The efficacy and safety of lixivaptan in outpatients with heart failure and volume overload: results of a multicentre, randomized, double-blind, placebo-controlled, parallel-group study

Risks of vaptans in hypernatremia and serum sodium overcorrection: A systematic review and meta-analysis of randomised controlled trials

OBJECTIVE

Serum sodium overcorrection and hypernatremia are significant health risks. We conducted a systematic review and meta-analysis to evaluate the risks of vaptans in hypernatremia and serum sodium overcorrection.

METHODS

We searched PubMed, Embase, and CENTRAL for randomised controlled trials. We included studies comparing vaptans and placebo with data on hypernatremia and serum sodium overcorrection. The study quality was assessed using the Cochrane Collaboration's risk-of-bias assessment tool. Fixed-effect model meta-analysis was used to pool the data. Different analyses were performed to ensure the accuracy of the results.

RESULTS

Twenty-eight studies were included in the meta-analysis of hypernatremia incidence. Treatment with vaptans resulted in a higher risk of hypernatremia than placebo (3.8% vs 1.0%, odds ratio [OR] 2.69; 95% confidence interval [CI] 1.97-3.68). The subgroup with baseline hyponatremia had a lower risk of hypernatremia incidence; however, the use of loop diuretics increased the risk. Fourteen studies were included in the analysis of the incidence of serum sodium overcorrection. A higher risk of serum sodium overcorrection was found in using vaptans vs placebo (4.4% vs 1.4%; OR 2.26; 95% CI 1.32-3.86).

CONCLUSION

Vaptans showed higher risks in the incidence of hypernatremia and serum sodium overcorrection than placebo. In addition, combination with loop diuretics increased the risk of hypernatremia. The risk of serum sodium overcorrection should be concerned in patients with hyponatremia and normal serum sodium equally. Using a low dose of vaptans can reduce both risks.

The New Biology of Diabetic Kidney Disease-Mechanisms and Therapeutic Implications

Diabetic kidney disease remains the most common cause of end-stage kidney disease in the world. Despite reductions in incidence rates of myocardial infarction and stroke in people with diabetes over the past 3 decades, the risk of diabetic kidney disease has remained unchanged, and may even be increasing in younger individuals afflicted with this disease. Accordingly, changes in public health policy have to be implemented to address the root causes of diabetic kidney disease, including the rise of obesity and diabetes, in addition to the use of safe and effective pharmacological agents to prevent cardiorenal complications in people with diabetes. The aim of this article is to review the mechanisms of pathogenesis and therapies that are either in clinical practice or that are emerging in clinical development programs for potential use to treat diabetic kidney disease.

Comparison of the Hepatotoxic Potential of Two Treatments for Autosomal-Dominant Polycystic Kidney DiseaseUsing Quantitative Systems Toxicology Modeling

Purpose

Autosomal-dominant polycystic kidney disease (ADPKD) is an orphan disease with few current treatment options. The vasopressin V₂ receptor antagonist tolvaptan is approved in multiple countries for the treatment of ADPKD, however its use is associated with clinically significant drug-induced liver injury.

Methods

In prior studies, the potential for hepatotoxicity of tolvaptan was correctly predicted using DILIsym®, a quantitative systems toxicology (QST) mathematical model of drug-induced liver injury. In the current study, we evaluated lixivaptan, another proposed ADPKD treatment and vasopressin V₂ receptor antagonist, using DILIsym®. Simulations were conducted that assessed the potential for lixivaptan and its three main metabolites to cause hepatotoxicity due to three injury mechanisms: bile acid accumulation, mitochondrial dysfunction, and oxidative stress generation. Results of these simulations were compared to previously published DILIsym results for tolvaptan.

Results

No ALT elevations were predicted to occur at the proposed clinical dose for lixivaptan, in contrast to previously published simulation results for tolvaptan. As such, lixivaptan was predicted to have a markedly lower risk of hepatotoxicity compared to tolvaptan with respect to the hepatotoxicity mechanisms represented in DILIsym.

Conclusions

These results demonstrate the potential for using QST methods to differentiate drugs in the same class for their potential to cause hepatotoxicity.

Electronic supplementary material

The online version of this article (10.1007/s11095-019-2726-0) contains supplementary material, which is available to authorized users.

Interventions for chronic non-hypovolaemic hypotonic hyponatraemia

BACKGROUND

Chronic (present > 48 hours) non-hypovolaemic hyponatraemia occurs frequently, can be caused by various conditions, and is associated with shorter survival and longer hospital stays. Many treatments, such as fluid restriction or vasopressin receptor antagonists can be used to improve the hyponatraemia, but whether that translates into improved patient-important outcomes is less certain.

OBJECTIVES

This review aimed to 1) look at the benefits and harms of interventions for chronic non-hypovolaemic hypotonic hyponatraemia when compared with placebo, no treatment or head-to-head; and 2) determine if benefits and harms vary in absolute or relative terms dependent on the specific compound within a drug class, on the dosage used, or the underlying disorder causing the hyponatraemia.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 1 December 2017 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov. We also screened the reference lists of potentially relevant studies, contacted authors, and screened the websites of regulatory agencies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs that compared the effects of any intervention with placebo, no treatment, standard care, or any other intervention in patients with chronic non-hypovolaemic hypotonic hyponatraemia. We also included subgroups with hyponatraemia from studies with broader inclusion criteria (e.g. people with chronic heart failure or people with cirrhosis with or without hyponatraemia), provided we could obtain outcomes for participants with hyponatraemia from the report or the study authors.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed risk of bias. We expressed treatment effects as mean difference (MD) for continuous outcomes (health-related quality of life, length of hospital stay, change from baseline in serum sodium concentration, cognitive function), and risk ratio (RR) for dichotomous outcomes (death, response and rapid increase in serum sodium concentration, hypernatraemia, polyuria, hypotension, acute kidney injury, liver function abnormalities) together with 95% confidence intervals (CI).

MAIN RESULTS

We identified 35 studies, enrolling 3429 participants. Twenty-eight studies (3189 participants) compared a vasopressin receptor antagonist versus placebo, usual care, no treatment, or fluid restriction. In adults with chronic, non-hypovolaemic hypotonic hyponatraemia, vasopressin receptor antagonists have uncertain effects on death at six months (15 studies, 2330 participants: RR 1.11, 95% CI 0.92 to 1.33) due to risk of selective reporting and serious imprecision; and on health-related quality of life because results are at serious risk of performance, selective reporting and attrition bias, and suffer from indirectness related to the validity of the Short Form Health Survey (SF-12) in the setting of hyponatraemia. Vasopressin receptor antagonists may reduce hospital stay (low certainty evidence due to risk of performance bias and imprecision) (3 studies, 610 participants: MD -1.63 days, 95% CI -2.96 to -0.30), and may make little or no difference to cognitive function (low certainty evidence due to indirectness and imprecision). Vasopressin receptor antagonists probably increase the intermediate outcome of serum sodium concentration (21 studies, 2641 participants: MD 4.17 mmol/L, 95% CI 3.18 to 5.16), corresponding to two and a half as many people having a 5 to 6 mmol/L increase in sodium concentration compared with placebo at 4 to 180 days (moderate certainty evidence due to risk of attrition bias) (18 studies, 2014 participants: RR 2.49, 95% CI 1.95 to 3.18). But they probably also increase the risk of rapid serum sodium correction - most commonly defined as > 12 mmol/L/d (moderate certainty evidence due to indirectness) (14 studies, 2058 participants: RR 1.67, 95% CI 1.16 to 2.40) and commonly cause side-effects such as thirst (13 studies, 1666 participants: OR 2.77, 95% CI 1.80 to 4.27) and polyuria (6 studies, 1272 participants): RR 4.69, 95% CI 1.59 to 13.85) (high certainty evidence). The potential for liver toxicity remains uncertain due to large imprecision. Effects were generally consistent across the different agents, suggesting class effect.Data for other interventions such as fluid restriction, urea, mannitol, loop diuretics, corticosteroids, demeclocycline, lithium and phenytoin were largely absent.

AUTHORS' CONCLUSIONS

In people with chronic hyponatraemia, vasopressin receptor antagonists modestly raise serum sodium concentration at the cost of a 3% increased risk of it being rapid. To date there is very low certainty evidence for patient-important outcomes; the effects on mortality and health-related quality of life are unclear and do not rule out appreciable benefit or harm; there does not appear to be an important effect on cognitive function, but hospital stay may be slightly shorter, although available data are limited. Treatment decisions must weigh the value of an increase in serum sodium concentration against its short-term risks and unknown effects on patient-important outcomes. Evidence for other treatments is largely absent.Further studies assessing standard treatments such as fluid restriction or urea against placebo and one-another would inform practice and are warranted. Given the limited available evidence for patient-important outcomes, any study should include these outcomes in a standardised manner.

Vasopressin and Vasopressin Antagonists in Heart Failure

Despite the introduction of multiple new pharmacological agents over the past three decades in the field of heart failure (HF), overall prognosis remains poor. Hyponatremia is prevalent in HF patients and has been suggested as a contributor to poor response to standard therapy. Elevated levels of arginine vasopressin (AVP), a peptide hormone produced in the hypothalamus, play a role in development of hyponatremia, and AVP and its surrogate, copeptin, are related to changes in osmolality, hemodynamics, neuro-hormones as well as in overall outcome in HF patients. Of current pharmacological interest are the selective and non-selective vasopressin receptor antagonists (VRAs), which inhibit vasoconstriction and cardiac remodeling mediated by the V_1a receptors in smooth blood vessels, and water retention (increased urine osmolality and decreased water excretion) by increasing aquaporin-2 water channels mediated by the V₂ receptors in the renal collecting tubules. The optimal use of VRAs is yet to be determined, especially in patients with congestive HF. Although long-term effects on improvement in mortality have not been shown in the Efficacy of Vasopressin Antagonism in Heart Failure Outcome Study with Tolvaptan (EVEREST) trial, the only long-term outcome trial to date, many short-term studies indicate beneficial aquaretic- and hemodynamic-effects of the VRAs. In contrast to loop diuretics, these new agents tend to increase urine flow and the excretion of electrolyte-free water (so-called aquaresis) in patients with HF, without substantial changes in sodium or potassium excretion. This chapter reviews the role of AVP and copeptin in HF, and the treatment potential of VRAs in HF.

Vasopressin receptor antagonists for the treatment of heart failure: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND/OBJECTIVES

Elevated vasopressin may increase systemic vascular resistance and pulmonary capillary wedge pressure, subsequently decrease stroke volume and cardiac output. Vasopressin receptor antagonists may counteract these effects and improve outcomes in heart failure. We aimed to assess benefits and harms of vasopressin receptor antagonists (VRAs) versus placebo in addition to standard care in adults with heart failure (HF).

METHODS

We conducted a systematic review of randomized controlled trials with searches of CENTRAL and MEDLINE to January 2014 and reference lists without language restriction. Meta-analysis using a random-effects model was done for all-cause and cardiovascular mortality, hospitalization for heart failure, changes in clinical assessment of HF, serum sodium concentration (Na), kidney function and treatment-specific side effects.

RESULTS

We identified 13 trials and 5,525 participants. In 10 trials, participants received standard therapy for HF. In low-quality evidence, VRAs in patients with HF had no effect on all-cause mortality risk ratios (RR 0.98; CI 0.88-1.08), cardiovascular mortality (RR 1.03; CI 0.91-1.16) or change in creatinine mean difference (MD -0.01; CI -0.10 to 0.09 mg/dL), but reduced body weight by 0.8 kg from baseline (MD -0.83; CI -1.10 to -0.55 kg) and increased Na (MD 2.61; 95 % CI 1.88-3.35 mmol/L). Compared with placebo, VRAs increased the risk of adverse events by 14 % (RR 1.14; CI 1.04-1.26). Studies were generally limited to short-term follow-up with limited data available on patient important outcomes.

CONCLUSIONS

Vasopressin receptors antagonists may reduce body weight and increase Na but do not improve all-cause mortality, cardiovascular mortality or kidney function. In addition, acceptability of long-term treatment side effects and hospitalization appears problematic.

Correlation between changes in bodyweight and changes in ascites volume in liver cirrhosis patients with hepatic edema in short-term diuretic therapy

AIM

Although it is an important treatment challenge to treat ascites with diuretic therapy, no objective markers have been established to assess improvement of ascites. However, change in bodyweight has been used as a marker of change in ascites volume. Thus, we evaluated the relationship between changes in bodyweight and changes in ascites volume in liver cirrhosis patients with ascites.

METHODS

We calculated ascites volume in patients using the simple 5-point method by conventional computed tomography and conducted a correlation analysis between changes in bodyweight and changes in ascites volume as a part of our double-blind phase 3 trial of tolvaptan.

RESULT

Change in bodyweight (x-axis) was correlated with change in ascites volume (y-axis) in all included patients (r = 0.52). A strong correlation were observed between the changes in patients without lower limb edema (r = 0.61). These correlations between the changes were expressed by the following linear regression equations: y = -0.102 + 0.206x or y = -0.033 + 0.292x, respectively. Proportions of change in ascites volume to change in bodyweight were estimated to be nearly 30%. Therefore, bodyweight reduction was confirmed to lead to improvement in ascites.

CONCLUSION

Change in bodyweight can be an objective marker to assess improvement of hepatic edema in the short-term diuretic therapy in everyday clinical practice. Decrease in ascites volume was estimated to account for nearly 30% of bodyweight reduction.

Synthesis and biological evaluation of substituted desloratadines as potent arginine vasopressin V2 receptor antagonists

Twenty-one non-peptide substituted desloratadine class compounds were synthesized as novel arginine vasopressin receptor antagonists from desloratadine via successive acylation, reduction and acylation reactions. Their structures were characterized by ¹H-NMR and HRMS, their biological activity was evaluated by in vitro and in vivo studies. The in vitro binding assay and cAMP accumulation assay indicated that these compounds are potent selective V2 receptor antagonists. Among them compounds 1n, 1t and 1v exhibited both high affinity and promising selectivity for V2 receptors. The in vivo diuretic assay demonstrated that 1t presented remarkable diuretic activity. In conclusion, 1t is a potent novel AVP V2 receptor antagonist candidate.

Diagnosis, evaluation, and treatment of hyponatremia: expert panel recommendations

Hyponatremia is a serious, but often overlooked, electrolyte imbalance that has been independently associated with a wide range of deleterious changes involving many different body systems. Untreated acute hyponatremia can cause substantial morbidity and mortality as a result of osmotically induced cerebral edema, and excessively rapid correction of chronic hyponatremia can cause severe neurologic impairment and death as a result of osmotic demyelination. The diverse etiologies and comorbidities associated with hyponatremia pose substantial challenges in managing this disorder. In 2007, a panel of experts in hyponatremia convened to develop the Hyponatremia Treatment Guidelines 2007: Expert Panel Recommendations that defined strategies for clinicians caring for patients with hyponatremia. In the 6 years since the publication of that document, the field has seen several notable developments, including new evidence on morbidities and complications associated with hyponatremia, the importance of treating mild to moderate hyponatremia, and the efficacy and safety of vasopressin receptor antagonist therapy for hyponatremic patients. Therefore, additional guidance was deemed necessary and a panel of hyponatremia experts (which included all of the original panel members) was convened to update the previous recommendations for optimal current management of this disorder. The updated expert panel recommendations in this document represent recommended approaches for multiple etiologies of hyponatremia that are based on both consensus opinions of experts in hyponatremia and the most recent published data in this field.

Hyponatremia in patients with heart failure

The present review analyses the mechanisms relating heart failure and hyponatremia, describes the association of hyponatremia with the progress of disease and morbidity/mortality in heart failure patients and presents treatment options focusing on the role of arginine vasopressin (AVP)-receptor antagonists. Hyponatremia is the most common electrolyte disorder in the clinical setting and in hospitalized patients. Patients with hyponatremia may have neurologic symptoms since low sodium concentration produces brain edema, but the rapid correction of hyponatremia is also associated with major neurologic complications. Patients with heart failure often develop hyponatremia owing to the activation of many neurohormonal systems leading to decrease of sodium levels. A large number of clinical studies have associated hyponatremia with increased morbidity and mortality in patients hospitalized for heart failure or outpatients with chronic heart failure. Treatment options for hyponatremia in heart failure, such as water restriction or the use of hypertonic saline with loop diuretics, have limited efficacy. AVP-receptor antagonists increase sodium levels effectively and their use seems promising in patients with hyponatremia. However, the effects of AVP-receptor antagonists on hard outcomes in patients with heart failure and hyponatremia have not been thoroughly examined.

Cognitive change in heart failure: a systematic review

BACKGROUND

Cognitive impairment, highly prevalent in patients with heart failure (HF), increases risk for hospitalization and mortality. However, the course of cognitive change in HF is not well characterized. The purpose of this systematic review was to examine the available evidence longitudinal changes in cognitive function in patients with HF.

METHODS AND RESULTS

A literature search of several electronic databases was performed. Studies published from January 1, 1980, to September 30, 2012, that used validated measures to diagnose HF and assess cognitive function ≥2× in adults with HF were eligible for inclusion. Change in cognitive function was examined in the context of HF treatments applied (eg, medication initiation, left ventricular assist device implantation), length of follow-up, and comparison group. Fifteen studies met eligibility criteria. Significant decline in cognitive function was noted among patients with HF followed up for >1 year. Improvements in cognition were observed among patients with HF undergoing interventions to improve cardiac function (eg, heart transplantation) and among patients examined over short time periods (<1 year). Studies comparing patients' cognition over time with their own baseline tended to report improvements, whereas studies using a comparison group without HF tended to report declines or stability in cognition over time among patients with HF.

CONCLUSIONS

Patients with HF are at increased risk for cognitive decline, but this risk seems to be modifiable with cardiac treatment. Further research is needed to identify the mechanisms that cause cognitive changes in HF.

Evaluation of lixivaptan in euvolemic and hypervolemic hyponatremia and heart failure treatment

INTRODUCTION

Lixivaptan is a selective vasopressin type 2 (V2) receptor antagonist that induces aquaresis, the electrolytes sparing excretion of water. Its ability to correct hyponatremia has been demonstrated in experimental animal studies as well as in clinical trials in humans. Recently, three Phase III, double-blind, randomized, placebo-controlled studies have been completed. In two studies, patients with euvolemic hyponatremia were enrolled, one in the inpatient and the other in the outpatient setting and the third study involved patients with hypervolemic hyponatremia hospitalized for decompensated heart failure (HF). The trials confirmed the efficacy of lixivaptan in raising serum sodium but raised concern about its safety in patients hospitalized with decompensated HF.

AREAS COVERED

The authors review original publications on lixivaptan and summarize their findings. Specifically, the authors present information regarding its structure, pharmacodynamics and kinetics, metabolism as well as its efficacy and safety in laboratory animals and human studies. Furthermore, the FDA website was accessed to obtain information presented at the September 13, 2012 meeting of the Cardiovascular and Renal Drugs Advisory Committee.

EXPERT OPINION

The published data indicate that lixivaptan raises sodium levels in hyponatremic patients and supports its use in patients with euvolemic hyponatremia. However, the authors note that more safety data are still needed specifically in patients with decompensated HF.