lu-208075 and macitentan

Pediatric pulmonary hypertension (PAH) is a rare disease that carries a poor prognosis if left untreated. Although there are published guidelines for the treatment of children with pulmonary hypertension, due to the limited number of robust pediatric clinical trials, recommendations are often based on limited data or clinical experience. Furthermore, many practical aspects of care, particularly for the pediatric patient, are learned through experience and best navigated with a multidisciplinary team. While newer PAH therapies have been approved for adults, there is still limited but expanding experience in pediatrics. This new information will help improve the targets of goal-oriented therapy. Lastly, this review highlights practical aspects in the use of the different therapies available for the treatment of pediatric pulmonary hypertension.

Topics: Adolescent; Adult; Bosentan; Calcium Channel Blockers; Child; Child, Preschool; Epoprostenol; Familial Primary Pulmonary Hypertension; Humans; Hypertension, Pulmonary; Iloprost; Infant; Infant, Newborn; Phenotype; Phenylpropionates; Phosphodiesterase 5 Inhibitors; Prognosis; Pulmonary Arterial Hypertension; Pyridazines; Pyrimidines; Receptors, Endothelin; Sildenafil Citrate; Sulfonamides; Tadalafil; Young Adult

It is commonly reported a limitation of therapeutic strategy in Eisenmenger syndrome (ES) historically. This qualitative systematic review is conducted to evaluate the safety and efficacy of pulmonary arterial hypertension-specific drug therapy (PAH-SDT) for ES patients for a clinical therapeutic strategy based on evidence.. PubMed, EMBASE, and the Cochrane Library databases have been systematically reviewed up to January 2019. Two reviewers independently conducted a literature search, quality evaluation, and data extraction. The occurrence of death, deterioration, and adverse events (AEs) has respectively been described as a count or percentage. Meta-analysis was conducted by Stata 15.1, and weighted mean differences (WMD) with 95% confidence intervals (CI) were recorded for continuous data. Randomized-effect model or fixed-effect model was applied according to the heterogeneity test.. Fifteen citations recruiting 456 patients associated with ES were eventually pooled, which involved 4 RCTs, 6 prospective studies, and 5 retrospective studies. Within the first year, it indicated PAH-SDT significantly ameliorated exercise capacity in 6-minute walk distance (6MWD) (I = 60.5%; WMD: 53.86 m, 95% CI [36.59, 71.13], P < .001), functional class (FC) (WMD = -0.71, 95% CI [-0.98, -0.44], P < .001) and Borg dyspnea index (WMD = -1.28, 95% CI [-1.86, -0.70], P < .001), in addition to hemodynamics, especially mean pulmonary arterial pressure by 5.70 mmHg (WMD = -5.70 mmHg, 95% CI [-8.19, -3.22], P < .001) and pulmonary vascular resistance by 4.20 wood U (WMD: -4.20, 95% CI [-7.32, -1.09], P = .008), but unsatisfactory effects in oxygen saturation at exercise (P = .747). In a prolonged medication, bosentan, a dual ERA, has been proved acting an important role in improving exercise tolerance of patients with ES (6MWD: I = 47.5%; WMD: 88.68 m, 95% CI [54.05, 123.3], P < .001; FC: I = 0.0%; WMD = -0.65, 95% CI [-1.10, -0.19], P = .006). While a nonsignificant change of 6MWD was noted in a long-term therapy of ambrisentan (P = .385). There existed rare evidence about the efficacy and safety of macitentan, phosphodiesterase-5 inhibitors (PDE5i), and prostanoids in a prolonged medication. Most AEs were recorded as mild to moderate with PAH-SDT, but about 4.3% individuals treated with endothelin receptor antagonists (ERAs) suffered from serious ones, and 3.9% suffered from death.. This systematic review and meta-analysis proved PAH-SDT as a safe and effective role in ES in an early stage. However, in a long-term treatment, bosentan has been supported for a lasting effect on exercise tolerance. A further multicenter research with a large sample about pharmacotherapy of ES is necessary.

Topics: Antihypertensive Agents; Bosentan; Eisenmenger Complex; Endothelin Receptor Antagonists; Exercise Tolerance; Hemodynamics; Humans; Hypertension, Pulmonary; Oxygen; Phenylpropionates; Phosphodiesterase 5 Inhibitors; Prostaglandins; Pyridazines; Pyrimidines; Sulfonamides

The endothelin peptides bind to two receptors found on cells of vasculature and in tissues. While the endothelin-A (ETA)-receptor is predominantly expressed in vascular smooth muscle cells, the endothelin-B (ETB)-receptor is also found in endothelial cells, fibroblasts, and neuronal cells. Activation of the endothelin system plays a driving role in several chronic cardiovascular diseases and several endothelin receptor antagonists (ERAs) (bosentan (6), ambrisentan (83) and macitentan (43)) have successfully been introduced as oral treatments for the life threatening condition of pulmonary arterial hypertension (PAH). This digest highlights the medicinal chemistry of the pyrimidine based ERAs 6 and 43 and describes the story that started with bosentan and culminated in macitentan (43). A condensed overview of the competitive landscape in the field of ERAs puts the different strategies and tactics applied by the medicinal chemists involved in this endeavor into perspective.

Topics: Bosentan; Chemistry, Pharmaceutical; Dose-Response Relationship, Drug; Humans; Molecular Structure; Pyrimidines; Receptors, Endothelin; Structure-Activity Relationship; Sulfonamides

Idiopathic pulmonary fibrosis (IPF) is a form of chronic progressive fibrosing interstitial lung disease of unknown origin. Recently, nintedanib and pirfenidone demonstrated efficacy in slowing disease progression and were approved by the US Food and Drug Administration. Although numerous treatments have been evaluated in IPF, none have shown significant decreases in mortality. The objective of this study was to identify all pharmacologic treatments evaluated for IPF and analyze their efficacy via Bayesian network meta-analysis and pairwise indirect treatment comparisons. This review did not evaluate the effect of steroid therapy.. We searched MEDLINE, Embase, and the Cochrane Library for studies published on or before August 2014. Studies were required to contain a randomized evaluation of nonsteroidal drug therapy for treatment of IPF and be published in English. Key outcomes of interest for this analysis were pulmonary function as measured by FVC as well as all-cause and respiratory-specific death. All outcomes were analyzed via a Bayesian framework.. Our review identified 30 eligible studies that evaluated 16 unique treatments. Under both the fixed-effect and random-effect models for respiratory-specific mortality, no treatments performed better than placebo. For all-cause mortality, pirfenidone and nintedanib had effects approaching significance with credible intervals slightly crossing the null under a fixed-effect model. Notably, for respiratory-specific mortality, all-cause mortality, and decline in percent predicted FVC, nintedanib and pirfenidone were virtually indistinguishable and no clear advantage was detected.. Although two treatments have been approved for IPF on the basis of reduced decline in pulmonary function, neither one has a clear advantage on mortality outcomes.

Topics: Acetylcysteine; Anti-Inflammatory Agents, Non-Steroidal; Anticoagulants; Azathioprine; Bayes Theorem; Bosentan; Endothelin Receptor Antagonists; Enzyme Inhibitors; Etanercept; Free Radical Scavengers; Humans; Idiopathic Pulmonary Fibrosis; Imatinib Mesylate; Immunosuppressive Agents; Indoles; Interferon-gamma; Phenylpropionates; Pyridazines; Pyridones; Pyrimidines; Recombinant Proteins; Sulfonamides; Vital Capacity; Warfarin

Pulmonary arterial hypertension (PAH) was previously considered a uniformly fatal disease, with patients succumbing to right heart failure and death at an average of 3 years after diagnosis. The past 20 years, however, have seen the development of numerous targeted therapies that have changed the natural history of PAH. As more pharmacologic agents have been approved and utilized, further advances in the design of and endpoints for clinical trials. This study will review some of these notable developments.. The successful design and completion of long-term, event-driven trials is exemplified in three recent studies: SERAPHIN, GRIPHON, and AMBITION. SERAPHIN and GRIPHON evaluated the newer agents, macitentan, an endothelin receptor antagonist, and selexipag, a prostacyclin receptor agonist, respectively. Both trials were large-scale studies that, in addition to showing marked effect on the primary endpoint of morbidity/mortality, clearly demonstrated that assessment of long-term effects of PAH therapies is feasible for new compounds. The AMBITION study evaluated a treatment strategy, namely up-front combination therapy with tadalafil and ambrisentan compared with monotherapy and showed the combination approach to be superior at decreasing the likelihood of clinical failure.. The evolution of clinical trials in PAH has direct implications for care of these patients. The short and long-term benefits of combination regimens suggest that the multidrug approach to PAH should, in fact, be standard of care for this disease.

Topics: Acetamides; Antihypertensive Agents; Clinical Trials as Topic; Endothelin Receptor Antagonists; Humans; Hypertension, Pulmonary; Inositol 1,4,5-Trisphosphate Receptors; Phenylpropionates; Phosphodiesterase 5 Inhibitors; Pyrazines; Pyridazines; Pyrimidines; Randomized Controlled Trials as Topic; Sulfonamides

Pulmonary arterial hypertension (PAH) is a chronic disorder of the pulmonary vasculature characterized by elevated mean pulmonary arterial pressure eventually leading to right-sided heart failure and premature death. Macitentan is an oral, once-daily, dual endothelin (ET)A and ETB receptor antagonist with high affinity and sustained receptor binding that was approved in the USA, Europe, Canada, and Switzerland for the treatment of PAH.. This review discusses the pharmacokinetics (PK) and pharmacodynamics (PD) of macitentan and its drug interaction potential based on preclinical and clinical data.. Up to date, macitentan is the only registered treatment for PAH that significantly reduced morbidity and mortality as a combined endpoint in a long-term event-driven study. The safety profile of macitentan is favorable with respect to hepatic safety and edema/fluid retention and may be better than that of other ET receptor antagonists such as bosentan and ambrisentan. The PK profile supports a once-a-day dosing regimen. Macitentan has limited interactions with other drugs. Based on these characteristics macitentan is an important new addition to the treatment of PAH.

Topics: Animals; Bosentan; Drug Interactions; Endothelin A Receptor Antagonists; Endothelin B Receptor Antagonists; Humans; Hypertension, Pulmonary; Phenylpropionates; Pyridazines; Pyrimidines; Sulfonamides

Pulmonary arterial hypertension (PAH) is a condition that leads to progressive right heart failure and death unless recognized and treated early. Endothelin, a potent endogenous vasoconstrictor, has been identified as an important mediator of PAH. Endothelin receptor antagonists (ERAs) have been associated with an improvement in exercise capacity and time to clinical worsening in patients with Group 1 PAH, and three different ERAs are currently approved for use in this population: bosentan, ambrisentan, and macitentan. While all three ERAs are generally well-tolerated, they each have important adverse effects that need to be recognized and monitored. In particular, they may cause anemia, peripheral edema, and mild cardiac, respiratory, neurologic, and gastrointestinal adverse effects to varying degrees. Although bosentan increases a patient's risk of developing liver transaminitis, ambrisentan and macitentan do not appear to confer the same risk of hepatotoxicity at this time. Important drug-drug interactions, particularly involving other drugs metabolized via the cytochrome P450 pathway, are important to recognize when prescribing ERAs. In this review, we provide a brief overview of the current state of knowledge as it relates to the adverse effect profiles, tolerability, and drug-drug interactions of this class of medication as informed by the results of randomized clinical trials, drug surveillance programs, and regulatory agencies.

Topics: Animals; Antihypertensive Agents; Bosentan; Chemical and Drug Induced Liver Injury; Drug Interactions; Drug Monitoring; Endothelin Receptor Antagonists; Heart Failure; Humans; Hypertension, Pulmonary; Phenylpropionates; Pyridazines; Pyrimidines; Risk; Sulfonamides

Topics: Administration, Oral; Adult; Antihypertensive Agents; Bosentan; Carbolines; Endothelin Receptor Antagonists; Epoprostenol; Female; Humans; Hypertension, Pulmonary; Infusions, Intravenous; Male; Phenylpropionates; Phosphodiesterase 5 Inhibitors; Piperazines; Pulmonary Artery; Purines; Pyridazines; Pyrimidines; Randomized Controlled Trials as Topic; Sildenafil Citrate; Sulfonamides; Sulfones; Tadalafil; Vascular Resistance; Vasodilator Agents

Since the discovery of endothelin (ET)-1 in 1988, the main components of the signalling pathway have become established, comprising three structurally similar endogenous 21-amino acid peptides, ET-1, ET-2 and ET-3, that activate two GPCRs, ETA and ETB . Our aim in this review is to highlight the recent progress in ET research. The ET-like domain peptide, corresponding to prepro-ET-193-166 , has been proposed to be co-synthesized and released with ET-1, to modulate the actions of the peptide. ET-1 remains the most potent vasoconstrictor in the human cardiovascular system with a particularly long-lasting action. To date, the major therapeutic strategy to block the unwanted actions of ET in disease, principally in pulmonary arterial hypertension, has been to use antagonists that are selective for the ETA receptor (ambrisentan) or that block both receptor subtypes (bosentan). Macitentan represents the next generation of antagonists, being more potent than bosentan, with longer receptor occupancy and it is converted to an active metabolite; properties contributing to greater pharmacodynamic and pharmacokinetic efficacy. A second strategy is now being more widely tested in clinical trials and uses combined inhibitors of ET-converting enzyme and neutral endopeptidase such as SLV306 (daglutril). A third strategy based on activating the ETB receptor, has led to the renaissance of the modified peptide agonist IRL1620 as a clinical candidate in delivering anti-tumour drugs and as a pharmacological tool to investigate experimental pathophysiological conditions. Finally, we discuss biased signalling, epigenetic regulation and targeting with monoclonal antibodies as prospective new areas for ET research.

Topics: Antineoplastic Agents; Aspartic Acid Endopeptidases; Benzazepines; Bosentan; Endothelin A Receptor Antagonists; Endothelin-1; Endothelin-2; Endothelin-3; Endothelin-Converting Enzymes; Endothelins; Epigenesis, Genetic; Humans; Hypertension, Pulmonary; Metalloendopeptidases; Neoplasms; Peptide Fragments; Phenylpropionates; Pyridazines; Pyrimidines; Receptor, Endothelin B; Sulfonamides; Vasodilator Agents

Use of endothelin receptor antagonists (ERAs) and riociguat, approved for treatment of pulmonary hypertension (PH), is contraindicated during pregnancy due to reported teratogenicity in animals. We aimed to investigate prescribing of these drugs in girls/women of childbearing age and to explore - as a secondary aim - the occurrence of pregnancies exposed to these drugs. Using the German Pharmacoepidemiological Research Database (GePaRD, claims data from 20% of the German population) we conducted cross-sectional analyses to determine prescribing prevalence of ERAs and riociguat between 2004 and 2019 and to characterize users and prescribing patterns. In a cohort analysis, we assessed the occurrence of pregnancies exposed to these drugs in the critical time window. Overall, we identified 407 women with ≥ 1 dispensation of bosentan between 2004 and 2019; the respective number was 73 for ambrisentan, 182 for macitentan, 31 for sitaxentan, and 63 for riociguat. In nearly all years, more than 50% of the girls/women were ≤ 40 years. Age-standardized prevalence was highest for bosentan (0.04/1000) in 2012 and 2013, followed by macitentan (0.03/1000) in 2018 and 2019. We observed 10 exposed pregnancies: 5 to bosentan, 3 to ambrisentan, and 2 to macitentan. The increased prevalence of macitentan and riociguat from 2014 onwards might reflect changes in PH treatment. Even though PH is a rare disease and pregnancy should be avoided in women with PH, particularly if they use ERAs, we identified pregnancies exposed to ERAs. Multi-database studies will be needed to assess the risk of these drugs on the unborn child.

Topics: Animals; Bosentan; Cross-Sectional Studies; Endothelin Receptor Antagonists; Female; Hypertension, Pulmonary

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.. 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.. 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.

Topics: Bosentan; Counseling; Cytochrome P-450 CYP2C8; Cytochrome P-450 CYP2C9; Endothelin Receptor Antagonists; Familial Primary Pulmonary Hypertension; Female; Humans; Hypertension, Pulmonary; Middle Aged; Pulmonary Arterial Hypertension; Receptors, Epoprostenol; Transaminases

Topics: Antihypertensive Agents; Chromatography, High Pressure Liquid; Humans; Isoxazoles; Linear Models; Phenylpropionates; Pyridazines; Pyrimidines; Reproducibility of Results; Sensitivity and Specificity; Sulfonamides; Tandem Mass Spectrometry; Thiophenes

Topics: Bosentan; Humans; Hypertension, Pulmonary; Idiopathic Pulmonary Fibrosis; Insurance Coverage; Japan; Phenylpropionates; Prevalence; Prognosis; Pulmonary Disease, Chronic Obstructive; Pyrazoles; Pyridazines; Pyrimidines; Sildenafil Citrate; Sulfonamides; Treatment Outcome; Universal Health Insurance

Therapeutic strategies for pulmonary arterial hypertension (PAH) have made remarkable progress over the last two decades. Currently, 3 types of drugs can be used to treat PAH; prostacyclins, phosphodiesterase 5 inhibitors, and endothelin receptor antagonists (ERA). In Japan, the first generation ERA bosentan was reimbursed in 2005, following which the 2nd generation ERAs ambrisentan and macitentan were reimbursed in 2009 and 2015, respectively. The efficacy of each ERA on hemodynamics in PAH patients remains to be elucidated. The aims of this study were to evaluate the hemodynamic effects of ERAs and compare these effects among each generation of ERAs.We retrospectively examined the clinical parameters of 42 PAH patients who were prescribed an ERA (15 bosentan, 12 ambrisentan, and 15 macitentan) and who underwent a hemodynamic examination before and after ERA introduction at our institution from January 2007 to July 2019.In a total of 42 patients, mean pulmonary arterial pressure (mPAP) and pulmonary vascular resistance (PVR) were significantly decreased and cardiac index was significantly increased after ERA introduction (P < 0.001) and the World Health Organization-Functional class (WHO-Fc) was significantly improved after ERA introduction (P = 0.005). Next, in a comparison between 1st and 2nd generation ERAs, 2nd generation ERAs were found to have brought about greater improvements in hemodynamic parameters (mPAP and PVR. P < 0.01), heart rate, brain natriuretic peptide, arterial oxygen saturation, and mixed venous oxygen saturation than the 1st generation ERA bosentan.We conclude that all ERAs could successfully improve the hemodynamics of PAH patients and that the newer generation ERAs, ambrisentan and macitentan, seemed to be preferable to bosentan.

Topics: Administration, Oral; Adult; Aged; Bosentan; Case-Control Studies; Endothelin Receptor Antagonists; Female; Hemodynamics; Humans; Japan; Male; Middle Aged; Phenylpropionates; Phosphodiesterase 5 Inhibitors; Placebos; Prostaglandins I; Pulmonary Arterial Hypertension; Pulmonary Wedge Pressure; Pyridazines; Pyrimidines; Retrospective Studies; Sulfonamides; Treatment Outcome; Vascular Resistance

Idiopathic pulmonary fibrosis (IPF) is a severe and often fatal disease with a median survival of 2 - 4 years after diagnosis. Since the publication of the German IPF guideline in 2013 new treatment trials have been published, necessitating an update of the pharmacological therapy of IPF. Different from the previous guideline, the GRADE system was discarded and replaced by the Oxford evidence classification system which allows a more differentiated judgement. The following pharmacological therapies were rated not suitable for the treatment of IPF patients (recommendation A; evidence 1-b): triple therapy with prednisolone, azathioprine and acetyl-cysteine; imatinib; ambrisentan; bosentan; macitentan. A less clear but still negative recommendation (B, 1-b) was attributed to the treatment of IPF with the phosphodiesterase-5-inhibitor sildenafil and acetyl-cysteine monotherapy. In contrast to the international guideline antacid therapy as a general treatment for IPF was rated negative, based on conflicting results of recent analyses (recommendation C; evidence 4). An unanimous positive recommendation was granted for the antifibrotic drugs nintedanib and pirfenidone for the treatment of IPF (A, 1-a). For some open questions in the management of IPF patients for which firm evidence is lacking the guideline also offers recommendations based on expert consensus.. Die idiopathische Lungenfibrose (idiopathische pulmonale Fibrose, IPF) ist eine schwerwiegende Lungenerkrankung, die häufig innerhalb von zwei bis vier Jahren nach Diagnosestellung zum Tod führt. Seit Veröffentlichung der deutschen IPF-Leitlinie im Jahr 2013 liegen neue Therapiestudien vor, die eine Neubewertung der Behandlungsstrategien erfordern. Abweichend von der Vorgängerleitlinie wurde in der aktuellen Überarbeitung nicht mehr das GRADE-System sondern die Oxford Evidenzsystematik mit drei Empfehlungsgraden (A, B, C) verwendet, weil dieses System eine differenziertere Betrachtung erlaubt. Folgende Medikamente wurden mit dem Empfehlungsgrad A und dem Evidenzgrad 1-b als nicht geeignet für die Behandlung der IPF klassifiziert: Triple-Therapie aus Prednisolon, Azathioprin und Acetylcystein; Antikoagulation mit Vitamin-K-Antagonisten; Imatinib; Ambrisentan; Bosentan; Macitentan. Weniger eindeutig ist die negative Bewertung des Phosphodiesterase-5-Inhibitors Sildenafil und der Acetylcystein-Monotherapie (Empfehlungsgrad B, Evidenzgrad 2-b). Eindeutig positiv fiel die Empfehlung für Nintedanib und Pirfenidon zur Behandlung von IPF-Patienten aus (Empfehlungsgrad A, Evidenzgrad 1-a). Mit Empfehlungsgrad C und Evidenzgrad 4 wurde der generelle Einsatz von Antazida zur Behandlung der IPF als nicht zu empfehlen bewertet, da die Datenlage widersprüchlich ist; hier weicht die deutsche Leitlinie auch am deutlichsten von der internationalen Leitlinie ab. Am Ende der Leitlinie wird aus Expertensicht zu offenen Fragen in der Therapie der IPF Stellung genommen, für die bisher keine ausreichende Evidenzbasis existiert.

Topics: Acetylcysteine; Adult; Aged; Aged, 80 and over; Antacids; Bosentan; Clinical Trials as Topic; Evidence-Based Medicine; Female; Gastroesophageal Reflux; Guideline Adherence; Humans; Idiopathic Pulmonary Fibrosis; Imatinib Mesylate; Indoles; Male; Middle Aged; Phenylpropionates; Pyridazines; Pyridones; Pyrimidines; Sildenafil Citrate; Sulfonamides

Newer endothelin receptor antagonists (ERAs) used to treat patients with pulmonary arterial hypertension (PAH) are associated with fewer drug-drug interactions than bosentan and require less monitoring. This, combined with a pharmacokinetic basis for improved efficacy, means there may be a clinical rationale for changing therapies. However, this can be challenging and few data on its safety in patients with PAH are available.. At the Royal Free Hospital in London, UK, home-based medication transitioning has been standard practice since 2009 to avoid unnecessary hospital visits for patients, unless there is a clinical imperative. In this audit of standard practice we evaluated the consequences of adopting such a strategy when transitioning PAH patients between ERA therapies.. Using a Clinical Nurse Specialist-led, home-based transitioning strategy, 92 patients with PAH were transitioned from bosentan to macitentan or ambrisentan. Observational data were analysed retrospectively. The majority of patients were female with PAH associated with connective tissue disease and their ERA was changed in the hope of improving efficacy. The process was well tolerated with no adverse events associated with the process. Seventeen patients died during the study (macitentan, n = 5; ambrisentan, n = 12). None of the deaths was considered related to ERA treatment. The majority of patients remained clinically stable, based on WHO functional class and exercise capacity.. An established home-based transitioning strategy can be adopted safely for patients with PAH changing ERA therapies. Most patients remained stable and the therapy change was well tolerated.

Topics: Adult; Aged; Aged, 80 and over; Antihypertensive Agents; Bosentan; Endothelin Receptor Antagonists; Female; Humans; Hypertension, Pulmonary; Male; Middle Aged; Phenylpropionates; Pyridazines; Pyrimidines; Retrospective Studies; Sulfonamides; Treatment Outcome

Topics: Administration, Oral; Age Factors; Bosentan; Drug Therapy, Combination; Endothelin Receptor Antagonists; Female; Humans; Hypertension, Pulmonary; Male; Middle Aged; Phenylpropionates; Phosphodiesterase 5 Inhibitors; Pyridazines; Pyrimidines; Retrospective Studies; Sildenafil Citrate; Sulfonamides; Tadalafil

Combination therapy with the phosphodiesterase type 5 inhibitors (PDE-5i) sildenafil or tadalafil and the endothelin receptor antagonists (ERA) bosentan, ambrisentan, or macitentan may cause mutual pharmacokinetic interactions in patients with pulmonary arterial hypertension (PAH).. The objective of this study was to analyze plasma drug concentrations in PAH patients receiving different combination treatments.. PAH patients receiving a stable combination treatment with ERA and PDE-5i with targeted dosage for at least 1 month were routinely assessed, including clinical parameters and plasma drug concentrations. Concentrations were normalized considering dose and time from last medication intake and presented as multiples of the expected mean (MoM) of the respective monotherapies.. A total of 125 PAH patients (84 female, 41 male, 57% idiopathic/heritable) were included. Sildenafil and tadalafil concentrations were lowest in combination with bosentan (MoM 0.44 ± 0.42, 95% confidence interval [CI] 0.30-0.57, and MoM 0.89 ± 0.53, 95% CI 0.50-1.28, respectively) compared to the combination with ambrisentan (MoM 1.3 ± 0.97, 95% CI 0.86-1.73, and MoM 1.67 ± 0.63, 95% CI 1.40-1.94, respectively) and macitentan (MoM 1.16 ± 0.87, 95% CI 0.86-1.46, and MoM 1.59 ± 0.99, 95% CI 0.80-2.38, respectively). The combination of sildenafil and bosentan led to more than twice the expected bosentan concentrations in 53.8%. Patients switching from sildenafil-bosentan to macitentan showed a significant increase in sildenafil concentrations (p < 0.001).. Only the combination with macitentan or ambrisentan led to targeted mean PDE-5i plasma concentrations and should therefore be preferred to combination with bosentan. Sildenafil-bosentan showed the strongest interaction, with low sildenafil and high bosentan concentrations. The study was not powered to analyze whether lower PDE-5i concentrations cause unsatisfying clinical response. However, plasma concentrations within a targeted range are desirable and may become of increasing importance.

Topics: Adult; Aged; Bosentan; Case-Control Studies; Drug Interactions; Drug Therapy, Combination; Endothelin Receptor Antagonists; Female; Humans; Hypertension, Pulmonary; Male; Middle Aged; Phenylpropionates; Phosphodiesterase 5 Inhibitors; Pyridazines; Pyrimidines; Sildenafil Citrate; Sulfonamides; Tadalafil

Endothelin receptor antagonists are approved for pulmonary arterial hypertension. Development of selective ET. Human isolated pulmonary (i.d. 5.5mm) and human radial (i.d. 3.23mm) artery ring segments were mounted in organ baths for isometric force measurement. Single concentration-contraction curves to endothelin-1 were constructed in the absence or presence of bosentan (1-10µM), macitentan (0.03-0.3µM) or ambrisentan (0.1-1µM).. All 3 endothelin antagonists caused competitive rightward shifts in the endothelin-1 concentration-response curves in both arteries. The Clark plot and analysis gave the following pK. Noting the maximum plasma levels attained from recommended oral doses of each antagonist in volunteers, the pK

Topics: Bosentan; Dose-Response Relationship, Drug; Endothelin Receptor Antagonists; Endothelin-1; Humans; Hypertension, Pulmonary; Phenylpropionates; Pulmonary Artery; Pyridazines; Pyrimidines; Radial Artery; Receptor, Endothelin A; Sulfonamides; Tissue Survival; Vasoconstriction

Inhibition of the transporter-mediated hepatobiliary elimination of bile salts is a putative mechanism for liver toxicity observed with some endothelin receptor antagonists (ERAs).. Sandwich-cultured human hepatocytes were used to study the hepatobiliary distribution and accumulation of exogenous taurocholate, ERAs and endogenous bile acids. The molecular mechanisms for findings in hepatocytes or clinical observations were further explored using either vesicular assays (efflux transporters) or transfected cell-lines (uptake transporters). Inhibition constants (IC50) were measured for the human hepatobiliary transporters bile salt export pump (BSEP), sodium taurocholate cotransporting polypeptide (NTCP), multidrug resistance protein 2 (MRP2), P-glycoprotein (Pgp), breast cancer resistance protein (BCRP), organic anion-transporting polypeptide 1B1 (OATP1B1) and OATP1B3.. The ERAs showed dose-dependent reductions in exogenous taurocholate cellular accumulation in human hepatocytes, with macitentan having the greatest effect. Consistent with their effects on bile acids, the ERAs inhibited bile transporters. IC50 values for OATP1B1 and OATP1B3 ranged from 2 µM for macitentan to 47 µM for ambrisentan. Macitentan and bosentan also inhibited NTCP with IC50 values of 10 and 36 µM, respectively. Similar to previously reported findings with sitaxsentan, BSEP inhibition was observed for bosentan and macitentan with IC50 values of 42 and 12 µM, respectively. In contrast, ambrisentan showed little or no inhibition of these transporters. Other transporters tested were weakly inhibited by the ERAs. Accumulation in hepatocytes was also a factor in the effects on bile transport. Macitentan demonstrated the greatest accumulation in human hepatocytes (∼100x) followed by sitaxsentan (∼40x), bosentan (∼20x) and ambrisentan (∼2x).. Significant differences in the inhibition of hepatic transporters were observed between the evaluated ERAs in vitro. Macitentan had the highest level of cellular accumulation and caused the greatest effects on bile acid distribution in human hepatocytes followed by sitaxsentan and bosentan. Ambrisentan showed a low potential to affect bile acids.

Topics: Adult; ATP Binding Cassette Transporter, Subfamily B, Member 1; ATP Binding Cassette Transporter, Subfamily G, Member 2; ATP-Binding Cassette Transporters; Bile; Bile Acids and Salts; Bosentan; Endothelin Receptor Antagonists; Female; Hepatocytes; Humans; Isoxazoles; Liver; Liver-Specific Organic Anion Transporter 1; Male; Membrane Transport Proteins; Middle Aged; Multidrug Resistance-Associated Proteins; Neoplasm Proteins; Organic Anion Transporters; Organic Anion Transporters, Sodium-Dependent; Organic Anion Transporters, Sodium-Independent; Phenylpropionates; Pyridazines; Pyrimidines; Receptors, Endothelin; Solute Carrier Organic Anion Transporter Family Member 1B3; Sulfonamides; Symporters; Taurocholic Acid; Thiophenes

Idiopathic pulmonary arterial hypertension (IPAH), formerly called primary pulmonary hypertension, is a rare disease (incidence and prevalence rates of approximately one and six cases per million inhabitants, respectively) with different clinical phenotypes. A group of diverse conditions manifest pulmonary arterial hypertension (PAH) and share similar pathological and/or clinical findings with IPAH. By definition, IPAH is diagnosed only after alternative diagnoses have been ruled out. Extensive investigation is needed to determine if PAH is associated with thyroid diseases, infectious diseases, autoimmune conditions, exposure to certain drugs (particularly anorexigens), certain genetic mutations, and so on. The presence of genetic abnormalities and risk factors (such as specific drug exposures) reinforces the "multiple hit" concept for the development of pulmonary hypertension. Fortunately, within the past two decades, therapeutic options have become available for IPAH, resulting in improved survival and clinical outcomes. At least seven different compounds have been registered for PAH treatment. However, even with aggressive PAH-specific therapy, mortality rates remain high (∼40% at 5 years). Given the high mortality rates, the use of combinations of agents that work by different pathways has been advocated (either as "add-on" therapy or initial "up front" therapy). Further, new therapeutic agents and treatment strategies are on the near horizon, aiming to further improve survival from the remarkable progress already seen.

Topics: Aminorex; Antihypertensive Agents; Appetite Depressants; Bosentan; Dasatinib; Epoprostenol; Familial Primary Pulmonary Hypertension; Fenfluramine; Genetic Predisposition to Disease; Humans; Hypertension, Pulmonary; Iloprost; Phenylpropionates; Piperazines; Protein Kinase Inhibitors; Purines; Pyrazoles; Pyridazines; Pyrimidines; Risk Factors; Sildenafil Citrate; Sulfonamides; Sulfones; Thiazoles; Vasodilator Agents

Two endothelin receptor antagonists (ERAs), bosentan and ambrisentan, are currently approved for the treatment of pulmonary arterial hypertension (PAH), a devastating disease involving an activated endothelin system and aberrant contraction and proliferation of pulmonary arterial smooth muscle cells (PASMC). The novel ERA macitentan has recently concluded testing in a Phase III morbidity/mortality clinical trial in PAH patients. Since the association and dissociation rates of G protein-coupled receptor antagonists can influence their pharmacological activity in vivo, we used human PASMC to characterize inhibitory potency and receptor inhibition kinetics of macitentan, ambrisentan and bosentan using calcium release and inositol-1-phosphate (IP(1)) assays. In calcium release assays macitentan, ambrisentan and bosentan were highly potent ERAs with K(b) values of 0.14 nM, 0.12 nM and 1.1 nM, respectively. Macitentan, but not ambrisentan and bosentan, displayed slow apparent receptor association kinetics as evidenced by increased antagonistic potency upon prolongation of antagonist pre-incubation times. In compound washout experiments, macitentan displayed a significantly lower receptor dissociation rate and longer receptor occupancy half-life (ROt(1/2)) compared to bosentan and ambrisentan (ROt(1/2):17 minutes versus 70 seconds and 40 seconds, respectively). Because of its lower dissociation rate macitentan behaved as an insurmountable antagonist in calcium release and IP(1) assays, and unlike bosentan and ambrisentan it blocked endothelin receptor activation across a wide range of endothelin-1 (ET-1) concentrations. However, prolongation of the ET-1 stimulation time beyond ROt(1/2) rendered macitentan a surmountable antagonist, revealing its competitive binding mode. Bosentan and ambrisentan behaved as surmountable antagonists irrespective of the assay duration and they lacked inhibitory activity at high ET-1 concentrations. Thus, macitentan is a competitive ERA with significantly slower receptor dissociation kinetics than the currently approved ERAs. Slow dissociation caused insurmountable antagonism in functional PASMC-based assays and this could contribute to an enhanced pharmacological activity of macitentan in ET-1-dependent pathologies.

Topics: Animals; Bosentan; Calcium; CHO Cells; Clinical Trials, Phase III as Topic; Cricetinae; Endothelin Receptor Antagonists; Endothelin-1; Familial Primary Pulmonary Hypertension; Humans; Hypertension, Pulmonary; Inositol Phosphates; Myocytes, Smooth Muscle; Phenylpropionates; Pulmonary Artery; Pyridazines; Pyrimidines; Receptors, Endothelin; Sulfonamides