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.

Genetic regulation and targeted reversal of lysosomal dysfunction and inflammatory sterol metabolism in pulmonary arterial hypertension

Vascular inflammation critically regulates endothelial cell (EC) pathophenotypes, particularly in pulmonary arterial hypertension (PAH). Dysregulation of lysosomal activity and cholesterol metabolism have known inflammatory roles in disease, but their relevance to PAH is unclear. In human pulmonary arterial ECs and in PAH, we found that inflammatory cytokine induction of the nuclear receptor coactivator 7 (NCOA7) both preserved lysosomal acidification and served as a homeostatic brake to constrain EC immunoactivation. Conversely, NCOA7 deficiency promoted lysosomal dysfunction and proinflammatory oxysterol/bile acid generation that, in turn, contributed to EC pathophenotypes. In vivo, mice deficient for Ncoa7 or exposed to the inflammatory bile acid 7α-hydroxy-3-oxo-4-cholestenoic acid (7HOCA) displayed worsened PAH. Emphasizing this mechanism in human PAH, an unbiased, metabolome-wide association study (N=2,756) identified a plasma signature of the same NCOA7-dependent oxysterols/bile acids associated with PAH mortality (P<1.1x10-6). Supporting a genetic predisposition to NCOA7 deficiency, in genome-edited, stem cell-derived ECs, the common variant intronic SNP rs11154337 in NCOA7 regulated NCOA7 expression, lysosomal activity, oxysterol/bile acid production, and EC immunoactivation. Correspondingly, SNP rs11154337 was associated with PAH severity via six-minute walk distance and mortality in discovery (N=93, P=0.0250; HR=0.44, 95% CI [0.21-0.90]) and validation (N=630, P=2x10-4; HR=0.49, 95% CI [0.34-0.71]) cohorts. Finally, utilizing computational modeling of small molecule binding to NCOA7, we predicted and synthesized a novel activator of NCOA7 that prevented EC immunoactivation and reversed indices of rodent PAH. In summary, we have established a genetic and metabolic paradigm and a novel therapeutic agent that links lysosomal biology as well as oxysterol and bile acid processes to EC inflammation and PAH pathobiology. This paradigm carries broad implications for diagnostic and therapeutic development in PAH and in other conditions dependent upon acquired and innate immune regulation of vascular disease.

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

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

CS1, a controlled-release formulation of valproic acid, for the treatment of patients with pulmonary arterial hypertension: Rationale and design of a Phase 2 clinical trial

Although rare, pulmonary arterial hypertension (PAH) is associated with substantial morbidity and a median survival of approximately 7 years, even with treatment. Current medical therapies have a primarily vasodilatory effect and do not modify the underlying pathology of the disease. CS1 is a novel oral, controlled-release formulation of valproic acid, which exhibits a multi-targeted mode of action (pulmonary pressure reduction, reversal of vascular remodeling, anti-inflammatory, anti-fibrotic, and anti-thrombotic) and therefore potential for disease modification and right ventricular modeling in patients with PAH. A Phase 1 study conducted in healthy volunteers indicated favorable safety and tolerability, with no increased risk of bleeding and significant reduction of plasminogen activator inhibitor 1. In an ongoing randomized Phase 2 clinical trial, three doses of open-label CS1 administered for 12 weeks is evaluating the use of multiple outcome measures. The primary endpoint is safety and tolerability, as measured by the occurrence of adverse events. Secondary outcome measures include the use of the CardioMEMS™ HF System, which provides a noninvasive method of monitoring pulmonary artery pressure, as well as cardiac magnetic resonance imaging and echocardiography. Other outcomes include changes in risk stratification (using the REVEAL 2.0 and REVEAL Lite 2 tools), patient reported outcomes, functional capacity, 6-min walk distance, actigraphy, and biomarkers. The pharmacokinetic profile of CS1 will also be evaluated. Overall, the novel design and unique, extensive clinical phenotyping of participants in this trial will provide ample evidence to inform the design of any future Phase 3 studies with CS1.

Do Patients With Low-Risk Pulmonary Arterial Hypertension Really Benefit From Upfront Combination Therapy?: Insight From the AMBITION Trial

BACKGROUND

Based on results of the Ambrisentan and Tadalafil in Patients with Pulmonary Arterial Hypertension (AMBITION) trial, upfront combination therapy is recommended for treatment-naive patients with low-risk pulmonary arterial hypertension (PAH). However, conflicting data exist whether adopting this treatment strategy in this risk group is beneficial or well tolerated.

RESEARCH QUESTION

Do patients with low-risk PAH really benefit from upfront combination therapy?

STUDY DESIGN AND METHODS

Using the data from the original AMBITION trial, patients with PAH were classified as low, intermediate, or high risk using the Registry to Evaluate Early and Long-term PAH Disease Management 2.0 (REVEAL 2.0) score and the Pulmonary Hypertension Outcomes and Risk Assessment (PHORA) tool. The primary end point was time to clinical worsening (including death, hospitalization for PAH worsening, and disease progression) censored at 1- and 3-year post-enrollment. Side effects that led to withdrawal of treatment were also considered.

RESULTS

Patients with low-risk PAH categorized by REVEAL 2.0 and PHORA did not see a statistically significant benefit of upfront combination therapy vs monotherapy for time to clinical worsening at 1 and 3 years' post-enrollment using Cox proportional analysis (3-year hazard ratio of 0.40 [95% CI, 0.15-1.06; P = .07] and 0.55 [95% CI, 0.26-1.18; P = .12] for REVEAL 2.0 and PHORA, respectively) or considering time to clinical worsening or side effects (3-year hazard ratio of 0.75 [95% CI, 0.39-1.47; P = .4] and 0.87 [95% CI, 0.49-1.54; P = .63] for REVEAL 2.0 and PHORA). Patients with low-risk PAH on upfront combination therapy experienced a higher but not significant incidence of side effects using REVEAL 2.0 and PHORA. In contrast, patients at intermediate or high risk saw a statistically significant benefit of upfront combination therapy considering each of the end points regardless of side effects.

INTERPRETATION

This analysis suggests that perhaps some patients with low-risk PAH should be further stratified using other modalities prior to committing to upfront combination therapy, especially when the occurrence of side effects is considered. Further prospective data are needed to validate this hypothesis prior to changes in current guideline directed therapy are contemplated.

Real-world evidence to advance knowledge in pulmonary hypertension: Status, challenges, and opportunities. A consensus statement from the Pulmonary Vascular Research Institute's Innovative Drug Development Initiative's Real-world Evidence Working Group

This manuscript on real-world evidence (RWE) in pulmonary hypertension (PH) incorporates the broad experience of members of the Pulmonary Vascular Research Institute's Innovative Drug Development Initiative Real-World Evidence Working Group. We aim to strengthen the research community's understanding of RWE in PH to facilitate clinical research advances and ultimately improve patient care. Herein, we review real-world data (RWD) sources, discuss challenges and opportunities when using RWD sources to study PH populations, and identify resources needed to support the generation of meaningful RWE for the global PH community.

Treatment effects of pulmonary artery denervation for pulmonary arterial hypertension stratified by REVEAL risk score: Results from PADN-CFDA trial

BACKGROUND

The differential treatment effect of pulmonary artery denervation (PADN) in pulmonary arterial hypertension (PAH) patients with different risk burdens remains unclear. This study aimed to determine the effectiveness of PADN in low vs intermediate-high-risk PAH patients.

METHODS

In total, 128 patients with treatment naive PAH included in the PADN-CFDA trial were categorized into low-risk and intermediate-high-risk patients. The primary endpoint was the between-group difference in the change in 6-min walk distance (6 MWD) from baseline to 6 months.

RESULTS

In the intermediate-high-risk group, those treated with PADN and PDE-5i had a greater improvement in 6 MWD from baseline to 6 months as compared to those treated with sham plus PDE-5i. From baseline to 6 months, pulmonary vascular resistance (PVR) was reduced by -6.1 ± 0.6 and -2.0 ± 0.7 Wood units following PADN plus PDE-5i and sham plus PDE-5i, respectively, along with the significant reduction of NT-proBNP in the intermediate-high-risk group. However, there were no significant differences in 6 MWD, PVR, and NT-proBNP between the PADN plus PDE-5i and sham plus PDE-5i groups among low-risk patients. Moreover, the right ventricular function was equally improved by PADN treatment across the low-, intermediate-, and high-risk groups. Clinical worsening was less with PADN plus PDE-5i treatment during the 6-month follow-up.

CONCLUSIONS

In patients with pulmonary arterial hypertension, pulmonary artery denervation plus PDE-5i improved exercise capacity, NT-proBNP, hemodynamic, and clinical outcomes during the 6-month follow-up among intermediate-high risk patients.

European Society of Cardiology Quality Indicators for the care and outcomes of adults with pulmonary arterial hypertension

AIMS

To develop a suite of quality indicators (QIs) for the evaluation of the care and outcomes for adults with pulmonary arterial hypertension (PAH).

METHODS AND RESULTS

We followed the ESC methodology for the development of QIs. This included the 1) identification of key domains of care for the management of PAH, 2) proposal of candidate QIs following systematic review of the literature, and 3) selection of a set of QIs using a modified-Delphi method. The process was undertaken in parallel with the writing of the 2022 European Society of Cardiology (ESC) / European Respiratory Society (ERS) guidelines for the diagnosis and treatment of pulmonary hypertension and involved Task Force chairs, experts in PAH, Heart Failure Association (HFA) members and patient representatives. We identified five domains of care for patients with PAH; structural framework, diagnosis and risk stratification, initial treatment, follow up, and outcomes. In total, 23 main and one secondary QIs for PAH were selected.

CONCLUSION

This document presents the ESC QIs for PAH, describes their development process and offers scientific rationale for their selection. The indicators may be used to quantify and improve adherence to guideline-recommended clinical practice and improve patient outcomes. This article is protected by copyright. All rights reserved.

Pulmonary artery compliance in different forms of pulmonary hypertension

OBJECTIVE

Pulmonary artery compliance (PAC), estimated as stroke volume (SV) divided by pulmonary artery pulse pressure (PP), may be a predictor of survival in pulmonary arterial hypertension (PAH). Resistance-compliance (RC) time, the product of PAC and pulmonary vascular resistance, is reported to be a physiological constant. We investigated if differences in PAC and RC time exist between pulmonary hypertension (PH) subgroups and examined whether PAC is an independent predictor of transplant-free survival in PAH.

METHODS

This was a retrospective analysis of adult PAH (n=532) and chronic thromboembolic PH (CTEPH, n=84) patients enrolled in the US Pulmonary Hypertension Association Registry from 2015 to 2019. PAC and RC time were compared between PH subgroups (connective tissue disease-PAH (CTD-PAH), idiopathic/heritable-PAH (i/h-PAH), drug/toxin-PAH (d/t-PAH)). Cox proportional hazards models were constructed for transplant-free survival, adjusting for REVEAL 2.0 risk score.

RESULTS

There were no differences in estimated PAC between PAH subgroups, nor between PAH and CTEPH. RC time was shorter in CTEPH compared with PAH (median 0.55 (IQR 0.45-0.64) vs 0.62 (0.52-0.73) s, p<0.0001). RC time was shortest in CTD-PAH when compared with i/h-PAH and d/t-PAH ((0.59±0.18) vs (0.65±0.20) vs (0.73±0.25) s, p=0.0001). PAC was associated with transplant-free survival (HR 0.72, 95% CI 0.55 to 0.94, p=0.02) but was not an independent predictor of outcome after adjustment for REVEAL 2.0 score.

CONCLUSION

PAC was similar between PH groups and was not an independent predictor of transplant-free survival in PAH. RC time was different between PH subgroups, challenging RC time constancy.

TRIAL REGISTRATION NUMBER

NCT04071327.

Prognostic role of pulmonary hemodynamics before transcatheter aortic valve replacement among patients with severe aortic stenosis

BACKGROUND

Pulmonary hypertension (PH) frequently co-exists in patients with severe aortic stenosis (AS). In this study, we sought to identify the implications of invasive pulmonary hemodynamics on major adverse cardiac events (MACE), biventricular function and NYHA functional class after transcatheter aortic valve replacement (TAVR).

METHODS

Invasive hemodynamics via right heart catheterization (RHC) were performed pre-TAVR. Patients were stratified per mean PA pressure (mPAP), diastolic pulmonary gradient (DPG) and pulmonary vascular resistance (PVR), and followed at 1-month and 1-year intervals up to 6 years. MACE outcomes included cardiovascular death and heart failure hospitalizations post-TAVR.

RESULTS

Among 215 patients, Kaplan-Meir estimates demonstrated an increased 1-year risk of MACE from 8% among those without pre-TAVR PH to 27% among patients with pre-existing PH. Specifically, the MACE risk was 32% among PH patients with PVR ≥ 3WU (p = .04) and 53% among PH patients with DPG ≥ 7 mm Hg (p < .01). On univariate Cox regression, RV stroke work index (RVSWI) (HR,1.02; p = .02), and pulmonary hemodynamic index (PHI) (HR,1.27; p = .047) were identified as additional predictors of MACE post-TAVR. On multivariable Cox regression analysis, SvO2 (HR, 0.95; p = .01) and PVR (HR, 1.2; p = .04) were demonstrated as predictive of MACE post-TAVR. A significant improvement in LVEF (2-Factor ANOVA, p < .01) and RV fractional area change (RVFAC%) (p < .01) was noted as assessed at baseline, 1-month and 1-year follow up post-TAVR. There was a significant interaction between pre-TAVR PH status and time post procedure with respect to NYHA functional class (p = .03), that is, the manner and degree of change in NYHA class over time depended on pre-TAVR PH status.

CONCLUSIONS

Defining invasive pulmonary hemodynamics, such as mPAP, PVR, and DPG among patients with severe AS undergoing TAVR has significant prognostic implications. Routine risk stratification by utilizing invasive hemodynamics can better identify patients who will have functional improvement and improved outcomes post-TAVR.

Riociguat and the right ventricle in pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension

Pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) are progressive diseases that can lead to right heart failure and death. Right ventricular dysfunction, hypertrophy and maladaptive remodelling are consequences of increased right ventricular (RV) afterload in PAH and CTEPH and are indicative of long-term outcomes. Because RV failure is the main cause of morbidity and mortality in PAH and CTEPH, successful treatments should lead to improvements in RV parameters. Riociguat is a soluble guanylate cyclase stimulator approved for the treatment of PAH and inoperable or persistent/recurrent CTEPH after pulmonary endarterectomy. This review examines the current evidence showing the effect of riociguat on the right ventricle, with particular focus on remodelling, function and structural parameters in preclinical models and patients with PAH or CTEPH.

Plasma Cell-Free DNA Predicts Survival and Maps Specific Sources of Injury in Pulmonary Arterial Hypertension

BACKGROUND

Cell-free DNA (cfDNA) is a noninvasive marker of cellular injury. Its significance in pulmonary arterial hypertension (PAH) is unknown.

METHODS

Plasma cfDNA was measured in 2 PAH cohorts (A, n=48; B, n=161) and controls (n=48). Data were collected for REVEAL 2.0 (Registry to Evaluate Early and Long-Term PAH Disease Management) scores and outcome determinations. Patients were divided into the following REVEAL risk groups: low (≤6), medium (7-8), and high (≥9). Total cfDNA concentrations were compared among controls and PAH risk groups by 1-way analysis of variance. Log-rank tests compared survival between cfDNA tertiles and REVEAL risk groups. Areas under the receiver operating characteristic curve were estimated from logistic regression models. A sample subset from cohort B (n=96) and controls (n=16) underwent bisulfite sequencing followed by a deconvolution algorithm to map cell-specific cfDNA methylation patterns, with concentrations compared using t tests.

RESULTS

In cohort A, median (interquartile range) age was 62 years (47-71), with 75% female, and median (interquartile range) REVEAL 2.0 was 6 (4-9). In cohort B, median (interquartile range) age was 59 years (49-71), with 69% female, and median (interquartile range) REVEAL 2.0 was 7 (6-9). In both cohorts, cfDNA concentrations differed among patients with PAH of varying REVEAL risk and controls (analysis of variance P≤0.002) and were greater in the high-risk compared with the low-risk category (P≤0.002). In cohort B, death or lung transplant occurred in 14 of 54, 23 of 53, and 35 of 54 patients in the lowest, middle, and highest cfDNA tertiles, respectively. cfDNA levels stratified as tertiles (log-rank: P=0.0001) and REVEAL risk groups (log-rank: P<0.0001) each predicted transplant-free survival. The addition of cfDNA to REVEAL improved discrimination (area under the receiver operating characteristic curve, 0.72-0.78; P=0.02). Compared with controls, methylation analysis in patients with PAH revealed increased cfDNA originating from erythrocyte progenitors, neutrophils, monocytes, adipocytes, natural killer cells, vascular endothelium, and cardiac myocytes (Bonferroni adjusted P<0.05). cfDNA concentrations derived from erythrocyte progenitor cells, cardiac myocytes, and vascular endothelium were greater in patients with PAH with high-risk versus low-risk REVEAL scores (P≤0.02).

CONCLUSIONS

Circulating cfDNA is elevated in patients with PAH, correlates with disease severity, and predicts worse survival. Results from cfDNA methylation analyses in patients with PAH are consistent with prevailing paradigms of disease pathogenesis.

Two polymorphic gene loci associated with treprostinil dose in pulmonary arterial hypertension

OBJECTIVE

Prostacyclin infusion for pulmonary arterial hypertension (PAH) is an effective therapy with varied dosing requirements and clinical response. The major aim of this study was to determine new biologically-based predictors of prostacyclin treatment response heterogeneity.

METHODS

Ninety-eight patients with hemodynamically defined PAH at two academic medical centers volunteered for registry studies. A stable dose of treprostinil was the quantitative phenotype for the genome-wide association study (GWAS). Candidate genes with the largest effect sizes and strongest statistical associations were further characterized with in silico and in-vitro assays to confirm mechanistic hypotheses. The clinical significance of these candidate predictors was assessed for mechanistically consistent physiologic effects in an independent cohort of patients.

RESULTS

GWAS identified three loci for association with P < 10-6. All three loci had clinically significant effect sizes. Specific single-nucleotide polymorphisms (SNPs) at two of the loci: rs11078738 in phosphoribosylformylglycinamidine synthase and rs10023113 in CAMK2D encoded sequence changes with clear predicted consequences. Production of the primary mediator of prostacyclin-induced vasodilation, cyclic AMP, was reduced in human cell lines by the missense variant rs11078738 (p.L621P). Located in the promoter of CAMK2D, the allele of rs10023113 associated with a higher treprostinil dose has higher ventricular transcription of CAMK2δ. At initial diagnostic catheterization in a separate cohort of patients, the same allele of rs10023113 was associated with elevated right mean atrial and ventricular diastolic pressures.

CONCLUSIONS

The quantitative phenotype of stable treprostinil dose identified two gene loci associated with pharmacodynamic response and right ventricular function in PAH worth further investigation.

Aggressive Afterload Lowering to Improve the Right Ventricle: A New Target for Medical Therapy in Pulmonary Arterial Hypertension?

Despite numerous therapeutic advances in pulmonary arterial hypertension, patients continue to suffer high morbidity and mortality, particularly considering a median age of 50 years. This article explores whether early, robust reduction of right ventricular afterload would facilitate substantial improvement in right ventricular function and thus whether afterload reduction should be a treatment goal for pulmonary arterial hypertension. The earliest clinical studies of prostanoid treatment in pulmonary arterial hypertension demonstrated an important link between lowering mean pulmonary arterial pressure (or pulmonary vascular resistance) and improved survival. Subsequent studies of oral monotherapy or sequential combination therapy demonstrated smaller reductions in mean pulmonary arterial pressure and pulmonary vascular resistance. More recently, retrospective reports of initial aggressive prostanoid treatment or initial combination oral and parenteral therapy have shown marked afterload reduction along with significant improvements in right ventricular function. Some data suggest that reaching threshold levels for pressure or resistance (components of right ventricular afterload) may be key to interrupting the self-perpetuating injury of pulmonary vascular disease in pulmonary arterial hypertension and could translate into improved long-term clinical outcomes. Based on these clues, the authors postulate that improved clinical outcomes might be achieved by targeting significant afterload reduction with initial oral combination therapy and early parenteral prostanoids.

Safety and efficacy of RT234 vardenafil inhalation powder on exercise parameters in pulmonary arterial hypertension: phase II, dose-escalation study design

BACKGROUND

Pulmonary arterial hypertension (PAH) is a progressive disease characterized by high mean pulmonary arterial pressure (≥ 20 mmHg) and remodeling of the vascular arteries. Approved therapies improve symptoms and delay clinical worsening in the long term, but they do not relieve acute exertional symptoms. RT234, a drug/device combination (Respira Therapeutics, Palo Alto, CA, USA) that delivers the phosphodiesterase 5 inhibitor vardenafil to the lungs via inhalation, has been shown to reduce pulmonary vascular resistance in patients with PAH. This study aims to evaluate whether RT234 can increase oxygen capacity during cardiopulmonary exercise testing (CPET) in patients with PAH.

METHODS

This prospective, multi-center, open-label, two-cohort, dose-escalation, phase IIb trial in patients with PAH will evaluate the safety and efficacy of RT234 in improving exercise parameters. The trial began in September 2020 and is expected to be completed by early 2024. Patients eligible for enrollment will have a right heart catheterization-confirmed diagnosis of PAH, a 6-minute walking distance of ≥ 150 m, a minute ventilation/carbon dioxide production slope of ≥ 36, and will be on up to three stable oral and/or inhaled (not parenteral) PAH-specific background therapies. The estimated sample size is 86 patients, who will be divided into two dose cohorts. Cohort 1 will receive 0.5 mg RT234, and cohort 2 will receive 1.0 mg RT234. Each cohort will contain two subgroups based on the number of PAH background medications (up to two vs three). The trial will assess patients' changes from baseline in peak oxygen consumption (VO₂) during CPET 30 minutes after a single dose of 0.5 mg or 1.0 mg RT234, the change in the 6-minute walking distance, and the pharmacokinetics and safety profile of single doses of RT234.

CONCLUSION

This is the first trial involving an as-needed medication for PAH. The trial will provide insights into the safety and efficacy of as-needed RT234 in treating the acute symptoms of PAH during exercise and will inform the design of further trials.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov identifier NCT04266197.

TORREY, a Phase 2 study to evaluate the efficacy and safety of inhaled seralutinib for the treatment of pulmonary arterial hypertension

Aberrant kinase signaling that involves platelet-derived growth factor receptor (PDGFR) α/β, colony stimulating factor 1 receptor (CSF1R), and stem cell factor receptor (c-KIT) pathways may be responsible for vascular remodeling in pulmonary arterial hypertension. Targeting these specific pathways may potentially reverse the pathological inflammation, cellular proliferation, and fibrosis associated with pulmonary arterial hypertension progression. Seralutinib (formerly known as GB002) is a novel, potent, clinical stage inhibitor of PDGFRα/β, CSF1R, and c-KIT delivered via inhalation that is being developed for patients with pulmonary arterial hypertension. Here, we report on an ongoing Phase 2 randomized, double-blind, placebo-controlled trial (NCT04456998) evaluating the efficacy and safety of seralutinib in subjects with World Health Organization Group 1 Pulmonary Hypertension who are classified as Functional Class II or III. A total of 80 subjects will be enrolled and randomized to receive either study drug or placebo for 24 weeks followed by an optional 72-week open-label extension study. The primary endpoint is the change from baseline to Week 24 in pulmonary vascular resistance by right heart catheterization. The secondary endpoint is the change in distance from baseline to Week 24 achieved in the 6-min walk test. A computerized tomography sub-study will examine the effect of seralutinib on pulmonary vascular remodelling. A separate heart rate monitoring sub-study will examine the effect of seralutinib on cardiac effort during the 6-min walk test.

Change in REVEAL Lite 2 risk score predicts outcomes in patients with pulmonary arterial hypertension in the PATENT study

BACKGROUND

Risk assessment is essential in pulmonary arterial hypertension (PAH) management. We investigated the effect of riociguat on REVEAL Lite 2 score, an abridged version of the REVEAL risk score, and its association with long-term outcomes in PATENT.

METHODS

PATENT-1 was a randomized, double-blind study of riociguat vs placebo in patients with PAH. In the PATENT-2 open-label extension, all patients received riociguat up to 2.5 mg three times daily (n = 396). REVEAL Lite 2 scores were calculated at baseline, PATENT-1 Week 12, and PATENT-2 Week 12, with patients stratified as low- (1-5), intermediate- (6-7), or high-risk (≥8). Kaplan-Meier and Cox proportional hazards analyses assessed association of riociguat with survival and clinical worsening-free survival (CWFS).

RESULTS

REVEAL Lite 2 score improved with riociguat 2.5 mg at PATENT-1 Week 12 (least-squares mean difference vs placebo: -0.8; p = 0.0004). More patients receiving riociguat 2.5 mg stabilized or improved risk stratum at PATENT-1 Week 12 vs placebo (p = 0.0005) and achieved low-risk status. REVEAL Lite 2 score at baseline and PATENT-1 Week 12 were associated with survival and CWFS (all p < 0.0001), as was change in score from baseline to Week 12 (p = 0.0002 and p < 0.0001, respectively). Survival and CWFS differed between risk strata at baseline (p < 0.0001) and PATENT-1 Week 12 (p < 0.0001).

CONCLUSIONS

This analysis confirms the risk-reduction benefits of riociguat in patients with PAH and further contributes to the validation of REVEAL Lite 2 in facilitating PAH risk assessment.

Changes in cMRI parameters following a switch to riociguat from phosphodiesterase type 5 inhibitors (PDE5i) in patients with pulmonary arterial hypertension: a REPLACE substudy

Background

The REPLACE study investigated the effect of switching to riociguat (RIO) in patients with pulmonary arterial hypertension receiving PDE5i but still at intermediate risk. The centrally adjudicated composite primary endpoint was clinical improvement in the absence of clinical worsening, where clinical improvement was defined as meeting at least two of the following criteria: 6-minute walk distance (6MWD), increase by ≥10% or ≥30 m from baseline (BL) to Wk 24; World Health Organization functional class (WHO FC) I or II at Wk 24; or N-terminal prohormone of brain natriuretic peptide reduction of ≥30% from BL to Wk 24. Twice as many patients switching to RIO (45/111, 41%) met the primary endpoint compared with those remaining on PDE5i (23/113, 20%); odds ratio (OR): 2.78 (95% confidence interval [CI] 1.53–5.06); p=0.0007.

Purpose

Assess changes in right and left ventricular (RV; LV) function using cardiac magnetic resonance imaging (cMRI) in a subgroup of patients participating in REPLACE.

Methods

REPLACE was a randomised, open-label, 24-week, Phase 4 study (NCT02891850). Patients in WHO FC III, with 6MWD 165–440 m, were randomised to switch to RIO 2.5 mg–max tid or remain on PDE5i. Background endothelin receptor antagonist therapy was permitted in both arms.

cMRI was performed on a subset of patients from the full analysis set as an exploratory substudy. The following parameters were measured at BL and Wk 24: RV and LV end-diastolic and end-systolic volumes (RVEDV; RVESV; LVEDV; LVESV), RV stroke volume and stroke volume index (RVSV; RVSVI), LV stroke volume (LVSV), RV ejection fraction (RVEF), and pericardial effusion.

Results

Twenty-seven patients participated in the cMRI substudy. This comprised 11/111 (10%) patients in the RIO arm (mean [standard deviation {SD}] 40.0 [12.4] years), and 16/113 (14%) patients (mean 44.5 [17.6] years) in the PDE5i arm. Like the main population, the treatment response in the cMRI subpopulation favoured RIO versus PDE5i (OR: 6.11 [95% CI 0.90–41.60]). From BL to Wk 24, RVEDV and RVESV decreased in the RIO treatment arm but increased in the PDE5i treatment arm (Table 1). Similar, but less pronounced, changes were observed for the left ventricle (LVESV, LVEDV). RVSV and RVEF levels were close to normal at BL and did not increase in either arm at Wk 24 (Table 1). Pericardial effusion, which was present in 5 patients in each group at BL, decreased in 1 patient in the RIO arm and no patients in the PDE5i arm.

Conclusions

Decreases in RVEDV and RVESV suggest improvements in cardiac function in the RIO arm compared with the PDE5i arm. Values for RVEF and RVSVI were close to normal at BL and did not change at Wk 24. Improvements in cMRI parameters were in line with the clinical improvement observed in patients switching to RIO in the overall population.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): The REPLACE study was co-funded by Bayer AG (Berlin, Germany) and Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc. (Kenilworth, NJ, USA)

Development and validation of a claims-based model to identify patients at risk of chronic thromboembolic pulmonary hypertension following acute pulmonary embolism

OBJECTIVE

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare disease that often follows pulmonary embolism (PE). Screening for CTEPH is challenging, often delaying diagnosis and worsening prognosis. Predictive risk models for CTEPH could help identify at-risk patients, but existing models require multiple clinical inputs. We developed and validated a predictive risk model for CTEPH using health insurance claims that can be used by payers/quality-of-care organizations to screen patients post-PE.

METHODS

Adult patients newly diagnosed with acute PE (index date) were identified from the Optum De-identified Clinformatics Extended DataMart (January 2007-March 2018; development set) and IBM MarketScan (January 2008-June 2019; validation set) databases. Predictors were identified 12 months before or on the index PE. Risk of "likely CTEPH" was assessed post-PE based on CTEPH-related diagnoses and procedures since the CTEPH diagnosis code (ICD-10-CM: I27.24) was not available until 1 October 2017. Stepwise variable selection was used to build the model using the development set; model validation was subsequently conducted using the validation set.

RESULTS

The development set included 93,428 patients, of whom 11,878 (12.7%) developed likely CTEPH. Older age (odds ratios [OR] = 1.16-1.49), female (OR = 1.09), unprovoked PE (i.e. without thrombotic factors; OR = 1.14), hypertension (OR = 1.07), osteoarthritis (OR = 1.08), diabetes (OR = 1.07), chronic obstructive pulmonary disease (OR = 1.11), obesity (OR = 1.21) were associated with higher odds of likely CTEPH, and oral anticoagulants with lower odds (OR= 0.50, all p < .01). C-statistic was 0.77 in the development and validation sets.

CONCLUSION

A claims-based risk model reliably predicted the risk of CTEPH post-PE and could be used to identify high-risk patients who may benefit from focused monitoring.

Effect of riociguat on right ventricular function in patients with pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension

BACKGROUND

In the Phase III PATENT-1 (NCT00810693) and CHEST-1 (NCT00855465) studies, riociguat demonstrated efficacy vs placebo in patients with pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH). Clinical effects were maintained at 2 years in the long-term extension studies PATENT-2 (NCT00863681) and CHEST-2 (NCT00910429).

METHODS

This post hoc analysis of hemodynamic data from PATENT-1 and CHEST-1 assessed whether riociguat improved right ventricular (RV) function parameters including stroke volume index (SVI), stroke volume, RV work index, and cardiac efficiency. REVEAL Risk Score (RRS) was calculated for patients stratified by SVI and right atrial pressure (RAP) at baseline and follow-up. The association between RV function parameters and SVI and RAP stratification with long-term outcomes was assessed.

RESULTS

In PATENT-1 (n = 341) and CHEST-1 (n = 238), riociguat improved RV function parameters vs placebo (p < 0.05). At follow-up, there were significant differences in RRS between patients with favorable and unfavorable SVI and RAP, irrespective of treatment arm (p < 0.0001). Multiple RV function parameters at baseline and follow-up were associated with survival and clinical worsening-free survival (CWFS) in PATENT-2 (n = 396; p < 0.05) and CHEST-2 (n = 237). In PATENT-2, favorable SVI and RAP at follow-up only was associated with survival and CWFS (p < 0.05), while in CHEST-2, favorable SVI and RAP at baseline and follow-up were associated with survival and CWFS (p < 0.05).

CONCLUSION

This post hoc analysis of PATENT and CHEST suggests that riociguat improves RV function in patients with PAH and CTEPH.

Impact of thoracotomy approach on right ventricular failure and length of stay in left ventricular assist device implants: an intermacs registry analysis

INTRODUCTION

Traditionally, implantation of Left Ventricular Assist Devices (LVADs) is performed via median sternotomy. Recently, less invasive thoracotomy approaches are growing in popularity as they involve less surgical trauma, potentially less bleeding, and may preserve right ventricular function. We hypothesized implantation of LVADs via thoracotomy has less perioperative right ventricular failure (RVF) and shorter postoperative length of stay (LOS).

METHODS

Continuous flow LVAD implants from Intermacs between February 6, 2014 - December 31, 2018 were identified. Patients implanted via thoracotomy were propensity matched in a 1:1 ratio with patients implanted via sternotomy. Outcomes were compared between sternotomy and thoracotomy approach and by device type (axial, centrifugal-flow with hybrid levitation (CF-HL), centrifugal-flow with full magnetic levitation devices (CF-FML)). The primary outcome was time to first moderate or severe RVF. Secondary outcomes included survival and LOS.

RESULTS

Overall 978 thoracotomy patients were matched with 978 sternotomy patients. Over the study period, 242 thoracotomy patients and 219 sternotomy patients developed RVF with no significant difference in time to first moderate to severe RVF by surgical approach overall (p = 0.27) or within CF-HL (p = 0.36) or CF-FML devices (p = 0.25). Survival did not differ by implant technique (150 deaths in thoracotomy group, 154 deaths in sternotomy group; p = 0.58). However, sternotomy approach was associated with a significantly shorter LOS (17 Vs 18 days, p = 0.009).

CONCLUSION

As compared to sternotomy, implantation of continuous flow LVADs via thoracotomy approach does not reduce moderate to severe RVF or improve survival but does reduce post-operative LOS. Device type did not influence outcomes and most centers did a small volume of thoracotomy implants.

Results From the United States Chronic Thromboembolic Pulmonary Hypertension Registry: Enrollment Characteristics and 1-Year Follow-up

Background

The United States Chronic Thromboembolic Pulmonary Hypertension Registry (US-CTEPH-R) was designed to characterize the demographic characteristics, evaluation, clinical course, and outcomes of surgical and nonsurgical therapies for patients with chronic thromboembolic pulmonary hypertension.

Research Question

What are the differences in baseline characteristics and 1-year outcomes between operated and nonoperated subjects?

Study Design and Methods

This study describes a multicenter, prospective, longitudinal, observational registry of patients newly diagnosed (< 6 months) with CTEPH. Inclusion criteria required a mean pulmonary artery pressure ≥ 25 mm Hg documented by right heart catheterization and radiologic confirmation of CTEPH. Between 2015 and 2018, a total of 750 patients were enrolled and followed up biannually until 2019.

Results

Most patients with CTEPH (87.9%) reported a history of acute pulmonary embolism. CTEPH diagnosis delays were frequent (median, 10 months), and most patients reported World Health Organization functional class 3 status at enrollment with a median mean pulmonary artery pressure of 44 mm Hg. The registry cohort was subdivided into Operable patients undergoing pulmonary thromboendarterectomy (PTE) surgery (n = 566), Operable patients who did not undergo surgery (n = 88), and those who were Inoperable (n = 96). Inoperable patients were older than Operated patients; less likely to be obese; have a DVT history, non-type O blood group, or thrombophilia; and more likely to have COPD or a history of cancer. PTE resulted in a median pulmonary vascular resistance decline from 6.9 to 2.6 Wood units (P < .001) with a 3.9% in-hospital mortality. At 1-year follow-up, Operated patients were less likely treated with oxygen, diuretics, or pulmonary hypertension-targeted therapy compared with Inoperable patients. A larger percentage of Operated patients were World Health Organization functional class 1 or 2 at 1 year (82.9%) compared with the Inoperable (48.2%) and Operable/No Surgery (56%) groups (P < .001).

Interpretation

Differences exist in the clinical characteristics between patients who exhibited operable CTEPH and those who were inoperable, with the most favorable 1-year outcomes in those who underwent PTE surgery.

Clinical Trial Registration

ClinicalTrials.gov; No.: NCT02429284; URL: www.clinicaltrials.gov.

The United States Chronic Thromboembolic Pulmonary Hypertension Registry: Protocol for a Prospective, Longitudinal Study

Background

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare sequela of acute pulmonary embolism that is treatable when recognized. Awareness of this disease has increased with recent advancements in therapeutic options, but delays in diagnosis remain common, and diagnostic and treatment guidelines are often not followed. Data gathered from international registries have improved our understanding of CTEPH, but these data may not be applicable to the US population owing to differences in demographics and medical practice patterns.

Objective

The US CTEPH Registry (US-CTEPH-R) was developed to provide essential information to better understand the demographics, risk factors, evaluation, and treatment of CTEPH in the United States, as well as the short- and long-term outcomes of surgical and nonsurgical therapies in the modern treatment era.

Methods

Thirty sites throughout the United States enrolled 750 subjects in this prospective, longitudinal, observational registry of patients newly diagnosed with CTEPH. Enrollment criteria included a mean pulmonary artery pressure ≥25 mmHg by right heart catheterization and radiologic confirmation of CTEPH by a multidisciplinary adjudication committee. Following enrollment, subjects were followed biannually until the conclusion of the study. Quality of life surveys were administered at enrollment and biannually, and all other testing was at the discretion of the treating clinician. Details regarding surgical therapy, balloon pulmonary angioplasty, and medical therapy were collected at enrollment and at follow-up, as well as information related to health care utilization and survival.

Results

Data from this registry will improve understanding of the demographics, risk factors, and treatment patterns of patients with CTEPH, and the longitudinal impact of therapies on quality of life, health care utilization, and survival.

Conclusions

This manuscript details the methodology and design of the first large, prospective, longitudinal registry of patients with CTEPH in the United States.

Trial Registration

ClinicalTrials.gov NCT02429284; https://www.clinicaltrials.gov/ct2/show/NCT02429284

International Registered Report Identifier (IRRID)

DERR1-10.2196/25397

Enrichment Benefits of Risk Algorithms for Pulmonary Arterial Hypertension Clinical Trials

Rationale: Event-driven primary endpoints are increasingly used in pulmonary arterial hypertension clinical trials, substantially increasing required sample sizes and trial lengths. The U.S. Food and Drug Administration advocates the use of prognostic enrichment of clinical trials by preselecting a patient population with increased likelihood of experiencing the trial's primary endpoint.Objectives: This study compares validated clinical scales of risk (Comparative, Prospective Registry of Newly Initiated Therapies for Pulmonary Hypertension, the French score, and Registry to Evaluate Early and Long-Term Pulmonary Arterial Hypertension Disease Management [REVEAL] 2.0) to identify patients who are likely to experience a clinical worsening event for trial enrichment.Methods: Baseline data from three pulmonary arterial hypertension clinical trials (AMBITION [a Study of First-Line Ambrisentan and Tadalafil Combination Therapy in Subjects with Pulmonary Arterial Hypertension], SERAPHIN [Study of Macitentan on Morbidity and Mortality in Patients with Symptomatic Pulmonary Arterial Hypertension], and GRIPHON [Selexipag in Pulmonary Arterial Hypertension]) were pooled and standardized. Receiver operating curves were used to measure each algorithm's performance in predicting clinical worsening within the pooled placebo cohort. Power simulations were conducted to determine sample size and treatment time reductions for multiple enrichment strategies. A cost analysis was performed to illustrate potential financial savings by applying enrichment to GRIPHON.Measurements and Main Results: All risk algorithms were compared using area under the receiver operating curve and substantially outperformed prediction per New York Heart Association Functional Class. The REVEAL 2.0's risk grouping provided the greatest time and sample size savings in AMBITION and GRIPHON for all enrichment strategies but lacked appropriate inputs (i.e., N-terminal-proB-type natriuretic peptide) to perform as well in SERAPHIN. Cost analysis applied to GRIPHON demonstrated the greatest financial benefit by enrolling patients with a REVEAL score ≥8.Conclusions: This preliminary study demonstrates the feasibility of risk algorithms for pulmonary arterial hypertension trial enrichment and a need for further investigation.

Switching to riociguat versus maintenance therapy with phosphodiesterase-5 inhibitors in patients with pulmonary arterial hypertension (REPLACE): a multicentre, open-label, randomised controlled trial

BACKGROUND

Riociguat and phosphodiesterase-5 inhibitors (PDE5i), approved for the treatment of pulmonary arterial hypertension (PAH), act on the same pathway via different mechanisms. Riociguat might be an alternative option for patients with PAH who do not respond sufficiently to treatment with PDE5i, but comparisons of the potential benefits of riociguat and PDE5i in these patients are needed. The aim of this trial was to assess the effects of switching to riociguat from PDE5i therapy versus continued PDE5i therapy in patients with PAH at intermediate risk of 1-year mortality.

METHODS

Riociguat rEplacing PDE5i therapy evaLuated Against Continued PDE5i thErapy (REPLACE) was an open-label, randomised controlled trial in 81 hospital-based pulmonary hypertension centres in 22 countries. The study enrolled patients aged 18-75 years with symptomatic PAH at intermediate risk of 1-year mortality (based on the European Society for Cardiology-European Respiratory Society guideline thresholds for WHO functional class and 6-min walk distance [6MWD]) who were receiving treatment with a PDE5i with or without an endothelin receptor antagonist for at least 6 weeks before randomisation. Patients were excluded if they had been previously treated with riociguat, had used prostacyclin analogues or prostacyclin receptor agonists within 30 days before randomisation, had clinically significant restrictive or obstructive parenchymal lung disease, or had left heart disease. Patients were randomly assigned (1:1) to remain on PDE5i treatment (oral sildenafil [≥60 mg per day] or oral tadalafil [20-40 mg per day]; the PDE5i group) or to switch to oral riociguat (up to 2·5 mg three times per day; the riociguat group), using an interactive voice and web response system, stratified by cause of PAH. The primary endpoint was clinical improvement by week 24, defined as an absence of clinical worsening and prespecified improvements in at least two of three variables (6MWD, WHO functional class, and N-terminal prohormone of brain natriuretic peptide), analysed using last observation carried forward in all randomly assigned patients with observed values at baseline and week 24 who received at least one dose of study medication (the full analysis set). Secondary endpoints included clinical worsening events. The trial has been completed and is registered with ClinicalTrials.gov, NCT02891850.

FINDINGS

Between Jan 11, 2017, and July 31, 2019, 293 patients were screened, of which 226 patients were randomly assigned to the riociguat group (n=111) or to the PDE5i group (n=115). 211 patients completed the study and 14 patients discontinued (seven in each group). One patient assigned to the PDE5i group did not receive treatment, so 225 patients were included in the safety analysis, and one further patient in the PDE5i group had missing components of the composite primary endpoint at baseline, so 224 patients were included in the full analysis set. The primary endpoint was met by 45 (41%) of 111 patients in the riociguat group and 23 (20%) of 113 patients in the PDE5i group; odds ratio [OR] 2·78 (95% CI 1·53-5·06; p=0·0007). Clinical worsening events occurred in one (1%) of 111 patients in the riociguat group (hospitalisation due to worsening PAH) and 10 (9%) of 114 patients in the PDE5i group (hospitalisation due to worsening PAH [n=9]; disease progression [n=1]; OR 0·10 [0·01-0·73]; p=0·0047). The most frequently occurring adverse events were hypotension (15 [14%]), headache (14 [13%]), and dyspepsia (10 [9%]) in the riociguat group, and headache (eight [7%]), cough (seven [6%]), and upper respiratory tract infection (seven [6%]) in the PDE5i group. Serious adverse events were reported in eight (7%) of 111 patients in the riociguat group and 19 (17%) of 114 patients in the PDE5i group. During the study, four patients died in the PDE5i group, one of them during the safety follow-up period.

INTERPRETATION

Switching to riociguat from PDE5i treatment, both of which act via the nitric oxide-soluble guanylate cyclase-cyclic guanosine monophosphate pathway, could be a strategic option for treatment escalation in patients with PAH at intermediate risk of 1-year mortality.

FUNDING

Bayer AG, Merck Sharp & Dohme.

Application of the REVEAL risk score calculator 2.0 in the PATENT study

BACKGROUND

Regular risk assessment is recommended in pulmonary arterial hypertension (PAH) management to improve patient outcomes. The REVEAL risk score (RRS) predicts survival in patients with PAH, including those from the PATENT study, which assessed riociguat, a soluble guanylate cyclase stimulator approved for PAH treatment. An updated version, RRS 2.0, has been developed to further refine risk prediction.

METHODS

This post hoc analysis of PATENT-1 and its open-label extension PATENT-2 (n = 396) assessed RRS 2.0 score and risk stratum and their association with survival and clinical worsening-free survival (CWFS).

RESULTS

At PATENT-1 Week 12, riociguat improved RRS 2.0 versus placebo (least-squares mean difference versus placebo: -1.0 [95% confidence interval - 1.4 to -0.6; p < 0.0001]) and more patients improved risk stratum with riociguat (57%) versus placebo (42%). These improvements were maintained at PATENT-2 Week 12. RRS 2.0 score and risk strata at PATENT-1 baseline and Week 12 were significantly associated with survival and CWFS in PATENT-2 (p < 0.0001); change in RRS 2.0 score from PATENT-1 baseline to Week 12 was also significantly associated with outcomes.

CONCLUSIONS

These data suggest that RRS 2.0 has clinical utility in predicting long-term outcomes and monitoring treatment response in patients with PAH.

Risk assessment in patients with pulmonary arterial hypertension in the era of COVID 19 pandemic and the telehealth revolution: State of the art review

Patients affected by pulmonary arterial hypertension (PAH) benefit from intensive, continuous clinical monitoring to guide escalation of treatments that carry the potential to improve survival and quality of life. During the coronavirus disease 2019 pandemic, the need for physical distancing has fueled the expeditious expansion of various telehealth modalities, which may apply in a unique manner to individuals with PAH. Performance of objective risk assessments in patients with PAH remotely via telemedical visits and other telehealth mechanisms is unprecedented and not yet rigorously validated. The uniquely high risk for rapid deterioration in patients with PAH demands a high degree of sensitivity to detect changes in functional assessments. In this review, several telehealth modalities for potential utilization in risk assessment and treatment titration in patients with PAH are explored, yet additional study is needed for their validation with the pre-pandemic care paradigm.

Development and Validation of an Abridged Version of the REVEAL 2.0 Risk Score Calculator, REVEAL Lite 2, for Use in Patients With Pulmonary Arterial Hypertension

BACKGROUND

Achievement of low-risk status is a treatment goal in pulmonary arterial hypertension (PAH). Risk assessment often is performed using multiparameter tools, such as the Registry to Evaluate Early and Long-Term PAH Disease Management (REVEAL) risk calculator. Risk calculators that assess fewer variables without compromising validity may expedite risk assessment in the routine clinic setting. We describe the development and validation of REVEAL Lite 2, an abridged version of REVEAL 2.0.

RESEARCH QUESTION

Can a simplified version of the REVEAL 2.0 risk assessment calculator for patients with PAH be developed and validated?

STUDY DESIGN AND METHODS

REVEAL Lite 2 includes six noninvasive variables-functional class (FC), vital signs (systolic BP [SBP] and heart rate), 6-min walk distance (6MWD), brain natriuretic peptide (BNP)/N-terminal prohormone of brain natriuretic peptide (NT-proBNP), and renal insufficiency (by estimated glomerular filtration rate [eGFR])-and was validated in a series of analyses (Kaplan-Meier, concordance index, Cox proportional hazard model, and multivariate analysis).

RESULTS

REVEAL Lite 2 approximates REVEAL 2.0 at discriminating low, intermediate, and high risk for 1-year mortality in patients in the REVEAL registry. The model indicated that the most highly predictive REVEAL Lite 2 parameter was BNP/NT-proBNP, followed by 6MWD and FC. Even if multiple, less predictive variables (heart rate, SBP, eGFR) were missing, REVEAL Lite 2 still discriminated among risk groups.

INTERPRETATION

REVEAL Lite 2, an abridged version of REVEAL 2.0, provides a simplified method of risk assessment that can be implemented routinely in daily clinical practice. REVEAL Lite 2 is a robust tool that provides discrimination among patients at low, intermediate, and high risk of 1-year mortality.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT00370214; URL: www.clinicaltrials.gov.

Safety and efficacy of transitioning from the combination of bosentan and sildenafil to alternative therapy in patients with pulmonary arterial hypertension

The combination of bosentan and sildenafil is commonly used to treat patients with pulmonary arterial hypertension (PAH); however, there is evidence of a significant drug interaction between these two medications. We sought to evaluate the safety and efficacy of transitioning patients with PAH from the combination of bosentan and sildenafil to alternative therapy. A retrospective database review was performed on 16 patients with PAH who were treated with the combination of bosentan and sildenafil and transitioned to alternative treatment at our center. Invasive and non-invasive patient parameters were collected at baseline and after transition. 56.3% of patients were in World Health Organization functional class (WHO FC) III and a majority of patients (68.7%) were on background prostacyclin therapy. The most common reason for transition was concern for a drug interaction in seven patients (43.8%). The most common transition was bosentan to macitentan in eight patients (50%). Fifteen patients (93.8%) tolerated the transition after a median follow-up of 6.5 months with minor adverse events occurring in four patients (25%). In 11 patients, 6-min walk distance (6MWD) was unchanged comparing baseline to post transition measurements with a median change of +8 m (range: −50 to + 70; P = 0.39). Nine patients (81.8%) had stable (within 15% margin) or significant improvement (increase by ≥15%) in 6MWD after transition. All patients demonstrated stable or improved WHO FC after transition. There were no significant changes after transition in hemodynamics, N-terminal pro-brain natriuretic peptide (NT-proBNP) values, or Registry to Evaluate Early and Long-Term PAH Disease Management (REVEAL) risk scores. In our study, transitioning patients from bosentan and sildenafil to alternative therapy was safe and resulted in clinical stability.

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.

Pulmonary vasodilators: beyond the bounds of pulmonary arterial hypertension therapy in COVID-19

Pulmonary arterial hypertension (PAH) and novel coronavirus (SARS-CoV-2) disease COVID-19 are characterized by extensive endothelial dysfunction and inflammation leading to vascular remodeling and severe microthrombi and microvascular obliterative disease. It is hypothesized that those patients with underlying lung disease, like PAH, represent a high-risk cohort in this pandemic. However, reports of COVID-19 in this cohort of patient have been scaring and an observational survey showed that the disease was relatively well tolerated. We postulate that specific PAH vasodilator may offer some protection and/or advantage in the case of concomitant COVID-19. Here we review the literature describing mechanisms of action for each of the broad categories of PAH therapy, and offer potential hypothesis about why this therapy may impact outcomes in COVID-19.

Data on clinical and economic burden associated with pulmonary arterial hypertension related hospitalizations in the United States

A comprehensive description of the contemporary trends in pulmonary arterial hypertension (PAH) related hospitalizations, associated inpatient outcomes and predictors of worse outcomes were reported in our paper recently published in the International Journal of Cardiology [1]. Our observational analysis utilized ten year of national inpatient sample from January 1st 2007 through December 31st 2016. This Data in Brief companion paper aims to report the specific statistical highlights of the entire ten-year PAH cohort including demographics, hospital characteristics, regional variation, prevalence of comorbidities, and multivariable regression analysis used to examine the factors associated with increased inpatient mortality and prolonged length of stay. Additionally, we report trends in the cost (the actual amount of money reimbursed to the hospitals) of PAH related hospitalizations over the past ten years.

Residence at moderately high altitude and its relationship with WHO Group 1 pulmonary arterial hypertension symptom severity and clinical characteristics: the Pulmonary Hypertension Association Registry

BACKGROUND

WHO Group 1 pulmonary arterial hypertension is a progressive and potentially fatal disease. Individuals living at higher altitude are exposed to lower barometric pressure and hypobaric hypoxemia. This may result in pulmonary vasoconstriction and contribute to disease progression. We sought to examine the relationship between living at moderately high altitude and pulmonary arterial hypertension characteristics.

METHODS

Forty-two US centers participating in the Pulmonary Hypertension Association Registry enrolled patients who met the definition of WHO Group 1 pulmonary arterial hypertension. We utilized baseline data and patient questionnaire responses. Patients were divided into two groups: moderately high altitude residence (home ≥4000 ft) and low altitude residence (home <4000 ft) based on zip-code. Clinical characteristics, hemodynamic data, patient demographics, and patient reported quality of life metrics were compared.

RESULTS

Controlling for potential confounders (age, sex at birth, body mass index, supplemental oxygen use, race, 100-day cigarette use, alcohol use, and pulmonary arterial hypertension medication use), subjects residing at moderately high altitude had a 6-min walk distance 32 m greater than those at low altitude, despite having a pulmonary vascular resistance that was 2.2 Wood units higher. Additionally, those residing at moderately high altitude had 3.7 times greater odds of using supplemental oxygen.

CONCLUSION

Patients with pulmonary arterial hypertension who live at moderately high altitude have a higher pulmonary vascular resistance and are more likely to need supplemental oxygen. Despite these findings, moderately high altitude Pulmonary Hypertension Association Registry patients have better functional tolerance as measured by 6-min walk distance. It is possible that a "high-altitude phenotype" of pulmonary arterial hypertension may exist. These findings warrant further study.

A Case Report of a Patient With Pulmonary Arterial Hypertension Transitioned From Inhaled Iloprost to Selexipag

Pulmonary arterial hypertension (PAH) is a progressive disease characterized by elevated pulmonary vascular resistance that can lead to right ventricular failure and death. The use of medications that affect the prostacyclin pathway is an important treatment strategy in PAH. Inhaled iloprost is a prostacyclin analogue, and selexipag is an oral, non-prostanoid, prostacyclin IP receptor agonist. Data are limited on transitioning patients from inhaled iloprost to selexipag. In this case report, we describe the successful transition of a 57-year-old female with heritable PAH from inhaled iloprost to selexipag over 8 weeks in an out-patient setting. After initiation of selexipag, the patient's inhaled iloprost dose was gradually reduced and eventually discontinued. The patient tolerated the transition well with stable symptoms, 6-minute walk distance, and pulmonary hemodynamics. Additional studies are needed to better define the comparative efficacy and safety of inhaled iloprost and selexipag.

Risk stratification in pulmonary arterial hypertension using Bayesian analysis

BACKGROUND

Current risk stratification tools in pulmonary arterial hypertension (PAH) are limited in their discriminatory abilities, partly due to the assumption that prognostic clinical variables have an independent and linear relationship to clinical outcomes. We sought to demonstrate the utility of Bayesian network-based machine learning in enhancing the predictive ability of an existing state-of-the-art risk stratification tool, REVEAL 2.0.

METHODS

We derived a tree-augmented naïve Bayes model (titled PHORA) to predict 1-year survival in PAH patients included in the REVEAL registry, using the same variables and cut-points found in REVEAL 2.0. PHORA models were validated internally (within the REVEAL registry) and externally (in the COMPERA and PHSANZ registries). Patients were classified as low-, intermediate- and high-risk (<5%, 5-20% and >10% 12-month mortality, respectively) based on the 2015 European Society of Cardiology/European Respiratory Society guidelines.

RESULTS

PHORA had an area under the curve (AUC) of 0.80 for predicting 1-year survival, which was an improvement over REVEAL 2.0 (AUC 0.76). When validated in the COMPERA and PHSANZ registries, PHORA demonstrated an AUC of 0.74 and 0.80, respectively. 1-year survival rates predicted by PHORA were greater for patients with lower risk scores and poorer for those with higher risk scores (p<0.001), with excellent separation between low-, intermediate- and high-risk groups in all three registries.

CONCLUSION

Our Bayesian network-derived risk prediction model, PHORA, demonstrated an improvement in discrimination over existing models. This is reflective of the ability of Bayesian network-based models to account for the interrelationships between clinical variables on outcome, and tolerance to missing data elements when calculating predictions.

United States Pulmonary Hypertension Scientific Registry: Baseline Characteristics

BACKGROUND

The treatment, genotyping, and phenotyping of patients with World Health Organization Group 1 pulmonary arterial hypertension (PAH) have evolved dramatically in the last decade.

RESEARCH QUESTION

The United States Pulmonary Hypertension Scientific Registry was established as the first US PAH patient registry to investigate genetic information, reproductive histories, and environmental exposure data in a contemporary patient population.

STUDY DESIGN AND METHODS

Investigators at 15 US centers enrolled consecutively screened adults diagnosed with Group 1 PAH who had enrolled in the National Biological Sample and Data Repository for PAH (PAH Biobank) within 5 years of a cardiac catheterization demonstrating qualifying hemodynamic criteria. Exposure and reproductive histories were collected by using a structured interview and questionnaire. The biobank provided genetic data.

RESULTS

Between 2015 and 2018, a total of 499 of 979 eligible patients with clinical diagnoses of idiopathic PAH (IPAH) or familial PAH (n = 240 [48%]), associated PAH (APAH; n = 256 [51%]), or pulmonary venoocclusive disease/pulmonary capillary hemangiomatosis (n = 3 [1%]) enrolled. The mean age was 55.8 years, average BMI was 29.2 kg/m², and 79% were women. Mean duration between symptom onset and diagnostic catheterization was 1.9 years. Sixty-six percent of patients were treated with more than one PAH medication at enrollment. Past use of prescription weight loss drugs (16%), recreational drugs (27%), and oral contraceptive pills (77%) was common. Women often reported miscarriage (37%), although PAH was rarely diagnosed within 6 months of pregnancy (1.9%). Results of genetic testing identified pathogenic or suspected pathogenic variants in 13% of patients, reclassifying 18% of IPAH patients and 5% of APAH patients to heritable PAH.

INTERPRETATION

Patients with Group 1 PAH remain predominately middle-aged women diagnosed with IPAH or APAH. Delays in diagnosis of PAH persist. Treatment with combinations of PAH-targeted medications is more common than in the past. Women often report pregnancy complications, as well as exposure to anorexigens, oral contraceptives, and/or recreational drugs. Results of genetic tests frequently identify unsuspected heritable PAH.

Association of Ambulatory Hemodynamic Monitoring of Heart Failure With Clinical Outcomes in a Concurrent Matched Cohort Analysis

Importance

In a randomized clinical trial, heart failure (HF) hospitalizations were lower in patients managed with guidance from an implantable pulmonary artery pressure sensor compared with usual care. It remains unclear if ambulatory monitoring could also improve long-term clinical outcomes in real-world practice.

Objective

To determine the association between ambulatory hemodynamic monitoring and rates of HF hospitalization at 12 months in clinical practice.

Design, Setting, and Participants

This matched cohort study of Medicare beneficiaries used claims data collected between June 1, 2014, and March 31, 2016. Medicare patients who received implants of a pulmonary artery pressure sensor were identified from the 100% Medicare claims database. Each patient who received an implant was matched to a control patient by demographic features, history of HF hospitalization, and number of all-cause hospitalizations. Propensity scoring based on comorbidities (arrhythmia, hypertension, diabetes, pulmonary disease, and renal disease) was used for additional matching. Data analysis was completed from July 2017 through January 2019.

Exposures

Implantable pulmonary artery pressure monitoring system.

Main Outcomes and Measures

The rates of HF hospitalization were compared using the Andersen-Gill method. Days lost owing to events were compared using a nonparametric bootstrap method.

Results

The study cohort consisted of 1087 patients who received an implantable pulmonary artery pressure sensors and 1087 matched control patients. The treatment and control cohorts were well matched by age (mean [SD], 72.7 [10.2] years vs 72.9 [10.1] years) and sex (381 of 1087 female patients [35.1%] in each group), medical history, comorbidities, and timing of preimplant HF hospitalization. At 12 months postimplant, 616 HF hospitalizations occurred in the treatment cohort compared with 784 HF hospitalizations in the control cohort. The rate of HF hospitalization was lower in the treatment cohort at 12 months postimplant (hazard ratio [HR], 0.76 [95% CI, 0.65-0.89]; P < .001). The percentage of days lost to HF hospitalizations or death were lower in the treatment group (HR, 0.73 [95% CI, 0.64-0.84]; P < .001) and the percentage of days lost owing to all-cause hospitalization or death were also lower (HR, 0.77 [95% CI, 0.68-0.88]; P < .001).

Conclusions and Relevance

Patients with HF who were implanted with a pulmonary artery pressure sensor had lower rates of HF hospitalization than matched controls and spent more time alive out of hospital. Ambulatory hemodynamic monitoring may improve outcomes in patients with chronic HF.

Genetic Admixture and Survival in Diverse Populations with Pulmonary Arterial Hypertension

Rationale: Limited information is available on racial/ethnic differences in pulmonary arterial hypertension (PAH).Objectives: Determine effects of race/ethnicity and ancestry on mortality and disease outcomes in diverse patients with PAH.Methods: Patients with Group 1 PAH were included from two national registries with genome-wide data and two local cohorts, and further incorporated in a global meta-analysis. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for transplant-free, all-cause mortality in Hispanic patients with non-Hispanic white (NHW) patients as the reference group. Odds ratios (ORs) for inpatient-specific mortality in patients with PAH were also calculated for race/ethnic groups from an additional National Inpatient Sample dataset not included in the meta-analysis.Measurements and Main Results: After covariate adjustment, self-reported Hispanic patients (n = 290) exhibited significantly reduced mortality versus NHW patients (n = 1,970) after global meta-analysis (HR, 0.60 [95% CI, 0.41-0.87]; P = 0.008). Although not significant, increasing Native American genetic ancestry appeared to account for part of the observed mortality benefit (HR, 0.48 [95% CI, 0.23-1.01]; P = 0.053) in the two national registries. Finally, in the National Inpatient Sample, an inpatient mortality benefit was also observed for Hispanic patients (n = 1,524) versus NHW patients (n = 8,829; OR, 0.65 [95% CI, 0.50-0.84]; P = 0.001). An inpatient mortality benefit was observed for Native American patients (n = 185; OR, 0.38 [95% CI, 0.15-0.93]; P = 0.034).Conclusions: This study demonstrates a reproducible survival benefit for Hispanic patients with Group 1 PAH in multiple clinical settings. Our results implicate contributions of genetic ancestry to differential survival in PAH.

Age-related differences in hemodynamics and functional status in pulmonary arterial hypertension: Baseline results from the Pulmonary Hypertension Association Registry

BACKGROUND

The age of patients with pulmonary arterial hypertension (PAH) has increased, with registries now reporting mean ages of 50 to 65 years old. Limited data exist on age-related differences in hemodynamic and functional assessments in PAH.

METHODS

Adults with PAH in the Pulmonary Hypertension Association Registry were divided into 3 groups (18-50, 51-65, and >65 years old). Analysis of variance and chi-square testing were used to assess for baseline differences. Linear regression was used to examine the association of age with continuous hemodynamic and functional variables.

RESULTS

A total of 769 patients with mean age of 56 ± 16 years were included. Older patients had more connective tissue disease-associated PAH and less drug-associated PAH. In linear regression models, each year of increased age was associated with shorter 6-minute walk distance (-3.37 meters; 95% CI, -3.97 to -2.76), lower mean pulmonary arterial pressure (-0.21 mm Hg; 95% CI, -0.27 to -0.15), and lower pulmonary vascular resistance (-0.06 Wood units; 95% CI, -0.09 to -0.04). Pulmonary arterial compliance, cardiac index, right ventricular stroke work index, and percent predicted 6-minute walk distance were unrelated to age; resistance-compliance time was negatively related to age (-3 milliseconds per year; 95% CI, -4 to -2).

CONCLUSIONS

Relative to their pulmonary vascular resistance, older patients have lower pulmonary artery compliance and worse right ventricular performance. Based on these findings, we suspect that age influences right ventricular loading conditions and the response of the right ventricle to increased afterload.