A dose-dependent increase in mortality with vesnarinone among patients with severe heart failure. Vesnarinone Trial Investigators

Rosmarinus officinalis L. (rosemary) as therapeutic and prophylactic agent

Rosmarinus officinalis L. (rosemary) is a medicinal plant native to the Mediterranean region and cultivated around the world. Besides the therapeutic purpose, it is commonly used as a condiment and food preservative. R. officinalis L. is constituted by bioactive molecules, the phytocompounds, responsible for implement several pharmacological activities, such as anti-inflammatory, antioxidant, antimicrobial, antiproliferative, antitumor and protective, inhibitory and attenuating activities. Thus, in vivo and in vitro studies were presented in this Review, approaching the therapeutic and prophylactic effects of R. officinalis L. on some physiological disorders caused by biochemical, chemical or biological agents. In this way, methodology, mechanisms, results, and conclusions were described. The main objective of this study was showing that plant products could be equivalent to the available medicines.

Ambulatory Intravenous Inotropic Support and or Levosimendan in Pediatric and Congenital Heart Failure: Safety, Survival, Improvement, or Transplantation

End-stage heart failure (HF) frequently needs continuous inotropic support in hospital and has high morbidity and mortality in absence of heart transplantation. This study reports outcome, efficacy, and safety of continuous ambulatory inotropes (AI) and/or periodic levosimendan (LS) infusions in pediatric HF patients. The study included 27 patients, median age 9.4 (0.1-26.1) years, with severe HF (6 myocarditis, 13 dilated cardiomyopathy, 2 restrictive cardiomyopathy, 6 repaired congenital heart disease). Dobutamine and milrinone AI were administered in 21 patients through a permanent central catheter for median duration 1.0 (0.3-3.7) years. Additionally, 14 AI patients and the remaining 6 study patients received periodic LS infusions for median duration 1.1 (0.2-4.2) years. During median follow-up 2.1 (0.3-21.3) years, 4 patients died of worsening HF after 0.8-2.1 years AI, 6 patients underwent heart transplantation with only 3 survivors, while the rest remained stable out of the hospital with complications 4 line infections treated with antibiotics and 4 catheter reinsertions due to dislodgement. Severe pulmonary hypertension was reversed with AI in 2 patients, allowing successful heart-only transplantation. Therapy with AI was discontinued after 1.4-0.4 years in 6 improved myocarditis and 3 cardiomyopathy patients without deterioration. In conclusion, prolonged AI and/or LS infusions in HF are safe and beneficial even in small infants, allowing stabilization and reasonable social and family life out of the hospital. It may provide precious time for heart transplantation or myocardial remodeling, improvement, and possible discontinuation even after long periods of support.

Exploration of diphenylalkyloxadiazoles as novel cardiac myosin activator

To explore novel cardiac myosin activator, a series of diphenylalkyl substituted 1,3,4-oxadiazoles and 1,2,4-oxadiazoles have been prepared and tested for cardiac myosin ATPase activation in vitro. In all cases, three carbon spacer between the oxadiazole core and one of the phenyl ring was considered crucial. In case of 1,3,4-oxadiazole, zero to two carbon spacer between oxadiazole core and other phenyl ring are favorable. Phenyl ring can be replaced by cyclohexyl moiety. In case of 1,2,4-oxadiazole, zero or one carbon spacer between the oxadiazole and other phenyl ring are favorable. Introduction of hydrogen bonding donor (NH) group at the 2^nd position of the 1,3,4-oxadiazole enhances the activity. Substitutions on either of the phenyl rings or change of phenyl ring to other heterocycle are not tolerated for both the oxadiazoles. The prepared oxadiazoles showed selective activation for cardiac muscle over smooth and skeleton muscles.

Acute heart failure management in the USA and Japan: overview of practice patterns and review of evidence

Globally, acute heart failure (AHF) remains an ongoing public health issue with its prevalence and mortality increasing in the east and the west. Effective treatment strategies to stabilize AHF are important to alleviate clinical symptoms and to improve clinical outcomes. However, despite the progress in the management of stable and chronic heart failure, no single agent has been proven to play a definitive role in the management of AHF. As a consequence, contemporary treatment strategies for patients with AHF vary greatly by region. This manuscript reviews the medical treatment options for AHF, with an emphasis on the differences between the treatment strategies in the USA and Japan. This information would provide a framework for clinicians to evaluate and manage patients with AHF and highlight the remaining questions to improve clinical outcomes.

The independent statistician model: How well is it working?

With the initiation in the late 1960s of the data and safety monitoring board or equivalently the data monitoring committee in randomized clinical trials came the need for interim statistical reports for these committees to review for study conduct and early evidence of harm or overwhelming evidence of benefit, perhaps leading to early trial termination. Initially, the statistical team was part of the data coordinating center for the trial. Later, starting in the early 1990s in many industry-sponsored trials, this statistical unit was separated organizationally from the team that collected and managed the data. This unit, often referred to as the statistical data analysis center, prepares reports for the data monitoring committee, which cover study conduct, data quality and completeness, primary and secondary outcomes, and safety measures by study arm in an unblinded fashion. The role of the statistical data analysis center is critical to any well-functioning data monitoring committee. With the proliferation of data monitoring committees has grown the need for many more well-trained and experienced statistical data analysis centers. In my experience, some such units perform their tasks extremely well but many do not. There is a tremendous need and opportunity to provide training for statistical data analysis centers, and what sponsors and data monitoring committees should expect from statistical data analysis centers.

Functions of PDE3 Isoforms in Cardiac Muscle

Isoforms in the PDE3 family of cyclic nucleotide phosphodiesterases have important roles in cyclic nucleotide-mediated signalling in cardiac myocytes. These enzymes are targeted by inhibitors used to increase contractility in patients with heart failure, with a combination of beneficial and adverse effects on clinical outcomes. This review covers relevant aspects of the molecular biology of the isoforms that have been identified in cardiac myocytes; the roles of these enzymes in modulating cAMP-mediated signalling and the processes mediated thereby; and the potential for targeting these enzymes to improve the profile of clinical responses.

Levosimendan: new indications and evidence for reduction in perioperative mortality?

PURPOSE OF REVIEW

In the last years, the perioperative use of levosimendan in cardiac surgery patients is spreading. Moreover, newer indications have been suggested such as the treatment of sepsis-associated myocardial dysfunction. In the present review, we discuss the most recent evidences in these settings.

RECENT FINDINGS

Levosimendan has been seemingly confirmed to reduce mortality in patients undergoing cardiac surgery. In particular, it appears to be the only inotropic drug to have a favorable effect on survival in any clinical setting. Moreover, levosimendan has been shown to exert a cardioprotective action and to reduce acute kidney injury, renal replacement therapy, and ICU stay in cardiac surgery patients. Finally, levosimendan has been suggested to reduce mortality in patients with severe sepsis and to improve renal outcomes in critically ill patients.

SUMMARY

Although a strong rationale likely exists to use levosimendan in the setting of perioperative and critical care medicine, evidence mainly comes from small and often poor-quality randomized clinical trials, whose results acquire significance only when pooled in meta-analyses. Moreover, some aspects related to which subgroups of patients may derive the most benefits from receiving levosimendan, to the optimal timing of administration, and to the potential adverse effects need to be further clarified. Important insights will be hopefully provided soon by the several large multicenter investigations which are currently ongoing.

Developing Drugs for Heart Failure With Reduced Ejection Fraction: What Have We Learned From Clinical Trials?

There remains a large unmet need for new therapies in the treatment of heart failure with reduced ejection fraction (HFrEF). In the early drug development phase, the therapeutic potential of a drug is not yet fully understood and trial endpoints other than mortality are needed to guide drug development decisions. While a true surrogate marker for mortality in heart failure (HF) remains elusive, the successes and failures of previous trials can reveal markers that support clinical Go/NoGo decisions.

Cardiac Myosin Activation with Gene Therapy Produces Sustained Inotropic Effects and May Treat Heart Failure with Reduced Ejection Fraction

Chronic inotropic therapy is effective for the treatment of heart failure with reduced ejection fraction, but has been limited by adverse long-term safety profiles, development of tolerance, and the need for chronic parenteral administration. A safe and convenient therapeutic agent that produces sustained inotropic effects could improve symptoms, functional capacity, and quality of life. Small amounts of 2-deoxy-adenosine triphosphate (dATP) activate cardiac myosin leading to enhanced contractility in normal and failing heart muscle. Cardiac myosin activation triggers faster myosin crossbridge cycling with greater force generation during each contraction. This paper describes the rationale and results of a translational medicine effort to increase dATP levels using a gene therapy strategy to deliver and upregulate ribonucleotide reductase (R1R2), the enzyme responsible for dATP synthesis, selectively in cardiomyocytes. In small and large animal models of heart failure, a single dose of this gene therapy has led to sustained inotropic effects with a benign safety profile. Further animal studies are appropriate with the goal of testing this agent in patients with heart failure.

Korean Guidelines for Diagnosis and Management of Chronic Heart Failure

The prevalence of heart failure (HF) is skyrocketing worldwide, and is closely associated with serious morbidity and mortality. In particular, HF is one of the main causes for the hospitalization and mortality in elderly individuals. Korea also has these epidemiological problems, and HF is responsible for huge socioeconomic burden. However, there has been no clinical guideline for HF management in Korea. 
The present guideline provides the first set of practical guidelines for the management of HF in Korea and was developed using the guideline adaptation process while including as many data from Korean studies as possible. The scope of the present guideline includes the definition, diagnosis, and treatment of chronic HF with reduced/preserved ejection fraction of various etiologies.

Reporting of Lost to Follow-Up and Treatment Discontinuation in Pharmacotherapy and Device Trials in Chronic Heart Failure: A Systematic Review

BACKGROUND

Premature treatment discontinuation and loss to follow-up (LTFU) with unknown outcomes leave uncertainty about the true efficacy and safety of a treatment and a lack of confidence in the results of any trial. We reviewed the extent of (and trends over time in) reporting LTFU and treatment discontinuation in large studies in chronic heart failure published since 1990.

METHODS AND RESULTS

Online databases were systematically reviewed to identify randomized controlled clinical trials (RCTs) in chronic heart failure with >400 participants and utilizing all-cause mortality as a component of the primary or secondary end point. Assessments were made of documentation of treatment discontinuation, LTFU, inclusion of and completeness of a Consolidated Standards Of Reporting Trials (CONSORT) diagram, and whether LTFU was differentiated from withdrawal of consent. Sixty-eight trials were identified, with >154 000 participants. Reasons for treatment discontinuation in pharmacotherapy trials were infrequently reported (35%), particularly in a CONSORT diagram (20%). Eighty-three percent of trials reported LTFU, although only 34% of these differentiated LTFU for vital status from withdrawal of consent. Use of a CONSORT diagram increased over time, although reporting of LTFU in the CONSORT diagram remained low overall at 35%.

CONCLUSIONS

Participant flow through RCTs in chronic heart failure has not been uniformly reported, and the use of a complete CONSORT diagram has been low, although it seems to be improving. All study participants should be accounted for within a CONSORT diagram in any RCT to enable the practicing cardiologist to interpret how the results should influence his/her clinical practice.

Treatment of Heart Failure with Abnormal Left Ventricular Systolic Function in Older Adults

Heart failure (HF) with abnormal left ventricular (LV) ejection fraction should be identified and treated. Treat hypertension with diuretics, angiotensin-converting enzyme (ACE) inhibitors, and β-blockers. Treat myocardial ischemia with nitrates and β-blockers. Treat volume overload and HF with diuretics. Treat HF with ACE inhibitors and β-blockers. Sacubitril/valsartan may be used instead of an ACE inhibitor or ARB in chronic symptomatic HF and abnormal LV ejection fraction. Add isosorbide dinitrate/hydralazine in African Americans with class II to IV HF treated with diuretics, ACE inhibitors, and β-blockers. Exercise training is recommended. Indications for implantable cardioverter-defibrillator and cardiac resynchronization therapy are discussed.

Nutritional screening based on the controlling nutritional status (CONUT) score at the time of admission is useful for long-term prognostic prediction in patients with heart failure requiring hospitalization

The objective of the study was to clarify whether controlling nutritional status (CONUT) is useful for predicting the long-term prognosis of patients hospitalized with heart failure (HF). A total of 482 (57.5%) HF patients from the Ibaraki Cardiovascular Assessment Study-HF (N = 838) were enrolled (298 men, 71.7 ± 13.6 years). At admission, blood samples were collected and nutritional status assessed using CONUT. CONUT scores were defined as follows: 0-1, normal; 2-4, light; 5-8, moderate; and 9-12, severe undernutrition. Accordingly, 352 (73%) patients had light-to-severe nutritional disturbances. In the follow-up period [median 541.5 (range 354-786) days], 109 deaths were observed. A Kaplan-Meier analysis revealed that all-cause deaths occurred more frequently in HF patients with nutritional disturbances [n = 93 (26.4%)] than in those with normal nutrition [n = 16 (12.3%); log-rank p < 0.001]. The Cox proportional hazard analyses revealed that a per point increase in the CONUT score was associated with an increased risk of all-cause death (hazard ratio 1.142; 95% confidence interval, 1.044-1.249) after controlling simultaneously for age, sex, previous history of HF hospitalization, log brain natriuretic peptide, and use of therapeutic agents at admission (tolvaptan and aldosterone antagonists). This study suggests that nutritional screening using CONUT scores is helpful in predicting the long-term prognosis of patients hospitalized with HF in a multicenter registry setting.

Long-Term Effects of Flosequinan on the Morbidity and Mortality of Patients With Severe Chronic Heart Failure: Primary Results of the PROFILE Trial After 24 Years

OBJECTIVES

The purpose of this clinical trial was to evaluate the long-term effects of flosequinan on the morbidity and mortality of patients with severe chronic heart failure.

BACKGROUND

Flosequinan was the first oral vasodilator to be used in the clinic to augment the effects of digitalis, diuretics, and angiotensin-converting enzyme inhibitors in heart failure. However, the drug activated neurohormonal systems and exerted both positive inotropic and chronotropic effects, raising concerns about its safety during long-term use.

METHODS

Following a run-in period designed to minimize the risk of tachycardia, we randomly assigned 2,354 patients in New York Heart Association functional class III to IV heart failure and with an ejection fraction ≤35% to receive long-term treatment with placebo or flosequinan (75 or 100 mg/day) in addition to their usual therapy. The primary outcome was all-cause mortality.

RESULTS

The trial was terminated after a recommendation of the Data and Safety Monitoring Board, because during an average of 10 months of follow-up, 192 patients died in the placebo group and 255 patients died in the flosequinan group (hazard ratio: 1.39, 95% confidence interval: 1.15 to 1.67; p = 0.0006). Flosequinan also increased the risk of disease progression, which was paralleled by drug-related increases in heart rate and neurohormonal activation. However, during the first month, patients in the flosequinan group were more likely to report an improvement in well-being and less likely to experience worsening heart failure. Similarly, during the month following drug withdrawal at the end of the trial, patients withdrawn from flosequinan were more likely than those withdrawn from placebo to report symptoms of or to require treatment for worsening heart failure.

CONCLUSIONS

Although flosequinan produced meaningful symptomatic benefits during short- and long-term treatment, the drug increased the risk of death in patients with severe chronic heart failure.

Development and Evolution of a Hierarchical Clinical Composite End Point for the Evaluation of Drugs and Devices for Acute and Chronic Heart Failure: A 20-Year Perspective

Traditional approaches to the assessment of new treatments for heart failure have generally evaluated individual components of the syndrome at fixed points in time or have relied on surrogate physiological measures that are poorly correlated with the clinical status of patients. Conventional time-to-event trials that focus on morbidity and mortality represent an important methodological advance, but they generally assign undue weight to clinical events of less importance and are insensitive to difference in functional capacity among individuals who do not experience a clinical event during follow-up. Twenty years ago, a hierarchical clinical composite was developed to address these limitations; it aims to assess the clinical course of patients as a physician would in practice by combining a symptomatic assessment of the patient at each visit with an evaluation of the clinical stability of the patient between visits. The composite does not generate a numeric score by summing arbitrarily assigned weights to certain symptoms or events; instead, the composite ranks relevant measures and outcomes according to clinical priority. In doing so, the clinical composite minimizes the biases created by noncompleting patients in the assessment of symptoms or exercise tolerance while expanding the range of patients who contribute to the treatment difference in a typical morbidity and mortality trial. When applied appropriately, the hierarchical clinical composite end point has reliably distinguished effective from ineffective treatments. The composite may have particular advantages in the evaluation of new devices and transcatheter interventions in chronic heart failure and of new drugs for acute heart failure. Recent modifications enhance its discriminant characteristics and its ability to accurately assess the efficacy of novel interventions for heart failure.

New developments in the pharmacotherapeutic management of heart failure in elderly patients: concerns and considerations

INTRODUCTION

Heart failure (HF) remains a major public health problem worldwide, affecting approximately 23 million patients, and is predominantly a disease of the elderly population. Elderly patients mostly suffer from HF with preserved ejection fraction (HFpEF), which often presents with multiple co-morbidities and they require multiple medical treatments. This, together with the heterogeneous phenotype of HFpEF, makes it a difficult syndrome to diagnose and treat. Areas covered: Although HF is most abundant in the elderly, this group is still underrepresented in clinical trials, which results in the lack of evidence-based medical regimens. The current review has focused on new potential therapies for this poorly studied population. The focus will be on several classes of drugs currently recommended or might be expected soon. These will include sacubitril/valsartan (former LCZ696), Omecamtiv mecarbil, Vericiguat, Ivabradine, mineralocorticoid receptor antagonists (MRAs) and potassium binders. Expert opinion: We discuss promising new treatments and hypothesize that personalized approaches will be needed to treat elderly patients optimally. Medical doctors should not only focus on HF therapy, but comorbidities and polypharmacy should also influence therapeutic decision making. Furthermore, the importance of quality of life as a management endpoint should not be underestimated in the frail elderly.

ERBB signaling attenuates proinflammatory activation of nonclassical monocytes

Immune activation in chronic systolic heart failure (HF) correlates with disease severity and prognosis. Recombinant neuregulin-1 (rNRG-1) is being developed as a possible therapy for HF, based on the activation of ERBB receptors in cardiac cells. Work in animal models of HF led us to hypothesize that there may be direct effects of NRG-1 on immune system activation and inflammation. We investigated the expression of ERBB receptors and the effect of rNRG-1 isoform glial growth factor 2 (GGF2) in subpopulations of peripheral blood mononuclear cells (PB MNCs) in subjects with HF. We found that human monocytes express both ERBB2 and ERBB3 receptors, with high interindividual variability among subjects. Monocyte surface ERBB3 and TNF-α mRNA expression were inversely correlated in subjects with HF but not in human subjects without HF. GGF2 activation of ERBB signaling ex vivo inhibited LPS-induced TNF-α production, specifically in the CD14^lowCD16⁺ population of monocytes in a phosphoinositide 3-kinase-dependent manner. GGF2 suppression of TNF-α correlated directly with the expression of ERBB3. In vivo, a single dose of intravenous GGF2 reduced TNF-α expression in PB MNCs of HF subjects participating in a phase I safety study of GGF2. These results support a role for ERBB3 signaling in the regulation of TNF-α production from CD14^lowCD16⁺ monocytes and a need for further investigation into the clinical significance of NRG-1/ERBB signaling as a modulator of immune system function.NEW & NOTEWORTHY This study identified a novel role of neuregulin-1 (NRG-1)/ERBB signaling in the control of proinflammatory activation of monocytes. These results further improve our fundamental understanding of cardioprotective effects of NRG-1 in patients with heart failure.

Synthesis and Positive Inotropic Activity of [1,2,4]Triazolo[4,3-a] Quinoxaline Derivatives Bearing Substituted Benzylpiperazine and Benzoylpiperazine Moieties

In an attempt to search for more potent positive inotropic agents, two series of [1,2,4]triazolo[4,3-a] quinoxaline derivatives bearing substituted benzylpiperazine and benzoylpiperazine moieties were synthesized and their positive inotropic activities evaluated by measuring left atrial stroke volume in isolated rabbit heart preparations. Several compounds showed favorable activities compared with the standard drug, milrinone. Compound 6c was the most potent agent, with an increased stroke volume of 12.53% ± 0.30% (milrinone: 2.46% ± 0.07%) at 3 × 10⁻⁵ M. The chronotropic effects of compounds having considerable inotropic effects were also evaluated.

Direct Myosin Activation by Omecamtiv Mecarbil for Heart Failure with Reduced Ejection Fraction

Myosin is the indispensable molecular motor that utilizes chemical energy to produce force for contraction within the cardiac myocyte. Myosin activity is gated by intracellular calcium levels which are regulated by multiple upstream signaling cascades that can be altered for clinical utility using inotropic medications. In contrast to clinically available cardiac inotropes, omecamtiv mecarbil is a novel direct myosin activator developed to augment left ventricular systolic function without the undesirable secondary effects of altered calcium homeostasis. Its identification and synthesis followed high-throughput screening of a reconstituted sarcomere, deliberate optimization, exquisite biochemical evaluation, and subsequently promising effects in animal models were demonstrated. Physiologically, it prolonged the duration of left ventricular systole in animal models, healthy adults, and patients with heart failure with reduced ejection fraction (HFrEF) without changing the velocity of pressure development, as assessed in animal models. It has been formulated for both intravenous and oral administration, and in both acute and chronic settings produced similar alterations in the duration of systole associated with beneficial increases in cardiac output, improvements in left ventricular volumes, and reductions in heart rate and often of natriuretic peptides. Small, asymptomatic increases in troponin were also observed in the absence of clinically evident ischemia. Clinically, the question remains as to whether the possible harm of this minimal troponin release is outweighed by the potential benefits of reduced neurohormonal activation, increased stroke volume and cardiac output, and improved ventricular remodeling in patients treated with omecamtiv mecarbil. The resolution of this question is being addressed by a phase III outcomes trial of this potential novel therapy for heart failure.

Translation of Cardiac Myosin Activation with 2-deoxy-ATP to Treat Heart Failure via an Experimental Ribonucleotide Reductase-Based Gene Therapy

Despite recent advances, chronic heart failure remains a significant and growing unmet medical need, reaching epidemic proportions carrying substantial morbidity, mortality, and costs. A safe and convenient therapeutic agent that produces sustained inotropic effects could ameliorate symptoms and improve functional capacity and quality of life. The authors discovered that small amounts of 2-deoxy-ATP (dATP) activate cardiac myosin leading to enhanced contractility in normal and failing heart muscle. Cardiac myosin activation triggers faster myosin cross-bridge cycling with greater force generation during each contraction. They describe the rationale and results of a translational medicine effort to increase dATP levels using a gene therapy strategy that up-regulates ribonucleotide reductase, the rate-limiting enzyme for dATP synthesis, selectively in cardiomyocytes. In small and large animal models of heart failure, a single dose of this gene therapy has led to sustained inotropic effects with no toxicity or safety concerns identified to date. Further animal studies are being conducted with the goal of testing this agent in patients with heart failure.

Current treatment of heart failure with reduction of left ventricular ejection fraction

Heart failure is the commonest cause of hospitalization and of rehospitalization This review paper is a comprehensive review of current treatment of heart failure in 2016. The target of this review is all health care professionals who treat patients with heart failure. Areas covered: This article discusses stages of heart failure, treatment of heart failure with general measures, and drug therapy with diuretics, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, beta blockers, aldosterone antagonists, isosorbide dinitrate plus hydralazine, digoxin, other neurohormonal antagonists, sacubitril/valsartan, calcium channel blockers, and ivabradine. This article also discusses treatment of heart failure with use of cardiac resynchronization therapy, implantable cardioverter-defibrillators, and surgical therapy, and management of end-stage heart failure. This paper was written after an extensive Medline search reviewing articles written from 1970 through May, 2016. Expert commentary: Our approach as physicians must emphasize prevention of heart failure as well as treating it. Risk factors for developing heart failure, especially hypertension, must be better controlled starting in childhood. I concur with the current heart failure treatment guidelines (Tables 1 and 2 in this paper).

Update of treatment of heart failure with reduction of left ventricular ejection fraction

Underlying and precipitating causes of heart failure (HF) with reduced left ventricular ejection fraction (HFrEF) should be identified and treated when possible. Hypertension should be treated with diuretics, angiotensin-converting enzyme (ACE) inhibitors, and β-blockers. Diuretics are the first-line drugs in the treatment of patients with HFrEF and volume overload. Angiotensin-converting enzyme inhibitors and β-blockers (carvedilol, sustained-release metoprolol succinate, or bisoprolol) should be used in treatment of HFrEF. Use an angiotensin II receptor blocker (ARB) (candesartan or valsartan) if intolerant to ACE inhibitors because of cough or angioneurotic edema. Sacubitril/valsartan may be used instead of an ACE inhibitor or ARB in patients with chronic symptomatic HFrEF class II or III to further reduce morbidity and mortality. Add an aldosterone antagonist (spironolactone or eplerenone) in selected patients with class II-IV HF who can be carefully monitored for renal function and potassium concentration. (Serum creatinine should be ≤ 2.5 mg/dl in men and ≤ 2.0 mg/dl in women. Serum potassium should be < 5.0 mEq/l). Add isosorbide dinitrate plus hydralazine in patients self-described as African Americans with class II-IV HF being treated with diuretics, ACE inhibitors, and β-blockers. Ivabradine can be used in selected patients with HFrEF.

Quality of life and long-term mortality in patients with advanced chronic heart failure treated with intermittent low-dose intravenous inotropes in an outpatient setting

AIMS

There are limited data on the effect of low-dose, intermittent inotropic therapy in an outpatient setting on the quality of life (QOL) in patients with advanced refractory heart failure (HF) symptoms. We aimed to analyse the effect of this treatment modality on QOL and subsequent survival.

METHODS AND RESULTS

The study population comprised 287 consecutive patients with advanced refractory HF symptoms who were treated with low-dose, intravenous intermittent inotropic therapy in the HF Day Care Service at Sheba Medical Centre between September 2000 and September 2012. All patients completed a baseline Minnesota Living with Heart Failure Questionnaire (MLWHFQ), and 137 (48%) completed a 1 year follow-up questionnaire. MLWHFQ scores' means ranged from 0 (better QOL) to 5 (worse QOL). Mean age was 68 ± 12, 86% were men, 77% had ischaemic cardiomyopathy, and the mean left ventricle ejection fraction (LVEF) was 26% ± 13. The mean baseline MLWHFQ score was 3.1 (±1), while the mean at 1 year of treatment was of 2.7 (±1.1), indicating an overall improvement in QOL associated with intermittent low-dose inotrope therapy (p < 0.01). Multivariate analysis showed that younger age, non-ischaemic cardiomyopathy, and worse renal function were independently associated with improvement in QOL at 1 year. Improvement in QOL was not associated with a significant survival benefit during subsequent follow-up.

CONCLUSIONS

In patients with advanced refractory HF symptoms, treatment with low-dose, intermittent intravenous inotropes in an outpatient setting is associated with significant improvement in QOL. However, improvement in QOL in this population does not appear to affect subsequent long-term survival.

Quality of life assessment in heart failure interventions: a 10-year (1996–2005) review

The increasing prevalence and poor prognosis associated with heart failure have prompted research to focus on improving quality of life (QoL) for heart failure patients. Research from 1996–2005 was systematically reviewed to identify randomized controlled trials that assessed QoL in heart failure. In 120 studies, 44 were medication trials; 19 surgical/procedural interventions; and 57 patient care/service delivery interventions. Studies were summarized in terms of aim, population, QoL measures used and QoL findings. Studies used 47 different measures of QoL-generic, health-related, condition-specific, domain-specific and utility measures. Most used a single QoL measure. In 87%, a condition specific QoL measure was used, with the Minnesota Living with Heart Failure Questionnaire being the favoured assessment tool. The range of QoL measures in use poses challenges for development of cumulative knowledge. Although comparability across studies is important, this must be informed by the responsiveness of the instrument selected. As carried out in other cardiac groups, comparative evaluations of instrument responsiveness are needed in heart failure. Eur J Cardiovasc Prev Rehabil 14:589-607 © 2007 The European Society of Cardiology

Omecamtiv Mecarbil, a Cardiac Myosin Activator, Increases Ca2+ Sensitivity in Myofilaments With a Dilated Cardiomyopathy Mutant Tropomyosin E54K

Apart from transplant, there are no satisfactory therapies for the severe depression in contractility in familial dilated cardiomyopathy (DCM). Current heart failure treatments that act by increasing contractility involve signaling cascades that alter calcium homeostasis and induce arrhythmias. Omecamtiv mecarbil is a promising new inotropic agent developed for heart failure that may circumvent such limitations. Omecamtiv is a direct cardiac myosin activator that promotes and prolongs the strong myosin-actin binding conformation to increase the duration of systolic elastance. We tested the effect of omecamtiv on Ca(2+) sensitivity of myofilaments of a DCM mouse model containing a tropomyosin E54K mutation. We compared tension and ATPase activity of detergent-extracted myofilaments with and without treatment with 316 nM omecamtiv at varying pCa values. When transgenic myofilaments were treated with omecamtiv, the pCa50 for activation of tension increased from 5.70 ± 0.02 to 5.82 ± 0.02 and ATPase activity increased from 5.73 ± 0.06 to 6.07 ± 0.04. This significant leftward shift restored Ca(2+) sensitivity to levels no longer significantly different from controls. Proteomic studies lacked changes in sarcomeric protein phosphorylation. Our data demonstrate that omecamtiv can potentially augment cardiac contractility in DCM by increasing Ca(2+) sensitivity. The use of direct myosin activators addresses functional defects without incurring the adverse side effects of Ca(2+)-dependent treatments.

Futility approaches to interim monitoring by data monitoring committees

Clinical trials involving participants with high risk of serious events or being exposed to a new intervention with potential serious risk are typically monitored during the course of the trial. Often, this monitoring activity is conducted by an independent group of experts, often referred to as a Data Monitoring Committee (DMC). The DMC responsibility includes monitoring for early evidence of a harmful effect or convincing evidence of a benefit. If the data are consistent and overwhelming, the DMC may recommend that a trial be terminated early. Trials may also be terminated early if the initial goal of demonstrating a benefit cannot in all likelihood be attained, or is futile. These are complicated issues and should be sorted out in the protocol and the DMC charter prior to the start of the trial before data begin to accumulate. Several statistical methods have been developed to assist a DMC in determining when a negative or harmful trend is substantial enough to render the trial continuation futile. These will be briefly summarized. However useful these methods might be, they alone are not adequate to make the decision and the DMC must take into account other issues to make a judgment.

Statistical Methods for Cardiovascular Researchers

RATIONALE

Biostatistics continues to play an essential role in contemporary cardiovascular investigations, but successful implementation of biostatistical methods can be complex.

OBJECTIVE

To present the rationale behind statistical applications and to review useful tools for cardiology research.

METHODS AND RESULTS

Prospective declaration of the research question, clear methodology, and study execution that adheres to the protocol together and serve as the critical foundation of a research endeavor. Both parametric and distribution-free measures of central tendency and dispersion are presented. T testing, ANOVA, and regression analyses are reviewed. Survival analysis, logistic regression, and interim monitoring are also discussed. Finally, common weaknesses in statistical analyses are considered.

CONCLUSIONS

Biostatistics can be productively applied to cardiovascular research if investigators (1) develop and rely on a well-written protocol and analysis plan, (2) consult with a biostatistician when necessary, and (3) write results clearly, differentiating confirmatory from exploratory findings.

Falling Cardiovascular Mortality in Heart Failure With Reduced Ejection Fraction and Implications for Clinical Trials

OBJECTIVES

This study examined the trends in the relative contributions of cardiovascular and noncardiovascular mortality to total mortality according to use of beta-blockers in clinical trials of patients with heart failure with reduced ejection fraction (HF-REF).

BACKGROUND

With the increasingly widespread use of disease-modifying therapies, particularly beta-blockers, in HF-REF, the proportion of patients dying from cardiovascular causes is likely to be decreasing.

METHODS

In a systematic review, 2 investigators independently searched online databases to identify clinical trials including >400 patients with chronic heart failure published between 1986 and 2014 and that adjudicated cause of death. Trials were divided into 3 groups on the basis of the proportion of patients treated with a beta-blocker (<33% [low], 33% to 66% [medium], and >66% [high]). Percentages of total deaths adjudicated as cardiovascular or noncardiovascular were calculated by weighted means and weighted standard deviations. Weighted Student t tests were used to compare results between groups.

RESULTS

Sixty-six trials met the inclusion criteria with a total of 136,182 patients and 32,140 deaths. There was a sequential increase in the percentage of noncardiovascular deaths with increasing beta-blocker use from 11.4% of all deaths in trials with low beta-blocker use to 19.1% in those with high beta-blocker use (p < 0.001).

CONCLUSIONS

In trials of patients with HF-REF, the proportion of deaths adjudicated as cardiovascular has decreased. Cardiovascular mortality, and not all-cause mortality, should be used as an endpoint for trials of new treatments for HF-REF.

The Effect of Cilostazol on Endothelial Function as Assessed by Flow-Mediated Dilation in Patients with Coronary Artery Disease

Aim: The vascular endothelium plays a key role in the pathophysiology of atherosclerosis. Flow-mediated dilation (FMD) is a novel way of assessing endothelial function. Cilostazol is a unique antiplatelet drug that also has the potential to improve endothelial function. The objective of this present study was to investigate the effects of cilosatzol on endothelial function as assessed by FMD.

Methods: Fifty-one patients with coronary artery disease (CAD) were assigned to one of two groups: the Cilostazol(+) group (with cilostazol) and Cilostazol(−) group (without cilostazol). In addition to conventional dual antiplatelet therapy with aspirin and clopidogrel/ticlopidine, the Cilostazol(+) group (n = 27) was also given cilostazol (100 mg/day). The Cilostazol(−) group (n = 24) did not receive cilostazol. FMD was assessed at enrollment and after 6–9 months.

Results: The FMD of both the Cilostazol(+) and Cilostazol(−) groups remained similar at 5.2 (interquartile range: 3.8–8.5) to 5.4 (interquartile range: 4.2–6.7) (P = 0.29) and 5.0 (interquartile range: 3.6–6.4) to 4.9 (interquartile range: 4.0–7.0) (P = 0.38), respectively. However, the diameters of the baseline and maximal brachial arteries tended to increase in the Cilostazol(−) group (baseline: 4.2 ± 0.7 to 4.4 ± 0.7, P = 0.18; maximal: 4.5 ± 0.7 to 4.6 ± 0.7 P = 0.22), whereas that of the Cilostazol(−) group tended to decrease (baseline: 4.1 ± 0.6 to 3.9 ± 0.5, P = 0.10; maximal: 4.3 ± 0.7 to 4.1 ± 0.5, P = 0.05). The rates of change in the baseline diameter (Cilostazol(+): 3.7 ± 9.8% vs. Cilostazol(−): −3.8 ± 12.2%, P = 0.03) and maximal diameter (Cilostazol(+): +3.1 ± 8.9% vs. Cilostazol(−): −4.4 ± 12.0%, P = 0.02) were significantly different.

Conclusion: Although cilostazol didn't affect the FMD, there was a significant difference in the rates of change in baseline and maximal brachial artery diameter. This may have a beneficial effect in patients with cardiovascular disease.

Novel approaches to targeting PDE3 in cardiovascular disease

Inhibitors of PDE3, a family of dual-specificity cyclic nucleotide phosphodiesterases, are used clinically to increase cardiac contractility by raising intracellular cAMP content in cardiac myocytes and to reduce vascular resistance by increasing intracellular cGMP content in vascular smooth muscle myocytes. When used in the treatment of patients with heart failure, PDE3 inhibitors are effective in the acute setting but increase sudden cardiac death with long-term administration, possibly reflecting pro-apoptotic and pro-hypertrophic consequences of increased cAMP-mediated signaling in cardiac myocytes. cAMP-mediated signaling in cardiac myocytes is highly compartmentalized, and different phosphodiesterases, by controlling cAMP content in functionally discrete intracellular microcompartments, regulate different cAMP-mediated pathways. Four variants/isoforms of PDE3 (PDE3A1, PDE3A2, PDE3A3, and PDE3B) are expressed in cardiac myocytes, and new experimental results have demonstrated that these isoforms, which are differentially localized intracellularly through unique protein-protein interactions, control different physiologic responses. While the catalytic regions of these isoforms may be too similar to allow the catalytic activity of each isoform to be selectively inhibited, targeting their unique protein-protein interactions may allow desired responses to be elicited without the adverse consequences that limit the usefulness of existing PDE3 inhibitors.

Team-Based Care for Outpatients with Heart Failure

Management of heart failure requires a multidisciplinary team-based approach that includes coordination of numerous team members to ensure guideline-directed optimization of medical therapy, frequent and regular assessment of volume status, frequent education, use of cardiac rehabilitation, continued assessment for the use of advanced therapies, and advance care planning. All of these are important aspects of the management of this complex condition.

Designing phase 3 sepsis trials: application of learned experiences from critical care trials in acute heart failure

Substantial attention and resources have been directed to improving outcomes of patients with critical illnesses, in particular sepsis, but all recent clinical trials testing various interventions or strategies have failed to detect a robust benefit on mortality. Acute heart failure is also a critical illness, and although the underlying etiologies differ, acute heart failure and sepsis are critical care illnesses that have a high mortality in which clinical trials have been difficult to conduct and have not yielded effective treatments. Both conditions represent a syndrome that is often difficult to define with a wide variation in patient characteristics, presentation, and standard management across institutions. Referring to past experiences and lessons learned in acute heart failure may be informative and help frame research in the area of sepsis. Academic heart failure investigators and industry have worked closely with regulators for many years to transition acute heart failure trials away from relying on dyspnea assessments and all-cause mortality as the primary measures of efficacy, and recent trials have been designed to assess novel clinical composite endpoints assessing organ dysfunction and mortality while still assessing all-cause mortality as a separate measure of safety. Applying the lessons learned in acute heart failure trials to severe sepsis and septic shock trials might be useful to advance the field. Novel endpoints beyond all-cause mortality should be considered for future sepsis trials.

Calmodulin kinase II inhibition limits the pro-arrhythmic Ca2+ waves induced by cAMP-phosphodiesterase inhibitors

AIMS

A major concern of using phosphodiesterase (PDE) inhibitors in heart failure is their potential to increase mortality by inducing arrhythmias. By diminishing cyclic adenosine monophosphate (cAMP) hydrolysis, they promote protein kinase A (PKA) activity under β-adrenergic receptor (β-AR) stimulation, hence enhancing Ca(2+) cycling and contraction. Yet, cAMP also activates CaMKII via PKA or the exchange protein Epac, but it remains unknown whether these pathways are involved in the pro-arrhythmic effect of PDE inhibitors.

METHODS AND RESULTS

Excitation-contraction coupling was investigated in isolated adult rat ventricular myocytes loaded with Fura-2 and paced at 1 Hz allowing coincident measurement of intracellular Ca(2+) and sarcomere shortening. The PDE4 inhibitor Ro 20-1724 (Ro) promoted the inotropic effects of the non-selective β-AR agonist isoprenaline (Iso) and also spontaneous diastolic Ca(2+) waves (SCWs). PDE4 inhibition potentiated RyR2 and PLB phosphorylation at specific PKA and CaMKII sites increasing sarcoplasmic reticulum (SR) Ca(2+) load and SR Ca(2+) leak measured in a 0Na(+)/0Ca(2+) solution ± tetracaine. PKA inhibition suppressed all the effects of Iso ± Ro, whereas CaMKII inhibition prevented SR Ca(2+) leak and diminished SCW incidence without affecting the inotropic effects of Ro. Inhibition of Epac2 but not Epac1 diminished the occurrence of SCWs. PDE3 inhibition with cilostamide induced an SR Ca(2+) leak, which was also blocked by CaMKII inhibition.

CONCLUSION

Our results show that PDE inhibitors exert inotropic effects via PKA but lead to SCWs via both PKA and CaMKII activation partly via Epac2, suggesting the potential use of CaMKII inhibitors as adjuncts to PDE inhibition to limit their pro-arrhythmic effects.

Current and Potential Therapeutic Strategies for Hemodynamic Cardiorenal Syndrome

BACKGROUND

Cardiorenal syndrome (CRS) encompasses conditions in which cardiac and renal disorders co-exist and are pathophysiologically related. The newest classification of CRS into seven etiologically and clinically distinct types for direct patient management purposes includes hemodynamic, uremic, vascular, neurohumoral, anemia- and/or iron metabolism-related, mineral metabolism-related and protein-energy wasting-related CRS. This classification also emphasizes the pathophysiologic pathways. The leading CRS category remains hemodynamic CRS, which is the most commonly encountered type in patient care settings and in which acute or chronic heart failure leads to renal impairment.

SUMMARY

This review focuses on selected therapeutic strategies for the clinical management of hemodynamic CRS. This is often characterized by an exceptionally high ratio of serum urea to creatinine concentrations. Loop diuretics, positive inotropic agents including dopamine and dobutamine, vasopressin antagonists including vasopressin receptor antagonists such as tolvaptan, nesiritide and angiotensin-neprilysin inhibitors are among the pharmacologic agents used. Additional therapies include ultrafiltration (UF) via hemofiltration or dialysis. The beneficial versus unfavorable effects of these therapies on cardiac decongestion versus renal blood flow may act in opposite directions. Some of the most interesting options for the outpatient setting that deserve revisiting include portable continuous dobutamine infusion, peritoneal dialysis and outpatient UF via hemodialysis or hemofiltration.

KEY MESSAGES

The new clinically oriented CRS classification system is helpful in identifying therapeutic targets and offers a systematic approach to an optimal management algorithm with better understanding of etiologies. Most interventions including UF have not shown a favorable impact on outcomes. Outpatient portable dobutamine infusion is underutilized and not well studied. Revisiting traditional and novel strategies for outpatient management of CRS warrants clinical trials.

Personalized Cardiovascular Medicine Today: A Food and Drug Administration/Center for Drug Evaluation and Research Perspective

Over the past decade, personalized medicine has received considerable attention from researchers, drug developers, and regulatory agencies. Personalized medicine includes identifying patients most likely to benefit and those most likely to experience adverse reactions in response to a drug, and tailoring therapy based on pharmacokinetics or pharmacodynamic response, as well. Perhaps most exciting is finding ways to identify likely responders through genetic, proteomic, or other tests, so that only likely responders will be treated. However, less precise methods such as identifying historical, demographic, or other indicators of increased or reduced responsiveness are also important aspects of personalized medicine. The cardiovascular field has not used many genetic or proteomic markers, but has regularly used prognostic variables to identify likely responders. The development of biomarker-based approaches to personalized medicine in cardiovascular disease has been challenging, in part, because most cardiovascular therapies treat acquired syndromes, such as acute coronary syndrome and heart failure, which develop over many decades and represent the end result of several pathophysiological mechanisms. More precise disease classification and greater understanding of individual variations in disease pathology could drive the development of targeted therapeutics. Success in designing clinical trials for personalized medicine will require the selection of patient populations with attributes that can be targeted or that predict outcome, and the use of appropriate enrichment strategies once such attributes are identified. Here, we describe examples of personalized medicine in cardiovascular disease, discuss its impact on clinical trial design, and provide insight into the future of personalized cardiovascular medicine from a regulatory perspective.

The Effect of inotropes and vasopressors on mortality: a meta-analysis of randomized clinical trials

BACKGROUND

Inotropes and vasopressors are frequently administered to critically ill patients in order to improve haemodynamic function and restore adequate organ perfusion. However, some studies have suggested a possible association between inotrope administration and increased mortality. We therefore performed a meta-analysis of randomized trials published in the last 20 yr to investigate the effect of these drugs on mortality.

METHODS

BioMedCentral, PubMed, Embase and the Cochrane Central Register were searched (all updated April 8th, 2015). Inclusion criteria were: random allocation to treatment, at least one group receiving an inotropic or vasopressor drug compared with at least one group receiving a non-inotropic/vasopressor treatment, study published after 1st January 1994, and systemic drug administration. Exclusion criteria were overlapping populations, studies published as abstract only, crossover studies, paediatric studies and lack of data on mortality.

RESULTS

A total of 28 280 patients from 177 trials were included. Overall, pooled estimates showed no difference in mortality between the group receiving inotropes/vasopressors and the control group [4255/14 036 (31.7%) vs. 4277/14 244 (31.8%), risk ratio=0.98 (0.96-1.01), P for effect=0.23, P for heterogeneity=0.30, I2=6%]. A reduction in mortality was associated with inotrope/vasopressor therapy use in settings of vasoplegic syndromes, sepsis and cardiac surgery. Levosimendan was the only drug associated with improvement in survival. Subgroup analysis did not identify any groups with increased mortality associated with inotrope/vasopressor therapy.

CONCLUSIONS

Our systematic review found that inotrope/vasopressor therapy is not associated with differences in mortality in the overall population and in the majority of subsettings.

What can we do about exploratory analyses in clinical trials?

The research community has alternatively embraced then repudiated exploratory analyses since the inception of clinical trials in the middle of the twentieth century. After a series of important but ultimately unreproducible findings, these non-prospectively declared evaluations were relegated to hypothesis generating. Since the majority of evaluations conducted in clinical trials with their rich data sets are exploratory, the absence of their persuasive power adds to the inefficiency of clinical trial analyses in an atmosphere of fiscal frugality. However, the principle argument against exploratory analyses is not based in statistical theory, but pragmatism and observation. The absence of any theoretical treatment of exploratory analyses postpones the day when their statistical weaknesses might be repaired. Here, we introduce examination of the characteristics of exploratory analyses from a probabilistic and statistical framework. Setting the obvious logistical concerns aside (i.e., the absence of planning produces poor precision), exploratory analyses do not appear to suffer from estimation theory weaknesses. The problem appears to be a difficulty in what is actually reported as the p-value. The use of Bayes Theorem provides p-values that are more in line with confirmatory analyses. This development may inaugurate a body of work that would lead to the readmission of exploratory analyses to a position of persuasive power in clinical trials.

Digoxin Use and Subsequent Outcomes Among Patients in a Contemporary Atrial Fibrillation Cohort

BACKGROUND

Although digoxin has long been used to treat atrial fibrillation (AF) and heart failure (HF), its safety remains controversial.

OBJECTIVES

This study sought to describe digoxin use over time in patients with AF who were stratified by the presence or absence of HF, to characterize the predictors of digoxin use and initiation, and to correlate digoxin use with outcomes.

METHODS

Longitudinal patterns of digoxin use and its association with a variety of outcomes were assessed in a prospective outpatient registry conducted at 174 U.S. sites with enrollment from June 2010 to August 2011.

RESULTS

Among 9,619 patients with AF and serial follow-up every 6 months for up to 3 years, 2,267 (23.6%) received digoxin at study enrollment, 681 (7.1%) were initiated on digoxin during follow-up, and 6,671 (69.4%) were never prescribed digoxin. After adjusting for other medications, heart rate was 72.9 beats/min among digoxin users and 71.5 beats/min among nonusers (p < 0.0001). Prevalent digoxin use at registry enrollment was not associated with subsequent onset of symptoms, hospitalization, or mortality (in patients with HF, adjusted hazard ratio [HR] for death: 1.04; without HF, HR: 1.22). Incident digoxin use during follow-up was not associated with subsequent death in patients with HF (propensity adjusted HR: 1.05), but was associated with subsequent death in those without HF (propensity adjusted HR: 1.99).

CONCLUSIONS

After adjustment for detailed clinical factors, digoxin use in registry patients with AF had a neutral association with outcomes under most circumstances. Because of the multiple conflicting observational reports about digoxin's safety and possible concerns in specific clinical situations, a large pragmatic trial of digoxin therapy in AF is needed.

Clinical Characteristics and Outcomes of Intravenous Inotropic Therapy in Advanced Heart Failure

BACKGROUND

Inotrope use in heart failure treatment was associated with improved symptoms, but worse survival in clinical trials. However, these studies predated use of modern heart failure therapies. This study evaluates contemporary outcomes on long-term inotropes.

METHODS AND RESULTS

We collected baseline and postinotrope data on 197 patients discharged on inotropes between January 2007 and March 2013. Baseline characteristics, hemodynamic and clinical changes on inotropes, and survival were evaluated. Patients initiated on inotropes had refractory heart failure, with median baseline New York Heart Association class IV, cardiac index of 1.7 L/min per m(2), pulmonary capillary wedge pressure of 25.6 mm Hg, and left ventricular ejection fraction of 18.7%. Inotropes were used in patients listed for transplant or scheduled for left ventricular assist device (LVAD; 60 patients), in patients being evaluated for LVAD/transplant (20 patients), for stabilization pending cardiac resynchronization therapy/percutaneous coronary intervention (4 patients), in patients who were offered LVAD but chose inotropes (15 patients), and for palliation (98 patients). Milrinone was used in 84.8% and dobutamine in 15.2%. At the end of the study, 68 patients had died, 24 were weaned off inotropes, 23 were transplanted, 32 received LVADs, and 50 remained on inotropes. Patients who received inotropes for palliation or those who preferred inotropes over LVAD had median survival of 9.0 months (interquartile range, 3.1-37.1 months), actuarial 1-year survival of 47.6%, and 2-year survival of 38.4%. Of 60 patients who were placed on inotropes as a bridge to transplant/LVAD, 55 were successfully maintained on inotropes until transplant/LVAD.

CONCLUSIONS

Survival on inotropes for patients who are not candidates for transplant/LVAD is modestly better than previously reported, but remains poor. Inotropes are effective as a bridge to transplant/LVAD.

Population pharmacokinetic-pharmacodynamic modeling of omecamtiv mecarbil, a cardiac myosin activator, in healthy volunteers and patients with stable heart failure

Data from 3 clinical trials of omecamtiv mecarbil in healthy volunteers and patients with stable heart failure (HF) were analyzed using a nonlinear mixed-effects model to investigate omecamtiv mecarbil's pharmacokinetics and relationship between plasma concentration and systolic ejection time (SET) and Doppler-derived left ventricular outflow tract stroke volume (LVOTSV). Omecamtiv mecarbil pharmacokinetics were described by a linear 2-compartment model with a zero-order input rate for intravenous administration and first-order absorption for oral administration. Oral absorption half-life was 0.62 hours, and absolute bioavailability was estimated as 90%; elimination half-life was approximately 18.5 hours. Variability in pharmacokinetic parameters was not explained by patient baseline characteristics. Omecamtiv mecarbil plasma concentration was directly correlated with increases in SET and LVOTSV between healthy volunteers and patients with HF. The maximum increase from baseline in SET (delta SET) estimated by an Emax model was 137 milliseconds. LVOTSV increased linearly from baseline by 1.6 mL per 100 ng/mL of omecamtiv mecarbil. Model-based simulations for several immediate-release oral dose regimens (37.5, 50, and 62.5 mg dosed every 8, 12, and 24 hours) showed that a pharmacodynamic effect (delta SET ≥20 milliseconds) could be maintained in the absence of excessive omecamtiv mecarbil plasma concentrations.