Finerenone, a novel selective nonsteroidal mineralocorticoid receptor antagonist protects from rat cardiorenal injury

Pharmacokinetics, distribution, and disposition of esaxerenone, a novel, highly potent and selective non-steroidal mineralocorticoid receptor antagonist, in rats and monkeys

1. Esaxerenone (CS-3150) is a novel non-steroidal mineralocorticoid receptor antagonist. The pharmacokinetics, tissue distribution, excretion, and metabolism of esaxerenone were evaluated in rats and monkeys. 2. Following intravenous dosing of esaxerenone at 0.1-3 mg/kg, the total body clearance and the volume of distribution were 3.53-6.69 mL/min/kg and 1.47-2.49 L/kg, respectively, in rats, and 2.79-3.69 mL/min/kg and 1.34-1.54 L/kg, respectively, in monkeys. The absolute oral bioavailability was 61.0-127% in rats and 63.7-73.8% in monkeys. 3. After oral administration of [¹⁴C]esaxerenone, the radioactivity was distributed widely to tissues, with the exception of a low distribution to the central nervous system. Both in rats and in monkeys, following oral administration of [¹⁴C]esaxerenone the main excretion route of the radioactivity was feces. 4. Five initial metabolic pathways in rats and monkeys were proposed to be N-dealkylation, carboxylation, hydroxymethylation, O-glucuronidation, and O-sulfation. The oxidized metabolism was predominant in rats, while both oxidation and glucuronidation were predominant in monkeys.

Third-generation Mineralocorticoid Receptor Antagonists: Why Do We Need a Fourth?

The first mineralocorticoid receptor (MR) antagonist, spironolactone, was developed almost 60 years ago to treat primary aldosteronism and pathological edema. Its use waned in part because of its lack of selectivity. Subsequently, knowledge of the scope of MR function was expanded along with clinical evidence of the therapeutic importance of MR antagonists to prevent the ravages of inappropriate MR activation. Forty-two years elapsed between the first and MR-selective second generation of MR antagonists. Fifteen years later, despite serious shortcomings of the existing antagonists, a third-generation antagonist has yet to be marketed. Progress has been slowed by the lack of appreciation of the large variety of cell types that express the MR and its diverse cell-type-specific actions, and also its unique complex interaction actions at the molecular level. New MR antagonists should preferentially target the inflammatory and fibrotic effects of MR and perhaps its excitatory effects on sympathetic nervous system, but not the renal tubular epithelium or neurons of the cortex and hippocampus. This review briefly describes efforts to develop a third-generation MR antagonist and why fourth generation antagonists and selective agonists based on structural determinants of tissue and ligand-specific MR activation should be contemplated.

Emerging Roles of the Mineralocorticoid Receptor in Pathology: Toward New Paradigms in Clinical Pharmacology

The mineralocorticoid receptor (MR) and its ligand aldosterone are the principal modulators of hormone-regulated renal sodium reabsorption. In addition to the kidney, there are several other cells and organs expressing MR, in which its activation mediates pathologic changes, indicating potential therapeutic applications of pharmacological MR antagonism. Steroidal MR antagonists have been used for decades to fight hypertension and more recently heart failure. New therapeutic indications are now arising, and nonsteroidal MR antagonists are currently under development. This review is focused on nonclassic MR targets in cardiac, vascular, renal, metabolic, ocular, and cutaneous diseases. The MR, associated with other risk factors, is involved in organ fibrosis, inflammation, oxidative stress, and aging; for example, in the kidney and heart MR mediates hormonal tissue-specific ion channel regulation. Genetic and epigenetic modifications of MR expression/activity that have been documented in hypertension may also present significant risk factors in other diseases and be susceptible to MR antagonism. Excess mineralocorticoid signaling, mediated by aldosterone or glucocorticoids binding, now appears deleterious in the progression of pathologies that may lead to end-stage organ failure and could therefore benefit from the repositioning of pharmacological MR antagonists.

Pharmacology of heart failure: From basic science to novel therapies

Chronic heart failure is one of the leading causes for hospitalization in the United States and Europe, and is accompanied by high mortality. Current pharmacological therapy of chronic heart failure with reduced ejection fraction is largely based on compounds that inhibit the detrimental action of the adrenergic and the renin-angiotensin-aldosterone systems on the heart. More than one decade after spironolactone, two novel therapeutic principles have been added to the very recently released guidelines on heart failure therapy: the HCN-channel inhibitor ivabradine and the combined angiotensin and neprilysin inhibitor valsartan/sacubitril. New compounds that are in phase II or III clinical evaluation include novel non-steroidal mineralocorticoid receptor antagonists, guanylate cyclase activators or myosine activators. A variety of novel candidate targets have been identified and the availability of gene transfer has just begun to accelerate translation from basic science to clinical application. This review provides an overview of current pharmacology and pharmacotherapy in chronic heart failure at three stages: the updated clinical guidelines of the American Heart Association and the European Society of Cardiology, new drugs which are in clinical development, and finally innovative drug targets and their mechanisms in heart failure which are emerging from preclinical studies will be discussed.

New agents modulating the renin-angiotensin-aldosterone system-Will there be a new therapeutic option?

The renin-angiotensin-aldosterone system (RAAS) is more complex than it was originally regarded. According to the current subject knowledge, there are two main axes of the RAAS: (1) angiotensin-converting enzyme (ACE)-angiotensin II-AT₁ receptor axis and (2) ACE2-angiotensin-(1-7)-Mas receptor axis. The activation of the first axis leads to deleterious effects, including vasoconstriction, endothelial dysfunction, thrombosis, inflammation, and fibrosis; therefore, blocking the components of this axis is a highly rational and commonly used therapeutic procedure. The ACE2-Ang-(1-7)-Mas receptor axis has a different role, since it often opposes the effects induced by the classical ACE-Ang II-AT₁ axis. Once the positive effects of the ACE2-Ang-(1-7)-Mas axis were discovered, the alternative ways of pharmacotherapy activating this axis of RAAS appeared. This article briefly describes new molecules affecting the RAAS, namely: recombinant human ACE2, ACE2 activators, angiotensin-(1-7) peptide and non-peptide analogs, aldosterone synthase inhibitors, and the third and fourth generation of mineralocorticoid receptor antagonists. The results of the experimental and clinical studies are encouraging, which leads us to believe that these new molecules can support the treatment of cardiovascular diseases as well as cardiometabolic disorders.

A randomized controlled study of finerenone vs. eplerenone in patients with worsening chronic heart failure and diabetes mellitus and/or chronic kidney disease

AIMS

To evaluate oral doses of the non-steroidal mineralocorticoid receptor antagonist finerenone given for 90 days in patients with worsening heart failure and reduced ejection fraction and chronic kidney disease and/or diabetes mellitus.

METHODS AND RESULTS

Miner Alocorticoid Receptor antagonist Tolerability Study-Heart Failure (ARTS-HF) was a randomized, double-blind, phase 2b multicentre study (ClinicalTrials.gov: NCT01807221). Of 1286 screened patients, 1066 were randomized. Patients received oral, once-daily finerenone (2.5, 5, 7.5, 10, or 15 mg, uptitrated to 5, 10, 15, 20, or 20 mg, respectively, on Day 30) or eplerenone (25 mg every other day, increased to 25 mg once daily on Day 30, and to 50 mg once daily on Day 60) for 90 days. The primary endpoint was the percentage of individuals with a decrease of >30% in plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) from baseline to Day 90. A key exploratory endpoint was a composite clinical endpoint of death from any cause, cardiovascular hospitalizations, or emergency presentation for worsening HF until Day 90. Mean age ranged from 69.2 to 72.5 years in different treatment groups (standard deviation 9.7-10.6 years). Decreases in NT-proBNP of >30% from baseline occurred in 37.2% of patients in the eplerenone group and 30.9, 32.5, 37.3, 38.8, and 34.2% in the 2.5→5, 5→10, 7.5→15, 10→20, and 15→20 mg finerenone groups, respectively (P = 0.42-0.88). Except for the 2.5→5 mg finerenone group, the composite clinical endpoint occurred numerically less frequently in finerenone-treated patients compared with eplerenone; this difference reached nominal statistical significance in the 10→20 mg group (hazard ratio 0.56, 95% confidence interval, CI, 0.35; 0.90; nominal P = 0.02), despite the fact that this phase 2 study was not designed to detect statistical significant differences. A potassium level increase to ≥5.6 mmol/L at any time point occurred in 4.3% of patients, with a balanced distribution among all treatment groups.

CONCLUSION

Finerenone was well tolerated and induced a 30% or greater decrease in NT-proBNP levels in a similar proportion of patients to eplerenone. The finding of reduced clinical events in the finerenone 10→20 mg group should be further explored in a large outcomes trial.

Role of the Renin-Angiotensin-Aldosterone System beyond Blood Pressure Regulation: Molecular and Cellular Mechanisms Involved in End-Organ Damage during Arterial Hypertension

Arterial hypertension is a common condition worldwide and an important predictor of several complicated diseases. Arterial hypertension can be triggered by many factors, including physiological, genetic, and lifestyle causes. Specifically, molecules of the renin-angiotensin-aldosterone system not only play important roles in the control of blood pressure, but they are also associated with the genesis of arterial hypertension, thus constituting a need for pharmacological interventions. Chronic high pressure generates mechanical damage along the vascular system, heart, and kidneys, which are the principal organs affected in this condition. In addition to mechanical stress, hypertension-induced oxidative stress, chronic inflammation, and the activation of reparative mechanisms lead to end-organ damage, mainly due to fibrosis. Clinical trials have demonstrated that renin-angiotensin-aldosterone system intervention in hypertensive patients lowers morbidity/mortality and inflammatory marker levels as compared to placebo patients, evidencing that this system controls more than blood pressure. This review emphasizes the detrimental effects that a renin-angiotensin-aldosterone system (RAAS) imbalance has on health considerations above and beyond high blood pressure, such as fibrotic end-organ damage.

Translational In Vivo Models for Cardiovascular Diseases

Cardiovascular diseases are still the first leading cause of death and morbidity in developed countries. Experimental cardiology research and preclinical drug development in cardiology call for appropriate and especially clinically relevant in vitro and in vivo studies. The use of animal models has contributed to expand our knowledge and our understanding of the underlying mechanisms and accordingly provided new approaches focused on the improvement of diagnostic and treatment strategies of various cardiac pathologies.Numerous animal models in different species as well as in small and large animals have been developed to address cardiovascular complications, including heart failure, pulmonary hypertension, and thrombotic diseases. However, a perfect model of heart failure or other indications that reproduces every aspect of the natural disease does not exist. The complexity and heterogeneity of cardiac diseases plus the influence of genetic and environmental factors limit to mirror a particular disease with a single experimental model.Thus, drug development in the field of cardiology is not only very challenging but also inspiring; therefore animal models should be selected that reflect as best as possible the disease being investigated. Given the wide range of animal models, reflecting critical features of the human pathophysiology available nowadays increases the likelihood of the translation to the patients. Furthermore, this knowledge and the increase of the predictive value of preclinical models help us to find more efficient and reliable solutions as well as better and innovative treatment strategies for cardiovascular diseases.

Nonsteroidal antagonists of the mineralocorticoid receptor

PURPOSE OF REVIEW

The broad clinical use of steroidal mineralocorticoid receptor antagonists (MRAs) is limited by the potential risk of inducing hyperkalemia when given on top of renin-angiotensin system blockade. Drug discovery campaigns have been launched aiming for the identification of nonsteroidal MRAs with an improved safety profile. This review analyses the evidence for the potential of improved safety profiles of nonsteroidal MRAs and the current landscape of clinical trials with nonsteroidal MRAs.

RECENT FINDINGS

At least three novel nonsteroidal MRAs have reportedly demonstrated an improved therapeutic index (i.e. less risk for hyperkalemia) in comparison to steroidal antagonists in preclinical models. Five pharmaceutical companies have nonsteroidal MRAs in clinical development with a clear focus on the treatment of chronic kidney diseases. No clinical data have been published so far for MT-3995 (Mitsubishi), SC-3150 (Daiichi-Sankyo), LY2623091 (Eli Lilly) and PF-03882845 (Pfizer). In contrast, data from two clinical phase II trials are available for finerenone (Bayer) which demonstrated safety and efficacy in patients with heart failure and additional chronic kidney diseases, and significantly reduced albuminuria in patients with diabetic nephropathy. Neither hyperkalemia nor reductions in kidney function were limiting factors to its use.

SUMMARY

Novel, nonsteroidal MRAs are currently tested in clinical trials. Based on preclinical and first clinical data, these nonsteroidal MRAs might overcome the limitations of today's steroidal antagonists.

A Randomized Controlled Study of Finerenone vs. Eplerenone in Japanese Patients With Worsening Chronic Heart Failure and Diabetes and/or Chronic Kidney Disease

BACKGROUND

Finerenone, a nonsteroidal mineralocorticoid receptor antagonist, was evaluated in Japanese patients with heart failure (HF) with reduced ejection fraction and chronic kidney disease and/or diabetes mellitus.

METHODS AND RESULTS

ARTS-HF Japan was a randomized, double-blind, phase 2b study. Patients (n=72) received oral, once-daily (o.d.) finerenone (2.5, 5, 7.5, 10 or 15 mg, up-titrated to 5, 10, 15, 20, or 20 mg, respectively, on day 30) or eplerenone (25 mg every other day, increased to 25 mg o.d. on day 30, and 50 mg on day 60) for 90 days. The primary endpoint was the proportion of individuals with a decrease of >30% in plasma NT-proBNP at day 90. Safety endpoints included the incidence of hyperkalemia. Decreases in NT-proBNP occurred in 23.1% of patients in the eplerenone group and 15.4%, 23.1%, 45.5%, 27.3% and 45.5% in the 2.5→5 mg, 5→10 mg, 7.5→15 mg, 10→20 mg and 15→20 mg finerenone groups, respectively (all P=NS). Mean changes in serum potassium levels were similar between groups.

CONCLUSIONS

Because of the small sample size, limited conclusions can be drawn. Considering the results of ARTS-HF and that finerenone was well tolerated in Japanese patients in ARTS-HF Japan, the safety and efficacy of finerenone should be further explored in a large outcomes trial including Japanese patients. (Circ J 2016; 80: 1113-1122).

The safety of mineralocorticoid receptor antagonists (MRAs) in patients with heart failure

INTRODUCTION

Mineralocorticoid receptor antagonists (MRAs) have been accorded a class 1 indication for patients with chronic heart failure and a reduced left ventricular ejection fraction (HFREF) in both European and American guidelines. Uptake, however, has been less than optimal largely due to concerns about their safety, in particular the risk of hyperkalemia and renal dysfunction.

AREAS COVERED

This review presents the current state of affairs regarding the safety of MRAs in heart failure with reduced ejection fraction.

EXPERT OPINION

Careful patient selection and adherence to guideline-recommended inclusion and exclusion criteria, dosing, and serial monitoring of serum potassium and renal function, along with patient education regarding the potassium content of common foods, should minimize these risks and allow increased use of MRAs. Additionally, this may also result in a further reduction in cardiovascular mortality and hospitalizations for heart failure. The development of new non-steroidal MRAs, and especially new potassium binding molecules that are well tolerated and effective, hold the promise for increased safety and, therefore, increased and more prolonged use of MRAs in patients with heart failure, especially those with chronic kidney disease, diabetes mellitus, and the elderly.

Mineralocorticoid receptor antagonists-pharmacodynamics and pharmacokinetic differences

Mineralocorticoid receptor antagonists (MRAs) are best known as potassium-sparing diuretics due to their blockade of aldosterone action in renal epithelial tissues. They are also beneficial for the treatment of heart failure, primarily due to effects in non-epithelial tissues. Currently there are only two steroidal MRAs that have been approved for use; spironolactone (and its active metabolite canrenone) and eplerenone. However, the search is on for novel generations of MRAs with increased potency and tissue selectivity. A number of novel non-steroidal compounds are in preclinical and early development, with one agent moving to phase III trials. The development of these agents and the mechanisms for their pharmacologic superiority compared to earlier generations of MRAs will be discussed in this review.

Pharmacokinetics, safety and tolerability of the novel, selective mineralocorticoid receptor antagonist finerenone - results from first-in-man and relative bioavailability studies

The safety, tolerability and pharmacokinetics of the selective nonsteroidal mineralocorticoid receptor antagonist finerenone were evaluated in healthy male volunteers in two randomized, single-centre studies. Study 1 was a first-in-man, single-blinded, placebo-controlled, parallel-group, dose-escalation study. Fasted participants (n = 45) received single oral doses of finerenone 1-40 mg polyethylene glycol (PEG) solution or placebo. Study 2 was a relative bioavailability study comparing a finerenone 10 mg immediate-release (IR) tablet with finerenone 10 mg PEG solution in the fasted state, investigating the effect of a high-fat/high-calorie meal on the pharmacokinetics of the IR tablet and assessing a further dose escalation to finerenone 80 mg (eight × finerenone 10 mg IR tablets), in an open-label, fourfold crossover design (n = 15). Finerenone was rapidly absorbed from PEG solution (median time to maximum plasma concentration [tmax ]: 0.500-1.00 h), exhibited dose-linear pharmacokinetics and was rapidly eliminated from plasma (geometric mean terminal half-life [t½ ]: 1.70-2.83 h). Finerenone IR tablets demonstrated similar pharmacokinetics (median tmax : 0.750-2.50 h; geometric mean t½ : 1.89-4.29 h) with, however, enhanced bioavailability versus PEG solution (least-squares mean tablet/solution ratio of 187% for area under the plasma-concentration curve [AUC] and maximum plasma concentration [Cmax ]). High-fat/high-calorie food affected the rate but not the extent of finerenone absorption. Finerenone was well tolerated and did not influence clinical laboratory parameters, blood pressure, heart rate, urinary electrolytes or neurohormones, including serum aldosterone and angiotensin II. In conclusion, finerenone has favourable pharmacokinetics and tolerability in healthy men, and is suitable for dosing independent of food intake.

Rationale and design of MinerAlocorticoid Receptor antagonist Tolerability Study-Heart Failure (ARTS-HF): a randomized study of finerenone vs. eplerenone in patients who have worsening chronic heart failure with diabetes and/or chronic kidney disease

AIMS

To investigate the safety and potential efficacy of the novel non-steroidal mineralocorticoid receptor antagonist finerenone in patients with worsening chronic heart failure and reduced left ventricular ejection fraction (HFrEF) and at high risk of hyperkalaemia and worsening renal dysfunction.

METHODS AND RESULTS

The MinerAlocorticoid Receptor antagonist Tolerability Study-Heart Failure (ARTS-HF; NCT01807221) is a multicentre, randomized, double-blind, active-comparator-controlled, six-parallel-group, phase 2b dose-finding study. In total, 1060 patients with HFrEF and concomitant type 2 diabetes mellitus and/or chronic kidney disease (CKD) will be randomized within 7 days of emergency presentation to hospital for worsening chronic HF to receive finerenone (one of five doses in the range 2.5-20.0 mg once daily) or eplerenone (25 mg every second day to 50 mg once daily for 90 days). The primary objective is to investigate the safety and potential efficacy (measured as the percentage of individuals with a decrease in plasma N-terminal pro-B-type natriuretic peptide [NT-proBNP] of more than 30% relative to baseline at day 90 ± 2) of different oral doses of finerenone compared with eplerenone. Other objectives are to assess the effects of finerenone on a composite clinical endpoint (death from any cause, cardiovascular hospitalizations, or emergency presentations for worsening chronic HF), and on changes in health-related quality of life from baseline.

CONCLUSIONS

ARTS-HF is the first phase 2b clinical trial to investigate the effects of finerenone on plasma NT-proBNP in a high-risk population of patients who have worsening chronic HF with type 2 diabetes mellitus and/or CKD presenting at the emergency department.

CS-3150, a novel non-steroidal mineralocorticoid receptor antagonist, prevents hypertension and cardiorenal injury in Dahl salt-sensitive hypertensive rats

The present study was designed to evaluate the antihypertensive and cardiorenal protective effects of CS-3150, a novel non-steroidal mineralocorticoid receptor antagonist, in Dahl salt-sensitive hypertensive rats (DS rats), and to compare the effects with spironolactone and eplerenone. DS rats were fed a control diet (0.3% NaCl) or high salt diet (8% NaCl) from 7 weeks of age. CS-3150 (0.25-2mg/kg), spironolactone (10-100mg/kg) or eplerenone (10-100mg/kg) were orally administered once a day to DS rats fed a high salt diet for 7 weeks. The high salt diet significantly increased systolic blood pressure, which was prevented by treatment with CS-3150 in a dose-dependent manner with no hyperkalemia (>5.5mEq/L). The antihypertensive effect of CS-3150 (0.5mg/kg) was equivalent to that of spironolactone (100mg/kg) and eplerenone (100mg/kg). CS-3150 also suppressed proteinuria and renal hypertrophy induced by the high salt diet. Histopathological examination of kidneys showed that CS-3150 markedly ameliorated glomerulosclerosis, tubular injury and tubulointerstitial fibrosis. In addition, CS-3150 inhibited left ventricular hypertrophy and elevation of plasma brain natriuretic peptide level. In contrast, the cardiorenal protective effects of spironolactone or eplerenone were partial, and the dose-dependency was not clear, especially in eplerenone-treated rats. These results indicate that chronic treatment with CS-3150 exerts antihypertensive and cardiorenal protective effects in a DS hypertensive rat model, and its potency is much superior to that of spironolactone or eplerenone. Thus, CS-3150 could be a promising agent for the treatment of hypertension and cardiorenal disorders.

New medical therapies for heart failure

Heart failure (HF) can rightfully be called the epidemic of the 21(st) century. Historically, the only available medical treatment options for HF have been diuretics and digoxin, but the capacity of these agents to alter outcomes has been brought into question by the scrutiny of modern clinical trials. In the past 4 decades, neurohormonal blockers have been introduced into clinical practice, leading to marked reductions in morbidity and mortality in chronic HF with reduced left ventricular ejection fraction (LVEF). Despite these major advances in pharmacotherapy, our understanding of the underlying disease mechanisms of HF from epidemiological, clinical, pathophysiological, molecular, and genetic standpoints remains incomplete. This knowledge gap is particularly evident with respect to acute decompensated HF and HF with normal (preserved) LVEF. For these clinical phenotypes, no drug has been shown to reduce long-term clinical event rates substantially. Ongoing developments in the pharmacotherapy of HF are likely to challenge our current best-practice algorithms. Novel agents for HF therapy include dual-acting neurohormonal modulators, contractility-enhancing agents, vasoactive and anti-inflammatory peptides, and myocardial protectants. These novel compounds have the potential to enhance our armamentarium of HF therapeutics.

Combination use of medicines from two classes of renin-angiotensin system blocking agents: risk of hyperkalemia, hypotension, and impaired renal function

European and United States regulatory agencies recently issued warnings against the use of dual renin-angiotensin system (RAS) blockade therapy through the combined use of angiotensin-converting enzyme inhibitors (ACEIs), angiotensin II receptor blockers (ARBs) or aliskiren in any patient, based on absence of benefit for most patients and increased risk of hyperkalemia, hypotension, and renal failure. Special emphasis was made not to use these combinations in patients with diabetic nephropathy. The door was left open to therapy individualization, especially for patients with heart failure, when the combined use of an ARB and ACEI is considered absolutely essential, although renal function, electrolytes and blood pressure should be closely monitored. Mineralocorticoid receptor antagonists were not affected by this warning despite increased risk of hyperkalemia. We now critically review the risks associated with dual RAS blockade and answer the following questions: What safety issues are associated with dual RAS blockade? Can the safety record of dual RAS blockade be improved? Is it worth trying to improve the safety record of dual RAS blockade based on the potential benefits of the combination? Is dual RAS blockade dead? What is the role of mineralocorticoid antagonists in combination with other RAS blocking agents: RAAS blockade?

Finerenone Impedes Aldosterone-dependent Nuclear Import of the Mineralocorticoid Receptor and Prevents Genomic Recruitment of Steroid Receptor Coactivator-1

Aldosterone regulates sodium homeostasis by activating the mineralocorticoid receptor (MR), a member of the nuclear receptor superfamily. Hyperaldosteronism leads todeleterious effects on the kidney, blood vessels, and heart. Although steroidal antagonists such as spironolactone and eplerenone are clinically useful for the treatment of cardiovascular diseases, they are associated with several side effects. Finerenone, a novel nonsteroidal MR antagonist, is presently being evaluated in two clinical phase IIb trials. Here, we characterized the molecular mechanisms of action of finerenone and spironolactone at several key steps of the MR signaling pathway. Molecular modeling and mutagenesis approaches allowed identification of Ser-810 and Ala-773 as key residues for the high MR selectivity of finerenone. Moreover, we showed that, in contrast to spironolactone, which activates the S810L mutant MR responsible for a severe form of early onset hypertension, finerenone displays strict antagonistic properties. Aldosterone-dependent phosphorylation and degradation of MR are inhibited by both finerenone and spironolactone. However, automated quantification of MR subcellular distribution demonstrated that finerenone delays aldosterone-induced nuclear accumulation of MR more efficiently than spironolactone. Finally, chromatin immunoprecipitation assays revealed that, as opposed to spironolactone, finerenone inhibits MR, steroid receptor coactivator-1, and RNA polymerase II binding at the regulatory sequence of the SCNN1A gene and also remarkably reduces basal MR and steroid receptor coactivator-1 recruitment, unraveling a specific and unrecognized inactivating mechanism on MR signaling. Overall, our data demonstrate that the highly potent and selective MR antagonist finerenone specifically impairs several critical steps of the MR signaling pathway and therefore represents a promising new generation MR antagonist.

Small molecule and peptide therapies for chronic heart failure: a patent review (2011 - 2014)

INTRODUCTION

Chronic heart failure (CHF) is the long-term inability of the heart to meet circulatory demands under normal conditions. Effects of CHF can include increased blood volume, increased vascular resistance and compromised contractility leading to fluid retention, dyspnea and fatigue. Current standard of care for chronic systolic heart failure is directed towards managing hypoperfusion through the renin-angiotensin-aldosterone and sympathetic nervous systems. Treatment may also involve reversal of maladaptive cardiac remodeling and prevention of life-threatening arrhythmias.

AREAS COVERED

This review highlights small molecule and peptidic agents for the treatment of CHF with patents published between 2011 and 2014. Targets are subdivided into inotropic agents, ventricular remodeling, diuretics and the renin-angiotensin-aldosterone system.

EXPERT OPINION

CHF represents a large, unmet medical need where improved therapies are needed. The renin-angiotensin-aldosterone system pathway continues to be a major source of new therapies for CHF with new inotropic therapies emerging. Promising initial clinical results for a few approaches combined with the expectation of additional clinical results in the near future make this an exciting time in the pursuit of new treatments for CHF.

Finerenone : third-generation mineralocorticoid receptor antagonist for the treatment of heart failure and diabetic kidney disease

INTRODUCTION

The mineralocorticoid receptor antagonists (MRAs) spironolactone and eplerenone reduce the risk of hospitalizations and mortality in patients with heart failure (HF) with reduced ejection fraction (HFrEF), and attenuate progression of diabetic kidney disease. However, their use is limited by the fear of inducing hyperkalemia, especially in patients with renal dysfunction. Finerenone is a novel nonsteroidal MRA, with higher selectivity toward the mineralocorticoid receptor (MR) compared to spironolactone and stronger MR-binding affinity than eplerenone.

AREAS COVERED

This paper discusses the chemistry, pharmacokinetics, clinical efficacy and safety of finerenone.

EXPERT OPINION

The selectivity and greater binding affinity of finerenone to the MR may reduce the risk of hyperkalemia and renal dysfunction and thereby overcome the reluctance to start and uptitrate MRAs in patients with HF and diabetic kidney disease. Studies conducted in patients with HFrEF and moderate chronic kidney disease and diabetic kidney disease, showed promising results. Phase III trials will have to show whether finerenone might become the third-generation MRA for the treatment of HF and diabetic kidney disease.

Outcomes of drug-based and surgical treatments for primary aldosteronism

Treatments for primary aldosteronism (PA) aim to correct or prevent the deleterious consequences of hyperaldosteronism: hypertension, hypokalemia, and direct target organ damage. Patients with unilateral PA considered fit for surgery can undergo laparoscopic adrenalectomy, which significantly decreases blood pressure (BP) and medications in most cases and cures hypertension in about 40%. Mineralocorticoid receptor antagonists (MRA) are used to treat patients with bilateral PA and those with unilateral PA if surgery is not possible or not desired. Spironolactone is more potent than eplerenone, but high doses are poorly tolerated in men. MRA can be replaced or complemented with epithelial sodium channel blockers, such as amiloride. Thiazide diuretics and calcium channel blockers are used when the first-line drugs are insufficient to control BP. Dietary sodium restriction should be implemented in all cases because the deleterious consequences of hyperaldosteronism are dependent on salt loading. Several studies comparing the results of surgery and MRA have reported no differences in terms of BP, serum potassium concentration, or cardiovascular and kidney outcomes, although the benefits of treatment tend to be observed sooner with surgery. Patients with PA display relative glomerular hyperfiltration, which is reversed by specific treatment, revealing CKD in 30% of patients. However, further kidney damage is lessened by the treatment of PA.

DSR-71167, a novel mineralocorticoid receptor antagonist with carbonic anhydrase inhibitory activity, separates urinary sodium excretion and serum potassium elevation in rats

Mineralocorticoid receptor (MR) antagonists, such as spironolactone (SPI) and eplerenone (EPL), are useful for treating hypertension and heart failure. However, these two agents have the serious side effect of hyperkalemia. We hypothesized that adding the ability to inhibit carbonic anhydrase (CA) would reduce the risk of hyperkalemia associated with MR antagonists. We investigated the profiles of DSR-71167 [2-([(2,2-difluoroethyl)amino]methyl)-2'-fluoro-N-(3-methoxy-4-sulfamoylphenyl)biphenyl-4-carboxamide hydrochloride; an MR antagonist with weak CA inhibitory activity] with regard to antimineralocorticoid actions by examining relationships between the urinary excretion of sodium (index of antimineralocorticoid action) in deoxycorticosterone acetate-treated rats and elevation of serum levels of potassium in potassium-loaded rats compared with a DSR-71167 derivative without CA inhibition (2-(hydroxymethyl)-N-[4-(methylsulfonyl)phenyl]-2'-(trifluoromethyl)biphenyl-4-carboxamide), SPI, and EPL. DSR-71167 dose-dependently increased urinary excretion of sodium in deoxycorticosterone acetate-treated rats without elevating serum levels of potassium in potassium-loaded rats. 2-(Hydroxymethyl)-N-[4-(methylsulfonyl)phenyl]-2'-(trifluoromethyl)biphenyl-4-carboxamide, SPI, and EPL elevated serum levels of potassium significantly in potassium-loaded rats at doses that increased MR inhibitory activity. We confirmed that DSR-71167 significantly increases urinary bicarbonate and decreases blood bicarbonate, as pharmacodynamic markers of CA inhibition, in intact rats. Chronic DSR-71167 administration showed antihypertensive effects in high salt-loaded Dahl hypertensive rats. These results demonstrate that DSR-71167 is a novel type of MR antagonist, with CA inhibitory activity, which is expected to become a safer MR antagonist with a low potential risk for hyperkalemia.

Novel RAAS agonists and antagonists: clinical applications and controversies

The renin-angiotensin-aldosterone system (RAAS) regulates blood pressure homeostasis and vascular injury and repair responses. The RAAS was originally thought to be an endocrine system critically important in regulating blood pressure homeostasis. Yet, important local forms of the RAAS have been described in many tissues, which are mostly independent of the systemic RAAS. These systems have been associated with diverse physiological functions, but also with inflammation, fibrosis and target-organ damage. Pharmacological modulation of the RAAS has brought about important advances in preventing morbidity and mortality associated with cardiovascular disease. Yet, traditional RAAS blockers such as angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) only reduce the risk of disease progression in patients with established cardiovascular or renal disease by ∼20% compared with other therapies. As more components of the RAAS are described, other potential therapeutic targets emerge, which could provide improved cardiovascular and renal protection beyond that provided by an ACE inhibitor or ARB. This Review summarizes the present and future pharmacological manipulation of this important system.

New Approaches in the Treatment of Hypertension

Hypertension is the most common modifiable risk factor for cardiovascular disease and death, and lowering blood pressure with antihypertensive drugs reduces target organ damage and prevents cardiovascular disease outcomes. Despite a plethora of available treatment options, a substantial portion of the hypertensive population has uncontrolled blood pressure. The unmet need of controlling blood pressure in this population may be addressed, in part, by developing new drugs and devices/procedures to treat hypertension and its comorbidities. In this Compendium Review, we discuss new drugs and interventional treatments that are undergoing preclinical or clinical testing for hypertension treatment. New drug classes, eg, inhibitors of vasopeptidases, aldosterone synthase and soluble epoxide hydrolase, agonists of natriuretic peptide A and vasoactive intestinal peptide receptor 2, and a novel mineralocorticoid receptor antagonist are in phase II/III of development, while inhibitors of aminopeptidase A, dopamine β-hydroxylase, and the intestinal Na + /H + exchanger 3, agonists of components of the angiotensin-converting enzyme 2/angiotensin(1–7)/Mas receptor axis and vaccines directed toward angiotensin II and its type 1 receptor are in phase I or preclinical development. The two main interventional approaches, transcatheter renal denervation and baroreflex activation therapy, are used in clinical practice for severe treatment resistant hypertension in some countries. Renal denervation is also being evaluated for treatment of various comorbidities, eg, chronic heart failure, cardiac arrhythmias and chronic renal failure. Novel interventional approaches in early development include carotid body ablation and arteriovenous fistula placement. Importantly, none of these novel drug or device treatments has been shown to prevent cardiovascular disease outcomes or death in hypertensive patients.

Evolving role for mineralocorticoid receptor antagonists in heart failure with preserved ejection fraction

PURPOSE OF REVIEW

The majority of randomized clinical trials in heart failure with preserved ejection fraction (HFpEF) have failed to show meaningful improvements in clinical outcomes. Recent randomized trials have shown benefits from mineralocorticoid receptor antagonists (MRAs) in the management of HFpEF. This review will focus on new evidence for MRA therapy in patients with HFpEF.

RECENT FINDINGS

Three randomized trials were reviewed: the Effect of spironolactone on diastolic function and exercise capacity in patients with heart failure with preserved ejection fraction: the Aldo-DHF randomized controlled trial; the Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist trial; and its echocardiography substudy. The Aldo-DHF trial showed improvements in echocardiographic measures of diastolic function. In the Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist trial, hospitalization for heart failure was significantly reduced with MRA therapy with no difference in the primary outcome of cardiovascular death or hospitalization. In patients with high risk, however, there may be a reduction in cardiovascular mortality. We will also briefly discuss finerenone, a new generation MRA associated with a lower incidence of hyperkalemia.

SUMMARY

New evidence shows that MRA therapy decreases left ventricular mass and left atrial size, reduces hospitalization, and may reduce cardiovascular mortality in patients with high risk.

Autoradiography techniques and quantification of drug distribution

The use of radiolabeled drug compounds offers the most efficient way to quantify the amount of drug and/or drug-derived metabolites in biological samples. Autoradiography is a technique using X- ray film, phosphor imaging plates, beta imaging systems, or photo-nuclear emulsion to visualize molecules or fragments of molecules that have been radioactively labeled, and it has been used to quantify and localize drugs in tissues and cells for decades. Quantitative whole-body autoradiography or autoradioluminography (QWBA) using phosphor imaging technology has revolutionized the conduct of drug distribution studies by providing high resolution images of the spatial distribution and matching tissue concentrations of drug-related radioactivity throughout the body of laboratory animals. This provides tissue-specific pharmacokinetic (PK) compartmental analysis which has been useful in toxicology, pharmacology, and drug disposition/patterns, and to predict human exposure to drugs and metabolites, and also radioactivity, when a human radiolabeled drug study is necessary. Microautoradiography (MARG) is another autoradiographic technique that qualitatively resolves the localization of radiolabeled compounds to the cellular level in a histological preparation. There are several examples in the literature of investigators attempting to obtain drug concentration data from MARG samples; however, there are technical issues which make that problematic. These issues will be discussed. This review will present a synopsis of both techniques and examples of how they have been used for drug research in recent years.

Rationale, design, and baseline characteristics of ARTS-DN: a randomized study to assess the safety and efficacy of finerenone in patients with type 2 diabetes mellitus and a clinical diagnosis of diabetic nephropathy

BACKGROUND/AIMS

Finerenone decreases albuminuria in patients having heart failure with reduced ejection fraction and mild-to-moderate (stage 2-3) chronic kidney disease. The MinerAlocorticoid Receptor Antagonist Tolerability Study-Diabetic Nephropathy (ARTS-DN; NCT01874431) is a multicenter, randomized, double-blind, placebo-controlled, parallel-group, phase 2b study. ARTS-DN investigated whether the mineralocorticoid receptor antagonist finerenone reduces albuminuria without causing major alterations in serum potassium levels in patients with type 2 diabetes mellitus and a clinical diagnosis of DN who were receiving a renin-angiotensin-system (RAS) inhibitor.

METHODS

Patients were randomized to oral finerenone 1.25-20 mg or placebo once daily. The primary objectives were to assess the ratio of the urinary albumin-to-creatinine ratio at day 90 to that at baseline in patients receiving finerenone, and to compare it with that in the placebo group. Additional exploratory analyses included evaluating changes from baseline in serum potassium levels, efficacy and safety biomarkers, and health-related quality of life.

RESULTS

Of 1,501 patients screened, 821 (the sample population) received at least one dose of finerenone/placebo. Baseline characteristics included: male, 77.8%; white, 84.2%; very high albuminuria (formerly macroalbuminuria), 38.4%; high albuminuria (formerly microalbuminuria), 60.3%; median (range) estimated glomerular filtration rate, 66.3 (24.5-130.7) ml/min/1.73 m(2); and systolic blood pressure (mean ± standard deviation), 138.1 ± 14.4 mm Hg. There was a history of cardiovascular disease in 39.6%, diabetic neuropathy in 20.0%, and diabetic retinopathy in 19.9% of patients.

CONCLUSION

ARTS-DN is the first phase 2b trial of finerenone in combination with a RAS inhibitor in patients with type 2 diabetes mellitus and a clinical diagnosis of DN.

Diuretic response in acute heart failure-pathophysiology, evaluation, and therapy

The administration of loop diuretics to achieve decongestion is the cornerstone of therapy for acute heart failure. Unfortunately, impaired response to diuretics is common in these patients and associated with adverse outcomes. Diuretic resistance is thought to result from a complex interplay between cardiac and renal dysfunction, and specific renal adaptation and escape mechanisms, such as neurohormonal activation and the braking phenomenon. However, our understanding of diuretic response in patients with acute heart failure is still limited and a uniform definition is lacking. Three objective methods to evaluate diuretic response have been introduced, which all suggest that diuretic response should be determined based on the effect of diuretic dose administered. Several strategies have been proposed to overcome diuretic resistance, including combination therapy and ultrafiltration, but prospective studies in patients who are truly unresponsive to diuretics are lacking. An enhanced understanding of diuretic response should ultimately lead to an improved, individualized approach to treating patients with acute heart failure.

Novel effective drugs for diabetic kidney disease? or not?

INTRODUCTION

Diabetes mellitus is increasingly common worldwide and is expected to affect 592 million people by 2035. The kidney is often involved. A key goal in treating diabetes is to reduce the risk of development of kidney disease and, if kidney disease is already present, to delay the progression to end-stage renal disease (ESRD). This represents a social and ethical issue, as a significant proportion of patients reaching ESRD in developing countries do not have access to renal replacement therapy.

AREAS COVERED

The present review focuses on novel therapeutic approaches for diabetic nephropathy (DN), implemented on the basis of recent insights on its pathophysiology, which might complement the effects of single inhibition of the renin-angiotensin-aldosterone system (RAAS), the cornerstone of renoprotective interventions in diabetes, along with glycemic and blood pressure control.

EXPERT OPINION

Although a plethora of new treatment options has arisen from experimental studies, the number of novel renoprotective molecules successfully implemented in clinical practice over the last two decades is disappointingly low. Thus, new investigational strategies and diagnostic tools - including the appropriate choice of relevant renal end points and the study of urinary proteome of patients - will be as important as new therapeutic interventions to fight DN. Finally, in spite of huge financial interests in replacing the less expensive ACE inhibitors and angiotensin II receptor blockers with newer drugs, any future therapeutic approach has to be tested on top of - rather than instead of - optimal RAAS blockade.

Interfering with mineralocorticoid receptor activation: the past, present, and future

Aldosterone is a potent mineralocorticoid produced by the adrenal gland. Aldosterone binds to and activates the mineralocorticoid receptor (MR) in a plethora of tissues, but the cardiovascular actions of aldosterone are of primary interest clinically. Although MR antagonists were developed as antihypertensive agents, they are now considered to be important therapeutic options for patients with heart failure. Specifically, blocking only the MR has proven to be a difficult task because of its similarity to other steroid receptors, including the androgen and progesterone receptors. This lack of specificity caused the use of the first-generation mineralocorticoid receptor antagonists to be fraught with difficulty because of the side effects produced by drug administration. However, in recent years, several advances have been made that could potentially increase the clinical use of agents that inhibit the actions of aldosterone. These will be discussed here along with some examples of the beneficial effects of these new therapeutic agents.