Ralinepag Phase II Open-Label Extension Study in Patients with Pulmonary Arterial Hypertension.

INTRODUCTION: Ralinepag is a potent, titratable, orally administered prostacyclin (IP) receptor agonist to treat pulmonary arterial hypertension. A phase II randomized, double-blind, parallel-group, placebo-controlled, 22-week study of immediate-release (IR) ralinepag safety and efficacy met its primary endpoint, significantly reducing pulmonary vascular resistance (PVR) compared with placebo. This phase II open-label extension (OLE) study assessed long-term safety and tolerability of ralinepag. METHODS: Participants were eligible for the OLE if they completed the parent study or experienced a clinical worsening event while receiving placebo. Those previously receiving IR ralinepag remained on their current dose, and participants formerly administered placebo were titrated to the highest tolerated dose. Participants were transitioned to an extended-release ralinepag formulation toward the end of the OLE. The primary objective evaluated long-term safety and tolerability; secondary endpoints included changes in 6-min walk distance (6MWD), World Health Organization/New York Heart Association functional class, clinical worsening, and hemodynamic measures. RESULTS: In total, 45/61 participants enrolled in the OLE study, 30 from the IR ralinepag group and 15 from the placebo group. The most common adverse events (AEs) were known prostacyclin-related effects (e.g., headache, 64.4%; diarrhea, 37.8%; jaw pain, 33.3%). There was a notable decline in AEs after reaching and maintaining a stable dose. At month 24 after entering the OLE, 6MWD significantly increased by a mean of 36.3 m (P = 0.004) from OLE baseline, and most participants remained stable in their functional class (84.8%). Post-baseline PVR in 1 or 2 years decreased by a median of 52.2 dyn.s/cm5 and mean pulmonary arterial pressure decreased by a median of 2.0 mmHg (P = 0.05). CONCLUSION: Ralinepag produced sustained, durable improvements in 6MWD along with durable reductions in PVR and a manageable AE profile. Most participants continuing treatment with ralinepag maintained functional measures throughout the OLE and those switching from placebo to ralinepag often experienced functional improvements.

Pulmonary arterial hypertension is a rare disease caused by elevated pressure in the blood vessels connecting the heart to the lungs. A previous phase 2 study found that ralinepag significanlty reduced pulmonary vascular resistance (the force or resistance that blood encounters as it flows through the blood vessels in the lungs) compared with placebo. This clinical study of 45 patients investigated whether ralinepag was safe and effective for long-term use to treat people with pulmonary arterial hypertension. All participants received ralinepag twice daily until a new once daily pill was available later in the study. The primary endpoints were long-term safety and tolerability, and secondary endpoints included exercise capacity, impact on daily life (functional class), clinical worsening, and hemodynamic measures (metrics to measure how well the heart is working). The study found that ralinepag had a manageable side effect profile, with a decrease in side effects for patients who continued taking ralinepag over time. Moreover, the study showed that ralinepag improved the ability to exercise, maintained functional measures, and helped to reduce pressure in the blood vessels connecting the heart to the lungs over a 24-month period for participants with pulmonary arterial hypertension.

Angiotensin converting enzyme inhibitor potentiates the hypoglycaemic effect of NG-nitro-L-arginine methyl ester (L-NAME) in rats.

The inhibition of renin angiotensin system pathway has been largely documented to be effective in the control of cardiovascular events. The present study investigated the effect of angiotensin converting enzyme (ACE) inhibitor on fasting blood glucose level in hypertension induced by the inhibition of nitric oxide synthase (NOS) in male Wistar rats. Hypertension was induced by the inhibition of NOS using a non-selective NOS inhibitor, NG-nitro-L-arginine methyl ester (L-NAME). The blockade of NOS resulted in an increase in blood pressure, ACE, angiotensin II and endothelin-1 levels, and a decrease in fasting blood glucose and nitric oxide (NO) levels. The hypertensive rats treated with ACE inhibitor (ramipril) recorded a decrease in blood pressure, ACE, angiotensin II, endothelin-1, NO and fasting blood glucose levels, and an increase in prostacyclin level. In conclusion, ACE inhibitor potentiated the hypoglycaemic effect of NOS inhibitor and this effect is independent of NO and pancreatic insulin release.

Pulmonary arterial hypertension in the emergency department: A focus on medication management.

Pulmonary arterial hypertension (PAH) is a chronic progressive incurable condition associated with a high degree of morbidity and mortality. With over five drug classes FDA approved in the last decade, the significant advancements in the pharmacologic management of PAH has improved long-term outcomes. Drug therapies have been developed to directly target the underlying pathogenesis of PAH including phosphodiesterase type-5 inhibitors (PDE-5i), endothelin-receptor antagonists (ERAs), guanylyl-cyclase inhibitors, prostacyclin analogues, and prostacyclin receptor agonists. Although these agents offer remarkable benefits, there are significant challenges with their use such as complexities in medication dosing, administration, and adverse effects. Given these consequences, PAH medications are classified as high-risk, and the transitions of care process to and from the hospital setting are a vulnerable area for medication errors in this population. Thus, it is crucial for the emergency department provider to appropriately identify, manage, and triage these patients through close collaboration with a multidisciplinary team to ensure safe and effective medication management for PAH patients in the acute care setting.

Thrombocytopenia During Prostacyclin Analogue Therapies of Pulmonary Arterial Hypertension-Possible Pathomechanisms and Implications.

Pulmonary arterial hypertension is a quite rare, but problematic disease in everyday cardiologists' practice. Prostanoids are the most important group of drugs used in this disease. One of the biggest problems encountered during treatment with analogs of prostacyclin is thrombocytopenia. Based on hematological guidelines we suggest common therapeutic schemes depending on the number of platelets or the severity of bleeding conducting the therapy.

Experience in Transitioning From Parenteral Prostacyclins to Selexipag in Pulmonary Arterial Hypertension.

Parenteral prostacyclin therapies remain first-line therapy for patients with pulmonary arterial hypertension (PAH) with class IV symptoms. In selected patients who have been clinically stabilized, switching to selexipag, a chemically distinct prostacyclin receptor agonist, may alleviate risks associated with long-term parenteral therapy. We report our experience with transition of patients from parenteral prostacyclin therapy to selexipag. From January 2016 to July 2017, patients with PAH at the Duke University Pulmonary Vascular Disease Center with functional class II symptoms on stable parenteral prostacyclin therapy were offered the opportunity to transition to selexipag. A standardized protocol was developed to guide titration of therapies. Patients underwent pre- and post-transition assessments of hemodynamics, echocardiography, laboratory biomarkers, and functional status. We studied 14 patients with PAH (11 women; median age 53 years) in total. Overall, 13 patients tolerated the switch to selexipag and remained on the drug at study completion, and 1 patient passed away due to progressive liver failure. Surrogate markers including NT-proBNP, 6MWD, RV function, and TAPSE, and right heart catheterization hemodynamics were similar before and after transition. The transition from parenteral prostanoid therapy to oral selexipag was overall well-tolerated in patients with stable PAH and functional class II symptoms. Finally, doses of selexipag up to 3200 µg twice daily were well-tolerated in patients who had been treated with prior parenteral prostacyclins.

Low Rate of Adverse Events Associated With Inpatient Parenteral Prostacyclins.

Parenteral prostacyclin is the most-effective therapy for patients with pulmonary arterial hypertension. Administration is complex, and administration errors are potentially life threatening. Hospital policies to minimize the risk to patients are necessary, but their effectiveness has not been well studied. We quantified the adverse event incident rate per at-risk patient day in a tertiary care hospital with an established parenteral prostacyclin policy. Patients on parenteral prostacyclin including new initiations from January 2003 to January 2013 were identified, encompassing 386 discrete admissions. Reports of adverse events were obtained from the inpatient risk feedback-reporting process and detailed chart review. Policy-divergent events were analyzed both categorically and by the degree of severity. Overall, 153 total policy-divergent events were identified. Data analysis indicated an incident rate of 45.9 per 1,000 patient days. In total, 21 of 153 potential errors reached the patient, translating to an incident rate of 6.3 per 1,000 patient days. Incident rate for "serious symptomatic" or "catastrophic" policy-divergent events was 3.3 per 1,000 patient days. Even with specific prostacyclin training and administration policy, there remains a small risk of adverse events in hospitalized pulmonary hypertension patients receiving parenteral prostacyclin.

Comparative Safety and Tolerability of Prostacyclins in Pulmonary Hypertension.

Prostacyclin (PGI2) is a prostaglandin derived from arachidonic acid in the endothelium and smooth muscle which causes vasodilation, inhibits platelet aggregation, and has anti-inflammatory, anti-thrombotic and anti-proliferative effects. In pulmonary arterial hypertension (PAH), PGI2 levels and PGI2 synthase expression are reduced, contributing to the vasoconstriction and vascular smooth muscle cell proliferation seen in the disease. Based on these findings, PGI2 analogues were developed to target this pathway. Epoprostenol was the first targeted therapy available for treating PAH. Due to the short half-life of this drug, it requires administration via a continuous intravenous infusion, and therefore it carries the risks of central line infections and thrombosis. However, it remains the treatment of choice in patients with severe PAH as it has a proven survival benefit as well as improved functional class and exercise capacity. Subsequently, several other PGI2 analogues have been developed with differing modes of administration and varying degrees of efficacy. Beraprost is an oral PGI2 analogue for which a sustained efficacy has not been demonstrated. Iloprost is a nebulised PGI2 analogue that requires administration six to nine times a day and leads to improved functional class, exercise capacity and haemodynamics. There are inhaled, oral, subcutaneous and intravenous forms of treprostinil. Subcutaneous treprostinil avoids the risks of a continuous intravenous administration; however, this drug can cause intractable pain at the injection site. Selexipag is the new oral non-prostanoid IP prostacyclin receptor agonist that has shown improved haemodynamics and good tolerance in a phase II study. Initial results of the phase III trial are promising. Comparison of the different PGI2 agents is limited by a lack of head-to-head clinical trials. However, the development of PGI2 analogues has improved survival in patients with PAH and remains the main treatment option in advanced disease. While PGI2 analogues have good efficacy in PAH, they are not interchangeable, and their delivery systems have many limitations; in particular, they are associated with significant deleterious consequences. In the future, it is hoped that the elusive goal of developing an effective oral PGI2 analogue will be achieved. This would increase the number of people who could benefit from the treatment while reducing the associated adverse events, and as a result improve the survival and quality of life for these patients.

Recent advances in targeting the prostacyclin pathway in pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is a severe disease characterised by increased pulmonary vascular resistance, which leads to restricted pulmonary arterial blood flow and elevated pulmonary arterial pressure. In patients with PAH, pulmonary concentrations of prostacyclin, a prostanoid that targets several receptors including the IP prostacyclin receptor, are reduced. To redress this balance, epoprostenol, a synthetic prostacyclin, or analogues of prostacyclin have been given therapeutically. These therapies improve exercise capacity, functional class and haemodynamic parameters. In addition, epoprostenol improves survival among patients with PAH. Despite their therapeutic benefits, treatments that target the prostacyclin pathway are underused. One key factor is their requirement for parenteral administration: continuous intravenous administration can lead to embolism and thrombosis; subcutaneous administration is associated with infusion-site pain; and inhalation is time consuming, requiring multiple daily administrations. Nevertheless, targeting the prostacyclin pathway is an important strategy for the management of PAH. The development of oral therapies for this pathway, as well as more user-friendly delivery devices, may alleviate some of the inconveniences. Continued improvements in therapeutic options will enable more patients with PAH to receive medication targeting the prostacyclin pathway.

Pulmonary arterial hypertension: new insights into the optimal role of current and emerging prostacyclin therapies.

Pulmonary arterial hypertension (PAH), which is a subset of pulmonary hypertension, is a group of diseases distinguished by vascular remodeling of the small pulmonary arteries with associated elevated pulmonary arterial pressure and right ventricular failure. This progressive and sometimes fatal disease occurs as an idiopathic disease or as a component of other disease states. Estimates of the incidence of PAH have varied from 5 to 52 cases/1 million population. Symptoms begin with shortness of breath with exertion and progress to dyspnea with normal activities and, finally, dyspnea at rest. Untreated patients with PAH have a 1-, 3-, and 5-year survival rate of 68%, 48%, and 34%, respectively. Treated, the survival rates improve to 91% to 97% after 1 year and 84% to 91% after 2 years. The current definition of PAH consists of 3 specific hemodynamic assessments confirmed by right heart catheterization findings. One of several important pathophysiologic mechanisms involved in PAH is pulmonary vascular remodeling, which is caused by endothelial and smooth muscle cell hyperproliferation. This is coincident with overexpression of the vasoconstrictor endothelin-1 and a reduction in the vasodilators nitric oxide and prostacyclin, which further impedes proper vasomotor tone, among other effects. Prostacyclin therapies augment the decreased prostacyclin levels in patients with PAH. The currently approved prostacyclins for the treatment of PAH include epoprostenol, iloprost, and treprostinil. Among the 3 medications, the delivery options include intravenous infusion, subcutaneous infusion, and inhaled formulations. Epoprostenol has been shown to have a positive effect on survival in patients with PAH. All prostacyclins have demonstrated improvements in functional class, exercise tolerance, and hemodynamics in patients with PAH. Intravenously and subcutaneously administered formulations of prostacyclins require continuous infusion pump administration, which presents clinical challenges for both the patient and the care provider. Dosing must be individualized and also presents a clinical challenge. Inhaled formulations seem efficacious in moderately symptomatic patients with PAH and might be appropriate when combined with an oral medication. Combination therapies are commonly used in clinical practice, with the decision to do so based on randomized controlled trial data and case study evidence. The present report provides an overview of PAH, the scientific rationale for treatment with prostacyclin therapy, and the benefits and risks of prostacyclin therapy, both as monotherapy and combined with other medications approved for the treatment of PAH.

Iloprost inhalation in mild asthma.

OBJECTIVE: To determine the feasibility of administering iloprost by inhalation in patients with mild atopic asthma. METHODS: Volunteers underwent supervised inhalation of iloprost in the clinic with measurement of spirometry and blood pressure for 2 hours. The volunteers then inhaled iloprost four times daily at a dose of 2.5 or 5 µg for 14 days. Spirometry, asthma questionnaires, peak flow diaries, measurement of methacholine responsiveness, and exhaled nitric oxide concentrations were obtained prior to and after the treatment period. RESULTS: Chronic inhalation of iloprost (2.5-5 µg) did not alter spirometry or methacholine responsiveness. CONCLUSION: Inhaled iloprost in carefully selected volunteers with mild asthma appears to be a suitable intervention to explore the effects of prostacyclin in human asthma.

Prostacyclins in pulmonary arterial hypertension: the need for earlier therapy.

Pulmonary arterial hypertension (PAH) is a rare but serious condition, which if untreated, is associated with a 2-3-year median survival time. A number of treatment options are available for PAH, leading to improvements in exercise capacity, symptoms, and hemodynamics. However, the disease remains incurable and most patients will ultimately progress to right heart failure and death. Three classes of drugs are currently available to improve PAH outcomes, although this review will focus solely on a class of potent vasodilators known as prostacyclins. Currently, four prostacyclin analogs are licensed for the treatment of PAH: epoprostenol, treprostinil, and iloprost in the USA and some European countries, and beraprost in Japan and Korea. Prostacyclins have become the treatment of choice in patients with severe PAH, but there is also evidence to suggest that their earlier use may also benefit patients with mild-to-moderate disease. This review discusses the advantages of prostacyclins in terms of their usefulness in patients whose condition has deteriorated following monotherapy with other agents, and their integral role in combination therapy. The latter appears to offer the potential for pulmonary vasculature remodeling and could be regarded as an emerging paradigm to treat and prevent the progression of PAH.

[Pathophysiological mechanisms and treatment of septic shock-induced vasoplegia]. / Physiopathologie et traitement de la vasoplégie au cours du sepsis.

The hemodynamics of septic shock is characterized by a primary reduction of vascular tone, which defines vasoplegia. Septic vasoplegia is due to reduced endogenous production of vasopressin, as well as to the overproduction of vasodilating molecules (nitric oxide, prostacyclin, peroxynitrite and kynurenine) and the opening of ATP-sensitive potassium channels. Treatment is supportive and includes primarily alpha-adrenergic catecholamines. Vasopressin may also be useful, although its place is still controversial. Further agents can improve the vascular responsiveness to catecholamines, most notably low doses hydrocortisone, and, to a lesser extent, activated protein C. Further, innovative therapies, based on recent understanding of pathophysiological mechanisms, might become useful agents to treat septic vasoplegia in the future.

Anticoagulation for renal replacement therapy: different methods to improve safety.

The different methods for anticoagulation of the extracorporeal circuit for renal replacement therapy (RRT) vary in safety profile, bleeding being the most important side effect. Avoiding severe bleeding is a key aim of RRT prescription. The present paper is a clinical review comparing regional anticoagulation with citrate to heparin for continuous RRT, and different anticoagulant strategies for prolonged intermittent therapies. Regional anticoagulation with citrate or the use of prostacyclins provide high safety because they do not increase the patient's risk of bleeding. The use of citrate may additionally increase biocompatibility. However, both confer other risks when used without understanding and therefore require carefully designed protocols for bedside use with guidelines for early detection and management of complications. If so, the use of citrate may improve patient and kidney survival. Further studies are needed to confirm and explain this benefit.

Increased sympathetic nerve activity in pulmonary artery hypertension.

BACKGROUND: This study tested the hypothesis that sympathetic nerve activity is increased in pulmonary artery hypertension (PAH), a rare disease of poor prognosis and incompletely understood pathophysiology. We subsequently explored whether chemoreflex activation contributes to sympathoexcitation in PAH. METHODS AND RESULTS: We measured muscle sympathetic nerve activity (MSNA) by microneurography, heart rate (HR), and arterial oxygen saturation (Sao(2)) in 17 patients with PAH and 12 control subjects. The patients also underwent cardiac echography, right heart catheterization, and a 6-minute walk test with dyspnea scoring. Circulating catecholamines were determined in 8 of the patients. Chemoreflex deactivation by 100% O(2) was assessed in 14 patients with the use of a randomized, double-blind, placebo-controlled, crossover study design. Compared with the controls, the PAH patients had increased MSNA (67+/-4 versus 40+/-3 bursts per minute; P<0.0001) and HR (82+/-4 versus 68+/-3 bpm; P=0.02). MSNA in the PAH patients was correlated with HR (r=0.64, P=0.006), Sao(2) (r=-0.53, P=0.03), the presence of pericardial effusion (r=0.51, P=0.046), and NYHA class (r=0.52, P=0.033). The PAH patients treated with prostacyclin derivatives had higher MSNA (P=0.009), lower Sao(2) (P=0.01), faster HR (P=0.003), and worse NYHA class (P=0.04). Plasma catecholamines were normal. Peripheral chemoreflex deactivation with hyperoxia increased Sao(2) (91.7+/-1% to 98.4+/-0.2%; P<0.0001) and decreased MSNA (67+/-5 to 60+/-4 bursts per minute; P=0.0015), thereby correcting approximately one fourth of the difference between PAH patients and controls. CONCLUSIONS: We report for the first time direct evidence of increased sympathetic nerve traffic in advanced PAH. Sympathetic hyperactivity in PAH is partially chemoreflex mediated and may be related to disease severity.

Aerosolized prostacyclins.

Two prostacyclins (prostaglandin E(1) and prostaglandin I(2)) are potent vasodilators. Aerosolized prostacyclins reduce pulmonary artery pressure, improve right heart function, and increase arterial oxygenation by improving ventilation/perfusion matching. This report describes aerosolized prostacyclins and compares them to inhaled nitric oxide. I review the types of inhalable prostacyclins and their indications, evidence of efficacy, delivery, and adverse effects.