Anti-ischemic effects and long-term survival during ranolazine monotherapy in patients with chronic severe angina

Electrical plasticity and cardioprotection in myocardial ischemia--role of selective sodium channel blockers

The concept of electrical protection of the ischemic myocardium is in constant evolution and has recently been supported by experimental and clinical studies. Historically, antiplatelet agents, angiotensin-converting enzyme inhibitors, β-blockers, and statins have been all proposed as drugs conferring anti-ischemic cardioprotection. This was supported by the evidence consistently indicating that all these drugs were capable of reducing mortality and the risk of repeat myocardial infarction. The electrical plasticity paradigm is, however, a novel concept that depicts the benefits of improved sodium channel blockade with drugs such as ranolazine and cariporide. Although it has been hypothesized that the protective role of ranolazine depends on decreased fatty acid β-oxidation affecting preconditioning, we speculate against such a hypothesis, because inhibition of β-oxidation requires higher concentrations of the drug, above the therapeutic range. Rather, we discuss the key role of calcium overload reduction through inhibition of the late sodium current (I(Na)). Mechanisms driving cardioprotection involve the block of a cascade of complex ionic exchanges that can result in intracellular acidosis, excess cytosolic calcium, myocardial cellular dysfunction, and eventually cell injury and death. In this review we discuss the studies that demonstrate how electrical plasticity through sodium channel blockers can promote cardioprotection against ischemia in coronary heart disease.

Ranolazine: clinical applications and therapeutic basis

Ranolazine is currently approved for use in chronic angina. The basis for this use is likely related to inhibition of late sodium channels with resultant beneficial downstream effects. Randomized clinical trials have demonstrated an improvement in exercise capacity and reduction in angina episodes with ranolazine. This therapeutic benefit occurs without the hemodynamic effects seen with the conventional antianginal agents. The inhibition of late sodium channels as well as other ion currents has a central role in the potential use of ranolazine in ischemic heart disease, arrhythmias, and heart failure. Despite its QTc-prolonging action, albeit minimal, clinical data have not shown a predisposition to torsades de pointes, and the medication has shown a reasonable safety profile even in those with structural heart disease. In this article we present the experimental and clinical data that support its current therapeutic role, and provide insight into potential future clinical applications.

Tolerability and pharmacokinetics of ranolazine following single and multiple sustained-release doses in Chinese healthy adult volunteers: a randomized, open-label, Latin square design, phase I study

BACKGROUND AND OBJECTIVES

Ranolazine was approved by the US Food and Drug Administration in January 2006 for the treatment of chronic angina pectoris, and is the first approved agent from a new class of anti-anginal drugs in almost 25 years. The primary objective of this study was to determine the concentration of ranolazine in human plasma using the liquid chromatography/tandem mass spectrometry (LC-MS/MS) method and to compare the pharmacokinetic properties of ranolazine after administration of single and multiple doses of ranolazine in healthy Chinese adult volunteers.

METHODS

A randomized, open-label, single- and multiple-dose study design was used in the study. Subjects were randomized to receive a single dose of 500, 1,000, or 1,500 mg of ranolazine. Those who received the single dose continued on to the multiple-dose phase and received 500 mg twice daily for 7 days. In the single-dose phase, blood samples were collected from 0 to 48 h after drug administration. In the multiple-dose phase, samples were obtained before drug administration at 8:00 am and 8:00 pm on days 6 and 7 to determine the minimum steady-state plasma concentration (C(min,ss)) of ranolazine; on day 8, samples were collected from 0 to 48 h after drug administration. All values were expressed as means (standard deviations [SDs]). Adverse events (AEs) were monitored throughout the study via subject interview, vital signs, and blood sampling.

RESULTS

The LC-MS/MS method was developed and validated. Twelve Chinese subjects (six men, six women) were enrolled in the single-dose phase of the pharmacokinetic study. The mean (SD) age of the subjects was 24.7 (1.6) years; their mean (SD) weight was 61.3 (6.4) kg, their mean (SD) height was 165.7 (4.5) cm, and their mean (SD) body mass index was 21.6 (6.6) kg/m(2). The main pharmacokinetic parameters [mean (SD)] for ranolazine after administration of a single oral dose of 500, 1,000, and 1,500 mg were as follows: maximum plasma concentration (C(max)) 741.5 (253.0), 1,355.0 (502.0), and 2,328.7 (890.5) ng/mL, respectively; area under the concentration-time curve from time zero to 48 h (AUC(48)) 9,071.9 (3,400.0), 16,573.5 (6,806.2), and 29,324.5 (10,857.2) ng·h/mL; AUC from time zero extrapolated to infinity (AUC(∞)) 9,826.7 (3,152.0), 16,882.4 (6,790.8), and 29,923.5 (10,706.3) ng·h/mL; time to reach C(max) (t(max)) 5.3 (1.4), 4.2 (1.2), and 5.9 (2.8) h; elimination half-life (t(½)) 6.4 (3.3), 6.4 (3.5), and 6.7 (4.3) h. Mean (SD) values for the main pharmacokinetic parameters for ranolazine after administration of multiple doses were as follows: steady-state C(max) (C(max,ss)) 1,732.9 (547.3) ng/mL; C(min,ss) 838.1 (429.8) ng/mL; steady-state AUC at time t (AUC(ss,(t))) 14,655.5 (5,624.2) ng·h/mL; average steady-state plasma drug concentration during multiple-dose administration (C(av,ss)) 1,221.3 (468.7) ng/mL; t(max) 3.46 (1.48) h; t(½) 6.28 (2.48) h.

CONCLUSION

In this group of healthy Chinese subjects, AUC and C(max) increased proportionally with the dose, whereas t(½) was independent of the dose. The pharmacokinetic properties of ranolazine were linear after administration of single oral doses of 500 to 1,500 mg. Compared with the pharmacokinetic parameters of the subjects who received a single dose, those who received multiple doses (twice daily) of ranolazine had a larger AUC from time zero to the time of the last measurable concentration (AUC(last)), AUC(∞), C(max), and apparent total body clearance of drug from plasma after oral administration (CL/F), and shorter t(max) (all p < 0.05). Furthermore, some of the main pharmacokinetic parameters of ranolazine may reflect ethnic differences. This dosage was generally well tolerated by all the subjects.

Pharmacological treatment of chronic stable angina pectoris

Chronic stable angina is the most common manifestation of ischaemic heart disease in the developed world and is associated with impaired quality of life and increased mortality. The pathogenesis of stable angina is complex and often, albeit not always, involves flow-limiting epicardial coronary artery stenoses (atheromatous plaques) that reduce the ability of the coronary circulation to deliver appropriate blood supply to the myocardium. The coronary microcirculation can also play an important role. An imbalance between myocardial oxygen supply and metabolic oxygen demand causes the symptoms of angina pectoris and represents a major therapeutic target. Rational treatment requires a multi-faceted approach combining lifestyle changes, aggressive management of modifiable coronary artery disease risk factors, pharmacological therapy and myocardial revascularisation when appropriate. Despite modern therapies, many patients continue to suffer from angina. Several new anti-anginal drugs have been introduced that might allow more effective symptom control. These novel agents have specific mechanisms of action and fewer side effects compared to conventional drugs. The combined use of traditional and novel treatments is likely to increase the proportion of patients who are managed successfully with medical therapy alone. This article briefly reviews recent advances in the pharmacological management of chronic stable angina pectoris, highlighting how an understanding of the prevailing pathogenic mechanisms in the individual patient can aid appropriate selection of therapeutic strategies and improve clinical outcome.

Safety and Efficacy of Ranolazine for the Treatment of Chronic Angina Pectoris

Coronary heart disease is a global malady and it is the leading cause of death in the United States. Chronic stable angina is the most common manifestation of coronary heart disease and it results from the imbalance between myocardial oxygen supply and demand due to reduction in coronary blood flow. Therefore, in addition to lifestyle changes, commonly used pharmaceutical treatments for angina (nitrates, β-blockers, Ca2+ channel blockers) are aimed at increasing blood flow or decreasing O2 demand. However, patients may continue to experience symptoms of angina. Ranolazine is a relatively new drug with anti-anginal and anti-arrhythmic effects. Its anti-anginal mechanism is not clearly understood but the general consensus is that ranolazine brings about its anti-anginal effects by inhibiting the late Na+ current and the subsequent intracellular Ca2+ accumulation. Recent studies suggest other effects of ranolazine that may explain its anti-anginal and anti-arrhythmic effects. Nonetheless, clinical trials have proven the efficacy of ranolazine in treating chronic angina. It has been shown to be ineffective, however, in treating acute coronary syndrome patients. Ranolazine is a safe drug with minimal side effects. It is metabolized mainly in the liver and cleared by the kidney. Therefore, caution must be taken in patients with impaired hepatic or renal function. Due to its efficacy and safety, ranolazine was approved for the treatment of chronic angina by the Food and Drug Administration (FDA) in 2006.

Neurologic adverse effects of ranolazine in an elderly patient with renal impairment

Ranolazine, an antianginal agent, has activity at muscle and neuronal sodium channels. Congenital genetic mutations to sodium channels in humans and supratherapeutic ranolazine concentrations in animal models have produced similar neurologic adverse reactions. We describe a case of neurologic adverse effects in an 81-year-old woman with coronary artery disease, renal impairment, and mild neurologic disease who received ranolazine for symptomatic control of a non-ST-segment elevation myocardial infarction. Just over 48 hours after a dose increase, she experienced new-onset dysarthia, dysmetria, hallucinations, worse tremors, and difficulty with word finding. Her workup for acute stroke and infectious causes was negative. Her symptoms abated 2 days after ranolazine was discontinued. The patient was at risk for ranolazine adverse effects due to the high dose administered and her advanced age, renal impairment, and baseline mild neurologic disease. Use of the Naranjo adverse drug reaction probability scale indicated a probable relationship (score of 5) between the patient's neurologic adverse events and the ranolazine therapy. To our knowledge, this is the first case report illustrating rare but debilitating neurologic adverse effects of ranolazine. Health care practitioners should be aware of the adverse effects of ranolazine and avoid doses greater than 500 mg twice/day in patients older than 80 years or those with a creatinine clearance of less than 30 ml/minute.

The risk of sudden cardiac death in patients with non-ST elevation acute coronary syndrome and prolonged QTc interval: effect of ranolazine

AIMS

Clinical utility of QTc prolongation as a predictor for sudden cardiac death (SCD) has not been definitely established. Ranolazine causes modest QTc prolongation, yet it shows antiarrhythmic properties. We aimed to determine the association between prolonged QTc and risk of SCD, and the effect of ranolazine on this relationship.

METHODS AND RESULTS

The relationship between baseline QTc and SCD was studied in 6492 patients with non-ST elevation acute coronary syndrome (NSTEACS) randomized to placebo or ranolazine in the MERLIN-TIMI 36 trial. In the placebo group, an abnormal QTc interval (≥450 ms in men, ≥470 ms in women) was associated with a two-fold increased risk of SCD (hazard ratio, HR, 2.3, P = 0.005) after adjustment for other risk factors (age ≥75 years, NYHA class III/IV, high TIMI risk score, ventricular tachycardia ≥8 beats, digitalis, and antiarrhythmics). In the ranolazine group, the association between abnormal QTc and SCD was similar to placebo, but not significant (HR 1.8, P = 0.074). There was no significant difference between placebo and ranolazine in the risk for SCD in patients with abnormal QTc (HR 0.78, P = 0.48). When QTc was used as a continuous variable, for every 10 ms increase in QTc, hazard rate for SCD increased significantly by 8% (P = 0.007) in the placebo group, and only by 2.9% (P = 0.412; P for interaction=0.25) in the ranolazine group.

CONCLUSION

In NSTEACS patients treated with placebo, prolonged QTc was a significant independent predictor for SCD. Ranolazine, compared with placebo, was not associated with increased risk for SCD in patients with prolonged QTc.

Effect of ranolazine on arterial endothelial function in patients with type 2 diabetes mellitus

OBJECTIVE

To assess the effect of ranolazine on systemic vascular function in patients with type II diabetes mellitus (T2DM).

METHODS

We randomized 30 consecutive T2DM patients with no evidence of cardiovascular disease and no insulin therapy to receive one of the following 3 forms of treatment in a blinded fashion: ranolazine, 375 mg bid for 3 weeks (group 1); ranolazine, 375 mg bid for 2 weeks, followed by placebo bid for 1 week (group 2); placebo bid for 3 weeks (group 3). Flow-mediated dilation (FMD) and nitrate-mediated dilation (NMD) of the right brachial artery were assessed at baseline and after 48 h, and 2 and 3 weeks.

RESULTS

FMD and NMD were similar among groups at baseline. Compared to the basal value, FMD significantly improved after 2 weeks in group 1 and in group 2 (p < 0.01 for both), but not in group 3. At 3 weeks, FMD remained improved, compared to baseline, in group 1 (p < 0.05), whereas returned to basal values in group 2 (p = 0.89 vs. baseline). No changes in NMD were observed in any group.

CONCLUSIONS

In this controlled study, ranolazine was able to improve endothelial function in T2DM patients.

New treatment options for late Na current, arrhythmias, and diastolic dysfunction

The late Na current is of pathophysiological importance for the heart. Ranolazine is an innovative anti-ischemic and antianginal agent that inhibits the late Na current, thereby reducing the Na-dependent Ca-overload, which improves diastolic tone and oxygen handling during myocardial ischemia. In addition, ranolazine seems to exert beneficial effects on diastolic cardiac function. Moreover, there are experimental and clinical data about its antiarrhythmic properties. A beneficial atrial selectivity of ranolazine has been suggested that may be helpful for the treatment of atrial fibrillation. The purpose of this review article is to discuss possible future clinical indications based on novel experimental and preclinical results and the significance of the available data.

Ranolazine for the treatment of refractory angina in a veterans population

BACKGROUND

Pivotal ranolazine trials did not require optimization of conventional medical therapy including coronary revascularization and antianginal drug therapy prior to ranolazine use. This case series describes the use of ranolazine for the treatment of chronic stable angina refractory to maximal medical treatment in a veterans population.

RESULTS

A total of 18 patients with a median age of 66 years were identified. All patients had prior percutaneous coronary intervention and/or coronary artery bypass graft surgery; 83% had three-vessel coronary artery disease, with left main disease present in 39% of patients. Prior to initiating ranolazine, antianginal use consisted of beta blockers (94%), long-acting nitrates (83%) and calcium channel blockers (61%). Median blood pressure (116.2/61.8 mmHg) and pulse (65 beats per min) were controlled. Median preranolazine angina episodes and sublingual nitroglycerin (SLNTG) doses per week were 14 and 10, respectively, with a Canadian Cardiovascular Society (CCS) angina grade of III-IV in 67% of patients. After initiation of ranolazine, median angina episodes per week and SLNTG doses used per week decreased to 0.7 and 0, respectively, with CCS grade of III-IV declining to 17%. Of the 18 subjects enrolled, 44% had complete resolution of angina episodes.

CONCLUSION

The addition of ranolazine to maximally tolerated conventional antianginal drug therapy post coronary revascularization was associated with decreases in angina episodes and SLNTG utilization and improvement in CCS angina grades. Ranolazine may provide an effective treatment option for revascularized patients with refractory angina.

A pilot randomized study of ranolazine for reduction of myocardial damage during elective percutaneous coronary intervention

BACKGROUND

Ranolazine is a new antianginal drug that reduces intracellular sodium and calcium accumulation during ischemia, thus potentially limiting myocardial ischemia. It remains unknown, however, if the drug can play a role in the pathophysiology of periprocedural myocardial infarction. The aim of this study was to verify in a randomized study if pretreatment with ranolazine before percutaneous coronary intervention (PCI) has any protective effect on periprocedural myocardial damage.

METHODS

Seventy patients with stable angina (age 62 ± 18 years, 42 men) scheduled for elective coronary intervention entered a randomized, double-blind, placebo-controlled pilot trial. For 7 days before the procedure, 35 patients were assigned to receive ranolazine (1,000 mg twice daily) and 35 patients had placebo. Creatine kinase-MB and troponin I levels were measured at baseline and at 8 and 24 hours postprocedure.

RESULTS

Comparison between the 2 groups did not show any difference in clinical features, extent of coronary artery disease, and technical aspects of PCI. Periprocedural myocardial infarction (ie, postprocedural increase of creatine kinase-MB ≥ 3 times above the upper limit of normal) was less commonly seen after PCI in the ranolazine than in the placebo group (6% vs 22%, P = .041). Detection of markers of myocardial injury above the upper limit of normal was less common [corrected] in the ranolazine vs placebo group: 23% vs 40% for creatine kinase-MB (P = .010) and 31% vs 48% for troponin I (P = .011). [corrected] Postprocedural peak markers levels were also significantly lower in the ranolazine vs placebo group (creatine kinase-MB: 3.1 ± 15.0 and 7.7 ± 19.1 ng/mL, P < .05; troponin I: 0.15 ± 0.35 and 0.47 ± 0.49 ng/mL, P < .05). No significant adverse effect was reported by the 2 groups of patients.

CONCLUSIONS

Pretreatment with ranolazine 1,000 mg twice daily for 7 days significantly reduced procedural myocardial injury in elective PCI.

Stable angina pectoris: the medical management of symptomatic myocardial ischemia

Coronary artery disease (CAD) remains an important cause of morbidity and mortality and is a serious public health problem. Over the last 4 decades there have been dramatic advances in the both the prevention and treatment of CAD. The management of CAD was revolutionized by the development of effective surgical and percutaneous revascularization techniques. In this review we discuss the importance of the medical management of symptomatic, stable angina. Medical management approaches to both the treatment and prevention of symptomatic myocardial ischemia are summarized. In Canada, organic nitrates, β-adrenergic blocking agents, and calcium channel antagonists have been available for the therapy of angina for more than 25 years. All 3 classes are of proven benefit in the improvement of symptoms and exercise capacity in patients with stable angina. Although there is no clear first choice within these classes of anti-anginal agents, the presence of prior or concurrent conditions (for example, prior myocardial infarction and/or hypertension) plays an important role in the choice of anti-anginal class in individual patients. For some patients, combinations of different anti-anginal agents can be effective; however it is recommended that this approach be individualized. Although not currently available in Canada, other classes of anti-anginal agents have been developed; their mechanism of action and clinical efficacy is discussed. Patients with stable angina have an excellent prognosis. Patients in this category who obtain relief from symptomatic myocardial ischemia may do well without invasive intervention.

Treatment strategies for chronic stable angina

INTRODUCTION

Stable angina pectoris - generally the expression of an imbalance between myocardial oxygen demand and supply - is often the first manifestation of ischemic heart disease. The effective management of this highly prevalent condition is largely dependent on the identification of the prevailing pathogenic mechanism, the implementation of lifestyle changes and the appropriate use of pharmacological agents and revascularization techniques. There is abundant literature on management of chronic stable angina, but publications are generally devoted to focused areas. There is a need for a comprehensive review that addresses both the different types of angina and their pathogenic mechanisms, as well as rational approaches to patient management.

AREAS COVERED

This paper reviews the pathogenesis and pathophysiological mechanisms of myocardial ischemia, along with its consequences and current treatment options. Relevant papers in the English literature were identified via PubMed, using the following keywords relating to chronic stable angina: ischemic heart disease, coronary artery disease and antianginal therapy.

EXPERT OPINION

The treatment of chronic stable angina has improved in recent years as a result of a better understanding of its pathogenic mechanisms, the implementation of lifestyle changes and aggressive management of risk factors, as well as pharmacological advances and better revascularization techniques. Understanding the pathogenesis of the disease is important to identify effective treatment strategies. A careful clinical history, the implementation of appropriate diagnostic tests and a rational use of antianginal drugs and revascularization protocols often ensure the successful control of the patient's symptoms.

Effect of ranolazine on rat intrarenal arteries in vitro

Ranolazine is mainly used to treat patients with chronic stable angina in clinical practice. However, ranolazine does not lower significantly systemic blood pressure. The direct effect of ranolazine on vascular tone remains unknown. In the present study, we investigated the vascular effects and mechanisms of action of ranolazine in isolated rat intrarenal arteries. Rings of intrarenal arteries were mounted in a small vessel myography using two stainless steel wires for the measurement of isometric tension. L-type Ca²⁺ currents were recorded in isolated single renal arterial smooth muscle cells using patch clamp techniques in whole-cell mode. Ranolazine induced concentration-dependent relaxations in rings contracted with phenylephrine, but ranolazine failed to cause any relaxation in rings pre-contracted by U46619, 5-HT or endothelin-1. Ranolazine also induced relaxations in norepinephrine pre-contracted rings. Yohimbine failed to induce relaxation in rings pre-contracted by norepinephrine. Propranolol did not affect ranolazine-induced relaxation but the relaxant effect of ranolazine was much less than that of prazosin. Ranolazine-induced relaxations were slight but significantly attenuated by endothelial denudation. Partial inhibition was observed in endothelium-intact arteries exposed to a combination of iberiotoxin and apamin. Ranolazine at higher concentration (>30 μM) inhibited Ca²⁺-induced contraction in a noncompetitive manner. Ranolazine reduced L-type Ca²⁺ currents at potentials between -30 and 50 mV in isolated renal artery myocytes. Therefore it can be said that ranolazine has significant α₁-adrenergic receptor and weak calcium channel antagonistic effects in rat intrarenal arteries.

A double-blind, placebo-controlled, randomized, clinical trial of the TLR-3 agonist rintatolimod in severe cases of chronic fatigue syndrome

Background

Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) is a severely debilitating disease of unknown pathogenesis consisting of a variety of symptoms including severe fatigue. The objective of the study was to examine the efficacy and safety of a TLR-3 agonist, rintatolimod (Poly I: C₁₂U), in patients with debilitating CFS/ME.

Methods and Findings

A Phase III prospective, double-blind, randomized, placebo-controlled trial comparing twice weekly IV rintatolimod versus placebo was conducted in 234 subjects with long-standing, debilitating CFS/ME at 12 sites. The primary endpoint was the intra-patient change from baseline at Week 40 in exercise tolerance (ET). Secondary endpoints included concomitant drug usage, the Karnofsky Performance Score (KPS), Activities of Daily Living (ADL), and Vitality Score (SF 36). Subjects receiving rintatolimod for 40 weeks improved intra-patient placebo-adjusted ET 21.3% (p = 0.047) from baseline in an intention-to-treat analysis. Correction for subjects with reduced dosing compliance increased placebo-adjusted ET improvement to 28% (p = 0.022). The improvement observed represents approximately twice the minimum considered medically significant by regulatory agencies. The rintatolimod cohort vs. placebo also reduced dependence on drugs commonly used by patients in an attempt to alleviate the symptoms of CFS/ME (p = 0.048). Placebo subjects crossed-over to receive rintatolimod demonstrated an intra-patient improvement in ET performance at 24 weeks of 39% (p = 0.04). Rintatolimod at 400 mg twice weekly was generally well-tolerated.

Conclusions/Significance

Rintatolimod produced objective improvement in ET and a reduction in CFS/ME related concomitant medication usage as well as other secondary outcomes.

Trial Registration

ClinicalTrials.gov NCT00215800

[Conservative therapy of patients with stable coronary heart disease]

The main treatment goals of conservative treatment of patients with stable coronary heart disease are prevention of symptoms, prevention of myocardial infarction, and heart failure and reduction of mortality. Lifestyle changes (smoking cessation, physical activity) are essential to reduce risk factors. For symptomatic treatment and prevention of angina pectoris, beta-blockers, calcium channel blockers, nitrates, I((f)) (funny channel) blockers and ranolazine are effective. Cornerstones of pharmacological prevention are drugs with prognostic effects, specifically aspirin and statins, as well as treatment of co-existing disorders such as hypertension and diabetes.

Treatment of stable angina pectoris

Management of stable angina pectoris includes antianginal medications, medications to prevent progression of atherosclerosis, and aggressive treatment of causative risk factors. Antianginal medications commonly used include nitrates, beta-blockers, calcium channel blockers, and ranolazine. Antiplatelet agents, statins, and angiotensin-converting enzyme inhibitors are used in patients with these problems to prevent progression of atherosclerosis and/or premature cardiovascular death. Aggressive risk factor control with diet; exercise; treatment of diabetes, hypertension, and dyslipidemia; and strategies to stop smoking and reduce weight should be a part of treatment strategy in all patients. Patients with stable angina who have symptoms refractory to medical treatment usually require coronary angiography, followed by either percutaneous or surgical revascularization. Recent mechanical techniques for the treatment of refractory angina include transmyocardial laser revascularization, enhanced external counterpulsation, and spinal cord stimulation.

Clinical Experience with Ranolazine in a Veteran Population with Chronic Stable Angina

BACKGROUND:

Efficacy of ranolazine in the treatment of chronic stable angina (CSA) has been established; however, pivotal trials did not require the optimization of conventional antianginal drug therapy (CADT) prior to use in a veteran population.

OBJECTIVE:

To determine whether ranolazine, when added to optimized doses of CADT, improves angina in a veteran population with CSA and refractory symptoms.

METHODS:

In an observational retrospective study, 35 patients prescribed ranolazine and having a baseline Seattle Angina Questionnaire (SAQ) administered at a Veterans Affairs medical center in Gainesville, FL, were evaluated. Patients who were prescribed ranolazine by a provider from outside the institution and did not obtain a baseline SAQ were excluded. The primary outcome measure was the change in SAQ scores from baseline to 1 and 3 months after initiation of ranolazine treatment. Secondary measures included clinically significant QTc interval prolongation (>500 msec or an increase of at least 60 msec from baseline), adverse drug reactions, discontinuation rates, and drug-drug interactions.

RESULTS:

The addition of ranolazine to optimized CADT was associated with improvement in all dimensions of the SAQ scores at 1 and 3 months compared to baseline scores (p < 0.001 for all dimensions). Mean changes in SAQ dimension scores at 1 and 3 months, respectively, were as follows: physical limitation, +9.86 and +11.94; angina stability, +39.29 and +32.69; angina frequency, +26.79 and +25.38; treatment satisfaction, +11.38 and +10.66; and disease perception, +16.85 and +18.59. Improvments in all dimensions, except treatment satisfaction, were clinically significant as defined by set criteria. Of the 7 patients whose ranolazine dosages were increased to 1000 mg twice daily, only 2 patients were able to maintain treatment at that dosage.

CONCLUSIONS:

Ranolazine added to optimized doses of CADT demonstrated an improvement in angina symptoms when given to a veteran population with persistent CSA.

Pathophysiology of the cardiac late Na current and its potential as a drug target

A pathological increase in the late component of the cardiac Na(+) current, I(NaL), has been linked to disease manifestation in inherited and acquired cardiac diseases including the long QT variant 3 (LQT3) syndrome and heart failure. Disruption in I(NaL) leads to action potential prolongation, disruption of normal cellular repolarization, development of arrhythmia triggers, and propensity to ventricular arrhythmia. Attempts to treat arrhythmogenic sequelae from inherited and acquired syndromes pharmacologically with common Na(+) channel blockers (e.g. flecainide, lidocaine, and amiodarone) have been largely unsuccessful. This is due to drug toxicity and the failure of most current drugs to discriminate between the peak current component, chiefly responsible for single cell excitability and propagation in coupled tissue, and the late component (I(NaL)) of the Na(+) current. Although small in magnitude as compared to the peak Na(+) current (~1-3%), I(NaL) alters action potential properties and increases Na(+) loading in cardiac cells. With the increasing recognition that multiple cardiac pathological conditions share phenotypic manifestations of I(NaL) upregulation, there has been renewed interest in specific pharmacological inhibition of I(Na). The novel antianginal agent ranolazine, which shows a marked selectivity for late versus peak Na(+) current, may represent a novel drug archetype for targeted reduction of I(NaL). This article aims to review common pathophysiological mechanisms leading to enhanced I(NaL) in LQT3 and heart failure as prototypical disease conditions. Also reviewed are promising therapeutic strategies tailored to alter the molecular mechanisms underlying I(Na) mediated arrhythmia triggers.

Role of ranolazine in angina, heart failure, arrhythmias, and diabetes

Ranolazine which is currently approved as an antianginal agent reduces the Na-dependent Ca overload via inhibition of the late sodium current (late I(Na)) and thus improves diastolic tone and oxygen handling during myocardial ischemia. According to accumulating evidence ranolazine also exerts beneficial effects on diastolic and systolic heart failure where late I(Na) was also found to be elevated. Moreover, late I(Na) plays a crucial role as an arrhythmic substrate. Ranolazine has been described to have antiarrhythmic effects on ventricular as well as atrial arrhythmias without any proarrythmia or severe organ toxicity as it is common for several antiarrhythmic drugs. In patients with diabetes, treatment with ranolazine led to a significant improvement of glycemic control. In this article possible new clinical indications of the late I(Na)-inhibitor ranolazine are reviewed. We summarize novel experimental and clinical studies and discuss the significance of the available data.

Antiadrenergic and hemodynamic effects of ranolazine in conscious dogs

Effects of ranolazine alone and in the presence of phenylephrine (PE) or isoproterenol (ISO) on hemodynamics, coronary blood flow and heart rate (HR) in the absence and presence of hexamethonium (a ganglionic blocker) were studied in conscious dogs. Ranolazine (0.4, 1.2, 3.6, and 6 mg/kg, intravenous) alone caused transient (<1 minute) and reversible hemodynamic changes. PE (0.3-10 μg/kg) caused a dose-dependent increase in blood pressure and decrease in HR. ISO (0.01-0.3 μg/kg) caused a dose-dependent decrease in blood pressure and an increase in HR. Ranolazine at high (11-13 mM), but not at moderate (4-5 mM) concentrations partially attenuated changes in mean arterial blood pressure and HR caused by either PE or ISO in normal conscious dogs. However, in dogs treated with hexamethonium (20 mg/kg) to cause autonomic blockade, ranolazine (both 4-5 and 11-13 μM) significantly attenuated both the PE- and ISO-induced changes in mean arterial blood pressure. The results suggest that a potential antiadrenergic effect of ranolazine was masked by autonomic control mechanisms in conscious dogs but could be observed when these mechanisms were inhibited (eg, in the hexamethonium-treated dog). Ranolazine, at plasma concentrations <10 μM and in conscious dogs with intact autonomic regulation, had minimal antiadrenergic (α and β) effects.

Extended-release ranolazine: critical evaluation of its use in stable angina

Coronary heart disease is the major cause of morbidity and mortality throughout the world, and is responsible for approximately one of every six deaths in the US. Angina pectoris is a clinical syndrome characterized by discomfort, typically in the chest, neck, chin, or left arm, induced by physical exertion, emotional stress, or cold, and relieved by rest or nitroglycerin. The main goals of treatment of stable angina pectoris are to improve quality of life by reducing the severity and/or frequency of symptoms, to increase functional capacity, and to improve prognosis. Ranolazine is a recently developed antianginal with unique methods of action. In this paper, we review the pharmacology of ranolazine, clinical trials supporting its approval for clinical use, and studies of its quality of life benefits. We conclude that ranolazine has been shown to be a reasonable and safe option for patients who have refractory ischemic symptoms despite the use of standard medications (for example, nitrates, beta-adrenergic receptor antagonists, and calcium channel antagonists) for treatment of anginal symptoms, and also provides a modestly improved quality of life.

Stable angina pectoris: antianginal therapies and future directions

Advances in pharmacotherapy for stable angina have produced a wide choice of drugs with various mechanisms of action, potentially enabling individualized, patient-specific treatment strategies to be developed. In this Review, the various treatment options for patients with stable angina are discussed. Data from randomized, clinical trials of established and novel drugs are reviewed, with particular emphasis on the proposed mechanisms of action, benefits of therapy, and adverse-effect profiles. The role of coronary revascularization in conjunction with optimal medical therapy as a treatment strategy is discussed, although drug therapy might reduce the need for prompt revascularization if the procedure is being considered solely for the purpose of alleviating angina. Finally, trials to investigate stimulation of angiogenesis using growth-factor, gene, and cell therapy are used to illustrate the challenges of chemically inducing the growth of adequate, durable blood vessels.

[New agents for the therapy of angina pectoris]

There is a renaissance of medical treatment of chronic angina pectoris despite of advances in interventional therapy. New drugs include nicorandil, ivabradine and ranolazine. Nicorandil dilates venous and arterial vessels via relaxation of smooth muscle cells. Since the drug has only recently been approved, the German experience is limited. Ivabradine exerts an anti-anginous effect by selective action on the sinus node with reduction of heart rate. Multiple studies have demonstrated its anti-anginal efficacy, which has also been shown if it was used as an additional therapy to classic anti-anginal treatment. Its use is reasonable as a substitute for beta-blockers or as an "add-on therapy" combined with beta-blockers, if the target heart rate for treatment of angina pectoris has not been reached. Ranolazine delays the late sodium current into the myocytes. Thereby, it improves the diastolic ventricular function and the microcirculation of the myocardium. Several large studies confirmed the anti-anginal efficacy of the drug. Currently it is used if angina pectoris still occurs under a combined treatment with different classic anti-anginal drugs.

How were new medicines discovered?

Preclinical strategies that are used to identify potential drug candidates include target-based screening, phenotypic screening, modification of natural substances and biologic-based approaches. To investigate whether some strategies have been more successful than others in the discovery of new drugs, we analysed the discovery strategies and the molecular mechanism of action (MMOA) for new molecular entities and new biologics that were approved by the US Food and Drug Administration between 1999 and 2008. Out of the 259 agents that were approved, 75 were first-in-class drugs with new MMOAs, and out of these, 50 (67%) were small molecules and 25 (33%) were biologics. The results also show that the contribution of phenotypic screening to the discovery of first-in-class small-molecule drugs exceeded that of target-based approaches - with 28 and 17 of these drugs coming from the two approaches, respectively - in an era in which the major focus was on target-based approaches. We postulate that a target-centric approach for first-in-class drugs, without consideration of an optimal MMOA, may contribute to the current high attrition rates and low productivity in pharmaceutical research and development.

Class I/B antiarrhythmic property of ranolazine, a novel antianginal agent, in dog and human cardiac preparations

The aim of this study was to investigate the cellular electrophysiological effects of ranolazine on action potential characteristics. The experiments were carried out in dog and human cardiac preparations using the conventional microelectrode technique. In dog Purkinje fibres ranolazine produced a concentration- and frequency-dependent depression of the maximum rate of depolarization (V(max)) while action potential duration (APD) was shortened. In dog and human right ventricular papillary muscle ranolazine exerted no significant effect on APD, while it produced, like mexiletine, use-dependent depression of V(max) with relatively fast onset and offset kinetics. In dog midmyocardial preparations the drug did not exert statistically significant effect on repolarization at 10 μM, although a tendency toward prolongation was observed at 20 μM. A moderate lengthening of APD(90) by ranolazine was noticed in canine atrial preparations obtained from dogs in sinus rhythm and in tachypacing induced remodelled preparations. Use-dependent depression of V(max) was more pronounced in atria from dogs in sinus rhythm than those in remodelled atria or in the ventricle. These findings indicate that ranolazine, in addition to its known late sodium current blocking effect, also depresses peak I(Na) with class I/B antiarrhythmic characteristics. Although peak I(Na) inhibition by ranolazine is stronger in the atria, it is also substantial (at fast stimulation frequencies) in ventricular preparations. Ranolazine also decreased the dispersion of ventricular repolarization (the difference in APD(90) values between Purkinje fibres and papillary muscles), which can contribute to the antiarrhythmic property of the drug.

Ranolazine improves angina in women with evidence of myocardial ischemia but no obstructive coronary artery disease

OBJECTIVES

We conducted a pilot study for a large definitive clinical trial evaluating the impact of ranolazine in women with angina, evidence of myocardial ischemia, and no obstructive coronary artery disease (CAD).

BACKGROUND

Women with angina, evidence of myocardial ischemia, but no obstructive CAD frequently have microvascular coronary dysfunction. The impact of ranolazine in this patient group is unknown.

METHODS

A pilot randomized, double-blind, placebo-controlled, crossover trial was conducted in 20 women with angina, no obstructive CAD, and ≥ 10% ischemic myocardium on adenosine stress cardiac magnetic resonance (CMR) imaging. Participants were assigned to ranolazine or placebo for 4 weeks separated by a 2-week washout. The Seattle Angina Questionnaire and CMR were evaluated after each treatment. Invasive coronary flow reserve (CFR) was available in patients who underwent clinically indicated coronary reactivity testing. CMR data analysis included the percentage of ischemic myocardium and quantitative myocardial perfusion reserve index (MPRI).

RESULTS

The mean age of subjects was 57 ± 11 years. Compared with placebo, patients on ranolazine had significantly higher (better) Seattle Angina Questionnaire scores, including physical functioning (p = 0.046), angina stability (p = 0.008), and quality of life (p = 0.021). There was a trend toward a higher (better) CMR mid-ventricular MPRI (2.4 [2.0 minimum, 2.8 maximum] vs. 2.1 [1.7 minimum, 2.5 maximum], p = 0.074) on ranolazine. Among women with coronary reactivity testing (n = 13), those with CFR ≤ 3.0 had a significantly improved MPRI on ranolazine versus placebo compared to women with CFR > 3.0 (Δ in MPRI 0.48 vs. -0.82, p = 0.04).

CONCLUSIONS

In women with angina, evidence of ischemia, and no obstructive CAD, this pilot randomized, controlled trial revealed that ranolazine improves angina. Myocardial ischemia may also improve, particularly among women with low CFR. These data document approach feasibility and provide outcome variability estimates for planning a definitive large clinical trial to evaluate the role of ranolazine in women with microvascular coronary dysfunction. (Microvascular Coronary Disease In Women: Impact Of Ranolazine; NCT00570089).

The effect of ranolazine on the vasodilator-induced myocardial perfusion abnormality

BACKGROUND

We previously reported that ranolazine improved myocardial ischemia during exercise myocardial perfusion imaging (MPI). Since the mechanism of reversible perfusion defects is different in exercise than vasodilator MPI, and based on the mechanism of action of ranolazine, we hypothesized that vasodilator stress MPI may fail to show improvement in myocardial perfusion pattern.

METHODS

Patients (n = 18) with known coronary artery disease and with reversible perfusion defects on a clinically indicated vasodilator stress MPI were re-studied 4 weeks after ranolazine (500-1000 mg PO BID) was added to their conventional treatment in an open-label trial. Perfusion pattern was assessed using automated methods.

RESULTS

The baseline left ventricular ejection fraction was 59% ± 14%. The total perfusion defect (measured by polar maps) was 22% ± 13% before and 21% ± 16% of LV myocardium after treatment (P = NS). The reversible defect size was 14% ± 10% before and 14% ± 11% of LV myocardium after treatment (P = NS). The automated-derived summed stress score was 12 ± 8 before and 12 ± 10 after treatment (P = NS) and the automated-derived summed difference score was 6 ± 5 before and 6 ± 5 after treatment (P = NS). Only 3 patients showed a decrease in reversible perfusion defect size with treatment.

CONCLUSION

Vasodilator stress MPI failed to show improvement in perfusion pattern after ranolazine treatment in most patients with baseline reversible defects. This is consistent with the unique anti-ischemic mechanism of ranolazine, which acts on the late I Na channel.

Ranolazine for the treatment of heart failure with preserved ejection fraction: background, aims, and design of the RALI-DHF study

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF), formerly referred to as diastolic heart failure (DHF), accounts for >50% of all HF patients. So far, there has been no specific treatment for impaired left ventricular (LV) relaxation. Data from in vitro and animal studies indicate that ranolazine improves diastolic function by inhibiting the late sodium current.

HYPOTHESIS

RAnoLazIne for the Treatment of Diastolic Heart Failure (RALI-DHF) is a prospective, single-center, randomized, double-blind, placebo-controlled proof-of-concept study to determine if ranolazine compared with placebo will be more effective in improving diastolic function in patients with HFpEF.

METHODS

Twenty patients with HFpEF (EF ≥ 50% and ratio of transmitral Doppler early filling velocity to tissue Doppler early diastolic mitral annular velocity [E/E'] >15 or N-terminal pro-type brain natriuretic peptide >220 pg/mL) will be randomized to receive ranolazine or placebo in a 1.5:1 ratio during their catheterization if the LV end-diastolic pressure is ≥18 mm Hg and the time constant of relaxation (τ) is ≥50 ms. Treatment will consist of intravenous infusion of study drug (or placebo) for 24 hours, followed by oral treatment for a total of 14 days.

ENDPOINTS

The study will include the following exploratory endpoints: (1) change from baseline to 30 minutes from initiation of intravenous study drug administration during cardiac catheterization hemodynamic parameters at both resting and paced (120 beats per minute) conditions: τ, LV end-diastolic pressure, and dP/dt(min) .; and (2) change from baseline to day 14 in E/E', maximal oxygen consumption, and N-terminal pro-type brain natriuretic peptide.

CONCLUSIONS

The RALI-DHF study is designed as a translational study to bridge the gap between basic science and therapeutics and to determine if ranolazine, compared with placebo, will be more effective in improving diastolic function in patients with HFpEF.