Incident and prevalent cohorts with pulmonary arterial hypertension: insight from SERAPHIN

The direct and indirect health care costs associated with pulmonary arterial hypertension among commercially insured patients in the United States

BACKGROUND: Pulmonary arterial hypertension (PAH) is a rare, progressive, and fatal disease associated with considerable overall clinical and economic burden. Although the direct health care costs of PAH have been well described, there are few data regarding indirect costs and productivity loss associated with PAH. Patient data were assessed until the earliest of death, end of full-time employment, end of continuous enrollment, or end of study period. OBJECTIVES: To update data on the direct burden and address the knowledge gap regarding the indirect burden associated with PAH. METHODS: This is a retrospective case-control study with prevalent and incident patients with PAH aged 18-64 years identified from the MarketScan Commercial and Health and Productivity management datasets during the identification period (January 1, 2016, to November 30, 2018). Patients were required to have continuous enrollment for 12 months or longer from the baseline period and 1 month or longer from the follow-up (post-index) period. Among patients with PAH (cases), the first observed PAH diagnosis claim date during the identification period was the index date. Patients without PAH (controls) were selected and assigned a random index date during the same period. Controls were matched 1:1 by age, sex, and region to prevalent and incident PAH cases. Per patient per month (PPPM), all-cause health care resource utilization, costs, and short-term disability (STD) were examined for cases and controls during the follow-up period. Multivariable analysis was performed using the generalized linear model to determine the adjusted direct and indirect health care utilization and costs. RESULTS: A total of 1,293 prevalent and 455 incident patients with PAH were identified. During the follow-up period, prevalent patients with PAH had significantly higher total mean all-cause health care costs ($9,915 vs $359, P < 0.0001) and inpatient length of stay (0.63 vs 0.02 days, P < 0.0001) PPPM as compared with controls. Prevalent patients with PAH had significantly longer STD (6.0 vs 1.5 days, P < 0.0001) and higher STD-related costs ($1,226 vs $277, P < 0.0001) PPPM as compared with controls. Incident patients with PAH had significantly higher total mean all-cause health care costs ($9,353 vs $336, P < 0.0001) and inpatient length of stay (0.92 vs 0.01 days, P < 0.0001) PPPM as compared with controls. Incident patients with PAH also had longer STD (8.1 vs 1.5 days, P < 0.0001) and higher STD-related costs ($1,706 vs $263, P < 0.0001), as compared with controls. CONCLUSIONS: This study showed that incident and prevalent patients with PAH had significantly higher direct and indirect health care resource utilization and costs as well as productivity loss compared with patients without PAH. DISCLOSURES: Ms Ogbomo and Mr Mallampati were paid employees of STATinMED Research at the time of study completion; STATinMED Research is a paid consultant to Janssen Scientific Affairs, LLC. Drs Tsang and Panjabi are employees of Janssen Scientific Affairs LLC, a subsidiary of Johnson and Johnson, the study sponsor.

Riociguat in the Treatment of Pulmonary Arterial Hypertension in Mexico

Pulmonary arterial hypertension (PAH) is a severe clinical condition that significantly affects patients' quality of life and survival. Since the emergence of prostanoids 45 years ago, different drugs acting on vasoconstriction/vasodilation mechanisms have been developed for the treatment of PAH. Current evidence shows that better results occur when combined therapy is initiated up-front with periodic and systematized evaluations for escalation and switching. Among these strategies, riociguat has a relevant role, supported by the results of several clinical studies. This document issues recommendations by a panel of experts who analysed and discussed the indications and limitations for riociguat in PAH in different institutions of the Mexican health system.

Relationship Between Time From Diagnosis and Morbidity/Mortality in Pulmonary Arterial Hypertension: Results From the Phase III GRIPHON Study

BACKGROUND

Early initiation of pulmonary arterial hypertension (PAH) therapies is associated with improved long-term outcomes, yet data on the early use of prostacyclin pathway agents are limited. In these post hoc analyses of the Prostacyclin (PGI₂) Receptor Agonist In Pulmonary Arterial Hypertension (GRIPHON) study, the largest randomized controlled trial for PAH to date, the prognostic value of time from diagnosis and its impact on treatment response were examined.

RESEARCH QUESTION

How does time from diagnosis impact morbidity/mortality events and response to selexipag treatment in patients with PAH?

STUDY DESIGN AND METHODS

The GRIPHON study randomly assigned 1,156 patients with PAH to selexipag or placebo treatment. Patients were categorized post hoc into a time from diagnosis of ≤ 6 months and > 6 months at randomization. Hazard ratios (selexipag vs placebo) were calculated for the primary end point of morbidity/mortality by time from diagnosis using Cox proportional hazard models.

RESULTS

Time from diagnosis was ≤ 6 months in 34.9% and > 6 months in 65.1% of patients. Time from diagnosis was prognostic of morbidity/mortality, with newly diagnosed patients having a poorer long-term outcome than patients diagnosed for longer. Compared with placebo, selexipag reduced the risk of morbidity/mortality in patients with a time from diagnosis of ≤ 6 months and > 6 months, with a more pronounced effect in newly diagnosed patients (hazard ratio, 0.45 [95% CI, 0.33-0.63] and 0.74 [95% CI, 0.57-0.96], respectively; P = .0219 for interaction).

INTERPRETATION

In the GRIPHON study, newly diagnosed PAH patients had a worse prognosis than patients with a longer time from diagnosis. The benefit of selexipag treatment on disease progression was more pronounced in patients treated earlier than in patients treated later.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT01106014; URL: www.clinicaltrials.gov.

Changes in REVEAL risk score in patients with pulmonary arterial hypertension treated with macitentan in clinical practice: results from the PRACMA study

Background

Macitentan is a dual endothelin receptor antagonist indicated for the long-term treatment of pulmonary arterial hypertension (PAH). We evaluated the change over time in REVEAL risk score in incident and prevalent patients receiving macitentan for the first time.

Methods

Retrospective, observational study including adult patients with idiopathic/heritable PAH or PAH associated with connective tissue disorders or congenital heart disease treated with macitentan for ≥6-month follow-up in Spain. The REVEAL risk score and risk strata were computed at the start of macitentan and after ≥6-month in patients with ≥7 out of 12 valid REVEAL components.

Results

Overall, 81 patients (57 for the REVEAL score) were analysed, 77.8% women. The mean age was 57.2 years and 50.6% of patients had idiopathic/heritable PAH. Prevalent patients were 59.3 and 40.7% were incident. Main therapies for PAH included macitentan monotherapy (42.0%) and macitentan in combination with phosphodiesterase type 5 inhibitor (44.4%). With a median time of macitentan treatment of 10.5 months, the mean REVEAL score was 8.7 points at baseline and was 7.2 points after ≥6-month follow-up. The mean change (95% CI) in REVEAL risk score was − 1.4 (− 2.0, − 0.9) points (p < 0.0001), being − 1.8 (− 3.0, − 0.7) points (p = 0.0040) and − 1.2 (− 1.8, − 0.5) points (p = 0.0010), in incident and prevalent patients, respectively. The reduction was also significant by risk stratum (36.8% of patients in the high-very high risk strata at baseline versus 14.0% after ≥6-month, p < 0.05) and therapy group. The REVEAL components that significantly improved were WHO functional class (FC) (63.9% FC III at macitentan initiation and 23.6% after ≥6-month, p < 0.0001), 6-min walk test (mean change: 41.8 m, p < 0.01), brain natriuretic peptide (BNP) or N-terminal proBNP (NT-proBNP) (mean change of − 157.6 pg/mL and − 530.0 pg/mL, respectively, p < 0.05 both), and pulmonary vascular resistance (PVR) (mean change: − 3.4 WU, p < 0.01).

Conclusions

In this study, treatment with macitentan improved the REVEAL risk strata and score in both incident and prevalent PAH patients, and in all patients regardless of the therapy strategy. Macitentan significantly improved some of REVEAL components including WHO FC, BNP/NT-proBNP, PVR, and 6-min walk test after at least 6-month follow-up.

Macitentan in the treatment of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is an uncommon but lethal and progressive disease in which prostacyclin, nitric oxide and endothelin-1 pathways are disturbed and contribute to the pathophysiology of this disease. Endothelin receptor antagonists are a class of drugs that have been approved as PAH therapy. Macitentan is a lipophilic, tissue specific, dual receptor antagonist with a higher potency than bosentan and a reduced risk of hepatic injury. Macitentan has shown a reduction in morbidity and mortality due to PAH at long-term follow-up and improvements in hemodynamics, exercise capacity and functional class at the short term. Its main adverse events are nasopharyngitis, bronchitis and an increased risk of anemia. We review the clinical data of macitentan and its use in PAH.

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

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

Identification of a pulmonary arterial hypertension (PAH) patient cohort and study of its burden of illness in Programme de Médicalisation des Systèmes d'information (PMSI)

OBJECTIVES

Define a French PAH cohort using an evidence-based algorithm and describe its burden of disease in terms of healthcare resource use and costs.

METHODS

A retrospective database analysis was performed using the French national hospital discharge database (PMSI-MCO, 2012-2016). The main criteria used to define the PAH patient cohort were the PH ICD-10 codes (I27.0 or I27.2), a visit to an expert referral centre, a right heart catheterisation procedure and/or a prescription of a PAH specific drug. Hospital visits were split based on the length of stay. 0-day length of stay visits were labelled outpatient visits while all others were labelled inpatient visits.

RESULTS

A cohort of 2173 patients diagnosed with PAH was defined. These patients had 26,944 hospital visits over the study period. Approximately 63% of patients were female and mean age at index date was 58 years old. Inpatient visits represented 52% of total hospital events with an average between 2.2 and 2.3 inpatient visits per year per patient. The average number of outpatient visits per year increased from 1.4 to 2.5 (2012 to 2016). The average cost per patient in 2016 for inpatient visits was equal to €10,256 while outpatient visits cost was equal to €1899. The 20% of patients associated with the highest costs accounted for approximately 60% of total costs in each year.

CONCLUSIONS

There is a high hospital economic burden of PAH in France. The high level of resource use and costs is mainly attributable to inpatient visits and has remained stable throughout the time period studied.

Treatment of pulmonary arterial hypertension with the dual endothelin receptor antagonist macitentan: clinical evidence and experience

Macitentan (10 mg once daily orally), a dual endothelin receptor antagonist (ERA) developed by modifying the structure of bosentan to increase the efficacity and safety, is approved for the treatment of pulmonary arterial hypertension (PAH). The pivotal SERAPHIN trial, (a landmark trial in the history of PAH trials because of the large number of included patients, the long-term follow up and the first trial with morbidity/mortality as the primary endpoint) showed a reduction of the risk of a morbidity or mortality event by 45% over the treatment time compared with placebo. The positive effect on the primary endpoint was observed whether or not the patient was already on PAH therapy. There has been no direct comparison between macitentan and other ERAs, which were approved based on improved exercise capacity, but preclinical and clinical data suggest better pharmacological and safety profiles. Further analyses of the SERAPHIN trial investigated the predictive value of different indices and events on long-term outcome and mortality. The efficacy in children, the long-term effects and safety of macitentan and its place in combination therapy compared with other ERAs are still under investigation. This review presents the preclinical evidence of superiority of macitentan compared with other ERAs, and the available clinical trial data. The place of macitentan in the therapeutic algorithm for PAH treatment, post-marketing experience and future perspectives are discussed.

2018 TSOC guideline focused update on diagnosis and treatment of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is characterized as a progressive and sustained increase in pulmonary vascular resistance, which may induce right ventricular failure. In 2014, the Working Group on Pulmonary Hypertension of the Taiwan Society of Cardiology (TSOC) conducted a review of data and developed a guideline for the management of PAH.⁴ In recent years, several advancements in diagnosis and treatment of PAH has occurred. Therefore, the Working Group on Pulmonary Hypertension of TSOC decided to come up with a focused update that addresses clinically important advances in PAH diagnosis and treatment. This 2018 focused update deals with: (1) the role of echocardiography in PAH; (2) new diagnostic algorithm for the evaluation of PAH; (3) comprehensive prognostic evaluation and risk assessment; (4) treatment goals and follow-up strategy; (5) updated PAH targeted therapy; (6) combination therapy and goal-orientated therapy; (7) updated treatment for PAH associated with congenital heart disease; (8) updated treatment for PAH associated with connective tissue disease; and (9) updated treatment for chronic thromboembolic pulmonary hypertension.

Pulmonary arterial hypertension in systemic sclerosis: Diagnosis and treatment according to the European Society of Cardiology and European Respiratory Society 2015 guidelines

Scleroderma (systemic sclerosis) is an autoimmune connective tissue disease which presents endothelial dysfunction and fibroblast dysregulation, resulting in vascular and fibrotic disorders. Pulmonary hypertension is frequent in patients with systemic sclerosis: the natural evolution of the disease can induce the development of different forms of pulmonary hypertension, representing one of the main causes of death. Among the different forms of pulmonary hypertension in systemic sclerosis, pulmonary arterial hypertension is the most frequent one (rate of occurrence is estimated between 7% and 12%). This pulmonary vascular complication should be treated with a combination of drugs that is able to counteract endothelial dysfunction, antagonizing the endothelin-1 system and replacing prostaglandin I2 and nitric oxide activity. A correct diagnosis is mandatory, because it is possible only for pulmonary arterial hypertension to use specific drugs that are able to control the symptomatic condition and the evolution of the disease. According to the most recent guidelines, for the patients with systemic sclerosis, also without pulmonary hypertension symptoms, echocardiography screening for the detection of pulmonary hypertension is recommended. Pulmonary arterial hypertension screening programs in systemic sclerosis patients is able to identify milder forms of the disease, allowing earlier management and better long-term outcome.

Treatment patterns, healthcare resource utilization, and healthcare costs among patients with pulmonary arterial hypertension in a real-world US database

Several new medications for pulmonary arterial hypertension (PAH) have recently been introduced; however, current real-world data regarding US patients with PAH are limited. We conducted a retrospective administrative claims study to examine PAH treatment patterns and summarize healthcare utilization and costs among patients with newly diagnosed PAH treated in US clinical practice. Patients newly treated for PAH from 1 January 2010 to 31 March 2015 were followed for ≥12 months. Patient characteristics, treatment patterns, healthcare resource utilization, and costs were described. Adherence (proportion of days covered), persistence (months until therapy discontinuation/modification), and the probability of continuing the index regimen were analyzed by index regimen cohort (monotherapy versus combination therapy). Of 1637 eligible patients, 93.8% initiated treatment with monotherapy and 6.2% with combination therapy. The most common index regimen was phosphodiesterase type 5 inhibitor (PDE-5I) monotherapy (70.0% of patients). A total of 581 patients (35.5%) modified their index regimen during the study. Most patients (55.4%) who began combination therapy did so on or within six months of the index date. Endothelin receptor agonists (ERAs) and combination therapies were associated with higher adherence than PDE-5Is and monotherapies, respectively. Healthcare utilization was substantial across the study population, with costs in the combination therapy cohort more than doubling from baseline to follow-up. The majority of patients were treated with monotherapies (most often, PDE-5Is), despite combination therapies and ERAs being associated with higher medication adherence. Index regimen adjustments occurred early and in a substantial proportion of patients, suggesting that inadequate clinical response to monotherapies may not be uncommon.

Applicability and added value of novel methods to improve drug development in rare diseases

BACKGROUND

The ASTERIX project developed a number of novel methods suited to study small populations. The objective of this exercise was to evaluate the applicability and added value of novel methods to improve drug development in small populations, using real world drug development programmes as reported in European Public Assessment Reports.

METHODS

The applicability and added value of thirteen novel methods developed within ASTERIX were evaluated using data from 26 European Public Assessment Reports (EPARs) for orphan medicinal products, representative of rare medical conditions as predefined through six clusters. The novel methods included were 'innovative trial designs' (six methods), 'level of evidence' (one method), 'study endpoints and statistical analysis' (four methods), and 'meta-analysis' (two methods) and they were selected from the methods developed within ASTERIX based on their novelty; methods that discussed already available and applied strategies were not included for the purpose of this validation exercise. Pre-requisites for application in a study were systematized for each method, and for each main study in the selected EPARs it was assessed if all pre-requisites were met. This direct applicability using the actual study design was firstly assessed. Secondary, applicability and added value were explored allowing changes to study objectives and design, but without deviating from the context of the drug development plan. We evaluated whether differences in applicability and added value could be observed between the six predefined condition clusters.

RESULTS AND DISCUSSION

Direct applicability of novel methods appeared to be limited to specific selected cases. The applicability and added value of novel methods increased substantially when changes to the study setting within the context of drug development were allowed. In this setting, novel methods for extrapolation, sample size re-assessment, multi-armed trials, optimal sequential design for small sample sizes, Bayesian sample size re-estimation, dynamic borrowing through power priors and fall-back tests for co-primary endpoints showed most promise - applicable in more than 40% of evaluated EPARs in all clusters. Most of the novel methods were applicable to conditions in the cluster of chronic and progressive conditions, involving multiple systems/organs. Relatively fewer methods were applicable to acute conditions with single episodes. For the chronic clusters, Goal Attainment Scaling was found to be particularly applicable as opposed to other (non-chronic) clusters.

CONCLUSION

Novel methods as developed in ASTERIX can improve drug development programs. Achieving optimal added value of these novel methods often requires consideration of the entire drug development program, rather than reconsideration of methods for a specific trial. The novel methods tested were mostly applicable in chronic conditions, and acute conditions with recurrent episodes.

Endothelin-receptor antagonists in the management of pulmonary arterial hypertension: where do we stand?

Pulmonary arterial hypertension, a disease largely neglected until a few decades ago, is presently the object of intense studies by several research teams. Despite considerable progress, pulmonary arterial hypertension remains a major clinical problem, because it is not always easy to diagnose, treat, and prevent. The disease was considered incurable until the late 1990s, when Epoprostenol was introduced as the first tool against this illness. More recently, therapy for pulmonary arterial hypertension gained momentum after publication of the SERAPHIN and AMBITION trials, which also highlighted the importance of upfront therapy. This review also focuses on recent substudies from these trials and progress in drugs targeting the endothelin pathway. Future perspectives with regard to endothelin-receptor antagonists are also discussed.

Nitric oxide signalling in cardiovascular health and disease

Nitric oxide (NO) signalling has pleiotropic roles in biology and a crucial function in cardiovascular homeostasis. Tremendous knowledge has been accumulated on the mechanisms of the nitric oxide synthase (NOS)-NO pathway, but how this highly reactive, free radical gas signals to specific targets for precise regulation of cardiovascular function remains the focus of much intense research. In this Review, we summarize the updated paradigms on NOS regulation, NO interaction with reactive oxidant species in specific subcellular compartments, and downstream effects of NO in target cardiovascular tissues, while emphasizing the latest developments of molecular tools and biomarkers to modulate and monitor NO production and bioavailability.

Pulmonary arterial hypertension: tailoring treatment to risk in the current era

Recent advances in the treatment of pulmonary arterial hypertension (PAH) have led to improved patient outcomes. Multiple PAH therapies are now available and optimising the use of these drugs in clinical practice is vital. In this review, we discuss the management of PAH patients in the context of current treatment guidelines and supporting clinical evidence. In clinical practice, considerable emphasis is placed on the importance of making treatment decisions guided by each patient's risk status, which should be assessed using multiple prognostic parameters. As PAH is a progressive disease, regular assessments are essential to ensure that any change in risk is detected in a timely manner and treatment is adjusted accordingly. With the availability of therapies that target three different pathogenic pathways, combination therapy is now the standard of care. For most patients, this involves dual combination therapy with agents targeting the endothelin and nitric oxide pathways. Therapies targeting the prostacyclin pathway should be added for patients receiving dual combination therapy who do not achieve a low-risk status. There is also a need for a holistic approach to treatment beyond pharmacological therapies. Implementation of all these approaches will ensure that PAH patients receive maximal benefit from currently available therapies.

Optimal PAH treatment requires frequent multiparameter risk assessment and early initiation of combination therapyhttp://ow.ly/IA6t30fPceT

Combination therapy in pulmonary arterial hypertension: recent accomplishments and future challenges

Pulmonary arterial hypertension (PAH) is a life-threatening disease characterized by a progressive increase in pulmonary vascular resistance, ultimately leading to right heart failure and death. Throughout the past 20 years, numerous specific pharmacologic agents, including phosphodiesterase-5 inhibitors, endothelin receptor antagonists, prostaglandins, and more recently, soluble guanylate cyclase stimulators and selective IP prostacyclin receptor agonist, have emerged for the treatment of PAH. Early clinical trials were typically of short-term duration, comparing the effects of PAH-targeted therapies versus placebo and using exercise tolerance as the primary endpoint in most trials. A meta-analysis of these trials documented a reduction in short-term mortality of ∼40% with monotherapy. More recently, we have witnessed a progressive shift in PAH study designs using longer event-driven trials comparing the effects of upfront and sequential combination therapy on clinical worsening that is perceived as a more clinically relevant outcome measure. Recent meta-analyses also documented that combination therapy significantly reduced the risk of clinical worsening by ∼35% compared with monotherapy alone.

In this review article, we will discuss the evolution of treatments and clinical trial design in the field of PAH over the past decades with a special focus on combination therapy and its current role in the management of PAH. We will also detail unresolved questions regarding the future of PAH patients’ care and the challenges of future clinical trials.

Beyond a single pathway: combination therapy in pulmonary arterial hypertension

There is a strong rationale for combining therapies to simultaneously target three of the key pathways implicated in the pathogenesis of pulmonary arterial hypertension (PAH). Evidence to support this strategy is growing, and a number of studies have demonstrated that combination therapy, administered as either a sequential or an initial regimen, can improve long-term outcomes in PAH. Dual combination therapy with a phosphodiesterase-5 inhibitor and an endothelin receptor antagonist is the most widely utilised combination regimen. However, some patients fail to achieve their treatment goals on dual therapy and may benefit from the addition of a third drug. The use of triple therapy in clinical practice was previously reserved for patients with severe disease due to the need for parenteral administration of prostanoids. Although triple therapy with parenteral prostanoids plays a key role in the management of severe PAH, the approval of oral therapies that target the prostacyclin pathway means that all three pathways can now be targeted with oral drugs at an earlier disease stage. Furthermore, there is evidence demonstrating that this approach can delay disease progression. Based on the evidence available, it is becoming increasingly clear that all PAH patients should be offered the benefits of combination therapy.

Risk assessment in pulmonary arterial hypertension

Regular patient assessment is essential for the management of chronic diseases, such as pulmonary arterial hypertension (PAH). Comprehensive patient assessment and risk stratification in PAH are important to guide treatment decisions and to monitor disease progression as well as patients' response to treatment. Approaches for assessing risk in PAH patients include the use of risk variables, as recommended in the 2015 European Society of Cardiology (ESC)/European Respiratory Society (ERS) pulmonary hypertension (PH) guidelines, and the application of risk equations and scores, such as the French registry risk equation and the REVEAL registry risk score. Risk stratification and risk scores are both useful predictors of survival on a population basis, and provide an estimate for individual patients' risk. The 2015 ESC/ERS PH guidelines recommend regular assessment of multiple variables at an expert centre. The respective merits and limitations of different risk assessment methods in PAH are discussed in this article, as well as some considerations that can be taken into account in the future development of risk assessment tools.

Regular risk assessment with multiple parameters evaluates PAH disease progression and treatment responsehttp://ow.ly/Nq0I305kgpU

Endothelin inhibitors lower pulmonary vascular resistance and improve functional capacity in patients with Fontan circulation

OBJECTIVES

To evaluate the effects of endothelin inhibitors (ERAs) on hemodynamic and functional parameters in patients post-Fontan procedure with high pulmonary vascular resistance (PVR).

METHODS

Among our cohort of patients with Fontan circulation, 8 children, 8 adolescents, and 8 adults had PVR ≥2 WU*m². These patients were treated with ERAs (minors with bosentan, adults with macitentan) and reevaluated after 6 months. Pre- and posttreatment hemodynamic variables were assessed by cardiac catheterization. Functional capacity was evaluated by cardiopulmonary exercise testing (CPET). Our primary endpoint was to obtain a reduction of PVR; the secondary endpoint was to obtain an improvement of functional capacity.

RESULTS

Under treatment, New York Heart Association class improved for adolescents and adults. PVR decreased (P = .01) in all groups: in children from the median value 2.3 (interquartile range 2.0-3.1) to 1.9 (1.4-2.3) WU*m², in adolescents from 2.3 (2.1-2.4) to 1.7 (1.4-1.8) WU*m², and in adults from 2.8 (2.0-4.7) to 2.1 (1.8-2.8)WU*m². In 71% of patients, PVR fell to less than 2 WU*m². Cardiac index increased in adolescents from 2.6 (2.4-3.3) to 3.6 (3.4-4.3) L/min/m², P = .04, and in adults from 2.1 (2.0-2.3) to 2.8 (2.3-4.7) L/min/m², P = .03. CPET showed that only adolescents displayed a significant functional improvement. Anaerobic threshold improved from 17 (13-19) to 18 (13-20) mL/kg/min, P = .03; oxygen consumption and VO₂ max increased from 1.3 (1.0-1.6) to 1.7 (1.1-1.9) L/min, P = .02 and from 25 (21-28) to 28 (26-31) L/min, P = .02, respectively. Oxygen pulse increased from 7.9 (5.7-10.4) to 11.2 (8.2-13.0) L/beat, P = .01.

CONCLUSIONS

This is the first study that assesses by cardiac catheterization and CPET the effects of ERA in patients with Fontan circulation with increased PVR. These results suggest that ERAs might provide most pronounced hemodynamic and functional improvement in adults and adolescents.

Macitentan: A Review in Pulmonary Arterial Hypertension

Macitentan (Opsumit^®) is an orally active, potent, dual endothelin (ET) receptor antagonist that is indicated for the treatment of pulmonary arterial hypertension (PAH). In the pivotal SERAPHIN trial in patients aged ≥12 years with PAH, the risk of first PAH-related event or all-cause death (primary composite endpoint) was significantly reduced by 45 % with oral macitentan 10 mg once daily versus placebo. Macitentan significantly reduced the risk of the primary composite endpoint across various patient subgroups. The risk of all-cause hospitalization and PAH-related hospitalization was also significantly reduced by macitentan, according to post hoc analysis. Macitentan was generally well tolerated in SERAPHIN. In conclusion, macitentan is an important option for the treatment of PAH.

Recent advances in the management of pulmonary arterial hypertension

Over the past 20 years, there has been an explosion in the development of therapeutics to treat pulmonary arterial hypertension (PAH), a rare but life-threatening disorder associated with progressive elevation of pulmonary pressures and severe right heart failure. Recently, the field has seen the introduction of riociguat, a soluble guanylate cyclase stimulator, a new endothelin receptor antagonist (macitentan), and oral prostanoids (treprostinil and selexipag). Besides new drugs, there have been significant advances in defining the role of upfront combination therapy in treatment-naïve patients as well as proposed methods to deliver systemic prostanoids by use of implantable pumps. In this review, we will touch upon the most important developments in PAH therapeutics over the last three years and how these have changed the guidelines for the treatment of PAH. These exciting developments herald a new era in the treatment of PAH which will be punctuated by the use of more clinically relevant endpoints in clinical research trials and a novel treatment paradigm that may involve upfront double- or triple-combination therapy. We anticipate that the future will make use of these strategies to test the efficacy of upcoming new drugs that aspire to reduce disease progression and improve survival in patients afflicted with this devastating disease.

Endothelin research and the discovery of macitentan for the treatment of pulmonary arterial hypertension

Endothelin receptor antagonists (ERAs) are used for the treatment of pulmonary arterial hypertension (PAH). Macitentan, a dual (ETA+ETB) ERA approved for the long-term treatment of PAH, was discovered through a tailored research program aimed at improving efficacy and safety over the existing ERAs. The goal of improved efficacy was based on the understanding that not only the ETA receptor but also the ETB receptor contributed to the hemodynamic and structural changes induced by endothelin-1 (ET-1) in pathological conditions and on the predefined requirements for optimal tissue penetration and binding kinetics of the antagonist. The goal of improved safety was based on the discovery of the role of ETB receptors in vascular permeability and vasopressin release and on the elucidation of the mechanism by which bosentan (the first approved oral dual ETA/ETB ERA) caused liver enzyme changes. Our intention was to design a molecule that would block ETA and ETB receptors optimally and would not interfere with bile salt elimination. This review takes us through the drug discovery journey that led to the discovery, development, and registration of macitentan.

[The new endothelin receptor antagonist macitentan: Prospects for therapy of pulmonary arterial hypertension]

Pulmonary arterial hypertension (PAH) is a clinical group of severe and rare diseases with similar morphological, hemodynamic, and therapeutic characteristics. One of the novel drugs to treat PAH is macitentan, a new double endothelin ETA and ETB receptor antagonist that is characterized by special physicochemical properties, ensuring the penetration of the drug into tissues and its improved receptor-binding properties. The SERAPHIN trial has demonstrated that therapy with macitentan 10 mg versus placebo statistically significantly reduces the risk of poor outcomes and death by 45%. The treatment with macitentan 10 is observed to be highly effective regardless of the presence/absence of basic PAH-specific therapy. The drug considerably improves clinically important outcomes, including 6-minute walk distance and WHO functional class. Macitentan exerts a steady-state therapeutic effect, by improving pulmonary hemodynamics. Macitentan 10 mg statistically significantly reduces the risk of PAH, frequency of its related hospitalizations, and the number of days spent in hospital. The drug has a favorable safety profile; its most common side effects are headache, nasopharyngitis, and anemia. Macitentan is an effective first-line drug to improve long-term outcomes in patients with newly and previously diagnosed PAH.

Connective tissue disease-related pulmonary arterial hypertension

Over the past two decades, there have been several advances in the assessment and management of connective tissue disease-related pulmonary arterial hypertension (CTD-PAH) that improved outcomes of the treatment of this lethal disease, and this will be the focus of this study. Systemic sclerosis is the leading cause of CTD-PAH, followed by systemic lupus erythematosus, mixed connective tissue disease, idiopathic inflammatory myositis, rheumatoid arthritis, and Sjogren's syndrome. Clinical registries have been invaluable in informing about the burden of disease, risk and prognostic factors, and temporal trends with respect to treatment and outcome in CTD-PAH. The major advances have centered on improved disease classification and diagnostic criteria, screening and early diagnosis, the emergence of evidence-based therapies including combination goal-orientated treatment strategies, and the establishment of centers with expertise in PAH.

Predictors of long-term outcomes in patients treated with riociguat for pulmonary arterial hypertension: data from the PATENT-2 open-label, randomised, long-term extension trial

BACKGROUND

Pulmonary arterial hypertension is a chronic disease associated with poor long-term outcomes. Identifying predictors of long-term outcome in pulmonary arterial hypertension is important to assess disease severity and guide treatment. We investigate associations between efficacy parameters and long-term outcomes in patients with pulmonary arterial hypertension receiving riociguat in the PATENT-2 study. We also present safety and efficacy data from the final data cutoff of PATENT-2, where most patients had received at least 2 years of riociguat treatment.

METHODS

Eligible patients from the PATENT-1 study entered the PATENT-2 open-label extension, which will continue until all patients transition to the commercial drug. All patients received riociguat individually adjusted to a maximum dose of 2·5 mg three times a day. The primary endpoint was safety and tolerability, assessed with recording adverse events, serious adverse events, discontinuations, and deaths; exploratory assessments included 6-min walking distance (6MWD), WHO functional class, N-terminal prohormone of brain natriuretic peptide (NT-proBNP)concentrations, Borg dyspnoea score, health-related quality of life (EQ-5D score), survival, and clinical worsening-free survival. Association between efficacy parameters and long-term outcomes was assessed using Kaplan-Meier analyses and a Cox proportional-hazards regression model. PATENT-2 is registered at ClinicalTrials.gov, number NCT00863681.

FINDINGS

396 patients entered PATENT-2, of whom 197 patients were receiving riociguat monotherapy and 199 were receiving riociguat in combination with endothelin receptor antagonists or prostanoids, or both. A significant association was noted between 6MWD, NT-proBNP concentration, and WHO functional class and overall survival at baseline (p=0·0006, 0·0225, and 0·0191, respectively), and at follow-up (p=0·021, 0·0056, and 0·0048, respectively). Riociguat was well tolerated in PATENT-2. Serious adverse events were recorded in 238 (60%) of the total population, and 45 (11%) patients discontinued treatment because of an adverse event. Improvements in 6MWD, WHO functional class, and NT-proBNP concentrations were maintained after 2 years of treatment.

INTERPRETATION

These results support the long-term use of riociguat in patients with pulmonary arterial hypertension, and emphasise the prognostic value of 6MWD, WHO functional class, and NT-proBNP concentrations.

FUNDING

Bayer Pharma AG.

BMPR2 mutations and survival in pulmonary arterial hypertension: an individual participant data meta-analysis

BACKGROUND

Mutations in the gene encoding the bone morphogenetic protein receptor type II (BMPR2) are the commonest genetic cause of pulmonary arterial hypertension (PAH). However, the effect of BMPR2 mutations on clinical phenotype and outcomes remains uncertain.

METHODS

We analysed individual participant data of 1550 patients with idiopathic, heritable, and anorexigen-associated PAH from eight cohorts that had been systematically tested for BMPR2 mutations. The primary outcome was the composite of death or lung transplantation. All-cause mortality was the secondary outcome. Hazard ratios (HRs) for death or transplantation and all-cause mortality associated with the presence of BMPR2 mutation were calculated using Cox proportional hazards models stratified by cohort.

FINDINGS

Overall, 448 (29%) of 1550 patients had a BMPR2 mutation. Mutation carriers were younger at diagnosis (mean age 35·4 [SD 14·8] vs 42·0 [17·8] years), had a higher mean pulmonary artery pressure (60·5 [13·8] vs 56·4 [15·3] mm Hg) and pulmonary vascular resistance (16·6 [8·3] vs 12·9 [8·3] Wood units), and lower cardiac index (2·11 [0·69] vs 2·51 [0·92] L/min per m(2); all p<0·0001). Patients with BMPR2 mutations were less likely to respond to acute vasodilator testing (3% [10 of 380] vs 16% [147 of 907]; p<0·0001). Among the 1164 individuals with available survival data, age-adjusted and sex-adjusted HRs comparing BMPR2 mutation carriers with non-carriers were 1·42 (95% CI 1·15-1·75; p=0·0011) for the composite of death or lung transplantation and 1·27 (1·00-1·60; p=0·046) for all-cause mortality. These HRs were attenuated after adjustment for potential mediators including pulmonary vascular resistance, cardiac index, and vasoreactivity. HRs for death or transplantation and all-cause mortality associated with BMPR2 mutation were similar in men and women, but higher in patients with a younger age at diagnosis (p=0·0030 for death or transplantation, p=0·011 for all-cause mortality).

INTERPRETATION

Patients with PAH and BMPR2 mutations present at a younger age with more severe disease, and are at increased risk of death, and death or transplantation, compared with those without BMPR2 mutations.

FUNDING

Cambridge NIHR Biomedical Research Centre, Medical Research Council, British Heart Foundation, Assistance Publique-Hôpitaux de Paris, INSERM, Université Paris-Sud, Intermountain Research and Medical Foundation, Vanderbilt University, National Center for Advancing Translational Sciences, National Institutes of Health, National Natural Science Foundation of China, and Beijing Natural Science Foundation.