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.

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.

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.

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.

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.

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.

European Society of Cardiology quality indicators for the care and outcomes of adults with pulmonary arterial hypertension. Developed in collaboration with the Heart Failure Association of the European Society of Cardiology.

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 European Society of Cardiology (ESC) methodology for the development of QIs. This included (i) the identification of key domains of care for the management of PAH, (ii) the proposal of candidate QIs following systematic review of the literature, and (iii) the selection of a set of QIs using a modified Delphi method. The process was undertaken in parallel with the writing of the 2022 ESC/European Respiratory Society (ERS) guidelines for the diagnosis and treatment of pulmonary hypertension and involved the 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.

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.

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.

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.

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.

Contemporary risk scores predict clinical worsening in pulmonary arterial hypertension - An analysis of FREEDOM-EV.

BACKGROUND: Risk scores integrate clinical variables emphasizing symptoms, exercise capacity, and measures of cardiac strain to predict clinical outcome better than any single value in pulmonary arterial hypertension (PAH). Risk scores have demonstrated prognostic utility for outcomes in registries, and recent studies have suggested that they are also therapy-responsive in controlled trials. METHODS: FREEDOM-EV, a global, placebo-controlled, event-driven study, randomized 690 PAH participants 1:1 to oral treprostinil (TRE) or placebo. Clinical assessments were performed every 12 weeks to calculate the non-invasive French risk assessment (FRA), 4-strata COMPERA, REVEAL 2.0, and REVEAL Lite 2; median follow-up was 58 weeks. The Week 12 risk scores were used to predict time to clinical worsening (from Week 12) with Kaplan-Meier product-limit estimates. Log-rank test was used to calculate the statistical difference among risk categories, and mediation analysis tested the hypothesis that improvements in risk score contributed to reduced likelihood for clinical worsening. We assessed the previously proposed "net clinical benefit" (achievement of FRA low-risk status and absence of clinical worsening). RESULTS: Both REVEAL scores, COMPERA, and FRA at Week 12 predicted subsequent clinical worsening better than baseline risk. Mediation analysis demonstrated that Week 12 risk score reduction explained part of TRE's effect on clinical worsening, especially for those with higher baseline risk. TRE assigned participants were more likely to achieve the previously proposed "net clinical benefit" at Weeks 24 and beyond. Few participants who achieved 'net clinical benefit' had subsequent clinical worsening. CONCLUSIONS: Contemporary risk scores were therapy responsive in FREEDOM-EV and early improvements predicted subsequent outcomes. This post hoc analysis suggests that risk scores may be a surrogate for clinical worsening.

INSPIRE: Safety and tolerability of inhaled Yutrepia (treprostinil) in pulmonary arterial hypertension (PAH).

The INSPIRE trial was a Phase 3, open-label, multicenter trial (LTI-301) that enrolled patients with pulmonary arterial hypertension (PAH) ≥ 18 years of age who transitioned to Yutrepia from nebulized treprostinil (Transition) or added Yutrepia to prostacyclin naïve patients on ≤2 nonprostacyclin oral therapies. The objectives of the trial were to evaluate the safety and tolerability of Yutrepia (dry-powder formulation of treprostinil) in patients with PAH. The primary safety measures were the incidence of adverse events (AEs) and serious AEs. Exploratory efficacy measures were also assessed during the trial. Transition patients initiated Yutrepia at a dose comparable to their nebulized treprostinil dose while prostacyclin naïve patients received 26.5-mcg QID; up-titration in 26.5-mcg increments was permitted for both groups. A total of 121 patients were enrolled, of which 29 patients discontinued from the trial, with the most common reason being AEs. Eighty percent of the Transition group and 96% of the prostacyclin naïve group titrated to a dose ≥79.5 mcg QID at Day 360, respectively, with one patient achieving a dose of 212-mcg QID. The most common AEs were cough, headache, upper respiratory tract infection, dyspnea, dizziness, throat irritation, diarrhea, chest discomfort, fatigue, and nasopharyngitis. Most of these events were considered treatment-related though mild to moderate in severity and expected for prostacyclin therapy administered by inhalation. In an evaluation of exploratory efficacy measures, patients remained stable or improved over the 1 year of treatment. Yutrepia was found to be a convenient, safe, and well-tolerated inhaled prostacyclin treatment option for PAH patients.

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.

Application of the REVEAL risk score calculator 2.0 in the CHEST study.

BACKGROUND: Currently there are no risk assessment recommendations for chronic thromboembolic pulmonary hypertension (CTEPH). The Registry to Evaluate Early and Long-Term PAH Disease Management (REVEAL) risk score (RRS), developed for risk assessment in patients with pulmonary arterial hypertension, has previously predicted outcomes in CTEPH. RRS 2.0 was developed to refine the RRS. METHODS: This post hoc analysis of the CHEST study (n = 237), which assessed riociguat in patients with inoperable and persistent/recurrent CTEPH, evaluated RRS 2.0 and its relationship with survival and clinical worsening-free survival (CWFS). RESULTS: At CHEST-1 Week 16, RRS 2.0 significantly improved and more patients moved into the low-risk stratum with riociguat versus placebo; these improvements were maintained at CHEST-2 Week 12. RRS 2.0 at CHEST-1 baseline and Week 16, and change in RRS 2.0 from CHEST-1 baseline to Week 16 were significant predictors of survival and CWFS in CHEST-2. CONCLUSIONS: Our data suggest that RRS 2.0 may have utility in predicting outcomes and monitoring treatment response in patients with inoperable or persistent/recurrent CTEPH.