Jong-Lyul Ghim

Pharmacokinetic, Tolerability, and Bioequivalence Comparison of Three Different Intravenous Formulations of Recombinant Human Erythropoietin in Healthy Korean Adult Male Volunteers: An Open-Label, Randomized-Sequence, Three-Treatment, Three-Way Crossover Study

BACKGROUND Existing formulations of recombinant human erythropoietin (rhEPO) in Korea contain human serum albumin. To avoid the potential risk of infection by human serum albumin, a new albumin-free rhEPO has been developed. OBJECTIVE This study was conducted to characterize and compare the pharmacokinetic and safety profiles and the bioequivalence of a newly developed albumin-free rhEPO (Aropotin [TS Corporation, Seoul, South Korea]) with 2 existing rhEPO formulations (Espogen [LG Life Sciences, Seoul, South Korea]; Recormon [Roche, Basel, Switzerland]) with albumin in healthy Korean subjects. METHODS This was an open-label, randomized-sequence, 3-treatment, 3-way crossover study in which healthy, nonobese (+/-20% of ideal weight), male volunteers between the ages of 19 and 50 years were assigned to 1 of 2 dose levels (50 IU/kg or 100 IU/kg) of 3 formulations. Blood was collected over 32 hours and plasma rhEPO concentrations were determined using a validated enzyme immunoassay. There was a 14-day washout between periods. The pharmacokinetic parameters of the 3 formulations were compared using the bioequivalence criteria of the US Food and Drug Administration, which requires that the 90% CIs of the geometric mean ratios for AUC(0-t), AUC(0-infinity), and C(max) fall within 0.80 to 1.25. Tolerability was evaluated by physical examination with measurements of vital signs, clinical laboratory tests, and electrocardiogram. Subjects were followed up for 2 weeks after the last administration of study drug. RESULTS Twelve Korean male volunteers were enrolled and completed the study. Six subjects (mean [SD] age, 22.0 [1.7] years; weight, 63.3 [6.2] kg; height, 172.3 [3.5] cm) received a single 50 IU/kg IV bolus dose of study drug and the remaining 6 subjects (mean [SD] age, 23.7 [1.5] years; weight, 66.3 [4.8] kg; height, 174 [4.7] cm) received 100 IU/kg. After a single 50 IU/kg dose, the geometric mean ratio (90% CI) for Aropotin/Espogen was 1.04 (0.91-1.19) IU/L/h for AUC(0-t) and 1.02 (0.89-1.17) IU/L for C(max). The geometric mean ratio (90% CI) for Aropotin/Recormon was 1.01 (0.88-1.15) IU/L/h for AUC(0-t) and 1.01 (0.89-1.16) IU/L for C(max). After a single 100-IU/kg dose, the geometric mean ratio (90% CI) for Aropotin/ Espogen was 0.98 (0.86-1.13) IU/L/h for AUC(0-t) and 0.99 (0.87-1.13) IU/L for C(max). The geometric mean ratio (90% CI) for Aropotin/Recormon was 0.99 (0.861.14) IU/L/h for AUC(0-t) and 0.96 (0.84-1.10) IU/L for C(max). The most frequent adverse events (AEs) were 3 occurrences of elevated serum creatine phosphokinase and serum lactate dehydrogenase levels in the Recormon 100-IU/kg group (n = 3), 3 events of elevated serum lactate dehydrogenase levels in the Espogen 100-IU/kg group (n = 3), and 4 events of elevated serum total bilirubin levels in the Aropotin 100-IU/kg group (n = 3). All formulations were well tolerated with no serious AEs. CONCLUSION The new formulation of rhEPO met the regulatory criteria for bioequivalence in these healthy Korean adult male volunteers. All formulations were generally well tolerated.

Impact of CYP2D6, CYP3A5, CYP2C19, CYP2A6, SLCO1B1, ABCB1, and ABCG2 gene polymorphisms on the pharmacokinetics of simvastatin and simvastatin acid.

Objective The effects of various polymorphisms in cytochrome P450 (CYP) enzyme and transporter genes on the pharmacokinetics (PK) of simvastatin were evaluated in healthy Korean men. Methods Plasma concentration data for simvastatin and simvastatin acid were pooled from four phase I studies comprising 133 participants. The polymorphisms CYP2D6*4, CYP2D6*5, CYP2D6*14, CYP2D6*41, CYP3A5*3, CYP2C19*2, CYP2C19*3, CYP2A6*7, and CYP2A6*9; SLCO1B1 rs4149056, rs2306283, and rs4149015; ABCB1 rs1128503, rs2032582, and rs1045642; and ABCG2 rs2231142 were evaluated in each participant. Noncompartmental PK results were compared by genotype. Results CYP2D6*5 and CYP2D6*14 were found to be associated with a higher area under the curve (AUC) for simvastatin, whereas the AUC of simvastatin acid was significantly increased in patients with the SLCO1B1 rs4149056, ABCG2 rs2231142, and CYP2D6*41 allele variants. Patients with the CYP2D6*41 variant showed a higher peak serum concentration (Cmax) of both simvastatin and simvastatin acid. The SLCO1B1 rs4149056 and rs4149015 polymorphisms were associated with an increased AUC ratio (i.e. ratio of simvastatin acid to simvastatin), whereas the SLCO1B1 rs4149056 and CYP2D6*5 variants were related to a higher Cmax ratio. Conclusion The CYP2D6*5, CYP2D6*14, CYP2D6*41, CYP3A5*3, SLCO1B1 rs4149056 and rs4149015, and ABCG2 rs2231142 genetic polymorphisms are associated with the PK of both simvastatin and simvastatin acid. This could potentially be used as a basis for individualized simvastatin therapy by predicting the clinical outcomes of this treatment.

Evaluation of Pharmacokinetic and Pharmacodynamic Profiles and Tolerability After Single (2.5, 5, or 10 mg) and Repeated (2.5, 5, or 10 mg BID for 4.5 days) Oral Administration of Ivabradine in Healthy Male Korean Volunteers

BACKGROUND Ivabradine, a selective inhibitor of the pacemaker current in the sinoatrial node, has shown pure heart rate (HR)-reducing effects with anti-ischemic efficacy as well as improvement in heart failure outcomes. OBJECTIVE The purpose of this study was to explore pharmacokinetic (PK) and pharmacodynamic (PD) characteristics and tolerability in healthy male Korean volunteers, as well as to compare them with PK/PD profiles of white subjects. METHODS This was a randomized, double-blind, placebo-controlled Phase I study conducted in healthy male subjects. For each of the 3 dosing groups, 9 subjects were randomized to receive ivabradine and 3 to receive placebo. Subjects received a single oral dose of ivabradine 2.5, 5, or 10 mg and after a 3-day washout period, repeat doses of 2.5, 5, or 10 mg BID for 4.5 days. Blood and urine samples were collected over 72 hours during each period, and levels of ivabradine and its metabolite S18982 were determined by using validated LC-MS/MS, followed by noncompartmental PK analysis. For PD properties and tolerability, 24-hour Holter recordings were obtained: at baseline, after a single dose, after repeated doses, and after the last dose. Serial resting 12-lead ECG assessments were also performed throughout the study. RESULTS Forty-eight subjects were enrolled, and 45 completed the study. After single doses of 2.5, 5, and 10 mg, respective mean Cmax levels of ivabradine were 9, 15, and 39 ng/mL, and mean AUC0-last values were 30, 52, and 121 ng h/mL. At steady state, mean Cmax,ss levels were 11, 19, and 42 ng/mL, reached at a median Tmax of 0.67 hour for all 3 doses. The mean AUC0-τ levels were 43, 58, and 139 ng h/mL, respectively. The PK findings were linear with dose and time. Decreases in mean HR on both the Holter recordings and ECGs were observed in all of the ivabradine groups compared with placebo. After the repeated doses, mean decreases in HR were greater than those for the single doses for the same period. Statistically significant differences were observed between the 5- and 10-mg ivabradine groups and placebo. A total of 3 adverse events were reported in 2 subjects receiving ivabradine; both fully recovered without sequelae. CONCLUSIONS Single and repeated administration of ivabradine were generally well tolerated in these healthy male Korean volunteers. Ivabradine induced significant reductions in HR, especially at doses of 5 and 10 mg. PK/PD characteristics were similar to those found in white subjects, suggesting that the dose concentration-response relationship of ivabradine is similar between Korean and white subjects.

The pharmacokinetics of letrozole: association with key body mass metrics

PURPOSE To characterize the pharmacokinetics (PK) of letrozole by noncompartmental and mixed effect modeling analysis with the exploration of effect of body compositions on the PK. METHODS The PK data of 52 normal healthy male subjects with intensive PK sampling from two separate studies were included in this analysis. Subjects were given a single oral administration of 2.5 mg letrozole (Femara®), an antiestrogenic aromatase inhibitor used to treat breast cancer. Letrozole concentrations were measured using validated high-performance liquid chromatography with tandem mass spectrometry. PK analysis was performed using NONMEM® 7.2 with first-order conditional estimation with interaction method. The association of body composition (body mass index, soft lean mass, fat free mass, body fat mass), CYP2A6 genotype (*1/*1, *1/*4), and CYP3A5 genotype (*1/*1, *1/*3, *3/*3) with the PK of letrozole were tested. RESULTS A two-compartment model with mixed first and zero order absorption and first order elimination best described the letrozole concentration-time profile. Body weight and body fat mass were significant covariates for central volume of distribution and peripheral volume of distribution (Vp), respectively. In another model built using more readily available body composition measures, body mass index was also a significant covariate of Vp. However, no significant association was shown between CYP2A6 and CYP3A5 genetic polymorphism and the PK of letrozole in this study. CONCLUSION Our results indicate that body weight, body fat mass, body mass index are associated with the volume of distribution of letrozole. This study provides an initial step toward the development of individualized letrozole therapy based on body composition.

Pharmacokinetic Comparison of 2 Formulations of Anastrozole (1 mg) in Healthy Korean Male Volunteers: A Randomized, Single-Dose, 2-Period, 2-Sequence, Crossover Study

BACKGROUND Anastrozole is an aromatase inhibitor used to treat advanced breast cancer in postmenopausal women. A generic 1-mg tablet of anastrozole was recently developed. OBJECTIVE The study was designed to provide data to submit to Korean regulatory authorities to allow marketing of the test formulation. We evaluated the comparative bioavailability and tolerability of the test and reference formulations in healthy male adult volunteers. METHODS This single-dose, randomized, double-blind, 2-way crossover trial was conducted in the Clinical Trial Center at the Asan Medical Center (Seoul, Korea). A total of 24 healthy male Korean volunteers were enrolled. Subjects were randomized to receive 1 mg of the test or reference formulation, and pharmacokinetic (PK) parameters were measured. After a 3-week washout period, the other formulation was administered, and PK parameters were measured again. C(max) and AUC(last) were determined from blood samples obtained at 0.33, 0.67, 1, 1.5, 2, 3, 4, 6, 8, 12, 24, 48, 72, 96, 120, 168, and 216 hours after drug administration. The formulations were considered bioequivalent if the 90% CIs of the geometric mean ratios of test-to-reference formulations for AUC(last) and C(max) were within the bioequivalence limits of 0.8 to 1.25. Nonlinear mixed-effect modeling and Monte Carlo simulations for both formulations were also conducted, and the results were used to characterize and compare the PK properties. Safety profile and tolerability were assessed using measurements of vital signs, clinical chemistry tests, and interviews. RESULTS All enrolled subjects completed the study. A total of 8 adverse events (AEs) were reported (2 on test formulation, 6 on reference formulation) in 7 of 24 participants. These AEs were headache (n = 1), hordeolum (n = 1), and abnormal laboratory test values (n = 6). Both formulations were well tolerated, and there were no serious AEs. Both formulations were best described by a 2-compartment disposition model with lag phase. The 90% CIs of the geometric mean ratios of test formulation to reference formulation were 0.96 to 1.08 for C(max) and 0.93 to 1.0 for AUC(last). CONCLUSION The test and reference formulations had similar PK parameters and similar plasma concentration-time profiles. The test formulation of anastrozole met the Korean regulatory criteria (AUC and C(max)) for assuming bioequivalence. ClinicalTrials.gov identifier: NCT01105299.

Effect of voglibose on the pharmacokinetics of metformin in healthy Korean subjects.

OBJECTIVE The objective of this study was to evaluate the effects of voglibose on the pharmacokinetics of metformin. METHODS A randomized, open-label, two-way crossover study with a 7-day washout period was conducted. All subjects were given an oral dose of metformin with or without voglibose 3 x daily for 7 days. Plasma concentrations of metformin on day 7 were measured using high performance liquid chromatography (HPLC) with UV detection for pharmacokinetic assessment Vital signs and adverse events were monitored, and physical examinations and laboratory tests were conducted to evaluate safety. RESULTS 22 subjects completed the study. The geometric mean ratios for C(ss,max) of metformin (metformin plus voglibose vs. metformin only) were 0.98 (90% CI, 0.92 - 1.05; p > 0.05) and for AUC-τ, the ratio was 0.99 (90% CI, 0.92 - 1.06; p > 0.05). There were no significant differences in adverse drug reactions between metformin with and without voglibose. However, the incidence of adverse events was higher in period 1 than in period 2 (16 cases vs. 1 case, p < 0.001). CONCLUSIONS Co-administration of metformin and voglibose had no statistically or clinically significant effects on the pharmacokinetics of metformin in healthy subjects. The pharmacodynamic interaction study to evaluate the effect of metformin on the pharmacodynamics of voglibose is in progress.

Pharmacokinetic study of metformin to compare voglibose/metformin fixed-dose combination with coadministered voglibose and metformin.

The aim of this study was to compare the pharmacokinetic characteristics of metformin between a fixed-dose combination (FDC) of voglibose/metformin and co-administered individual voglibose and metformin tablets in healthy Korean volunteers under fasting conditions. A randomized, open-label, single-dose, two-treatment, two-way crossover study with a 7-day wash-out period was conducted. Plasma samples were collected for up to 24 hours and were analyzed for metformin using a validated liquid chromatography tandem mass-spectrometry (LC/MS). A non-compartmental method was used to calculate the pharmacokinetic parameters. Vital signs and adverse events were monitored, and physical examinations and laboratory tests were conducted to evaluate safety. In total, 28 subjects completed the study. The geometric mean ratio (GMR) and the 90% confidence interval (CIs) of Cmax and AUC0–t of metformin were 102.4 (94.5 – 111.0) and 107.1 (100.1 – 114.7), respectively. In total, 7 adverse drug reactions occurred in 4 subjects during the study; of these, 3 cases were from 3 subjects in the test treatment group, and 4 cases were from 3 subjects in the reference treatment group. All adverse drug reactions had been reported previously, and all subjects recovered fully without any sequelae. In conclusion, the pharmacokinetic profiles of metformin in two different study treatments, a voglibose/metformin FDC vs. the coadministration of the individual formulations, met the regulatory criteria for bioequivalence in healthy Korean subjects under fasting conditions. There was no significant difference in safety profiles between the two treatments.

Pharmacokinetic comparison of sustained- and immediate-release formulations of cilostazol after multiple oral doses in fed healthy male Korean volunteers

Background A new extended-release form of cilostazol has recently been developed. This study was conducted to compare the pharmacokinetic characteristics of sustained-release (SR) and immediate-release (IR) formulations of cilostazol after multiple oral doses in healthy male Korean volunteers. Methods This was an open-label, randomized, multiple-dose, crossover study conducted in 30 healthy Korean subjects. In each treatment period, subjects received oral doses of 200 mg SR formulation every 24 hours or 100 mg IR formulation every 12 hours for 5 consecutive days in a fed state, with a washout period of 9 days. The plasma concentrations of cilostazol and its metabolites were determined using a validated liquid chromatography-tandem mass spectrometry method. The area under the plasma concentration–time curve within a dosing interval (AUCT), the measured peak plasma concentration at steady state (Cmax,ss), and the time to reach Cmax,ss (tmax,ss) were analyzed using a noncompartmental method. Results A total of 24 healthy male subjects completed the study. The mean (standard deviation [SD]) AUCT (96–120 hours) values for SR and IR were 27,378.0 (10,301.6) ng·h/mL and 27,860.3 (7,152.3) ng·h/mL, respectively. The mean (SD) Cmax,ss values were 2,741.4 (836.0) ng/mL and 2,051.0 (433.2) ng/mL, respectively. The median tmax,ss values were 8.0 hours and 4.0 hours, respectively. The geometric mean ratios (90% confidence intervals) of the SR to IR formulations were 0.937 (0.863–1.017), 0.960 (0.883–1.043), and 0.935 (0.859–1.017) for AUCT and 0.644 (0.590–0.703), 0.586 (0.536–0.642), and 0.636 (0.577–0.702) for dose-normalized Cmax,ss of cilostazol, OPC-13015 (3,4-dehydro-cilostazol), and OPC-13213 (4′-trans-hydroxyl-cilostazol), respectively. All formulations were well tolerated. Conclusion At steady state, the AUCT of cilostazol SR 200 mg is comparable to that of cilostazol IR 100 mg twice a day in healthy male Korean subjects. Both formulations are well tolerated.

Assessment of the influence of severe renal impairment on the pharmacokinetics of mirodenafil in Korean male volunteers.

OBJECTIVE To evaluate and compare the pharmacokinetics and tolerability of a single oral dose of mirodenafil in volunteer patients with severe renal impairment and healthy volunteers. METHODS AND MATERIALS This open-label, single-dose, parallel group clinical study enrolled a total 12 volunteers (6 healthy volunteers and 6 volunteer patients with severe renal impairment). Each volunteer was orally administered 50 mg mirodenafil and serial blood samples were obtained after drug administration to determine the plasma concentration of mirodenafil using LC-MS/MS. The measured individual plasma concentrations were used to calculate the pharmacokinetic parameters using noncompartmental methods. Tolerability was also assessed using measurements of vital signs, clinical chemistry tests, and interviews. RESULTS All of the volunteers completed the study with no serious adverse events (AEs). A total of 4 AEs were reported, but all were of mild or moderate intensity and not considered to be related to the study drug. The geometric mean (95% CI) of the terminal half-life (t1/2β) and the apparent clearance (CL/F) values of mirodenafil were 2.2 (1.4 - 3.4) h and 127.2 (95.1 - 170.2) l/h in the volunteer patients, and 3.0 (2.1 - 4.4) h and 136.1 (74.4 - 249.2) l/h in the healthy volunteers, respectively. The geometric mean of the AUC0-t of the volunteer patients was 8% higher and the geometric mean for clearance was 7% lower compared with the healthy volunteers. However, the geometric mean of the Cmax of the volunteer patients was 38% higher than that of the healthy volunteers. CONCLUSIONS A single oral 50-mg dose of mirodenafil was well tolerated. Exposure (AUC0-t) to mirodenafil was similar in both healthy volunteers and volunteer patients with severe renal impairment and healthy volunteers.

Comparative pharmacokinetics of a fixed-dose combination vs concomitant administration of telmisartan and S-amlodipine in healthy adult volunteers

Objective This study compared the pharmacokinetic (PK) and safety profiles of a fixed-dose combination (FDC) formulation of telmisartan and S-amlodipine with those of concomitant administration of the two drugs. Materials and methods This was an open-label, randomized, crossover study in healthy male Koreans. All subjects were administered an FDC tablet containing 40 mg telmisartan and 5 mg S-amlodipine and were also coadministered the same dose of both drugs given separately. The crossover study design included a 14-day washout period between the two treatments. Blood samples were collected up to 168 h following drug administration. The plasma concentrations of telmisartan and S-amlodipine were determined by liquid chromatography tandem mass spectrometry. PK parameters and plasma concentration–time curves were compared. Safety was assessed by measuring vital signs, clinical laboratory tests, physical examinations, and patient interviews. Results The geometric mean ratios and 90% CIs for the maximum plasma concentration (Cmax) and area under the curve from time zero to the last sampling time (AUCt) were 0.8782 (0.8167–0.9444) and 0.9662 (0.9210–1.0136) for telmisartan and 1.0069 (0.9723–1.0427) and 1.0324 (0.9969–1.0690) for S-amlodipine, respectively. A total of 36 adverse events (AEs) were reported by 23 subjects, but no statistical differences were observed between the two treatments. The most frequently reported AE was a mild-to-moderate headache that was generally self-limiting. Conclusion For both telmisartan and S-amlodipine, the Cmax and AUCt 90% CIs were between ln (0.8) and ln (1.25). These results suggest that the FDC formulation is pharmacokinetically bioequivalent and has a similar safety profile to the coadministration of these drugs.