Results of European post-marketing surveillance of bosentan in pulmonary hypertension

Pulmonary arterial hypertension: Navigating the pathways of progress in diagnosis, treatment, and patient care

Pulmonary arterial hypertension (PAH) is a form of precapillary pulmonary hypertension caused by a complex process of endothelial dysfunction and vascular remodeling. If left untreated, this progressive disease presents with symptoms of incapacitating fatigue causing marked loss of quality of life, eventually culminating in right ventricular failure and death. Patient management is complex and based on accurate diagnosis, risk stratification, and treatment initiation, with close monitoring of response and disease progression. Understanding the underlying pathophysiology has enabled the development of multiple drugs directed at different targets in the pathological chain. Vasodilator therapy has been the mainstay approach for the last few years, significantly improving quality of life, functional status, and survival. Recent advances in therapies targeting dysfunctional pathways beyond endothelial dysfunction may address the fundamental processes underlying the disease, raising the prospect of increasingly effective options for this high-risk group of patients with a historically poor prognosis.

Removing the FDA's Boxed Hepatotoxicity Warning and Liver Function Testing Requirement for Ambrisentan

Importance

Endothelin receptor antagonists are first-line therapy for pulmonary arterial hypertension (PAH). The first 2 agents approved in the class, bosentan and ambrisentan, initially carried boxed warnings for hepatotoxicity and required monthly liver function tests (LFTs) as part of a risk evaluation and mitigation strategy (REMS); however, in 2011, as further safety data emerged on ambrisentan, the boxed hepatotoxicity warning and LFT requirements were removed.

Objective

To analyze changes in the use of and LFT monitoring for ambrisentan and bosentan after changes to the ambrisentan labeling and REMS.

Design, Setting, and Participants

This serial cross-sectional study used data from 3 longitudinal health care insurance claims databases-Medicaid, Optum's deidentified Clinformatics Data Mart, and Merative Marketscan-to perform an interrupted time series analysis of prescription fills and LFTs for patients taking ambrisentan and bosentan. Participants were patients filling prescriptions for ambrisentan and bosentan from July 1, 2007, to December 31, 2018. Data analysis was performed from April 2021 to August 2023.

Exposure

Removal of the boxed warning for hepatotoxicity and the REMS LFT monitoring requirements on ambrisentan in March 2011.

Main Outcomes and Measures

The primary outcomes were use of ambrisentan (ie, individuals with at least 1 dispensing per 1 000 000 individuals enrolled in the 3 datasets) vs bosentan and LFT monitoring (ie, proportion of initiators with at least 1 ordered test) before initiation and before the first refill.

Results

A total of 10 261 patients received a prescription for ambrisentan during the study period (7442 women [72.5%]; mean [SD] age, 52.6 [17.6] years), and 11 159 patients received a prescription for bosentan (7931 women [71.1%]; mean [SD] age, 47.7 [23.7] years). Removal of the ambrisentan boxed hepatotoxicity warning and LFT monitoring requirement was associated with an immediate increase in the use of ambrisentan (1.50 patients per million enrollees; 95% CI, 1.08 to 1.92 patients per million enrollees) but no significant change in the use of bosentan. There were reductions in recorded LFTs before drug initiation (13.1% absolute decrease; 95% CI, -18.2% to -8.0%) and before the first refill (26.4% absolute decrease; 95% CI, -34.4% to -18.5%) of ambrisentan but not bosentan.

Conclusions and Relevance

In this serial cross-sectional study of ambrisentan, labeling changes and removal of the REMS-related LFT requirement were associated with shifts in prescribing and testing behavior for ambrisentan but not bosentan. Further clinician education may be needed to maximize the benefits of REMS programs and labeling warnings designed to ensure the safe administration of high-risk medications.

Long-term efficacies of selective vasodilators in pulmonary arterial hypertension: a comprehensive comparison using a spontaneous reporting database

There is no clinical evidence of differences in drugs associated with long-term survival in patients with pulmonary arterial hypertension (PAH) due to the small population and lack of information on death in Japanese medical database systems. This study evaluated whether patient data from a spontaneous reporting database could be used for comparing the effects of pulmonary vasodilators on long-term survival in PAH patients. PAH patient data reported in the Japanese Adverse Drug Event Report (JADER) database from April 2004 to July 2022 were extracted. Kaplan-Meier curves were used to compare survival times. Adjusted hazard ratios (aHRs) for all-cause mortality were determined using Cox proportional hazards models. Of 1969 PAH patients reported in the JADER database, 1208 were included in the survival analyses. The patient demographics were similar to those of the PAH population reported in the Japan Pulmonary Hypertension Registry. Among drugs targeting the prostacyclin pathway, epoprostenol was most associated with long-term survival (aHR, 0.38; 95% confidence interval (CI), 0.23-0.64). The PAH patients treated with endothelin receptor antagonists had improved survival, especially among the macitentan users (aHR, 0.30; 95% CI, 0.22-0.42). Sildenafil was associated with a poor prognosis in the PAH patients (aHR, 1.56; 95% CI, 1.19-2.04). Although our results must be interpreted with caution due to several limitations inherent to spontaneous reporting databases, our approach using the JADER database for survival analysis may provide useful information in limited situations such as the treatment of rare diseases including PAH.

[The importance of data in Pulmonary Arterial Hypertension: from international registries to Machine Learning]

Real-world registries have been critical to building the scientific knowledge of rare diseases, including Pulmonary Arterial Hypertension (PAH). In the past 4 decades, a considerable number of registries on this condition have allowed to improve the pathology and its subgroupś definition, to advance in the understanding of its pathophysiology, to elaborate prognostic scales and to check the transferability of the results from clinical trials to clinical practice. However, in a moment where a huge amount of data from multiple sources is available, they are not always taken into account by the registries. For that reason, Machine Learning (ML) offer a unique opportunity to manage all these data and, finally, to obtain tools that may help to get an earlier diagnose, to help to deduce the prognosis and, in the end, to advance in Personalized Medicine. Thus, we present a narrative revision with the aims of, in one hand, summing up the aspects in which data extraction is important in rare diseases -focusing on the knowledge gained from PAH real-world registries- and, on the other hand, describing some of the achievements and the potential use of the ML techniques on PAH.

Targeting the endothelium by combining endothelin-1 antagonism and SGLT-2 inhibition: better together?

Endothelin A and B receptors, together with sodium-glucose cotransporter-2 (SGLT-2) channels are important targets in improving endothelial function and intervention with inhibitors has been the subject of multiple mechanistic and clinical outcome trials over recent years. Notable successes include the treatment of pulmonary hypertension with endothelin receptor antagonists, and the treatment of heart failure and chronic kidney disease with SGLT-2 inhibitors. With distinct and complementary mechanisms, in this review, we explore the logic of combination therapy for a number of diseases which have endothelial dysfunction at their heart.

Sparsentan: A First-in-Class Dual Endothelin and Angiotensin II Receptor Antagonist

OBJECTIVE

To provide an overview of the guidelines on the management of immunoglobulin A nephropathy (IgAN) and focal segmental glomerulosclerosis (FSGS), review the evidence for sparsentan, and discuss its place in therapy.

DATA SOURCES

A literature search was conducted using MEDLINE, EMBASE, and clinicaltrials.gov using the search terms "sparsentan" and "RE-021" up to the end of Jun 2023.

STUDY SELECTION AND DATA EXTRACTION

English studies were included if they evaluated the pharmacology, pharmacokinetics, efficacy, and safety of sparsentan in human subjects. Information from the Food and Drug Administration (FDA) and manufacturer's monograph were also extracted.

DATA SYNTHESIS

In comparison with irbesartan, sparsentan reduced urine protein-to-creatinine ratio (UPCR) in both IgAN (-49.8% vs -15.1% at interim 36 weeks) and FSGS (-44.8% vs -18.5% at 8 weeks). Hypotension and edema were the most common adverse events in the sparsentan groups. Hepatotoxicity appears to be comparable between sparsentan and irbesartan in short-term results.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE IN COMPARISON WITH EXISTING DRUGS

Sparsentan provides a new option for patients with IgAN who are otherwise at high risk of progressive kidney disease. Continued FDA approval is dependent on long-term study results on renal function decline and safety.

CONCLUSION

Sparsentan reduces proteinuria in IgAN and FSGS, and has expedited approval by the FDA for IgAN in patients at risk of rapid disease progression, generally at urine protein-to-creatinine ratio (UPCR) ≥1.5 g/g. Interim results from PROTECT and results from DUET showed promise for improving proteinuria in IgAN and FSGS. Long-term renal function benefit and safety data are pending.

Bosentan in the treatment of persistent pulmonary hypertension in newborns: a systematic review and meta-analysis

BACKGROUND

Persistent pulmonary hypertension of the newborn is a life-threatening condition that affects about 1-2 per 1,000 live births worldwide. Bosentan is an oral dual endothelin receptor antagonist that may have a beneficial effect on persistent pulmonary hypertension of the newborn by reducing pulmonary vascular resistance and improving oxygenation. However, its role in persistent pulmonary hypertension of the newborn remains unclear.

OBJECTIVES

To systematically evaluate the efficacy and safety of bosentan as an adjuvant therapy for persistent pulmonary hypertension of the newborn in newborns.

METHODS

We searched six English and two Chinese databases from their inception to 1 January 2023 following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We included randomised controlled trials and retrospective studies that compared bosentan with placebo or other drugs for persistent pulmonary hypertension of the newborn in newborns. We performed a meta-analysis using random-effects models and assessed the risk of bias and heterogeneity in the included studies.

RESULTS

We included 10 studies with a total of 550 participants. Bosentan significantly reduced the treatment failure rate (relative risk = 0.25, P < 0.001), pulmonary artery pressure (mean difference = -11.79, P < 0.001), and length of hospital stay (mean difference = -1.04, P = 0.003), and increased the partial pressure of oxygen (mean difference = 10.02, P < 0.001) and blood oxygen saturation (SpO2) (mean difference = 8.24, P < 0.001) compared with a placebo or other drugs. The occurrence of adverse reactions was not significantly different between bosentan and a placebo or other drugs.

CONCLUSIONS

Bosentan is effective in the treatment of persistent pulmonary hypertension of the newborn but adverse reactions such as abnormal liver function should be observed when using it.

Management of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a rare pulmonary vascular disease characterized by progressive pulmonary arterial remodeling, increased pulmonary vascular resistance, right ventricular dysfunction, and reduced survival. Effective therapies have been developed that target three pathobiologic pathways in PAH: nitric oxide, endothelin-1, and prostacyclin. Approved therapies for PAH include phosphodiesterase type-5 inhibitors, soluble guanylate cyclase stimulators, endothelin receptor antagonists, prostacyclin analogs, and prostacyclin receptor agonists. Management of PAH in the modern era incorporates multidimensional risk assessment to guide the use of these medications. For patients with PAH and without significant comorbidities, current guidelines recommend two oral medications (phosphodiesterase type-5 inhibitor and endothelin receptor antagonist) for low- and intermediate-risk patients, with triple therapy including a parenteral prostacyclin to be considered in those at high or intermediate-high risk. Combination therapy may be poorly tolerated and less effective in patients with PAH and cardiopulmonary comorbidities. Thus, a single-agent approach with individualized decisions to add-on other PAH therapies is recommended in older patients and those with significant comorbid conditions. Management of PAH is best performed in multidisciplinary teams located in experienced centers. Other core pillars of PAH management include supportive and adjunctive treatments including oxygen, diuretics, rehabilitation, and anticoagulation in certain patients. Patients with PAH who progress despite optimal treatment or who are refractory to best medical care should be referred for lung transplantation, if eligible. Despite considerable progress, PAH is often fatal and new therapies that reverse the disease and improve outcomes are desperately needed.

Retrospective cohort study of pulmonary arterial hypertension associated with connective tissue disease effect on patients' prognosis

OBJECTIVE

The objectives of this study are to clarify clinical characteristics and recognize prognostic factors of CTD-PAH patients.

METHODS

A retrospective cohort study of consecutive patients with documented CTD-PAH diagnosis from Jan 2014 to Dec 2019 was conducted, the ones who have other comorbid conditions that cause PH were excluded. Survival functions were plotted using the Kaplan-Meier method. Univariable and multivariable Cox regression analysis was applied to determine the survival-related factors.

RESULTS

In 144 patients with CTD-PAH analyzed, the median sPAP value was 52.5 (44.0, 71.0) mmHg, the overall targeted drug usage rate was 55.6%, and only 27.5% patients were given combination. Twenty-four non-PAH-CTD patients with sPAP value were included as the control group. Compared with non-PAH-CTD groups, CTD-PAH patients had worse cardiac function, higher NT-pro BNP and γ-globulin level, and lower PaCO2 level. Compared with the mild PAH group, the moderate-severe PAH group had worse cardiac function; increased Hb, HCT, and NP-pro BNP level; and decreased PaO2. Kaplan-Meier analysis showed significant difference for survival among non-PAH-CTD, mild CTD-PAH, and moderate-severe CTD-PAH groups. The univariate analyses showed that Hb, pH, and Ln (NT-pro BNP) were identified as factors significantly associated with survival, and Hb and pH showed significant association with risk of death in the multivariate model. Kaplan-Meier analysis also showed that Hb > 109.0 g/L and pH > 7.457 affected CTD-PAH patients' survival significantly.

CONCLUSIONS

PAH is not rare in CTDs patients; PAH affects CTD patients' prognosis significantly. Higher Hb and pH were associated with an increased risk of death. Key Points • Pulmonary arterial hypertension affects connective tissue disease patients' prognosis significantly. • The significantly factors associated with survival is hemoglobin, pH, and Ln (NT-pro BNP).

Pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a rare and progressive disease characterised by remodelling of the pulmonary arteries and progressive narrowing of the pulmonary vasculature. This leads to a progressive increase in pulmonary vascular resistance and pulmonary arterial pressure and, if left untreated, to right ventricular failure and death. A correct diagnosis requires a complete work-up including right heart catheterisation performed in a specialised centre. Although our knowledge of the epidemiology, pathology and pathophysiology of the disease, as well as the development of innovative therapies, has progressed in recent decades, PAH remains a serious clinical condition. Current treatments for the disease target the three specific pathways of endothelial dysfunction that characterise PAH: the endothelin, nitric oxide and prostacyclin pathways. The current treatment algorithm is based on the assessment of severity using a multiparametric risk stratification approach at the time of diagnosis (baseline) and at regular follow-up visits. It recommends the initiation of combination therapy in PAH patients without cardiopulmonary comorbidities. The choice of therapy (dual or triple) depends on the initial severity of the condition. The main treatment goal is to achieve low-risk status. Further escalation of treatment is required if low-risk status is not achieved at subsequent follow-up assessments. In the most severe patients, who are already on maximal medical therapy, lung transplantation may be indicated. Recent advances in understanding the pathophysiology of the disease have led to the development of promising emerging therapies targeting dysfunctional pathways beyond endothelial dysfunction, including the TGF-β and PDGF pathways.

Pharmacotherapy of refractory pulmonary arterial hypertension

INTRODUCTION

Treatment of refractory pulmonary arterial hypertension (PAH) is challenging and rarely the focus of reviews. The purpose of this review is to discuss current treatment options of refractory PAH, along with the state of research of several new medications.

AREAS COVERED

We conducted a comprehensive PubMed search on the relevant literature on treating PAH, with a focus on approved and investigational interventions for high-risk patients. Our strategy used keywords 'Treatment' AND 'Pulmonary Hypertension,' without date restrictions, ensuring a thorough survey of available literature for our review.

EXPERT OPINION

By utilizing serial risk assessment to identify patients remaining intermediate or high-risk, more patients are likely to survive longer. This is done by earlier use of combination or triple therapy with prostacyclin drugs. Current medications for PAH are all essentially vasodilators that improve physiology, but do not truly modify the disease process. The potential application of new investigational medications is exciting as they work by novel pathways likely to change the landscape of refractory PAH treatment.

Impact of malnutrition on prognosis in patients with pulmonary arterial hypertension

Pulmonary arterial hypertension is a life-threatening disease that coexists with right heart failure. We evaluated the relationship between malnutrition and prognosis in patients with pulmonary arterial hypertension, as malnutrition is known as a prognosis determinant in chronic heart failure. We retrospectively reviewed data of patients with pulmonary arterial hypertension before treatment. The Geriatric Nutritional Risk Index, Prognostic Nutritional Index, and Controlling Nutritional Status scores on the day of diagnosis were calculated to assess the nutritional status. Clinical endpoints were defined as composite outcomes of all-cause death or lung transplantation. Eighty patients were enrolled (mean age, 50 years; 23 men). The mean pulmonary arterial pressure was 47 ± 19 mmHg, Geriatric Nutritional Risk Index was 99.9 ± 12.0, and Prognostic Nutritional Index was 46.3 ± 10.0. The median Controlling Nutritional Status score was 2 (1-4). During the median 5.5-year follow-up period, 28 composite events occurred. Kaplan-Meier analysis demonstrated significant differences in the incidence of clinical endpoints between groups divided by each median Geriatric Nutritional Risk Index, Prognostic Nutritional Index, and Controlling Nutritional Status score (p = 0.007, 0.039, and 0.010, respectively). In multivariate Cox regression analysis, clinical endpoints were significantly associated with Geriatric Nutritional Risk Index (hazard ratio: 0.953, 95% confidence interval: 0.918-0.990), Prognostic Nutritional Index (hazard ratio: 0.942, 95% confidence interval: 0.892-0.996), and Controlling Nutritional Status score (hazard ratio: 1.230, 95% confidence interval: 1.056-1.433) after adjustment for factors associated in univariate Cox regression analysis. Malnutrition at diagnosis is a useful prognostic predictor for patients with pulmonary arterial hypertension.

Insights into Endothelin Receptors in Pulmonary Hypertension

Pulmonary hypertension (PH) is a disease which affects the cardiopulmonary system; it is defined as a mean pulmonary artery pressure (mPAP) > 20 mmHg as measured by right heart catheterization at rest, and is caused by complex and diverse mechanisms. In response to stimuli such as hypoxia and ischemia, the expression and synthesis of endothelin (ET) increase, leading to the activation of various signaling pathways downstream of it and producing effects such as the induction of abnormal vascular proliferation during the development of the disease. This paper reviews the regulation of endothelin receptors and their pathways in normal physiological processes and disease processes, and describes the mechanistic roles of ET receptor antagonists that are currently approved and used in clinical studies. Current clinical researches on ET are focused on the development of multi-target combinations and novel delivery methods to improve efficacy and patient compliance while reducing side effects. In this review, future research directions and trends of ET targets are described, including monotherapy and precision medicine.

Pulmonary Hypertension: How to Best Treat the Different Scleroderma Phenotypes?

Pulmonary hypertension (PH) is a leading cause of morbidity and mortality in systemic sclerosis (SSc). PH is a heterogenous condition and several different forms of PH are associated with SSc, including pulmonary arterial hypertension (PAH) resulting from a pulmonary arterial vasculopathy, PH due to interstitial lung disease, PH due to left heart disease, and PH due to thromboembolic disease. Extensive research has led to an improved understanding of the mediators involved in the pathogenesis of SSc-PH. Initial combination therapy is the preferred treatment approach for SSc-PAH and requires coordinated care with a multidisciplinary team including rheumatology, pulmonology, and cardiology.

Treatment of nonarteritic anterior ischemic optic neuropathy with an endothelin antagonist: ENDOTHELION (ENDOTHELin antagonist receptor in Ischemic Optic Neuropathy)—a multicentre randomised controlled trial protocol

Background

Nonarteritic anterior ischemic optic neuropathy (NAAION) is a major cause of blindness in individuals over 50 years of age, with no available effective treatment. The oral dual endothelin receptor antagonist, bosentan, increases retinal optic nerve head blood flow in healthy humans and glaucoma patients. The objective of this trial is to assess the efficacy of bosentan administered at the acute stage in improving outcomes in NAAION patients.

Methods

ENDOTHELION (ENDOTHELin antagonist receptor in Ischemic Optic Neuropathy) is a phase III, interventional, prospective, multicentre, placebo-controlled randomised double-blind clinical trial. The primary outcome is change in the visual field mean deviation (MD) at 3 months (Humphrey 30-2 SITA standard programme). Secondary outcomes include MD and visual acuity changes up to 24 months, changes in peripapillary retinal nerve fibre and macular ganglion cell layer thickness in the affected eye, as measured by optical coherence tomography, rate of NAAION bilateralisation at 2 years, and quality-of-life. Patients over 50 years of age presenting with typical NAAION of recent onset (less than 21 days) are randomly assigned to either 125 mg oral bosentan or placebo, twice a day, during 8 weeks. Besides visits during the treatment phase, patients attend follow-up visits at 2, 3, 6, 12 and 24 months. The inclusion of patients began in August 2015 at five French University hospital ophthalmology departments and two specialised ophthalmology centres. It is planned to include 86 patients in this trial. To date we have included 72 patients and 49 have completed the full follow-up process.

Discussion

An endothelin receptor antagonist is a potential approach to improving the anatomical and functional prognosis of patients with NAAION. This multicentre double-blind randomised controlled trial is an opportunity to assess (1) the effect of bosentan on the structure and function of the optic nerve in NAAION, at 3 months, (2) the effect of bosentan on the bilateralisation rate at 24 months and (3) the tolerance profile of bosentan in this population.

Trial registration

ClinicalTrials.gov NCT02377271. Registered on March 3, 2015.

Pharmacological counseling in hepatotoxicity induced by macitentan and selexipag: a case report

Background

Pulmonary arterial hypertension is a progressive, debilitating condition characterized by increased resistance in the pulmonary arterial circulation. Current treatments for pulmonary arterial hypertension include endothelin receptor antagonists such as bosentan, sitaxentan, ambrisentan, macitentan, and oral prostacyclin receptor agonists such as selexipag. Endothelin receptor antagonists have been associated with liver injury, while hepatotoxicity was not reported for selexipag. Although genetic variability has been indisputably associated with variability in drug response, no study has been designed until now to assess its effects on the pharmacokinetics of endothelin receptor antagonists or selexipag.

Case presentation

We report the case of a 58-year-old female Caucasian patient with a dramatic increase in plasma levels of transaminases after treatment with macitentan and selexipag, drugs whose risk of causing liver injury has so far been considered limited. After therapy discontinuation, plasma levels of transaminases returned to baseline, thus suggesting a role of these drugs in the observed hepatotoxicity. After pharmacological counseling, we decided to introduce ambrisentan for the patient’s treatment. After 7 months of treatment, no liver injury has been reported. To evaluate the role of genetic factors in the observed hepatotoxicity, we genotyped the patient for single-nucleotide polymorphisms previously associated with macitentan, ambrisentan, or selexipag metabolism. We found a genetic profile associated with a poor metabolizer (PM) phenotype for CYP2C8 and CYP2C9, key enzymes for elimination of both macitentan and selexipag. The reported results suggest that an allelic profile associated with low activity for CYP2C8 and CYP2C9 enzyme could be a potential risk factor for macitentan and selexipag-induced liver injury and could provide a possible marker for early identification of subjects at higher risk of developing hepatotoxicity.

Conclusions

A multidisciplinary approach based on clinical evaluation, as well as pharmacological counseling and evaluation of the patient’s genetic profile, might be useful for identification of patients with a high chance of drug-induced liver injury, avoiding unnecessary risks in therapy selection and prescription.

Inhibition of KIF23 Alleviates IPAH by Targeting Pyroptosis and Proliferation of PASMCs

Idiopathic pulmonary arterial hypertension (IPAH) is a progressive vascular disease with high mortality and heritability. Pyroptosis is a novel form of programmed cell death, and it is closely associated with IPAH. However, the roles of pyroptosis-related genes (PRGs) in IPAH are still largely unknown. In this study, we identified KIF23 as the most relevant gene for IPAH and pyroptosis, and its expression was significantly increased in pulmonary arterial smooth muscle cells (PASMCs) of IPAH. Besides, the pyroptosis level of PASMCs was also considerably upregulated in IPAH. Knockdown of KIF23 in PASMCs could significantly suppress the PASMCs’ pyroptosis and proliferation and then alleviate the increase in pulmonary arterial pressure, right ventricular hypertrophy, and pulmonary vascular resistance in IPAH. KIF23 regulated the expression of Caspase3, NLRP3, and HMGB1, and they were all involved in the PI3K/AKT and MAPK pathways, indicating that PI3K/AKT and MAPK pathways might participate in regulating PASMCs pyroptosis by KIF23. In conclusion, our study suggests that KIF23 may be a new therapeutic target for IPAH, which can alleviate the symptoms of IPAH by inhibiting the pyroptosis and proliferation of PASMCs.

Efficacy and safety of bosentan in the treatment of persistent pulmonary hypertension of the newborn: a Metaanalysis

OBJECTIVES

To systematically evaluate the efficacy and safety of bosentan in the treatment of persistent pulmonary hypertension of the newborn (PPHN).

METHODS

Chinese Journal Full-text Database, Weipu Database, Wanfang Data, China Biology Medicine disc, PubMed, Web of Science, Embase, and Cochrane Library were searched for literature on bosentan in the treatment of PPHN published up to August 31, 2021.

RESULTS

A total of 8 randomized controlled trials were included for Meta analysis. The results of the Meta analysis showed that compared with the control group, the bosentan treatment group had a significantly lower treatment failure rate (RR=0.23, P<0.001), a significantly greater reduction in pulmonary artery pressure [mean difference (MD)=-11.79, P<0.001)], significantly greater increases in oxygen partial pressure (MD=10.21, P=0.006) and blood oxygen saturation (MD=8.30, P<0.001), and a significantly shorter length of hospital stay (MD=-1.35, P<0.001). The descriptive analysis showed that the bosentan treatment group had a lower degree of tricuspid regurgitation than the control group after treatment. The main adverse reactions of bosentan treatment included abnormal liver function, anemia and edema. The results of subgroup analysis based on treatment regimen, research area, and drug dose were consistent with those before stratification.

CONCLUSIONS

Bosentan is effective in the treatment of PPHN. However, when using bosentan, attention should be paid to adverse reactions such as abnormal liver function.

A narrative review on adverse effects of dasatinib with a focus on pharmacotherapy of dasatinib-induced pulmonary toxicities

Chronic myeloid leukemia (CML), a myeloproliferative disorder caused by the over activity of BCR-ABL1 (breakpoint cluster region-Abelson), has been successfully treated by Tyrosine kinase inhibitors (TKIs). While imatinib is known as the first-line treatment of CML, in some cases other TKIs including dasatinib, nilotinib, bosutinib, and ponatinib may be preferred. Dasatinib, a second-generation TKI, inhibits multiple family kinases including BCR-ABL, SRC family kinases, receptor kinases, and TEC family kinases. It is effective against most imatinib-resistant cases except T315I mutation. Despite the superiority of dasatinib in its hematologic and cytogenetic responses in CML compared to imatinib, its potentially harmful pulmonary complications including pleural effusion (PE) and pulmonary arterial hypertension (PAH) may limit its use. Appropriate management of these serious adverse reactions is critical in both improving the quality of life and the outcome of the patient. In this narrative review, we will scrutinize the pulmonary complications of dasatinib and focus on the management of these toxicities.

Update on Medical Management of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension is a rare disease characterized by pulmonary microvasculature remodeling leading to right ventricular failure and death. Medical management of pulmonary hypertension has grown increasingly complex as more therapeutic agents have been developed. Evolving treatment strategies leveraging the endothelin, nitric oxide, and prostacyclin pathways lead to improved exercise capacity and outcomes in patients; however, significant opportunities for advancement remain.

Therapy for Pulmonary Arterial Hypertension: Glance on Nitric Oxide Pathway

Pulmonary arterial hypertension (PAH) is a severe disease with a resultant increase of the mean pulmonary arterial pressure, right ventricular hypertrophy and eventual death. Research in recent years has produced various therapeutic options for its clinical management but the high mortality even under treatment remains a big challenge attributed to the complex pathophysiology. Studies from clinical and non-clinical experiments have revealed that the nitric oxide (NO) pathway is one of the key pathways underlying the pathophysiology of PAH. Many of the essential drugs used in the management of PAH act on this pathway highlighting its significant role in PAH. Meanwhile, several novel compounds targeting on NO pathway exhibits great potential to become future therapy medications. Furthermore, the NO pathway is found to interact with other crucial pathways. Understanding such interactions could be helpful in the discovery of new drug that provide better clinical outcomes.

Bosentan Alters Endo- and Exogenous Bile Salt Disposition in Sandwich-Cultured Human Hepatocytes

Bosentan, a well-known cholestatic agent, was not identified as cholestatic at concentrations up to 200 µM based on the drug-induced cholestasis (DIC) index value, determined in a sandwich-cultured human hepatocyte (SCHH)-based DIC assay. To obtain further quantitative insights into the effects of bosentan on cellular bile salt handling by human hepatocytes, the present study determined the effect of 2.5-25 µM bosentan on endogenous bile salt levels and on the disposition of 10 µM chenodeoxycholic acid (CDCA) added to the medium in SCHHs. Bosentan reduced intracellular as well as extracellular concentrations of both endogenous glycochenodeoxycholic acid (GCDCA) and glycocholic acid in a concentration-dependent manner. When exposed to 10 µM CDCA, bosentan caused a shift from canalicular efflux to sinusoidal efflux of GCDCA. CDCA levels were not affected. Our mechanistic model confirmed the inhibitory effect of bosentan on canalicular GCDCA clearance. Moreover, our results in SCHHs also indicated reduced GCDCA formation. We confirmed the direct inhibitory effect of bosentan on CDCA conjugation with glycine in incubations with liver S9 fraction. SIGNIFICANCE STATEMENT: Bosentan was evaluated at therapeutically relevant concentrations (2.5-25 µM) in sandwich-cultured human hepatocytes. It altered bile salt disposition and inhibited canalicular secretion of glycochenodeoxycholic acid (GCDCA). Within 24 hours, bosentan caused a shift from canalicular to sinusoidal efflux of GCDCA. These results also indicated reduced GCDCA formation. This study confirmed a direct effect of bosentan on chenodeoxycholic acid conjugation with glycine in liver S9 fraction.

Comparative assessment of efficacy and safety of ambrisentan and bosentan in patients with pulmonary arterial hypertension: A meta-analysis

WHAT IS KNOWN AND OBJECTIVE

Two endothelin receptor antagonists, ambrisentan and bosentan, have been demonstrated to be effective individually compared with placebo in the treatment of patients with pulmonary arterial hypertension (PAH). This network meta-analysis compared the efficacy and safety of ambrisentan and bosentan in patients with PAH.

METHODS

Clinical trials were identified from the Cochrane Central Register of Controlled Trials (CENTRAL/CCTR), EMBASE and PubMed databases. Weighted mean differences (MD) with 95% confidence intervals (CI) were calculated for continuous outcomes (6-min walk distance [6MWD] and Borg dyspnoea index [BDI]). Hazard ratio (HR) was calculated for binary outcomes, including clinical worsening, discontinuation due to adverse events (AEs) and liver dysfunction. Surface under cumulative ranking curve (SUCRA) was used to rank the treatments in each index.

RESULTS

Five clinical trials from four published studies (total patients: n = 920) were included. Ambrisentan and bosentan showed no significant difference in 6MWD (MD: -1.32; 95% CI: -27.87, 25.31, SUCRA score: ambrisentan 0.73, bosentan 0.77), BDI (MD: -0.16; 95% CI: -0.98, 0.65, SUCRA score: ambrisentan 0.83, bosentan 0.66), clinical worsening (HR: 0.99; 95% CI: 0.33, 2.94, SUCRA score: ambrisentan 0.75, bosentan 0.74) and discontinuation due to AEs (HR: 0.84; 95% CI: 0.11, 5.86, SUCRA score: ambrisentan 0.47, bosentan 0.57). However, ambrisentan was significantly better than bosentan with respect to abnormal liver function (HR: 23.18; 95% CI: 2.24, 377.20, SUCRA score: ambrisentan 0.99, bosentan 0.02).

WHAT IS NEW AND CONCLUSION

The results of this network meta-analysis suggest that ambrisentan was similar to bosentan in efficacy, while it exhibited better tolerability with respect to abnormal liver function in comparison with bosentan, in patients with PAH.

Synergic effect of atorvastatin and ambrisentan on sinusoidal and hemodynamic alterations in a rat model of NASH

In non-alcoholic steatohepatitis (NASH), decreased nitric oxide and increased endothelin-1 (ET-1, also known as EDN1) released by sinusoidal endothelial cells (LSEC) induce hepatic stellate cell (HSC) contraction and contribute to portal hypertension (PH). Statins improve LSEC function, and ambrisentan is a selective endothelin-receptor-A antagonist. We aimed to analyse the combined effects of atorvastatin and ambrisentan on liver histopathology and hemodynamics, together with assessing the underlying mechanism in a rat NASH model. Diet-induced NASH rats were treated with atorvastatin (10 mg/kg/day), ambrisentan (30 mg/kg/day or 2 mg/kg/day) or a combination of both for 2 weeks. Hemodynamic parameters were registered and liver histology and serum biochemical determinations analysed. Expression of proteins were studied by immunoblotting. Conditioned media experiments were performed with LSEC. HSCs were characterized by RT-PCR, and a collagen lattice contraction assay was performed. Atorvastatin and ambrisentan act synergistically in combination to completely normalize liver hemodynamics and reverse histological NASH by 75%. Atorvastatin reversed the sinusoidal contractile phenotype, thus improving endothelial function, whereas ambrisentan prevented the contractile response in HSCs by blocking ET-1 response. Additionally, ambrisentan also increased eNOS (also known as Nos3) phosphorylation levels in LSEC, via facilitating the stimulation of endothelin-receptor-B in these cells. Furthermore, the serum alanine aminotransferase of the combined treatment group decreased to normal levels, and this group exhibited a restoration of the HSC quiescent phenotype. The combination of atorvastatin and ambrisentan remarkably improves liver histology and PH in a diet-induced NASH model. By recovering LSEC function, together with inhibiting the activation and contraction of HSC, this combined treatment may be an effective treatment for NASH patients.

Summary: Combining atorvastatin with ambrisentan is safe and effective in reducing intrahepatic resistance and portal hypertension in an experimental model of NASH. This liver histology amelioration highlights a promising therapeutic strategy.

Bosentan-induced immune hemolytic anemia in 17 years old man. A case report

Hemolytic anemia is a very important immune-mediated reaction, which its late diagnosis can be fatal. Medications along with other causes can induce hemolytic anemia. Drug induced immune hemolytic anemia (DIIHA) is caused by the development of autoantibodies. Accordingly, DIIHA is rare and there is not enough data for its prevalence. Number of drugs that can cause DIIHA have increased in recent decades. A 17-year-old man who had congenital single ventricle heart (CHB) and pulmonary artery hypertension (PAH) was admitted at Imam Khomeini hospital complex affiliated to Tehran University of Medical Sciences, with chief complaint of jaundice and icter. Bosentan and Tadalafil were in the list of the drugs used by this patient. Although both drugs were recommended to be discontinued in the patient, in the course of hospitalization, the patient accidentally continued to take his Tadalafil. However, the patient's recovery continued. Given that the patient's Coombs test was positive, his hemolytic anemia mechanism was drug-induced immune-mediated hemolytic anemia. As a result, according to Naranjo score = 6, Bosentan was considered as the main possible culprit to induce DIIHA in this patient. Following the discontinuation of Bosentan and receiving Prednisolone, the patient's clinical symptoms and laboratory parameters resolved and the patient was then discharged.

Oral drugs used to treat persistent pulmonary hypertension of the newborn

Introduction:Persistent Pulmonary Hypertension of the Newborn (PPHN) is a life-threatening neonatal condition, mostly treated with inhaled nitric oxide (iNO), intravenous prostaglandins, oral bosentan, sildenafil and tadalafil. However, the utility of non-oral agents is limited in PPHN for their side effects and inconvenient deliveries. Therefore, oral agents such as bosentan, sildenafil and tadalafil are becoming appealing for their satisfactory efficacy, easy mode of administration and acceptable side effects. Areas covered: We conducted a comprehensive search on Pubmed, Scopus, Web of Sciences concerning the use of bosentan, sildenafil and tadalafil to treat PPHN and summarized their efficacy, safety and pharmacokinetics. Expert opinion: Current randomized controlled trials (RCTs) have demonstrated the favorable responses and tolerable side effects of bosentan and sildenafil. Nevertheless, those RCTs are small and only one study has described the pharmacokinetics of sildenafil in neonates. Accordingly, bosentan, sildenafil and tadalafil remain off-label in clinical use. More well-designed RCTs with large samples and long-term follow-up and pharmacometrics studies are needed to demonstrate the efficacy, safety and pharmacokinetics of bosentan, sildenafil and tadalafil in PPHN.

Chondroitin sulfate mediates liver responses to injury induced by dual endothelin receptor inhibition

Although dual endothelin receptor antagonists (ERAs) show great promise for treating various conditions, their propensity to induce liver injury limits their clinical usage. Inflammation and fibrosis are important processes in liver responses to injury and it has been suggested that they and dual ERA-induced liver injury are mediated by the proteoglycan component chondroitin sulfate (CS), which is synthesized by CHST3 and CHST13. In this study, we investigated whether dual ER inhibition in the liver could alter CHST3 and CHST13 expression and thus CS production and whether liver CS content could prevent inflammatory and fibrosis responses after liver injury. We observed increased CHST3 and CHST13 expression after liver injury in bile duct ligated mice and histologically confirmed abundant CS deposition in the injured liver. Moreover, treating Hep3B cells with a dual ERA mimic significantly increased CHST3 and CHST13 expression, inflammatory cytokine levels, and glycosaminoglycan deposition. Furthermore, pro-inflammatory and pro-fibrotic markers were observed after dual ERA treatment, while treatment with CS-degrading chondroitinase ABC was able to successfully reverse these phenotypes. These observations suggest that CHST3- and CHST13-induced CS production can mediate liver injury responses caused by dual ER inhibition and thus could be an alternative pathway for treating ERA-induced liver injury.

Predictive model of bosentan-induced liver toxicity in Japanese patients with pulmonary arterial hypertension

Bosentan, an endothelin receptor antagonist, has been widely used as a first-line medication for the treatment of pulmonary arterial hypertension (PAH). It has been shown to improve symptoms of hypertension, exercise capacity, and hemodynamics and prolong time to clinical worsening. However, liver dysfunction is a major side effect of bosentan treatment that could hamper the optimal management of patients with PAH. Previously, we demonstrated, using drug metabolism enzymes and transporters analysis, that the carbohydrate sulfotransferase 3 (CHST3) and CHST13 alleles are significantly more frequent in patients with elevated aminotransferases during therapy with bosentan than they are in patients without liver toxicity. In addition, we constructed a pharmacogenomics model to predict bosentan-induced liver injury in patients with PAH using two single-nucleotide polymorphisms and two nongenetic factors. The purpose of the present study was to externally validate the predictive model of bosentan-induced liver toxicity in Japanese patients. We evaluated five cases of patients treated with bosentan, and one presented with liver dysfunction. We applied mutation alleles of CHST3 and CHST13, serum creatinine, and age to our model to predict liver dysfunction. The sensitivity and specificity were calculated as 100% and 50%, respectively. Considering that PAH is a rare disease, multicenter collaboration would be necessary to validate our model.

Pulmonary arterial hypertension specific therapy: The old and the new

Pulmonary arterial hypertension (PAH) is a vascular disorder associated with high morbidity and mortality rate and is characterized by pulmonary vascular remodeling and increased pulmonary vascular resistance, ultimately resulting in right ventricular failure and death. Over the past few decades, significant advances in the understanding of the epidemiology, pathogenesis, and pathophysiology of pulmonary arterial hypertension have occured. This has led to the development of disease specific treatment including prostanoids, endothelin receptor antagonists, phosphodiesterase inhibitors, and soluble guanylate cyclase stimulators. These therapies significantly improve exercise capacity, quality of life, pulmonary hemodynamics, but none of the current treatments are actually curative and long-term prognosis remains poor. Thus, there is a clear need to develop new therapies. Several potential pharmacologic agents for the treatment of pulmonary arterial hypertension are under clinical development and some promising results with these treatments have been reported. These agents include tyrosine protein kinase inhibitors, rho-kinase inhibitors, synthetically produced vasoactive intestinal peptide, antagonists of the 5-HT2 receptors, and others. This article will review several of these promising new therapies and will discuss the current evidence regarding their potential benefit in pulmonary arterial hypertension.

Learning from registries in pulmonary arterial hypertension: pitfalls and recommendations

Pulmonary arterial hypertension is a rare and incurable chronic disease characterised by a progressive increase in pulmonary vascular resistance and right heart failure. Patient registries collecting observational data can be of great value in the understanding of clinical problems. While clinical trials provide data in selected patient populations, registries better depict real-life practice. This review aims to reflect the input of patient registries in the general knowledge of the disease. Advances in epidemiology of the different subgroups, including data on incidence and/or prevalence, increasing age at presentation and stagnating diagnostic delay are reported. The importance of haemodynamic definition criteria and cardiac comorbidities are underscored. The review also shows the major transformation that pulmonary arterial hypertension therapeutic management has undergone, with still insufficient use of combination therapies; consecutive improvement in outcome; upcoming evidence in disfavour of anticoagulation; and validity of the available risk-stratification tools derived from large registries. Product registries are also briefly presented. Finally, the benefits of registries and methodological aspects are discussed, including immortal time bias, registry data quality and recommendations from EU organisations (EUCERD and PARENT).

Prediction of Drug-Induced Hepatotoxicity Using Long-Term Stable Primary Hepatic 3D Spheroid Cultures in Chemically Defined Conditions

High failure rates of drug candidates in the clinics, restricted-use warnings as well as withdrawals of drugs in postmarketing stages are of substantial concern for the pharmaceutical industry and drug-induced liver injury (DILI) constitutes one of the most frequent reasons for such safety failures. Importantly, as DILI cannot be accurately predicted using animal models, animal safety tests are commonly complemented with assessments in human in vitro systems. 3D spheroid cultures of primary human hepatocytes in chemically defined conditions, hereafter termed CD-spheroids, have recently emerged as a microphysiological model system in which hepatocytes retain their molecular phenotypes and hepatic functions for multiple weeks in culture. However, their predictive power for the detection of hepatotoxic liabilities has not been systematically assessed. Therefore, we here evaluated the hepatotoxicity of 123 drugs with or without direct implication in clinical DILI events. Importantly, using ATP quantifications as the single endpoint, the model accurately distinguished between hepatotoxic and nontoxic structural analogues and exceeded both sensitivity and specificity of all previously published in vitro assays at substantially lower exposure levels, successfully detecting 69% of all hepatotoxic compounds without producing any false positive results (100% specificity). Furthermore, the platform supports the culture of spheroids of primary hepatocytes from preclinical animal models, thereby allowing the identification of animal-specific toxicity events. We anticipate that CD-spheroids represent a powerful and versatile tool in drug discovery and preclinical drug development that can reliably flag hepatotoxic drug candidates and provide guidance for the selection of the most suitable animal models.

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

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

Chronic Right Heart Failure: Expanding Prevalence and Challenges in Outpatient Management

Right heart failure is caused by right heart dysfunction resulting in suboptimal stroke volume to supply the pulmonary circulation. Therapeutic developments mean that patients with acute right heart failure survive to hospital discharge and live with chronic right heart failure. Chronic right heart failure management aims to reduce afterload, optimize preload, and support contractility, with the best evidence available in vascular targeted therapy for pulmonary arterial hypertension. However, the management of chronic right heart failure relies on adapting therapies for left ventricular heart failure to the right. We review right heart failure management in the ambulatory setting and its challenges.

CHST3 and CHST13 polymorphisms as predictors of bosentan-induced liver toxicity in Japanese patients with pulmonary arterial hypertension

Bosentan, an endothelin receptor antagonist, has been widely used as a first-line drug for the treatment of pulmonary arterial hypertension (PAH). In addition, bosentan is approved for patients with digital ulcers related to systemic sclerosis. Liver dysfunction is a major adverse effect of bosentan and may lead to discontinuation of therapy. The purpose of this study was to identify genomic biomarkers to predict bosentan-induced liver injury. A total of 69 PAH patients were recruited into the study. An exploratory analysis of 1936 single-nucleotide polymorphisms (SNPs) in 231 genes involved in absorption, distribution, metabolism, and elimination of multiple medications using Affimetrix DMET™ (Drug Metabolism Enzymes and Transporters) chips was performed. We extracted 16 SNPs (P <  0.05) using the Jonckheere-Terpstra trend test and multiplex logistic analysis; we identified two SNPs in two genes, CHST3 and CHST13, which are responsible for proteoglycan sulfation and were significantly associated with bosentan-induced liver injury. We constructed a predictive model for bosentan-induced liver injury (area under the curve [AUC]: 0.89, sensitivity: 82.61%, specificity: 86.05%) via receiver operating curve (ROC) analysis using 2 SNPs and 2 non-genetic factors. Two SNPs were identified as potential predictive markers for bosentan-induced liver injury in Japanese patients with pulmonary arterial hypertension. This is the first pharmacogenomics study linking proteoglycan sulfating genes to drug-induced liver dysfunction, a frequently observed clinical adverse effect of bosentan therapy. These results may provide a way to personalize PAH medicine as well as provide novel mechanistic insights to drug-induced liver dysfunction.

Hepatic safety of ambrisentan alone and in combination with tadalafil: a post-hoc analysis of the AMBITION trial

Treatment with endothelin receptor antagonists (ERA) can result in adverse hepatic effects in patients with pulmonary arterial hypertension (PAH). We evaluated the hepatic safety of ambrisentan (ABS), an ERA, used as monotherapy, or with tadalafil (TAD), a phosphodiesterase-5 (PDE5) inhibitor as initial combination therapy (ABS + TAD) in the AMBITION trial. This was a retrospective analysis set in academic and private outpatient clinics and research centers. This analysis included 596 patients with PAH who were randomized to ABS or TAD as monotherapy or ABS + TAD as initial combination therapy and received at least one dose of study drug, and who had baseline and follow-up hepatic function data. Treatment options following a clinical failure event included blinded combination therapy (BCT). The proportion of patients with elevations in alanine or aspartate aminotransferases (ALT/AST) > 3 × upper limit of normal (ULN), and those with total bilirubin (TBili) > 2× ULN and ALT or AST > 3 × ULN (referred to as potential Hy’s law), were determined before BCT as well as including time on BCT. Elevations in ALT/AST > 3 × ULN during the study were in the range of 3.4–3.7%, with an annualized incidence of 2.1–2.93%. The majority of patients with elevations in ALT/AST had elevations > 3 to ≤ 5 × ULN. Three patients (0.5%) had ALT/AST > 3 × ULN plus TBili > 2 × ULN. All three patients had probable alternative causes (cardiogenic shock, liver metastases, lymphoma) for the elevations. Our analysis of the AMBITION trial demonstrated that ABS and ABS + TAD were not associated with drug-induced liver injury.

Bosentan therapy for pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension: A systemic review and meta-analysis

BACKGROUND AND OBJECTIVE

Bosentan therapy has been recommended for pulmonary arterial hypertension (PAH) and might be beneficial for chronic thromboembolic pulmonary hypertension (CTEPH). We aimed to evaluate the specific effects of bosentan for PAH and CTEPH.

MATERIALS AND METHODS

We performed a systemic review and meta-analysis of randomized controlled trials (RCTs), comparing efficacy and safety of bosentan treatment for PAH and CTEPH through major biomedical database.

RESULTS

A total of 10 RCTs including 1185 patients were enrolled. For PAH patients, bosentan prolonged 6-minute walk distance with a weighted mean difference of 35.7 m, reduced mean pulmonary arterial pressure by 5.7 mm Hg, increased cardiac index by 0.4 L/min/m2 , reduced pulmonary vascular resistance by 305.1 dyn·s/cm5 , prevented functional class from deterioration and reduced clinical worsening as compared with placebo. For CTEPH patients, bosentan improved cardiac index by 0.3 L/min/m2 and reduced pulmonary vascular resistance by 176.0 dyn·s/cm5 . Other efficacy outcomes regarding CTEPH did not attain statistical difference. For both PAH and CTEPH, there was no significant difference in mortality or adverse event between bosentan and placebo group. However, bosentan raised the risk of abnormal liver function in both PAH and CTEPH patients.

CONCLUSIONS

Bosentan is effective in treating PAH, whereas it improves only certain hemodynamic parameters of CTEPH. Incidence of liver function abnormality is higher in bosentan treatment.

Prevalence of primary Sjögren's syndrome in patients undergoing evaluation for pulmonary arterial hypertension

Background

The prevalence of pulmonary arterial hypertension (PAH) in primary Sjögren’s syndrome (SS) had been reported to be rare. However, recent studies using echocardiography as a screening method showed conflicting results, and the true prevalence is still unclear. Since diagnosing primary SS is difficult because of its heterogeneous nature, a number of patients with primary-SS-associated PAH may be misdiagnosed with idiopathic PAH, losing their chance to undergo immunosuppressive therapy. Therefore, we sought to elucidate the prevalence of primary SS among patients who initially present with PAH.

Methods

From our prospective institutional PAH database, 40 consecutive patients without any obvious cause of PAH at the time of PAH diagnosis were identified. We retrospectively evaluated the prevalence of primary SS diagnosed during or after the initial assessment of PAH.

Results

During the initial assessment, one patient was diagnosed with primary-SS-associated PAH. Among the 25 patients who were initially diagnosed with idiopathic PAH, five were diagnosed with primary SS during their course of the disease. Of the five patients, three had key signs suggesting primary SS and were probably underdiagnosed at the time of initial evaluation. The remaining two patients, who were finally diagnosed with primary SS, did not have any specific signs suggesting primary SS at the time of initial evaluation but showed positive conversion of their autoantibodies during the course of PAH.

Conclusion

The prevalence of primary-SS-associated PAH may be relatively high among patients who undergo initial evaluation for PAH. Furthermore, primary-SS-associated PAH may be underdiagnosed with routine evaluation for the primary cause of PAH. Clinicians should pay specific attention and carefully evaluate the possibility of primary SS in patients with PAH.

The efficiency of endothelin receptor antagonist bosentan for pulmonary arterial hypertension associated with congenital heart disease: A systematic review and meta-analysis

BACKGROUND

Oral bosentan has been widely applied in pulmonary arterial hypertension associated with congenital heart disease (PAH-CHD). A systemic review and meta-analysis was conducted for a therapeutic evaluation of oral bosentan in both adult and pediatric patients with PAH-CHD. The acute responses and a long-term effect were respectively assessed in a comparison with baseline characteristics, and the improvement of exercise tolerance was analyzed.

METHODS

PubMed, Medline, Embase, and Cochrane Central Register of clinical controlled trails or observational studies have been searched for a recording of bosentan effects on the PAH-CHD participants. For mortality and rate of adverse events (AEs), it was described in detail. Randomized-effects model or fixed-effects model was used to calculate different effective values with a sensitivity analysis.

RESULTS

Seventeen studies were pooled in this review, and 3 studies enrolled the pediatric patients. Among all studies, 456 patients were diagnosed with PAH-CHD, and 91.7% were treated with oral bosentan. With a term less than 6 months of bosentan therapy, there existed a significant improvement in 6-minute walk distance (6MWD) and the World Health Organization functional class (WHO-FC), but no such differences in Borg dyspnea index scores (BDIs) and the resting oxygen saturation (SpO2). Although with a prolonged treatment, not only 6MWD and FC, but also the resting SpO2 and heart rate were changed for a better exercise capability. Additionally, compared with the basic cardiopulmonary hemodynamics, it showed a statistically significant difference in mean pulmonary arterial pressure (mPAP) and pulmonary vascular resistance index (PVRi). Although a limitation of pooled studies with comparative outcomes of different terms, outcomes presented a lower WHO-FC which contributes to a success in a prolonged treatment.

CONCLUSIONS

Bosentan in PAH-CHD is well established and still requires clinical trials for an identification of its efficiency on CHD patients for an optimized period lessening a serious complication and the common AEs.

Risk Evaluation and Mitigation Strategies (REMSs): Are They Improving Drug Safety? A Critical Review of REMSs Requiring Elements to Assure Safe Use (ETASU)

Risk Evaluation and Mitigation Strategies (REMSs) with Elements to Assure Safe Use (ETASU) are requested for drugs with significant safety risks. We reviewed REMS programs issued since 2011 to evaluate their rationales, characteristics, and consistencies, and evaluated their impact on improving drug safety. We conducted a literature search and a survey of relevant websites (FDA, manufacturers, and REMSs). ETASU characteristics were summarized. REMS risks were compared with labeled risks, including black box warnings. Forty-two programs were analyzed. Seven incorporated drugs of the same class. Most drugs (57%) were indicated for an orphan disease. A single risk was mentioned in 24 REMSs, and multiple risks in 18. Embryo-fetal toxicity and abuse or misuse were the most frequent risks. All risks were identified during clinical development but some were hypothetical. Thirty-six drugs had a black box warning. REMS risks and black box risks differed for 11 drugs. A drug with multiple indications could have a REMS for one of them but not for another. Most REMSs required prescriber training and certification, half required dispenser certification and patient enrolment. REMSs were revised multiple times and only three (7%) were discontinued. No data were available to establish whether REMSs were effective in improving drug safety. Some REMSs were deemed inefficient. REMSs with ETASU continue to be implemented but their impact on improving drug safety is still not documented. Hence, one of the main requirements of the FDA Amendments Act of 2007 is not being addressed. In addition, REMSs are complex and their logic is inconsistent; we recommend a thorough re-evaluation of the REMS program.

Protective effects of PPAR-γ against pregnancy-induced hypertension by differential ETR expression in rat models

This study aims to investigate the effects of PPAR-γ on rats with pregnancy-induced hypertension (PIH) by regulating endothelin receptor (ETR). A total of 60 pregnant Wistar rats were selected, and 50 rats were used to establish endotoxin induced PIH rat models. Rats were equally assigned into PIH-NS, PIH-5 mg/kg RM, PIH-10 mg/kg RM, PIH-100 mg/kg ETR, and PIH-200 mg/kg ETR groups, and the rest 10 rats were assigned to a the control group. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blotting were used for determining mRNA and protein expressions of PPAR-γ and ET_A R, respectively. Protein expression of ET-1 was detected by immunohistochemistry. Results show that On the 22nd day of pregnancy, compared with the PIH-NS group, SBP decreased in other groups, and platelet concentration increased most significantly in the PIH-10 mg/kg RM and PIH-200 mg/kg ETR groups. Compared with the control, PIH-10 mg/kg RM and PIH-200 mg/kg ETR groups, the increase in the expression of ET-1 and ET_A R was most significant in the PIH-NS group. Compared with the control and PIH-10 mg/kg RM groups, expression of PPAR-γ was lower in the PIH-NS, PIH-5 mg/kg RM, PIH-100 mg/kg ETR, and PIH-200 mg/kg ETR groups. Compared with the PIH-NS, PIH-100 mg/kg ETR and PIH-200 mg/kg ETR groups, PPAR-γ expression was significantly higher in the PIH-5 mg/kg RM group (all P < 0.05). Based on our findings, we conclude that PPAR-γ activation inhibits ETR expression and reduces the effect of ET-1 on vascular contraction thereby delaying PIH progression.

Treatment of Persistent Pulmonary Hypertension of the Newborn: Use of Pulmonary Vasodilators in Term Neonates

Persistent pulmonary hypertension of the newborn (PPHN) represents a challenging condition associated with significant morbidity. A successful transition from intrauterine to extrauterine life is contingent on adequate pulmonary vasodilation. Several pathophysiologies contribute to the failure of this cascade and may result in life-threatening hypoxia and acidosis in the newborn. Management includes optimal respiratory support, adequate sedation and analgesia, and support of vascular tone and cardiac function. Pulmonary vasodilation has the potential to overcome the cycle of hypoxia and acidosis, improving outcome in these infants. Oxygen and inhaled nitric oxide represent the foundation of therapy. Tertiary pulmonary vasodilators represent a greater challenge, selecting between therapies that include prostanoids, sildenafil, and milrinone. Variable levels of evidence exist for each agent. Thorough review of available data informing efficacy and adverse effects contributes to the development of an informed approach to neonates with refractory PPHN.