Modelling of atorvastatin pharmacokinetics and the identification of the effect of a BCRP polymorphism in the Japanese population

Population Pharmacokinetics of Atorvastatin in High-Altitude and Plain Patients with Hyperlipidemic

The pharmacokinetic (PK) characteristics of drugs were altered under high-altitude hypoxia. We aim to describe the population PK of atorvastatin (ATV) to identify patient characteristics that are predictive of variability in the PK parameters of the ATV and investigate the effects of high-altitude hypoxia on the blood concentration of ATV in patients with hyperlipidemia. A total of 160 plasma concentrations were collected from 40 patients with hyperlipidemia in plateau areas and 40 in plain areas. The population pharmacokinetic model of patients with hyperlipidemia in plateau and plain areas of China was established by a nonlinear mixed-effects model. The PK of ATV were described by a 1-compartment model with first-order elimination. The main PK parameters of ATV were the first-order absorption rate (0.76 hour-1 fixed); clearance (174.22 L/h) and apparent volume of distribution (1119.62 L). The values of area and age were identified as significant covariates for the clearance, area, age, and urea for the volume of distribution. The steady-state peak concentration in the plateau area was higher than that in the plain area. This study may suggest dose reduction is necessary for patients with hyperlipidemia in high altitudes.

Atorvastatin-associated myotoxicity: A toxicokinetic review of pharmacogenetic associations to evaluate the feasibility of precision pharmacotherapy

Atorvastatin (ATV) and other statins are highly effective in reducing cholesterol levels. However, in some patients, the development of drug-associated muscle side effects remains an issue as it compromises the adherence to treatment. Since the toxicity is dose-dependent, exploring factors modulating pharmacokinetics (PK) appears fundamental. The purpose of this review aims at reporting the current state of knowledge about the singular genetic susceptibilities influencing the risk of developing ATV muscle adverse events through PK modulations. Multiple single nucleotide polymorphisms (SNP) in efflux (ABCB1, ABCC1, ABCC2, ABCC4 and ABCG2) and influx (SLCO1B1, SLCO1B3 and SLCO2B1) transporters have been explored for their association with ATV PK modulation or with statin-related myotoxicities (SRM) development. The most convincing pharmacogenetic association with ATV remains the influence of the rs4149056 (c.521 T > C) in SLCO1B1 on ATV PK and pharmacodynamics. This SNP has been robustly associated with increased ATV systemic exposure and consequently, an increased risk of SRM. Additionally, the SNP rs2231142 (c.421C > A) in ABCG2 has also been associated with increased drug exposure and higher risk of SRM occurrence. SLCO1B1 and ABCG2 pharmacogenetic associations highlight that modulation of ATV systemic exposure is important to explain the risk of developing SRM. However, some novel observations credit the hypothesis that additional genes (e.g. SLCO2B1 or ABCC1) might be important for explaining local PK modulations within the muscle tissue, indicating that studying the local PK directly at the skeletal muscle level might pave the way for additional understanding.

ABCG2 and SLCO1B1 gene polymorphisms in the Croatian population

BACKGROUND

Organic anion-transporting polypeptide 1B1 (OATP1B1) and the ATP-binding cassette subfamily G member 2, ABCG2, are important transporters involved in the transport of endogenous substrates and xenobiotics, including drugs. Genetic polymorphisms of these transporters have effect on transporter activity. There is significant interethnic variability in the frequency of allele variants.

AIM

To determined allele and genotype frequencies of ABCG2 and SLCO1B1 genes in Croatian populations of European descent.

SUBJECTS AND METHODS

A total of 905 subjects (482 women) were included. Genotyping for ABCG2 c.421C > A (rs2231142) and for SLCO1B1 c.521T > C (rs4149056), was performed by real-time polymerase chain reaction (PCR) using TaqMan^® DME Genotyping Assays.

RESULTS

For ABCG2 c.421C > A, the frequency of CC, CA and AA genotypes was 81.4%, 17.8% and 0.8% respectively. The frequency of variant ABCG2 421 A allele was 9.7%. For SLCO1B1 c.521T > C, the frequency of TT, TC and CC genotypes was 61.7%, 34.8% and 3.5% respectively. The frequency of variant SLCO1B1 521 C allele was 20.9%.

CONCLUSION

The frequency of the ABCG2 and SLCO1B1 allelic variants and genotypes in the Croatian population is in accordance with other European populations. Pharmacogenetic analysis can serve to individualise drug therapy and minimise the risk of developing adverse drug reactions.

Atorvastatin population pharmacokinetics in a real-life setting: Influence of genetic polymorphisms and association with clinical response

The purpose of this study was to investigate the potential clinical relevance of estimating the apparent clearance (CL/F) of atorvastatin through population pharmacokinetic (PopPK) modeling with samples collected in a real-life setting in a cohort of ambulatory patients at risk of cardiovascular disease by using an opportunistic sampling strategy easily accessible in clinical routine. A total of 132 pharmacokinetic (PK) samples at a maximum of three visits were collected in the 70 included patients. The effects of demographic, genetic, and clinical covariates were also considered. With the collected data, we developed a two-compartment PopPK model that allowed estimating atorvastatin CL/F relatively precisely and considering the genotype of the patient for SLCO1B1 c.521T>C single-nucleotide polymorphism (SNP). Our results indicate that the estimation of the CL/F of atorvastatin through our PopPK model might help in identifying patients at risk of myalgia. Indeed, we showed that a patient presenting a CL/F lower than 414.67 L h-1 is at risk of suffering from muscle discomfort. We also observed that the CL/F was correlated with the efficacy outcomes, suggesting that a higher CL/F is associated with a better drug efficacy (i.e., a greater decrease in total and LDL-cholesterol levels). In conclusion, our study demonstrates that PopPK modeling can be useful in daily clinics to estimate a patient' atorvastatin clearance. Notifying the clinician with this information can help in identifying patients at risk of myalgia and gives indication about the potential responsiveness to atorvastatin therapy.

Prevalence of dyslipidemia and gene polymorphisms of ABCB1 and SLCO1B1 in Han, Uygur, Kazak, Hui, Tatar, Kirgiz, and Sibe populations with coronary heart disease in Xinjiang, China

Background

Dyslipidemia is a predisposing factor for coronary heart disease (CHD). High-intensity statin therapy is recommended as secondary prevention. ABCB1 and SLCO1B1 genes influence the efficacy and safety of statins. Xinjiang is a multi-ethnic area; however, little is known about the prevalence of dyslipidemia and gene polymorphisms of ABCB1 and SLCO1B1 in minority groups with CHD.

Objective

To measure levels of lipid and apolipoprotein and the prevalence of dyslipidemia and gene polymorphisms of ABCB1, SLCO1B1 in Han, Uygur, Kazak, Hui, Tatar, Kirgiz, and Sibe populations with CHD in Xinjiang.

Methods

This descriptive retrospective study compares lipid levels in ethnic groups using Kruskal-Wallis test or analysis of variance. The study compared gene polymorphisms and the prevalence of dyslipidemia among different ethnic groups using the chi-square test. The lipid profiles in plasma were measured before lipid-lowering therapy using commercially available kits. Genotyping of SLCO1B1 and ABCB1 variants was performed using sequencing by hybridization.

Results

A total of 2218 patients were successfully screened, including 1044 Han, 828 Uygur, 113 Kazak, 138 Hui, 39 Tatar, 36 Kirgiz, and 20 Sibe patients. The overall mean age was 61.8 ± 10.8 years, and 72.5% of participants were male. Dyslipidemia prevalence in these ethnic groups was 42.1, 49.8, 52.2, 40.6, 48.7, 41.7, and 45.0%, respectively. The prevalence of dyslipidemia, high total cholesterol (TC), high triglycerides (TG), and high low density lipoprotein cholesterol (LDL-C) differed significantly among the groups (P = 0.024; P < 0.001; P < 0.001; P < 0.001, respectively). For the Han group, high LDL-C, high TC, and high TG prevalence differed significantly by gender (P = 0.001, P = 0.022, P = 0.037, respectively). The prevalence of high TC, high TG, and low high density lipoprotein cholesterol (HDL-C) differed significantly by gender in the Uygur group (P = 0.006, P = 0.004, P < 0.001, respectively). The prevalence of high TC in Hui patients significantly differed by gender (P = 0.043). These findings suggest that polymorphisms in ABCB1 and C3435T differ significantly across ethnicities (P < 0.001).

Conclusions

The prevalences of dyslipidemia, high TC, high TG, and high LDL-C in Han, Uygur, Kazak, Hui, Tatar, Kirgiz, and Sibe CHD patients in Xinjiang differed concerning ethnicity. Ethnic, gender, and lifestyle were the key factors that affected the lipid levels of the population. The prevalence of polymorphisms of ABCB1 and C3435T significantly differed across ethnicities. These findings will aid the selection of precision lipid-lowering medications and prevention and treatment of CHD according to ethnicity in Xinjiang.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-021-01544-3.

Drug-drug-gene interactions as mediators of adverse drug reactions to diclofenac and statins: a case report and literature review

Concomitant treatment with drugs that inhibit drug metabolising enzymes and/or transporters, such as commonly prescribed statins and nonsteroidal anti-inflammatory drugs (NSAIDs), has been associated with prolonged drug exposure and increased risk of adverse drug reactions (ADRs) due to drug-drug interactions. The risk is further increased in patients with chronic diseases/comorbidities who are more susceptible because of their genetic setup or external factors. In that light, we present a case of a 46-year-old woman who had been experiencing acute renal and hepatic injury and myalgia over two years of concomitant treatment with diclofenac, atorvastatin, simvastatin/fenofibrate, and several other drugs, including pantoprazole and furosemide. Our pharmacogenomic findings supported the suspicion that ADRs, most notably the multi-organ toxicity experienced by our patient, may be owed to drug-drug-gene interactions and increased bioavailability of the prescribed drugs due to slower detoxification capacity and decreased hepatic and renal elimination. We also discuss the importance of CYP polymorphisms in the biotransformation of endogenous substrates such as arachidonic acid and their modulating role in pathophysiological processes. Yet even though the risks of ADRs related to the above mentioned drugs are substantially evidenced in literature, pre-emptive pharmacogenetic analysis has not yet found its way into common clinical practice.

Influence of Drug-Drug Interactions on the Pharmacokinetics of Atorvastatin and Its Major Active Metabolite ortho-OH-Atorvastatin in Aging People Living with HIV

Background

People living with HIV (PLWH) are aging and experience age-related physiological changes and comorbidities. Atorvastatin is a widely prescribed lipid-lowering agent metabolized by cytochrome P450 (CYP) 3A4, whose hepatocyte uptake is facilitated by organic anion transporting polypeptide (OATP) 1B1/1B3. Inhibition or induction of this enzyme and hepatic transporter can increase or decrease atorvastatin exposure, respectively.

Objective

This study aimed to describe the pharmacokinetic profile of atorvastatin and its major metabolite, and to evaluate drug–drug interactions (DDIs) with antiretrovirals (ARVs).

Methods

The atorvastatin pharmacokinetic profile was best described by a two-compartment model with first-order absorption and elimination. Metabolite concentrations were described by considering both linear metabolism from atorvastatin and presystemic metabolism. The influence of demographic and clinical covariates on drug and metabolite pharmacokinetics was assessed using NONMEM^®. Model-based simulations were performed to evaluate the magnitude of DDIs with ARVs.

Results

Full pharmacokinetic profiles (98 atorvastatin + 62 o-OH-atorvastatin concentrations) and sparse concentrations (78 and 53 for atorvastatin and o-OH-atorvastatin, respectively) were collected in 59 PLWH. Interindividual variability was high. The coadministration of boosted ARVs decreased atorvastatin clearance by 58% and slowed down o-OH-atorvastatin formation by 88%. Atorvastatin clearance increased by 78% when coadministered with CYP3A4 inducers. Simulations revealed a 180% increase and 44% decrease in atorvastatin exposure (area under the curve) in the presence of ARVs with inhibiting and inducing properties, respectively.

Conclusion

This study showed an important interindividual variability in atorvastatin pharmacokinetics that remains largely unexplained after the inclusion of covariates. Since boosted ARVs double atorvastatin exposure, the initial dosage might be reduced by half, and titrated based on individual clinical targets.

Electronic supplementary material

The online version of this article (10.1007/s40262-020-00876-0) contains supplementary material, which is available to authorized users.

Assessment of Transporter Polymorphisms as a Factor in a BCRP Drug Interaction Study With Lanabecestat

Lanabecestat is a human β-site amyloid precursor protein-cleaving enzyme 1 inhibitor in development to slow disease progression in patients with early Alzheimer's disease. The study evaluated the breast cancer resistance protein (BCRP) inhibition potential of lanabecestat on the pharmacokinetics (PK) of rosuvastatin, a probe for BCRP activity, in healthy white subjects who were not carriers of SLCO1B1 (c.521T>C), not homozygotes for ABCG2 (c.421C>A or c.34G>A), and not heterozygotes of ABCG2 (c.421C>A and c.34G>A). The safety of lanabecestat + rosuvastatin, the effects of rosuvastatin on the PK of lanabecestat, and the effects of multiple genetic polymorphisms on rosuvastatin exposure were assessed. Geometric mean ratios of the maximum observed rosuvastatin concentration (C_max ), area under the rosuvastatin concentration-versus-time curve (AUC) from time 0 to infinity, and time of maximum observed drug concentration (t_max ) when rosuvastatin was administered alone and with lanabecestat were contained within 0.8-1.25, as were lanabecestat AUC at steady state and t_max at steady state when lanabecestat was administered alone or with rosuvastatin. Lanabecestat C_max at steady state increased 8% in the presence of rosuvastatin. Except for an approximately 80% increase of rosuvastatin AUC (P < .05) in the heterozygotes of ABCG2 c.421C>A relative to the CC genotype, there were no statistically significant associations between rosuvastatin exposure and polymorphisms assessed. Lanabecestat + rosuvastatin was associated with few treatment-emergent adverse events, all of which resolved and were mild. Lanabecestat does not meaningfully impact BCRP activity; therefore, restriction of concomitant administration with BCRP substrates, such as rosuvastatin, may be unnecessary.

UHPLC-MS/MS assay for simultaneous determination of amlodipine, metoprolol, pravastatin, rosuvastatin, atorvastatin with its active metabolites in human plasma, for population-scale drug-drug interactions studies in people living with HIV

Thanks to highly active antiretroviral treatments, HIV infection is now considered as a chronic condition. Consequently, people living with HIV (PLWH) live longer and encounter more age-related chronic co-morbidities, notably cardiovascular diseases, leading to polypharmacy. As the management of drug-drug interactions (DDIs) constitutes a key aspect of the care of PLWH, the magnitude of pharmacokinetic DDIs between cardiovascular and anti-HIV drugs needs to be more thoroughly characterized. To that endeavour, an UHPLC-MS/MS bioanalytical method has been developed for the simultaneous determination in human plasma of amlodipine, metoprolol, pravastatin, rosuvastatin, atorvastatin and its active metabolites. Plasma samples were subjected to protein precipitation with methanol, followed by evaporation at room temperature under nitrogen of the supernatant, allowing to attain measurable plasma concentrations down to sub-nanogram per milliliter levels. Stable isotope-labelled analytes were used as internal standards. The five drugs and two metabolites were analyzed using a 6-min liquid chromatographic run coupled to electrospray triple quadrupole mass spectrometry detection. The method was validated over the clinically relevant concentrations ranging from 0.3 to 480 ng/mL for amlodipine, atorvastatin and p-OH-atorvastatin, and 0.4 to 480 ng/mL for pravastatin, 0.5 to 480 ng/mL for rosuvastatin and o-OH-atorvastatin, and 3 to 4800 ng/mL for metoprolol. Validation performances such as trueness (95.4-110.8%), repeatability (1.5-13.4%) and intermediate precision (3.6-14.5%) were in agreement with current international recommendations. Accuracy profiles (total error approach) were lying within the limits of ±30% accepted in bioanalysis. This rapid and robust UHPLC-MS/MS assay allows the simultaneous quantification in plasma of the major currently used cardiovascular drugs and offers an efficient analytical tool for clinical pharmacokinetics as well as DDIs studies.

Utilization of data below the analytical limit of quantitation in pharmacokinetic analysis and modeling: promoting interdisciplinary debate

Traditionally, bioanalytical laboratories do not report actual concentrations for samples with results below the LOQ (BLQ) in pharmacokinetic studies. BLQ values are outside the method calibration range established during validation and no data are available to support the reliability of these values. However, ignoring BLQ data can contribute to bias and imprecision in model-based pharmacokinetic analyses. From this perspective, routine use of BLQ data would be advantageous. We would like to initiate an interdisciplinary debate on this important topic by summarizing the current concepts and use of BLQ data by regulators, pharmacometricians and bioanalysts. Through introducing the limit of detection and evaluating its variability, BLQ data could be released and utilized appropriately for pharmacokinetic research.

Quantitative Analysis of the Transporter-Mediated Drug-Drug Interaction Between Atorvastatin and Rifampicin Using a Stable Isotope-IV Method

This study aims to investigate the drug-drug interactions (DDIs) between orally administered atorvastatin (ATV) and rifampicin (RIF) in rats. The isotope-IV method was used for the analysis of the increased systemic exposure (AUC_po) of ATV, in which a small amount of deuterium-labeled ATV (ATV-d5) was intravenously injected after oral administration of ATV. By assuming ATV-d5 showed same pharmacokinetic properties with ATV, this method enabled to calculate the systemic clearance (CL_tot) and the oral bioavailability (F_oral) of ATV for each individual rat in a single experiment. RIF was orally pretreated to rats to inhibit the organic anion transporting polypeptide 1B1 (OATP1B1). From the analysis using pharmacokinetic parameters in each rat, it was revealed that the AUC_po of ATV increased depending on the plasma level of RIF, showing that the interindividual difference in the absorption of RIF caused the large variability in the extent of DDI. Furthermore, it was indicated that not only the decrease in CL_tot but also the increase in F_oral caused the significant increase in the AUC_po of ATV. In conclusion, the isotope-IV method possesses various advantages over the conventional method for the analysis of DDIs which affects both absorption and elimination processes of oral drugs.