Therapeutic potential of nesiritide (recombinant b-type natriuretic peptide) in the treatment of heart failure

In vivo degradation forms, anti-degradation strategies, and clinical applications of therapeutic peptides in non-infectious chronic diseases

Current medicinal treatments for diseases comprise largely of two categories: small molecular (chemical) (e.g., aspirin) and larger molecular (peptides/proteins, e.g., insulin) drugs. Whilst both types of therapeutics can effectively treat different diseases, ranging from well-understood (in view of pathogenesis and treatment) examples (e.g., flu), to less-understood chronic diseases (e.g., diabetes), classical small molecule drugs often possess significant side-effects (a major cause of drug withdrawal from market) due to their low- or non-specific targeting. By contrast, therapeutic peptides, which comprise short sequences from naturally occurring peptides/proteins, commonly demonstrate high target specificity, well-characterized modes-of-action, and low or non-toxicity in vivo. Unfortunately, due to their small size, linear permutation, and lack of tertiary structure, peptidic drugs are easily subject to rapid degradation or loss in vivo through chemical and physical routines, thus resulting in a short half-life and reduced therapeutic efficacy, a major drawback that can reduce therapeutic efficiency. However, recent studies demonstrate that the short half-life of peptidic drugs can be significantly extended by various means, including use of enantiomeric or non-natural amino acids (AAs) (e.g., L-AAs replacement with D-AAs), chemical conjugation [e.g., with polyethylene glycol], and encapsulation (e.g., in exosomes). In this context, we provide an overview of the major in vivo degradation forms of small therapeutic peptides in the plasma and anti-degradation strategies. We also update on the progress of small peptide therapeutics that are either currently in clinical trials or are being successfully used in clinical therapies for patients with non-infectious diseases, such as diabetes, multiple sclerosis, and cancer.

Recombinant human brain natriuretic peptide ameliorates venous return function in congestive heart failure

Aims

Recombinant human brain natriuretic peptide (rh‐BNP) is commonly used as a decongestive therapy. This study aimed to investigate the instant effects of rh‐BNP on cardiac output and venous return function in post‐cardiotomy patients with congestive heart failure (CHF).

Methods and results

Twenty‐four post‐cardiotomy heart failure patients were enrolled and received a standard loading dose of rh‐BNP. Haemodynamic monitoring was performed via a pulmonary artery catheter before and after the administration of rh‐BNP. The cardiac output and venous return functions were estimated by depicting Frank‐Starling and Guyton curves. After rh‐BNP infusion, variables reflecting cardiac congestion and venous return function, such as pulmonary artery wedge pressure, mean systemic filling pressure (Pmsf) and venous return resistance index (VRRI), reduced from 15 ± 3 to 13 ± 3 mmHg, from 32 ± 7 to 28 ± 7 mmHg and from 6.7 ± 2.6 to 5.7 ± 1.8 mmHg min m²/L, respectively. Meanwhile, cardiac index, stroke volume index, and the cardiac output function curve remained unchanged per se. The decline in Pmsf [−13% (−22% to −8%)] and VRRI [−12% (−25% to −5%)] was much greater than that in the systemic vascular resistance index [−7% (−14% to 0%)]. In the subgroup analysis of reduced ejection fraction (<40%) patients, the aforementioned changes were more significant.

Conclusions

rh‐BNP might ameliorate venous return rather than cardiac output function in post‐cardiotomy CHF patients.

The Role of Neprilysin Inhibitors in the Treatment of Heart Failure with Preserved Ejection Fraction

Clinical and hemodynamic aggravation of heart failure with preserved ejection fraction (HFpEF) is largely due to progression of left ventricular (LV) diastolic dysfunction. The key role in the normal maintenance of diastolic function is played by a high level of activity of the intracellular signaling axis, cyclic guanosine-monophosphate-protein kinase G, the activity of which is significantly reduced in HFpEF. The activity of this axis can be increased by increasing the bioavailability of natriuretic peptides by blocking the enzyme neutral endopeptidase (neprilisin), which is responsible for the destruction of natriuretic peptides.This review presents experimental and clinical data on the use of neprilysin inhibitors in HFpEF and addresses prospects of this treatment.

Natriuretic peptides in therapy for decompensated heart failure

Congestive heart failure (CHF) is the most frequent cause of hospitalization for patients >65 years of age and continues to be a major public health burden among the ageing population. Unlike therapy for chronic CHF, there has been only modest progress in medical treatment for acutely decompensated CHF over the past several decades. Moreover, current treatment-consisting generally of diuretic, inotropic, and vasodilatory agents-is associated with many limitations in clinical practice. Natriuretic peptides provide a promising mechanism of action in the pathophysiologic background for CHF treatment based on their vasodilatory and diuretic properties and effective inhibition of the renin-angiotensin-aldosterone system, which is activated early in the course of CHF. Nesiritide (Natrecor® or Noratak®) is a recombinant natriuretic peptide that has the same 32 amino-acid sequence as human B-type natriuretic peptide. Nesiritide has been shown to improve dyspnea and hemodynamic parameters in patients with decompensated heart failure. Ularitide is a synthetic form of urodilatin, a natriuretic peptide hormone secreted by the kidney. Recent clinical studies suggest that ularitide may play a role in managing decompensated heart failure. This review provides an update on natriuretic peptides and their therapeutic potential in advanced CHF.

Efficacy and safety of nesiritide in patients with acute decompensated heart failure

Acute decompensated heart failure is a common clinical problem with associated poor outcomes. Over the last decade, attention to this area has greatly increased, with a focus on medical therapies that may safely offer improvement in acute symptoms and early outcomes. Previous therapies that focused on increased inotropy have generally failed to improve symptoms without adverse consequences. Thus, attention towards vasodilators and natriuretic peptides, such as nesiritide, has increased owing to nesiritide's symptomatic improvement and unique mechanism of improvement in hemodynamics. However, the pathophysiology of acute decompensated heart failure is complex and the impact of nesiritide on important clinical end points, beyond symptomatic and hemodynamic improvement, is unknown.

A sandwich ELISA for assessment of pharmacokinetics of HSA-(BNP)2 fusion protein in mouse plasma

Brain natriuretic peptide (BNP) is a circulating hormone of cardiac origin that plays an important role in the regulation of intravascular blood volume and vascular tone. HSA-(BNP)(2), derived from the joining of human BNP to the C-terminus of human serum albumin (HSA), has been developed to prolong the BNP pharmacodynamic action. For the analysis of pharmacokinetics of the new drug, a novel sandwich enzyme-linked immunosorbent assay (ELISA) was established and validated to quantify HSA-(BNP)(2) fusion protein in mouse plasma. The ELISA method was calibrated with 1:10 and 1:100 dilutions of blank mouse plasma spiked with HSA-(BNP)(2) standard and validated with respect to parallelism, precision (intra- and inter-assay variation), accuracy (recovery), specificity and stability. The practical working range was estimated to be 31.2-2000ng/ml with the limit of detection was 7.8ng/ml. Recoveries ranged from 80.5 to 108.4%, while the intra- and inter-assay precisions were <2.73% and <4.32%, respectively. The terminal half-life of HSA-(BNP)(2) was 2.14h, which had extended more than 40 times compared to 3.1min half-life of BNP monomer in mouse.

Benefit-Risk Assessment of Nesiritide in the Treatment of Acute Decompensated Heart Failure

Nesiritide is a recombinant form of human B-type natriuretic peptide, a naturally occurring endogenous hormone released by cardiac ventricles in response to an increase in ventricular wall stress. Its use in the treatment of acute decompensated heart failure (ADHF) has been evaluated in a series of randomised controlled clinical trials. It is currently approved in the US for the treatment of ADHF. Nesiritide induces a balanced vasodilation and an indirect increase in cardiac output, but has no actual inotropic effects and exerts a neutral effect on heart rate. In addition, it inhibits adverse neurohormonal activation and, in some individuals, promotes natriuresis and diuresis. In adults with ADHF, nesiritide reduces pulmonary capillary wedge pressure, right atrial pressure and systemic vascular resistance; decreases symptoms of heart failure; and enhances global clinical status. Important questions regarding the risks of nesiritide therapy have recently been raised, and resolution of the safety of nesiritide is a process that remains in evolution. The most frequently reported adverse effect is dose-related hypotension. In addition, nesiritide may cause an acute increase in serum creatinine concentration. This increase seems to be a haemodynamic response to a combination of volume depletion, vasodilation and neurohormonal inhibition. Nesiritide-induced changes in renal function have not been definitively shown to negatively affect mortality. The effect of nesiritide on all-cause mortality is currently unresolved. Recent meta-analyses of existing databases have raised concerns regarding adverse effects of the drug on 30-day mortality. However, reviews of large, observational, registry databases do not suggest an adverse inpatient mortality effect compared with other vasodilator therapies. Further resolution of the mortality question awaits completion of pending randomised controlled clinical trials. When used for approved indications and according to recommended dosage and administration regimens, nesiritide represents a reasonable treatment adjunct for ADHF.

Nesiritide for the treatment of congestive heart failure

Nesiritide (Natrecor) is a recombinant form of the human B-type natriuretic peptide (BNP) that has been shown, through several studies, to have beneficial natriuretic, diuretic and vasodilatory effects in the treatment of congestive heart failure (CHF). Nesiritide mimics the actions of endogenous BNP by binding to and stimulating receptors in the heart, kidney and vasculature. Nesiritide functions as both a potent venous and arterial vasodilator and has been shown to improve cardiac haemodynamics more rapidly and to a greater extent than intravenous nitroglycerin, as well as having fewer side effects. When compared in an open-label trial, nesiritide has also been shown to be less proarrhythmic than dobutamine. The major adverse effect of nesiritide, as with other vasodilators, is symptomatic hypotension, which occurred infrequently in clinical trials. Overall, nesiritide represents an effective and safe therapeutic option for the treatment of decompensated CHF.

Drug treatment of patients with decompensated heart failure

Decompensated heart failure (HF) may be defined as sustained deterioration of at least one New York Heart Association functional class, usually with evidence of sodium retention. Episodes of decompensation are most commonly precipitated by sodium retention, often associated with medication noncompliance. Our therapeutic approach to hospitalized patients is based on the documented hemodynamic responses to vasodilator therapy, with redistribution of mitral regurgitant flow to forward cardiac output and decompression of the left atrium. Invasive hemodynamic monitoring is seldom required for the effective management of patients with HF and there are risks associated with pulmonary artery catheterization. The currently available parenteral vasoactive drugs for decompensated heart failure include: (i) vasodilators such as nesiritide, nitroprusside and nitroglycerin (glyceryl trinitrate); (ii) catecholamine inotropes, primarily dobutamine; and (iii) inodilators such as milrinone, a phosphodiesterase inhibitor. Vasodilators are most appropriate for those patients who are primarily volume-overloaded, but with adequate peripheral perfusion. In this class of agents, nesiritide (recombinant human B-type natriuretic peptide) offers advantages over currently available drugs. Nesiritide produces rapid and sustained decreases in right atrial and pulmonary capillary wedge pressures, with reduction in pulmonary and systemic vascular resistance and increases in cardiac index. The hemodynamic effects of nesiritide infusion were sustained over a duration of 1 week and the drug may be used without intensive monitoring in patients with decompensated HF. Treatment with dobutamine is indicated in patients in whom low cardiac output rather than elevated pulmonary pressure is the primary hemodynamic aberration. However, milrinone reduces left atrial congestion more effectively than dobutamine, and is well tolerated and effective when used in patients receiving beta-blockers. In-patient therapy for decompensated HF is a short term exercise for symptom relief and provides an opportunity to re-assess management in the continuum of care.