Eun Sil Oh

Effect of HMGCR Variant Alleles on Low-Density Lipoprotein Cholesterol—Lowering Response to Atorvastatin in Healthy Korean Subjects

The investigators quantified the relationship between the genetic polymorphism of HMGCR (3‐hydroxy‐3‐methylglutaryl coenzyme A reductase) and the low‐density lipoprotein cholesterol (LDL‐C)–lowering effects of atorvastatin in a prospective clinical study. Twenty‐four healthy participants were grouped into HMGCR rs3846662 GG (n = 13) and AA (n = 11) genotypes and given atorvastatin (20 mg/d) for 14 days. Serum levels of LDL‐C, high‐density lipoprotein cholesterol, total cholesterol, triglycerides, and creatinine kinase (CK) were measured before (day 1) and 7, 13, 14, 15, 16, 21, and 28 days after dosing initiation. Blood samples for pharmacokinetics were taken on days 14 through 16. The levels of LDL‐C in the GG group were significantly higher than in the AA group at all observation times, with mean differences of 18% to 33% (P < .05). The area under the LDL‐C—time curve and the minimum value of LDL‐C in the GG group were 24% and 23% higher than in the AA group, respectively (P < .01). There was no significant difference in other lipids, CK, and pharmacokinetic parameters. The HMGCR rs3846662 GG genotype was quantitatively documented to be a significant determinant for higher LDL‐C level in basal state and possibly in response to atorvastatin.

The UGT1A3*2 polymorphism affects atorvastatin lactonization and lipid-lowering effect in healthy volunteers.

Objective We investigated whether the UGT1A3 polymorphisms play an important role in interindividual variations in atorvastatin lactonization and lipid-lowering effect. Methods Twenty-three healthy volunteers were administered atorvastatin 20 mg once daily for 14 days. Serum levels of lipids were measured before and 7, 13, 14, 15, 21, and 28 days after the initial dosing. Blood samples for pharmacokinetic analysis were collected up to 48 h after the last dose. Results The UGT1A3*2 and UGT1A1*28 polymorphism had a perfect linkage in the participants. Lactone formation was significantly higher in the UGT1A3*2 carriers. The areas under the curve of atorvastatin lactone and 2-hydroxyatorvastatin lactone were 72 and 160% higher in individuals with UGT1A3*2/*2 than UGT1A3*1/*1, respectively. The maximum percent decreases in the total and the low-density lipoprotein cholesterol from baseline in UGT1A3*2 carriers were 29 and 18% less than the UGT1A3*2 noncarriers, respectively. Conclusion The UGT1A3*2 polymorphism is correlated with increased atorvastatin lactonization and may affect its lipid-lowering effect.

Influence of ABCC2, SLCO1B1, and ABCG2 polymorphisms on the pharmacokinetics of olmesartan.

Abstract: This study was designed to determine whether genetic polymorphisms of multidrug-resistant protein 2 (ABCC2), organic anion transporting polypeptide 1B1 (SLCO1B1), and breast cancer resistance protein (ABCG2) have an effect on olmesartan pharmacokinetics in Korean subjects. Sixty-eight healthy male volunteers who participated in previous pharmacokinetics studies of olmesartan medoxomil (single dose, 20 mg or 40 mg) were enrolled. All subjects were analyzed and grouped according to the genotypes of ABCC2, SLCO1B1, and ABCG2. The dose-normalized peak plasma concentration (Cmax) and area under the plasma concentration–time curve (AUCt) values were analyzed. The dose-normalized mean Cmax and AUCt in the ABCC2 -24CT genotype group were higher than those in the -24CC genotype group [Cmax,dn: CT 26.1 ± 6.5 (ng/mL)/mg versus CC 22.1 ± 6.7 (ng/mL)/mg, P = 0.010, AUCt,dn: CT 178.7 ± 45.6 (hr·ng−1·mL−1)/mg versus CC 149.9 ± 39.8 (hr·ng−1·mL−1)/mg, P = 0.010]. The difference in AUCt,dn between the ABCC2 -1549GG and -1549GA genotype groups was statistically significant [GG 149.0 ± 41.0 (hr·ng−1·mL−1)/mg versus. GA 174.1 ± 43.3 (hr·ng−1·mL−1)/mg, P = 0.019]. No significant differences were observed for any other single nucleotide polymorphism in ABCC2, SLCO1B1, or ABCG2. The ABCC2 -24CC genotype group exhibited lower systemic exposure of olmesartan than the -24CT genotype group, whereas no significant differences were observed in the other transporter genotype groups.

Influence of hepatic dysfunction on the pharmacokinetics and safety of fimasartan.

Abstract: This study was designed to assess the pharmacokinetics (PK) and safety of fimasartan, an angiotensin II type 1 receptor blocker, in hepatic impairment patients as compared with healthy subjects. An open-label, single-dose, parallel study was conducted in 6 healthy male volunteers and 12 subjects with hepatic impairment. Healthy subjects were matched with hepatic dysfunction patients on the basis of age, gender, and body weight. After a single 120-mg oral administration of fimasartan, PK parameters and safety were analyzed between the hepatic dysfunction groups and healthy group. Compared with the healthy subjects, the geometric mean ratio and 90% confidence intervals for the maximum plasma concentration and the mean area under the plasma concentration–time curve from 0 to infinity (AUC)inf were 0.77 (0.24–2.47) and 1.11 (0.50–2.46), respectively, for the mild hepatic impairment and 6.55 (3.56–12.03) and 5.17 (4.19–6.37), respectively, for moderate hepatic impairment. However, there was no significant difference in time to peak plasma concentration (tmax) and elimination half-life, and there were no serious or severe adverse events in all subjects. Subjects with mild hepatic impairment exhibited similar bioavailability compared with healthy subjects, whereas subjects with moderate hepatic impairment seemed to exhibit a higher level of systemic exposure to fimasartan than healthy subjects. In addition, all subjects were tolerable with fimasartan.

Modeling of the LDL cholesterol-lowering effect of atorvastatin in Korean dyslipidemic patients and non-patient volunteers.

OBJECTIVE The aim of this study was to develop a longitudinal pharmacodynamic model describing the time-courses of low-density lipoprotein cholesterol (LDL) profiles during and after atorvastatin treatment in Korean dyslipidemic patients and non-patient volunteers. METHODS 15 dyslipidemic patients and 11 non-patient volunteers with no prior therapy participated in a parallel, 2-step dose escalation study. Subjects received atorvastatin doses ranging from 10 to 80 mg for 42 days (dyslipidemic patients) or 10 mg for 21 days (non-patient volunteers). Plasma samples were collected before and during the treatment period and up to 2 weeks after the last administration. A population pharmacodynamic model was built using the NONMEM software package. An indirect response model consisting of production in hepatocyte and elimination from plasma stimulated by atorvastatin described the LDL time-course. RESULTS The typical population value of the estimated dose producing 50% of maximal stimulation on LDL elimination (SD50) for dyslipidemic patients was 11.9 mg, which was about 6 times higher than that of non-patient volunteers (2.0 mg). CONCLUSION A longitudinal population pharmacodynamic model for the LDL-lowering effect of atorvastatin in both dyslipidemic patients and non-patient volunteers was developed. This could help guide optimal therapies according to the target population.

Awareness and attitude of the public toward personalized medicine in Korea

Objectives As personalized medicine (PM) is expected to greatly improve health outcomes, efforts have recently been made for its clinical implementation in Korea. We aimed to evaluate public awareness and attitude regarding PM. Methods We performed a self-administered questionnaire survey to 703 adults, who participated in the survey on a voluntary basis. The primary outcome measures included public knowledge, attitude, and acceptance of PM. We conducted multinomial multivariate logistic analysis for outcome variables with three response categories and performed multivariate logistic regression analyses for dichotomous outcome variables. Results Only 28% of participants had knowledge that genetic factors can contribute to inter-individual variations in drug response and the definition of PM (199 out of 702). Higher family income was correlated with greater knowledge concerning PM (OR = 3.76, p = 0.034). A majority of respondents preferred integrated pharmacogenomic testing over drug-specific testing and agreed to inclusion of pharmacogenomic testing in the national health examination (64% and 77%, respectively), but only 51% were willing to pay for it. Discussion Our results identify the urgent need for public education as well as the potential health disparities in access to PM. This study helps to frame policies for implementing PM in clinical practice.

Effects of clarithromycin on the pharmacokinetics of evogliptin in healthy volunteers

Evogliptin (DA‐1229), a novel dipeptidyl peptidase (DPP)‐4 inhibitor with high potency and selectivity, was approved in Korea for the treatment of type 2 diabetes. Preclinical studies suggest that it is metabolized by cytochrome (CYP) P450 isozymes. Based on these findings, a clinical study was designed to investigate the pharmacokinetic (PK) interaction of evogliptin with a CYP inhibitor, clarithromycin.

Pharmacokinetic interactions between glimepiride and rosuvastatin in healthy Korean subjects: does the SLCO1B1 or CYP2C9 genetic polymorphism affect these drug interactions?

To improve cardiovascular outcomes, dyslipidemia in patients with diabetes needs to be treated. Thus, these patients are likely to take glimepiride and rosuvastatin concomitantly. Therefore, this study aimed to evaluate the pharmacokinetic (PK) interactions between these two drugs in healthy males and to explore the effect of SLCO1B1 and CYP2C9 polymorphisms on their interactions in two randomized, open-label crossover studies. Glimepiride was studied in part 1 and rosuvastatin in part 2. Twenty-four participants were randomly assigned to each part. All subjects (n=24) completed part 1, and 22 subjects completed part 2. A total of 38 subjects among the participants of the PK interaction studies were enrolled in the genotype study to analyze their SLCO1B1 and CYP2C9 polymorphisms retrospectively (n=22 in part 1, n=16 in part 2). Comparison of the PK and safety of each drug alone with those of the drugs in combination showed that both glimepiride and rosuvastatin did not interact with each other and had tolerable safety profiles in all subjects. However, with regard to glimepiride PK, the SLCO1B1 521TC group had a significantly higher maximum plasma concentration (Cmax,ss) and area under the plasma concentration–time curve during the dose interval at steady state (AUCτ,ss) for glimepiride in combination with rosuvastatin than those for glimepiride alone. However, other significant effects of the SLCO1B1 or CYP2C9 polymorphism on the interaction between the two drugs were not observed. In conclusion, there were no significant PK interactions between the two drugs; however, the exposure to glimepiride could be affected by rosuvastatin in the presence of the SLCO1B1 polymorphism.

Pharmacokinetics, pharmacodynamics and safety of CKD-519, a CETP inhibitor, in healthy subjects

CKD-519 is a selective and potent cholesteryl ester transfer protein (CETP) inhibitor being developed for the treatment of dyslipidemia to raise high-density lipoprotein cholesterol. We investigated the safety, tolerability, pharmacokinetics, and pharmacodynamics of single doses of CKD-519 in healthy adult subjects. A randomized, double-blinded, placebo-controlled, single ascending dose study was performed. Eight healthy subjects were enrolled in each CKD-519 dose group (25, 50, 100, 200, or 400 mg) and randomized to CKD-519 (n=6) or matching placebo (n=2). CKD-519 reached the maximum plasma concentration (Cmax) at 5–6 h post-dose, and had a long terminal half-life ranging between 40–70 h. The area under the plasma concentration–time curve (AUC) and Cmax increased with the dose, however, Cmax and AUC normalized by dose decreased with each incremental dose. CETP activity decreased with dose, and the maximum decrease (63%–83%) was observed at 6–8 h post-dose. A sigmoid Emax model best described the relationship between CKD-519 plasma concentrations and CETP activity with an EC50 of 17.3 ng/mL. Overall, 11 adverse events (AEs) were observed. All AEs were mild or moderate in intensity, and resolved without any complications. There were no clinically significant effects on blood pressure. In conclusion, single doses of CKD-519 up to 400 mg were well tolerated and showed potent inhibition of CETP activity.

Effect of Ketoconazole on Lobeglitazone Pharmacokinetics in Korean Volunteers

PURPOSE Lobeglitazone, a peroxisome proliferator-activated receptor-γ agonist, is metabolized primarily by the cytochrome P450 (CYP) 3A4 isoenzyme. Individuals concomitantly taking lobeglitazone and a CYP3A4 inhibitor may experience some adverse effects secondary to increased systemic exposure to lobeglitazone. To address such potential concern, we evaluated the effects of ketoconazole, a prototypic CYP3A4 inhibitor, on the pharmacokinetic (PK) properties and associated adverse effects of lobeglitazone. METHODS A PK drug-drug interaction study was conducted in healthy individuals between 20 and 45 years old in a randomized, open-label, 2-way crossover design. Even though the PK study was performed on a single dose of lobeglitazone, multiple ketoconazole doses were given to ensure that the full extent of inhibition of CYP3A4 was maintained during the PK sampling. All study participants received a single oral dose of lobeglitazone 0.5 mg with or without 9 oral 200-mg doses of ketoconazole pretreatment twice daily. The primary PK parameter end points (AUC and Cmax) were estimated using noncompartmental analysis, and the 90% CIs for the geometric mean ratios (ratio of lobeglitazone and ketoconazole to lobeglitazone alone) were investigated. Tolerability (adverse events, vital signs, ECG, and laboratory tests) was also assessed. FINDINGS A total of 24 Korean men (mean age, 26 years; age range, 20-32 years; mean weight, 68 kg; weight range, 59-81 kg) completed the study and were evaluable for lobeglitazone PK properties and tolerability. The mean (SD) Cmax values of lobeglitazone with and without ketoconazole were 49 (7) ng/mL and 48 (6) ng/mL at 1.5 and 1.0 hours after dosing, respectively. The mean (SD) AUC∞ values were 532 (117) ng·h/mL and 405 (110) ng·h/mL, respectively. Although the Cmax was not significantly affected, the geometric mean ratio for AUC∞ was increased by a point estimate of 1.33 (90% CI, 1.23-1.44). A single oral administration of lobeglitazone 0.5 mg with or without ketoconazole pretreatment did not produce any clinically significant adverse effects on vital signs, 12-lead ECG profiles, or laboratory tests. IMPLICATIONS The administration of lobeglitazone, 0.5 mg alone or in combination with multiple doses of ketoconazole, was generally well tolerated. The systemic exposure of lobeglitazone was increased to a modest extent by pretreatment with 9 twice-daily doses of ketoconazole. Clinicaltrials.gov identifier: NCT01330563.