Aprocitentan and the endothelin system in resistant hypertension

Aprocitentan: First Approval

Aprocitentan (TRYVIO™) is a once-daily oral dual endothelin A (ETA) and B (ETB) receptor antagonist developed by Idorsia Pharmaceuticals for the treatment of hypertension. The endothelin pathway has been implicated in hypertension. Aprocitentan inhibits the binding of endothelin-1 to ETA and ETB receptors, thereby preventing its deleterious effects and lowering blood pressure. In March 2024, aprocitentan received its first approval in the USA for the treatment of hypertension in combination with other antihypertensive drugs, to lower blood pressure in adults who are not adequately controlled on other drugs. This article summarizes the milestones in the development of aprocitentan leading to this first approval for hypertension not adequately controlled on other drugs.

Population pharmacokinetics of the dual endothelin receptor antagonist aprocitentan in subjects with or without essential or resistant hypertension

Aprocitentan is a novel, potent, dual endothelin receptor antagonist that recently demonstrated efficacy in the treatment of difficult-to-treat (resistant) hypertension. The aim of this study was to develop a population pharmacokinetic (PK) model describing aprocitentan plasma concentration over time, to investigate relationships between subject-specific factors (covariates) and model parameters, and to quantify the influence of the identified covariates on the exposure to aprocitentan via model-based simulations, enabling judgment about the clinical relevance of the covariates.PK data from 902 subjects in ten Phase 1, one Phase 2, and one Phase 3 study were pooled to develop a joint population PK model. The concentration-time course of aprocitentan was described by a two-compartment model with absorption lag time, first-order absorption and elimination, and reduced relative bioavailability following very high doses of 300 and 600 mg.The population PK model described the observed data well. Volume and clearance parameters were associated with body weight. Renal function as reflected by estimated glomerular filtration rate (eGFR), hepatic impairment, and sex were identified as relevant covariates on clearance.The subject-specific characteristics of body weight, eGFR, hepatic impairment, and sex were shown to influence exposure parameters area under the concentration-time curve and maximum concentration in steady state to a limited extent, i.e., not more than 25% different from a reference subject, and therefore do not warrant dose adjustments.

Resistant Hypertension: Disease Burden and Emerging Treatment Options

PURPOSE OF REVIEW

To define resistant hypertension (RHT), review its pathophysiology and disease burden, identify barriers to effective hypertension management, and to highlight emerging treatment options.

RECENT FINDINGS

RHT is defined as uncontrolled blood pressure (BP) ≥ 130/80 mm Hg despite concurrent prescription of ≥ 3 or ≥ 4 antihypertensive drugs in different classes or controlled BP despite prescription of  ≥ to 4 drugs, at maximally tolerated doses, including a diuretic. BP is regulated by a complex interplay between the renin-angiotensin-aldosterone system, the sympathetic nervous system, the endothelin system, natriuretic peptides, the arterial vasculature, and the immune system; disruption of any of these can increase BP. RHT is disproportionately manifest in African Americans, older patients, and those with diabetes and/or chronic kidney disease (CKD). Amongst drug-treated hypertensives, only one-quarter have been treated intensively enough (prescribed > 2 drugs) to be considered for this diagnosis. New treatment strategies aimed at novel therapeutic targets include inhibition of sodium-glucose cotransporter 2, aminopeptidase A, aldosterone synthesis, phosphodiesterase 5, xanthine oxidase, and dopamine beta-hydroxylase, as well as soluble guanylate cyclase stimulation, nonsteroidal mineralocorticoid receptor antagonism, and dual endothelin receptor antagonism. The burden of RHT remains high. Better use of currently approved therapies and integrating emerging therapies are welcome additions to the therapeutic armamentarium for addressing needs in high-risk aTRH patients.

Taming resistant hypertension: The promise of novel pharmacologic approaches and renal denervation

Resistant hypertension is associated with an exceedingly high cardiovascular risk and there remains an unmet therapeutic need driven by pathophysiologic pathways unaddressed by guideline-recommended therapy. While spironolactone is widely considered as the preferable fourth-line drug, its broad application is limited by its side effect profile, especially off-target steroid receptor-mediated effects and hyperkalaemia in at-risk subpopulations. Recent landmark trials have reported promising safety and efficacy results for a number of novel compounds targeting relevant pathophysiologic pathways that remain unopposed by contemporary drugs. These include the dual endothelin receptor antagonist, aprocitentan, the aldosterone synthase inhibitor, baxdrostat and the nonsteroidal mineralocorticoid receptor antagonist finerenone. Furthermore, the evidence base for consideration of catheter-based renal denervation as a safe and effective adjunct therapeutic approach across the clinical spectrum of hypertension has been further substantiated. This review will summarise the recently published evidence on novel antihypertensive drugs and renal denervation in the context of resistant hypertension.

A Need for Improvement in the Definition of Resistant Arterial Hypertension

With the medical and social importance of resistant arterial hypertension (HTN) in mind, we had three goals in this paper: to study the definitions of resistant HTN in the guidelines on the topic, to analyze them, and to suggest some improvements. We found (at least) eleven insufficiencies in the definition of resistant HTN: (1) different blood pressure (BP) values are used for diagnoses; (2) the number of BP measurements is not specified; (3) the time-frame for the definition is not obtained; (4) it fails to provide normal or target or controlled BP values; (5) secondary HTN is not currently defined as true resistant HTN, but as apparently treatment-resistant HTN; (6) the definition usually directly incorporates BP cut-offs for systolic BP (sBP) and diastolic BP (dBP) making the diagnosis temporary; (7) stress is not included in the exclusion strategy for resistant HTN; (8) there is potentially a need to introduce a category of recovered resistant HTN; (9) to what degree do healthy lifestyle measures have to be fulfilled to consider it as sufficient to change the diagnosis from "apparent treatment-resistant HTN" to the "resistant HTN"; (10) sBP values normal-for-the-age for 61 and 81 year old patients in some guidelines fulfill the criterion for resistant HTN; (11) it probably ought to read "In the absence of contraindications and compelling indications…" in the others. We believe that it is better to use the phrase "above the target BP" for the definition of (treatment) resistant HTN, because the whole story of resistant HTN is related to non-responders to antihypertensive treatment. Therefore, as we treat to target and not to normal values, it is appropriate to define resistant HTN as an insufficiency to reach the target BP values. Moreover, the definition of (treatment) resistant HTN should not be universal for every patient with HTN, but it should be age-related: (treatment) resistant HTN is elevated BP over the target/normal BP values. Using this modification, there will be no need to automatically change the definition of resistant HTN when we change the BP targets in the future.

Compliance to Multidisciplinary Lifestyle Intervention Decreases Blood Pressure in Patients with Resistant Hypertension: A Cross-Sectional Pilot Study

Hypertension is a common chronic medical condition. Treatment is not satisfactory in a significant proportion of patients with primary hypertension, despite the concurrent use of three or more medications with different mechanisms of action. Such treatment-resistant hypertension is a clinical challenge associated with poor prognosis and needs further investigation. The efficacy of lifestyle changes has not been established yet in patients with resistant hypertension, and educational efforts appear clinically irrelevant in patients who must achieve behavioral changes without supervision. A 6-month multidisciplinary pilot intervention enrolled 50 patients with established resistant hypertension. The aims were: (1) to examine whether intensive and supervised lifestyle changes contribute to decreasing blood pressure in this condition, and (2) to identify which components affect compliance and feasibility. The program provided intensive changes in nutrition, physical exercise, and control of sleep disturbances supervised by nutritionists, physiotherapists, and psychologists. Nurses and pharmacists followed up on adherence to the antihypertensive medication. The primary outcome was 24 h blood pressure control. Data in patients with full compliance (n = 30) indicate that lifestyle modifications in resistant hypertension significantly reduced 24 h both systolic and diastolic blood pressure (p < 0.01), body mass index (p < 0.01), medication burden (p = 0.04), improving physical fitness, and cardiovascular risk markers such as heart rate (p = 0.01) and augmentation index (p = 0.02). The adherence to the intervention was moderate, with an attrition rate of 12%. A modified version reducing visits and explorations will likely improve compliance and can be used to assess the long-term maintenance of these benefits in managing resistant hypertension by diverse healthcare providers.

Dual endothelin antagonist aprocitentan for resistant hypertension (PRECISION): a multicentre, blinded, randomised, parallel-group, phase 3 trial

BACKGROUND

Resistant hypertension is associated with increased cardiovascular risk. The endothelin pathway has been implicated in the pathogenesis of hypertension, but it is currently not targeted therapeutically, thereby leaving this relevant pathophysiological pathway unopposed with currently available drugs. The aim of the study was to assess the blood pressure lowering efficacy of the dual endothelin antagonist aprocitentan in patients with resistant hypertension.

METHODS

PRECISION was a multicentre, blinded, randomised, parallel-group, phase 3 study, which was done in hospitals or research centres in Europe, North America, Asia, and Australia. Patients were eligible for randomisation if their sitting systolic blood pressure was 140 mm Hg or higher despite taking standardised background therapy consisting of three antihypertensive drugs, including a diuretic. The study consisted of three sequential parts: part 1 was the 4-week double-blind, randomised, and placebo-controlled part, in which patients received aprocitentan 12·5 mg, aprocitentan 25 mg, or placebo in a 1:1:1 ratio; part 2 was a 32-week single (patient)-blind part, in which all patients received aprocitentan 25 mg; and part 3 was a 12-week double-blind, randomised, and placebo-controlled withdrawal part, in which patients were re-randomised to aprocitentan 25 mg or placebo in a 1:1 ratio. The primary and key secondary endpoints were changes in unattended office systolic blood pressure from baseline to week 4 and from withdrawal baseline to week 40, respectively. Secondary endpoints included 24-h ambulatory blood pressure changes. The study is registered on ClinicalTrials.gov, NCT03541174.

FINDINGS

The PRECISION study was done from June 18, 2018, to April 25, 2022. 1965 individuals were screened and 730 were randomly assigned. Of these 730 patients, 704 (96%) completed part 1 of the study; of these, 613 (87%) completed part 2 and, of these, 577 (94%) completed part 3 of the study. The least square mean (SE) change in office systolic blood pressure at 4 weeks was -15·3 (SE 0·9) mm Hg for aprocitentan 12·5 mg, -15·2 (0·9) mm Hg for aprocitentan 25 mg, and -11·5 (0·9) mm Hg for placebo, for a difference versus placebo of -3·8 (1·3) mm Hg (97·5% CI -6·8 to -0·8, p=0·0042) and -3·7 (1·3) mm Hg (-6·7 to -0·8; p=0·0046), respectively. The respective difference for 24 h ambulatory systolic blood pressure was -4·2 mm Hg (95% CI -6·2 to -2·1) and -5·9 mm Hg (-7·9 to -3·8). After 4 weeks of withdrawal, office systolic blood pressure significantly increased with placebo versus aprocitentan (5·8 mm Hg, 95% CI 3·7 to 7·9, p<0·0001). The most frequent adverse event was mild-to-moderate oedema or fluid retention, occurring in 9%, 18%, and 2% for patients receiving aprocitentan 12·5 mg, 25 mg, and placebo, during the 4-week double-blind part, respectively. This event led to discontinuation in seven patients treated with aprocitentan. During the trial, a total of 11 treatment-emergent deaths occurred, none of which were regarded by the investigators to be related to study treatment.

INTERPRETATION

In patients with resistant hypertension, aprocitentan was well tolerated and superior to placebo in lowering blood pressure at week 4 with a sustained effect at week 40.

FUNDING

Idorsia Pharmaceuticals and Janssen Biotech.

Identifying and treating resistant hypertension in PRECISION: A randomized long-term clinical trial with aprocitentan

The design and baseline data of the PRECISION study, which evaluates the effect of the dual endothelin receptor antagonist aprocitentan on blood pressure (BP) in patients with resistant hypertension (RHT) are presented. The study is a blinded, randomized, parallel-group Phase 3 study and its three-part design assesses the short-term and sustained long-term effects of aprocitentan on BP. Results are expected in 2022. Patients with uncontrolled BP (measured as unattended automated office BP) despite the use of three or more antihypertensive medications for at least 1 year were screened. They were switched to a single-tablet triple fixed combination antihypertensive therapy for at least 4 weeks before entering a single-blind placebo run-in period. The 4-week placebo run-in period further excluded placebo responders. The randomization period consisted of three sequential parts: (1) a 4-week double-blind part with aprocitentan 12.5 mg, 25 mg, or placebo (1:1:1 ratio); (2) a 32-week single-blind part with aprocitentan 25 mg; and (3) a 12-week randomized withdrawal part with aprocitentan 25 mg or placebo (1:1 ratio). The purpose was to demonstrate the BP lowering effect of aprocitentan in RHT (Part 1) and the persistence of this effect (Parts 2 and 3). Out of 1965 screened patients, 730 were randomized resulting in an overall inclusion failure rate of 62.8%. The most common reason for exclusion (44.4% of all screened patients) was failure to meet the BP inclusion criteria. These results underline the high proportion of pseudoresistant hypertension among patients referred for RHT.