Effects of serelaxin in acute heart failure patients with renal impairment: results from RELAX-AHF

Disconnect between the effects of serelaxin on renal function and outcome in acute heart failure

BACKGROUND

We aimed to study whether improvement in renal function by serelaxin in patients who were hospitalized for acute heart failure (HF) might explain any potential effect on clinical outcomes.

METHODS

We included 6318 patients from the RELAXin in AHF-2 (RELAX-AHF2) study. Improvement in renal function was defined as a decrease in serum creatinine of ≥ 0.3 mg/dL and ≥ 25%, or increase in estimated glomerular filtration rate of ≥ 25% between baseline and day 2. Worsening renal function (WRF) was defined as the reverse. We performed causal mediation analyses regarding 180-day all-cause mortality (ACM), cardiovascular death (CVD), and hospitalization for HF/renal failure.

RESULTS

Improvement in renal function was more frequently observed with serelaxin when compared with placebo [OR 1.88 (95% CI 1.64-2.15, p < 0.0001)], but was not associated with subsequent clinical outcomes. WRF occurred less frequent with serelaxin [OR 0.70 (95% CI 0.60-0.83, p < 0.0001)] and was associated with increased risk of ACM, worsening HF and the composite of CVD and HF or renal failure hospitalization. Improvement in renal function did not mediate the treatment effect of serelaxin [CVD HR 1.01 (0.99-1.04), ACM HR 1.01 (0.99-1.03), HF/renal failure hospitalization HR 0.99 (0.97-1.00)].

CONCLUSIONS

Despite the significant improvement in renal function by serelaxin in patients with acute HF, the potential beneficial treatment effect was not mediated by improvement in renal function. These data suggest that improvement in renal function might not be a suitable surrogate marker for potential treatment efficacy in future studies with novel relaxin agents in acute HF. Central illustration. Conceptual model explaining mediation analysis; treatment efficacy of heart failure therapies mediated by renal function.

Relaxin and the Cardiovascular System: from Basic Science to Clinical Practice

The peptide hormone relaxin was originally linked to reproductive physiology, where it is believed to mediate systemic and renal hemodynamic adjustments to pregnancy. Recently, its broad range of effects in the cardiovascular system has been the focus of intensive research regarding its implications under pathological conditions and potential therapeutic potential. An understanding of the multitude of cardioprotective actions prompted the study of serelaxin, recombinant human relaxin-2, for the treatment of acute heart failure. Despite early promising results from phase II studies, recently revealed RELAX-AHF-2 outcomes were rather disappointing and the treatment for acute heart failure remains an unmet medical need. This article reviews the physiologic actions of relaxin on the cardiovascular system and its relevance in the pathophysiology of cardiovascular disease. We summarize the most updated clinical data and discuss future directions of serelaxin for the treatment of acute heart failure. This should encourage additional work to determine how can relaxin's beneficial effects be exploited for the treatment of cardiovascular disease.

Pharmacological interventions for heart failure in people with chronic kidney disease

BACKGROUND

Approximately half of people with heart failure have chronic kidney disease (CKD). Pharmacological interventions for heart failure in people with CKD have the potential to reduce death (any cause) or hospitalisations for decompensated heart failure. However, these interventions are of uncertain benefit and may increase the risk of harm, such as hypotension and electrolyte abnormalities, in those with CKD.

OBJECTIVES

This review aims to look at the benefits and harms of pharmacological interventions for HF (i.e., antihypertensive agents, inotropes, and agents that may improve the heart performance indirectly) in people with HF and CKD.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies through 12 September 2019 in consultation with an Information Specialist and 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.

SELECTION CRITERIA

We included randomised controlled trials of any pharmacological intervention for acute or chronic heart failure, among people of any age with chronic kidney disease of at least three months duration.

DATA COLLECTION AND ANALYSIS

Two authors independently screened the records to identify eligible studies and extracted data on the following dichotomous outcomes: death, hospitalisations, worsening heart failure, worsening kidney function, hyperkalaemia, and hypotension. We used random effects meta-analysis to estimate treatment effects, which we expressed as a risk ratio (RR) with 95% confidence intervals (CI). We assessed the risk of bias using the Cochrane tool. We applied the GRADE methodology to rate the certainty of evidence.

MAIN RESULTS

One hundred and twelve studies met our selection criteria: 15 were studies of adults with CKD; 16 studies were conducted in the general population but provided subgroup data for people with CKD; and 81 studies included individuals with CKD, however, data for this subgroup were not provided. The risk of bias in all 112 studies was frequently high or unclear. Of the 31 studies (23,762 participants) with data on CKD patients, follow-up ranged from three months to five years, and study size ranged from 16 to 2916 participants. In total, 26 studies (19,612 participants) reported disaggregated and extractable data on at least one outcome of interest for our review and were included in our meta-analyses. In acute heart failure, the effects of adenosine A1-receptor antagonists, dopamine, nesiritide, or serelaxin on death, hospitalisations, worsening heart failure or kidney function, hyperkalaemia, hypotension or quality of life were uncertain due to sparse data or were not reported. In chronic heart failure, the effects of angiotensin-converting enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARB) (4 studies, 5003 participants: RR 0.85, 95% CI 0.70 to 1.02; I2 = 78%; low certainty evidence), aldosterone antagonists (2 studies, 34 participants: RR 0.61 95% CI 0.06 to 6.59; very low certainty evidence), and vasopressin receptor antagonists (RR 1.26, 95% CI 0.55 to 2.89; 2 studies, 1840 participants; low certainty evidence) on death (any cause) were uncertain. Treatment with beta-blockers may reduce the risk of death (any cause) (4 studies, 3136 participants: RR 0.69, 95% CI 0.60 to 0.79; I2 = 0%; moderate certainty evidence). Treatment with ACEi or ARB (2 studies, 1368 participants: RR 0.90, 95% CI 0.43 to 1.90; I2 = 97%; very low certainty evidence) had uncertain effects on hospitalisation for heart failure, as treatment estimates were consistent with either benefit or harm. Treatment with beta-blockers may decrease hospitalisation for heart failure (3 studies, 2287 participants: RR 0.67, 95% CI 0.43 to 1.05; I2 = 87%; low certainty evidence). Aldosterone antagonists may increase the risk of hyperkalaemia compared to placebo or no treatment (3 studies, 826 participants: RR 2.91, 95% CI 2.03 to 4.17; I2 = 0%; low certainty evidence). Renin inhibitors had uncertain risks of hyperkalaemia (2 studies, 142 participants: RR 0.86, 95% CI 0.49 to 1.49; I2 = 0%; very low certainty). We were unable to estimate whether treatment with sinus node inhibitors affects the risk of hyperkalaemia, as there were few studies and meta-analysis was not possible. Hyperkalaemia was not reported for the CKD subgroup in studies investigating other therapies. The effects of ACEi or ARB, or aldosterone antagonists on worsening heart failure or kidney function, hypotension, or quality of life were uncertain due to sparse data or were not reported. Effects of anti-arrhythmic agents, digoxin, phosphodiesterase inhibitors, renin inhibitors, sinus node inhibitors, vasodilators, and vasopressin receptor antagonists were very uncertain due to the paucity of studies.

AUTHORS' CONCLUSIONS

The effects of pharmacological interventions for heart failure in people with CKD are uncertain and there is insufficient evidence to inform clinical practice. Study data for treatment outcomes in patients with heart failure and CKD are sparse despite the potential impact of kidney impairment on the benefits and harms of treatment. Future research aimed at analysing existing data in general population HF studies to explore the effect in subgroups of patients with CKD, considering stage of disease, may yield valuable insights for the management of people with HF and CKD.

Effects of serelaxin in patients admitted for acute heart failure: a meta-analysis

AIMS

The effectiveness and safety of 48 h intravenous 30 μg/kg/day serelaxin infusion in acute heart failure (AHF) has been studied in six randomized, controlled clinical trials.

METHODS AND RESULTS

We conducted a fixed-effect meta-analysis including all studies of intravenous serelaxin initiated within the first 16 h of admission for AHF. Endpoints considered were the primary and secondary endpoints examined in the serelaxin phase III studies. In six randomized controlled trials, 6105 total patients were randomized to receive intravenous serelaxin 30 μg/kg/day and 5254 patients to control. Worsening heart failure to day 5 occurred in 6.0% and 8.1% of patients randomized to serelaxin and control, respectively (hazard ratio 0.77, 95% confidence interval 0.67-0.89; P = 0.0002). Serelaxin had no statistically significant effect on length of stay, or cardiovascular death, or heart or renal failure rehospitalization. Serelaxin administration resulted in statistically significant improvement in markers of renal function and reductions in both N-terminal pro-B-type natriuretic peptide and troponin. No significant adverse outcomes were noted with serelaxin. Through the last follow-up, which occurred at an average of 4.5 months (1-6 months), serelaxin administration was associated with a reduction in all-cause mortality, with an estimated hazard ratio of 0.87 (95% confidence interval 0.77-0.98; P = 0.0261).

CONCLUSIONS

Administration of intravenous serelaxin to patients admitted for AHF was associated with a highly significant reduction in the risk of 5-day worsening heart failure and in changes in renal function markers, but not length of stay, or cardiovascular death, or heart or renal failure rehospitalization. Serelaxin administration was safe and associated with a significant reduction in all-cause mortality.

[Update on heart failure]

Heart failure is one of the leading diseases in internal medicine worldwide. Because of the increase in population aging, the incidence and prevalence of heart insufficiency is rising annually and is now the most frequent individual diagnosis among hospitalized patients in Germany. The mortality rate has recently been reduced, since new pharmacological options, especially the inhibition of neprilysin, have been developed; however, heart failure is still associated with a high mortality and morbidity rate. Thus, guideline-conform treatment is of crucial importance. This review highlights and summarizes the current scientific knowledge on heart failure from 2017 and 2018 based on the guidelines of the European Society of Cardiology. New aspects about heart failure with middle grade limitations of ejection fraction are firstly presented. Subsequently, innovative diagnostic and therapeutic strategies, new pharmacological developments and handling of frequent comorbidities in patients with heart failure are discussed.

Heart Disease and Relaxin: New Actions for an Old Hormone

The hormone relaxin has long been recognized for its involvement in maternal adaptation during pregnancy. However, discoveries during the past two decades on the mechanism of action of relaxin, its family of receptors, and newly described roles in attenuating ischemia/reperfusion (I/R) injury, inflammation, and arrhythmias have prompted vast interest in exploring its therapeutic potential in cardiovascular disease. These observations inspired recently concluded clinical trials in patients with acute heart failure. This review discusses our current understanding of the protective signaling pathways elicited by relaxin in the heart, and highlights important new breakthroughs about relaxin signaling that may pave the way to more carefully designed future trials.

Newer hormonal pharmacotherapies for heart failure

INTRODUCTION

Heart failure (HF) is characterized by maladaptive neurohormonal activation of the cardiovascular and renal systems resulting in circulatory inadequacy and frequent acute exacerbations. The increasing burden of HF prompted investigation of underlying pathophysiological mechanisms and the design of pharmacotherapeutics that would target these pathways.

AREAS COVERED

A MEDLINE search for relevant original investigations and review articles of newer hormonal drugs for HF since the year 2005 till October 2017 provided us with necessary literature. Major trials and relevant clinical investigations were discussed.

EXPERT COMMENTARY

A multitude of hormonal pathways central to HF were identified, including the natriuretic peptide system and neurohormones such as relaxin, arginine vasopressin, and endothelin. However, drugs targeting these novel pathways (aliskiren, tolvaptan, ularitide, serelaxin, bosentan, macitentan) failed to show mortality benefit. This emphasizes a tremendous unmet need in the pharmacotherapy for HF, especially for the subtypes of acute HF and HF with preserved ejection fraction. Sacubitril/valsartan demonstrated substantial mortality benefit in chronic systolic HF population and is endorsed by international HF guidelines. If proven to be efficacious in larger outcome trials, finerenone can be a valuable addition baseline HF therapy. More basic, translational, and phenotype specific clinical research is warranted to improve HF pharmacotherapy.

Early treatment with tolvaptan improves diuretic response in acute heart failure with renal dysfunction

BACKGROUND

Poor response to diuretics is associated with worse prognosis in patients with acute heart failure (AHF). We hypothesized that treatment with tolvaptan improves diuretic response in patients with AHF.

METHODS

We performed a secondary analysis of the AQUAMARINE open-label randomized study in which a total of 217 AHF patients with renal impairment (eGFR < 60 mL/min/1.73 m²) were randomized to either tolvaptan or conventional treatment. We evaluated diuretic response to 40 mg furosemide or its equivalent based on two different parameters: change in body weight and net fluid loss within 48 h.

RESULTS

The mean time from patient presentation to randomization was 2.9 h. Patients with a better diuretic response showed greater relief of dyspnea and less worsening of renal function. Tolvaptan patients showed a significantly better diuretic response measured by diuretic response based both body weight [-1.16 (IQR -3.00 to -0.57) kg/40 mg vs. -0.51 (IQR -1.13 to -0.20) kg/40 mg; P < 0.001] and net fluid loss [2125.0 (IQR 1370.0-3856.3) mL/40 mg vs. 1296.3 (IQR 725.2-1726.5) mL/40 mg; P < 0.001]. Higher diastolic blood pressure and use of tolvaptan were independent predictors of a better diuretic response.

CONCLUSIONS

Better diuretic response was associated with greater dyspnea relief and less WRF. Early treatment with tolvaptan significantly improved diuretic response in AHF patients with renal dysfunction.

Serelaxin in acute heart failure patients with and without atrial fibrillation: a secondary analysis of the RELAX-AHF trial

BACKGROUND

Atrial fibrillation (AFib) is a common comorbidity in HF and affects patients' outcome. We sought to assess the effects of serelaxin in patients with and without AFib.

METHODS

In a post hoc analysis of the RELAX-AHF trial, we compared the effects of serelaxin on efficacy end points, safety end points and biomarkers in 1161 patients with and without AFib on admission electrocardiogram.

RESULTS

AFib was present in 41.3% of patients. Serelaxin had a similar effect in patients with and without AFib, including dyspnea relief by visual analog scale through day 5 [mean change in area under the curve, 541.11 (33.79, 1048.44), p = 0.0366 in AFib versus 361.80 (-63.30, 786.90), p = 0.0953 in non-AFib, interaction p = 0.5954] and all-cause death through day 180 [HR = 0.42 (0.23, 0.77), p = 0.0051 in AFib versus 0.90 (0.53, 1.52), p = 0.6888 in non-AFib, interaction p = 0.0643]. Serelaxin was similarly safe in the two groups and induced similar reductions in biomarkers of cardiac, renal and hepatic damage. Stroke occurred more frequently in AFib patients (2.8 vs. 0.8%, p = 0.0116) and there was a trend for lower stroke incidence in the serelaxin arm in AFib patients (odds ratios, 0.31, p = 0.0759 versus 3.88, p = 0.2255 in non-AFib, interaction p = 0.0518).

CONCLUSIONS

Serelaxin was similarly safe and efficacious in improving short- and long-term outcomes and inducing organ protection in acute HF patients with and without AFib.

Sex differences in early dyspnea relief between men and women hospitalized for acute heart failure: insights from the RELAX-AHF study

AIMS

Women with heart failure are typically older, and more often have hypertension and a preserved left ventricular ejection fraction as compared with men. We sought to analyze if these sex differences influence the course and outcome of acute heart failure.

METHODS AND RESULTS

We analyzed sex differences in acute heart failure in 1161 patients enrolled in the RELAX-AHF study. The pre-specified study endpoints were used. At baseline, women (436/1161 patients) were older, had a higher left ventricular ejection fraction, a higher rate of hypertension, and were treated differently from men. Early dyspnea improvement (moderate or marked dyspnea improvement measured by Likert scale during the first 24 h) was greater in women. However, dyspnea improvement over the first 5 days (change from baseline in the visual analog scale area under the curve (VAS AUC) to day 5) was similar between men and women. Women reported greater improvements in general wellbeing by Likert, but no such benefits were evident with the VAS score. Multi-variable predictors of moderate or marked dyspnea improvement were female sex (p = 0.0011), lower age (p = 0.0026) and lower diuretic dose (p = 0.0067). The additional efficacy endpoints of RELAX-AHF were similar between men and women and serelaxin was equally effective in men and women.

CONCLUSIONS

Women exhibit better earlier dyspnea relief and improvement in general wellbeing compared with men, even adjusted for age and left ventricular ejection fraction. However, in-hospital and post-discharge clinical outcomes were similar between men and women. This trial is registered at ClinicalTrials.gov, NCT00520806.