The effect of renal function on the pharmacokinetics and pharmacodynamics of enavogliflozin, a potent and selective sodium-glucose cotransporter-2 inhibitor, in type 2 diabetes

AIMS

To explore the effect of renal function on the pharmacokinetic (PK) and pharmacodynamic (PD) profile and safety of enavogliflozin, a selective sodium-glucose cotransporter 2 (SGLT2) inhibitor, in patients with type 2 diabetes mellitus (T2DM).

METHODS

An open-label, two-part clinical trial was conducted in T2DM patients, stratified by renal function: Group 1, normal renal function; Group 2, mild renal impairment (RI); Group 3, moderate RI; and Group 4, severe RI. In Part A, Groups 2 and 4 received enavogliflozin 0.5 mg once. In Part B, Groups 1 and 3 received enavogliflozin 0.5 mg once daily for 7 days. Serial blood and timed urine samples were collected to analyse the PK and PD characteristics of enavogliflozin. Pearson's correlation coefficients were calculated to assess the correlations between PK or PD parameters and creatinine clearance (CrCL).

RESULTS

A total of 21 patients completed the study as planned. The area under the curve (AUC) for enavogliflozin was not significantly correlated with CrCL, although the maximum concentration slightly decreased as renal function decreased. By contrast, daily urinary glucose excretion (UGE) was positively correlated with CrCL after both single- (r = 0.7866, p < 0.0001) and multiple-dose administration (r = 0.6606, p = 0.0438).

CONCLUSIONS

Systemic exposure to oral enavogliflozin 0.5 mg was similar among the patients with T2DM regardless of their renal function levels. However, the glucosuric effect of enavogliflozin decreased with RI. Considering the UGE observed and approved therapeutic use of other SGLT2 inhibitors, the efficacy of enavogliflozin with regard to glycaemic control could be explored in patients with mild and moderate RI (estimated glomerular filtration rate ≥30 or ≥45 mL/min/1.73 m2) in a subsequent larger study.

Adaptive design clinical trials: current status by disease and trial phase in various perspectives

An adaptive design is a clinical trial design that allows for modification of a structured plan in a clinical trial based on data accumulated during pre-planned interim analyses. This flexible approach to clinical trial design improves the success rate of clinical trials while reducing time, cost, and sample size compared to conventional methods. The purpose of this study is to identify the current status of adaptive design and present key considerations for planning an appropriate adaptive design based on specific circumstances. We searched for clinical trials conducted between January 2006 to July 2021 in the Clinical Trials Registry (ClinicalTrials.gov) using keywords specified in the Food and Drug Administration Adaptive Design Clinical Trial Guidelines. In order to analyze the adaptive designs used in selected cases, we classified the results according to the phase of the clinical trial, type of indication, and the specific adaptation method employed. A total of 267 clinical trials were identified on ClinicalTrials.gov. Among them, 236 clinical trials actually applied adaptive designs and were classified according to phase, indication types, and adaptation methods. Adaptive designs were most frequently used in phase 2 clinical trials and oncology research. The most commonly used adaptation method was the adaptive treatment selection design. In the case of coronavirus disease 2019, the most frequently used designs were adaptive platform design and seamless design. Through this study, we expect to provide valuable insights and considerations for the implementation of adaptive design clinical trials in different diseases and stages.

Pharmacokinetic Comparison Between a Fixed-Dose Combination of Empagliflozin L-Proline/Metformin and Empagliflozin/Metformin in Healthy Korean Subjects

Empagliflozin and metformin are oral antidiabetic drugs commonly used to treat type 2 diabetes mellitus as a combination therapy. This study aimed to compare the pharmacokinetics and safety of a newly developed fixed-dose combination of 5-mg empagliflozin L-proline and 1000-mg metformin with the reference drug. A randomized, open-label, single-dose, 2-period, 2-treatment, crossover study was conducted in healthy Korean subjects. The subjects received a single oral dose of reference drug or test drug at each period. The pharmacokinetic (PK) parameters were calculated using a noncompartmental method. The geometric mean ratios and 90% confidence intervals of the plasma maximum concentration (Cmax ) and area under the concentration-time curve from time zero to the last quantifiable concentration (AUClast ) were calculated. A total of 27 healthy subjects were included in the PK analysis. For empagliflozin, the geometric mean ratios (90% confidence intervals) of the test to reference drug for Cmax and AUClast were 1.03 (0.99-1.08) and 1.03 (1.00-1.06), respectively. For metformin, the corresponding values for Cmax  and AUClast were 0.99 (0.92-1.06) and 1.00 (0.94-1.06), respectively. In conclusion, a fixed-dose combination of empagliflozin L-proline and metformin showed similar PK characteristics to the reference drug, and both drugs were safe in healthy subjects.

The Effects of Glypican-3 Deficiency on Radiosensitivity in Liver Cancer Cells

PURPOSE/OBJECTIVE(S)

Glypican-3 (GPC-3), a heparan sulfate proteoglycan involved in cellular proliferation, modulates signaling of FGF/FGFR, IGF/IGFR, HGF/Met, Wnt/Frizzled, among others and correlates with survival. GPC-3 is overexpressed in the majority of hepatocellular carcinoma and hepatoblastoma, but not in normal hepatocytes. Accordingly, it is being investigated as a liver cancer-selective target for radiopharmaceutical imaging and therapy. However, the potential linkage between GPC-3 expression and radiosensitivity has not yet been defined. In this study, we investigated the effects of GPC-3 deficiency on radiosensitivity in liver cancer cell lines.

MATERIALS/METHODS

CRISPR/Cas9 system was used to engineer GPC-3 knockout variants of liver cancer cell lines, HepG2 & Hep3B, both of which natively express GPC-3. Confirmation of knockout of GPC-3 was evaluated by RT-PCR, western blotting, flow cytometry, immunocytochemistry, and gDNA sequencing. Cell growth and migration were evaluated by BrdU insertion and wound-healing assays, respectively. In vitro radiosensitivity was examined by radiation-induced apoptosis/necrosis (Annexin V-APC and PI staining), cell cycle modification, γH2AX foci formation, and clonogenic assays (6 Gy). Wildtype and knockout lines were engrafted into athymic mice to assess tumor growth kinetics.

RESULTS

RT-PCR, western blotting, flow cytometry, and immunocytochemistry all confirmed GPC-3 knockout in both HepG2 and Hep3B cell lines. Nucleotide deletion at exon 3 of the GPC-3 gene was confirmed by gDNA sequencing in HepG2ΔGPC3 and Hep3BΔGPC3. GPC-3 deficiency reduced liver cancer cell proliferation (HepG2ΔGPC3, p = 0.027, and Hep3BΔGPC3, p = 0.031) and migration (HepG2ΔGPC3: 1.5-fold, p<0.001, and Hep3BΔGPC3: 2.3-fold, p<0.001) significantly when compared with wild type. GPC-3 deficiency reduced cell survival and clonogenicity (HepG2ΔGPC3: DEF = 1.23, Hep3BΔGPC3: DEF = 1.23) in liver cancer cells exposed to irradiation (6 Gy). The delayed repair of double-stranded DNA damage was observed in irradiated GPC-3 deficient liver cancer cells. Tumor growth was dramatically delayed by GPC-3 deficiency. Tumor weight measured at 50 (Hep3B) and 60 (HepG2) days after liver cancer cell inoculation corroborated these effects.

CONCLUSION

Knockout lines of HepG2 and Hep3B exhibited decreased cell proliferation, migration, and in vivo tumor growth compared to wildtype. GPC-3 deficiency was associated with increased sensitivity to radiation therapy. Studies identifying the pathways through which this radiosensitivity is mediated are ongoing.

Identification of Hepatocellular Carcinoma-Specific Targets for Imaging and Therapy

PURPOSE/OBJECTIVE(S)

Despite advances in the diagnosis and treatment of hepatocellular carcinoma (HCC), there are no tumor-selective agents that are clinically approved in the US for this disease. Here, we aimed to identify and validate molecules that are overexpressed on HCC plasma membrane compared to normal tissues, which could be facilitate the design, engineering, and testing of tumor-selective imaging and therapeutic agents.

MATERIALS/METHODS

We analyzed next-generation sequencing (NGS) public datasets (TCGA and TIGER-LC) and NCI single cell RNA-sequencing datasets to identify overexpressed plasma membrane molecules and aimed to validate these targets using immunohistochemical staining (IHC) of patient tissue microarrays (TMAs), and flow cytometry using liver cancer cell lines (Huh7, HepG2, and Hep3B).

RESULTS

NGS data identified GPC3, EGFR, MET, MUC13, and ROBO1 molecules overexpressed in HCC relative to non-tumor tissues. In HepG2 cell line, EGFR (p<0.05) and MET (p<0.01) demonstrated statistically significant increased median fluorescence intensity (MFI) relative to controls in flow cytometry. In the Hep3B cell line, MET, GPC3, and EGFR demonstrated an increased MFI relative to the control (p<0.01). No statistically significant difference was observed in Huh7 cell lines. IHC staining of TMAs for GPC3, MET, MUC14, and ROBO1 showed statistically significantly higher staining relative to the normal tumor tissue (p<0.001).

CONCLUSION

We identified and validated plasma membrane molecules overexpressed in HCC compared to non-tumor tissue. Because GPC3, a well-known HCC-specific marker that is expressed in 75% of HCC, was identified using our approach, we are confident that that additional molecules may also represent promising HCC-selective targets. This work could facilitate the design, engineering, and testing of novel precision oncology imaging and therapeutic agents for HCC.

Quantification of OATP1B1 endogenous metabolites coproporphyrin I and III in human urine

Coproporphyrin (CP)-I and CP-III are the markers of organic anion-transporting polypeptides' (OATPs) activities, and they are porphyrin metabolites that originate from heme synthesis. Furthermore, CP-I and CP-III, which are OATP1B endogenous metabolites, have gradually attracted the attention of scientists and researchers in recent years. Previous studies have also observed CP-I and CP-III levels as clinical biomarkers for predicting OATP1B inhibition in drug-drug interaction studies. To establish an accurate ultra-high performance liquid chromatography-mass spectrometry method for the quantitation of CP-I and CP-III, we reviewed previous methodological publications and applied them to a clinical pharmacology study using a human urine matrix. We used 13.25 M formic acid as a working solution for internal standards (CP-I 15N4 and CP-III d8) to avoid isobaric interference. The calibration curve showed good linearity in the range of 1-100 ng/mL, with a correlation coefficient (R2) higher than 0.996 in each validation batch. Both the between-run and within-run assays achieved good precision and accuracy, and we found that both CP-I and CP-III were stable in the pre-study validation. The method exhibited suitable dilution integrity, allowing for the re-analysis of samples with concentrations exceeding the upper limit of quantification through dilution. Overall, the application of the described method in a clinical study revealed that it can be utilized effectively to monitor drug-drug interactions mediated by OATP1B.

Effect of Food on the Pharmacokinetics and Pharmacodynamics of a Novel Dual Delayed-Release Formulation of Esomeprazole in Healthy Subjects

A novel dual delayed-release formulation (DR) of esomeprazole was developed to prolong the effect of esomeprazole inhibiting gastric acid secretion. This study investigated the effect of food on the pharmacokinetics (PK) and pharmacodynamics (PD) of DR esomeprazole. A randomized, open-label, single-dose, 2-period, 2-sequence crossover study was conducted in healthy Korean subjects. Subjects were orally administered a single dose of 40- mg DR esomeprazole in fasted and fed states in each period. PK and PD characteristics evaluated through continuous 24-hour intragastric pH monitoring in fasted and fed states were compared between the 2 conditions. A total of 23 subjects completed the study and were included in the PK analysis. PD analysis was conducted in 21 subjects, excluding 2 subjects, because of inappropriate pH profiles. The systemic exposure of esomeprazole after a single dose of DR esomeprazole in the fed state decreased compared to that in the fasted state. However, the percentage decrease from baseline in integrated gastric acidity and the percentage of time at pH ≥4 were not significantly different between the 2 conditions. In conclusion, although the systemic exposure of esomeprazole decreased when DR esomeprazole was administered in the fed state compared to that in the fasted state, the degree of gastric acid secretion inhibition was not clinically different, regardless of food intake.

Population Pharmacokinetic-Pharmacodynamic Modeling of Carvedilol to Evaluate the Effect of Cytochrome P450 2D6 Genotype on the Heart Rate Reduction

BACKGROUND

Carvedilol is a beta-adrenergic receptor antagonist primarily metabolized by cytochromes P450 (CYP) 2D6. This study established a carvedilol population pharmacokinetic (PK)-pharmacodynamic (PD) model to describe the effects of CYP2D6 genetic polymorphisms on the inter-individual variability of PK and PD.

METHODS

The PK-PD model was developed from a clinical study conducted on 21 healthy subjects divided into three CYP2D6 phenotype groups, with six subjects in the extensive metabolizer (EM, *1/*1, *1/*2), seven in the intermediate metabolizer-1 (IM-1, *1/*10, *2/*10), and eight in the intermediate metabolizer-2 (IM-2, *10/*10) groups. The PK-PD model was sequentially developed, and the isoproterenol-induced heart rate changes were used to establish the PD model. A direct effect response and inhibitory E_max model were used to develop a carvedilol PK-PD model.

RESULTS

The carvedilol PK was well described by a two-compartment model with zero-order absorption, lag time, and first-order elimination. The carvedilol clearance in the CYP2D6*10/*10 group decreased by 32.8% compared with the other groups. The inhibitory concentration of carvedilol estimated from the final PK-PD model was 16.5 ng/mL regardless of the CYP2D6 phenotype.

CONCLUSION

The PK-PD model revealed that the CYP2D6 genetic polymorphisms were contributed to the inter-individual variability of carvedilol PK, but not PD.

Pharmacokinetics and safety of candidate tocilizumab biosimilar CT-P47 versus reference tocilizumab: a randomized, double-blind, single-dose phase I study

BACKGROUND

CT-P47 is a candidate tocilizumab biosimilar. This study assessed the pharmacokinetic (PK) equivalence of CT-P47 and European Union-approved reference tocilizumab (EU-tocilizumab) in healthy Asian adults.

RESEARCH DESIGN AND METHODS

This double-blind, multicenter, parallel-group trial randomized healthy adults (1:1) to receive a single (162 mg/0.9 mL) subcutaneous dose of CT-P47 or EU-tocilizumab. The primary endpoint (Part 2) was PK equivalence by area under the concentration - time curve (AUC) from time zero to last quantifiable concentration (AUC_0-last), AUC from time zero to infinity (AUC_0-inf), and maximum serum concentration (C_max). PK equivalence was concluded if 90% confidence intervals (CIs) for the ratios of geometric least-squares means (gLSMs) were within the 80-125% equivalence margin. Additional PK endpoints, immunogenicity, and safety were evaluated.

RESULTS

In Part 2, 289 participants were randomized (146 CT-P47; 143 EU-tocilizumab); 284 received study drug. AUC_0-last, AUC_0-inf, and C_max were equivalent between CT-P47 and EU-tocilizumab: 90% CIs for the ratios of gLSMs were within the 80-125% equivalence margin. Secondary PK endpoints, immunogenicity, and safety were comparable between groups.

CONCLUSIONS

CT-P47 demonstrated PK equivalence with EU-tocilizumab and was well tolerated, following a single dose in healthy adults.

CLINICAL TRIAL REGISTRATION

www.clinicaltrials.gov identifier is NCT05188378.

Evaluation of Vancomycin TDM Strategies: Prediction and Prevention of Kidney Injuries Based on Vancomycin TDM Results

The current guidelines for therapeutic drug monitoring (TDM) of vancomycin suggest a target 24-hour area under the curve (AUC_0-24) of 400 to 600 mg*h/L for serious methicillin-resistant Staphylococcus aureus infections. In this study, the predictabilities of acute kidney injury (AKI) of various TDM target parameters, target levels, and sampling methods were evaluated in patients who underwent TDM from January 2020 to December 2020. The AUC_0-24 and trough values were calculated by both one- and two-point sampling methods, and were evaluated for the predictability of AKI. Among the AUC_0-24 cutoff comparisons, the threshold value of 500 mg*h/L in the two sampling methods was statistically significant (P = 0.042) when evaluated for the predictability of AKI. Analysis by an receiver operating characteristic curve estimated an AUC_0-24 cutoff value of 563.45 mg*h/L as a predictor of AKI, and was proposed as the upper limit of TDM target.

Pharmacodynamic and Pharmacokinetic Drug Interactions between Fexuprazan, a Novel Potassium-Competitive Inhibitor, and Aspirin, in Healthy Subjects

Acid-reducing agents are commonly used for the prevention of aspirin-induced gastrointestinal complications such as peptic ulcers. As a novel potassium-competitive acid blocker, fexuprazan is expected to prevent aspirin-induced gastrointestinal complications. This randomized, open-label study aimed to evaluate the pharmacodynamic and pharmacokinetic interactions between aspirin and fexuprazan in healthy Koreans. Subjects randomized to the aspirin group received 500 mg aspirin in combination with 80 mg fexuprazan. For the fexuprazan group, fexuprazan 80 mg was administered alone and then in combination with aspirin 500 mg. Platelet aggregation inhibited by aspirin and the pharmacokinetic parameters of aspirin and fexuprazan were compared between monotherapy and combination therapy. A total of 22 subjects completed the study. The platelet aggregation-inhibitory activity and systemic exposure to aspirin were not significantly affected by fexuprazan coadministration. The systemic exposure of fexuprazan was decreased up to 20% by aspirin coadministration, which was not regarded as clinically meaningful considering the previously reported exposure-response relationship. In conclusion, there were no clinically relevant pharmacodynamic or pharmacokinetic interactions between aspirin and fexuprazan. This finding suggests the potential of fexuprazan for the prevention of aspirin-induced gastrointestinal complications, serving as a baseline for optimizing its therapeutic application with aspirin.

A Comparison of the Pharmacokinetics and Safety of Dapagliflozin Formate, an Ester Prodrug of Dapagliflozin, to Dapagliflozin Propanediol Monohydrate in Healthy Subjects

Background

Dapagliflozin formate (DAP-FOR, DA-2811), an ester prodrug of dapagliflozin, was developed to improve the stability and pharmaceutical manufacturing process of dapagliflozin, a sodium-glucose cotransporter-2 inhibitor.

Purpose

This study aimed to evaluate the pharmacokinetics (PKs) and safety of dapagliflozin for DAP-FOR compared to those for dapagliflozin propanediol monohydrate (DAP-PDH, Forxiga) in healthy subjects.

Methods

This was an open-label, randomized, single-dose, two-period, two-sequence crossover study. The subjects received a single dose of DAP-FOR or DAP-PDH 10 mg in each period, with a 7-day washout. Serial blood samples for PK analysis were collected up to 48 hours after a single administration to determine plasma concentrations of DAP-FOR and dapagliflozin. PK parameters were calculated using a non-compartmental method and compared between the two drugs.

Results

In total, 28 subjects completed the study. DAP-FOR plasma concentrations were not detected in all of the blood sampling time points except for one time point in one subject, and the corresponding DAP-FOR plasma concentration in the subject was close to the lower limit of quantification. The mean plasma concentration-time profiles of dapagliflozin were comparable between the two drugs. The geometric mean ratios and its 90% confidence intervals of the maximum plasma concentration and area under the plasma concentration-time curve of dapagliflozin for DAP-FOR to DAP-PDH were within the conventional bioequivalence range of 0.80-1.25. Both drugs were well-tolerated, with a similar incidence of adverse drug reactions.

Conclusion

The rapid conversion of DAP-FOR into dapagliflozin led to the extremely low exposure of DAP-FOR and comparable PK profiles of dapagliflozin between DAP-FOR and DAP-PDH. The safety profiles were also similar between the two drugs. These results suggest that DAP-FOR can be used as an alternative to DAP-PDH.

Population Pharmacokinetic Model of AST-001, L-Isomer of Serine, Combining Endogenous Production and Exogenous Administration in Healthy Subjects

AST-001 is an L-isomer of serine that has protective effects on neurological disorders. This study aimed to establish a population pharmacokinetic (PK) model of AST-001 in healthy Korean to further propose a fixed-dose regimen in pediatrics. The model was constructed using 648 plasma concentrations from 24 healthy subjects, including baseline endogenous levels during 24 h and concentrations after a single dose of 10, 20, and 30 g of AST-001. For the simulation, an empirical allometric power model was applied to the apparent clearance and volume of distribution with body weight. The PK characteristics of AST-001 after oral administration were well described by a two-compartment model with zero-order absorption and linear elimination. The endogenous production of AST-001 was well explained by continuous zero-order production at a rate of 0.287 g/h. The simulation results suggested that 2 g, 4 g, 7 g, 10 g, and 14 g twice-daily regimens for the respective groups of 10–14 kg, 15–24 kg, 25–37 kg, 38–51 kg, 52–60 kg were adequate to achieve sufficient exposure to AST-001. The current population PK model well described both observed endogenous production and exogenous administration of AST-001 in healthy subjects. Using the allometric scaling approach, we suggested an optimal fixed-dose regimen with five weight ranges in pediatrics for the upcoming phase 2 trial.

Safety, tolerability, and pharmacokinetics of single and multiple topical ophthalmic administration of imatinib mesylate in healthy subjects

For the long‐term efficacy of dry eye disease treatment, relieving underlying inflammation is necessary. Imatinib mesylate is a novel ophthalmic formulation of imatinib mesylate, which is expected to alleviate inflammation by inhibiting the discoidin domain receptor 1 activity. This study aims to evaluate the safety and pharmacokinetics of imatinib mesylate in healthy subjects. A randomized, double‐blind, placebo‐controlled study was conducted. In a single ascending dose, 16 subjects received a single eye drop of imatinib mesylate 0.1%, 0.3%, or matching placebo. In the multiple ascending dose (MAD), subjects received multiple eye drops of imatinib mesylate 0.1%, 0.3%, or matching placebo once daily for 7 days. Safety and tolerability were assessed by ophthalmic examination, including the visual analog scale (VAS) to monitor the burning sensation in the eyes. A total of four treatment‐emergent adverse events (TEAEs) occurred during the study. All TEAEs were mildly severe with no serious cases. VAS results in the 0.1% MAD group exhibited highest score of two points, whereas it was less than one point in others. Insignificant difference between the imatinib mesylate and placebo groups in the VAS results was seen. After a single dose administration of imatinib mesylate 0.1%, all plasma concentrations were below the lower limit of quantification. The peak plasma concentrations of imatinib were less than 0.54 µg/L in all groups. In conclusion, a single and multiple topical ophthalmic administration of imatinib mesylate was well‐tolerated in healthy subjects. Because there was minimal systemic exposure to imatinib, the adverse effect in the body seems to be insignificant.

A validated simple LC-MS/MS method for quantifying trimethylamine N-oxide (TMAO) using a surrogate matrix and its clinical application

Trimethylamine N-oxide (TMAO) is a small molecular amine oxide generated from dietary choline and carnitine through intestinal microbial metabolism. Recently, TMAO has attracted much public attention as its role in disease progression has been proven in many clinical studies. The plasma concentration of TMAO in humans was found to be positively associated with the increased risk of many diseases including cardiovascular diseases and chronic kidney diseases. To achieve accurate and sensitive quantitation of TMAO for clinical applications, we established and validated a simple quantitative method using a liquid chromatography tandem mass spectrometry (LC-MS/MS) system. We constructed an eight-point calibration curve in an artificial surrogate matrix instead of the commonly used biological matrices to avoid interference from the endogenous TMAO. The calibration curve showed excellent linearity in the range of 1 to 5,000 ng/mL, with a correlation coefficient (R²) higher than 0.996 in each validation batch. Moreover, both the intra-day and inter-day assays achieved satisfactory precision and accuracy results ranging from 1.65–7.15% and 96.36–111.43%, respectively. Further, this method was cross-validated using a human plasma matrix and applied to a clinical pharmacology study. Overall, these results demonstrate that the developed quantitation method is applicable in clinical research for monitoring disease progression and evaluating drug effects.

Effect of CYP3A4 metabolism on sex differences in the pharmacokinetics and pharmacodynamics of zolpidem

To investigate pharmacokinetic and pharmacodynamic differences of zolpidem between males and females and their causes, including CYP3A4 activity. A single oral dose of zolpidem (10 mg) was administered to 15 male and 15 female healthy subjects. Blood samples were collected up to 12 h post-dose to determine plasma zolpidem concentrations. Pharmacokinetic parameters were obtained using non-compartmental analysis. Digit symbol substitution test, choice reaction time, and visual analog scale of sleepiness were used to evaluate pharmacodynamics. We measured CYP3A4 activity using 4β-hydroxycholesterol, an endogenous metabolite. Mean maximum plasma concentration and area under the plasma concentration–time curve were higher for females than for males (9.9% and 32.5%, respectively); other pharmacokinetic parameters showed no significant differences. Pharmacodynamic scores for females showed delayed recovery compared with that for males. CYP3A4 activity was higher in females than in males (p = 0.030). There was no serious adverse event, and adverse event incidence was not different between the sexes. Zolpidem exposure was about 30% higher in females than in males. Delayed pharmacodynamic score recovery in females could be related to higher zolpidem concentrations. Although apparent clearance was lower in females, systemic clearance might not be the cause of the different exposures to zolpidem.

Safety, tolerability of ES16001, a novel varicella zoster virus reactivation inhibitor, in healthy adults

Purpose

Herpes zoster (HZ), or shingles, is a clinical syndrome resulting from the reactivation of latent varicella zoster virus (VZV) within the sensory ganglia. We evaluated the safety and tolerability of ES16001 (ethanol extract of Elaeocarpus sylvestris var. ellipticus), a novel inhibitor of varicella zoster virus reactivation in healthy adults.

Method

Single-center, randomized, double-blind, placebo-controlled, single and multiple ascending dose (SAD and MAD, respectively) studies were conducted in 20- to 45-year-old healthy adults without chronic disease. In the SAD study (n = 32), subjects randomly received a single oral dose of 240, 480, 960, or 1440 mg ES16001 or a placebo. In the MAD study (n = 16), subjects randomly received once daily doses of 480 or 960 mg ES16001 or a placebo for 5 days. The safety and tolerability of the drug were evaluated by monitoring participants’ treatment emergent adverse events (TEAEs) and vital signs, electrocardiograms (ECGs), physical examinations, and clinical laboratory tests.

Results

In the SAD study, 11 adverse reactions were seen in 5 subjects, and in the MAD study, 8 adverse reactions were seen in 6 subjects. All adverse reactions were mild, and no serious adverse reactions occurred. The most common adverse reaction was an increase in alanine aminotransferase (ALT), but all test values were in the clinically non-significant range, and their clinical significance was judged to be small considering the fact that most of the test values returned to normal immediately after the end of drug administration.

Conclusion

ES16001 has good safety and tolerability when administered both once and repeatedly to healthy subjects. Further research is needed to identify any possible drug-induced hepatotoxicity, which appears infrequently. Our findings provide a rationale for further clinical investigations of ES16001 for the prevention of HZ.

Trial registration: CRIS, KCT0006066. Registered 7 April 2021—Retrospectively registered, https://cris.nih.go.kr/cris/search/detailSearch.do/19071).

Supplementary Information

The online version contains supplementary material available at 10.1186/s40001-021-00565-z.

Influence of CYP2C19 Polymorphisms on the Pharmacokinetics of Omeprazole in Elderly Subjects

Omeprazole blocks the gastric H⁺ /K⁺  adenosine triphosphatase, thus inhibiting gastric acid secretion, and is metabolized by cytochrome P450 (CYP) 2C19. Due to the physiological changes in the elderly, there are different pharmacokinetic consequences compared to young people. The aim of this study was to evaluate the pharmacokinetic profiles of omeprazole in 15 elderly participants according to the CYP2C19 genotype. The concentration-time profiles of omeprazole and its metabolites, 5-hydroxy (5-OH) omeprazole and omeprazole sulfone, were similar between the CYP2C19 extensive metabolizer (EM) and intermediate metabolizer groups. In contrast, when comparing the EM group and CYP2C19 poor metabolizer (PM) group, the EM/PM geometric mean ratio (95% confidence interval) of area under the plasma concentration-time curve from time of dosing to the last measurable concentration was 0.52 (0.27-1.01) and that of the IM group was 0.71 (0.32-1.59), indicating that the exposure of omeprazole in the PM group was increased. The exposure of 5-OH omeprazole was significantly decreased in the PM group when compared to the EM group, with an EM/PM geometric mean ratio (95% confidence interval) of 2.20 (1.50-3.22). In conclusion, the tendency of drug exposure according to the CYP2C19 genotype in the elderly and young adults was similar in that the exposure level was highest in the PM group. However, when compared to young adults, the difference between the genotype groups was smaller in the elderly.

Changes in the gut microbiome influence the hypoglycemic effect of metformin through the altered metabolism of branched-chain and nonessential amino acids

AIMS

Although metformin has been reported to affect the gut microbiome, the mechanism has not been fully determined. We explained the potential underlying mechanisms of metformin through a multiomics approach.

METHODS

An open-label and single-arm clinical trial involving 20 healthy Korean was conducted. Serum glucose and insulin concentrations were measured, and stool samples were collected to analyze the microbiome. Untargeted metabolomic profiling of plasma, urine, and stool samples was performed by GC-TOF-MS. Network analysis was applied to infer the mechanism of the hypoglycemic effect of metformin.

RESULTS

The relative abundances of Escherichia, Romboutsia, Intestinibacter, and Clostridium were changed by metformin treatment. Additionally, the relative abundances of metabolites, including carbohydrates, amino acids, and fatty acids, were changed. These changes were correlated with energy metabolism, gluconeogenesis, and branched-chain amino acid metabolism, which are major metabolic pathways related to the hypoglycemic effect.

CONCLUSIONS

We observed that specific changes in metabolites may affect hypoglycemic effects through both pathways related to AMPK activation and microbial changes. Energy metabolism was mainly related to hypoglycemic effects. In particular, branched-chain amino acid metabolism and gluconeogenesis were related to microbial metabolites. Our results will help uncover the potential underlying mechanisms of metformin through AMPK and the microbiome.

Pharmacokinetics of a Fixed-Dose Combination of Amlodipine/Losartan and Chlorthalidone Compared to Concurrent Administration of the Separate Components

Hypertension is more effectively treated with coadministration of 2 or more antihypertensive drugs than with high-dose monotherapy. Therefore, calcium channel blockers, angiotensin II receptor blockers, and thiazides are coadministered to treat hypertension. The objective of this study was to compare the pharmacokinetic (PK) profiles of HCP1401, a fixed-dose combination of amlodipine 5 mg, losartan 100 mg, and chlorthalidone 25 mg, with the separate components (loose combination) of amlodipine/losartan 5/100 mg and chlorthalidone 25 mg. A randomized, open-label, single-dose, 2-way crossover study was conducted. Blood samples for amlodipine and chlorthalidone were collected for up to 144 hours after dosing, whereas those for losartan were collected up to 48 hours after dosing. The PK parameters of these drugs were calculated using a noncompartmental method. Sixty subjects completed the study. The geometric mean ratios and 90% confidence intervals of maximum plasma concentration and area under the concentration-time curve to the last measurable point for amlodipine, losartan, and chlorthalidone were within the conventional bioequivalence range of 0.80 to 1.25. There were no clinically significant changes in safety assessments, and the treatments were well tolerated. The PK characteristics and tolerability profiles of a single oral FDC of amlodipine, losartan, and chlorthalidone were equivalent to those of individual tablets in a loose combination.

Pharmacokinetics, Tolerability and Pharmacogenetics of DA-8031 After Multiple Ascending Doses in Healthy Male Subjects

Purpose

DA-8031 is a novel selective serotonin reuptake inhibitor for the treatment of premature ejaculation. This study investigated the pharmacokinetics, safety and tolerability of multiple oral doses of DA-8031. In addition, a genetic analysis was explored to evaluate the effect of genetic polymorphisms on the pharmacokinetics of DA-8031.

Subjects and Methods

A dose block-randomized, double-blind, placebo-controlled study was conducted in 3 dose groups with 20, 30 and 40 mg of DA-8031. Healthy male subjects were randomized to DA-8031 or placebo at a 4:1 ratio in each dose group of 10 subjects by oral administration once daily for 7 consecutive days. Serial blood and urine samples were collected for the pharmacokinetic evaluation, and the pharmacokinetic-related genes were analyzed by DMET^TM plus. A safety evaluation was conducted including adverse events (AEs) monitoring and 12-lead electrocardiogram (ECG).

Results

The plasma DA-8031 concentration reached the maximum concentration (C_max) in 2.2 to 3.0 h and was eliminated with a mean half-life of 25.5 to 26.7 h at steady state. The accumulation index of DA-8031 ranged 2.3 to 2.8. The systemic exposure of DA-8031 of the CYP2D6 intermediate metabolizer (IM) was significantly higher compared to the CYP2D6 poor metabolizer (PM). There were no clinically significant QTc interval changes, and all the adverse events were mild.

Conclusion

After multiple oral doses of DA-8031 20, 30, and 40 mg in this study, the systemic exposure of DA-8031 increased in a more than dose-proportional manner with the increasing doses, and DA-8031 was generally well tolerated. In addition, the genetic polymorphisms of CYP2D6 have an impact on the pharmacokinetics of DA-8031.

Assessment of Oral Vancomycin-Induced Alterations in Gut Bacterial Microbiota and Metabolome of Healthy Men

Several classes of antibiotics have reduced the mortality caused by infectious diseases; however, orally administered antibiotics alter the composition of gut microbiota, leading to dysbiosis-related disease. Therefore, in this study, we used 16S rRNA gene sequencing- and metabolomics-based approaches to investigate the effects of oral vancomycin on gut bacterial microbiota and the metabolome in biospecimens collected from healthy men. Samples collected from 11 healthy men were analyzed using 16S rRNA gene sequencing and metabolomics. 16S rRNA gene sequencing was performed to analyze the gut bacterial microbiota, and GC-TOFMS-based untargeted metabolomics was performed to analyze fecal, urine, and plasma metabolomics. Spearman's rank correlation was utilized to explore the associations between gut bacterial microbiota and metabolome. Fecal 16S rRNA gene sequencing analysis showed decreased relative abundance of genera belonging to the phyla Bacteroidetes and Firmicutes, and increased relative abundance of genera of the phyla Proteobacteria and Fusobacteria. Fecal metabolomics analysis showed that levels of uracil, L-aspartic acid, lithocholic acid, and deoxycholic acid were significantly higher at baseline, whereas that of dihydrouracil was significantly higher after vancomycin administration. No significant metabolic markers were selected from urine and plasma metabolomics analysis. This study demonstrates that oral vancomycin administration induces alterations in gut bacterial microbiota and metabolome. Correlation analysis between our two datasets shows that alteration of the gut bacterial microbiota, induced by oral vancomycin, potentially affected the systemic activity of dihydropyrimidine dehydrogenase. This correlation should be further examined in future studies to define the effects of gut bacterial microbiota on drug-metabolizing enzymes, thereby contributing to the development of personalized therapy.

Effects of vancomycin-induced gut microbiome alteration on the pharmacodynamics of metformin in healthy male subjects

Metformin is a major treatment for type 2 diabetes. This study was conducted to investigate the impact of gut microbiome dysbiosis on the pharmacokinetics and antihyperglycemic effects of metformin. Healthy adult males aged 19-45 years with no defecation abnormalities were recruited for this 4-period clinical study: baseline; post-metformin (i.e., multiple oral doses of 1000 mg metformin on days 1-4); post-vancomycin (i.e., multiple oral doses of 500 mg vancomycin on days 11-17 inducing gut microbiome changes); and post-metformin + vancomycin (i.e., multiple oral doses of 1000 mg metformin on days 16-19). In each period, serum glucose and insulin concentrations following an oral glucose tolerance test, fecal samples for gut microbiome composition, and safety data were obtained. Following metformin dosing, plasma and urine samples for pharmacokinetics were collected. Nine subjects completed the study. The pharmacokinetics of metformin remained unchanged, and the antihyperglycemic effect was significantly decreased after vancomycin administration (p value = 0.039), demonstrating the weak relationship between the pharmacokinetics and pharmacodynamics of metformin. Relative abundances of some genus were changed after vancomycin administration, and tended to correlate with the antihyperglycemic effects of metformin (p value = 0.062 for Erysipelatoclostridium; p value = 0.039 for Enterobacter; and p value = 0.086 for Faecalibacterium). Adverse events occurred in all subjects and were resolved without sequelae. In conclusion, a decrease in the antihyperglycemic effect of metformin was observed after concomitant administration with vancomycin, without changes in metformin pharmacokinetics. The antihyperglycemic effect was tended to correlate with the relative abundance of several genus, suggesting that the effect of metformin is partly attributable to the gut microbiome (ClinicalTrials.gov, NCT03809260).

Current Bioequivalence Study Designs in South Korea: A Comprehensive Analysis of Bioequivalence Study Reports Between 2013 and 2019

Demonstration of bioequivalence (BE) is mandatory while developing generic drugs. The scientific concept of BE applies equally to different regulatory agencies. However, the application of the concept may differ for each agency, which can affect the design of BE studies. To evaluate the study practices in terms of the BE concept in South Korea, we retrospectively analyzed BE study reports available from Ministry of Food and Drug Safety between 2013 and 2019. Statistical estimation of the pharmacokinetic parameters, including peak concentration and area under the concentration-time curve to the last measurable concentration, as well as study design, number of subjects in a study, study duration, fasting status, and formulation of specific drugs were obtained. The drugs were classified per World Health Organization Anatomical Therapeutic Chemical Classification and Biopharmaceutics Classification System. Post-hoc intrasubject coefficient of variation and corresponding sample sizes were calculated from the 90% confidence intervals of pharmacokinetic parameters. A total of 143 generic drugs in 588 BE studies were analyzed. The largest number of studies were performed in the area of Cardiovascular system (172 studies), followed by Nervous system (143 studies) and Alimentary tract and metabolism (92 studies). Overall, BE studies in South Korea were conducted in accordance with the global guideline despite the differences in details. BE studies were focused on the several therapeutic areas and conducted in a similar manner. The number of subjects was generally larger than that estimated with 90% power.

Population Pharmacokinetic Modelling and Simulation to Determine the Optimal Dose of Nanoparticulated Sorafenib to the Reference Sorafenib

Sorafenib, an oral multikinase inhibitor, exhibits a highly variable absorption profile due to enterohepatic reabsorption and poor solubility. SYO-1644 improved the solubility of sorafenib by nanoparticulation technology leading to enhanced bioavailability. To evaluate the pharmacokinetically equivalent dose of SYO-1644 to the reference Nexavar^® 200 mg, a randomized, open-label, replicated two-period study was conducted in healthy volunteers. A total of 32 subjects orally received a single dose of the following assigned treatment under a fasted state in the first period and repeated once more in the second period with a two-week washout: SYO-1644 100, 150 and 200 mg and Nexavar^® 200 mg. Pharmacokinetic (PK) samples were collected up to 168 h post-dose. The PK profile was evaluated by both non-compartmental analysis and population PK method. With the final model, 2 × 2 crossover trial scenarios with Nexavar^® 200 mg and each dose of SYO-1644 ranging from 100 to 150 mg were repeated 500 times by Monte Carlo simulation, and the proportion of bioequivalence achievement was assessed. Transit absorption compartments, followed by a one-compartment model with first-order elimination and enterohepatic reabsorption components were selected as the final model. The simulation results demonstrated that the SYO-1644 dose between 120 and 125 mg could yielded the highest proportion of bioequivalence.

Population pharmacokinetic/pharmacodynamic modeling of delayed effect of escitalopram-induced QT prolongation

BACKGROUND

A thorough QT study identified that escitalopram-induced QT prolongation was delayed. This study thus aimed to develop a population pharmacokinetic (PK)/pharmacodynamic (PD) model to characterize the relationship between escitalopram concentrations and the delayed effect on QT prolongation.

METHODS

The data of completed subjects who had placebo (n=36) and a single dose of 20 mg escitalopram (n=33) from a previous thorough QT study were used. Population PK/PD analysis was performed by nonlinear mixed-effects modeling. A escitalopram concentration-drug effect model was developed with estimated individual PK and baseline QT parameters. To explain the relationship between escitalopram concentrations and QT prolongation delay, an effect compartment model was utilized.

RESULTS

A two-compartment model with first-order absorption and lag time and first-order elimination adequately described the PK of escitalopram. The circadian rhythm of baseline QT interval was best explained by two harmonic cosine functions. A linear model properly characterized escitalopram-induced QT prolongation. The average estimated maximal QT prolongation was 5.4 ms (range: 1.9-7.6 ms). The equilibrium half-life of delayed QT prolongation was 1.9 h. The drug effect of QTc change compared with that at baseline remained relatively constant from 1.3 to 3.5 ms over 24 h, and the maximum QTc change occurred with a 3-h delay after the time to the maximum plasma concentration.

LIMITATIONS

We did not include genetic polymorphisms, such as CYP2C19, as potential covariates owing to limited information.

CONCLUSIONS

These results may provide useful information on when to monitor electrocardiogram in patients who require intensive care after drug administration.

Relationship among genetic polymorphism of SLCO1B1, rifampicin exposure and clinical outcomes in patients with active pulmonary tuberculosis

AIMS

Rifampicin is a key drug for the treatment of tuberculosis (TB). Little is known for the relationship between the rifampicin pharmacokinetics and genetic polymorphisms in the Asian population. We aimed to investigate relationship between genetic polymorphism of SLCO1B1 and rifampicin exposure and its impact on clinical outcomes in Korean patients with active pulmonary TB.

METHODS

From February 2016 to December 2019, patients with active pulmonary TB who were taking rifampicin for >1 week were prospectively enrolled. Serial or 1-time blood sampling was conducted to determine rifampicin concentrations. The genotype of 4 single nucleotide polymorphisms of SLCO1B1 was determined. To estimate the drug clearance and exposure, population pharmacokinetics analysis was conducted. Clinical outcomes such as time to acid-fast bacteria culture conversion, chest radiograph score changes from baseline, and all-cause mortality were also evaluated. The exposure among different SLCO1B1 genotype was compared and relationship between drug exposure and clinical outcomes were explored.

RESULTS

A total of 105 patients (70 males and 35 females) were included in the final analysis. The mean age of patients was 55.4 years. The mean drug clearance and exposure were 13.6 L/h and 57.9 mg h/L, respectively. The genetic polymorphisms of SLCO1B1 were not related to rifampicin clearance or exposure. As the rifampicin exposure increased, the chest radiographs improved significantly, but the duration of acid-fast bacteria culture conversion was not related to the drug exposure.

CONCLUSION

SLCO1B1 gene polymorphisms did not influence rifampicin concentrations and clinical outcomes in Korean patients with active pulmonary TB.

Impact of a computerised clinical decision support system on vancomycin loading and the risk of nephrotoxicity

BACKGROUND

A vancomycin loading dose is recommended for the treatment of serious methicillin-resistant Staphylococcus aureus (MRSA) infections. However, clinicians often do not adhere to these recommendations, mainly due to nephrotoxicity risk, unfamiliarity with the guideline, or complexity of calculating an individual dose. Therefore, we introduced a computerised clinical decision support system (CDSS) for vancomycin loading (hereafter Vancomycin CDSS) to promote the use of vancomycin loading dose.

METHODS

We describe a quasi-experimental study spanning 6 months before and 18 months after the deployment of a Vancomycin CDSS. The Vancomycin CDSS was integrated into the hospital's electronic medical record system in the form of a vancomycin order set. Our primary endpoint was the incidence of nephrotoxicity; the secondary endpoint was mean initial vancomycin trough levels. We also conducted a survey to evaluate the reasons why clinicians opted not to utilise a vancomycin loading dose.

RESULTS

After implementation of Vancomycin CDSS, 363 out of 746 patients (49 %) who were first administered vancomycin received a loading dose. We did not find significant differences in nephrotoxicity between the pre- and post-intervention groups, nor between the loading- and non-loading groups. In the pre-intervention group, the mean initial vancomycin trough level was 7.10 mg/L, which was significantly lower than that in the post-intervention group of 11.11 mg/L. In the vancomycin loading group, the mean initial trough level was 11.95 mg/L, compared to 7.55 mg/L in the non-loading group. The main reason stated for not prescribing a vancomycin loading dose was concern about nephrotoxicity.

CONCLUSION

Introduction of the Vancomycin CDSS did not increase nephrotoxicity and increased the mean initial dose and trough level of vancomycin.

Development and validation of a method for the simultaneous quantification of endogenous steroids metabolized by CYP3A

Cytochrome P450 (CYP) 3A enzymes, the most important phase 1 drug-metabolizing enzymes, are responsible for 50% of the metabolism of clinically used drugs. CYP3A activity varies widely among individuals, which can affect the probability of adverse drug reactions and drug-drug interactions mediated by the induction or inhibition of the enzyme. Hence, it is important to be able to predict CYP3A activity in individuals to reduce the incidence of unexpected drug responses. To specifically and quickly measure CYP3A activity, we developed method based on gas chromatography interfaced with triple-quadrupole mass spectrometry for the quantification of cortisol, cortisone, 6β-hydroxycortisol, and 6β-hydroxycortisone simultaneously in urine and 4β-hydroxycholesterol in plasma. The results were calculated based on charcoal-stripped steroid-free urine and plasma control samples. The accuracy and precision were 93.18% to 110.0% and 1.96% to 5.34%, respectively. This method was then applied to measure endogenous steroids from urine and plasma samples of healthy Korean males and females. The calibration curves of all analytes showed good linearity with a correlation coefficient (r²) that ranged from 0.9953 to 0.9999. Therefore, this validated method can be used to measure endogenous biomarkers to predict CYP3A activity and might be applicable in the prediction of CYP3A-mediated drug interactions of new drug candidates.

Pharmacokinetics and Pharmacodynamics of Ursodeoxycholic Acid in an Overweight Population With Abnormal Liver Function

Ursodeoxycholic acid (UDCA) is a secondary bile acid that is used to treat primary biliary cholangitis. Although UDCA has a hepatoprotective effect in some diseases, its benefit in nonalcoholic fatty liver disease (NAFLD) remains controversial. We aimed to evaluate the pharmacokinetics (PK) and pharmacodynamics (PD) of UDCA in overweight subjects with elevated liver enzymes after multiple administrations of UDCA and compare these changes with vitamin E treatment. Overweight subjects (body mass index, 25-30 kg/m² ) with elevated alanine aminotransferase (ALT) level (40-200 IU/L) were enrolled. Subjects received one of the following three 8-week treatments: UDCA 300 mg twice daily UDCA 300 mg twice daily for 4 weeks followed by UDCA 300 mg twice daily and metformin 500 mg twice daily for 4 weeks, and vitamin E 400 IU twice daily. PK and PD (liver function, lipid profiles, insulin sensitivity, and miR-122) analyses were performed. Thirty subjects were enrolled; 1 subject withdrew his consent during the study. The PK characteristics were similar to those of healthy volunteers. The ALT and miR-122 levels decreased in the UDCA groups, whereas the ALT and aspartate aminotransferase levels decreased in the vitamin E group. The lipid profiles and insulin sensitivity did not show significant changes among the groups. There was no serious adverse event, and the safety profiles were similar among the treatment groups. The liver enzyme and miR-122 levels were decreased by UDCA. Considering UDCA and vitamin E have a hepatoprotective effect and different mechanisms of action, combination therapy could be an option for NAFLD.

Comparison of Pharmacokinetics of a Fixed-Dose Combination of Amlodipine/Losartan/Rosuvastatin with Concomitant Administration of Amlodipine/Losartan and Rosuvastatin in Healthy Volunteers

Background

A fixed-dose combination (FDC) tablet formulation of amlodipine/losartan/rosuvastatin 5/100/20 mg was developed to improve medication compliance in patients with both hypertension and dyslipidemia. The comparative pharmacokinetic study was performed to compare the profile of an FDC tablet formulation of amlodipine/losartan/rosuvastatin with that of concomitant administration of a currently marketed FDC tablet of amlodipine/losartan with a rosuvastatin tablet.

Subjects and Methods

A randomized, open-label, single oral dose, two-way crossover study was conducted in 60 healthy subjects. Subjects were orally administered the FDC tablet of amlodipine/losartan/rosuvastatin and a loose combination (LC) of two tablets comprising an FDC of amlodipine/losartan and rosuvastatin. Blood samples were collected for up to 144 h post dose for pharmacokinetic evaluations. Plasma concentrations of amlodipine, losartan, EXP3174 (an active metabolite of losartan), and rosuvastatin were measured by using liquid chromatography-tandem mass spectrometry. The geometric mean ratio (GMR) and its 90% confidence interval (90% CI) in the FDC treatment to LC treatment for the area under the concentration-time curve from zero to the last quantifiable time point (AUC_last) and the maximum plasma concentration (C_max) were calculated. Safety was monitored throughout the study.

Results

The GMR (90% CI) values of AUC_last and C_max were 0.9946 (0.9663–1.0238) and 0.9690 (0.9379–1.0011) for amlodipine, 0.9855 (0.9422–1.0308) and 0.9178 (0.8349–1.0089) for losartan, 0.9814 (0.9501–1.0136) and 0.9756 (0.9313–1.0219) for EXP3174, and 0.9448 (0.8995–0.9923) and 0.9609 (0.8799–1.0494) for rosuvastatin, respectively. No clinically significant changes were observed in any of the safety parameters, including clinical laboratory tests, vital signs, electrocardiograms, and physical examinations, between the FDC treatment and the LC treatment.

Conclusion

We confirmed the pharmacokinetic equivalence of the FDC and LC treatments. This triple combination FDC formulation could be a clinically useful replacement for LC therapy.

Development of a physiologically-based pharmacokinetic model for cyclosporine in Asian children with renal impairment

This study aimed to assess the pharmacokinetics of cyclosporine A (CsA) in Asian children with renal impairment (RI) by developing a physiologically-based pharmacokinetic (PBPK) model with Simcyp Simulator. The PBPK model of Asian children with RI was developed by modifying the physiological parameters of the built-in population libraries in Simcyp Simulator. The ratio of healthy and RI populations was obtained for each parameter showing a difference between the populations. Each ratio was multiplied by the corresponding parameter in healthy Asian children. The model verification was performed with published data of Korean children with kidney disease given multiple CsA administrations. Simulations were performed with different combinations of ethnicity, age, and renal function to identify the net impact of each factor. The simulated results suggested that the effect of RI was higher in children than adults for both Caucasian and Asian. In conclusion, the constructed model adequately characterized CsA pharmacokinetics in Korean children with RI. Simulations with populations categorized by ethnicity, age, and renal function enabled to assess the net impact of each factor on specific populations.

Development of a Korean-specific virtual population for physiologically based pharmacokinetic modelling and simulation

Physiologically based pharmacokinetic (PBPK) modelling and simulation is a useful tool in predicting the PK profiles of a drug, assessing the effects of covariates such as demographics, ethnicity, genetic polymorphisms and disease status on the PK, and evaluating the potential of drug-drug interactions. We developed a Korean-specific virtual population for the SimCYP® Simulator (version 15 used) and evaluated the population's predictive performance using six substrate drugs (midazolam, S-warfarin, metoprolol, omeprazole, lorazepam and rosuvastatin) of five major drug metabolizing enzymes (DMEs) and two transporters. Forty-three parameters including the proportion of phenotypes in DMEs and transporters were incorporated into the Korean-specific virtual population. The simulated concentration-time profiles in Koreans were overlapped with most of the observed concentrations for the selected substrate drugs with a < 2-fold difference in clearance. Furthermore, we found some drug models within the SimCYP® library can be improved, e.g., the minor allele frequency of ABCG2 and the fraction metabolized by UGT2B15 should be incorporated for rosuvastatin and lorazepam, respectively. The Korean-specific population can be used to evaluate the impact of ethnicity on the PKs of a drug, particularly in various stages of drug development.

Digital therapeutics and clinical pharmacology

Digital therapeutics (DTx) is a new subsection of digital health that is primarily driven by software and will be of great interest to clinical pharmacologists. In this article, an overview of DTx, including definition, position in the landscape of therapeutics, product categories, benefits, and challenges, is provided. Discussions from the point of view of clinical pharmacology are presented, as DTx should have exposure-response relationships. The principles of clinical pharmacology can be applied to DTx as they are comparable to pharmacotherapy. Clinical pharmacology has great potential in the development, application, and regulation of DTx.

Ursodeoxycholic acid improves liver function via phenylalanine/tyrosine pathway and microbiome remodelling in patients with liver dysfunction

Ursodeoxycholic acid (UDCA) is a metabolic by-product of intestinal bacteria, showing hepatoprotective effects. However, its underlying molecular mechanisms remain unclear. The purpose of this study was to elucidate the action mechanisms underlying the protective effects of UDCA and vitamin E against liver dysfunction using metabolomics and metagenomic analysis. In this study, we analysed blood and urine samples from patients with obesity and liver dysfunction. Nine patients were randomly assigned to receive UDCA (300 mg twice daily), and 10 subjects received vitamin E (400 IU twice daily) for 8 weeks. UDCA significantly improved the liver function scores after 4 weeks of treatment and effectively reduced hepatic deoxycholic acid and serum microRNA-122 levels. To better understand its protective mechanism, a global metabolomics study was conducted, and we found that UDCA regulated uremic toxins (hippuric acid, p-cresol sulphate, and indole-derived metabolites), antioxidants (ascorbate sulphate and N-acetyl-L-cysteine), and the phenylalanine/tyrosine pathway. Furthermore, microbiome involvement, particularly of Lactobacillus and Bifidobacterium, was demonstrated through metagenomic analysis of bacteria-derived extracellular vesicles. Meanwhile, vitamin E treatment did not result in such alterations, except that it reduced uremic toxins and liver dysfunction. Our findings suggested that both treatments were effective in improving liver function, albeit via different mechanisms.

Safety, tolerability and pharmacokinetics of 21 day multiple oral administration of a new oxazolidinone antibiotic, LCB01-0371, in healthy male subjects

Background

LCB01-0371 is a new oxazolidinone antibiotic, which targets most Gram-positive organisms. High rates of adverse reactions including myelosuppression have been reported for existing oxazolidinones, limiting their long-term use.

Objectives

The safety, tolerability and pharmacokinetics (PK) of 21 day multiple oral administrations of LCB01-0371 in healthy male subjects (clinicaltrials.gov: NCT02540460) were investigated.

Methods

In this randomized, double-blind, placebo-controlled study, subjects received 800 mg of LCB01-0371 once or twice daily or 1200 mg of LCB01-0371 twice-daily for 21 days in a fasting state. Safety and tolerability profiles including laboratory tests were evaluated during the study and on a post-study visit and the results were analysed using repeated-measures analysis of variance (RM-ANOVA). Serial blood samples for PK analysis were collected up to 12 h after dosing on day 21.

Results

A total of 40 subjects were enrolled and 34 subjects completed the study. Two subjects dropped out according to stopping rules. In the 1200 mg twice-daily dose group, the absolute value of red blood cell count, haematocrit and haemoglobin decreased by 500 × 106/L (6.5%), 4.5% (6.8%) and 1.6 g/dL (6.9%), respectively, after 21 day administrations of LCB01-0371. However, mean relative changes from baseline of all haematology values were not significantly different among doses, including placebo (all, P < 0.05). PK profiles of LCB01-0371 in the dose range of 800 mg once daily to 1200 mg twice daily were consistent with previous studies.

Conclusions

LCB01-0371 is well tolerated in healthy male subjects with comparable haematology profiles to placebo, after multiple doses of up to 1200 mg twice daily for 21 days.

Physiologically Based Pharmacokinetic Modelling and Prediction of Metformin Pharmacokinetics in Renal/Hepatic-Impaired Young Adults and Elderly Populations

BACKGROUND AND OBJECTIVES

Physiologically based pharmacokinetic (PBPK) modelling and simulation enable researchers to overcome practical limitations for clinical trials on special populations. This study was conducted to investigate how the PBPK model describes the pharmacokinetics of metformin in young adult and elderly populations and to predict the pharmacokinetics of metformin in patients with renal or hepatic impairment in both populations.

METHODS

A first-order absorption/PBPK model for metformin was built in the Simcyp simulator version 14 release 1. A full PBPK model was constructed for metformin based on physicochemical properties and clinical observations. The model was refined and validated using clinical plasma concentration data obtained in healthy young adults and elderly after the oral administration of metformin. Metformin pharmacokinetics in patients with renal or hepatic impairment were then investigated and compared by simulation.

RESULTS

The PBPK model reasonably predicted the pharmacokinetic profiles of metformin for both young adults and the elderly. The predicted pharmacokinetic parameters, including maximum concentration, area under the time-concentration curve, and apparent oral clearance values, were within 1.5-fold of the observed data of metformin. In the simulation results, the systemic exposure of metformin was expected to be markedly increased not only with a decrease in renal function but also with severe hepatic impairments.

CONCLUSIONS

The PBPK model adequately characterised the pharmacokinetics of metformin in both young adult and elderly populations. PBPK modelling and simulation can be used as a useful tool to investigate and compare the pharmacokinetics in geriatric populations incorporating various disease conditions.

Effect of plasma membrane monoamine transporter genetic variants on pharmacokinetics of metformin in humans

Metformin, an oral hypoglycemic agent belonging to biguanide class, is widely used to treat type 2 diabetes mellitus, and several drug transporters such as organic cation transporters (OCTs), multidrug and toxin extrusion transporter (MATE), and plasma membrane monoamine transporter (PMAT) are thought to affect its disposition. We evaluated the role of PMAT genetic variations on the pharmacokinetic characteristics of metformin in a Korean population. In this retrospective study, 91 healthy subjects from four different metformin pharmacokinetic studies were analyzed; in each study, the subjects were administered two oral doses of metformin at intervals of 12 hours and dose-normalized pharmacokinetic parameters were compared between the subjects' genotypes. Subjects who had more than one allele of c.883-144A>G single nucleotide polymorphism (SNP) in PMAT gene (rs3889348) showed increased renal clearance of metformin compared to wild-type subjects (814.79 ± 391.73 vs. 619.90 ± 195.43 mL/min, p=0.003), whereas no differences in metformin exposure were observed between the PMAT variant subjects and wild-type subjects. Similarly, subjects with variant rs316019 SNP in OCT2 showed decreased renal clearance of metformin compared to wild-type subjects (586.01 ± 160.54 vs. 699.13 ± 291.40 mL/min, p=0.048). Other SNPs in PMAT and MATE1/2-K genes did not significantly affect metformin pharmacokinetics. In conclusion, the genetic variation of c.883-144A>G SNP in PMAT significantly affects the renal clearance of metformin in healthy Korean male subjects.

Effect of food on the pharmacokinetic characteristics of a single oral dose of LCB01-0371, a novel oxazolidinone antibiotic

Background

LCB01-0371 is a novel oxazolidinone antibiotic that blocks protein production by binding to bacterial 23S ribosomes. This antibiotic is active against Gram-positive bacteria. This study aimed to evaluate the effect of food on the pharmacokinetics (PKs) of LCB01-0371 and evaluate its safety profile.

Subjects and methods

A randomized, open-label, two-way crossover study was performed in 18 healthy Korean male subjects. All subjects received a single oral 800 mg dose of LCB01-0371 in each period under fed or fasting condition with a 7-day washout in between. The fed condition was defined as consumption of a meal of 800–1,000 kcal containinĝ50% of fat content. Serial blood samples were collected over 24 h after dosing, and the PK parameters were calculated by noncompartment analysis. All available data of the subjects who received LCB01-0371 at least once were included in the safety data summaries.

Results

In the fed condition, both the maximum plasma concentration (C_max) and the total systemic exposure (area under the plasma concentration–time curve from time zero to the last observed time point [AUC_last]) decreased by ~33% and 10%, respectively. The time to reach C_max was delayed by ~1.25 h in the fed condition, whereas the mean elimination half-life remained similar in both conditions. In the fed/fasting condition, the geometric mean ratios and 90% CI of the C_max and AUC_last were 0.666 (0.470–0.945) and 0.897 (0.761–1.057), respectively. There were no drug-related adverse events (AEs) or serious AEs.

Conclusion

Although the T_max after a single oral 800 mg dose of LCB01-0371 was slightly delayed under the fed condition compared to the fasting condition, the total systemic exposure was similar under both conditions. Therefore, LCB01-0371 could be administered regardless of food intake.

Retraction and Republication: A post hoc analysis of intra-subject coefficients of variation in pharmacokinetic measures to calculate optimal sample sizes for bioequivalence studies

[This retracts the article on p. 179 in vol. 25.].

A post hoc analysis of intra-subject coefficients of variation in pharmacokinetic measures to calculate optimal sample sizes for bioequivalence studies

Because bioequivalence studies are performed using a crossover design, information on the intra-subject coefficient of variation (intra-CV) for pharmacokinetic measures is needed when determining the sample size. However, calculated intra-CVs based on bioequivalence results of identical generic drugs produce different estimates. In this study, we collected bioequivalence results using public resources from the Ministry of Food and Drug Safety (MFDS) and calculated the intra-CVs of various generics. For the generics with multiple bioequivalence results, pooled intra-CVs were calculated. The estimated intra-CVs of 142 bioequivalence studies were 14.7±8.2% for AUC and 21.7±8.8% for Cmax. Intra-CVs of Cmax were larger than those of area under the concentration-time curve (AUC) in 129 studies (90.8%). For the 26 generics with multiple bioequivalence results, the coefficients of variation of intra-CVs between identical generics (mean±sd (min ~ max)) were 38.0±24.4% (1.9 ~ 105.3%) for AUC and 27.9±18.2% (4.0 ~ 70.1%) for Cmax. These results suggest that substantial variation exists among the bioequivalence results of identical generics. In this study, we presented the intra-CVs of various generics with their pooled intra-CVs. The estimated intra-CVs calculated in this study will provide useful information for planning future bioequivalence studies. (This is republication of the article 'Transl Clin Pharmacol 2017;25:179-182' retracted from critical typographic errors. See the 'Retraction and Republication section of this issue for further information).

A non-linear pharmacokinetic-pharmacodynamic relationship of metformin in healthy volunteers: An open-label, parallel group, randomized clinical study

Background

The aim of this study was to explore the pharmacokinetic-pharmacodynamic (PK-PD) relationship of metformin on glucose levels after the administration of 250 mg and 1000 mg of metformin in healthy volunteers.

Methods

A total of 20 healthy male volunteers were randomized to receive two doses of either a low dose (375 mg followed by 250 mg) or a high dose (1000 mg followed by 1000 mg) of metformin at 12-h intervals. The pharmacodynamics of metformin was assessed using oral glucose tolerance tests before and after metformin administration. The PK parameters after the second dose were evaluated through noncompartmental analyses. Four single nucleotide polymorphisms in MATE1, MATE2-K, and OCT2 were genotyped, and their effects on PK characteristics were additionally evaluated.

Results

The plasma exposure of metformin increased as the metformin dose increased. The mean values for the area under the concentration-time curve from dosing to 12 hours post-dose (AUC_0-12h) were 3160.4 and 8808.2 h·μg/L for the low- and high-dose groups, respectively. Non-linear relationships were found between the glucose-lowering effect and PK parameters with a significant inverse trend at high metformin exposure. The PK parameters were comparable among subjects with the genetic polymorphisms.

Conclusions

This study showed a non-linear PK-PD relationship on plasma glucose levels after the administration of metformin. The inverse relationship between systemic exposure and the glucose-lowering effect at a high exposure indicates a possible role for the intestines as an action site for metformin.

Trial registration

ClinicalTrials.gov NCT02712619

A post hoc analysis of intra-subject coefficients of variation in pharmacokinetic measures to calculate optimal sample sizes for bioequivalence studies

Because bioequivalence studies are performed using a crossover design, information on the intra-subject coefficient of variation (intra-CV) for pharmacokinetic measures is needed when determining the sample size. However, calculated intra-CVs based on bioequivalence results of identical generic drugs produce different estimates. In this study, we collected bioequivalence results using public resources from the Ministry of Food and Drug Safety (MFDS) and calculated the intra-CVs of various generics. For the generics with multiple bioequivalence results, pooled intra-CVs were calculated. The estimated intra-CVs of 142 bioequivalence studies were 14.7±8.2% for AUC and 21.7±8.8% for Cmax. Intra-CVs of Cmax were larger than those of area under the concentration-time curve (AUC) in 129 studies (90.8%). For the 26 generics with multiple bioequivalence results, the coefficients of variation of intra-CVs between identical generics (mean±sd (min ~ max)) were 38.0±24.4% (1.9 ~ 105.3%) for AUC and 27.9±18.2 % (4.0 ~ 70.1%) for Cmax. These results suggest that substantial variation exists among the bioequivalence results of identical generics. In this study, we presented the intra-CVs of various generics with their pooled intra-CVs. The estimated intra-CVs calculated in this study will provide useful information for planning future bioequivalence studies.

Role of the Fc Region in the Vitreous Half-Life of Anti-VEGF Drugs

Purpose

To identify the role of the fragment crystallizable (Fc) region in determining intraocular protein drug pharmacokinetics.

Methods

We generated a new VEGF-Trap lacking the Fc region (FcfVEGF-Trap, MWt = 100 kDa) by replacing the Fc region of native VEGF-Trap (MWt = 145 kDa) with a dimerized coiled-coil domain. Forty-two rabbits were injected intravitreally with VEGF-Trap or FcfVEGF-Trap (n = 21 each) in one of the eyes, harvested at six time points (1 hour and 1, 2, 4, 14, and 30 days after injections). VEGF-Trap and FcfVEGF-Trap concentrations in the vitreous, aqueous humor, and retina/choroid were measured, and drug pharmacokinetic properties were analyzed.

Results

In all three ocular compartments, the maximal concentrations for both FcfVEGF-Trap and VEGF-Trap were observed at 1 hour after injection. Half-lives of FcfVEGF-Trap in the vitreous and retina/choroid (145.02 and 102.12 hours, respectively) were 1.39 and 2.30 times longer than those of VEGF-Trap (103.99 and 44.42 hours, respectively). Total exposure of the aqueous humor and retina/choroid to FcfVEGF-Trap was 13.2% and 39% of the vitreous exposure, respectively, whereas VEGF-Trap concentrations were 25.2% and 26.2%, indicating that FcfVEGF-Trap shows a preference for posterior distribution and elimination.

Conclusions

FcfVEGF-Trap, despite its lower molecular weight, showed longer half-lives in vitreous and retina/choroid than VEGF-Trap did, suggesting that Fc receptors in ocular tissues contribute to anti-VEGF drug elimination. Truncation or mutation of the Fc region can prolong the intraocular residence time of VEGF-Trap and possibly reduce the number of VEGF-Trap injections required in clinical practice.

Safety, Tolerability, and Pharmacokinetic Characteristics of a Novel Nonopioid Analgesic, VVZ-149 Injections in Healthy Volunteers: A First-in-Class, First-in-Human Study

VVZ-149, a dual antagonist of GlyT2 and 5HT₂ A receptors, is an investigational analgesic with a novel mechanism of action that is currently under early-stage clinical development as an injectable agent for the treatment of postoperative pain. Here, the safety, tolerability, and pharmacokinetics of VVZ-149 injections in healthy male volunteers were explored in a randomized, double-blind, single- and multiple-ascending-dose (SAD and MAD, respectively), placebo-controlled clinical study. Subjects randomly received a 4-hour intravenous infusion of 0.25-8 mg/kg VVZ-149 or placebo in the SAD study (n = 46) or a 4-hour intravenous infusion of 4-7 mg/kg VVZ-149 or placebo twice daily for 3 days in the MAD study (n = 20). Serial blood and urine samples were collected for the pharmacokinetic analysis of VVZ-149 and its active metabolite (VVZ-368). Noncompartmental and compartmental pharmacokinetic analyses were performed. Various dosing scenarios were simulated to identify the adequate dosing regimen for the subsequent trials. Plasma exposure to VVZ-149 and VVZ-368 showed a dose-proportional increase. VVZ-149 did not accumulate in the plasma, whereas the plasma concentration of VVZ-368 increased by 1.23- to 2.49-fold after the fifth and sixth doses, respectively, in the MAD trial. Among the simulated dosing regimens, a loading dose followed by a maintenance dose was found to be an optimal dosing regimen, yielding the effective concentration estimated from animal studies in rat models of neuropathic or inflammatory pain. Single- or multiple-dose administration of VVZ-149 was generally well tolerated. These results showed that 0.5-8 mg/kg VVZ-149 exhibited linear pharmacokinetic characteristics and can be safely administered in further clinical studies.

Single-stage cell-based cartilage repair in a rabbit model: cell tracking and in vivo chondrogenesis of human umbilical cord blood-derived mesenchymal stem cells and hyaluronic acid hydrogel composite

OBJECTIVE

Human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) have gained popularity as a promising cell source for regenerative medicine, but limited in vivo studies have reported cartilage repair. In addition, the roles of MSCs in cartilage repair are not well-understood. The purpose of this study was to investigate the feasibility of transplanting hUCB-MSCs and hyaluronic acid (HA) hydrogel composite to repair articular cartilage defects in a rabbit model and determine whether the transplanted cells persisted or disappeared from the defect site.

DESIGN

Osteochondral defects were created in the trochlear grooves of the knees. The hUCB-MSCs and HA composite was transplanted into the defect of experimental knees. Control knees were transplanted by HA or left untreated. Animals were sacrificed at 8 and 16 weeks post-transplantation and additionally at 2 and 4 weeks to evaluate the fate of transplanted cells. The repair tissues were evaluated by gross, histological and immunohistochemical analysis.

RESULTS

Transplanting hUCB-MSCs and HA composite resulted in overall superior cartilage repair tissue with better quality than HA alone or no treatment. Cellular architecture and collagen arrangement at 16 weeks were similar to those of surrounding normal articular cartilage tissue. Histological scores also revealed that cartilage repair in experimental knees was better than that in control knees. Immunohistochemical analysis with anti-human nuclear antibody confirmed that the transplanted MSCs disappeared gradually over time.

CONCLUSION

Transplanting hUCB-MSCs and HA composite promote cartilage repair and interactions between hUCB-MSCs and host cells initiated by paracrine action may play an important role in cartilage repair.

S-1-Induced Lacrimal Drainage Obstruction and Its Association with Ingredients/Metabolites of S-1 in Tears and Plasma: A Prospective Multi-institutional Study

Purpose

This prospective study was conducted to determine the incidence of lacrimal drainage obstruction (LDO) during S-1 chemotherapy and evaluate the association between the development of LDO and the concentrations of ingredients/metabolites of S-1 in tears and plasma.

Materials and Methods

A total of 145 patients with gastric cancer who received adjuvant S-1 therapy were enrolled. Ophthalmologic examinations were performed regularly during S-1 chemotherapy. Concentrations of tegafur, 5-chloro-2,4-dihydroxypyridine (CDHP), and 5-fluorouracil at steady-state trough level were measured in both tears and plasma.

Results

Fifty-three patients (37%) developed LDO. The median time to the onset of LDO was 10.9 weeks, and LDO developed most frequently in the nasolacrimal duct. Univariable analyses revealed that an older age (≥ 70 years), creatinine clearance rate (Ccr) < 80 mL/min, 5-fluorouracil concentration in plasma ≥ 22.3 ng/mL (median), CDHP concentration in plasma ≥ 42.0 ng/mL (median), and tegafur concentration in tears ≥ 479.2 ng/mL (median) were related to increased development of LDO. Multivariable analysis indicated that a high plasma 5-fluorouracil concentration was predictive of increased development of LDO (hazard ratio, 2.02; p=0.040), along with older age and decreased Ccr. Patients with LDO also developed S-1–related non-hematologic toxicity more frequently than those without LDO (p=0.016).

Conclusion

LDO is a frequent adverse event during S-1 chemotherapy. An older age, decreased Ccr, and high plasma 5-fluorouracil concentration were found to be independent risk factors for LDO. The high incidence of LDO warrants regular ophthalmologic examination and early intervention in patients receiving S-1 therapy.