Pharmacokinetics of the novel oral prostacyclin receptor agonist selexipag in subjects with hepatic or renal impairment

A real-world analysis of safety profile of selexipag by using FDA adverse Event Reporting System (FAERS)

BACKGROUND

The current investigation sought to conduct a real-world analysis of adverse events (AEs) associated with selexipag by utilizing data from the Food and Drug Administration Adverse Event Reporting System (FAERS).

METHODS

The Reporting Odds Ratios (ROR) and the Medicines Healthcare Products Regulatory Agency (MHRA) method were employed to assess the potential associations between selexipag and AEs. Case reports of adverse drug reaction (ADR) related to selexipag were systematically sourced from PubMed, Embase, and Web of Science databases.

RESULTS

Our analysis identified 281 Preferred Terms (PTs) signals across 20 System Organ Classes (SOCs) were found to meet the screening threshold. The most common AEs were consistent with instructions, randomized controlled trials (RCTs), and case reports. Of significant note, unexpected AEs principally target SOCs of infections and infestations, blood and lymphatic system, renal and urinary disorders, hepatobiliary disorders, including pneumonia, metapneumovirus, decreased hemoglobin. transfusion, iron-deficiency anemia, dialysis hypotension, abnormal creatinine renal clearance, liver function test increased, hepatic function abnormal, hepatic enzyme increased. Within the pediatric population, unexpected signals such as pyrexia, pneumonia, and intussusception necessitate special precautionary measures.

CONCLUSIONS

The findings contribute valuable insights to clinical practice, reinforcing the importance of vigilant monitoring, and can be instrumental in guiding both therapeutic applications and safety assessments of this particular medication.

Therapeutic approaches for pulmonary hypertension in patients with chronic kidney disease

PURPOSE OF REVIEW

Pulmonary hypertension is a common comorbidity in patients with chronic kidney disease (CKD), but therapeutic options are limited. We discuss the epidemiology of pulmonary hypertension in patients with CKD and review therapies for pulmonary hypertension with a focus on emerging treatments for pulmonary arterial hypertension (PAH).

RECENT FINDINGS

The definition of pulmonary hypertension has been updated to a lower threshold of mean pulmonary artery pressures of more than 20 mmHg, potentially leading to more patients with CKD to qualify for the diagnosis of pulmonary hypertension. Endothelin receptor antagonists, a class of medications, which demonstrated efficacy in patients with PAH, have been shown to slow progression of CKD, but their efficacy in lowering pulmonary artery pressures and their effects on reducing cardiovascular mortality in this population remains unproven. Sotatercept, a novel activin signaling inhibitor, which was previously studied in dialysis patients has been shown to increase exercise capacity in patients with PAH. These studies may lead to new specific therapies for pulmonary hypertension in patients with CKD.

SUMMARY

Pulmonary hypertension is common in patients with CKD. Although our understanding of factors leading to pulmonary hypertension in this population have evolved, evidence supporting disease-specific therapy in CKD is limited arguing for larger, long-term studies.

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.

Effect of quercetin on the pharmacokinetics of selexipag and its active metabolite in beagles

CONTEXT

As an inhibitor cytochrome P450 family 2 subfamily C polypeptide 8 (CYP2C8), quercetin is a naturally occurring flavonoid with its glycosides consumed at least 100 mg per day in food. However, it is still unknown whether quercetin and selexipag interact.

OBJECTIVE

The study investigated the effect of quercetin on the pharmacokinetics of selexipag and ACT-333679 in beagles.

MATERIALS AND METHODS

The ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was used to investigate the pharmacokinetics of orally administered selexipag (2 mg/kg) with and without quercetin (2 mg/kg/day for 7 days) pre-treatment in beagles. The effect of quercetin on the pharmacokinetics of selexipag and its potential mechanism was studied through the pharmacokinetic parameters.

RESULTS

The assay method was validated for selexipag and ACT-333679, and the lower limit of quantification for both was 1 ng/mL. The recovery and the matrix effect of selexipag were 84.5-91.58% and 94.98-99.67%, while for ACT-333679 were 81.21-93.90% and 93.17-99.23%. The UPLC-MS/MS method was sensitive, accurate and precise, and had been applied to the herb-drug interaction study of quercetin with selexipag and ACT-333679. Treatment with quercetin led to an increased in C_max and AUC_0-t of selexipag by about 43.08% and 26.92%, respectively. While the ACT-333679 was about 11.11% and 18.87%, respectively.

DISCUSSION AND CONCLUSION

The study indicated that quercetin could inhibit the metabolism of selexipag and ACT-333679 when co-administration. Therefore, the clinical dose of selexipag should be used with caution when co-administered with foods high in quercetin.

Liver abnormalities in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a cardiopulmonary disease with high mortality. In recent years, it has been recognized that PAH is a multi-organ system disease, involving the systemic circulation, kidneys, skeletal muscles, and the central nervous system, among others. Right heart failure produces congestive hepatopathy, a disease state that has direct consequences on liver biochemistry, histology, and systemic glucose and lipid metabolism. This article aims to summarize the consequences of congestive hepatopathy with an emphasis on liver biochemistry, histology, and PAH-targeted therapy. Furthermore, PAH-specific changes in glucose and lipid metabolism will be discussed.

Pharmacokinetics of daridorexant, a dual orexin receptor antagonist, are not affected by renal impairment

The aim of this study was to evaluate the impact of renal impairment on the pharmacokinetics (PKs), safety, and tolerability of daridorexant, a dual orexin receptor antagonist intended for the treatment of insomnia. A single‐center, open‐label study evaluated the PKs of daridorexant in patients with severe renal function impairment (SRFI; determined by creatinine clearance using the Cockcroft‐Gault equation; N = 8) not on dialysis, and in matched control subjects (based on sex, age, and body weight; N = 7). A single oral dose of daridorexant 25 mg was orally administered in the morning. Blood samples were collected up to 72 h postdose for PK assessments of daridorexant. In patients with SRFI, maximum plasma concentrations (C_max; geometric mean ratio [GMR] and 90% confidence interval [CI]: 0.94 [0.60–1.46]), time to reach C_max (T_max; median difference [90% CI] of −0.25 h [−0.75 to 0.25]), and half‐life (GMR [90% CI] of 0.99 [0.66–1.48]), were virtually unchanged. Exposure (area under the plasma concentration‐time profile) to daridorexant was slightly higher in patients with SRFI than in control subjects with the GMR (90% CI) being 1.16 (0.63–2.12). No safety issue of concern was detected as all adverse events were transient and of mild or moderate intensity, and no treatment‐related effects on vital signs, clinical laboratory, or electrocardiogram variables were observed following daridorexant administration in patients with SRFI and control subjects. Based on these observations, PK alterations of daridorexant due to renal function impairment are not considered of clinical relevance and no dose adjustment is necessary in these patients.

Selexipag for the treatment of pulmonary arterial hypertension

INTRODUCTION

: Pulmonary arterial hypertension (PAH) is a rare pulmonary vasculopathy. This review focuses on selexipag, a prostacyclin receptor agonist validated for the treatment of PAH.

AREAS COVERED

We review the structure, mechanisms of action, pharmacokinetics, and pharmacodynamics of selexipag. Clinical efficacy and tolerability are discussed using the main clinical trial published for selexipag (GRIPHON) and its post-hoc analysis.

EXPERT OPINION

Selexipag should be added as a triple oral combination therapy in case of insufficient response to oral combination therapy with endothelin receptor antagonist and phosphodiesterase 5 inhibitor. However, selexipag should not replace parenteral prostacyclin in high-risk patients.

Clinical evaluation of drug-drug interactions between the cytochrome P450 substrates selexipag and clopidogrel in Japanese volunteers

AIMS

The strong cytochrome P450 (CYP) 2C8 inhibitor gemfibrozil has been demonstrated to increase the area under the plasma concentration-time curve from 0 to infinity (AUC_0-∞ ) of ACT-333679, an active metabolite of selexipag, by 11-fold. Similarly to gemfibrozil, the CYP2C8 inhibitor clopidogrel increased ACT-333679 concentration by 1.9-fold after a single loading dose (300 mg once daily) and 2.7-fold after repeated treatment with the maintenance dose (75 mg once daily) in Europeans. However, the effects of clopidogrel on the pharmacokinetics of selexipag and ACT-333679 have not been fully elucidated in the Japanese population.

METHODS

We investigated the effect of clopidogrel on the pharmacokinetics of selexipag and ACT-333679 in 14 healthy Japanese volunteers.

RESULTS

The concomitant administration of clopidogrel with selexipag did not influence the maximum concentration and AUC_0-∞ of selexipag, whereas it significantly increased AUC_0-∞ of ACT-333679 by approximately 1.90-fold (90% confidence interval 1.69-2.14) without changing the maximum concentration. When selexipag was administered 1 day after clopidogrel was discontinued, the increase in AUC_0-∞ of ACT-333679 was 1.37-fold (90% confidence interval 0.93-2.02), suggesting that, although the inhibitory effect of clopidogrel on CYP2C8 was reduced, it persisted for at least 1 day after withdrawal.

CONCLUSION

Our results demonstrated the impact of clopidogrel on the pharmacokinetics of selexipag and its active metabolite and suggested that selexipag should be carefully prescribed with clopidogrel with dose adjustment or reducing the dosing frequency in Japanese clinical settings.

Clopidogrel, a CYP2C8 inhibitor, causes a clinically relevant increase in the systemic exposure to the active metabolite of selexipag in healthy subjects

Aims

Selexipag is a prostacyclin receptor agonist approved for the treatment of pulmonary arterial hypertension. Cytochrome P450 (CYP) 2C8 is involved in the metabolism of selexipag and its active metabolite, ACT‐333679. This study evaluated the interaction of selexipag and clopidogrel, a CYP2C8 inhibitor.

Methods

The study had a 2‐treatment, 1‐sequence, crossover design. Pharmacokinetics (PK) and CYP2C8 genotype were assessed in healthy male subjects administered selexipag (200 μg twice daily [b.i.d.]) alone or with clopidogrel (300 mg single dose or 75 mg once daily [o.d.]). PK modelling and simulation were conducted to support dosing recommendations.

Results

Clopidogrel had a comparatively small effect on selexipag (<1.5‐fold difference in any PK variable). For ACT‐333679, the major contributor to the drug effect, the area under the plasma concentration–time curve during a dose interval and the maximum plasma concentration increased 2.25‐fold (90% confidence interval [CI] 2.06, 2.46) and 1.69‐fold (90% CI 1.55, 1.84), respectively with clopidogrel 300 mg and 2.70‐fold (90% CI 2.45, 2.96) and 1.90‐fold (90% CI 1.72, 2.11), respectively with clopidogrel 75 mg. The effect of clopidogrel on selexipag and ACT‐333679 exposure was comparable for all identified CYP2C8 genotypes. PK simulations predicted comparable exposure to ACT‐333679 following selexipag 400 μg b.i.d., 400 μg o.d. in combination with clopidogrel 75 mg o.d and 200 μg b.i.d. with clopidogrel 75 mg o.d.

Conclusion

Results suggest that ACT‐333679 exposure can be maintained within the therapeutic range by reducing selexipag dosing frequency to o.d. or dose to half, when selexipag is coadministered with clopidogrel.

Selexipag in the management of pulmonary arterial hypertension: an update

Selexipag is a compound that was designed to overcome the issues associated with oral administration of prostanoid compounds, beraprost and treprostinil in the treatment of pulmonary hypertension (PAH). As a selective IP agonist, it was designed to avoid the off-target prostanoid effects especially in the gastrointestinal system. To place this compound in context, this paper briefly reviews the efficacy, tolerability, and safety of subcutaneous, inhaled, and oral prostanoid preparations and comparesthemto selexipag. Selexipag is the first agent targeting a prostanoid receptor where a reduction in the primary efficacy morbidity/mortality composite end-point has been demonstrated. While safety outcomes favor selexipag over placebo, tolerability issues remain. Efficacy in terms of improvement in effort tolerance, hemodynamic and mortality benefit is less than seen with IV therapy. This is the first prostanoid demonstrated in a clinical trial to have added benefit in those on background double combination therapy and the first non IV prostanoid to demonstrate outcome benefit in the connective tissue disease (CTD) population in a randomized controlled trial.

Contribution of Human Liver and Intestinal Carboxylesterases to the Hydrolysis of Selexipag In Vitro

In liver microsomes, selexipag (NS-304; ACT-293987) mainly undergoes hydrolytic removal of the sulfonamide moiety by carboxylesterase 1 (CES1) to yield the pharmacologically active metabolite MRE-269 (ACT-333679). However, it is not known how much CES in the liver and intestine contributes to the hydrolysis of selexipag or how selexipag is metabolized in the intestine, including by hydrolysis. To obtain a better understanding of selexipag metabolism in humans, we determined the percentage contribution of CES1 and carboxylesterase 2 (CES2) to the hydrolysis of selexipag and 7 of its analogs with different sulfonamide moieties and evaluated its nonhydrolytic metabolism in human liver microsomes and human intestinal microsomes (HIMS). For selexipag, the percentage contributions of CES1 and CES2 in human liver microsomes were 77.0% and 9.99%, respectively, while the percentage contribution of CES2 in HIMS was 100%. In HIMS, the rate of hydrolysis of selexipag was the lowest among the compounds tested, and no difference between the presence and absence of nicotinamide adenine dinucleotide phosphate was noted. We infer from these results that selexipag is likely to be hydrolyzed by CES2 as well as CES1, and only selexipag itself and the MRE-269 produced by hydrolysis in the intestine would be absorbed after oral administration.

Treatment of rat congenital diaphragmatic hernia with sildenafil and NS-304, selexipag's active compound, at the pseudoglandular stage improves lung vasculature

Patients with congenital diaphragmatic hernia (CDH) often suffer from severe pulmonary hypertension, and the choice of current vasodilator therapy is mostly based on trial and error. Because pulmonary vascular abnormalities are already present early during development, we performed a study to modulate these pulmonary vascular changes at an early stage during gestation. Pregnant Sprague-Dawley rats were treated with nitrofen at day 9.5 of gestation (E9.5) to induce CDH in the offspring, and subsequently, the phosphodiesterase-5 inhibitor sildenafil and/or the novel prostaglandin-I receptor agonist selexipag (active compound NS-304) were administered from E17.5 until E20.5. The clinical relevant start of the treatment corresponds to week 20 of gestation in humans, when CDH is usually detected by ultrasound. CDH pups showed increased density of air saccules that was reverted after the use of only sildenafil. The pulmonary vascular wall was thickened, and right ventricular hypertrophy was present in the CDH group and improved both after single treatment with sildenafil or selexipag, whereas the combination therapy with both compounds did not have additive value. In conclusion, antenatal treatment with sildenafil improved airway morphogenesis and pulmonary vascular development, whereas selexipag only acted positively on pulmonary vascular development. The combination of both compounds did not act synergistically, probably because of a decreased efficiency of both compounds caused by cytochrome- P450 3A4 interaction and induction. These new insights create important possibilities for future treatment of pulmonary vascular abnormalities in CDH patients already in the antenatal period of life.

Population Modeling of Selexipag Pharmacokinetics and Clinical Response Parameters in Patients With Pulmonary Arterial Hypertension

Selexipag (Uptravi) is an oral selective IP prostacyclin receptor agonist approved for the treatment of pulmonary arterial hypertension (PAH). The pivotal GRIPHON study was the largest clinical study ever conducted in PAH patients, providing long‐term data from 1,156 patients. PAH comedication did not affect exposure to selexipag, while exposure to its active metabolite ACT‐333679 was reduced by 30% when taken in combination, clinically not relevant in the context of individual dose up‐titration. Using log‐linear regression models linking model‐predicted steady‐state exposure to pharmacodynamics (PD), exposure to selexipag and ACT‐333679 showed some statistically significant, albeit not clinically relevant, effects on exercise capacity, laboratory values, and the occurrence of prostacyclin‐related adverse events, but not on vital signs or adverse events denoting hemorrhage. Using suitable modeling techniques, the GRIPHON study yielded clinically relevant data with limited burden of pharmacokinetics (PK) blood sampling, demonstrating that PK/PD modeling enables firm conclusions even with sparse PK and PD sampling.

Clinical pharmacology, efficacy, and safety of selexipag for the treatment of pulmonary arterial hypertension

INTRODUCTION

Selexipag is the first oral, non-prostanoid, selective prostacyclin receptor (IP receptor) agonist, approved for the long-term treatment of pulmonary arterial hypertension (PAH) in adult patients. Areas covered: This article reviews the clinical pharmacology, efficacy, and safety of selexipag in the treatment of PAH. Expert opinion: Selexipag is the first oral drug that selectively targets the prostacyclin pathway, and has evidence of long-term efficacy and safety. In the global phase 3 study GRIPHON (NCT01106014) in PAH patients, selexipag significantly reduced the risk of the primary composite outcome of morbidity/mortality (M/M). The adverse events in the selexipag group were consistent with the known side effects of prostacyclin, including headache, nausea, jaw pain, and diarrhea. Importantly, selexipag was efficacious and safe irrespective of whether or not patients were already receiving other PAH therapies. With selexipag approval, triple oral combination therapy addressing three important pathways is available for patients with PAH. Selexipag has one major metabolite, ACT-333679, which is also a selective IP receptor agonist, with 37-fold higher potency than selexipag. Pharmacokinetic properties of ACT-333679 permit twice-daily dosing of selexipag, providing a more convenient treatment compared to prostacyclin or its analogs. For patients with moderate hepatic impairment a once-daily regimen is recommended.

Selexipag: A Review in Pulmonary Arterial Hypertension

Selexipag (Uptravi^®) is an orally active, first-in-class, selective prostacyclin IP receptor agonist. Selexipag was approved recently in the EU for the long-term treatment of pulmonary arterial hypertension (PAH) in adult patients with WHO functional class (FC) II or III as combination therapy in patients insufficiently controlled with an endothelin receptor antagonist and/or a phosphodiesterase type 5 inhibitor or as monotherapy in patients who are not candidates for these therapies, and in the USA for the treatment of PAH (WHO Group I) to delay disease progression and reduce the risk of hospitalization for PAH. Selexipag (200-1600 μg twice daily, as tolerated) significantly reduced the risk of the primary composite endpoint of all-cause death or a complication related to PAH (whichever happened first) versus placebo in patients with PAH (mainly WHO FC II or III) in the large, randomized, placebo-controlled GRIPHON study. The treatment effect was largely driven by significant reductions in disease progression and hospitalization for PAH. However, selexipag did not significantly reduce all-cause mortality. Additionally, the observed treatment effect was consistent in a broad range of prespecified subgroups, including treatment-naïve patients and those patients who were already receiving PAH-specific treatment at baseline. Exercise capacity was also improved with selexipag versus placebo. Selexipag was generally well tolerated, with an adverse event profile consistent with other therapies targeting the prostacyclin pathway. Thus, selexipag extends the treatment options available in patients with PAH.

Selexipag, an Oral Prostacyclin-Receptor Agonist for Pulmonary Arterial Hypertension

OBJECTIVE

To evaluate the data supporting the approval of selexipag and discuss its potential place in therapy for managing pulmonary arterial hypertension (PAH).

DATA SOURCES

A systematic review of the literature for all relevant articles was performed through January 16, 2017, using MEDLINE and SCOPUS. A manual search of references from reports of clinical trials, review articles, and recent conference abstracts was performed to identify additional relevant studies.

STUDY SELECTION AND DATA EXTRACTION

Eligible citations included in vitro or in vivo evaluations of selexipag, with no restrictions on patient population or indication. Data related to the patient populations and outcomes of interest were extracted from each citation.

DATA SYNTHESIS

Single phase II and phase III trials have been published evaluating selexipag in patients with PAH. In 43 patients, the phase II trial showed that selexipag significantly reduced pulmonary vascular resistance by 30% versus placebo ( P = 0.0045) and improved 6-minute walk distance by 24 m ( P < 0.05). The larger phase III trial enrolled 1156 patients with PAH, showing that selexipag lowered the incidence of death or PAH-related complications by 40% versus placebo ( P < 0.001). Selexipag also improved 6-minute walk distance and lowered hospitalization risk. Common adverse events included headache, diarrhea, nausea, and jaw pain.

CONCLUSIONS

The specific role of selexipag for managing PAH patients is unclear because of its modest efficacy, lack of mortality reduction, and cost similar to intravenous prostacyclins. Additional clinical trials exploring combination therapy as well as its role in other types of pulmonary hypertension are needed.

Selexipag in Pulmonary Arterial Hypertension: Most Updated Evidence From Recent Preclinical and Clinical Studies

Pulmonary arterial hypertension (PAH) is a relatively rare disease that, due to its chronic nature, has always been difficult to treat effectively. Selexipag is an oral prostacyclin (PGI₂ ) agonist that was approved by US Food and Drug Administration (US FDA) in December 2015 for the treatment of PAH. After its success in phase 1 and phase 2 clinical trials regarding the convenient oral twice-daily dosing and low side-effect profile, selexipag raised the hope of controlling the disease progression in PAH patients. In the recently completed multicentered phase 3 study (GRIPHON), selexipag has been shown to reduce death and hospitalization due to PAH significantly, an effect that was consistent across different ranges of maintenance dose. In the same study selexipag use was also associated with an increase in 6-minute walk distance (a measure of symptom severity) from baseline, but no significant improvement in all-cause mortality could be observed. The results of the ongoing phase 3 studies (TRITON and TRANSIT-1) are expected to throw some more light on the safety and efficacy of this novel molecule across various treatment scenarios. Hence, our article aims to summarize all the available information from preclinical and clinical studies published to date on the pharmacodynamics, pharmacokinetics, efficacy, safety (in general and in scenarios such as hepatic and renal function impairment), significant drug interactions (with warfarin and antiretroviral drugs), and clinical significance of oral selexipag in patients with PAH.

Selexipag in the treatment of pulmonary arterial hypertension: design, development, and therapy

Pulmonary arterial hypertension is characterized by abnormalities in the small pulmonary arteries including increased vasoconstriction, vascular remodeling, proliferation of smooth muscle cells, and in situ thrombosis. Selexipag, a novel, oral prostacyclin receptor agonist, has been shown to improve hemodynamics in a phase II clinical trial and reduce clinical worsening in a large phase III clinical trial involving patients with pulmonary arterial hypertension. In this paper, we describe the prostacyclin signaling pathway, currently available oral prostanoid medications, and the development and clinical use of selexipag.

Pharmacokinetics of the novel oral prostacyclin receptor agonist selexipag in subjects with hepatic or renal impairment

AIM

The aim of the present study was to explore the effect of hepatic or renal dysfunction on the pharmacokinetics (PK), tolerability and safety of selexipag, an orally active prostacyclin receptor agonist.

METHODS

Two prospective, open-label studies evaluated the PK of selexipag and its active metabolite ACT-333679 in healthy subjects and in subjects with mild, moderate and severe hepatic impairment or severe renal function impairment (SRFI). A single dose of 200 μg or 400 μg was administered. The PK parameters were derived from plasma concentration-time profiles.

RESULTS

Exposure increased with the severity of hepatic impairment. Geometric mean ratios and 90% confidence intervals of the area under the concentration-time curve from time zero to infinity (AUC0-∞ ) for selexipag and ACT-333679 increased 2.1-fold (1.7-2.6) and 1.2-fold (0.9-1.6) in subjects with mild hepatic impairment, and 4.5-fold (3.4-5.8) and 2.2-fold (1.7-2.8) in subjects with moderate hepatic impairment when compared with healthy subjects. The two subjects with severe hepatic impairment showed similar dose-normalized exposure to that of subjects with moderate hepatic impairment. A 1.7-fold increase in the AUC0-∞ of selexipag and ACT-333679 was observed with SRFI compared with healthy subjects. Although exposure to selexipag and/or ACT-333679 was higher in subjects with mild or moderate hepatic impairment or SRFI vs. healthy subjects, no safety concerns were raised in these groups.

CONCLUSIONS

Based on these observations, the PK data suggest that the clinically used starting dose needs no adjustments in patients with mild or moderate hepatic impairment or SRFI. However, doses should be up-titrated with caution in these patients. The small number of subjects limits the interpretation of selexipag PK in subjects with severe hepatic impairment.