Comparison of the pharmacokinetics of pitavastatin by formulation and ethnic group: an open-label, single-dose, two-way crossover pharmacokinetic study in healthy Caucasian and Japanese men

Successful Prediction of Human Hepatic Concentrations of Transported Drugs Using the Proteomics-Informed Relative Expression Factor Approach

Tissue drug concentrations determine the efficacy and toxicity of drugs. When a drug is the substrate of transporters that are present at the blood:tissue barrier, the steady-state unbound tissue drug concentrations cannot be predicted from their corresponding plasma concentrations. To accurately predict transporter-modulated tissue drug concentrations, all clearances (CLs) mediating the drug's entry and exit (including metabolism) from the tissue must be accurately predicted. Because primary cells of most tissues are not available, we have proposed an alternative approach to predict such CLs, that is the use of transporter-expressing cells/vesicles (TECs/TEVs) and relative expression factor (REF). The REF represents the abundance of the relevant transporters in the tissue vs. in the TECs/TEVs. Here, we determined the transporter-based intrinsic CL of glyburide (GLB) and pitavastatin (PTV) in OATP1B1, OATP1B3, OATP2B1, and NTCP-expressing cells and MRP3-, BCRP-, P-gp-, and MRP2-expressing vesicles and scaled these CLs to in vivo using REF. These predictions fell within a priori set twofold range of the hepatobiliary CLs of GLB and PTV, estimated from their hepatic positron emission tomography imaging data: 272.3 and 607.8 mL/min for in vivo hepatic sinusoidal uptake CL, 47.8 and 17.4 mL/min for sinusoidal efflux CL, and 0 and 4.20 mL/min for biliary efflux CL, respectively. Moreover, their predicted hepatic concentrations (area under the hepatic concentration-time curve (AUC) and maximum plasma concentration (Cmax )), fell within twofold of their mean observed data. These data, together with our previous findings, confirm that the REF approach can successfully predict transporter-based drug CLs and tissue concentrations to enhance success in drug development.

Real-World Analyses of the Safety Outcome among a General Population Treated with Statins: An Asian Population-Based Study

AIM

The safety concern of statins is still a major issue for Asians. The aim of this study is to compare the risk of statin-associated adverse events among potent statins.

METHODS

We included patients from the Taiwan National Health Insurance Research Database who had been treated with atorvastatin, rosuvastatin, or pitavastatin and were without diabetes at baseline. They were classified into three groups: usual-dose statin (atorvastatin 10 mg/d or rosuvastatin 5-10 mg/d), high-dose statin (atorvastatin 20-40 mg/d and rosuvastatin 20 mg/d), and pitavastatin (2-4 mg/d). The primary endpoint is a composite of safety events, including hepatitis, myopathy, and new-onset diabetes mellitus (NODM). We matched age, sex, and year of recruitment among the three groups (n=50,935 in each group) and then used the multivariate Cox proportional hazards model to evaluate the relation between the safety endpoint and different statin groups.

RESULTS

After a mean follow-up of 3.08±0.83 years, the safety events occurred in 9.84% in the pitavastatin group, 10.88% in the usual-dose statin group, and 10.49% in high-dose statin group. The multivariate Cox proportional hazards model indicated that usual-dose statin and high-dose statin were associated with a higher risk of the composite safety events compared with pitavastatin (adjusted hazard ratio [aHR]: 1.12, 95% confidence interval [CI]: 1.08-1.17 for usual-dose statin and aHR: 1.06, 95% CI: 1.02-1.10 for high-dose statin). The risks of hepatitis requiring hospitalization and NODM were especially lower in pitavastatin group.

CONCLUSIONS

Compared with atorvastatin and rosuvastatin, pitavastatin might be associated with a lower risk of safety events in Asians.

Obesity Pillars Roundtable: Obesity and East Asians

Background

Individuals from East Asia make up about 1/5th of the world's population. Individuals from South Asia with obesity are well-described to have increased susceptibility to cardiovascular disease (CVD) risk factors and increased risk of CVD events. Less well described are the adiposopathic effects of the disease of obesity among East Asians.

Methods

This roundtable discussion includes 3 obesity medicine specialists with experience in the clinical management of obesity among patients of East Asian descent. Included are citations regarding obesity and East Asians.

Results

In general, East Asians are at decreased risk for CVD compared to Whites and South Asians. However, compared to Whites, for the same body mass index, East Asians are at increased risk for metabolic diseases such as type 2 diabetes mellitus. Both obesity and type 2 diabetes mellitus are epidemics in East Asian countries. In this Roundtable, the panelists discuss East Asian nutrition and physical activity, with special attention given to Asian foods, especially rice. The panelists also discuss East Asian genetic predispositions for development of visceral adiposity, type 2 diabetes mellitus, as well as genetic predisposition to drug metabolism and potential drug and herbal interactions, as commonly encountered in patients with obesity. Finally, the panelists give summary tips for managing East Asian patients with obesity.

Conclusion

The three panelists of this roundtable describe their practical diagnostic processes and treatment plans for patients from East Asia, with an emphasis on a patient-centered approach to obesity in this unique population.

Efficacy and safety of statins in ethnic differences: a lesson for application in Indigenous Australian patient care

Although statins are effective in treating high cholesterol, adverse effects do occur with their use. Efficacy and tolerability vary among statins in different ethnic groups. Indigenous Australians have a high risk for cardiovascular and kidney diseases. Prescribing statins to Indigenous Australians with multi-morbidity requires different strategies to increase efficacy and reduce their toxicity. Previous studies have reported that Indigenous Australians are more susceptible to severe statin-induced myopathies. However, there is a lack of evidence in the underlying genetic factors in this population. This review aims to identify: inter-ethnic differences in the efficacy and safety of statins; major contributing factors accounting for any identified differences; and provide an overview of statin-induced adverse effects in Indigenous Australians.

Converging Generic Drug Product Development: Bioequivalence Design and Reference Product Selection

Different regulatory agencies provide criteria for selecting a reference product for bioequivalence (BE) studies. In most cases, the criteria vary from one regulatory agency to another, and, consequently, the generic companies often have to repeat the BE studies comparing the same test product with the reference product purchased from a particular country. In addition to being a cost-intensive exercise, this practice is also unethical. The purpose of this article is to discuss the current policy of major regulatory authorities on the selection of the reference product for pharmaceutical equivalence (PE) and BE studies, the cost implications of such regulatory practices, and to also explore the opportunity to harmonize the reference product selection criteria for reducing repetitive BE studies. The regulatory guidance documents of major jurisdictions are reviewed for similarities and differences in generic product definition, BE study design and conduct, and reference product selection criteria for PE and BE studies. A case study is presented to understand how harmonisation can be achieved and how the economic benefits of this harmonisation cannot be underestimated. Harmonisation in reference product selection criteria can pave the way for a common BE study(s) that would be acceptable to the majority of regulatory agencies, and would not only significantly reduce operating costs but would also minimize the exposure of healthy human beings to drugs.

Statin Safety and Associated Adverse Events: A Scientific Statement From the American Heart Association

One in 4 Americans >40 years of age takes a statin to reduce the risk of myocardial infarction, ischemic stroke, and other complications of atherosclerotic disease. The most effective statins produce a mean reduction in low-density lipoprotein cholesterol of 55% to 60% at the maximum dosage, and 6 of the 7 marketed statins are available in generic form, which makes them affordable for most patients. Primarily using data from randomized controlled trials, supplemented with observational data where necessary, this scientific statement provides a comprehensive review of statin safety and tolerability. The review covers the general patient population, as well as demographic subgroups, including the elderly, children, pregnant women, East Asians, and patients with specific conditions such as chronic disease of the kidney and liver, human immunodeficiency viral infection, and organ transplants. The risk of statin-induced serious muscle injury, including rhabdomyolysis, is <0.1%, and the risk of serious hepatotoxicity is ≈0.001%. The risk of statin-induced newly diagnosed diabetes mellitus is ≈0.2% per year of treatment, depending on the underlying risk of diabetes mellitus in the population studied. In patients with cerebrovascular disease, statins possibly increase the risk of hemorrhagic stroke; however, they clearly produce a greater reduction in the risk of atherothrombotic stroke and thus total stroke, as well as other cardiovascular events. There is no convincing evidence for a causal relationship between statins and cancer, cataracts, cognitive dysfunction, peripheral neuropathy, erectile dysfunction, or tendonitis. In US clinical practices, roughly 10% of patients stop taking a statin because of subjective complaints, most commonly muscle symptoms without raised creatine kinase. In contrast, in randomized clinical trials, the difference in the incidence of muscle symptoms without significantly raised creatinine kinase in statin-treated compared with placebo-treated participants is <1%, and it is even smaller (0.1%) for patients who discontinued treatment because of such muscle symptoms. This suggests that muscle symptoms are usually not caused by pharmacological effects of the statin. Restarting statin therapy in these patients can be challenging, but it is important, especially in patients at high risk of cardiovascular events, for whom prevention of these events is a priority. Overall, in patients for whom statin treatment is recommended by current guidelines, the benefits greatly outweigh the risks.

Explaining Ethnic Variability of Transporter Substrate Pharmacokinetics in Healthy Asian and Caucasian Subjects with Allele Frequencies of OATP1B1 and BCRP: A Mechanistic Modeling Analysis

Background

Ethnic variability in the pharmacokinetics of organic anion transporting polypeptide (OATP) 1B1 substrates has been observed, but its basis is unclear. A previous study hypothesizes that, without applying an intrinsic ethnic variability in transporter activity, allele frequencies of transporters cannot explain observed ethnic variability in pharmacokinetics. However, this hypothesis contradicts the data collected from compounds that are OATP1B1 substrates but not breast cancer resistance protein (BCRP) substrates.

Objective

The objective of this study is to evaluate a hypothesis that is physiologically reasonable and more consistent with clinical observations.

Methods

We evaluated if allele frequencies of two transporters (OATP1B1 and BCRP) are key contributors to ethnic variability. In this hypothesis, the same genotype leads to the same activity independent of ethnicity, in contrast to the previous hypothesis of intrinsic ethnic variability in OATP1B1 activity. As a validation, we perform mechanistic pharmacokinetic modeling for SLCO1B1 (encoding OATP1B1) and ABCG2 (encoding BCRP) genotyped pharmacokinetic data from 18 clinical studies with healthy Caucasian and/or Asian subjects.

Results

Simulations based on the current hypothesis reasonably describe SLCO1B1 and ABCG2 genotyped pharmacokinetic time course data for five transporter substrates (atorvastatin, pitavastatin, pravastatin, repaglinide, and rosuvastatin) in Caucasian and Asian populations.

Conclusion

This hypothesis covers the observations that can (e.g., ethnic differences in rosuvastatin pharmacokinetics) or cannot (e.g., lack of differences for pitavastatin pharmacokinetics) be explained by the previous hypothesis. It helps to characterize sources of ethnic variability and provides a foundation for predicting ethnic variability in transporter substrate pharmacokinetics.

Electronic supplementary material

The online version of this article (doi:10.1007/s40262-017-0568-7) contains supplementary material, which is available to authorized users.

Efficacy and Safety of Pitavastatin in Children and Adolescents with Familial Hypercholesterolemia in Japan and Europe

Aim: Children with Familial Hypercholesterolemia (FH) are widely prescribed statins, and it has been suggested that the effects of statins differ among ethnicities. We compared the efficacy and safety of pitavastatin in children and adolescents with FH in clinical trials conducted in Japan and Europe.

Methods: Low-density lipoprotein cholesterol (LDL-C) reductions, adjusted for confounding factors, and safety were compared between the studies in Japan and Europe. In the Japanese study, 14 males with heterozygous FH, aged 11.8 ± 1.6 years, were randomized to 52-week double-blind treatment with 1 or 2 mg/day pitavastatin. In the European study, 106 children and adolescents with high risk hyperlipidemia (103 heterozygous FH), aged 10.6 ± 2.9 years, were randomized to 12-week double-blind treatment with 1, 2 or 4 mg/day pitavastatin or placebo; 84 of these patients and 29 new patients participated in a 52-week open-label extension study.

Results: Age, body weight and baseline LDL-C were identified as factors influencing LDL-C reduction. There were no significant differences in the adjusted mean percentage reduction in LDL-C in Japanese and European children by pitavastatin (24.5% and 23.6%, respectively at 1 mg/day and 33.5% and 30.8%, respectively at 2 mg/day). Pitavastatin was well tolerated without any difference in the frequency or nature of adverse events between the treatment groups, or between the studies.

Conclusion: There were no significant differences between the efficacy or safety of pitavastatin in Japanese and European children and adolescents with FH, suggesting no relevant ethnic differences in the safety or efficacy of pitavastatin.

Racial Differences in the Cholesterol-Lowering Effect of Statin

Statin treatment to reduce low-density lipoprotein cholesterol (LDL-C) is associated with the prevention of cardiovascular events in Western patients. Similar results have been reported in studies conducted in Japan. However, the dose of statins and the degree of LDL-C reduction achieved with statins are different between Asian and Western patients. In addition, there are limited data regarding racial differences in response to statins. In this review, racial differences between Asians and Westerners in response to statins are described.

Clinical benefits of pitavastatin: focus on patients with diabetes or at risk of developing diabetes

Despite attaining LDL-cholesterol targets, many patients with diabetes remain at risk of developing cardiovascular events. In addition, treatment with statins has been associated with a slight but significant increased risk of development of diabetes, particularly with high-intensity statins. Pitavastatin is a moderate- to high-intensity statin that effectively reduces LDL-cholesterol levels. Pitavastatin provides a sustained increase of HDL-cholesterol levels that may exhibit a neutral or positive effect on glucose metabolism, may not increase the risk of new-onset diabetes, may exhibit positive effects on renal function and urinary albumin excretion and the risk of drug–drug interactions is low. Therefore, it seems that pitavastatin should preferentially be considered in the treatment of dyslipidemia in diabetic patients or at risk of developing diabetes.

Ethnic variability in the expression of hepatic drug transporters: absolute quantification by an optimized targeted quantitative proteomic approach

Hepatic OATPs 1B1, 1B3 and 2B1, as well as P-gp, play important roles in regulating liver uptake and biliary excretion of drugs. The intrinsic ethnic variability in OATP1B1-mediated hepatic uptake of statins has been proposed to underlie the ethnic variability in plasma exposures of statins between Caucasians and Asians. Using a targeted quantitative proteomic approach, we determined hepatic protein concentrations of OATP1B1, OATP1B3, OATP2B1, P-gp, and PMCA4 (a housekeeping protein) in a panel of human livers (n = 141) and compared protein expression across Caucasian, Asian, African-American, and unidentified donors. Using an optimized protocol that included sodium deoxycholate as a membrane protein solubilizer, the hepatic protein expression levels (mean ± S.D.) of these transporters across all livers were determined to be 15.0 ± 6.0, 16.1 ± 8.1, 4.1 ± 1.3, 0.6 ± 0.2, and 2.4 ± 1.0 fmol/μg of total membrane protein, respectively. The scaling factor was 3.5 mg of total membrane protein in 100 mg of wet liver tissue. OATP1B1 protein expression was significantly associated with the c.388A>G (rs2306283, N130D) single nucleotide polymorphism. When compared across ethnicity, the hepatic expression levels of OATP1B1 and OATP1B3 were unexpectedly higher in Asians relative to Caucasians, suggesting that hepatic OATP expression alone does not explain the increased systemic statin levels in Asians compared with Caucasians. These findings may help improve physiologically based pharmacokinetic modeling to predict statin pharmacokinetic profiles and enable extrapolation of pharmacokinetic data of OATP substrates across ethnic groups.

Evaluation of the pharmacokinetics and drug interactions of the two recently developed statins, rosuvastatin and pitavastatin

INTRODUCTION

Statins are the cornerstone of lipid-lowering therapy to reduce the risk of coronary heart disease. Rosuvastatin and pitavastatin are the two recently developed statins with less potential for drug interaction resulting in improved safety profiles.

AREAS COVERED

This review summarizes the pharmacokinetics and drug interactions of rosuvastatin and pitavastatin. The materials reviewed were identified by searching PubMed for publications using 'rosuvastatin', 'pitavastatin', 'statins', 'pharmacokinetics' and 'drug interaction' as the search terms.

EXPERT OPINION

Rosuvastatin and pitavastatin have favorable pharmacokinetic and safety profiles as their disposition does not depend on or is only marginally influenced by cytochrome P450 (CYP) enzymes, thus potentially reducing the risk of drug-drug interactions of these two statins with other drugs known to inhibit CYP enzymes. However, drug transporters play a significant role in the disposition of rosuvastatin and pitavastatin and drug interactions may occur through these. Genetic polymorphisms in drug transporters may also affect the pharmacokinetics, drug interactions and/or the lipid-lowering effect of these statins to a different extent.

Ethnic variability in the plasma exposures of OATP1B1 substrates such as HMG-CoA reductase inhibitors: a kinetic consideration of its mechanism

Because the plasma exposure levels of rosuvastatin in Asians are generally twice those in Caucasians, the starting dose for Asians in the United States is set to half of that for non-Asians. However, the precise role of ethnicity in the clearance of rosuvastatin has not yet been clarified. This review focuses on ethnic variability in the clinical pharmacokinetics of 3-hydroxy-3-methylglutaryl co-enzyme A (HMG-CoA) reductase inhibitors (statins) and angiotensin II receptor antagonists. The mechanisms of such variability are discussed quantitatively, with building a hypothetical model for pravastatin, and validated against other statins. Our analyses suggest that the ethnic variability in the plasma exposure of statins cannot be explained only by the difference in the allele frequencies of organic anion-transporting polypeptide (OATP)1B1 and breast cancer resistance protein (BCRP), and the intrinsic ethnic variability in the activity of OATP1B1 (the ratio of Japanese/Caucasians is 0.584) must be considered. Further work and validation with additional data will clarify the applicability of this model to other OATP1B1 substrates.

Single- and multiple-dose pharmacokinetics, safety and tolerability of zibotentan (ZD4054) in Chinese men with advanced solid tumors

PURPOSE

The endothelin axis and the endothelin A (ET(A)) receptor have been implicated in tumor development and bone metastasis. This study aimed to investigate the pharmacokinetic (PK) and safety profiles of the specific ET(A) receptor antagonist, zibotentan, in elderly, male Chinese patients with advanced solid tumors. The PK data generated in these Chinese patients were further compared with those previously reported in Japanese and Caucasian patient populations.

METHODS

In this Phase I, open-label study, patients received a single dose of zibotentan 10 mg on Day 1, followed by a 72-h washout period and 12 consecutive days of once-daily zibotentan 10 mg.

RESULTS

Fifteen patients received at least one dose of zibotentan 10 mg. Exposure was demonstrated in all patients and the PK profiles following single dosing and multiple dosing showed relatively rapid absorption, decline in a monophasic manner, a modest amount of accumulation, and relatively low apparent clearance and volume of distribution. Zibotentan was well tolerated with no new safety concerns. Adverse events reported in >1 patient were pyrexia (n = 4), constipation (n = 3), headache (n = 3) and peripheral edema (n = 2). Comparative analysis found no evidence of significant differences in zibotentan exposure between the Chinese patients in our study, and the previous Japanese and Caucasian studies.

CONCLUSIONS

The PK and safety profiles of zibotentan determined in this Chinese patient population are similar to those previously reported. Our findings suggest no clinically relevant inter-ethnic differences in zibotentan disposition between the patient populations analyzed.