalancing antiproliferative and pro-proliferative signals to reverse remodeling in both the pulmonary vasculature and the right ventricle. This review highlights current evidence exploring the safety and efficacy of sotatercept in the 2 landmark trials, phase 2 Pulmonary Arterial Hypertension and Sotatercept Trial and Research and phase 3 Sotatercept Treatment in Expansion of Long-term Learning and Assessment in PAH trial, which were instrumental in securing FDA approval for adult PAH patients with WHO functional class II or III symptoms already receiving background pulmonary hypertension therapy. Overall, sotatercept represents a landmark advancement in PAH treatment, offering hope for patients and the potential to delay or avoid lung transplantation. Importantly, this marks the beginning of an era of targeted therapies aimed at reverse remodeling in PAH while improving outcomes.

PET/CT Imaging of the Right Heart Perfusion and Glucose Metabolism Depending on a Risk Status in Patients With Idiopathic Pulmonary Arterial Hypertension

Right ventricular heart failure (RV HF) is the leading cause of death in pulmonary arterial hypertension (PAH). Relevance of the low-risk status assessment using available diagnostic tools requires a reliable confirmation. The study aimed to evaluate right ventricular perfusion and glucose metabolism using positron emission tomography (PET)/computed tomography (CT) with [13N]-ammonia and [18F]-fluorodeoxyglucose ([18F]-FDG) in 30 IPAH patients (33.8 ± 9.4 years) according to ESC/ERS 2022 risk status. The ratio of SUVmaxRV/LV metabolism and SUVmaxRV/LV perfusion showed significant positive correlation with pulmonary artery pressure, right heart dilatation, NT-proBNP level and negative correlation with the RV ejection fraction. The SUVmaxRV/LV perfusion and SUVmaxRV/LV metabolism ratios differed significantly according to risk status. Low risk patients had a SUVmaxRV/LV metabolism comparable to the controls without PH. The SUVmaxRV/LV perfusion ratio was elevated in low-risk IPAH patients compared with controls. Increased SUVmaxRV/LV perfusion may be an early marker of coronary flow adaptation to RV pressure overload in low-risk IPAH patients and requires further evaluation. Further long-term studies are needed to determine the clinical relevance and cut-off values for the RV/LV PET/CT with [13N]-ammonia and [18F]-fluorodeoxyglucose ([18F]-FDG) uptake in different IPAH risk groups.

A new day has come: Sotatercept for the treatment of pulmonary arterial hypertension

Despite increasing therapeutic options and evolving treatment strategies, including targeting 3 therapeutic pathways, in the management of pulmonary arterial hypertension (PAH), morbidity and mortality have remained unacceptably high. Sotatercept is a first-in-class, novel activin signaling inhibitor approved for treating PAH based on evolving efficacy and safety evidence. This state-of-the-art review summarizes the current understanding of the mechanism of action, the impact on outcomes that improve how patients feel, function, and survive, and the safety and adverse event profile to inform readers of this breakthrough novel therapy.

Sotatercept: New drug on the horizon of pulmonary hypertension

Sotatercept (brand name WINREVAIR, developed by Merck) is an activin receptor type IIA-Fc (ActRIIA-Fc), working by sequestering free activins. Sotatercept restores the balance between the activin proliferative pathway and the bone morphogenic protein (BMP) antiproliferative pathway in the pulmonary arterial cirulation. Sotatercept recently received approval in the USA and in Europe for the treatment of adults with pulmonary arterial hypertension (PAH) Group 1, on top of background PAH therapy to increase exercise capacity, improve WHO functional class and reduce the risk of clinical worsening events. Nevertheless, several studies are ongoing to investigate the potential adverse reactions of the drug especially at the haematological level. We provide an overview of the clinical and preclinical evidence of the targeting the activing pathway through sotatercept on the treatment of PAH. We also discuss what other possibilities there are for the application of sotatercept in the setting of pulmonary hypertension other than PAH Group 1.

Gaps in evidence in the treatment of prevalent patients with pulmonary arterial hypertension at intermediate risk: An expert consensus

Despite the innovations introduced in the 2022 European Society of Cardiology/European Respiratory Society Guidelines on Pulmonary Hypertension, risk discrimination and management of pulmonary arterial hypertension (PAH) patients at intermediate risk still represents a grey zone. Additionally, clinical evidence derived from currently available studies is limited. This expert panel survey intends to aid physicians in choosing the best therapeutic strategy for patients at intermediate risk despite ongoing oral therapy. An expert panel of 24 physicians, specialized in cardiology and/or pulmonology with expertise in handling all drugs available for the treatment of PAH participated in the survey. All potential therapeutic options for patients at intermediate risk were explored and analyzed to produce graded consensus statements regarding: the switch from endothelin receptor antagonist (ERA) or phosphodiesterase 5 inhibitor (PDE5i) to another oral drug of the same class; the addition of a drug targeting the prostacyclin pathway administered by different routes; the switch from PDE5i to riociguat.

The acute effect of high-dose supplemental oxygen on haemodynamics assessed by echocardiography in patients with pulmonary vascular disease living in Quito at 2850 m: a randomized, single-blind, placebo-controlled crossover trial

Aims

More than 220 Mio people live at altitudes above 2000 m, many of whom have pre-existing chronic diseases, including pulmonary vascular diseases (PVDs) such as pulmonary arterial hypertension (PAH) or chronic thromboembolic pulmonary hypertension (CTEPH). We investigated the acute effects of high-dose supplemental oxygen on pulmonary haemodynamics assessed by echocardiography in patients with PVD permanently living at 2850 m.

Methods and results

In a randomized, single-blind, placebo-controlled crossover trial, patients with PVD diagnosed with PAH or CTEPH were allocated to receive 10 L/min supplemental oxygen (FiO2 ≈ 95%) and placebo air administered via a facial mask with reservoir near their living altitude in Quito at 2850 m (FiO20.21, PiO2 ≈ 60% of sea level) in random order with a washout period of >2 h. After >15 min of breathing the respective FiO2, systolic pulmonary artery pressure (sPAP), cardiac output (CO), and other parameters were assessed by echocardiography. Furthermore, radial arterial blood gases were analysed. Twenty-eight patients with PVD (24 females, 26 PAH, age 45 ± 12 years) treated with phosphodiesterase-5 inhibitors (n = 28) and endothelin receptor antagonists (n = 9) were included. With oxygen vs. placebo air, sPAP was 57 ± 23 vs. 68 ± 24 mmHg, mean difference -11 mmHg (-15 to -6 mmHg, P < 0.001), CO was 3.2 ± 0.9 vs. 3.9 ± 1.1 L/min; -0.7 L/min (-0.9 to -0.4 L/min, P < 0.001), while sPAP/CO was unchanged, and the right ventriculo-arterial coupling was increased. PaO2 was 22.5 ± 9.7 vs. 7.6 ± 1.5 kPa; 14.9 kPa (11.4-18.4 kPa, P < 0.001).

Conclusion

High-dose oxygen therapy in prevalent patients with PVD living near 2850 m significantly lowered sPAP but also CO by a reduced heart rate, resulting in an unchanged pulmonary resistance. Whether longer-term oxygen therapy would improve pulmonary vascular resistance requires further investigation.

Registration

NCT06084559 URL: https://clinicaltrials.gov/study/NCT06084559.

Circulating biomarkers in pulmonary arterial hypertension: State-of-the-art review and future directions

Pulmonary arterial hypertension is a complex and heterogeneous condition, associated with a considerable diagnostic delay, diminished exercise capacity, and poor outcomes. In pulmonary arterial hypertension, biomarker research has become a subject of intense inquiry, and novel circulating biomarkers acknowledged in a multitude of mechanistic pathways are emerging. Beyond the widely used natriuretic peptides, novel biomarkers may provide deeper pathophysiological understanding, support clinical decision-making, and prompt the incorporation of precision medicine by enabling a more precise individual phenotyping. In this state-of-the-art review, the recent advances in circulating biomarkers in pulmonary arterial hypertension from a clinical perspective are discussed, with particular emphasis on the current state of knowledge, gaps in evidence, and future perspectives.

A Belgian consensus on sotatercept for the treatment of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a rare disease affecting the small pulmonary vessels, ultimately leading to right ventricular failure and death. Current treatment options target three different pathways (endothelin, nitric oxide/cGMP and prostacyclin pathways). Despite their demonstrated efficacy, these therapies (commonly used in combination) do not cure the disease which is why novel pathways beyond the traditional 'big three' are being developed. Sotatercept is a ligand trap for multiple proteins within the TGF-β superfamily that was recently approved in the US for the treatment of PAH. Unlike currently available therapies, sotatercept has the potential to act as an anti-remodelling agent rather than a vasodilator. The safety and efficacy of subcutaneous (SC) sotatercept have been established in two multicentre, placebo-controlled randomised-controlled trials. The compound has been shown to consistently improve a variety of measurable endpoints, including exercise capacity, haemodynamics, quality of life and delay of clinical worsening. The drug appears to have an acceptable safety profile, although it is associated with an increased risk in developing telangiectasia and biological changes affecting platelet counts and haemoglobin. This study reviews the current evidence on SC sotatercept and provides a Belgian perspective on its place in the future treatment strategy for PAH.

Perspectives on Sotatercept in Pulmonary Arterial Hypertension

Sotatercept acts as a type IIA-Fc activin receptor, thereby scavenging free activin from its physiological membrane receptor. Through this type of action, sotaterpect leads to a rebalancing of the proliferation and antiproliferation pathways of pulmonary smooth muscle cells in response to bone morphogenic protein (BMP). Although sotatercept has been approved as the fourth pillar of therapy for group 1 pulmonary arterial hypertension (PAH) in the United States and Europe, several studies are ongoing to broaden the application of the drug to non-Group 1 PAH. We provide an overview of the clinical and preclinical evidence of targeting the activation pathway by sotatercept in the treatment of PAH. We also discuss other potential applications of sotatercept in the context of pulmonary hypertension other than PAH group 1.

Pathophysiology of the right ventricle and its pulmonary vascular interaction

The right ventricle and its stress response is perhaps the most important arbiter of survival in patients with pulmonary hypertension of many causes. The physiology of the cardiopulmonary unit and definition of right heart failure proposed in the 2018 World Symposium on Pulmonary Hypertension have proven useful constructs in subsequent years. Here, we review updated knowledge of basic mechanisms that drive right ventricular function in health and disease, and which may be useful for therapeutic intervention in the future. We further contextualise new knowledge on assessment of right ventricular function with a focus on metrics readily available to clinicians and updated understanding of the roles of the right atrium and tricuspid regurgitation. Typical right ventricular phenotypes in relevant forms of pulmonary vascular disease are reviewed and recent studies of pharmacological interventions on chronic right ventricular failure are discussed. Finally, unanswered questions and future directions are proposed.

Management of pulmonary hypertension in special conditions

Care of pulmonary hypertension (PH) patients in special situations requires insightful knowledge of the pathophysiology of the cardiopulmonary system and close interaction with different specialists, depending on the situation. The role of this task force was to gather knowledge about five conditions that PH patients may be faced with. These conditions are 1) perioperative care; 2) management of pregnancy; 3) medication adherence; 4) palliative care; and 5) the influence of climate on PH. Many of these aspects have not been covered by previous World Symposia on Pulmonary Hypertension. All of the above conditions are highly affected by psychological, geographical and socioeconomic factors, and share the need for adequate healthcare provision. The task force identified significant gaps in information and research in these areas. The current recommendations are based on detailed literature search and expert opinion. The task force calls for further studies and research to better understand and address the special circumstances that PH patients may encounter.

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.

Risk stratification and treatment goals in pulmonary arterial hypertension

Risk stratification has gained an increasing role in predicting outcomes and guiding the treatment of patients with pulmonary arterial hypertension (PAH). The most predictive prognostic factors are three noninvasive parameters (World Health Organization functional class, 6-min walk distance and natriuretic peptides) that are included in all currently validated risk stratification tools. However, suffering from limitations mainly related to reduced specificity of PAH severity, these variables may not always be adequate in isolation for guiding individualised treatment decisions. Moreover, with effective combination treatment regimens and emerging PAH therapies, markers associated with pulmonary vascular remodelling are expected to become of increasing relevance in guiding the treatment of patients with PAH. While reaching a low mortality risk, assessed with a validated risk tool, remains an important treatment goal, preliminary data suggest that invasive haemodynamics and cardiac imaging may add incremental value in guiding treatment decisions.

Diagnosis and Management of Pulmonary Hypertension: New Insights

Over the last decades, significant progress has been achieved in the pulmonary hypertension (PH) field. Pathophysiology of PH has been studied, leading to the classification of PH patients into five groups, while the hemodynamic definition has been recently revised. A diagnostic algorithm has been established and awareness has been raised in order to minimize diagnosis delay. The pulmonary arterial hypertension (PAH) treatment strategy includes the established three pathways of endothelin, nitric oxide-phosphodiesterase inhibitor, and prostacyclin pathway, but new therapeutic options are now being tested. The aim of this review is to summarize the existing practice and to highlight the novelties in the field of PH.

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.

Risk stratification refinements with inclusion of haemodynamic variables at follow-up in patients with pulmonary arterial hypertension

BACKGROUND

Haemodynamic variables are prognostic factors in pulmonary arterial hypertension (PAH). However, right heart catheterisation (RHC) is not systematically recommended to assess the risk status during follow-up. This study aimed to assess the added value of haemodynamic variables in prevalent patients to predict the risk of death or lung transplantation according to their risk status assessed by the non-invasive four-strata model as recommended by the European guidelines.

METHODS

We evaluated incident patients with PAH enrolled in the French pulmonary hypertension registry between 2009 and 2020 who had a first follow-up RHC. Cox regression identified, in each follow-up risk status, haemodynamic variables significantly associated with transplant-free survival. Optimal thresholds were determined by time-dependent receiver operating characteristics. Several multivariable Cox regression models were performed to identify the haemodynamic variables improving the non-invasive risk stratification model.

RESULTS

We analysed 1240 incident patients reassessed within 1 year by RHC. None of the haemodynamic variables were significantly associated with transplant-free survival among low-risk (n=386) or high-risk (n=71) patients. Among patients at intermediate (intermediate-low, n=483 and intermediate-high, n=300) risk at first follow-up, multivariable models including either stroke volume index (SVI) or mixed venous oxygen saturation (S vO2 ) were the best. The prognostic performance of a refined six-strata risk stratification model including the non-invasive four-strata model and SVI >37 mL·m-2 and/or S vO2 >65% for patients at intermediate risk (area under the curve (AUC) 0.81; c-index 0.74) was better than that of the four-strata model (AUC 0.79, p=0.009; c-index 0.72).

CONCLUSION

Cardiopulmonary haemodynamics may improve risk stratification at follow-up in patients at intermediate risk.

Using Sotatercept in the Care of Patients With Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a rare disease of the pulmonary microvasculature leading to elevated precapillary pulmonary hypertension. Pulmonary vascular remodeling, a characteristic of PAH, is driven by dysfunctions in the signaling between the pulmonary smooth muscle and endothelial cells with abnormalities that affect cell proliferation and immune dysregulation. Sotatercept, an activin signaling inhibitor, has recently been approved by the US Food and Drug Administration for the treatment of PAH based on two pivotal clinical trials. Evidence-based clinical trials have provided a framework to guide clinicians treating the disease; however, they are not tailored to the individual patient. Often, recommendations from these data are unclear or too general, due to remaining gaps in knowledge. In this edition of "How I Do It," we provide a case-based discussion of common clinical decisions regarding diagnostic testing, choice of first-line agents, escalation of therapy, potential timing of sotatercept, safety awareness, practical use, potential management changes, and the future use of sotatercept in other pulmonary hypertension cohorts.

The Relevance of the Endothelium in Cardiopulmonary Disorders

The endothelium is a cell monolayer that lines vessels and separates tissues from blood flow. Endothelial cells (ECs) have a multitude of functions, including regulating blood flow and systemic perfusion through changes in vessel diameter. When an injury occurs, the endothelium is affected by altering its functions and structure, which leads to endothelial dysfunction, a characteristic of many vascular diseases. Understanding the role that the endothelium plays in pulmonary vascular and cardiopulmonary diseases, and exploring new therapeutic strategies is of utmost importance to advance clinically. Currently, there are several treatments able to improve patients' quality of life, however, none are effective nor curative. This review examines the critical role of the endothelium in the pulmonary vasculature, investigating the alterations that occur in ECs and their consequences for blood vessels and potential molecular targets to regulate its alterations. Additionally, we delve into promising non-pharmacological therapeutic strategies, such as exercise and diet. The significance of the endothelium in cardiopulmonary disorders is increasingly being recognized, making ECs a relevant target for novel therapies aimed at preserving their functional and structural integrity.

Immunotherapy for Pulmonary Arterial Hypertension: From the Pathogenesis to Clinical Management

Pulmonary hypertension (PH) is a progressive cardiovascular disease, which may lead to severe cardiopulmonary dysfunction. As one of the main PH disease groups, pulmonary artery hypertension (PAH) is characterized by pulmonary vascular remodeling and right ventricular dysfunction. Increased pulmonary artery resistance consequently causes right heart failure, which is the major reason for morbidity and mortality in this disease. Although various treatment strategies have been available, the poor clinical prognosis of patients with PAH reminds us that further studies of the pathological mechanism of PAH are still needed. Inflammation has been elucidated as relevant to the initiation and progression of PAH, and plays a crucial and functional role in vascular remodeling. Many immune cells and cytokines have been demonstrated to be involved in the pulmonary vascular lesions in PAH patients, with the activation of downstream signaling pathways related to inflammation. Consistently, this influence has been found to correlate with the progression and clinical outcome of PAH, indicating that immunity and inflammation may have significant potential in PAH therapy. Therefore, we reviewed the pathogenesis of inflammation and immunity in PAH development, focusing on the potential targets and clinical application of anti-inflammatory and immunosuppressive therapy.

Redefining Pulmonary Arterial Hypertension Treatment: Sotatercept's FDA Priority Review

A biologics license application (BLA) for sotatercept, a therapeutic agent targeting activin receptor signaling implicated in pulmonary arterial hypertension (PAH), has been granted priority review status by the FDA. This advancement underscores the critical need for novel pharmacological interventions for this rare and severe condition, potentially transforming the therapeutic landscape of PAH.

Seralutinib in adults with pulmonary arterial hypertension (TORREY): a randomised, double-blind, placebo-controlled phase 2 trial

BACKGROUND

Morbidity and mortality in pulmonary arterial hypertension (PAH) remain high. Activation of platelet-derived growth factor receptor, colony stimulating factor 1 receptor, and mast or stem cell growth factor receptor kinases stimulates inflammatory, proliferative, and fibrotic pathways driving pulmonary vascular remodelling in PAH. Seralutinib, an inhaled kinase inhibitor, targets these pathways. We aimed to evaluate the efficacy and safety of seralutinib in patients with PAH receiving standard background therapy.

METHODS

The TORREY trial was a phase 2, randomised, multicentre, multinational, double-blind, placebo-controlled study. Patients with PAH from 40 hospital and community sites were randomly assigned 1:1 via interactive response technologies to receive seralutinib (60 mg twice daily for 2 weeks, then increased to 90 mg twice daily as tolerated) or placebo by dry powder inhaler twice daily for 24 weeks. Randomisation was stratified by baseline pulmonary vascular resistance (PVR; <800 dyne·s/cm5 and ≥800 dyne·s/cm5). Patients were eligible if classified as WHO Group 1 PH (PAH), WHO Functional Class II or III, with a PVR of 400 dyne·s/cm5 or more, and a 6 min walk distance of between 150 m and 550 m. The primary endpoint was change in PVR from baseline to 24 weeks. Analyses for efficacy endpoints were conducted in randomly assigned patients (intention-to-treat population). Safety analyses included all patients who received the study drug. TORREY was registered with ClinicalTrials.gov (NCT04456998) and EudraCT (2019-002669-37) and is completed.

FINDINGS

From Nov 12, 2020, to April 20, 2022, 151 patients were screened for eligibility, and following exclusions, 86 adults receiving PAH background therapy were randomly assigned to seralutinib (n=44; four male, 40 female) or placebo (n=42; four male, 38 female), and comprised the intention-to-treat population. At baseline, treatment groups were balanced except for a higher representation of WHO Functional Class II patients in the seralutinib group. The least squares mean change from baseline to week 24 in PVR was 21·2 dyne·s/cm5 (95% CI -37·4 to 79·8) for the placebo group and -74·9 dyne·s/cm5 (-139·7 to -10·2) for the seralutinib group. The least squares mean difference between the seralutinib and placebo groups for change in PVR was -96·1 dyne·s/cm5 (95% CI -183·5 to -8·8; p=0·03). The most common treatment-emergent adverse event in both treatment groups was cough: 16 (38%) of 42 patients in the placebo group; 19 (43%) of 44 patients in the seralutinib group.

INTERPRETATION

Treatment with inhaled seralutinib significantly decreased PVR, meeting the primary endpoint of the study among patients receiving background therapy for PAH.

FUNDING

Gossamer Bio.

Prognostic role of haemodynamics at follow-up in patients with pulmonary arterial hypertension: a challenge to current European Society of Cardiology/European Respiratory Society risk tools

Background

Haemodynamic variables like right atrial pressure (RAP), cardiac index (CI), stroke volume index (SVI) and mixed venous oxygen saturation (S vO2 ) predict survival in patients with pulmonary arterial hypertension (PAH). However, there is the need to identify further prognostic haemodynamic parameters as well as to redefine their role in PAH risk stratification compared to current risk tools and non-invasive parameters.

Methods

This cohort study includes treatment-naïve patients assessed at baseline and after first-line PAH therapy with clinical, functional, exercise, laboratory and haemodynamic evaluations. Using a stepwise multivariate Cox regression analysis, independent prognostic haemodynamic parameters were identified and stratified according to cut-offs already defined in the European Society of Cardiology (ESC)/European Respiratory Society (ERS) risk table or defined based on the highest Chi-squared of the log-rank test. Their discriminatory power was tested for all-cause death and a combined end-point of death, hospitalisation and need of treatment escalation.

Results

794 patients with PAH were enrolled. At first follow-up, RAP and pulmonary artery elastance were independently associated with death. Because of high correlations between haemodynamic parameters, different multivariable analyses were done identifying six other variables (pulmonary arterial compliance, cardiac efficiency, pulmonary vascular resistance, S vO2 , CI and SVI). Haemodynamic parameters were of no added prognostic value compared to ESC/ERS risk tools for the all-cause death end-point but they showed additional value to non-invasive parameters for the combined end-point and, when taken alone, had a discriminatory capacity comparable to ESC/ERS risk tools.

Conclusion

Haemodynamics' discriminative ability for clinical worsening is comparable to current ESC/ERS risk tools and is of added value to non-invasive parameters.

Seeing pulmonary hypertension through a paediatric lens: a viewpoint

Pulmonary hypertension (PH) is a life-threating condition associated with abnormally elevated pulmonary pressures and right heart failure. Current epidemiological data indicate that PH aetiologies are different between the adult and paediatric population. The most common forms of PH in adults are PH from left heart disease or chronic lung disease, followed by pulmonary arterial hypertension (PAH) [1]; in paediatric patients, PH is most often associated with developmental lung disorders and congenital heart disease (CHD) [2, 3]. In contrast to adults with PH, wherein patients worsen over time despite therapy, PH in children can improve with growth. For example, in infants with bronchopulmonary dysplasia (BPD) and PH morbidity and mortality are high, but with lung growth and ensuring no ongoing lung injury pulmonary vascular disease can improve as evidenced by discontinuation of vasodilator therapy in almost two-thirds of BPD-PH survivors by age 5 years [3, 4].

Paediatric pulmonary hypertension (PH) offers unique genetic and developmental insights that can help in the discovery of novel mechanisms and targets to treat adult PH https://bit.ly/3TMm6bi

SPECTRA Phase 2b Study: Impact of Sotatercept on Exercise Tolerance and Right Ventricular Function in Pulmonary Arterial Hypertension

BACKGROUND

This study aims to assess the impact of sotatercept on exercise tolerance, exercise capacity, and right ventricular function in pulmonary arterial hypertension.

METHODS

SPECTRA (Sotatercept Phase 2 Exploratory Clinical Trial in PAH) was a phase 2a, single-arm, open-label, multicenter exploratory study that evaluated the effects of sotatercept by invasive cardiopulmonary exercise testing in participants with pulmonary arterial hypertension and World Health Organization functional class III on combination background therapy. The primary end point was the change in peak oxygen uptake from baseline to week 24. Cardiac magnetic resonance imaging was performed to assess right ventricular function.

RESULTS

Among the 21 participants completing 24 weeks of treatment, there was a significant improvement from baseline in peak oxygen uptake, with a mean change of 102.74 mL/min ([95% CIs, 27.72-177.76]; P=0.0097). Sotatercept demonstrated improvements in secondary end points, including resting and peak exercise hemodynamics, and 6-minute walk distance versus baseline measures. Cardiac magnetic resonance imaging showed improvements from baseline at week 24 in right ventricular function.

CONCLUSIONS

The clinical efficacy and safety of sotatercept demonstrated in the SPECTRA study emphasize the potential of this therapy as a new treatment option for patients with pulmonary arterial hypertension. Improvements in right ventricular structure and function underscore the potential for sotatercept as a disease-modifying agent with reverse-remodeling capabilities.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03738150.

ERS International Congress 2023: highlights from the Pulmonary Vascular Diseases Assembly

Pulmonary vascular diseases such as pulmonary embolism and pulmonary hypertension are important and frequently under-recognised conditions. This article provides an overview of key highlights in pulmonary vascular diseases from the European Respiratory Society International Congress 2023. This includes insights into disease modification in pulmonary arterial hypertension and novel therapies such as sotatercept and seralutinib. Exciting developments in our understanding of the mechanisms underpinning pulmonary hypertension associated with interstitial lung disease are also explored. A comprehensive overview of the complex relationship between acute pulmonary embolism and chronic thromboembolic pulmonary hypertension (CTEPH) is provided along with our current understanding of the molecular determinants of CTEPH. The importance of multidisciplinary and holistic care cannot be understated, and this article also addresses advances beyond medication, with a special focus on exercise training and rehabilitation.

Sotatercept and pulmonary arterial hypertension

Pulmonary arterial hypertension is a chronic progressive disease characterized by elevated pulmonary artery pressure, ultimately leading to right heart failure and even death. The primary pathological mechanism of pulmonary arterial hypertension involves pulmonary vascular remodeling, resulting in increased pulmonary vascular resistance. Current targeted therapies for pulmonary arterial hypertension primarily function to dilate the pulmonary arteries, improve hemodynamic parameters, and enhance patients' quality of life. However, these therapies fail to fundamentally reverse pulmonary vascular remodeling or achieve a cure. Sotatercept, the world's first biological agent targeting pulmonary arterial hypertension, restores the balance between pro-proliferative and anti-proliferative signaling pathways, effectively reversing pulmonary vascular remodeling. Multiple clinical trials have demonstrated the efficacy of sotatercept in reducing pulmonary vascular resistance and pulmonary artery pressure, positioning it as one of the most promising targeted therapies for pulmonary arterial hypertension in the future.

Treating Pulmonary Arterial Hypertension With Sotatercept: A Meta-Analysis

Pulmonary arterial hypertension (PAH) results from proliferative remodeling and narrowing of the pulmonary vasculature. Sotatercept is a first-in-class fusion protein that has recently garnered attention for showing improvements in patients with PAH. This meta-analysis of randomized controlled trials (RCTs) assesses the overall efficacy of Sotatercept in treating PAH. PubMed, Google Scholar, and Clinicaltrials.gov were searched using relevant keywords and MeSH terms. Studies were included if RCTs compared Sotatercept with placebo in patients with PAH. Our comprehensive literature search yielded 3,127 results, of which two RCTs with 429 patients were included in this meta-analysis. The patients were on background therapy for PAH. Results of the meta-analysis show that when compared with placebo, Sotatercept improved the six-minute walk distance (mean difference [MD] 34.99; 95% confidence interval [CI] 19.02-50.95; P < 0.0001), the World Health Organization (WHO) functional class (odds ratio [OR] 2.50; 95% CI 1.50-4.15; P = 0.0004), and pulmonary vascular resistance (PVR, MD -253.90; 95% CI -356.05 to -151.75; P < 0.00001). However, reduction in N-terminal pro-B-type natriuretic peptide (NT-proBNP, MD -1563.14; 95% CI -3271.93 to 145.65; P = 0.07) was not statistically significant in the Sotatercept group versus placebo. In conclusion, Sotatercept improves the six-minute walk distance, WHO functional class, and PVR in patients with PAH receiving background therapy. However, the effect on NT-proBNP levels was not statistically significant. More research is needed to assess the clinical relevance of these findings.

Sotatercept for Pulmonary Arterial Hypertension in the Inpatient Setting

Patients with pulmonary arterial hypertension (PAH) who are admitted to the hospital pose a challenge to the multidisciplinary healthcare team due to the complexity of the pathophysiology of their disease state and PAH-specific medication considerations. Pulmonary arterial hypertension is a progressive disease that may lead to death as a result of right ventricular (RV) failure. During acute on chronic RV failure it is critical to decrease the pulmonary vascular resistance with the goal of improving RV function and prognosis; therefore, aggressive PAH-treatment based on disease risk stratification is essential. Pulmonary arterial hypertension treatment for acute on chronic RV failure can be impacted by end-organ damage, hemodynamic instability, drug interactions, and PAH medications dosage and delivery. Sotatercept, a first in class activin signaling inhibitor that works on the bone morphogenetic protein/activin pathway is on track for Food and Drug Administration approval for the treatment of PAH based on results of recent trials in where the medication led to clinical and hemodynamic improvements, even when added to traditional PAH-specific therapies. The purpose of this review is to highlight important considerations when starting or continuing sotatercept in patients admitted to the hospital with PAH.