Clinical worsening in trials of pulmonary arterial hypertension: results and implications

Effect of ambrisentan in patients with systemic sclerosis and mild pulmonary arterial hypertension: long-term follow-up data from EDITA study

BACKGROUND

In the EDITA trial, patients with systemic sclerosis (SSc) and mild pulmonary vascular disease (PVD) treated with ambrisentan had a significant decline of pulmonary vascular resistance (PVR) but not of mean pulmonary arterial pressure (mPAP) vs. placebo after six months. The EDITA-ON study aimed to assess long-term effects of open label therapy with ambrisentan vs. no pulmonary arterial hypertension (PAH) therapy.

METHODS

Patients who participated in the EDITA study and received regular follow-up were included in EDITA-ON. Clinical, echocardiographic, laboratory, exercise and hemodynamic parameters during follow-up were analysed. The primary endpoint was to assess whether continued treatment with ambrisentan vs. no treatment prevented the development of PAH according to the new definition.

RESULTS

Of 38 SSc patients included in the EDITA study four were lost to follow-up. Of the 34 remaining patients (age 55 ± 11 years, 82.1% female subjects), 19 received ambrisentan after termination of the blinded phase, 15 received no PAH medication. The mean follow-up time was 2.59 ± 1.47 years, during which 29 patients underwent right heart catheterization. There was a significant improvement of mPAP in catheterised patients receiving ambrisentan vs. no PAH treatment (-1.53 ± 2.53 vs. 1.91 ± 2.98 mmHg, p = 0.003). In patients without PAH treatment 6/12 patients had PAH vs. 1/17 of patients receiving ambrisentan (p < 0.0001).

CONCLUSION

In SSc patients with early PVD, the development of PAH and/or deterioration was less frequent among patients receiving ambrisentan, indicating that early treatment and close follow-up could be beneficial in this high-risk group. Future trials in this field are needed to confirm these results.

Association of risk assessment at diagnosis with healthcare resource utilization and health-related quality of life outcomes in pulmonary arterial hypertension

We aimed to describe the clinical characteristics, healthcare resource utilization (HCRU) and costs, health-related quality of life (HRQoL), and survival for patients with pulmonary arterial hypertension (PAH), stratified by 1-year mortality risk at diagnosis. Adults diagnosed with PAH at the Sheffield Pulmonary Vascular Disease Unit between 2012 and 2019 were included. Patients were categorized as low, intermediate, or high risk for 1-year mortality at diagnosis. Demographics, clinical characteristics, comorbidities, HCRU, costs, HRQoL, and survival were analyzed. Overall, 1717 patients were included: 72 (5%) at low risk, 941 (62%) at intermediate risk, and 496 (33%) at high risk. Low-risk patients had lower HCRU prediagnosis and 1-year postdiagnosis than intermediate- or high-risk patients. Postdiagnosis, there were significant changes in HCRU, particularly inpatient hospitalizations and accident and emergency (A&E) visits among high-risk patients. At 3 years postdiagnosis, HCRU for all measures was similar across risk groups. Low-risk patients had lower EmPHasis-10 scores (indicating better HRQoL) at diagnosis and at 1-year follow-up compared with intermediate- and high-risk patients; only the score in the high-risk group improved. Median overall survival decreased as risk category increased in analyzed subgroups. Low-risk status was associated with better 1-year survival and HRQoL compared with intermediate- and high-risk patients. HCRU decreased in high-risk patients postdiagnosis, with the most marked reduction in A&E admissions. The pattern of decreased per-patient inpatient hospitalizations and A&E visits at 3 years postdiagnosis suggests that a diagnosis of PAH helps to decrease HCRU in areas that are key drivers of costs.

Real-world treatment patterns, healthcare resource utilization, and cost among adults with pulmonary arterial hypertension in the United States

Treatment for pulmonary arterial hypertension (PAH) has evolved over the past decade, including approval of new medications and growing evidence to support earlier use of combination therapy. Despite these changes, few studies have assessed real-world treatment patterns, healthcare resource utilization (HCRU), and costs among people with PAH using recent data. We conducted a retrospective cohort study using administrative claims from the HealthCore Integrated Research Database®. Adult members with claims for a PAH diagnosis, right heart catheterization, and who initiated PAH treatment (index date) between October 1, 2015 and November 30, 2020 were identified. Members had to be continuously enrolled in the health plan for 6 months before the index date (baseline) and ≥30 days after. Treatment patterns, HCRU, and costs were described. A total of 843 members with PAH (mean age 62.3 years, 64.2% female) were included. Only 21.0% of members received combination therapy as their first-line treatment, while most members (54.6%) received combination therapy as second-line treatment. All-cause HCRU remained high after treatment initiation with 58.0% of members having ≥1 hospitalization and 41.3% with ≥1 emergency room visit. Total all-cause costs declined from $15,117 per patient per month at baseline to $14,201 after treatment initiation, with decreased medical costs ($14,208 vs. $6,349) more than offsetting increased pharmacy costs ($909 vs. $7,852). In summary, despite growing evidence supporting combination therapy, most members with PAH initiated treatment with monotherapy. Total costs decreased following treatment, driven by a reduction in medical costs even with increases in pharmacy costs.

Riociguat for Sarcoidosis-Associated Pulmonary Hypertension: Results of a 1-Year Double-Blind, Placebo-Controlled Trial

BACKGROUND

Riociguat is effective in delaying the time to clinical worsening (TCW) in patients with groups 1 and 4 pulmonary hypertension.

RESEARCH QUESTION

Is riociguat more effective than placebo in prolonging TCW in sarcoidosis-associated pulmonary hypertension (SAPH)?

STUDY DESIGN AND METHODS

This was a double-blind placebo-controlled trial. Patients with SAPH confirmed by right heart catheterization were randomized 1:1 to riociguat or placebo. Patients underwent 6-min walk distance (6MWD) and spirometry testing every 8 weeks. The primary end point was TCW, which was defined by the time to the first of the following: (1) all-cause mortality, (2) need for hospitalization because of worsening cardiopulmonary status attributable to progression of disease, (3) > 50 m decrease in the 6MWD test, or (4) worsening of World Health Organization functional class.

RESULTS

A total of 16 patients were randomized to riociguat (n = 8) or placebo (n = 8). No difference was found in pulmonary artery mean, pulmonary vascular resistance, initial 6MWD, or FVC between the two groups. Five of eight patients who received placebo met TCW criteria, whereas none of the patients who received riociguat experienced a qualifying event. By log-rank analysis, patients who received riociguat were in the study for a significantly longer period (χ ² = 6.259; P = .0124). The 6MWD decreased in the placebo group (median, -55.9 m; range, -176.8 to 60 m), but rose in the riociguat group (median, +42.7 m; range, -7.5 to +91.4 m; P = .0149), with a placebo-corrected difference of 94 m (P < .01). Four of eight patients who received riociguat, but only 1 of 8 patients who received placebo, showed a > 30-m improvement in 6MWD (P > .05). No significant adverse events associated with riociguat occurred.

INTERPRETATION

Over the 1 year of the study, riociguat was effective in preventing clinical worsening and improving exercise capacity in patients with SAPH.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT02625558; URL: www.clinicaltrials.gov.

Cardiac-MRI Predicts Clinical Worsening and Mortality in Pulmonary Arterial Hypertension: A Systematic Review and Meta-Analysis

OBJECTIVES

This meta-analysis evaluates assessment of pulmonary arterial hypertension (PAH), with a focus on clinical worsening and mortality.

BACKGROUND

Cardiac magnetic resonance (CMR) has prognostic value in the assessment of patients with PAH. However, there are limited data on the prediction of clinical worsening, an important composite endpoint used in PAH therapy trials.

METHODS

The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, and Web of Science databases were searched in May 2020. All CMR studies assessing clinical worsening and the prognosis of patients with PAH were included. Pooled hazard ratios of univariate regression analyses for CMR measurements, for prediction of clinical worsening and mortality, were calculated.

RESULTS

Twenty-two studies with 1,938 participants were included in the meta-analysis. There were 18 clinical worsening events and 8 deaths per 100 patient-years. The pooled hazard ratios show that every 1% decrease in right ventricular (RV) ejection fraction is associated with a 4.9% increase in the risk of clinical worsening over 22 months of follow-up and a 2.1% increase in the risk of death over 54 months. For every 1 ml/m2 increase in RV end-systolic volume index or RV end-diastolic volume index, the risk of clinical worsening increases by 1.3% and 1%, respectively, and the risk of mortality increases by 0.9% and 0.6%. Every 1 ml/m2 decrease in left ventricular stroke volume index or left ventricular end-diastolic volume index increased the risk of death by 2.5% and 1.8%. Left ventricular parameters were not associated with clinical worsening.

CONCLUSIONS

This review confirms CMR as a powerful prognostic marker in PAH in a large cohort of patients. In addition to confirming previous observations that RV function and RV and left ventricular volumes predict mortality, RV function and volumes also predict clinical worsening. This study provides a strong rationale for considering CMR as a clinically relevant endpoint for trials of PAH therapies.

Contemporary Pharmacotherapeutic Approach in Pulmonary Arterial Hypertension

Since the 1973 World Symposium on Pulmonary Hypertension, advancements in the understanding of pathophysiology and pathobiology have led to a myriad of pharmacotherapies for the disease. This article journeys through the development of therapeutic approaches for pulmonary arterial hypertension.

Comparative effectiveness of oral prostacyclin pathway drugs on hospitalization in patients with pulmonary hypertension in the United States: a retrospective database analysis

Two oral medications targeting the prostacyclin pathway are available to treat pulmonary arterial hypertension in the United States: oral treprostinil and selexipag. We compared real-world hospitalization in patients receiving these medications. A retrospective administrative claims study was conducted using the Optum® Clinformatics® Data Mart database. Patients with pulmonary hypertension were identified using diagnostic codes. Cohort inclusion required age ≥ 18 years, first oral treprostinil or selexipag prescription between 1 January 2015 and 30 September 2017 (index date), and continuous enrollment in the prior ≥6 months. Patients who switched index drug were excluded. Follow-up was from index date until the first of end of index drug exposure, end of continuous enrollment, death, or 31 December 2017. Multivariable Cox proportional hazard and Poisson regression were used to compare risk and rate, respectively, of hospitalization associated with oral treprostinil vs. selexipag, adjusting for potential confounders. The study cohort included 99 patients receiving oral treprostinil and 123 receiving selexipag. Mean age was 61 years, and most patients were females (71%). Compared with oral treprostinil, selexipag was associated with a 46% lower risk of all-cause hospitalization (hazard ratio 0.54, 95% confidence interval 0.31, 0.92; P = 0.02), a 47% lower risk of pulmonary hypertension-related hospitalization (hazard ratio 0.53, 95% confidence interval 0.31, 0.93; P = 0.03), a 42% lower all-cause hospitalization rate (rate ratio 0.58, 95% confidence interval 0.39, 0.87; P = 0.01), and a 46% lower pulmonary hypertension-related hospitalization rate (rate ratio 0.54, 95% confidence interval 0.35, 0.82; P = 0.004). This study suggests that selexipag is associated with lower hospitalization risk and rate than oral treprostinil.

Burden of pulmonary hypertension in patients with portal hypertension in the United States: a retrospective database study

Patients with portal hypertension may develop pulmonary hypertension. The economic implications of these comorbidities have not been systematically assessed. We compared healthcare resource utilization and costs in the United States between patients with co-existing portal hypertension and pulmonary hypertension (pulmonary hypertension cohort) and a matched cohort of portal hypertension patients without pulmonary hypertension (control cohort). In this retrospective analysis, adult pulmonary hypertension and control patients were identified from the Optum® Clinformatics® Data Mart database between 1 July 2014 and 30 June 2018. All patients had ≥2 claims with diagnosis codes for portal hypertension; pulmonary hypertension patients had ≥2 claims with diagnosis codes for pulmonary hypertension; controls could not have pulmonary hypertension diagnoses or any claims for pulmonary arterial hypertension-specific medications. Controls were matched to pulmonary hypertension patients by age, sex, Charlson comorbidity index score, and liver diseases. We assessed 12-month healthcare resource utilization and costs. Each cohort included 146 patients. During follow-up, pulmonary hypertension cohort patients were more likely than controls to experience a hospitalization (51% vs. 32%, P = 0.0014) and an emergency room visit (55% vs. 41%, P = 0.026). The average annual total cost was higher in pulmonary hypertension patients than for matched controls ($119,912 vs. $81,839, P < 0.0001). After covariate adjustment, costs for pulmonary hypertension cohort patients were 1.47 times higher than those for controls (P = 0.0197). These findings suggest that patients with portal hypertension and co-existing pulmonary hypertension are at a greater risk for hospitalization and incur higher mean annual total costs than portal hypertension patients without pulmonary hypertension.

Medication adherence, hospitalization, and healthcare resource utilization and costs in patients with pulmonary arterial hypertension treated with endothelin receptor antagonists or phosphodiesterase type-5 inhibitors

Adherence to therapy for pulmonary arterial hypertension is essential to optimize patient outcomes, but data on real-world adherence to different pulmonary arterial hypertension drug classes are limited. This retrospective database analysis evaluated relationships between adherence, hospitalization, and healthcare costs in pulmonary arterial hypertension patients treated with endothelin receptor antagonists or phosphodiesterase type-5 inhibitors. From the IQVIA Adjudicated Health Plan Database, patients with pulmonary arterial hypertension were identified based on diagnostic codes and prescriptions for endothelin receptor antagonists (ambrisentan, bosentan, macitentan) or phosphodiesterase type-5 inhibitors (sildenafil, tadalafil) approved for pulmonary arterial hypertension. Patients were assigned to the class of their most recently initiated (index) pulmonary arterial hypertension therapy between 1 January 2009 and 30 June 2015. Medication adherence was measured by proportion of days covered; patients with proportion of days covered ≥80% were considered adherent. The proportion of adherent patients was higher for endothelin receptor antagonists (571/755; 75.6%) than for phosphodiesterase type-5 inhibitors (970/1578; 61.5%; P < 0.0001). In both groups, hospitalizations declined as proportion of days covered increased. Among adherent patients, those on endothelin receptor antagonists had a significantly lower hospitalization rate than those on phosphodiesterase type-5 inhibitors (23.1% versus 28.5%, P = 0. 0218), fewer hospitalizations (mean (standard deviation) 0.4 (0.8) versus 0.5 (0.9); P = 0.02), and mean hospitalization costs during the six-month post-index ($9510 versus $15,726, P = 0.0318). Increasing adherence reduced hospitalization risk more for endothelin receptor antagonists than for phosphodiesterase type-5 inhibitors (hazard ratio 0.176 versus 0.549, P = 0.001). Rates and numbers of rehospitalizations within 30 days post-discharge were similar between groups. Mean total costs were higher with endothelin receptor antagonists than phosphodiesterase type-5 inhibitors in all patients ($91,328 versus $72,401, P = 0.0003) and in adherent patients ($88,867 versus $56,300, P < 0.0001), driven by higher drug costs.

National trends and outcomes of hospitalizations for pulmonary hypertension in Spain (2001-2014)

OBJECTIVE

To assess changes in incidence, diagnostic procedures, comorbidity profiles, length of hospital stay (LOHS), costs, and in-hospital mortality (IHM) for patients hospitalized with pulmonary hypertension (PH).

METHODS

We included patients hospitalized with PH in Spain from 2001 to 2014. The data were collected from the National Hospital Discharge Database.

RESULTS

We included 644,436 discharges (43.31% males and 56.09% females) admitted for primary PH (8.34%) or secondary PH (91.66%). The crude incidence rate increased from 58.67 to 148.32 hospitalizations per 100,000 inhabitants between 2001 and 2002 and 2013-2014 (p < 0.001). The percentage of patients with a Charlson comorbidity index ≥2 was 27.87% in 2001-2002, increasing to 47.02% in 2013-2014 (p < 0.001). IHM was 8.77%, with a reduction in the value yielded by the multivariable analysis between 2009 and 2010 and 2013-2014. Median LOHS was 9 ± 9 days in 2001-2002, which decreased to 7 ± 8 days in 2013-2014 (p < 0.001). The mean cost per patient increased from €3352.4 ± €1495 in the period 2001-2002 to €4198.94 ± €1287.96 in 2013-2014 (p < 0.001).

CONCLUSIONS

Despite the increase over time in hospital admissions for PH, associated comorbidity, and costs, LOHS and IHM decreased, suggesting that the management of PH-related hospitalizations improved in Spain during the study period.

Macitentan in Pulmonary Arterial Hypertension: A Focus on Combination Therapy in the SERAPHIN Trial

SERAPHIN was a double-blind, placebo-controlled, event-driven phase III trial that evaluated the effects of long-term treatment with macitentan, an oral endothelin receptor antagonist, in patients with pulmonary arterial hypertension (PAH). The majority of patients were receiving PAH therapy at enrollment, providing the opportunity to evaluate the efficacy and safety of macitentan in combination with other PAH therapies (predominantly phosphodiesterase type 5 inhibitors [PDE-5i]). In patients receiving background therapy, macitentan reduced the risk of morbidity/mortality by 38% compared with placebo (hazard ratio [HR] 0.62; 95% confidence level [CL] 0.43-0.89; p = 0.009). Furthermore, patients receiving macitentan and background therapy had a 37% reduction in the risk of being hospitalized for PAH (HR 0.63; 95% CL 0.41-0.96) compared with patients receiving background therapy only (placebo arm). Macitentan treatment in combination with background therapy was also associated with improvements in exercise capacity, functional class, cardiopulmonary hemodynamics, and health-related quality of life compared with background therapy alone. The safety profile of macitentan as part of a combination therapy regimen was consistent with that of macitentan in the overall SERAPHIN population. The SERAPHIN study has provided evidence that combination therapy with macitentan and a PDE-5i is effective and well tolerated in the management of PAH. Based on these data, and those from subsequent long-term trials, combination therapy is increasingly recognized as an important treatment option for improving long-term outcomes in PAH.

CLINICAL TRIAL REGISTRATION NUMBER

NCT00660179.

The Modified Borg Dyspnea Scale does not predict hospitalization in pulmonary arterial hypertension

Background

Breathlessness is the most common symptom reported by patients with pulmonary arterial hypertension (PAH). The Modified Borg Dyspnea Scale (MBS) is routinely obtained during the six-minute walk test in the assessment of PAH patients, but it is not known whether the MBS predicts clinical outcomes such as hospitalizations in PAH.

Methods

We performed a retrospective study of World Health Organization (WHO) Group 1 PAH patients followed at our center. The dates of the first three MBS and hospitalizations that occurred within three months of a documented MBS were collected. Marginal Cox hazard regression modeling was used to assess for a relationship between MBS and all-cause as well as PAH-related hospitalization.

Results

A total of 50 patients were included; most (92%) were functional class III/IV, 44% and 65% were treatment-naïve prior to their first MBS and hospitalization, respectively. The first recorded MBS was inversely correlated with the first recorded six-minute walk distance (6MWD) (r = –0.41, P < 0.01) but did not track with WHO functional class (r = 0.07, P = 0.63). MBS did not predict all-cause (hazard ratio [HR], 0.91; 95% confidence interval [CI], 0.76–1.08; P = 0.28) or PAH-related hospitalization (HR, 1.04; 95% CI, 0.89–1.23; P = 0.61), though there was a strong relationship between 6MWD and PAH-related hospitalization (P = 0.01). These findings persisted after multivariable adjustment.

Conclusions

Breathlessness as assessed by MBS does not predict all-cause or PAH-related hospitalization. Robust and validated patient-reported outcomes are needed in pulmonary vascular disease.

Riociguat: a soluble guanylate cyclase stimulator for the treatment of pulmonary hypertension

Despite advances in treatments and improved survival, patients with pulmonary hypertension still experience poor exercise and functional capacity, which has a significant detrimental impact on their quality of life. The nitric oxide (NO)–soluble guanylate cyclase (sGC)–cyclic guanosine 3′,5′-monophosphate (cGMP) pathway has been shown to play an important role in cardiovascular physiology, especially in vasodilation and pulmonary vascular tone. The oral sGC stimulator riociguat has a dual mode of action on the NO–sGC–cGMP pathway: direct stimulation of sGC independent of NO and indirect simulation via sensitization of sGC to endogenous NO. Riociguat is now licensed in >50 countries worldwide, including in Europe, the USA, Canada, and Japan. Approval for the treatment of pulmonary arterial hypertension (PAH) was based on Phase III data from the PATENT studies, in which riociguat significantly improved exercise capacity, pulmonary vascular resistance, a range of secondary end points, and hemodynamic parameters in patients with symptomatic PAH. In the Phase III CHEST studies, riociguat consistently improved exercise capacity in patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH) or persistent/recurrent CTEPH after pulmonary endarterectomy and is now the only drug to be approved for this indication. Riociguat was well tolerated in long-term studies of PAH and CTEPH. This review describes the role of the NO–sGC–cGMP pathway in the pathophysiology of pulmonary hypertension, and reviews the clinical efficacy and safety of riociguat in patients with PAH and inoperable or persistent/recurrent CTEPH. Based on its demonstrated efficacy and established safety profile, riociguat is a promising treatment option for patients with PAH and CTEPH.

A simple hemodynamic parameter to predict clinical worsening in pulmonary arterial hypertension

BACKGROUND

Predicting prognosis is a cornerstone in management of pulmonary arterial hypertension. Hemodynamic parameters are among the robust indicators of right ventricular function and prognosis. In this study we have investigated the association of a simple hemodynamic parameter with clinical worsening in pulmonary arterial hypertension.

METHODS AND PATIENTS

120 patients were enrolled in a single center prospective cohort study after confirmation of precapillary pulmonary hypertension and were followed for an average of 36months on guideline recommended treatment protocols. cSvO₂ was calculated as the ratio of right atrial pressure over Mixed Venous Oxygen Saturation. Independent predictors of clinical worsening were identified using multivariable Cox regression models.

RESULTS

By the end of the follow up a total of 21 patients died and 63 were hospitalized for pulmonary hypertension. Time-to-event Cox regression model showed a strong association between cSvO₂ and time to clinical worsening (HR: 250.13, CI: (38.56-1622.34) &p-value: <0.0001).

CONCLUSION

The index of cSvO₂ includes both parameters of cardiac output and right ventricular filling pressure and might be beneficial in predicting clinical worsening in patients with pulmonary arterial hypertension.

Hemodynamic, functional, and clinical responses to pulmonary artery denervation in patients with pulmonary arterial hypertension of different causes: phase II results from the Pulmonary Artery Denervation-1 study

The mechanisms underlying pulmonary arterial hypertension (PAH) are multifactorial. The efficacy of pulmonary artery denervation (PADN) for idiopathic PAH treatment has been evaluated. This study aimed to analyze the hemodynamic, functional, and clinical responses to PADN in patients with PAH of different causes.

Efficacy and Safety of a Novel Endothelin Receptor Antagonist, Macitentan, in Japanese Patients With Pulmonary Arterial Hypertension

BACKGROUND

Macitentan is a novel, dual endothelin receptor antagonist with sustained receptor binding, used for the long-term treatment of pulmonary arterial hypertension (PAH). In the present study, we assessed the efficacy and safety of macitentan in Japanese patients with PAH.

METHODS AND RESULTS

Macitentan was administered at a once-daily dose of 10 mg in 30 patients. The primary endpoint was change in pulmonary vascular resistance (PVR) from baseline to week 24. Change to week 24 in the other hemodynamic parameters, 6-min walk distance (6MWD), World Health Organization (WHO) functional class, and plasmaN-terminal pro-brain natriuretic peptide (NT-pro-BNP), as well as time to clinical deterioration up to week 52 were also assessed as secondary endpoints. In the 28 patients on per-protocol analysis, PVR decreased from 667±293 to 417±214 dyn·sec·cm(-5)(P<0.0001). 6MWD increased from 427±128 to 494±116 m (P<0.0001). WHO functional class improved in 13 patients (46.4%) and was maintained in 15 patients (53.6%), and NT-pro-BNP was reduced by 18% (P<0.0001). The favorable treatment effect on PVR was apparent regardless of concomitant therapy for PAH.

CONCLUSIONS

Macitentan was efficacious and well tolerated and improved the hemodynamic parameters, exercise capacity, symptoms, and clinical biomarkers in Japanese PAH patients. Macitentan can be a valuable therapeutic option for Japanese patients with PAH. (

TRIAL REGISTRATION

JAPIC Clinical Trials Information [JapicCTI-121986].) (Circ J 2016; 80: 1478-1483).

Clinical Worsening as Composite Study End Point in Pediatric Pulmonary Arterial Hypertension

BACKGROUND

Clinical worsening (CW), an increasingly used composite end point in adult pulmonary arterial hypertension (PAH), has not yet been evaluated in pediatric PAH. This study aims to evaluate the usefulness of CW in pediatric PAH by assessing the event incidence and prognostic value of each separate component of CW and of the composite CW end point.

METHODS

Seventy pediatric patients with PAH from the Dutch National Network for Pediatric Pulmonary Hypertension, who started PAH-targeted therapy between January 2000 and January 2014, were included in the study and underwent standardized follow-up. The following CW components were prospectively registered: death, lung transplantation (LTx), PAH-related hospitalizations, initiation of IV prostanoids, and functional deterioration (World Health Organization functional-class deterioration, ≥ 15% decrease in 6-min walk distance, or both). The longitudinal event incidence and prognostic value were assessed for each separate component and their combination.

RESULTS

The end-point components of death, LTx, hospitalizations, initiation of IV prostanoids, and functional deterioration occurred with a longitudinal event rate of 10.1, 2.5, 21.4, 9.4 and 48.1 events per 100 person-years, respectively. The composite CW end point occurred 91.5 times per 100 person-years. The occurrences of either hospitalization, initiation of IV prostanoids, or functional deterioration were predictive of death or LTx (P < .001 for each component). In this cohort, 1-, 3-, and 5-year transplant-free survival was 76%, 64%, and 56%, respectively. Freedom from CW at 1, 3, and 5 years was 43%, 22%, and 17%, respectively.

CONCLUSIONS

CW occurred with a high event incidence and each of the soft end-point components was predictive of death or LTx. This supports the usefulness of CW as a study end point in clinical trials in pediatric PAH.

Pulmonary hypertension trials: how can we do better?

Conducting clinical trials on pulmonary hypertension in the US and Western Europe has become increasingly difficult and costly because of many challenges. These include a limited patient population that makes recruitment difficult. Recruiting internationally has helped, but can add variability. The choice of end points is important but ideal end points that reflect pathogenesis of the disease are not available. The 6-min walk distance has been used in most trials to date, but recent trials have used an 'event-driven' design, in which combined outcomes are used to reflect progression of the disease. This design has advantages but requires many hundreds of patients and may take up to several years. Thus, there is still a role for functional or hemodynamic end points to enable testing of more new agents. Assuring the safety and scientific integrity of clinical trials without excessive regulation will also help facilitate the evaluation of additional therapies for this devastating disease.

Exercise training improves peak oxygen consumption and haemodynamics in patients with severe pulmonary arterial hypertension and inoperable chronic thrombo-embolic pulmonary hypertension: a prospective, randomized, controlled trial

Aims

The impact of exercise training on the right heart and pulmonary circulation has not yet been invasively assessed in patients with pulmonary hypertension (PH) and right heart failure. This prospective randomized controlled study investigates the effects of exercise training on peak VO₂/kg, haemodynamics, and further clinically relevant parameters in PH patients.

Methods and results

Eighty-seven patients with pulmonary arterial hypertension and inoperable chronic thrombo-embolic PH (54% female, 56 ± 15 years, 84% World Health Organization functional class III/IV, 53% combination therapy) on stable disease-targeted medication were randomly assigned to a control and training group. Medication remained unchanged during the study period. Non-invasive assessments and right heart catheterization at rest and during exercise were performed at baseline and after 15 weeks. Primary endpoint was the change in peak VO₂/kg. Secondary endpoints included changes in haemodynamics. For missing data, multiple imputation and responder analyses were performed. The study results showed a significant improvement of peak VO₂/kg in the training group (difference from baseline to 15 weeks: training +3.1 ± 2.7 mL/min/kg equals +24.3% vs. control −0.2 ± 2.3 mL/min/kg equals +0.9%, P < 0.001). Cardiac index (CI) at rest and during exercise, mean pulmonary arterial pressure, pulmonary vascular resistance, 6 min walking distance, quality of life, and exercise capacity significantly improved by exercise training.

Conclusion

Low-dose exercise training at 4–7 days/week significantly improved peak VO₂/kg, haemodynamics, and further clinically relevant parameters. The improvements of CI at rest and during exercise indicate that exercise training may improve the right ventricular function. Further, large multicentre trials are necessary to confirm these results.

Early decline in six-minute walk distance from the time of diagnosis predicts clinical worsening in pulmonary arterial hypertension

BACKGROUND

The six-minute walk distance (6MWD) is commonly used to assess pulmonary arterial hypertension (PAH). However, the role of 6MWD in predicting outcomes in PAH is controversial. Clinical worsening is being increasingly considered as a clinically meaningful end point in PAH.

OBJECTIVES

We aimed to investigate whether early longitudinal changes in 6MWD (Δ6MWD) in meters and percent predicted (%pred) from the time of diagnosis predict clinical worsening of PAH.

METHODS

One hundred patients with group I PAH were retrospectively assessed. 6MWD was calculated using American (%pred US) or Canadian (%pred CAN) reference equations. Δ6MWD at 6 months were recorded. Clinical worsening was defined as either: development of right heart failure, hospital admission for PAH, referral for lung transplantation or initiation of prostanoids after oral therapy failed. Optimal 6-month differences in 6MWD to detect worsening were defined with receiver operating characteristics (ROC) analysis.

RESULTS

Progressors, i.e. patients with clinical worsening, and nonprogressors showed significant differences in Δ6MWD. The most clinically significant declines in 6MWD at 6 months were ≥35 m, ≥8%pred US and ≥6%pred CAN. ROC and Cox proportional hazard analyses showed equivalent results for 6MWD %pred and meters. Six-month declines in 6MWD predicted worsening with a high specificity (94%) but a low sensitivity (33%).

CONCLUSIONS

Early declines in 6MWD (within the first 6 months) predict future clinical worsening of PAH with high specificity. Δ6MWD may still be part of a comprehensive assessment of a patient's clinical status. However, given the poor sensitivity, a decline in 6MWD should be used with other clinical tools to make an appropriate assessment of the progression of PAH.

Macitentan for the treatment of pulmonary arterial hypertension

Macitentan is the most recently approved dual endothelin-receptor antagonist (ERA) for the treatment of symptomatic pulmonary arterial hypertension. Compared to other available ERAs, it demonstrates superior receptor-binding properties, with consequently improved tissue penetration, and a longer duration of action allowing for once-daily dosing. It has a favorable adverse-effect profile, with notably no demonstrable increase in the risk of hepatotoxicity or peripheral edema, but like other ERAs, it is potentially limited by significant anemia. Phase I data have demonstrated a favorable drug-drug interaction profile and no need for dose adjustment with hepatic and renal impairment. In the pivotal SERAPHIN study, treatment of symptomatic pulmonary arterial hypertension patients with macitentan led to statistically significant improvements in functional class, exercise tolerance, and hemodynamic parameters, in addition to a reduction in morbidity in an event-driven long-term trial.

Efficacy, safety and clinical pharmacology of macitentan in comparison to other endothelin receptor antagonists in the treatment of pulmonary arterial hypertension

INTRODUCTION

Macitentan is a novel dual endothelin receptor antagonist (ERA) showing sustained receptor occupancy. In vitro and in vivo animal studies have demonstrated its potency in antagonizing endothelin-induced disorders. A large morbidity/mortality study in patients with pulmonary arterial hypertension (PAH) taking macitentan has been completed recently.

AREAS COVERED

This drug evaluation reviews the efficacy, safety and clinical pharmacology of macitentan in the treatment of PAH.

EXPERT OPINION

The large Phase III study (SERAPHIN) tested macitentan in more than 700 PAH patients and has provided unique long-term outcome data for this ERA, not available for other members of this class. The effect on a composite clinically relevant morbidity/mortality end point was highly significant at a 10 mg/day dose. The safety profile of macitentan appears to be superior with respect to hepatic safety and edema/fluid retention than bosentan and ambrisentan, respectively, and is similar when considering decrease in hemoglobin concentration. The drug has a low propensity for drug-drug interactions and has one circulating pharmacologically active metabolite. The pharmacokinetics of macitentan in patients with renal or hepatic impairment does not require dose adjustments. Based on its characteristics, macitentan is an important addition to the therapeutic armamentarium in the long-term treatment of PAH. Its potential use in other disorders is under investigation.

Prostanoid therapy for pulmonary arterial hypertension: a meta-analysis of survival outcomes

BACKGROUND

Prostanoids have played an important role in the treatment of pulmonary arterial hypertension (PAH). However, whether prostanoid therapy provides a survival advantage is still not clear. The aim of this meta-analysis was to evaluate the efficacy and safety of prostanoids in PAH, focusing on the improvement in overall survival.

METHODS

Trials were identified from the Cochrane Library, EMBASE, and PUBMED databases. We calculated risk ratios (RR) for dichotomous data and weighted mean differences with 95 % confidence intervals (CI) for continuous data.

RESULTS

Fourteen trials with a total of 2,244 adult patients (1,189 patients in the prostanoid treatment group and 1,055 patients in the placebo group) were included in the meta-analysis. All-cause mortality rate in the control group was 4.17 %. In a 13.4-week follow-up, prostanoid treatment was associated with a 44 % reduction in mortality (RR 0.56; 95 % CI 0.35-0.88; P = 0.01).Subgroup analysis suggested that only treatment with intravenous prostanoids provided a survival benefit. Compared with placebo, prostanoids significantly reduced clinical worsening (RR 0.60; 95 % CI 0.46-0.80; P = 0.0003), increased the 6-min walk distance by 27.95 m, reduced mean pulmonary arterial pressure and pulmonary vascular resistance, and increased the cardiac index and mixed venous oxygen saturation. However, patients receiving prostanoid treatment showed a much higher incidence (RR 3.25; 95 % CI 2.07-5.10; P<0.00001) of withdrawal due to its adverse effects.

CONCLUSION

The results of this meta-analysis suggest that treatment with prostanoids improves the survival of patients with PAH.

From short-term benefits to long-term outcomes: the evolution of clinical trials in pulmonary arterial hypertension

Abstract Over the past 2 decades, major advances in our understanding of pulmonary arterial hypertension (PAH) have led to the development of new targeted therapeutics and management strategies that have provided benefits to patients with this devastating disease. Despite such improvements, no therapies are curative, and PAH remains a progressive disease associated with high morbidity and suboptimal survival in many patients. Clinical research in PAH is currently at a crossroads. To move forward, not only are new therapies needed, but novel approaches to clinical trial design are also required. Trials should be designed to assess the longer-term benefits of investigational therapies in what has become a chronic disease. Moreover, there is a need to consider moving away from short-term trials that use markers such as the 6-minute walk distance as a measure of exercise capacity as primary end points to longer-term, event-driven trials with composite end points made up of clinically relevant measures that better reflect the ultimate goals of reducing morbidity and mortality. A shift in trial design may also be useful in overcoming some of the muted results from recent pivotal phase III studies of combination therapy by allowing the potential of these regimens to be more comprehensively assessed.

Macitentan and morbidity and mortality in pulmonary arterial hypertension

BACKGROUND

Current therapies for pulmonary arterial hypertension have been adopted on the basis of short-term trials with exercise capacity as the primary end point. We assessed the efficacy of macitentan, a new dual endothelin-receptor antagonist, using a primary end point of morbidity and mortality in a long-term trial.

METHODS

We randomly assigned patients with symptomatic pulmonary arterial hypertension to receive placebo once daily, macitentan at a once-daily dose of 3 mg, or macitentan at a once-daily dose of 10 mg. Stable use of oral or inhaled therapy for pulmonary arterial hypertension, other than endothelin-receptor antagonists, was allowed at study entry. The primary end point was the time from the initiation of treatment to the first occurrence of a composite end point of death, atrial septostomy, lung transplantation, initiation of treatment with intravenous or subcutaneous prostanoids, or worsening of pulmonary arterial hypertension.

RESULTS

A total of 250 patients were randomly assigned to placebo, 250 to the 3-mg macitentan dose, and 242 to the 10-mg macitentan dose. The primary end point occurred in 46.4%, 38.0%, and 31.4% of the patients in these groups, respectively. The hazard ratio for the 3-mg macitentan dose as compared with placebo was 0.70 (97.5% confidence interval [CI], 0.52 to 0.96; P=0.01), and the hazard ratio for the 10-mg macitentan dose as compared with placebo was 0.55 (97.5% CI, 0.39 to 0.76; P<0.001). Worsening of pulmonary arterial hypertension was the most frequent primary end-point event. The effect of macitentan on this end point was observed regardless of whether the patient was receiving therapy for pulmonary arterial hypertension at baseline. Adverse events more frequently associated with macitentan than with placebo were headache, nasopharyngitis, and anemia.

CONCLUSIONS

Macitentan significantly reduced morbidity and mortality among patients with pulmonary arterial hypertension in this event-driven study. (Funded by Actelion Pharmaceuticals; SERAPHIN ClinicalTrials.gov number, NCT00660179.).

Riociguat for the treatment of pulmonary arterial hypertension

BACKGROUND

Riociguat, a soluble guanylate cyclase stimulator, has been shown in a phase 2 trial to be beneficial in the treatment of pulmonary arterial hypertension.

METHODS

In this phase 3, double-blind study, we randomly assigned 443 patients with symptomatic pulmonary arterial hypertension to receive placebo, riociguat in individually adjusted doses of up to 2.5 mg three times daily (2.5 mg-maximum group), or riociguat in individually adjusted doses that were capped at 1.5 mg three times daily (1.5 mg-maximum group). The 1.5 mg-maximum group was included for exploratory purposes, and the data from that group were analyzed descriptively. Patients who were receiving no other treatment for pulmonary arterial hypertension and patients who were receiving endothelin-receptor antagonists or (nonintravenous) prostanoids were eligible. The primary end point was the change from baseline to the end of week 12 in the distance walked in 6 minutes. Secondary end points included the change in pulmonary vascular resistance, N-terminal pro-brain natriuretic peptide (NT-proBNP) levels, World Health Organization (WHO) functional class, time to clinical worsening, score on the Borg dyspnea scale, quality-of-life variables, and safety.

RESULTS

By week 12, the 6-minute walk distance had increased by a mean of 30 m in the 2.5 mg-maximum group and had decreased by a mean of 6 m in the placebo group (least-squares mean difference, 36 m; 95% confidence interval, 20 to 52; P<0.001). Prespecified subgroup analyses showed that riociguat improved the 6-minute walk distance both in patients who were receiving no other treatment for the disease and in those who were receiving endothelin-receptor antagonists or prostanoids. There were significant improvements in pulmonary vascular resistance (P<0.001), NT-proBNP levels (P<0.001), WHO functional class (P=0.003), time to clinical worsening (P=0.005), and Borg dyspnea score (P=0.002). The most common serious adverse event in the placebo group and the 2.5 mg-maximum group was syncope (4% and 1%, respectively).

CONCLUSIONS

Riociguat significantly improved exercise capacity and secondary efficacy end points in patients with pulmonary arterial hypertension. (Funded by Bayer HealthCare; PATENT-1 and PATENT-2 ClinicalTrials.gov numbers, NCT00810693 and NCT00863681, respectively.).

Updating clinical endpoint definitions

The 6-Minute Walk Distance (6-MWD) has been the most utilized endpoint for judging the efficacy of pulmonary arterial hypertension (PAH) therapy in clinical trials conducted over the past two decades. Despite its simplicity, widespread use in recent trials and overall prognostic value, the 6-MWD has often been criticized over the past several years and pleas from several PAH experts have emerged from the literature to find alternative endpoints that would be more reliable in reflecting the pulmonary vascular resistance as well as cardiac status in PAH and their response to therapy. A meeting of PAH experts and representatives from regulatory agencies and pharmaceutical companies was convened in early 2012 to discuss the validity of current as well as emerging valuable endpoints. The current work represents the proceedings of the conference.

Mechanics and Function of the Pulmonary Vasculature: Implications for Pulmonary Vascular Disease and Right Ventricular Function

The relationship between cardiac function and the afterload against which the heart muscle must work to circulate blood throughout the pulmonary circulation is defined by a complex interaction between many coupled system parameters. These parameters range broadly and incorporate system effects originating primarily from three distinct locations: input power from the heart, hydraulic impedance from the large conduit pulmonary arteries, and hydraulic resistance from the more distal microcirculation. These organ systems are not independent, but rather, form a coupled system in which a change to any individual parameter affects all other system parameters. The result is a highly nonlinear system which requires not only detailed study of each specific component and the effect of disease on their specific function, but also requires study of the interconnected relationship between the microcirculation, the conduit arteries, and the heart in response to age and disease. Here, we investigate systems-level changes associated with pulmonary hypertensive disease progression in an effort to better understand this coupled relationship.