Inter-ethnic comparisons of the pharmacokinetics of the HMG-CoA reductase inhibitor cerivastatin

Protocol for systematic review and meta-analysis: impact of statins as immune-modulatory agents on inflammatory markers in adults with chronic diseases

INTRODUCTION

Statins, also known as 3-hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductase inhibitors, are lipid-lowering agents that are central in preventing or reducing the complications of atherosclerotic cardiovascular disease. Because statins have anti-inflammatory properties, there is considerable interest in their therapeutic potential in other chronic inflammatory conditions. We aim to identify the statin with the greatest ability to reduce systemic inflammation, independent of the underlying disease entity.

METHODS AND ANALYSIS

We aim to conduct a comprehensive search of published and peer-reviewed randomised controlled clinical trials, with at least one intervention arm of a Food & Drug Administration-licensed or European Medicines Agency-licensed statin and a minimum treatment duration of 12 weeks. Our objective is to investigate the effect of statins (atorvastatin, fluvastatin, pitavastatin, pravastatin, rosuvastatin, simvastatin) on lipid profile, particularly, cholesterol low-density lipoprotein and inflammation markers such as high-sensitive C reactive protein (hsCRP), CRP, tumour necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), IL-6, IL-8, soluble cluster of differentiation 14 (sCD14) or sCD16 in adults, published in the last 20 years (between January 1999 and December 2019). We aim to identify the most potent statin to reduce systemic inflammation and optimal dosing. The following databases will be searched: Medline, Scopus, Web of Science and Cochrane Library of Systematic Reviews. The risk of bias of included studies will be assessed by Cochrane Risk of Bias Tool and Quality Assessment Tool for Quantitative Studies. The quality of studies will be assessed, to show uncertainty, by the Jadad Score. If sufficient evidence is identified, a meta-analysis will be conducted with risk ratios or ORs with 95% CIs in addition to mean differences.

ETHICS AND DISSEMINATION

Ethics approval is not required as no primary data will be collected. Results will be presented at conferences and published in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42020169919.

Tissue-Engineered Human Myobundle System as a Platform for Evaluation of Skeletal Muscle Injury Biomarkers

Traditional serum biomarkers used to assess skeletal muscle damage, such as activity of creatine kinase (CK), lack tissue specificity and sensitivity, hindering early detection of drug-induced myopathies. Recently, a novel four-factor skeletal muscle injury panel (MIP) of biomarkers consisting of skeletal troponin I (sTnI), CK mass (CKm), fatty-acid-binding protein 3 (Fabp3), and myosin light chain 3, has been shown to have increased tissue specificity and sensitivity in rodent models of skeletal muscle injury. Here, we evaluated if a previously established model of tissue-engineered functional human skeletal muscle (myobundle) can allow detection of the MIP biomarkers after injury or drug-induced myotoxicity in vitro. We found that concentrations of three MIP biomarkers (sTnI, CKm, and Fabp3) in myobundle culture media significantly increased in response to injury by a known snake venom (notexin). Cerivastatin, a known myotoxic statin, but not pravastatin, induced significant loss of myobundle contractile function, myotube atrophy, and increased release of both traditional and novel biomarkers. In contrast, dexamethasone induced significant loss of myobundle contractile function and myotube atrophy, but decreased the release of both traditional and novel biomarkers. Dexamethasone also increased levels of matrix metalloproteinase-2 and -3 in the culture media which correlated with increased remodeling of myobundle extracellular matrix. In conclusion, this proof-of-concept study demonstrates that tissue-engineered human myobundles can provide an in vitro platform to probe patient-specific drug-induced myotoxicity and performance assessment of novel injury biomarkers to guide preclinical and clinical drug development studies.

In-vitro inhibitory effect of Tualang honey on cytochrome P450 2C8 activity

Objectives

To investigate the effect of Tualang honey on cytochrome P450 2C8 (CYP2C8) activity in vitro using an amodiaquine N-desethylase assay.

Methods

CYP2C8 and NADPH cytochrome P450 reductase was cotransformed, expressed and harvested. The incubation assay contained expressed proteins, MgCl2, NADP, glucose 6-phosphate, glucose-6-phosphate dehydrogenase, potassium phosphate buffer, and amodiaquine. The rate of conversion of amodiaquine to desethylamodiaquine, the metabolite, was determined using a high performance liquid chromatography (HPLC) method. The inhibition parameters, IC50 (concentration of inhibitor causing 50% inhibition of original enzyme activity) and apparent inhibition constant (Ki) values were determined.

Key findings

The recombinant proteins were successfully expressed and used to investigate the effect of Tualang honey on CYP2C8 activity. The activity was measured by the rate of metabolism of amodiaquine to desethylamodiaquine determined using a successfully developed HPLC method. Kinetic parameters as determined by nonlinear least-squares regression and evaluated with Aikeike's goodness of fit criteria revealed that Tualang honey competitively inhibited CYP2C8 activity in a dose-dependent manner. Maximum inhibition of 80% occurred at 0.01% honey. The IC50 and Ki values were (10.0 ± 3.0) × 10−3% and (5.1 ± 0.5) × 10−3% w/v, respectively.

Conclusions

This study has provided evidence for the in vitro inhibition of CYP2C8-mediated amodiaquine N-desethylase activity by Tualang honey. It revealed that honey, through this inhibition, may have the potential to cause in-vivo drug–food interaction with drugs metabolized by CYP2C8.

Statin dose in Asians: is pharmacogenetics relevant?

Historically the efficacy and safety of statins has mostly been studied in western populations. Few such studies have been carried out in Asians until recent years. These studies revealed interesting similarities and differences for statin use between Asians and Caucasians. One clinically important question subsequently raised is whether Asians need lower statin doses compared with Caucasians. Many practicing physicians believe that statin doses are lower in Asians because of the generally lower bodyweight and BMI. Whether this belief is based on sound scientific evidence needs to be reviewed. Furthermore, since the decision of optimal dose is based on both efficacy and safety, both of which may be impacted by genetic factors, one may ask whether pharmacogenetics plays a role in the dose difference, if such a difference exists. There is a clinical need to critically and comprehensively article the literature to answer these questions, and summarize future directions of research in the field. This article serves the above purpose.

Pharmacological actions of statins: a critical appraisal in the management of cancer

Statins, among the most commonly prescribed drugs worldwide, are cholesterol-lowering agents used to manage and prevent cardiovascular and coronary heart diseases. Recently, a multifaceted action in different physiological and pathological conditions has been also proposed for statins, beyond anti-inflammation and neuroprotection. Statins have been shown to act through cholesterol-dependent and -independent mechanisms and are able to affect several tissue functions and modulate specific signal transduction pathways that could account for statin pleiotropic effects. Typically, statins are prescribed in middle-aged or elderly patients in a therapeutic regimen covering a long life span during which metabolic processes, aging, and concomitant novel diseases, including cancer, could occur. In this context, safety, toxicity, interaction with other drugs, and the state of health have to be taken into account in subjects treated with statins. Some evidence has shown a dichotomous effect of statins with either cancer-inhibiting or -promoting effects. To date, clinical trials failed to demonstrate a reduced cancer occurrence in statin users and no sufficient data are available to define the long-term effects of statin use over a period of 10 years. Moreover, results from clinical trials performed to evaluate the therapeutic efficacy of statins in cancer did not suggest statin use as chemotherapeutic or adjuvant agents. Here, we reviewed the pharmacology of the statins, providing a comprehensive update of the current knowledge of their effects on tissues, biological processes, and pathological conditions, and we dissected the disappointing evidence on the possible future use of statin-based drugs in cancer therapy.

Coronary heart disease in moderately hypercholesterolemic, hypertensive black and non-black patients randomized to pravastatin versus usual care: the antihypertensive and lipid lowering to prevent heart attack trial (ALLHAT-LLT)

BACKGROUND

In previous analyses in ALLHAT, blacks had a significantly lower risk of coronary heart disease (CHD) in the pravastatin group compared to the usual care group, whereas non-blacks had no benefit from pravastatin. No previous statin trial has reported results separately in blacks.

OBJECTIVES

The study aimed to determine if apparent racial differences in CHD in ALLHAT are explained by differences in baseline characteristics, adherence during the trial, or achieved blood pressure and lipid lowering.

METHODS

This was a prespecified subgroup analysis of a randomized controlled trial. Hypertensive, moderately hypercholesterolemic participants were assigned to open-label pravastatin (40 mg/d) or usual care. The outcome was a composite of nonfatal myocardial infarction and fatal CHD. We performed intention-to-treat survival analyses using Cox proportional hazards models, adjusting for baseline covariates (age, sex, aspirin use, history of CHD and diabetes, and baseline hypertension treatment) and time-varying levels of blood pressure and total cholesterol.

RESULTS

After adjustment for baseline characteristics, there remained a significant interaction between race and treatment group (P = .02). In stratified models, blacks in the pravastatin group had a 29% lower risk of CHD (hazard ratio [HR] 0.71, 95% CI 0.57-0.90, P = .005) compared to those in the usual care group, whereas non-blacks had no benefit (HR 1.00, 95% CI 0.85-1.19, P = .95). With further adjustment for achieved blood pressure and total cholesterol, the HR in blacks was 0.65 (95% CI 0.45-0.96, P = .03) and in non-blacks was 1.07 (95% CI 0.81-1.41, P = .65).

CONCLUSIONS

Our results suggest that pravastatin is effective in preventing CHD in blacks.

Adding a medicine to the WHO model list of essential medicines

Although the concept of essential medicines is not new, the processes that lead to placement of these medicines on the World Health Organization Model List of Essential Medicines are not well understood. Here, we describe the process by which we added a class of drugs, statins, to the Model List to help combat the growing global epidemic of cardiovascular disease.

Prediction ofin vivodrug clearance fromin vitrodata. II: Potential inter-ethnic differences

Potential differences in drug clearance between Japanese and Caucasians were investigated by integrating data on demography, liver size, the abundance of the major cytochromes P450 and in vitro metabolic parameters. Eleven drugs (alprazolam, caffeine, chlorzoxazone, cyclosporine, midazolam, omeprazole, sildenafil, tolbutamide, triazolam, S-warfarin and zolpidem) fulfilled the entry criteria of the study (i.e. the necessary in vitro metabolism data were available and clearance values had been reported both in Caucasians and Japanese). Values of relevant biological variables were obtained from the literature, and clearance predictions were made using the Simcyp Population-Based ADME Simulator. The ratios of observed oral clearance (CLp.o.) values in Caucasians compared with Japanese ranged from 0.6 to 2.8 (integrating data from 82 sources). The CLp.o. values for alprazolam, caffeine and zolpidem were not statistically different between Caucasian and Japanese (p>0.05), whereas those for chorzoxazone, cyclosporine, omeprazole, tolbutamide and triazolam were higher in Caucasians (p<0.05), and those for midazolam, sildenafil and S-warfarin were higher in Japanese (p<0.05). CLp.o. values, predicted from in vitro data, were within 3-fold of observed in vivo values for seven of the 11 drugs in Japanese. Values for the predicted ratios ranged from 1.6 to 4.9. The predicted ratios were not significantly different from observed ratios for cyclosporine, omeprazole, tolbutamide and triazolam. Only partial success in predicting ethnic differences in clearance indicates the need for larger and more reliable databases on relevant variables. With such information, in silico predictions might be used with more confidence to decrease the need for repeating pharmacokinetic studies in different ethnic groups.

Evidence-based prescribing of statins: a developing world perspective

Although statins reduce the incidence of cardiovascular disease, they are expensive. How should trial evidence on statins be applied to a resource-poor setting?

Ethnic or Racial Differences Revisited

Ethnic or racial differences in pharmacokinetics and pharmacodynamics have been attributed to the distinctions in the genetic, physiological and pathological factors between ethnic/racial groups. These pharmacokinetic/pharmacodynamic differences are also known to be influenced by several extrinsic factors such as socioeconomic background, culture, diet and environment. However, it is noted that other factors related to dosage regimen and dosage form have largely been ignored or overlooked when conducting or analysing pharmacokinetic/pharmacodynamic studies in relation to ethnicity/race. Potential interactions can arise between the characteristics of ethnicity/race and a unique feature of dosage regimen or dosage form used in the study, which may partly account for the observed pharmacokinetic/pharmacodynamic differences between ethnic/racial groups. Ethnic/racial differences in pharmacokinetics/pharmacodynamics can occur from drug administration through a specific route that imparts distinct pattern of absorption, distribution, transport, metabolism or excretion. For example, racial differences in the first-pass metabolism of a drug following oral administration may not be relevant when the drug is applied to the skin. On the other hand, ethnic/racial difference in pharmacokinetics/pharmacodynamics can also happen via two different routes of drug delivery, with varying levels of dissimilarity between routes. For example, greater ethnic/racial differences were observed in oral clearance than in systemic clearance of some drugs, which might be explained by the pre-systemic factors involved in the oral administration as opposed to the intravenous administration. Similarly, changes in the dose frequency and/or duration may have profound impact on the ethnic/racial differences in pharmacokinetic/pharmacodynamic outcome. Saturation of enzymes, transporters or receptors at high drug concentrations is a possible reason for many observed ethnic/racial discrepancies between single- and multiple-dose regimens, or between low- and high-dose administrations. The presence of genetic polymorphism of enzymes and/or transporters can further complicate the analysis of pharmacokinetic/pharmacodynamic data in ethnic/racial populations. Even within the same dosage regimen, the use of different dosage forms may trigger significantly different pharmacokinetic/pharmacodynamic responses in various ethnic/racial groups, given that different dosage forms may exhibit different rates of drug release, may release the drug at different sites, and/or have different retention times at specific sites of the body. It is thus cautioned that the pharmacokinetic/pharmacodynamic data obtained from different ethnic/racial groups cannot be indiscriminately compared or combined for analysis if there is a lack of homogeneity in the apparent 'extrinsic' factors, including dosage regimen and dosage form.

Differences in drug pharmacokinetics between East Asians and Caucasians and the role of genetic polymorphisms

Interethnic variability in pharmacokinetics can cause unexpected outcomes such as therapeutic failure, adverse effects, and toxicity in subjects of different ethnic origin undergoing medical treatment. It is important to realize that both genetic and environmental factors can lead to these differences among ethnic groups. The International Conference on Harmonization (ICH) published a guidance to facilitate the registration of drugs among ICH regions (European Union, Japan, the United States) by recommending a framework for evaluating the impact of ethnic factors on a drug's effect, as well as its efficacy and safety at a particular dosage and dosage regimen. This review focuses on the pharmacokinetic differences between East Asians and Caucasians. Differences in metabolism between East Asians and Caucasians are common, especially in the activity of several phase I enzymes such as CYP2D6 and the CYP2C subfamily. Before drug therapy, identification of either the genotype and/or the phenotype for these enzymes may be of therapeutic value, particularly for drugs with a narrow therapeutic index. Furthermore, these differences are relevant for international drug approval when regulatory agencies must decide if they accept results from clinical trials performed in other parts of the world.

Efficacy and safety of simvastatin in Asian and non-Asian coronary heart disease patients: a comparison of the GOALLS and STATT studies

BACKGROUND

Asians are thought to be more responsive to the lipid-lowering effects of statins than non-Asians although there are no head-to-head trials that examine this perception.

OBJECTIVE

To compare the results of the GOALLS and STATT studies that used similar titrate-to-goal protocols with 20 mg up to 80 mg simvastatin in Asian and non-Asian coronary heart disease (CHD) patients.

METHODS

GOALLS (N = 198; included non-Asians and Asians) and STATT (N = 133; included Asians only) were both multi-center, open-label 14-week studies in CHD patients with serum low density lipoprotein cholesterol (LDL-C) levels 115 mg/dL-180 mg/dL and triglycerides (TG) levels < or = 400 mg/dL. Simvastatin was titrated from 20 mg/day up to 80 mg/day in order to achieve the National Cholesterol Education Program (NCEP) LDL-C target < or = 100 mg/dL. The primary efficacy variable was the percentage of patients attaining the NCEP LDL-C target at Week 14. Secondary endpoints included proportion of patients achieving the European Society of Cardiology/European Atherosclerosis Society/European Society of Hypertension (European) LDL-C target < or = 115 mg/dL at Week 14 and percentage change in lipid parameters. Safety and tolerability were assessed by monitoring adverse experiences and safety laboratory tests. Fifteen Asian patients were part of the GOALLS cohort and their data were compared separately with results of non-Asians from GOALLS and Asians from the STATT study.

RESULTS

After 14 weeks of simvastatin treatment, 87.1% of GOALLS non-Asians, 85.7% of GOALLS Asians, and 78.2% of STATT patients attained the NCEP LDL-C target. At Week 14, 94.4%, 92.9%, and 91.7% of the GOALLS non-Asians, GOALLS Asians, and STATT patients achieved the European LDL-C target, respectively. The average treatment doses to attain NCEP and European targets were comparable among groups. The percentage reductions in lipid parameters from baseline to week 14 were similar among groups except, changes in high density lipoprotein cholesterol and apolipoprotein A-I favored Asian subjects. There was also a greater reduction in TG in the STATT study, but this was not consistent with TG reductions experienced by Asians in the GOALLS study. In both studies, simvastatin was generally well tolerated by all patients across the dosage range of 20 mg-80 mg. No cases of rhabdomyolysis or myopathy were reported in either study.

CONCLUSIONS

A great majority of CHD patients is able to achieve LDL-C treatment goals (up to 90%) on simvastatin regardless of racial background. Simvastatin treatment at doses of 20 mg-80 mg is well-tolerated in Asian and non-Asian CHD patients. This side-by-side comparison provides evidence that Asian and non-Asian CHD populations respond similarly to comparable doses of simvastatin.

A review and assessment of potential sources of ethnic differences in drug responsiveness

The International Conference on Harmonization (ICH) E5 guidelines were developed to provide a general framework for evaluating the potential impact of ethnic factors on the acceptability of foreign clinical data, with the underlying objective to facilitate global drug development and registration. It is well recognized that all drugs exhibit significant inter-subject variability in pharmacokinetics and pharmacologic response and that such differences vary considerably among individual drugs and depend on a variety of factors. One such potential factor involves ethnicity. The objective of the present work was to perform an extensive review of the world literature on ethnic differences in drug disposition and responsiveness to determine their general significance in relation to drug development and registration. A few examples of suspected ethnic differences in pharmacokinetics or pharmacodynamics were identified. The available literature, however, was found to be heterologous, including a variety of study designs and research methodologies, and most of the publications were on drugs that were approved a long time ago.

Gender, ethnicity, and genes in cardiovascular disease. Part 2: implications for pharmacotherapy

Women are underrepresented in clinical trials. Lower doses of beta-blockers are required for Southeast Asians. ACE and ARB's are teratogenic in the second trimester. Torsades de Pointes is more common in women related to a longer QT-interval. Lower dose OCPs decrease the risk of MI, stroke and thrombosis. HRTs are not effective for CAD prevention.

Antiinflammatory and antiarteriosclerotic actions of HMG-CoA reductase inhibitors in a rat model of chronic inhibition of nitric oxide synthesis

Recent studies suggest that some of the beneficial effects of 3-hydroxyl-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) may be due to their cholesterol-lowering independent effects on the blood vessels. Chronic inhibition of endothelial nitric oxide (NO) synthesis by oral administration of N(omega)-nitro-L-arginine methyl ester (L-NAME) to rats induces early vascular inflammation as well as subsequent arteriosclerosis. The aim of the study is to test whether treatment with statins attenuates such arteriosclerotic changes through their cholesterol-lowering independent effects. We investigated the effect of statins (pravastatin and cerivastatin) on the arteriosclerotic changes in the rat model. We found that treatment with statins did not affect serum lipid levels but markedly inhibited the L-NAME-induced vascular inflammation and arteriosclerosis. Treatment with statins augmented endothelial NO synthase activity in L-NAME-treated rats. We also found the L-NAME induced increase in Rho membrane translocation in hearts and its prevention by statins. Such vasculoprotective effects of statins were suppressed by the higher dose of L-NAME. In summary, in this study, we found that statins such as pravastatin and cerivastatin inhibited vascular inflammation and arteriosclerosis through their lipid-lowering independent actions in this model. Such antiarteriosclerotic effects may involve the increase in endothelial NO synthase activity and the inhibition of Rho activity.

Molecular basis of ethnic differences in drug disposition and response

Ethnicity is an important demographic variable contributing to interindividual variability in drug metabolism and response. In this rapidly expanding research area many genetic factors that account for the effects of ethnicity on pharmacokinetics, pharmacodynamics, and drug safety have been identified. This review focuses on recent developments that have improved understanding of the molecular mechanisms responsible for such interethnic differences. Genetic variations that may provide a molecular basis for ethnic differences in drug metabolizing enzymes (CYP 2C9, 2C19, 2D6, and 3A4), drug transporter (P-glycoprotein), drug receptors (adrenoceptors), and other functionally important proteins (eNOS and G proteins) are discussed. A better understanding of the molecular basis underlying ethnic differences in drug metabolism, transport, and response will contribute to improved individualization of drug therapy.

Clinical pharmacokinetics of cerivastatin

Cerivastatin sodium, a novel statin, is a synthetic, enantiomerically pure, pyridine derivative that effectively reduces serum cholesterol levels at microgram doses. Cerivastatin is readily and completely absorbed from the gastrointestinal tract, with plasma concentrations reaching a peak 2 to 3 hours postadministration followed by a monoexponential decay with an elimination half-life (t1/2beta) of 2 to 3 hours. Cerivastatin pharmacokinetics are linear: maximum plasma concentration (Cmax) and area under the concentration-time curve (AUC) are proportional to the dose over the range of 0.05 to 0.8 mg. No accumulation is observed on repeated administration. Cerivastatin interindividual variability is described by coefficients of variation of approximately 30 to 40% for its primary pharmacokinetic parameters AUC, Cmax and t1/2beta. The mean absolute oral bioavailability of cerivastatin is 60% because of presystemic first-pass effects. Its pharmacokinetics are not influenced by concomitant administration of food nor by the time of day at which the dose is given. Age, gender, ethnicity and concurrent disease also have no clinically significant effects. Cerivastatin is highly bound to plasma proteins (>99%). The volume of distribution at steady state of about 0.3 L/kg indicates that the drug penetrates only moderately into tissue; conversely, preclinical studies have shown a high affinity for liver tissue, the target site of action. Cerivastatin is exclusively cleared via metabolism. No unchanged drug is excreted. Cerivastatin is subject to 2 main oxidative biotransformation reactions: demethylation of the benzylic methyl ether moiety leading to the metabolite M-1 [catalysed by cytochrome P450 (CYP) 2C8 and CYP3A4] and stereoselective hydroxylation of one methyl group of the 6-isopropyl substituent leading to the metabolite M-23 (catalysed by CYP2C8). The product of the combined biotransformation reactions is a secondary minor metabolite, M-24, not detectable in plasma. All 3 metabolites are active inhibitors of hydroxymethylglutaryl-coenzyme A reductase with a similar potency to the parent drug. Approximately 70% of the administered dose is excreted as metabolites in the faeces, and 30% in the urine. Metabolism by 2 distinct CYP isoforms renders cerivastatin relatively resistant to interactions arising from inhibition of CYP. If one of the pathways is blocked, cerivastatin can be effectively metabolised by the alternative route. In addition, on the basis of in vitro investigations, there is no evidence for either cerivastatin or its metabolites having any inducing or inhibitory activity on CYP. The apparent lack of any clinically relevant interactions with a variety of drugs commonly used by patients in the target population supports this favourable drug-drug interaction profile.

[Responsibilities of clinical pharmacology in the early phase of drug development]

The path of a new drug from the idea to the product may be divided into 2 phases, namely drug discovery and drug development. Due to the scientific progress new and simple methods could be developed to determine the biological efficacy of a large number of compounds. During the first part of drug development necessary requirements for the first use in man are met by performing preclinical pharmacological, toxicological and pharmacokinetic investigations in the animal and in in-vitro testing. After a first clinical-pharmacological profile of the new substance has been established during phase I on the basis of which a decision for the continuation of the clinical trial is made, the aim of phases II and III is now to answer the important questions of the therapeutic efficacy and tolerability in a large number of patients with the target indication. Due to the continuously increasing time and costs of drug development, drug development should be streamlined combining preclinical and early clinical phases as an exploratory stage and later clinical development as a confirmatory stage. The development and appropriate use of surrogates and models may be helpful to determine drug actions in human and to assist in dose selection as the main requirement for a successful large clinical trial in the confirmatory stage. Identifying the genes responsible for the huge variations in how different patients respond to a drug, in terms of both the product's effectiveness and its side effects, and genotyping patients before including in large clinical trials may prevent selecting the wrong patient population and avoid expensive repetition of these studies. Taking responsibility as the link between research and development gives clinical pharmacology a major opportunity to assume a pivotal role in drug development. To reach this goal, clinical pharmacology must be fully integrated in the whole process of drug development from the candidate selection until the approval.

Biopharmaceutical profile of cerivastatin: a novel HMG-CoA reductase inhibitor

The biopharmaceutical properties of cerivastatin were evaluated in a series of worldwide clinico-pharmacological studies. Young healthy males aged 18-45 years were randomized to receive 0.05-0.8 mg cerivastatin orally, given either as single or multiple once-daily doses under fed or fasting conditions in the morning, with evening meal or at bedtime. Following administration, cerivastatin was rapidly and almost completely absorbed into the gastrointestinal tract (> 98%), with maximum plasma concentrations (Cmax) reached at 2-3 h post dose. The plasma concentration/time profile of the tablet is similar to an aqueous oral solution (relative bioavailability is 100%). The dose-proportionality of cerivastatin (0.05-0.8 mg) in area under the curve and Cmax showed low intra- and interindividual variability. The effect of food (single-dose studies testing administration of cerivastatin with a high-fat meal and clinical investigations in patients) or time of administration (single- and multiple-dose once-daily/twice-daily studies) had no clinically relevant effects on the pharmacokinetics of cerivastatin. Marketed tablet strengths and drug formulations from different sources were found to be bioequivalent. Cerivastatin is a noncomplicated drug with respect to its biopharmaceutical profile and bioavailability.

Rational assessment of the interaction profile of cerivastatin supports its low propensity for drug interactions

Pharmacokinetic drug-drug interactions influence drug efficacy, tolerability, and compliance. Such interactions are both more common and of more clinical relevance than often appreciated. The US Food and Drug Administration and the European Agency for the Evaluation of Medicinal Products have recently issued guidelines setting out in vitro and in vivo investigations to be conducted during drug development. These guidelines reflect the increasing interest of public health authorities in this topic. Cerivastatin is a novel, potent HMG-CoA reductase inhibitor that effectively reduces serum cholesterol levels at low daily doses. It is completely absorbed after oral administration, undergoes moderate first-pass metabolism and high plasma protein binding, and is cleared exclusively via hepatic cytochrome P450 (CYP). Unlike other drugs of its class, cerivastatin has a dual metabolic pathway, with the involvement of more than one CYP isozyme. Metabolites are cleared via both biliary and renal excretion. On the basis of this pharmacokinetic profile and a knowledge of the target population, the formal in vivo interaction programme for cerivastatin investigated many important potential cerivastatin drug-drug interactions. Cerivastatin appears to lack clinically relevant interactions with digoxin, warfarin, antacid, cimetidine, nifedipine, omeprazole, erythromycin and itraconazole.

Preclinical review of cerivastatin sodium--a step forward in HMG-CoA reductase inhibition

Epidemiological studies have established that elevated concentrations of plasma cholesterol, particularly the low density lipoprotein (LDL) cholesterol, is one of the major risk factors for the development of arteriosclerosis and ischemic heart disease. Treatment with HMG-CoA reductase inhibitors (vastatins) has become the most successful drug treatment in lowering total plasma and LDL cholesterol concentrations in the last years. The vastatins already available for treatment are therapeutically used in a dose-range between 10 and 80 mg/day. The new enantiomerically pure pyridine derivative cerivastatin sodium has demonstrated its efficacy in significantly lower doses in the microgram-range, not only in preclinical but also in clinical studies with daily doses of only 0.1-0.3 mg. The differences in the therapeutic doses are reflected by the Ki- and IC50-values from enzyme inhibition tests in comparison with various HMG-CoA reductase inhibitors. Cerivastatin sodium exhibits much higher enzyme affinity with factors between 70 and almost 200. The Ki-value for cerivastatin sodium was 1.3 x 10(-9) M in comparison to 150 x 10(-9) M for lovastatin. The extremely high enzyme affinity of cerivastatin sodium was also reflected in its high activity in vivo. In acute in vivo studies cerivastatin sodium inhibited the hepatic [14C]cholesterol synthesis from [14C]acetate in both rats and dogs by 50% after oral administration at doses of 0.002 mg/kg body weight (ED50-values). This dose was comparable to 0.3 mg/kg of lovastatin. In subchronic dog studies a dose of 0.03 mg/kg lowered the serum LDL cholesterol concentration by 35% which is comparable with doses of 8-10 mg lovastatin/kg. Interesting results were observed in cholestyramine-primed dogs when 0.1 mg cerivastatin sodium/kg p.o. markedly decreased the serum triglycerides up to 70%. Cerivastatin shows a favourable pharmacokinetic profile with high liver selectivity. Rat studies have shown almost complete absorption and rapid hepatic clearance. Cerivastatin was highly bound to plasma proteins of rats, dogs and humans (>98%). Cerivastatin metabolites were excreted mainly via feces. The metabolism of cerivastatin sodium in man follows two metabolic pathways, demethylation to metabolite M1 and stereospecific hydroxylation to M23. The three major metabolites M1, M23 and the hydroxylated and demethylated metabolite M24 are highly active inhibitors not only in vitro but also in vivo. The human specific metabolites M23 and M24 inhibited the HMG-CoA reductase isolated from rat liver with the same potency as the parent compound cerivastatin sodium (IC50: 1.0-1.2 x 10(-9) M). M1 was slightly less active. Corresponding pharmacological activity was observed in vivo. M23 and M24 inhibited [14C]cholesterol synthesis from [14C]acetate in rat liver with ED50)-values between 0.001 and 0.002 mg/kg body weight which is similar to cerivastatin sodium and M1 exhibited an ED50-value of <0.006 mg/kg The strong inhibitory activity of these metabolites, in addition to cerivastatin's high enzyme affinity may explain the extraordinary pharmacological activity of cerivastatin and its ultra-low dose in man and demonstrates cerivastatin to be the most active HMG-CoA reductase inhibitor amongst all vastatins.