Long-term effects of inhaled treprostinil in patients with pulmonary arterial hypertension: the Treprostinil Sodium Inhalation Used in the Management of Pulmonary Arterial Hypertension (TRIUMPH) study open-label extension

Therapeutic Potential of Treprostinil Inhalation Powder for Patients with Pulmonary Arterial Hypertension: Evidence to Date

Pulmonary arterial hypertension (PAH) is a complex and incurable disease for which pulmonary vasodilators remain the core therapy. Of the three primary pathways that vasodilators target, the prostacyclin pathway was the earliest to be used and currently has the largest number of modalities for drug delivery. Inhaled treprostinil has been introduced as a treatment option in PAH and, more recently, pulmonary hypertension (PH) due to interstitial lung disease (PH-ILD), and the earlier nebulized form has been joined by a dry powder form allowing for more convenient use. In this review, we discuss inhaled treprostinil, focusing on the dry powder inhalation (DPI) formulation, and explore its dosing, applications, and evidence to support patient tolerance and acceptance. Recent trials underpinning the evidence for use of inhaled treprostinil and the most recent developments concerning the drug are discussed. Finally, the review looks briefly into premarket formulations of inhaled treprostinil and relevant early studies suggesting efficacy in PAH treatment.

Oral Treprostinil is Associated with Improved Survival in FREEDOM-EV and its Open-Label Extension

INTRODUCTION

In the event-driven FREEDOM-EV trial, oral treprostinil delayed clinical worsening in patients with pulmonary arterial hypertension (PAH). Open-label extension studies offer additional data about tolerability, efficacy, and survival, especially for those initially assigned placebo. The aim of the current study was to determine if oral treprostinil changed survival when considering the parent and extension study, if treprostinil provides functional benefits for participants initially assigned to placebo, and if the benefits observed for those treated with treprostinil were durable.

METHODS

Both active and placebo participants from FREEDOM-EV could enroll in the FREEDOM-EV open-label extension (OLE) study after experiencing an investigator-assessed clinical worsening event or after parent study closure. All participants in the OLE were offered open-label oral treprostinil. Previously assigned placebo participants titrated to maximally tolerated doses; previously assigned treprostinil participants continued dose titration. We repeated assessments including functional class and 6-min walk distance (6MWD) at 12-week intervals and measured N-terminal pro-brain natriuretic peptide (NT-proBNP) at week 48. Survival was estimated by Kaplan-Meier analysis, and we estimated hazard ratio (HR) using Cox proportional hazards.

RESULTS

Of 690 FREEDOM-EV participants, 470 enrolled in the OLE; vital status was available for 89% of initial Freedom-EV participants. When considering the combined parent and open-label data, initial assignment to oral treprostinil reduced mortality (HR 0.64, 95% confidence interval 0.46-0.91, p = 0.013); absolute risk reduction was 9%. Participants randomized to placebo who initiated oral treprostinil after clinical worsening and tolerated treatment through week 48 demonstrated favorable shifts in functional class (p < 0.0001), 6MWD improvements of + 84 m (p < 0.0001), and a reduction in NT-proBNP of - 778 pg/mL (p = 0.02), compared to OLE baseline. Modest trends toward benefit were measured for those initially assigned placebo who did not have clinical worsening, and 132/144 (92%) of treprostinil assigned participants without clinical worsening remained on drug at week 48 in the OLE study. Adverse events were consistent with FREEDOM-EV.

CONCLUSION

Initial treprostinil assignment improved survival in the entire data set; those who began treprostinil after a clinical worsening in the placebo arm and tolerated drug to week 48 enjoyed substantial functional gains.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT01560637.

Inhaled Pulmonary Vasodilators for the Treatment of Right Ventricular Failure in Cardio-Thoracic Surgery: Is One Better than the Others?

Right ventricular failure (RFV) is a potential complication following cardio-thoracic surgery, with an incidence ranging from 0.1% to 30%. The increase in pulmonary vascular resistance (PVR) is one of the main triggers of perioperative RVF. Inhaled pulmonary vasodilators (IPVs) can reduce PVR and improve right ventricular function with minimal systemic effects. This narrative review aims to assess the efficacy of inhaled nitric oxide and inhaled prostacyclins for the treatment of perioperative RVF. The literature, although statistically limited, supports the clinical similarity between them. However, it failed to demonstrate a clear benefit from the pre-emptive use of inhaled nitric oxide in patients undergoing left ventricular assist device implantation or early administration during heart-lung transplants. Additional concerns are related to cost safety and IPV use in pathologies associated with pulmonary venous congestion. The largest ongoing randomized controlled trial on adults (INSPIRE-FLO) is addressing whether inhaled Epoprostenol and inhaled nitric oxide are similar in preventing RVF after heart transplants and left ventricular assist device placement, and whether they are similar in preventing primary graft dysfunction after lung transplants. The preliminary analysis supports their equivalence. Several key points may be achieved by the present narrative review. When RVF occurs in the setting of elevated PVR, IPV should be the preferred initial treatment and they should be preventively used in patients at high risk of postoperative RVF. If severe refractory postoperative RVF occurs, IPVs should be combined with complementary pharmacology (inotropes and inodilators). If unsuccessful, right ventricular mechanical support should be established.

Tyvaso DPI: Drug-device characteristics and patient clinical considerations

Tyvaso DPI is a drug-device combination therapy comprised of a small, portable, reusable, breath-powered, dry powder inhaler (DPI) for the delivery of treprostinil. It is approved for the treatment of pulmonary arterial hypertension and pulmonary hypertension associated with interstitial lung disease. Tyvaso DPI utilizes single-use prefilled cartridges to ensure proper dosing. Unlike nebulizer devices, administration of Tyvaso DPI is passive and does not require coordination with the device. The low-flow rate design results in targeted delivery to the peripheral lungs due to minimal drug loss from impaction in the oropharynx. The inert fumaryl diketopiperazine (FDKP) excipient forms microparticles that carry treprostinil into the airways, with a high fraction of the particles in the respirable range. In a clinical study in patients with pulmonary arterial hypertension, Tyvaso DPI had similar exposure and pharmacokinetics, low incidence of adverse events, and high patient satisfaction compared with nebulized treprostinil solution. Tyvaso DPI may be considered as a first prostacyclin agent or for those that do not tolerate other prostacyclin formulations, patients with pulmonary comorbidities, patients with mixed Group 1 and Group 3 pulmonary hypertension, or those that prefer an active lifestyle and need a portable, non-invasive treatment. Tyvaso DPI is a patient-preferred, maintenance-free, safe delivery option that may improve patient compliance and adherence.

Pulmonary hypertension inhaled therapies: An updated review

Treatments of pulmonary hypertension (PH) continue to evolve with approval of new therapies. The currently FDA approved inhaled PH therapies include inhaled iloprost for group 1 pulmonary arterial hypertension (PAH), inhaled treprostinil solution and treprostinil dry powder inhaler for both group 1 PAH and group 3 PH associated with interstitial lung disease (PH-ILD). Inhaled treprostinil was recently approved for group 3 PH-ILD based on the results of INCREASE trial and the newer formulation of treprostinil dry powder that comes with a new inhaler was recently approved for both group 1 PAH and group 3 PH-ILD based on BREEZE study. The pipeline for inhaled PH therapies includes several promising molecules that can enrich the current PH therapeutic era and mitigate several systemic side effects by directly delivering the drug to the target organ. In this review article we summarize the evidence for the currently approved inhaled PAH/PH therapies, discuss the available inhalation devices, present a roadmap for successful treatment strategy, and present several inhaled PAH/PH therapies in the pipeline.

Pathophysiology and pathogenic mechanisms of pulmonary hypertension: role of membrane receptors, ion channels, and Ca2+ signaling

The pulmonary circulation is a low-resistance, low-pressure, and high-compliance system that allows the lungs to receive the entire cardiac output. Pulmonary arterial pressure is a function of cardiac output and pulmonary vascular resistance, and pulmonary vascular resistance is inversely proportional to the fourth power of the intraluminal radius of the pulmonary artery. Therefore, a very small decrease of the pulmonary vascular lumen diameter results in a significant increase in pulmonary vascular resistance and pulmonary arterial pressure. Pulmonary arterial hypertension is a fatal and progressive disease with poor prognosis. Regardless of the initial pathogenic triggers, sustained pulmonary vasoconstriction, concentric vascular remodeling, occlusive intimal lesions, in situ thrombosis, and vascular wall stiffening are the major and direct causes for elevated pulmonary vascular resistance in patients with pulmonary arterial hypertension and other forms of precapillary pulmonary hypertension. In this review, we aim to discuss the basic principles and physiological mechanisms involved in the regulation of lung vascular hemodynamics and pulmonary vascular function, the changes in the pulmonary vasculature that contribute to the increased vascular resistance and arterial pressure, and the pathogenic mechanisms involved in the development and progression of pulmonary hypertension. We focus on reviewing the pathogenic roles of membrane receptors, ion channels, and intracellular Ca2+ signaling in pulmonary vascular smooth muscle cells in the development and progression of pulmonary hypertension.

Efficacy, safety, and pharmacokinetics of inhaled treprostinil in Japanese patients with pulmonary arterial hypertension

Treprostinil is a chemically stable analog of prostacyclin, and inhaled treprostinil was developed to deliver the effects directly to the pulmonary vasculature while minimizing systemic side effects. The objective of the study was to evaluate the efficacy on hemodynamics and exercise capacity, safety, and pharmacokinetics (PK) of inhaled treprostinil in Japanese patients with pulmonary arterial hypertension (PAH). Inhaled treprostinil was administered at three breaths (18 μg)/session four times daily, and the dose was gradually increased to a maximum of nine breaths (54 μg)/session. Endpoints included change in pulmonary vascular resistance index (PVRI) as primary, other efficacy parameters, safety, and PK. Seventeen PAH patients, the majority of whom (76.5%) had been receiving both an endothelin receptor antagonist (ERA) and a phosphodiesterase type-5 (PDE5) inhibitor/soluble guanylate cyclase (sGC) stimulator, received inhaled treprostinil. At Week 12, PVRI statistically decreased by -39.4 ± 25.5% (95% confidence interval: -52.6 to -26.3). The most frequently reported adverse events related to treprostinil were headache, cough, throat irritation, and hot flush. Regarding PK, there were no notable differences in the geometric mean C _max and AUC_last between Japanese and non-Japanese patients. Treatment with inhaled treprostinil using the dosing regimen approved in the United States resulted in significant improvement in hemodynamics, exercise capacity, and symptoms with a favorable tolerability and safety profile in Japanese patients. Inhaled treprostinil could be a valuable therapeutic option for Japanese patients with PAH, including those receiving a combination therapy with an ERA and a PDE5 inhibitor/sGC stimulator. Trial registration: JAPIC Clinical Trials Information [JapicCTI-194651].

Management of pregnant patients with pulmonary arterial hypertension

Pregnant individuals with pulmonary arterial hypertension (PAH) have significantly high risks of maternal and perinatal mortality. Profound changes in plasma volume, cardiac output and systemic vascular resistance can all increase the strain being placed on the right ventricle, leading to heart failure and cardiovascular collapse. Given the complex network of opposing physiological changes, strict contraception and reduction of hemodynamic fluctuations during pregnancy are important methods of minimizing the risk of maternal mortality and improving the outcomes following pregnancy. In this review, we discuss the recent research progress into pre-conception management and the various therapeutic strategies for pregnant individuals with PAH.

Long-Term Safety, Tolerability and Survival in Patients with Pulmonary Arterial Hypertension Treated with Macitentan: Results from the SERAPHIN Open-Label Extension

Introduction

In SERAPHIN, a long-term, event-driven, double-blind randomised controlled trial in pulmonary arterial hypertension (PAH), macitentan 10 mg significantly reduced the risk of morbidity/mortality compared with placebo. Its open-label extension study (SERAPHIN OL) further assessed long-term safety and tolerability of macitentan 10 mg in PAH patients.

Methods

Patients in SERAPHIN who completed the double-blind treatment period or experienced a morbidity event during the study could enter SERAPHIN OL. Patients received macitentan 10 mg once daily, and safety and survival were assessed until end of treatment (+ 28 days). Two overlapping sets were analysed for safety: (1) all patients in SERAPHIN OL (OL safety set); (2) patients randomised to macitentan 10 mg in SERAPHIN (long-term safety/survival set). Survival was evaluated as an exploratory endpoint in the latter set.

Results

Of 742 patients randomised in SERAPHIN, 550 (74.1%) entered SERAPHIN OL (OL safety set); 242 patients were randomised to macitentan 10 mg in SERAPHIN (long-term safety/survival set). Median (min, max) exposure to macitentan 10 mg was 40.1 (0.1, 130.5) months (2074.7 patient-years; OL safety set) and 54.7 (0.1, 141.3) months (1151.0 patient-years; long-term safety/survival set). Safety in both analysis sets was comparable to the known safety profile of macitentan. Kaplan-Meier survival estimates (95% CI) at 1, 5, 7 and 9 years were 95.0% (91.3, 97.1), 73.3% (66.6, 78.9), 62.6% (54.6, 69.6) and 52.7% (43.6, 61.0), respectively (long-term safety/survival set; median follow-up: 5.9 years).

Conclusions

This analysis provides the longest follow-up for safety and survival published to date for any PAH therapy. The safety profile of macitentan 10 mg over this extensive treatment period was in line with that observed in SERAPHIN. As the majority of patients were receiving other PAH therapy at macitentan initiation, our study provides additional insight into the long-term safety of macitentan, including as part of combination therapy.

Trial Registration

ClinicalTrials.gov Identifiers: NCT00660179 and NCT00667823.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-022-02199-x.

Indian Guidelines on Nebulization Therapy

Inhalational therapy, today, happens to be the mainstay of treatment in obstructive airway diseases (OADs), such as asthma, chronic obstructive pulmonary disease (COPD), and is also in the present, used in a variety of other pulmonary and even non-pulmonary disorders. Hand-held inhalation devices may often be difficult to use, particularly for children, elderly, debilitated or distressed patients. Nebulization therapy emerges as a good option in these cases besides being useful in the home care, emergency room and critical care settings. With so many advancements taking place in nebulizer technology; availability of a plethora of drug formulations for its use, and the widening scope of this therapy; medical practitioners, respiratory therapists, and other health care personnel face the challenge of choosing appropriate inhalation devices and drug formulations, besides their rational application and use in different clinical situations. Adequate maintenance of nebulizer equipment including their disinfection and storage are the other relevant issues requiring guidance. Injudicious and improper use of nebulizers and their poor maintenance can sometimes lead to serious health hazards, nosocomial infections, transmission of infection, and other adverse outcomes. Thus, it is imperative to have a proper national guideline on nebulization practices to bridge the knowledge gaps amongst various health care personnel involved in this practice. It will also serve as an educational and scientific resource for healthcare professionals, as well as promote future research by identifying neglected and ignored areas in this field. Such comprehensive guidelines on this subject have not been available in the country and the only available proper international guidelines were released in 1997 which have not been updated for a noticeably long period of over two decades, though many changes and advancements have taken place in this technology in the recent past. Much of nebulization practices in the present may not be evidence-based and even some of these, the way they are currently used, may be ineffective or even harmful. Recognizing the knowledge deficit and paucity of guidelines on the usage of nebulizers in various settings such as inpatient, out-patient, emergency room, critical care, and domiciliary use in India in a wide variety of indications to standardize nebulization practices and to address many other related issues; National College of Chest Physicians (India), commissioned a National task force consisting of eminent experts in the field of Pulmonary Medicine from different backgrounds and different parts of the country to review the available evidence from the medical literature on the scientific principles and clinical practices of nebulization therapy and to formulate evidence-based guidelines on it. The guideline is based on all possible literature that could be explored with the best available evidence and incorporating expert opinions. To support the guideline with high-quality evidence, a systematic search of the electronic databases was performed to identify the relevant studies, position papers, consensus reports, and recommendations published. Rating of the level of the quality of evidence and the strength of recommendation was done using the GRADE system. Six topics were identified, each given to one group of experts comprising of advisors, chairpersons, convenor and members, and such six groups (A-F) were formed and the consensus recommendations of each group was included as a section in the guidelines (Sections I to VI). The topics included were: A. Introduction, basic principles and technical aspects of nebulization, types of equipment, their choice, use, and maintenance B. Nebulization therapy in obstructive airway diseases C. Nebulization therapy in the intensive care unit D. Use of various drugs (other than bronchodilators and inhaled corticosteroids) by nebulized route and miscellaneous uses of nebulization therapy E. Domiciliary/Home/Maintenance nebulization therapy; public & health care workers education, and F. Nebulization therapy in COVID-19 pandemic and in patients of other contagious viral respiratory infections (included later considering the crisis created due to COVID-19 pandemic). Various issues in different sections have been discussed in the form of questions, followed by point-wise evidence statements based on the existing knowledge, and recommendations have been formulated.

Long-Term Survival, Safety and Tolerability with Selexipag in Patients with Pulmonary Arterial Hypertension: Results from GRIPHON and its Open-Label Extension

INTRODUCTION

In the event-driven GRIPHON randomised-controlled trial, the oral prostacyclin receptor agonist selexipag significantly reduced the risk of disease progression (composite primary endpoint of morbidity/mortality), compared with placebo, in patients with pulmonary arterial hypertension (PAH). The ongoing open-label extension study (GRIPHON OL) collects further data on long-term safety, tolerability, and survival of PAH patients treated with selexipag.

METHODS

Patients randomised to selexipag or placebo in GRIPHON could enter GRIPHON OL either after experiencing a morbidity event during double-blind treatment or at the end of the study. Patients were followed for adverse events (AE) and survival from selexipag initiation up to 3 days and 30 days after end of treatment, respectively. Data are presented up to a cut-off date of 1 September 2019.

RESULTS

Overall, 953 patients in GRIPHON and GRIPHON OL were treated with selexipag. At the time of selexipag initiation, 81.2% of patients were receiving background PAH therapy. Median (min, max) exposure to selexipag was 31.7 months (0, 106), corresponding to a total of 3054.4 patient-years. The most frequently reported AEs were related to known prostacyclin-related effects or underlying disease. There were 305 (32.0%) patients who experienced an AE leading to treatment discontinuation. Survival during GRIPHON and GRIPHON OL was assessed for the 574 patients randomised to selexipag in GRIPHON. Kaplan-Meier survival estimates (95%CI) at 1, 3, 5 and 7 years were 92.0% (89.4, 94.0), 79.3% (75.4, 82.6), 71.2% (66.5, 75.3) and 63.0% (57.4, 68.1), respectively.

CONCLUSIONS

These results provide the longest follow-up period published to date for a PAH therapy. The safety profile of selexipag over this extended treatment period was consistent with that observed in GRIPHON. A large proportion of the population was receiving background therapy at selexipag initiation, providing further insight into the long-term safety of selexipag as part of a combination therapy regimen.

TRIAL REGISTRATION

ClinicalTrials.gov Identifiers: NCT01106014 and NCT01112306.

Survival and drug persistence in patients receiving inhaled treprostinil at doses greater than 54 µg (nine breaths) four times daily

Treprostinil is a prostacyclin approved for the treatment of pulmonary arterial hypertension. Commercial data sets indicate that approximately 20-25% of patients are prescribed a higher dose than the maximum recommended dosage of nine breaths per treatment session (bps) (54 μg), four times a day (QID) and numerous studies have demonstrated the safety of doses >9 bps QID. This phase 4, retrospective analysis of specialty pharmacy records assessed the effects of inhaled treprostinil at doses >9 bps QID. Patients receiving inhaled treprostinil between September 2009 and June 2018 were included, and a random sampling of 5000 patients was selected for further analysis. Subjects were grouped based on the highest dose reached for ≥2 months within a rolling six-month window and were followed for up to three years. Of the total of 5000 patients analyzed, 28.5% received >9 bps QID. Survival rates were significantly higher in the >9 bps QID dosing group for years one, two, and three (P < 0.001). The time to transition to parenteral therapy was significantly longer for those at doses >9 bps (17.5 months) compared to doses ≤9 bps (9.5 moths; P < 0.0001). Drug persistence was also significantly higher for those taking >9 bps at years 1, 2, and 3 (P < 0.0001). Patients receiving inhaled treprostinil at doses >9 bps QID had a higher rate of survival and drug persistence over a three-year period, suggesting that higher doses may provide clinically relevant benefits while remaining tolerable.

[Characteristics of patients with connective tissue disease-associated pulmonary arterial hypertension treated with prostanoids: A multicenter retrospective study]

INTRODUCTION

Pulmonary arterial hypertension (PAH) is a severe complication of connective tissue disease (CTD). Data on use of prostanoids in this particular subset of patients are lacking. We aimed to describe the characteristics of patients with PAH-CTD treated with prostanoids and the outcomes under treatment.

METHODS

In this multicenter retrospective study, all patients treated with prostanoids since 2006 were included. Data on PAH and CTD were collected at the time of prostanoid introduction and under treatment.

RESULTS

Twenty-one patients were included, of whom 20 (95%) had limited cutaneous systemic sclerosis. Nineteen patients were treated with oral monotherapy or combination before addition of prostanoid. Treprostinil was the most used molecule (57% of patients). At the time of prostanoid introduction, 90% of patients were considered at high risk for death. Among patients who had right heart catheterization during follow-up, there was no significant difference in haemodynamics. No extrarespiratory worsening of the CTD was reported. The 1-year survival under prostanoid was 62%. In univariate analysis, NYHA functional class was associated with survival under treatment.

CONCLUSION

This study provides original data on use of prostanoids in a cohort consisting mainly of systemic sclerosis. It underlines the difficulty to achieve a standardized assessment in this subset of patients. Safety profile was comparable with data reported in idiopathic PAH.

Inhaled pulmonary vasodilators: a narrative review

Pulmonary hypertension (PH) is a severe disease that affects people of all ages. It can occur as an idiopathic disorder at birth or as part of a variety of cardiovascular and pulmonary disorders. Inhaled pulmonary vasodilators (IPV) can reduce pulmonary vascular resistance (PVR) and improve RV function with minimal systemic effects. IPV includes inhaled nitric oxide (iNO), inhaled aerosolized prostacyclin, or analogs, including epoprostenol, iloprost, treprostinil, and other vasodilators. In addition to pulmonary vasodilating effects, IPV can also be used to improve oxygenation, reduce inflammation, and protect cell. Off-label use of IPV is common in daily clinical practice. However, evidence supporting the inhalational administration of these medications is limited, inconclusive, and controversial regarding their safety and efficacy. We conducted a search for relevant papers published up to May 2020 in four databases: PubMed, Google Scholar, EMBASE and Web of Science. This review demonstrates that the clinical using and updated evidence of IPV. iNO is widely used in neonates, pediatrics, and adults with different cardiopulmonary diseases. The limitations of iNO include high cost, flat dose-response, risk of significant rebound PH after withdrawal, and the requirement of complex technology for monitoring. The literature suggests that inhaled aerosolized epoprostenol, iloprost, treprostinil and others such as milrinone and levosimendan may be similar to iNO. More research of IPV is needed to determine acceptable inclusion criteria, long-term outcomes, and management strategies including time, dose, and duration.

Impact of inhaled treprostinil on risk stratification with noninvasive parameters: a post hoc analysis of the TRIUMPH and BEAT studies

The 2015 European Society of Cardiology/European Respiratory Society treatment guidelines recommend frequent risk assessment in pulmonary arterial hypertension utilizing risk variables. Our objectives were: (1) to investigate the impact of inhaled treprostinil on risk stratification using the French noninvasive approach and REVEAL 2.0, and (2) to analyze the prognostic utility of both risk stratification methods in the predominantly New York Heart Association/World Health Organization functional class III/IV cohorts of TRIUMPH and BEAT. A post hoc analysis was performed to assess risk at baseline and follow-up at Week 12 in the TRIUMPH cohort (n = 148) and at Week 16, 21, and 30 in the inhaled treprostinil naïve placebo BEAT cohort (n = 73). Overall survival, clinical worsening-free survival, and pulmonary arterial hypertension-related hospitalization-free survival were all assessed in the pooled TRIUMPH and inhaled treprostinil naïve placebo BEAT cohorts based on risk group/strata at Week 12/16 follow-up. Inhaled treprostinil improved REVEAL 2.0 risk stratum (OR: 2.38, 95% CI: 1.09–5.19, p = 0.0298) and REVEAL 2.0 score (p = 0.0008) compared to placebo in the TRIUMPH cohort at Week 12. REVEAL 2.0 risk stratum and the number of low-risk criteria by the French approach improved at Weeks 16, 21, and 30 in the inhaled treprostinil naïve placebo BEAT cohort. Combining cohorts, REVEAL 2.0 risk stratification at follow-up was prognostic for clinical worsening-free, pulmonary arterial hypertension hospitalization-free, and overall survival, whereas the number of low-risk criteria was not. These post-hoc pooled analyses suggest inhaled treprostinil improves risk status and indicates that the REVEAL 2.0 calculator may be more suitable than the French noninvasive method for evaluating short-term clinical change in the New York Heart Association/World Health Organization functional class III/IV population.

Pharmacokinetics and tolerability of LIQ861, a novel dry-powder formulation of treprostinil

A dry-powder inhaled formulation of treprostinil (LIQ861) produced using PRINT® technology offers a substantial advantage over current nebulized therapy. Treprostinil is a synthetic prostacyclin analogue that is currently approved for inhalation administration to patients with pulmonary arterial hypertension via nebulized Tyvaso® inhalation solution. LTI-101 was a phase 1, placebo-controlled, double-blind, randomized, single-center study that evaluated the ascending single-dose pharmacokinetics of LIQ861 in healthy subjects. Six sequential, escalating doses (25, 50, 75, 100, 125, and 150 mcg) were studied to investigate treprostinil exposure from LIQ861 inhalation. Subjects (n = 57) were randomly assigned in a 3:1 ratio to receive a single dose of either LIQ861 (n = 43) or placebo (n = 14); 56 subjects completed all protocol-defined assessments. Following single-dose administration, treprostinil exposure from LIQ861 increased proportionally across the dose range studied, and the pharmacokinetics profile of treprostinil administered as LIQ861 was similar to prior reports of inhaled treprostinil. All doses of LIQ861 were generally well-tolerated with no deaths, serious adverse events, or dose-limiting toxicities. The most frequently reported treatment-emergent adverse events related to study drug administration were coughing and throat irritation, which are common to dry-powder formulations. Treatment-related treatment-emergent adverse events were reported more frequently at higher dose levels; however, all were assessed as mild in severity. We conclude that the pharmacokinetics profile of treprostinil using a dry-powder inhaled formulation increased in proportion to dose as anticipated and was similar to earlier reports of inhaled, nebulized treprostinil (Tyvaso®). Based on these results, a phase 3 study (INSPIRE; Clinicaltrials.gov Identifier NCT03399604) evaluating the long-term safety and tolerability of LIQ861 in patients with pulmonary arterial hypertension was initiated.

Follow-Up Functional Class and 6-Minute Walk Distance Identify Long-Term Survival in Pulmonary Arterial Hypertension

PURPOSE

Guidelines recommend specific treatment goals for pulmonary arterial hypertension (PAH) patients: functional class I or II, 6-min walk distance (6MWD) ≥ 380 to 440 m, normal natriuretic peptide levels, and normal right-sided invasive hemodynamics. Only observational registry data support this recommendation. Our aim was to test these goals in a large group 1 PAH cohort against long-term survival.

METHODS

We analyzed the PHIRST and TRIUMPH populations (n = 563, age 53.5 ± 14.7 years, female sex 79%). The predictor variables were the treatment goals measured at the end of the placebo-controlled phase (16 and 12 weeks, respectively). The primary outcome was all-cause mortality at the end of follow-up during the open-label extension phase.

RESULTS

There were 73 deaths during median follow of 1072 days (range 27 to 2177). Patients who achieved a functional class I or II had better survival. Both a 6MWD ≥ 380 m and ≥ 440 m were associated with lower mortality, but survival was better in patients able to walk ≥ 440 m. The best long-term survival was achieved with functional class I or II and 6MWD ≥ 440 m. In a subset of the population, cardiac index > 2.5 L/min/m² was weakly associated with better survival.

CONCLUSION

WHO functional class I or II, 6MWD ≥ 440 m and CI > 2.5 L/min/m² measured 12-16 weeks after the introduction of PAH-targeted therapy are associated with better long-term survival in PAH. Best survival is observed by reaching both the functional class and the 6MWD goals.

The prostacyclin analogue treprostinil in the treatment of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a rare but life-threatening disease that progresses rapidly and is currently without a cure. Pharmacological treatments aim to slow down disease progression and to reduce symptoms by targeting the prostacyclin, the endothelin or the nitric oxide pathway. Drugs targeting the prostacyclin pathway have been shown to be favourable for PAH patients by causing vasodilatative, anti-proliferative as well as anti-inflammatory effects, but tend to be underused, partially due to adverse effects and difficulties associated with their intravenous administration. Treprostinil, a stable prostacyclin analogue, was FDA-approved in 2002 to improve exercise capacity in PAH patients and is available in intravenous, subcutaneous, inhaled and oral form. The four different possible ways of administration, a long half-life and its stability at room temperature give treprostinil an advantage over epoprostenol, iloprost and selexipag, the three other FDA-approved drugs targeting the prostacyclin pathway. In clinical trials, treprostinil improved exercise capacity, quality of life (QOL), functional class and clinical status. While the different forms of treprostinil lead to specific complications, its general adverse effects are dizziness, nausea, pain in the jaw and extremities, diarrhoea, flushing and headache. This MiniReview will assess the benefits and drawbacks of treprostinil in the treatment of PAH by examining its specific mechanism of action and pharmacological properties, such as pharmacokinetics, pharmacodynamics, adverse effects and interactions. In addition, we will analyse and discuss results from different clinical trials, comparing treprostinil's four different forms to each other as well as to other drugs targeting the prostacyclin pathway.

The Role of Noninvasive Endpoints in Predicting Long-Term Outcomes in Pulmonary Arterial Hypertension

Background

Until recently, many clinical trials in patients with pulmonary arterial hypertension (PAH) evaluated exercise capacity with 6-minute walk distance (6MWD) as the primary endpoint. Common secondary endpoints include PAH functional class (FC), which assesses symptoms, and either brain natriuretic peptide (BNP) or the inactive N-terminal cleavage product of its prohormone (NT-proBNP), which assesses cardiac function.

Objective

Examine the relationships among 6MWD, FC, and BNP/NT-proBNP measured at baseline or follow-up with long-term outcomes in PAH studies.

Methods

Relevant literature from January 1990 to April 2018 were obtained by searching PubMed, Embase, and Cochrane. Articles in English reporting on associations between 6MWD, FC, or BNP/NT-proBNP and outcomes in PAH were identified. Each endpoint was evaluated individually. Prespecified inclusion and exclusion criteria were applied at level 1 (titles/abstracts) and level 2 (full-text review).

Results

The database search yielded 836 unique records; 65 full-text articles were reviewed. Twenty-five studies were eligible for inclusion. Findings supported the importance of measuring PAH noninvasive endpoints in predicting long-term outcomes. Patients with shorter or decreased 6MWD, poor (III/IV) or declining FC (e.g., from II to III), or elevated or increasing BNP/NT-proBNP had a higher risk of death and costly events (e.g., hospitalization, lung transplant). FC also predicted health care resource utilization and costs. Collectively, these endpoints establish risk groups that predict likelihood of complications from PAH or death.

Conclusion

Assessment of 6MWD, FC, and BNP/NT-proBNP provides low-cost, efficient, and noninvasive means of predicting long-term health and economic outcomes in patients with PAH.

Bronchodilation induced by PGE2 is impaired in Group III pulmonary hypertension

BACKGROUND AND PURPOSE

In patients with pulmonary hypertension (PH) associated with lung disease and/or hypoxia (Group III), decreased pulmonary vascular tone and tissue hypoxia is therapeutically beneficial. PGE₂ and PGI₂ induce potent relaxation of human bronchi from non-PH (control) patients via EP₄ and IP receptors, respectively. However, the effects of PGE₂ /PGI₂ and their mimetics on human bronchi from PH patients are unknown. Here, we have compared relaxant effects of several PGI₂ -mimetics approved for treating PH Group I with several PGE₂ -mimetics, in bronchial preparations derived from PH Group III and control patients.

EXPERIMENTAL APPROACH

Relaxation of bronchial muscle was assessed in samples isolated from control and PH Group III patients. Expression of prostanoid receptors was analysed by western blot and real-time PCR, and endogenous PGE₂ , PGI₂ , and cAMP levels were determined by ELISA.

KEY RESULTS

Maximal relaxations induced by different EP₄ receptor agonists (PGE₂ , L-902688, and ONO-AE1-329) were decreased in human bronchi from PH patients, compared with controls. However, maximal relaxations produced by PGI₂ -mimetics (iloprost, treprostinil, and beraprost) were similar for both groups of patients. Both EP₄ and IP receptor protein and mRNA expressions were significantly lower in human bronchi from PH patients. cAMP levels significantly correlated with PGI₂ but not with PGE₂ levels.

CONCLUSION AND IMPLICATIONS

The PGI₂ -mimetics retained maximal bronchodilation in PH Group III patients, whereas bronchodilation induced by EP₄ receptor agonists was decreased. Restoration of EP₄ receptor expression in airways of PH Group III patients with respiratory diseases could bring additional therapeutic benefit.

Phosphodiesterase 5 inhibitors for pulmonary hypertension

BACKGROUND

Pulmonary hypertension (PH) comprises a group of complex and heterogenous conditions, characterised by elevated pulmonary artery pressure, and which left untreated leads to right-heart failure and death. PH includes World Health Organisation (WHO) Group 1 pulmonary arterial hypertension (PAH); Group 2 consists of PH due to left-heart disease (PH-LHD); Group 3 comprises PH as a result of lung diseases or hypoxia, or both; Group 4 includes PH due to chronic thromboembolic occlusion of pulmonary vasculature (CTEPH), and Group 5 consists of cases of PH due to unclear and/or multifactorial mechanisms including haematological, systemic, or metabolic disorders. Phosphodiesterase type 5 (PDE5) inhibitors increase vasodilation and inhibit proliferation.

OBJECTIVES

To determine the efficacy of PDE5 inhibitors for pulmonary hypertension in adults and children.

SEARCH METHODS

We performed searches of CENTRAL, MEDLINE, Embase, CINAHL, and Web of Science up to 26 September 2018. We handsearched review articles, clinical trial registries, and reference lists of retrieved articles.

SELECTION CRITERIA

We included randomised controlled trials that compared any PDE5 inhibitor versus placebo, or any other PAH disease-specific therapies, for at least 12 weeks. We include separate analyses for each PH group.

DATA COLLECTION AND ANALYSIS

We imported studies identified by the search into a reference manager database. We retrieved the full-text versions of relevant studies, and two review authors independently extracted data. Primary outcomes were: change in WHO functional class, six-minute walk distance (6MWD), and mortality. Secondary outcomes were haemodynamic parameters, quality of life/health status, dyspnoea, clinical worsening (hospitalisation/intervention), and adverse events. When appropriate, we performed meta-analyses and subgroup analyses by severity of lung function, connective tissue disease diagnosis, and radiological pattern of fibrosis. We assessed the evidence using the GRADE approach and created 'Summary of findings' tables.

MAIN RESULTS

We included 36 studies with 2999 participants (with pulmonary hypertension from all causes) in the final review. Trials were conducted for 14 weeks on average, with some as long as 12 months. Two trials specifically included children.Nineteen trials included group 1 PAH participants. PAH participants treated with PDE5 inhibitors were more likely to improve their WHO functional class (odds ratio (OR) 8.59, 95% confidence interval (CI) 3.95 to 18.72; 4 trials, 282 participants), to walk 48 metres further in 6MWD (95% CI 40 to 56; 8 trials, 880 participants), and were 22% less likely to die over a mean duration of 14 weeks (95% CI 0.07 to 0.68; 8 trials, 1119 participants) compared to placebo (high-certainty evidence). The number needed to treat to prevent one additional death was 32 participants. There was an increased risk of adverse events with PDE5 inhibitors, especially headache (OR 1.97, 95% CI 1.33 to 2.92; 5 trials, 848 participants), gastrointestinal upset (OR 1.63, 95% CI 1.07 to 2.48; 5 trials, 848 participants), flushing (OR 4.12, 95% CI 1.83 to 9.26; 3 trials, 748 participants), and muscle aches and joint pains (OR 2.52, 95% CI 1.59 to 3.99; 4 trials, 792 participants).Data comparing PDE5 inhibitors to placebo whilst on other PAH-specific therapy were limited by the small number of included trials. Those PAH participants on PDE5 inhibitors plus combination therapy walked 19.66 metres further in six minutes (95% CI 9 to 30; 4 trials, 509 participants) compared to placebo (moderate-certainty evidence). There were limited trials comparing PDE5 inhibitors directly with other PAH-specific therapy (endothelin receptor antagonists (ERAs)). Those on PDE5 inhibitors walked 49 metres further than on ERAs (95% CI 4 to 95; 2 trials, 36 participants) (low-certainty evidence). There was no evidence of a difference in WHO functional class or mortality across both treatments.Five trials compared PDE5 inhibitors to placebo in PH secondary to left-heart disease (PH-LHD). The quality of data were low due to imprecision and inconsistency across trials. In those with PH-LHD there were reduced odds of an improvement in WHO functional class using PDE5 inhibitors compared to placebo (OR 0.53, 95% CI 0.32 to 0.87; 3 trials, 285 participants), and those using PDE5 inhibitors walked 34 metres further compared to placebo (95% CI 23 to 46; 3 trials, 284 participants). There was no evidence of a difference in mortality. Five trials compared PDE5 inhibitors to placebo in PH secondary to lung disease/hypoxia, mostly in COPD. Data were of low quality due to imprecision of effect and inconsistency across trials. There was a small improvement of 27 metres in 6MWD using PDE5 inhibitors compared to placebo in those with PH due to lung disease. There was no evidence of worsening hypoxia using PDE5 inhibitors, although data were limited. Three studies compared PDE5 inhibitors to placebo or other PAH-specific therapy in chronic thromboembolic disease. There was no significant difference in any outcomes. Data quality was low due to imprecision of effect and heterogeneity across trials.

AUTHORS' CONCLUSIONS

PDE5 inhibitors appear to have clear beneficial effects in group 1 PAH. Sildenafil, tadalafil and vardenafil are all efficacious in this clinical setting, and clinicians should consider the side-effect profile for each individual when choosing which PDE5 inhibitor to prescribe.While there appears to be some benefit for the use of PDE5 inhibitors in PH-left-heart disease, it is not clear based on the mostly small, short-term studies, which type of left-heart disease stands to benefit. These data suggest possible harm in valvular heart disease. There is no clear benefit for PDE5 inhibitors in pulmonary hypertension secondary to lung disease or chronic thromboembolic disease. Further research is required into the mechanisms of pulmonary hypertension secondary to left-heart disease, and cautious consideration of which subset of these patients may benefit from PDE5 inhibitors. Future trials in PH-LHD should be sufficiently powered, with long-term follow-up, and should include invasive haemodynamic data, WHO functional class, six-minute walk distance, and clinical worsening.

Inhalation of repurposed drugs to treat pulmonary hypertension

Pulmonary arterial hypertension (PAH) is a rare, but severe and life-threatening disease characterized by vasoconstriction and remodeling of the pulmonary arterioles, leading to progressive increase in pulmonary vascular resistance and ultimately to right-heart failure. In the last two decades, significant progress in treatment of PAH has been made, with currently 12 drugs approved for targeted therapy. Among these, the stable prostacyclin analogues iloprost and treprostinil have been repurposed for inhalation. The paper highlights the development of the two drugs emphasizing the rationale and advantages of the inhalative approach. Despite substantial advances in the specific, mainly vasodilatory PAH therapy, disease progression is mostly inevitable and mortality remains unacceptably high. Thus, introduction of new drugs targeting the cancer-like remodeling of the diseased pulmonary arteries is urgently needed. Inhalation offers pulmonary selectivity and will hopefully pioneer the repurposing of novel highly potent drugs for effective aerosol therapy of PAH.

Tolerability and clinical efficacy of inhaled treprostinil in patients with group 1 pulmonary arterial hypertension

Background

Treprostinil is a prostacyclin analogue that directly vasodilates pulmonary and systemic arterial vascular beds. The United States Food and Drug Administration approved inhaled treprostinil in July 2009 for the treatment of group 1 pulmonary arterial hypertension. Inhaled treprostinil avoids issues with continuous infusion prostanoids. This study describes a single institutional experience with inhaled treprostinil.

Methods

This was a retrospective review of group 1 pulmonary arterial hypertension patients receiving inhaled treprostinil from July 2009 through September 2015. Patient demographics, vital signs, prognostic indicators, pulmonary arterial hypertension assessments, treprostinil dosing, pulmonary arterial hypertension medications, and physician assessment were collected. Prognostic indicators and the physician assessment were used to assess treatment response. A modified Registry to Evaluate Early and Long-term Pulmonary Arterial Hypertension Disease Management (REVEAL) risk score was calculated prior to and after initiation of inhaled treprostinil.

Results

The mean time on inhaled treprostinil for the 16 patients was 21 ± 17 months. A total of 31% discontinued treatment. The New York Heart Association Functional Class, right ventricular size, and right ventricular function improved after inhaled treprostinil. Directional improvement in B-type natriuretic peptide, 6-minute walk distance, right arterial pressure and mean pulmonary artery pressure were also observed. The mean modified REVEAL risk score (RRS) was 7 ± 3 at baseline. The RRS decreased in 7 of the 11 patients that improved and remained stable in 2 patients.

Conclusion

The majority of patients in this consecutive series receiving inhaled treprostinil tolerated treatment. Most patients remained on therapy for over 12 months. Clinical assessments of disease severity all changed directionally toward improvement and the overall risk assessment was improved or stable in 56% by the RRS.

A Comprehensive Review of Treprostinil Pharmacokinetics via Four Routes of Administration

Treprostinil is available in three different formulations and four different routes of administration: Remodulin^® (treprostinil sodium, intravenous and subcutaneous administration), Tyvaso^® (treprostinil sodium, inhaled administration), and Orenitram^® (treprostinil diolamine, oral administration) for the treatment of pulmonary arterial hypertension (PAH). Pharmacokinetic studies have been performed in healthy volunteers and patients with PAH. The intent of this review is to outline pharmacokinetic considerations of the three treprostinil formulations and provide clinicians with a resource that may support clinical decisions in treating patients with PAH.

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.

Steps forward in the treatment of pulmonary arterial hypertension: latest developments and clinical opportunities

Pulmonary arterial hypertension (PAH) is a chronic disease that results in narrowing of the small pre-capillary pulmonary arteries leading to elevation of pulmonary artery pressure and pulmonary vascular resistance, subsequent right ventricular failure, and if unchecked, death. Advances in the treatment of PAH over the last two decades have markedly improved survival. These improvements reflect a combination of changes in treatments, improved patient care strategies, and varying disease phenotypes in the PAH population. Currently approved therapies for PAH are directed at the recognized abnormalities within the pulmonary vasculature and include endothelin receptor antagonists, phosphodiesterase-5 inhibitors, soluble guanylate cyclase stimulators, and prostacyclin pathway agents. Most of these drugs have been approved on the basis of short-term trials that mainly demonstrated improvements in exercise capacity. More recently, long-term, event-driven trials of novel drugs have been performed, demonstrating new efficacy parameters. There have also been exciting advances in the understanding of right heart failure pathophysiology in PAH that have the potential to inspire the development of right ventricular targeted therapy and continued discoveries in the heterogeneity of disease and response to treatment has great potential for developing more 'personalized' therapeutic options. In this article, we review the current available data regarding the management of PAH, with an emphasis on the pharmacologic therapies and discussion of novel therapeutic directions for the treatment of this fatal disease.

An observational study of inhaled-treprostinil respiratory-related safety in patients with pulmonary arterial hypertension

Inhaled treprostinil (Tyvaso) has been shown to be a safe and effective addition to pulmonary arterial hypertension (PAH) oral therapies; however, the respiratory-related safety profile of inhaled treprostinil required further elucidation in the setting of routine clinical care. The objectives of this study were to characterize respiratory-related adverse events (AEs) associated with current or recent treatment with inhaled treprostinil and to compare the incidence of respiratory-related AEs in PAH patients treated with inhaled treprostinil with that in patients treated with other Food and Drug Administration (FDA)-approved PAH therapies. This was a long-term, prospective, observational study. All respiratory-related AEs were recorded during the study. The number of PAH patients enrolled was 1,333, 666 treated with inhaled treprostinil and 667 controls (treated with an FDA-approved PAH therapy other than inhaled treprostinil), for a total of 958 and 1,094 patient-years of exposure, respectively. In the inhaled-treprostinil group, 1,281 respiratory-related AEs were reported in 403 patients (61%), and in the control group, 1,295 respiratory-related AEs were reported in 388 patients (58%). Cough, throat irritation, nasal discomfort, and hemoptysis were the most common respiratory-related AEs (occurring in ≥2% of patients in either treatment group) that demonstrated a higher number of events per patient-year of exposure in the inhaled-treprostinil group than in the control group (risk ratio [95% confidence interval]: 1.487 [1.172-1.887], 3.777 [2.050-6.956], 2.039 [1.072-3.879], and 1.957 [1.024-3.741], respectively). Overall, inhaled treprostinil was well tolerated by PAH patients in routine clinical care, with respiratory-related AEs consistent with the known safety profile (trial registration: clinicaltrials.gov identifier: NCT01266265).

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.

Safety and Tolerability of High-dose Inhaled Treprostinil in Pulmonary Hypertension

Pulmonary arterial hypertension (PAH) has emerging therapeutic options including prostacyclin analogs. Inhaled therapy offers advantages compared with alternative routes of administration. We aimed to determine the safety and tolerability of inhaled treprostinil (iTRE) titrated to target maintenance dose higher than the labeled dose for PAH. Our study included 80 consecutive patients (69% female, 70% White) followed at the Duke University Medical Center prescribed iTRE at dose >9 breaths (54 μg). Etiology of pulmonary hypertension was most frequently PAH (51%) or secondary to lung disease (35%). Median follow-up was 20.3 months (interquartile range 14.2-33.2). Most patients (91%) had titrated iTRE dose to 12 breaths (72 μg) four times daily. Common side effects reported with drug initiation were cough (41%), headache (28%), and throat irritation (8%); most of the side effects improved at follow-up. Overall, 25% patients discontinued iTRE: 9 transitioned to parenteral therapy, 4 had untolerable side effects, 3 died, and 4 had other reasons. Overall, iTRE taken at a higher dose than approved for use in PAH was safe and well-tolerated in our cohort of pulmonary hypertension patients.

Pediatric Cardiac Intensive Care Society 2014 Consensus Statement: Pharmacotherapies in Cardiac Critical Care Pulmonary Hypertension

OBJECTIVE

To review the pharmacologic treatment options for pulmonary arterial hypertension in the cardiac intensive care setting and summarize the most-recent literature supporting these therapies.

DATA SOURCES AND STUDY SELECTION

Literature search for prospective studies, retrospective analyses, and case reports evaluating the safety and efficacy of pulmonary arterial hypertension therapies.

DATA EXTRACTION

Mechanisms of action and pharmacokinetics, treatment recommendations, safety considerations, and outcomes for specific medical therapies.

DATA SYNTHESIS

Specific targeted therapies developed for the treatment of adult patients with pulmonary arterial hypertension have been applied for the benefit of children with pulmonary arterial hypertension. With the exception of inhaled nitric oxide, there are no pulmonary arterial hypertension medications approved for children in the United States by the Food and Drug Administration. Unfortunately, data on treatment strategies in children with pulmonary arterial hypertension are limited by the small number of randomized controlled clinical trials evaluating the safety and efficacy of specific treatments. The treatment options for pulmonary arterial hypertension in children focus on endothelial-based pathways. Calcium channel blockers are recommended for use in a very small, select group of children who are responsive to vasoreactivity testing at cardiac catheterization. Phosphodiesterase type 5 inhibitor therapy is the most-commonly recommended oral treatment option in children with pulmonary arterial hypertension. Prostacyclins provide adjunctive therapy for the treatment of pulmonary arterial hypertension as infusions (IV and subcutaneous) and inhalation agents. Inhaled nitric oxide is the first-line vasodilator therapy in persistent pulmonary hypertension of the newborn and is commonly used in the treatment of pulmonary arterial hypertension in the ICU. Endothelin receptor antagonists have been shown to improve exercise tolerance and survival in adult patients with pulmonary arterial hypertension. Soluble guanylate cyclase stimulators are the first drug class to be Food and Drug Administration approved for the treatment of chronic thromboembolic pulmonary hypertension.

CONCLUSIONS

Literature and data supporting the safe and effective use of pulmonary arterial hypertension therapies in children in the cardiac intensive care are limited. Extrapolation of adult data has afforded safe medical treatment of pulmonary hypertension in children. Large multicenter trials are needed in the search for safe and effective therapy of pulmonary hypertension in children.

Survival with sildenafil and inhaled iloprost in a cohort with pulmonary hypertension: an observational study

Background

Combination therapy is frequently used to treat patients with pulmonary hypertension but few studies have compared treatment regimens. This study examined the long-term effect of different combination regimens of inhaled iloprost and oral sildenafil on survival and disease progression.

Methods

This was a retrospective study of patients in the Giessen Pulmonary Hypertension Registry who received iloprost monotherapy followed by addition of sildenafil (iloprost/sildenafil), sildenafil monotherapy followed by addition of iloprost (sildenafil/iloprost), or upfront combination therapy (iloprost + sildenafil). The primary outcome was transplant-free survival (Kaplan–Meier analysis). When available, haemodynamic parameters and 6-minute-walk distance were evaluated.

Results

Overall, 148 patients were included. Baseline characteristics were similar across treatment groups; however, the iloprost + sildenafil cohort had higher mean pulmonary vascular resistance and pulmonary arterial pressure than the others. Transplant-free survival differed significantly between groups (P = 0.007, log-rank test). Cumulative transplant-free survival was highest for patients who received iloprost/sildenafil (1 year survival: iloprost/sildenafil, 95.1 %; sildenafil/iloprost, 91.8 %; iloprost + sildenafil, 62.9 %); this group also remained on monotherapy significantly longer than the sildenafil/iloprost group (median 17.0 months vs 7.0 months, respectively; P = 0.004). Compared with pre-treatment values, mean 6-minute-walk distance increased significantly for all groups 3 months after beginning combination therapy.

Conclusions

In this observational study of patients with pulmonary hypertension receiving combination therapy with iloprost and sildenafil, cumulative transplant-free survival was highest in those who received iloprost monotherapy initially. However, owing to the size and retrospective design of this study, further research is needed before making firm treatment recommendations.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-015-0164-2) contains supplementary material, which is available to authorized users.

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.

Use of outcome measures in pulmonary hypertension clinical trials

OBJECTIVES

To evaluate the use of surrogate measures in pulmonary hypertension (PH) clinical trials and how it relates to clinical practice.

BACKGROUND

Studies of pulmonary arterial hypertension (PAH) employ a variety of surrogate measures in addition to clinical events because of a small patient population, participant burden, and costs. The use of these measures in PH drug trials is poorly defined.

METHODS

We searched PubMed/MEDLINE/Embase for randomized or prospective cohort PAH clinical treatment trials from 1985 to 2013. Extracted data included intervention, trial duration, study design, patient characteristics, and primary and secondary outcome measures. To compare with clinical practice, we assessed the use of surrogate measures in a clinical sample of patients on PH medications at Duke University Medical Center between 2003 and 2014.

RESULTS

Between 1985 and 2013, 126 PAH trials were identified and analyzed. Surrogate measures served as primary endpoints in 119 trials (94.0%). Inclusion of invasive hemodynamics decreased over time (78.6%, 75.0%, 52.2%; P for trend = .02), while functional testing (7.1%, 60.0%, 81.5%; P for trend < .0001) and functional status or quality of life (0%, 47.6%, 62.8%; P for trend < .0001) increased in PAH trials over the same time periods. Echocardiography data were reported as a primary or secondary outcome in 32 trials (25.4%) with increased use from 1985-1994 to 1995-2004 (7.1% vs 35.0%, P = .04), but the trend did not continue to 2005-2013 (25.0%). In comparison, among 450 patients on PAH therapies at our institution between 2003 and 2013, clinical assessments regularly incorporated serial echocardiography and 6-minute walk distance tests (92% and 95% of patients, respectively) and repeat measurement of invasive hemodynamics (46% of patients).

CONCLUSIONS

The majority of PAH trials have utilized surrogate measures as primary endpoints. The use of these surrogate endpoints has evolved significantly over time with increasing use of patient-centered endpoints and decreasing or stable use of imaging and invasive measures. In contrast, imaging and invasive measures are commonly used in contemporary clinical practice. Further research is needed to validate and standardize currently used measures.

Pulmonary arterial hypertension: a review in pharmacotherapy

Pulmonary arterial hypertension (PAH) is a progressive disease that remains incurable. The past 2 decades have witnessed many advances in PAH-directed therapies. More recently, 3 new oral agents have become available in the United States within the past 2 years. Treprostinil is now available in extended-release oral tablets. Macitentan is the third endothelin receptor antagonist approved for use, demonstrating benefits on morbidity and mortality among patients with PAH in an event-driven study. Riociguat is the first soluble guanylate cyclase stimulator that has been approved for use in the United States. This article reviews the clinical efficacy and safety of these 3 agents and the roles they play in the management of PAH. Additionally, we review the limitations of using surrogate markers such as change in 6-minute walk distance to assess disease progression.

Prostanoid therapies in the management of pulmonary arterial hypertension

Prostacyclin is an endogenous eicosanoid produced by endothelial cells; through actions on vascular smooth-muscle cells, it promotes vasodilation. Pulmonary arterial hypertension (PAH) is characterized by elevated mean pulmonary artery pressure due to a high pulmonary vascular resistance state. A relative decrease in prostacyclin presence has been associated with PAH; this pathway has thus become a therapeutic target. Epoprostenol, the synthetic equivalent of prostacyclin, was first utilized as short-term or bridging therapy in the 1980s. Further refinement of its long-term use via continuous intravenous infusion followed. A randomized controlled trial by Barst et al in 1996 demonstrated functional, hemodynamic, and mortality benefits of epoprostenol use. This work was a groundbreaking achievement in the management of PAH and initiated a wave of research that markedly altered the dismal prognosis previously associated with PAH. Analogs of prostacyclin, including iloprost and treprostinil, exhibit increased stability and allow for an extended array of parenteral and non-parenteral (inhaled and oral) therapeutic options. This review further examines the pharmacology and clinical use of epoprostenol and its analogs in PAH.

Riociguat for the treatment of pulmonary arterial hypertension: a long-term extension study (PATENT-2)

Riociguat is a soluble, guanylate cyclase stimulator, approved for pulmonary arterial hypertension. In the 12-week PATENT-1 study, riociguat was well tolerated and improved several clinically relevant end-points in patients with pulmonary arterial hypertension who were treatment naïve or had been pretreated with endothelin-receptor antagonists or prostanoids. The PATENT-2 open-label extension evaluated the long-term safety and efficacy of riociguat. Eligible patients from the PATENT-1 study received riociguat individually adjusted up to a maximum dose of 2.5 mg three times daily. The primary objective was to assess the safety and tolerability of riociguat; exploratory efficacy assessments included 6-min walking distance and World Health Organization (WHO) functional class. Overall, 396 patients entered the PATENT-2 study and 324 (82%) were ongoing at this interim analysis (March 2013). The safety profile of riociguat in PATENT-2 was similar to that observed in PATENT-1, with cases of haemoptysis and pulmonary haemorrhage also being observed in PATENT-2. Improvements in the patients', 6-min walking distance and WHO functional class observed in PATENT-1 persisted for up to 1 year in PATENT-2. In the observed population at the 1-year time point, mean±sd 6-min walking distance had changed by 51±74 m and WHO functional class had improved in 33%, stabilised in 61% and worsened in 6% of the patients versus the PATENT-1 baseline. Long-term riociguat was well tolerated in patients with pulmonary arterial hypertension, and led to sustained improvements in exercise capacity and functional capacity for up to 1 year.

Experimentation with aerosol bonsetan, pirfenidone, treprostinil and sidenafil

INTRODUCTION

Pulmonary hypertension (PH) has been identified either as a symptom or a primary entity. Several drugs are already on the market and other are being investigated. Idiopathic pulmonary fibrosis (IPF) is also a disease were several drugs are being investigated.

MATERIALS AND METHODS

Three jet nebulizers and three ultrasound nebulizers were used for our experiments with seven different residual cups and four different loadings. Bonsetan, treprostinil, sidenafil and pirfenidone were modified in order to be produced as aerosol in an effort to identify parameters which influence the droplet size production size.

RESULTS

The four-way ANOVA on droplet size using the jet nebulizers revealed two statistically significant factors, drug (F=6.326, P=0.0007) and residual cup (F=4.419, P=0.0007), and their interaction term (F=5.829, P<0.0001). Drugs bonsetan and pirfenidone produce equally the lowest mean droplet size (2.63 and 2.80 respectively) as compared to other two drug mean sizes. The ANOVA results, concerning the ultrasound nebulizers, revealed only the nebulizers as producing significant effect on droplet size (F=4.753, P=0.037).

DISCUSSION

Our study indicates the importance of the initial drug design formulation. Moreover, further investigation of the residual cup design is an additional parameter that can assist in the optimal droplet size production, indifferently of the drug formulation.

Pharmacologic therapy for pulmonary arterial hypertension in adults: CHEST guideline and expert panel report

OBJECTIVE

Choices of pharmacologic therapies for pulmonary arterial hypertension (PAH) are ideally guided by high-level evidence. The objective of this guideline is to provide clinicians advice regarding pharmacologic therapy for adult patients with PAH as informed by available evidence.

METHODS

This guideline was based on systematic reviews of English language evidence published between 1990 and November 2013, identified using the MEDLINE and Cochrane Library databases. The strength of available evidence was graded using the Grades of Recommendations, Assessment, Development, and Evaluation methodology. Guideline recommendations, or consensus statements when available evidence was insufficient to support recommendations, were developed using a modified Delphi technique to achieve consensus.

RESULTS

Available evidence is limited in its ability to support high-level recommendations. Therefore, we drafted consensus statements to address many clinical questions regarding pharmacotherapy for patients with PAH. A total of 79 recommendations or consensus statements were adopted and graded.

CONCLUSIONS

Clinical decisions regarding pharmacotherapy for PAH should be guided by high-level recommendations when sufficient evidence is available. Absent higher level evidence, consensus statements based upon available information must be used. Further studies are needed to address the gaps in available knowledge regarding optimal pharmacotherapy for PAH.

Current and advancing treatments for pulmonary arterial hypertension in childhood

Pulmonary arterial hypertension (PAH) is a severe and progressive intrinsic disease of the precapillary lung vasculature. Since the introduction of PAH-targeted drugs, survival of PAH patients seems to have improved. Randomized controlled trials have led to evidence-based guidelines to direct treatment in adults. However, since disease characteristics differ between adults and children, it is hazardous to simply extrapolate these guidelines to children. Moreover, pediatric data on treatment strategies and how to assess treatment response remain virtually absent. Optimal treatment strategies are highly needed to guide therapy and improve survival in children with PAH. This review provides an overview of currently available treatments for PAH and the limited efficacy and safety data in children (with the exclusion of perinatal pulmonary vascular diseases, as persistent pulmonary hypertension of the newborn). We also discuss potential treatment goals and how the available data can be translated into treatment strategies in pediatric PAH.

Clinical utility of treprostinil in the treatment of pulmonary arterial hypertension: an evidence-based review

Pulmonary arterial hypertension (PAH) remains a progressive disease without a cure, despite the development of several treatment options over the past several decades. Its management strategy consists of the endothelin receptor antagonists (ambrisentan, bosentan, macitentan), phosphodiesterase-5 inhibitors (sildenafil, tadalafil, vardenafil), and prostacyclin analogs (epoprostenol, treprostinil, iloprost). Treprostinil, a stable prostacyclin analog, displays vasodilatory effects in the pulmonary vasculature, as well as antiplatelet aggregation properties. Clinical practice guidelines recommend oral endothelin receptor antagonist or phosphodiesterase inhibitor therapy in mild to moderate PAH. Epoprostenol is specifically suggested as first-line therapy in moderate to severe PAH patients (ie, World Health Organization/New York Heart Association functional class III-IV). However, treprostinil may be an alternative option in these severe PAH patients. The longer half-life and stability at room temperature with treprostinil may be associated with lower risk of pulmonary hemodynamic worsening as a result of abrupt infusion discontinuation and less frequent drug preparation. These characteristics make treprostinil an attractive alternative to continuous infusion of epoprostenol, due to convenience and patient safety. The purpose of this review is to evaluate the safety and efficacy of continuous infusion of treprostinil as well as the inhaled and oral routes of administration in PAH.

Transition from intravenous or subcutaneous prostacyclin therapy to inhaled treprostinil in patients with pulmonary arterial hypertension: a retrospective case series

WHAT IS KNOWN AND OBJECTIVE

Inhaled treprostinil represents an attractive alternative to the other available prostacyclin formulations by obviating the use of continuous infusions and its associated risks. Published evidence describing the process of transition from infusion prostacyclin therapy to inhaled treprostinil is limited. The purpose of this report is to describe an inpatient protocol for transitioning patients with pulmonary arterial hypertension (PAH) from intravenous (IV) or subcutaneous (SQ) prostacyclin therapy to inhaled treprostinil.

METHODS

A retrospective case cohort study was performed evaluating medical records of three patients undergoing transition from IV/SQ continuous infusion prostacyclin therapy to inhaled treprostinil. The transition protocol and clinical data were collected prospectively.

RESULTS AND DISCUSSION

Haemodynamics, six-min walk distance (6MWD), World Health Organization (WHO) functional class, modified Borg Dyspnea Score and brain natriuretic peptide prior to and after transition remained similar. All patients were receiving concomitant oral PAH medications prior to and after conversion. Adverse effects during the change were mild. No patients discontinued inhaled treprostinil following transition. At long-term follow-up, functional class remained stable at WHO functional class II or better. Patient 1 and Patient 3 demonstrated stable to modest improvement in 6MWD, whereas Patient 2 had a slight decrease in 6MWD. The transition to inhaled treprostinil from IV/SQ infusion prostacyclin therapy appears to be safe in carefully selected patients.

WHAT IS NEW AND CONCLUSION

Our report describes a standard method used to transition patients from IV/SQ infusion prostacyclin to inhaled treprostinil.

Long-term sildenafil added to intravenous epoprostenol in patients with pulmonary arterial hypertension

BACKGROUND

In pulmonary arterial hypertension (PAH), adding oral sildenafil to intravenous epoprostenol improved 6-minute walk distance (6MWD) and hemodynamics and delayed time to clinical worsening in a 16-week randomized, placebo-controlled trial (Pulmonary Arterial Hypertension Combination Study of Epoprostenol and Sildenafil [PACES-1]).

METHODS

Patients completing PACES-1 could receive sildenafil (titrated to 80 mg, three times daily, as tolerated) in an open-label extension study (PACES-2) for ≥ 3 years; additional therapy was added according to investigator judgment. Survival and changes from PACES-1 baseline in World Health Organization Functional Class and 6MWD were captured.

RESULTS

In an open-label setting, 6MWD, an effort-dependent outcome measure, was known to have improved or to have been maintained in 59%, 44%, and 33% of patients at 1, 2, and 3 years, respectively; functional class was known to have improved or to have been maintained in 73%, 59%, and 46%. At 3 years, 66% of patients were known to be alive, 24% were known to have died, and 10% were lost to follow-up. Patients with PACES-1 baseline 6MWD < 325 meters without 6MWD improvement during the first 20 weeks of sildenafil treatment subsequently had poorer survival.

CONCLUSIONS

Although reliable assessments of safety and efficacy require a long-term randomized trial, the addition of sildenafil to background intravenous epoprostenol therapy appeared generally to be well tolerated in PAH patients.