Natriuretic Peptide-Based Inclusion Criteria in a Heart Failure Clinical Trial: Insights From COMMANDER HF

OBJECTIVES

This study investigated the effects of a mid-trial protocol amendment requiring elevated natriuretic peptides for inclusion in the COMMANDER-HF (A Study to Assess the Effectiveness and Safety of Rivaroxaban in Reducing the Risk of Death, Myocardial Infarction, or Stroke in Participants with Heart Failure and Coronary Artery Disease Following an Episode of Decompensated Heart Failure) trial.

BACKGROUND

Heart failure (HF) trials that select patients based on history of HF hospitalization alone are susceptible to regional variations in event rates. Elevated plasma concentrations of natriuretic peptides (NPs) as selection criteria may help HF ascertainment and risk enrichment. In the COMMANDER-HF trial, B-type natriuretic peptide ≥200 ng/l or N-terminal pro-B-type natriuretic peptide ≥800 ng/l were added to inclusion criteria as a mid-trial protocol amendment, providing a unique case-study of NP-based inclusion criteria.

METHODS

We compared the baseline characteristics, event rates, and treatment effects for patients enrolled before and after the NP protocol amendment. The primary endpoint was all-cause death, myocardial infarction, or stroke. Secondary endpoints included HF rehospitalization and cardiovascular death.

RESULTS

A total of 5,022 patients with left ventricular ejection fraction ≤40% and coronary artery disease were included. Compared to patients enrolled before the NP protocol amendment, those enrolled post-amendment (n = 3,867, 77%) were older, more often had diabetes, and had lower values for body mass index, left ventricular ejection fraction, and estimated glomerular filtration rate, higher heart rate, and higher event rates: primary endpoint (hazard ratio [HR]: 1.32; 95% confidence interval [CI]: 1.16 to 1.50), cardiovascular death (HR: 1.29; 95% CI: 1.11 to 1.50), HF rehospitalization (HR: 1.31; 95% CI: 1.15 to 1.49), and major bleeding (HR: 1.71; 95% CI: 1.11 to 2.65). Differences between pre- and post-amendment rates were confined to and driven by Eastern Europe. This protocol amendment did not modify the neutral effect of rivaroxaban on the primary endpoint (p interaction = 0.36) or secondary endpoints.

CONCLUSIONS

In a global event-driven trial of rivaroxaban in HF, requiring elevated NPs for inclusion increased event rates allowing earlier completion of the trial but did not modify treatment effect. These data inform future HF trials regarding the expected impact of NP-based inclusion criteria on patient characteristics and event rates. (COMMANDER HF [A Study to Assess the Effectiveness and Safety of Rivaroxaban in Reducing the Risk of Death, Myocardial Infarction, or Stroke in Participants With Heart Failure and Coronary Artery Disease Following an Episode of Decompensated Heart Failure] NCT01877915).

Effects of Elamipretide on Left Ventricular Function in Patients With Heart Failure With Reduced Ejection Fraction: The PROGRESS-HF Phase 2 Trial

BACKGROUND

Elamipretide, a novel mitochondrial modulating agent, improves myocardial energetics; however, it is unknown whether this mechanistic benefit translates into improved cardiac structure and function in heart failure (HF) with reduced ejection fraction (HFrEF). The objective of this study was to evaluate the effects of multiple subcutaneous doses of elamipretide on left ventricular end systolic volume (LVESV) as assessed by cardiac magnetic resonance imaging.

METHODS

We randomized 71 patients with HFrEF (LVEF ≤ 40%) in a double-blind, placebo-controlled trial in a 1:1:1 ratio to receive placebo, 4 mg or 40 mg elamipretide once daily for 28 consecutive days.

RESULTS

The mean age (standard deviation) of the study population was 65 ± 10 years, 24% were females, and the mean EF was 31% ± 7%. The change in LVESV from baseline to week 4 was not significantly different between elamipretide 4 mg (89.4 mL to 85 mL; difference, -4.4 mL) or 40 mg (77.9 mL to 76.6 mL; difference, -1.2 mL) compared with placebo (77.7 mL to 74.6 mL; difference, -3.8 mL) (4 mg vs placebo: difference of means, -0.3; 95% CI, -4.6 to 4.0; P  =  0.90; and 40 mg vs placebo: difference of means, 2.3; 95% CI, -1.9 to 6.5; P  =  0.28). Also, no significant differences in change in LVESV and LVEF were observed between placebo and either of the elamipretide groups. Rates of any study drug-related adverse events were similar in the 3 groups.

CONCLUSIONS

Elamipretide was well tolerated but did not improve LVESV at 4 weeks in patients with stable HFrEF compared with placebo.

Preoperative Noncoronary Cardiovascular Assessment and Management of Kidney Transplant Candidates

The pretransplant risk assessment for patients with ESKD who are undergoing evaluation for kidney transplant is complex and multifaceted. When considering cardiovascular disease in particular, many factors should be considered. Given the increasing incidence of kidney transplantation and the growing body of evidence addressing ESKD-specific cardiovascular risk profiles, there is an important need for a consolidated, evidence-based model that considers the unique cardiovascular challenges that these patients face. Cardiovascular physiology is altered in these patients by abrupt shifts in volume status, altered calcium-phosphate metabolism, high-output states (in the setting of arteriovenous fistulization), and adverse geometric and electrical remodeling, to name a few. Here, we present a contemporary review by addressing cardiomyopathy/heart failure, pulmonary hypertension, valvular dysfunction, and arrhythmia/sudden cardiac death within the ESKD population.

Temporal Relation Between Myocardial Fibrosis and Heart Failure With Preserved Ejection Fraction: Association With Baseline Disease Severity and Subsequent Outcome

Importance

Among myriad changes occurring during the evolution of heart failure with preserved ejection fraction (HFpEF), cardiomyocyte-extracellular matrix interactions from excess collagen may affect microvascular, mechanical, and electrical function.

Objective

To investigate whether myocardial fibrosis (MF) is similarly prevalent both in those with HFpEF and those at risk for HFpEF, similarly associating with disease severity and outcomes.

Design, Setting, and Participants

Observational cohort study from June 1, 2010, to September 17, 2015, with follow-up until December 14, 2015, at a cardiovascular magnetic resonance (CMR) center serving an integrated health system. Consecutive patients with preserved systolic function referred for CMR were eligible. Cardiovascular magnetic resonance was used to exclude patients with cardiac amyloidosis (n = 19).

Exposures

Myocardial fibrosis quantified by extracellular volume (ECV) CMR measures.

Main Outcome and Measures

Baseline BNP; subsequent hospitalization for heart failure or death.

Results

Of 1174 patients identified (537 [46%] female; median [interquartile range {IQR}] age, 56 [44-66] years), 250 were "at risk" for HFpEF given elevated brain-type natriuretic peptide (BNP) level; 160 had HFpEF by documented clinical diagnosis, and 745 did not have HFpEF. Patients either at risk for HFpEF or with HFpEF demonstrated similarly higher prevalence/extent of MF and worse prognosis compared with patients with no HFpEF. Among those at risk for HFpEF or with HFpEF, the actual diagnosis of HFpEF was not associated with significant differences in MF (median ECV, 28.2%; IQR, 26.2%-30.7% vs 28.3%; IQR, 25.5%-31.4%; P = .60) or prognosis (log-rank 0.8; P = .38). Over a median of 1.9 years, 61 patients at risk for HFpEF or with HFpEF experienced adverse events (19 hospitalization for heart failure, 48 deaths, 6 with both). In those with HFpEF, ECV was associated with baseline log BNP (disease severity surrogate) in multivariable linear regression models, and was associated with outcomes in multivariable Cox regression models (eg, hazard ratio 1.75 per 5% increase in ECV, 95% CI, 1.25-2.45; P = .001 in stepwise model) whether grouped with patients at risk for HFpEF or not.

Conclusions and Relevance

Among myriad changes occurring during the apparent evolution of HFpEF where elevated BNP is prevalent, MF was similarly prevalent in those with or at risk for HFpEF. Conceivably, MF might precede clinical HFpEF diagnosis. Regardless, MF was associated with disease severity (ie, BNP) and outcomes. Whether cells and secretomes mediating MF represent therapeutic targets in HFpEF warrants further evaluation.

Expanded algorithm for managing patients with acute decompensated heart failure

Heart failure is a complex disease process, the manifestation of various cardiac and noncardiac abnormalities. General treatment approaches for heart failure have remained the same over the past decades despite the advent of novel therapies and monitoring modalities. In the same vein, the readmission rates for heart failure patients remain high and portend a poor prognosis for morbidity and mortality. In this context, development and implementation of improved algorithms for assessing and treating HF patients during hospitalization remains an unmet need. We propose an expanded algorithm for both monitoring and treating patients admitted for acute decompensated heart failure with the goal to improve post-discharge outcomes and decrease rates of rehospitalizations.

A new educational program in heart failure drug development: the Brescia international master program

: Despite recent advances in chronic heart failure treatment, prognosis of acute heart failure patients remains poor with a heart failure rehospitalization rate or death reaching approximately 25% during the first 6 months after discharge. In addition, about half of these patients have preserved ejection fraction for which there are no evidence-based therapies. Disappointing results from heart failure clinical trials over the past 20 years emphasize the need for developing novel approaches and pathways for testing new heart failure drugs and devices. Indeed, many trials are being conducted without matching the mechanism and action of the drug with the clinical event. The implementation of these novel approaches should be coupled with the training of a new generation of heart failure physicians and scientists in the art and science of clinical trials. Currently, drug development is led by opinion leaders and experts who, despite their huge personal experience, were never trained systematically on drug development. The aim of this article is to propose a training program of 'drug development in Heart Failure'. A physician attending this course would have to be trained with a major emphasis on heart failure pathophysiology to better match mechanisms of death and rehospitalization with mechanism of action of the drug. Applicants will have to prove their qualifications and special interest in heart failure drug development before enrollment. This article should serve as a roadmap on how to apply emerging general principles in an innovative drug-development-in-heart-failure-process as well as the introduction of a new educational and mentorship program focusing on younger generations of researchers.

Medication dosing for heart failure with reduced ejection fraction - opportunities and challenges

Multiple drug classes have shown incremental benefits in heart failure with reduced ejection fraction. Most of these trials were designed to achieve specific doses of the investigational agent. Clinical practice guidelines recommend using the same target dosing of therapies, as tolerated. However, with the increasing number of available therapies, clinicians face the challenge of simultaneously using several drugs, achieving target doses, and managing side effects that are often overlapping. Blood pressure, renal function, hyperkalaemia, and other factors may impede achieving target doses of all medications, leaving clinicians with dilemmas as to how to sequence and dose these various classes of drugs. The guideline-directed eligibility for certain drugs and devices requires stability on maximally tolerated doses of background therapies. However, significant variability exists in dosing achieved in clinical practice. We discuss the existing background data regarding the doses of heart failure medications in clinical trials and in practice, and provide recommendations on how to navigate this complex therapeutic decision-making.

Safety and Tolerability of the Chymase Inhibitor Fulacimstat in Patients With Left Ventricular Dysfunction After Myocardial Infarction-Results of the CHIARA MIA 1 Trial

The chymase inhibitor fulacimstat is developed as a first-in-class treatment option for the inhibition of adverse cardiac remodeling in patients with left ventricular dysfunction (LVD) after acute myocardial infarction (MI). The aim of the study was to examine the safety and tolerability of fulacimstat in patients with LVD after remote MI. A multicenter, multinational randomized, placebo-controlled study was performed in clinically stable patients (40-79 years of age, left ventricular ejection fraction ≤ 45% because of MI in medical history) who were on stable evidence-based standard-of-care therapies for LVD post-MI including an angiotensin converting enzyme inhibitor or angiotensin receptor blocker at doses of at least half the recommended target dose. Patients were treated for 2 weeks with either placebo (n = 12) or 4 different doses of fulacimstat (5 mg twice daily, n = 9; 10 mg twice daily, n = 9; 25 mg twice daily, n = 10; 50 mg once daily, n = 9). Fulacimstat was safe and well tolerated at all examined doses. There were no clinically relevant effects on vital signs or potassium levels compared with placebo treatment. Mean plasma concentrations of fulacimstat increased with the administered dose and reached exposures predicted to be therapeutically active. The safety profile and the absence of effects on blood pressure or heart rate in a chronic patient population having similar comorbidities and receiving similar comedication as patients after acute MI support future clinical trials with fulacimstat in patients after acute MI.

Rivaroxaban in Patients with Heart Failure, Sinus Rhythm, and Coronary Disease

BACKGROUND

Heart failure is associated with activation of thrombin-related pathways, which predicts a poor prognosis. We hypothesized that treatment with rivaroxaban, a factor Xa inhibitor, could reduce thrombin generation and improve outcomes for patients with worsening chronic heart failure and underlying coronary artery disease.

METHODS

In this double-blind, randomized trial, 5022 patients who had chronic heart failure, a left ventricular ejection fraction of 40% or less, coronary artery disease, and elevated plasma concentrations of natriuretic peptides and who did not have atrial fibrillation were randomly assigned to receive rivaroxaban at a dose of 2.5 mg twice daily or placebo in addition to standard care after treatment for an episode of worsening heart failure. The primary efficacy outcome was the composite of death from any cause, myocardial infarction, or stroke. The principal safety outcome was fatal bleeding or bleeding into a critical space with a potential for causing permanent disability.

RESULTS

Over a median follow-up period of 21.1 months, the primary end point occurred in 626 (25.0%) of 2507 patients assigned to rivaroxaban and in 658 (26.2%) of 2515 patients assigned to placebo (hazard ratio, 0.94; 95% confidence interval [CI], 0.84 to 1.05; P=0.27). No significant difference in all-cause mortality was noted between the rivaroxaban group and the placebo group (21.8% and 22.1%, respectively; hazard ratio, 0.98; 95% CI, 0.87 to 1.10). The principal safety outcome occurred in 18 patients who took rivaroxaban and in 23 who took placebo (hazard ratio, 0.80; 95% CI, 0.43 to 1.49; P=0.48).

CONCLUSIONS

Rivaroxaban at a dose of 2.5 mg twice daily was not associated with a significantly lower rate of death, myocardial infarction, or stroke than placebo among patients with worsening chronic heart failure, reduced left ventricular ejection fraction, coronary artery disease, and no atrial fibrillation. (Funded by Janssen Research and Development; COMMANDER HF ClinicalTrials.gov number, NCT01877915 .).

Rationale and design of the phase 2b clinical trials to study the effects of the partial adenosine A1-receptor agonist neladenoson bialanate in patients with chronic heart failure with reduced (PANTHEON) and preserved (PANACHE) ejection fraction

Despite major advances in the treatment of chronic heart failure (HF) with reduced ejection fraction (HFrEF), morbidity and mortality associated with the condition remain high, suggesting the need for additional treatment options, particularly haemodynamically neutral treatments that do not alter blood pressure, heart rate, or renal function. HF with preserved ejection fraction (HFpEF) is also associated with high morbidity and mortality and adequate treatment options are limited; thus there is a critical unmet need for the development of novel therapies for HFpEF. Chronic HFrEF and HFpEF are both systemic disorders that affect not only the heart but several other tissues and organs including skeletal muscle, leading to exercise intolerance and dyspnoea. Partial adenosine A1-receptor agonists represent a novel potential therapy for HF regardless of underlying ejection fraction given their minimal effect on heart rate and blood pressure, and preclinical data demonstrate several possible beneficial mechanisms, including improved mitochondrial function and sarcoplasmic reticulum Ca²⁺ -ATPase (SERCA2a) activity, enhanced energy substrate utilization, reverse ventricular remodelling, and anti-ischemic, cardioprotective properties. However, data on this class of drugs in humans are scarce, and the optimal dose of the partial adenosine A1 receptor, neladenoson bialanate, has not been defined. Here we describe the design and rationale of two randomized, double-blind, placebo-controlled, parallel-group, dose-finding phase 2b trials, PANTHEON (HFrEF) and PANACHE (HFpEF), that will advance our understanding of the potential benefit and optimal dose of neladenoson bialanate and provide critical information for the planning of future phase 3 trials.

A Critical Appraisal of Short-Term End Points in Acute Heart Failure Clinical Trials

The prevalence of heart failure continues to grow, and this is accompanied by an increase in hospitalization for acute heart failure. Hospitalization for heart failure results in a trajectory shift of the syndrome and is associated with worsening outcomes, increased mortality risk, and high costs. Numerous clinical trials over the past 2 decades have had limited success, with no single agent shown to improve mortality risk. The lack of success is multifactorial and in part related to inadequate targets and end points selected for intervention, underscoring the need to better understand and define the pathophysiology of acute heart failure. To better inform future drug development, this review critically explores the short-term end points and outcomes that previous phase III acute heart failure trials have examined.

Sudden Death After Hospitalization for Heart Failure With Reduced Ejection Fraction (from the EVEREST Trial)

Patients with chronic heart failure with reduced ejection fraction (HFrEF) benefit from medical and device therapies targeting sudden cardiac death (SCD). Contemporary estimates of SCD risk after hospitalization for heart failure are limited. We describe the incidence, timing, and clinical predictors of SCD after hospitalization for HFrEF (≤40%) in the EVEREST (Efficacy of Vasopressin Antagonism in Heart Failure Outcome Study with Tolvaptan) trial. Multiple logistic regression analyses tested >30 baseline covariates (including treatment randomization, demographics, comorbid conditions, natriuretic peptides, ejection fraction, and medical and device therapies) to identify predictors of 1-year SCD. Of the 4,024 trial patients discharged alive (97%), there were 268 who experienced SCD (7%) and 703 who experienced non-SCD (17%) during median follow-up of 9.9 months. Implantable cardioverter defibrillator use at baseline was 14.5%. Estimates of SCD at 1, 3, 6, and 12 months were 0.8%, 2.3%, 4.1%, and 7.4%, respectively. Most patients were readmitted before SCD (n = 147, 55%). Male gender, black race, diabetes mellitus, and angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker use were potential predictors of 1-year SCD after hospitalization for HFrEF (all p <0.10); however, this final model demonstrated poor discrimination (C-statistic 0.57). In conclusion, in the EVEREST trial, patients hospitalized for HFrEF faced risks of 1-year postdischarge SCD of 7%, which accrued gradually over time, and were balanced with high competing risks of nonsudden death (17%). Traditional clinical characteristics fail to adequately predict SCD risk. Further data are needed to identify patients at greatest relative risk for SCD (compared with non-SCD) after hospitalization for HFrEF.

Mobile health applications in cardiovascular research

Cardiovascular disease is the leading cause of mortality and morbidity globally. With widespread and growing use of smart phones and mobile devices, the use of mobile health (mHealth) in transmission of physiologic parameters and patient-referred symptoms to healthcare providers and researchers, as well as reminders and care plan applications from providers to patients, has potential to revolutionize both clinical care and the conduct of clinical trials with improved designs, data capture, and potentially lower costs. In randomized early phase proof-of-concept studies, focusing on lifestyle intervention, there is evidence that mHealth technology can improve outcomes. By contrast, results from small randomized controlled trials that tested mHealth interventions in heart failure patients were disappointing with inconsistent findings. These inconclusive results could be partially attributed to a lack of methodological rigor (insufficient sample size, quasi-experimental design, inadequate mHealth equipment). Therefore, there is an urgent need to develop systematic evidence-based guidelines and parameters for mHealth to be effectively utilized in cardiovascular clinical trials.

Patient-reported outcomes in the SOluble guanylate Cyclase stimulatoR in heArT failurE patientS with PRESERVED ejection fraction (SOCRATES-PRESERVED) study

AIMS

Exploratory assessment of the potential benefits of the novel soluble guanylate cyclase stimulator vericiguat on health status in patients with heart failure (HF) with preserved ejection fraction.

METHODS AND RESULTS

The SOCRATES-PRESERVED trial randomized patients with chronic HF and ejection fraction ≥ 45% within 4 weeks of decompensation to 12 weeks of treatment with titrated doses of vericiguat (1.25, 2.5, 5, and 10 mg once daily) or placebo. Health status was assessed with the disease-specific Kansas City Cardiomyopathy Questionnaire (KCCQ) and the generic health-related quality of life measure EQ-5D. In total, 477 patients were randomized 12.9 ± 9.0 days after hospitalization or if requiring outpatient treatment with intravenous diuretics for HF. Baseline KCCQ clinical summary score (CSS), a combination of symptom and physical function domains, was 52.3 ± 20.4 in the 10 mg arm and 54.1 ± 23.0 in placebo, and EQ-5D US index score was 0.74 ± 0.2 and 0.73 ± 0.2, respectively. A larger proportion of patients treated with vericiguat in the 10 mg arm, compared with placebo, achieved clinically meaningful improvements in KCCQ-CSS (82.0% vs. 59.0%, number needed to treat = 4.35, P = 0.0052). Important domains of the KCCQ as well as EQ-5D scores demonstrated a dose-dependent relationship with vericiguat. In the 10 mg arm, the mean physical limitations domain increased by +17.2 ± 19.1 at 12 weeks, compared with +4.5 ± 21.6 in placebo (P = 0.0009). The EQ-5D US index score increased by +0.064 ± 0.167 in the 10 mg arm, compared with a decrease of -0.009 ± 0.195 in placebo (P = 0.0461). Improvements in KCCQ and EQ-5D scores paralleled physician-assessed NYHA class and clinical congestion.

CONCLUSION

Vericiguat, in exploratory hypothesis-generating analyses, was associated with clinically important improvements in patients' health status, as assessed by the KCCQ and EQ-5D. Further studies should be conducted to test the hypothesis that vericiguat improves physical functioning and health-related quality of life in patients with HF with preserved ejection fraction.

Dual Vasopressin V1a/V2 Antagonism: The Next Step in Neurohormonal Modulation in Patients With Heart Failure?

Stimulation of the V1a receptor for arginine vasopressin produces myocardial and vascular effects similar to those of angiotensin II while stimulation of the V2 receptor causes fluid retention. There are no data with sustained blockade of the V1a receptor while single-dose experiments suggest benefit. Acute and chronic administration of selective V2 receptor antagonists reliably relieves dyspnea and produces diuresis without adverse effects on renal function or neurohormonal stimulation, either as adjunctive or alternative therapy to loop diuretics, but has not been shown to improve outcomes as adjunctive therapy. Combined antagonism has been tried only in single-dose studies in stable patients or over the short-term in acute heart failure, with encouraging results. Based on the both the pathophysiologic rationale for additional neurohormonal blockade and these results, chronically blocking both receptors, particularly in more congested patients, may offer significant benefit either as adjunctive or alternative therapy to standard diuretics.

Regional Validation and Recalibration of Clinical Predictive Models for Patients With Acute Heart Failure

Background

Heart failure clinical practice guidelines recommend applying validated clinical predictive models (CPMs) to support decision making. While CPMs are now widely available, the generalizability of heart failure CPMs is largely unknown.

Methods and Results

We identified CPMs derived in North America that predict mortality for patients with acute heart failure and validated these models in different world regions to assess performance in a contemporary international clinical trial (N=4133) of patients with acute heart failure treated with guideline‐directed medical therapy. We performed independent external validations of 3 CPMs predicting in‐hospital mortality, 60‐day mortality, and 1‐year mortality, respectively. CPM discrimination decreased in all regional validation cohorts. The median change in area under the receiver operating curve was −0.09 (range −0.05 to −0.23). Regional calibration was highly variable (90th percentile of absolute difference between smoothed observed and predicted values range <1% to >50%). Calibration remained poor after global recalibrations; however, region‐specific recalibration procedures significantly improved regional performance (recalibrated 90th percentile of absolute difference range <1% to 5% across all regions and all models).

Conclusions

Acute heart failure CPM discrimination and calibration vary substantially across different world regions; region‐specific (as opposed to global) recalibration techniques are needed to improve CPM calibration.

Plasma renin activity, response to aliskiren, and clinical outcomes in patients hospitalized for heart failure: the ASTRONAUT trial

AIMS

The direct renin inhibitor, aliskiren, is known to reduce plasma renin activity (PRA), but whether the efficacy of aliskiren varies based on an individual's baseline PRA in patients hospitalized for heart failure (HF) is presently unknown. We characterized the prognostic value of PRA and determined if this risk is modifiable with use of aliskiren.

METHODS AND RESULTS

This pre-specified neurohormonal substudy of ASTRONAUT analysed all patients hospitalized for HF with ejection fraction (EF) ≤40% with available baseline PRA data (n = 1306, 80.9%). Risk associated with baseline PRA and short-term changes in PRA from baseline to 1 month was modelled with respect to 12-month clinical events. Median baseline PRA was 3.0 (interquartile range 0.6-16.4) ng/mL/h. Aliskiren significantly reduced PRA early after treatment initiation through 12-month follow-up compared with placebo (P < 0.001). The lowest baseline PRA quartile (<0.6 ng/mL/h) was independently predictive of lower all-cause mortality [adjusted hazard ratio (HR) 0.50, 95% confidence interval (CI) 0.31-0.81] and the composite of cardiovascular mortality and HF hospitalization (adjusted HR 0.57, 95% CI 0.40-0.79). Delta log-normalized PRA (from baseline to 1 month) was not predictive of either primary endpoint at 12 months (P ≥ 0.43). The prognostic value of baseline PRA and short-term changes in PRA did not vary by randomization to aliskiren or placebo (interaction P ≥ 0.13).

CONCLUSIONS

Plasma renin activity is reduced early and durably by aliskiren, but this did not translate into improved clinical outcomes in ASTRONAUT. Baseline PRA or short-term reduction in PRA do not identify a subgroup who may preferentially benefit from direct renin inhibition. Clinical Trial Registration ClinicalTrials.gov Unique Identifier: NCT00894387.

Lessons learned in acute heart failure

Acute heart failure (HF) is a global pandemic with more than one million admissions to hospital annually in the US and millions more worldwide. Post-discharge mortality and readmission rates remain unchanged and unacceptably high. Although recent drug development programmes have failed to deliver novel therapies capable of reducing cardiovascular morbidity and mortality in patients hospitalized for worsening chronic HF, hospitalized HF registries and clinical trial databases have generated a wealth of information improving our collective understanding of the HF syndrome. This review will summarize key insights from clinical trials in acute HF and hospitalized HF registries over the last several decades, focusing on improving the management of patients with HF and reduced ejection fraction.

Vericiguat in patients with worsening chronic heart failure and preserved ejection fraction: results of the SOluble guanylate Cyclase stimulatoR in heArT failurE patientS with PRESERVED EF (SOCRATES-PRESERVED) study

Aims

To determine tolerability and the optimal dose regimen of the soluble guanylate cyclase stimulator vericiguat in patients with chronic heart failure and preserved ejection fraction (HFpEF).

Methods and results

SOCRATES-PRESERVED was a prospective, randomized, placebo-controlled double-blind, Phase 2b dose-finding study in patients with HFpEF (ejection fraction ≥ 45%). Patients received vericiguat once daily at 1.25 or 2.5 mg fixed doses, or 5 or 10 mg titrated from a 2.5 mg starting dose, or placebo for 12 weeks. The two primary endpoints were change from baseline in log-transformed N-terminal pro-B-type natriuretic peptide (NT-ProBNP) and left atrial volume (LAV) at 12 weeks. Patients (N = 477; 48% women; mean age 73 ± 10 years; baseline atrial fibrillation 40%) were randomized within 4 weeks of HF hospitalization (75%) or outpatient treatment with intravenous diuretics for HF (25%) to vericiguat (n = 384) or placebo (n = 93). In the pooled three highest dose arms change in logNT-proBNP (vericiguat: +0.038 ± 0.782 log(pg/mL), n = 195; placebo: -0.098 ± 0.778 log(pg/mL), n = 73; one-sided P = 0.8991, two-sided P = 0.2017), and change in LAV [vericiguat: -1.7 ± 12.8 mL (n = 194); placebo:  -3.4 ± 12.7 mL (n = 67), one-sided P = 0.8156, two-sided P = 0.3688] were not different from placebo. Vericiguat was well tolerated (adverse events: vericiguat 10 mg arm, 69.8%; placebo, 73.1%), with low discontinuation rates in all groups, and no changes in blood pressure at 10 mg compared with placebo. The pre-specified exploratory endpoint of Kansas City Cardiomyopathy Questionnaire Clinical Summary Score improved in the vericiguat 10 mg arm by mean 19.3 ± 16.3 points [median 19.8 (interquartile range 10.4-30.7)] from baseline (mean difference from placebo 9.2 points).

Conclusion

Vericiguat was well tolerated, did not change NT-proBNP and LAV at 12 weeks compared with placebo but was associated with improvements in quality of life in patients with HFpEF. Given the encouraging results on quality of life, the effects of vericiguat in patients with HFpEF warrant further study, possibly with higher doses, longer follow-up and additional endpoints.

Pre-discharge and early post-discharge troponin elevation among patients hospitalized for heart failure with reduced ejection fraction: findings from the ASTRONAUT trial

AIMS

Troponin levels are commonly elevated among patients hospitalized for heart failure (HF), but the prevalence and prognostic significance of early post-discharge troponin elevation are unclear. This study sought to describe the frequency and prognostic value of pre-discharge and post-discharge troponin elevation, including persistent troponin elevation from the inpatient to outpatient settings.

METHODS AND RESULTS

The ASTRONAUT trial (NCT00894387; http://www.clinicaltrials.gov) enrolled hospitalized HF patients with ejection fraction ≤40% and measured troponin I prior to discharge (i.e. study baseline) and at 1-month follow-up in a core laboratory (elevation defined as >0.04 ng/mL). This analysis included 1469 (91.0%) patients with pre-discharge troponin data. Overall, 41.5% and 29.9% of patients had elevated pre-discharge [median: 0.09 ng/mL; interquartile range (IQR): 0.06-0.19 ng/mL] and 1-month (median: 0.09 ng/mL; IQR: 0.06-0.15 ng/mL) troponin levels, respectively. Among patients with pre-discharge troponin elevation, 60.4% had persistent elevation at 1 month. After adjustment, pre-discharge troponin elevation was not associated with 12-month clinical outcomes. In contrast, 1-month troponin elevation was independently predictive of increased all-cause mortality [hazard ratio (HR) 1.59, 95% confidence interval (CI) 1.18-2.13] and cardiovascular mortality or HF hospitalization (HR 1.28, 95% CI 1.03-1.58) at 12 months. Associations between 1-month troponin elevation and outcomes were similar among patients with newly elevated (i.e. normal pre-discharge) and persistently elevated levels (interaction P ≥ 0.16). The prognostic value of 1-month troponin elevation for 12-month mortality was driven by a pronounced association among patients with coronary artery disease (interaction P = 0.009).

CONCLUSIONS

In this hospitalized HF population, troponin I elevation was common during index hospitalization and at 1-month follow-up. Elevated troponin I level at 1 month, but not pre-discharge, was independently predictive of increased clinical events at 12 months. Early post-discharge troponin I measurement may offer a practical means of risk stratification and should be investigated as a therapeutic target.

Renin-angiotensin blockade in heart failure with preserved ejection fraction: a systematic review and meta-analysis

Studies with angiotensin-converting enzyme inhibitors (ACE-Is) and angiotensin receptor blockers (ARBs) in patients with heart failure with preserved ejection fraction (HFpEF) have yielded inconsistent results. To conduct a systematic review and meta-analysis of all evidence for ACE-I and ARBs in patients with HFpEF, we searched PubMed, Ovid SP, Embase, and Cochrane database to identify randomized trials and observational studies that compared ACE-I or ARBs against placebo or standard therapy in HFpEF patients. Random-effect models were used to pool the data, and I² testing was performed to assess the heterogeneity of the included studies. A total of 13 studies (treatment arm = 8676 and control arm = 8608) were analysed. Pooled analysis of randomized trials for ACE-I and ARBs (n = 6) did not show any effect on all-cause mortality [relative risk (RR) = 1.02, 95% confidence interval (CI) = 0.93-1.11, P = 0.68, I²  = 0%], while results from observational studies showed a significant improvement (RR = 0.91, 95% CI = 0.87-0.95, P = 0.005, I²  = 81.5%). In pooled analyses of all studies, ACE-I showed a reduction of all-cause mortality (RR = 0.91, 95% CI = 0.87-0.95, P = 0.01). There was no reduction in cardiovascular mortality seen, but in pooled analysis of randomized trials, there was a trend towards reduced HF hospitalization risk (RR = 0.91, 95% CI = 0.83-1.01, I²  = 0%, P = 0.074). These data suggest that ACE-I and ARBs may have a role in improving outcomes of patients with HFpEF, underscoring the need for future research with careful patient selection, and trial design and conduct.

Mode of Death in Heart Failure With Preserved Ejection Fraction

Little is known about specific modes of death in patients with heart failure with preserved ejection fraction (HFpEF). Herein, the authors critically appraise the current state of data and offer potential future directions. They conducted a systematic review of 1,608 published HFpEF papers from January 1, 1985, to December 31, 2015, which yielded 8 randomized clinical trials and 24 epidemiological studies with mode-of-death data. Noncardiovascular modes of death represent an important competing risk in HFpEF. Although sudden death accounted for ∼25% to 30% of deaths in trials, its definition is nonspecific; it is unclear what proportion represents arrhythmic deaths. Moving forward, reporting and definitions of modes of death must be standardized and tailored to the HFpEF population. Broad-scale systematic autopsies and long-term rhythm monitoring may clarify the underlying pathology and mechanisms driving mortal events. There is an unmet need for a longitudinal multicenter, global registry of patients with HFpEF to map its natural history.

Developing New Treatments for Heart Failure: Focus on the Heart

Compared with heart failure (HF) care 20 to 30 years ago, there has been tremendous advancement in therapy for ambulatory HF with reduced ejection fraction with the use of agents that block maladaptive neurohormonal pathways. However, during the past decade, with few notable exceptions, the frequency of successful drug development programs has fallen as most novel therapies have failed to offer incremental benefit or raised safety concerns (ie, hypotension). Moreover, no therapy has been approved specifically for HF with preserved ejection fraction or for worsening chronic HF (including acutely decompensated HF). Across the spectrum of HF, preliminary results from many phase II trials have been promising but are frequently followed by unsuccessful phase III studies, highlighting a disconnect in the translational process between basic science discovery, early drug development, and definitive clinical testing in pivotal trials. A major unmet need in HF drug development is the ability to identify homogeneous subsets of patients whose underlying disease is driven by a specific mechanism that can be targeted using a new therapeutic agent. Drug development strategies should increasingly consider therapies that facilitate reverse remodeling by directly targeting the heart itself rather than strictly focusing on agents that unload the heart or target systemic neurohormones. Advancements in cardiac imaging may allow for more focused and direct assessment of drug effects on the heart early in the drug development process. To better understand and address the array of challenges facing current HF drug development, so that future efforts may have a better chance for success, the Food and Drug Administration facilitated a meeting on February 17, 2015, which was attended by clinicians, researchers, regulators, and industry representatives. The following discussion summarizes the key takeaway dialogue from this meeting.

Strategy to identify subjects with diabetes mellitus more suitable for selective echocardiographic screening: The DAVID-Berg study

BACKGROUND

Despite the burden of pre-clinical heart failure (HF) among diabetes mellitus (DM) patients, routine screening echocardiography is not currently recommended. We prospectively assessed risk prediction for HF/death of a screening strategy combining clinical data, electrocardiogram, NTproBNP, and echocardiogram, aiming to identify DM patients more suitable for selective echocardiography.

METHODS

Among 4047 screened subjects aged≥55/≤80years, the DAVID-Berg Study prospectively enrolled 623 outpatients with DM, or hypertension, or known cardiovascular disease but with no HF history/symptoms. The present analysis focuses on data obtained during a longitudinal follow-up of the 219 patients with DM.

RESULTS

Mean age was 68years, 61% were men, and median DM duration was 4.9years. During a median follow-up of 5.2years, 50 subjects developed HF or died. A predictive model using clinical data demonstrated moderate predictive power, which significantly improved by adding electrocardiogram (C-statistic 0.75 versus 0.70; p<0.05), but not NTproBNP (C-statistic 0.72, p=0.20). Subjects with normal clinical variables or abnormal clinical variables but normal electrocardiogram had low events rate (1.3 versus 2.4events/100-person-years, p=NS). Conversely, subjects with both clinical and electrocardiogram abnormalities (47%) carried higher risk (9.0events/100-person-years, p<0.001). The predictive power for mortality/HF development increased when echocardiography was added (13.6events/100-person-years, C-statistic 0.80, p<0.05).

CONCLUSIONS

Our prospective study found that a selective echocardiographic screening strategy guided by abnormal clinical/electrocardiogram data can reliably identify DM subjects at higher risk for incident HF and death. This screening approach may hold promise in guiding HF prevention efforts among DM patients.

Hyperkalemia in Heart Failure

Disorders of potassium homeostasis can potentiate the already elevated risk of arrhythmia in heart failure. Heart failure patients have a high prevalence of chronic kidney disease, which further heightens the risk of hyperkalemia, especially when renin-angiotensin-aldosterone system inhibitors are used. Acute treatment for hyperkalemia may not be tolerated in the long term. Recent data for patiromer and sodium zirconium cyclosilicate, used to treat and prevent high serum potassium levels on a more chronic basis, have sparked interest in the treatment of hyperkalemia, as well as the potential use of renin-angiotensin-aldosterone system inhibitors in patients who were previously unable to take these drugs or tolerated only low doses. This review discusses the epidemiology, pathophysiology, and outcomes of hyperkalemia in heart failure; provides an overview of traditional and novel ways to approach management of hyperkalemia; and discusses the need for further research to optimally treat heart failure.

Reassessing Phase II Heart Failure Clinical Trials: Consensus Recommendations

The increasing burden and the continued suboptimal outcomes for patients with heart failure underlines the importance of continued research to develop novel therapeutics for this disorder. This can only be accomplished with successful translation of basic science discoveries into direct human application through effective clinical trial design and execution that results in a substantially improved clinical course and outcomes. In this respect, phase II clinical trials play a pivotal role in determining which of the multitude of potential basic science discoveries should move to the large and expansive registration trials in humans. A critical examination of the phase II trials in heart failure reveals multiple shortcomings in their concept, design, execution, and interpretation. To further a dialogue on the challenges and potential for improvement and the role of phase II trials in patients with heart failure, the Food and Drug Administration facilitated a meeting on October 17, 2016, represented by clinicians, researchers, industry members, and regulators. This document summarizes the discussion from this meeting and provides key recommendations for future directions.

Employing Extracellular Volume Cardiovascular Magnetic Resonance Measures of Myocardial Fibrosis to Foster Novel Therapeutics

Quantifying myocardial fibrosis (MF) with myocardial extracellular volume measures acquired during cardiovascular magnetic resonance promises to transform clinical care by advancing pathophysiologic understanding and fostering novel therapeutics. Extracellular volume quantifies MF by measuring the extracellular compartment depicted by the myocardial uptake of contrast relative to plasma. MF is a key domain of dysfunctional but viable myocardium among others (eg, microvascular dysfunction and cardiomyocyte/mitochondrial dysfunction). Although anatomically distinct, these domains may functionally interact. MF represents pathological remodeling in the heart associated with cardiac dysfunction and adverse outcomes likely mediated by interactions with the microvasculature and the cardiomyocyte. Reversal of MF improves key measures of cardiac dysfunction, so reversal of MF represents a likely mechanism for improved outcomes. Instead of characterizing the myocardium as homogenous tissue and using important yet still generic descriptors, such as thickness (hypertrophy) and function (diastolic or systolic), which lack mechanistic specificity, paradigms of cardiac disease have evolved to conceptualize myocardial disease and patient vulnerability based on the extent of disease involving its various compartments. Specifying myocardial compartmental involvement may then implicate cellular/molecular disease pathways for treatment and targeted pharmaceutical development and above all highlight the role of the cardiac-specific pathology in heart failure among myriad other changes in the heart and beyond. The cardiology community now requires phase 2 and 3 clinical trials to examine strategies for the regression/prevention of MF and eventually biomarkers to identify MF without reliance on cardiovascular magnetic resonance. It seems likely that efficacious antifibrotic therapy will improve outcomes, but definitive data are needed.

Exploring New Endpoints for Patients With Heart Failure With Preserved Ejection Fraction

The epidemiological, clinical, and societal implications of the heart failure (HF) epidemic cannot be overemphasized. Approximately half of all HF patients have HF with preserved ejection fraction (HFpEF). HFpEF is largely a syndrome of the elderly, and with aging of the population, the proportion of patients with HFpEF is expected to grow. Currently, there is no drug known to improve mortality or hospitalization risk for these patients. Besides mortality and hospitalization, it is imperative to realize that patients with HFpEF have significant impairment in their functional capacity and their quality of life on a daily basis, underscoring the need for these parameters to ideally be incorporated within a regulatory pathway for drug approval. Although attempts should continue to explore therapies to reduce the risk of mortality or hospitalization for these patients, efforts should also be directed to improve other patient-centric concerns, such as functional capacity and quality of life. To initiate a dialogue about the compelling need for and the challenges in developing such alternative endpoints for patients with HFpEF, the US Food and Drug Administration on November 12, 2015, facilitated a meeting represented by clinicians, academia, industry, and regulatory agencies. This document summarizes the discussion from this meeting.

Is there a clinically meaningful difference in patient reported dyspnea in acute heart failure? An analysis from URGENT Dyspnea

BACKGROUND

Dyspnea is the most common presenting symptom in patients with acute heart failure (AHF), but is difficult to quantify as a research measure. The URGENT Dyspnea study compared 3 scales: (1) 10 cm VAS, (2) 5-point Likert, and (3) a 7-point Likert (both VAS and 5-point Likert were recorded in the upright and supine positions). However, the minimal clinically important difference (MCID) to patients has not been well established.

METHODS

We performed a secondary analysis from URGENT Dyspnea, an observational, multi-center study of AHF patients enrolled within 1 h of first physician assessment in the ED. Using the anchor-based method to determine the MCID, a one-category change in the 7-point Likert was used as the criterion standard ('minimally improved or worse'). The main outcome measures were the change in visual analog scale (VAS) and 5-point Likert scale from baseline to 6-h assessment relative to a 1-category change response in the 7-point Likert scale ('minimally worse', 'no change', or 'minimally better').

RESULTS

Of the 776 patients enrolled, 491 had a final diagnosis of AHF with responses at both time points. A 10.5 mm (SD 1.6 mm) change in VAS was the MCID for improvement in the upright position, and 14.5 mm (SD 2.0 mm) in the supine position. However, there was no MCID for worsening, as few patients reported worse dyspnea. There was also no significant MCID for the 5-point Likert scale.

CONCLUSION

A 10.5 mm change is the MCID for improvement in dyspnea over 6 h in ED patients with AHF.

Influence of atrial fibrillation on post-discharge natriuretic peptide trajectory and clinical outcomes among patients hospitalized for heart failure: insights from the ASTRONAUT trial

AIMS

Change in NT-proBNP level is a common surrogate endpoint in early phase heart failure (HF) trials, but whether this endpoint is influenced by atrial fibrillation/flutter (AFF) is unclear.

METHODS AND RESULTS

This analysis included 1358 patients from the ASTRONAUT trial, which randomized patients hospitalized for HF with EF ≤40% to aliskiren or placebo in addition to standard care. Patients were stratified by presence of AFF on baseline ECG. NT-proBNP was measured longitudinally by a core laboratory at baseline, 1 month, 6 months, and 12 months. Compared with non-AFF patients, AFF patients experienced greater reduction from baseline in log-transformed NT-proBNP (interaction P < 0.001), but this difference was not significant after adjustment (interaction P = 0.726). The ability of aliskiren to lower NT-proBNP during follow-up differed by AFF status (interaction P = 0.001), with aliskiren lowering NT-proBNP more than placebo among non-AFF patients only. After adjustment, baseline AFF was not associated with mortality or HF hospitalization at 12 months (all P ≥ 0.152).

CONCLUSION

In this hospitalized HF cohort, AFF status did not influence post-discharge NT-proBNP trajectory or clinical outcomes after adjustment for patient characteristics. Aliskiren lowered follow-up NT-proBNP levels in patients without AFF, but had no influence among patients with AFF. This study generates the hypothesis that the ability of a HF trial to meet an NT-proBNP defined endpoint may be influenced by the prevalence of AFF in the population. Because aliskiren did not improve outcomes in patients without AFF, this analysis suggests changes in NT-proBNP induced by investigational therapies may be dissociated from clinical effects.

Drug Development for Heart Failure With Preserved Ejection Fraction: What Pieces Are Missing From the Puzzle?

Despite the growing number of patients with heart failure with preserved ejection fraction (HFpEF) and event rates comparable with many cancers, there remain no pharmacologic agents definitively proven to improve patient outcomes. Although phase II trials have intermittently yielded encouraging results, none have translated into successful achievement of a phase III primary end point. Thus, because of the urgent need to discover proven therapies, it is prudent to reevaluate our current approach to HFpEF drug development. In this review, we comment on key areas of uncertainty and importance relevant to successful drug discovery for HFpEF. These areas include the need to: clarify and homogenize the HFpEF definition; better understand the role of comorbidities and varying HFpEF etiology; use the heart failure hospitalization as the prime opportunity for trial enrollment; classify HFpEF patients within discrete clinicopathologic phenotypes for selected study; discover novel molecular drug targets; and determine predictors of specific causes of death to allow optimal matching of pharmacologic mechanisms with HFpEF subgroups most likely to benefit. Recognizing that the study of HFpEF is inherently challenging and complex, addressing these specific areas and overcoming their respective hurdles might maximize the chances of discovering a beneficial therapy.

Predictors of Post-discharge Mortality Among Patients Hospitalized for Acute Heart Failure

Acute Heart Failure (AHF) is a " multi-event disease" and hospitalisation is a critical event in the clinical course of HF. Despite relatively rapid relief of symptoms, hospitalisation for AHF is followed by an increased risk of death and re-hospitalisation. In AHF, risk stratification from clinically available data is increasingly important in evaluating long-term prognosis. From the perspective of patients, information on the risk of mortality and re-hospitalisation would be helpful in providing patients with insight into their disease. From the perspective of care providers, it may facilitate management decisions, such as who needs to be admitted and to what level of care (i.e. floor, step-down, ICU). Furthermore, risk-stratification may help identify patients who need to be evaluated for advanced HF therapies (i.e. left-ventricle assistance device or transplant or palliative care), and patients who need early a post-discharge follow-up plan. Finally, risk stratification will allow for more robust efforts to identify among risk markers the true targets for therapies that may direct treatment strategies to selected high-risk patients. Further clinical research will be needed to evaluate if appropriate risk stratification of patients could improve clinical outcome and resources allocation.

Expert consensus document: Mitochondrial function as a therapeutic target in heart failure

Heart failure is a pressing worldwide public-health problem with millions of patients having worsening heart failure. Despite all the available therapies, the condition carries a very poor prognosis. Existing therapies provide symptomatic and clinical benefit, but do not fully address molecular abnormalities that occur in cardiomyocytes. This shortcoming is particularly important given that most patients with heart failure have viable dysfunctional myocardium, in which an improvement or normalization of function might be possible. Although the pathophysiology of heart failure is complex, mitochondrial dysfunction seems to be an important target for therapy to improve cardiac function directly. Mitochondrial abnormalities include impaired mitochondrial electron transport chain activity, increased formation of reactive oxygen species, shifted metabolic substrate utilization, aberrant mitochondrial dynamics, and altered ion homeostasis. In this Consensus Statement, insights into the mechanisms of mitochondrial dysfunction in heart failure are presented, along with an overview of emerging treatments with the potential to improve the function of the failing heart by targeting mitochondria.

Intravenous Allogeneic Mesenchymal Stem Cells for Nonischemic Cardiomyopathy: Safety and Efficacy Results of a Phase II-A Randomized Trial

RATIONALE

Potential benefits of mesenchymal stem cell (MSC) therapy in heart failure may be related to paracrine properties and systemic effects, including anti-inflammatory activities. If this hypothesis is valid, intravenous administration of MSCs should improve outcomes in heart failure, an entity in which excessive chronic inflammation may play a pivotal role.

OBJECTIVE

To assess the safety and preliminary efficacy of intravenously administered ischemia-tolerant MSCs (itMSCs) in patients with nonischemic cardiomyopathy.

METHODS AND RESULTS

This was a single-blind, placebo-controlled, crossover, randomized phase II-a trial of nonischemic cardiomyopathy patients with left ventricular ejection fraction ≤40% and absent hyperenhancement on cardiac magnetic resonance imaging. Patients were randomized to intravenously administered itMSCs (1.5×10⁶ cells/kg) or placebo; at 90 days, each group received the alternative treatment. Overall, 22 patients were randomized to itMSC (n=10) and placebo (n=12) at baseline. After crossover, data were available for 22 itMSC patients. No major differences in death, hospitalization, or serious adverse events were noted between the 2 treatments. Change from baseline in left ventricular ejection fraction and ventricular volumes was not significantly different between therapies. Compared with placebo, itMSC therapy increased 6-minute walk distance (+36.47 m, 95% confidence interval 5.98-66.97; P=0.02) and improved Kansas City Cardiomyopathy clinical summary (+5.22, 95% confidence interval 0.70-9.74; P=0.02) and functional status scores (+5.65, 95% confidence interval -0.11 to 11.41; P=0.06). The data demonstrated MSC-induced immunomodulatory effects, the magnitude of which correlated with improvement in left ventricular ejection fraction.

CONCLUSIONS

In this pilot study of patients with nonischemic cardiomyopathy, itMSC therapy was safe, caused immunomodulatory effects, and was associated with improvements in health status and functional capacity.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02467387.