Time-course cross-species transcriptomics reveals conserved hepatotoxicity pathways induced by repeated administration of cyclosporine A.

Cyclosporine A (CsA) has shown efficacy against immunity-related diseases despite its toxicity in various organs, including the liver, emphasizing the need to elucidate its underlying hepatotoxicity mechanism. This study aimed to capture the alterations in genome-wide expression over time and the subsequent perturbations of corresponding pathways across species. Six data from humans, mice, and rats, including animal liver tissue, human liver microtissues, and two liver cell lines exposed to CsA toxic dose, were used. The microtissue exposed to CsA for 10 d was analyzed to obtain dynamically differentially expressed genes (DEGs). Single-time points data at 1, 3, 5, 7, and 28 d of different species were used to provide additional evidence. Using liver microtissue-based longitudinal design, DEGs that were consistently up- or down-regulated over time were captured, and the well-known mechanism involved in CsA toxicity was elucidated. Thirty DEGs that consistently changed in longitudinal data were also altered in 28-d rat in-house data with concordant expression. Some genes (e.g. TUBB2A, PLIN2, APOB) showed good concordance with identified DEGs in 1-d and 7-d mouse data. Pathway analysis revealed up-regulations of protein processing, asparagine N-linked glycosylation, and cargo concentration in the endoplasmic reticulum. Furthermore, the down-regulations of pathways related to biological oxidations and metabolite and lipid metabolism were elucidated. These pathways were also enriched in single-time-point data and conserved across species, implying their biological significance and generalizability. Overall, the human organoids-based longitudinal design coupled with cross-species validation provides temporal molecular change tracking, aiding mechanistic elucidation and biologically relevant biomarker discovery.

Genotype-based enrichment study design for minimizing the sample size in bioequivalence studies using tolterodine and CYP2D6 genotype
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OBJECTIVE: The objective of this study was to explore a pharmacogenomic information-based enrichment study design for reducing the sample size in bioequivalence (BE) studies using tolterodine and CYP2D6 genotypes. MATERIALS AND METHODS: A BE study of tolterodine was performed in a randomized, open-label, 2×2 cross-over design. A two one-sided test (TOST) was executed for pharmacokinetic (PK) parameters of tolterodine, and their geometric mean ratios (GMRs) with 90% confidence intervals (CIs) were estimated. The coefficient of variation (CV) was calculated for each cytochrome P450 (CYP) 2D6 genotype group, and the sample size required to meet the power of an equivalence test was estimated, based on TOST in genotype stratified groups as well as in a conventional group. Replicated simulation datasets of PK parameters for each genotype group were generated using bootstrap resampling technique. RESULTS: The CVs of PK parameters in the conventional dataset were much greater than those in the genotype-based stratified groups. While up to 70 subjects were required for statistical power based on the CV of the area under the concentration-time curve (AUCt) observed in the conventional dataset, only 26 - 44 subjects in extensive metabolizers (EMs) and poor metabolizers (PMs), respectively, were required for the CYP2D6 genotype groups. The 90% CIs for GMR in all simulated datasets appeared to meet the BE criterion (0.8 - 1.25). CONCLUSION: This exploration demonstrated that a drug-metabolizing enzyme genotype-based enrichment strategy can be implemented to minimize the sample size in BE studies of drugs that have high PK variability due to polymorphic metabolizing enzyme(s).

Genome-wide and candidate gene approaches of clopidogrel efficacy using pharmacodynamic and clinical end points-Rationale and design of the International Clopidogrel Pharmacogenomics Consortium (ICPC).

RATIONALE: The P2Y12 receptor inhibitor clopidogrel is widely used in patients with acute coronary syndrome, percutaneous coronary intervention, or ischemic stroke. Platelet inhibition by clopidogrel shows wide interpatient variability, and high on-treatment platelet reactivity is a risk factor for atherothrombotic events, particularly in high-risk populations. CYP2C19 polymorphism plays an important role in this variability, but heritability estimates suggest that additional genetic variants remain unidentified. The aim of the International Clopidogrel Pharmacogenomics Consortium (ICPC) is to identify genetic determinants of clopidogrel pharmacodynamics and clinical response. STUDY DESIGN: Based on the data published on www.clinicaltrials.gov, clopidogrel intervention studies containing genetic and platelet function data were identified for participation. Lead investigators were invited to share DNA samples, platelet function test results, patient characteristics, and cardiovascular outcomes to perform candidate gene and genome-wide studies. RESULTS: In total, 17 study sites from 13 countries participate in the ICPC, contributing individual patient data from 8,829 patients. Available adenosine diphosphate-stimulated platelet function tests included vasodilator-stimulated phosphoprotein assay, light transmittance aggregometry, and the VerifyNow P2Y12 assay. A proof-of-principle analysis based on genotype data provided by each group showed a strong and consistent association between CYP2C19*2 and platelet reactivity (P value=5.1 × 10-40). CONCLUSION: The ICPC aims to identify new loci influencing clopidogrel efficacy by using state-of-the-art genetic approaches in a large cohort of clopidogrel-treated patients to better understand the genetic basis of on-treatment response variability.

Pharmacodynamic effects of voglibose administered alone, administered with metformin, and administered with metformin in a fixed-dose combination in healthy Korean subjects
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OBJECTIVE: This study aimed at exploring the effects of metformin on the pharmacodynamics of voglibose, while investigating the pharmacodynamics between a fixed-dose combination (FDC) of voglibose/metformin and coadministered doses of voglibose and metformin tablets in healthy Korean subjects. MATERIALS AND METHODS: A randomized, open-label, 2×3×3 crossover study with a 9-day washout period was conducted in 30 healthy subjects. All subjects received orally administered voglibose alone, individual voglibose and metformin tablets, or FDC 3 times daily for 5 days. Oral sucrose was administered on day -1 (pretreatment) and at 10 minutes after the morning dose of the study drug on day 5 of each period. Plasma glucose and serum insulin were measured over the course of 2 hours following sucrose loading. RESULTS: 21 subjects completed the study. The geometric mean ratios (GMR) of ΔCmax and the AUC of glucose for voglibose plus metformin vs. voglibose alone were 0.995 (90% CI, 0.800 - 1.237) and 0.969 (90% CI, 0.949 - 0.990), respectively; the GMRs for individual tablets vs. FDC were 1.118 (90% CI, 0.930 - 1.344) and 1.010 (90% CI, 0.974 - 1.048), respectively. A relatively smaller number of subjects experienced adverse events when receiving voglibose alone compared to those administered FDC or metformin and voglibose. There were no significant differences in adverse events between individual voglibose and metformin tablets and FDC. CONCLUSION: Coadministered metformin did not have statistically or clinically significant effects on the pharmacodynamics of voglibose in healthy subjects. Glucose levels following sucrose loading seem not to be clinically different between FDC and individual tablets of voglibose and metformin.
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Evaluation of the incremental prognostic value of the combination of CYP2C19 poor metabolizer status and ABCB1 3435 TT polymorphism over conventional risk factors for cardiovascular events after drug-eluting stent implantation in East Asians.

PURPOSE: We evaluated the incremental prognostic value of combining the CYP2C19 poor metabolizer (PM) and ABCB1 3435 TT for adverse clinical outcomes over conventional risk factors in a percutaneous coronary intervention (PCI) cohort. METHODS: We enrolled 2,188 patients. The primary end point was a composite of death from any cause, nonfatal myocardial infarction (MI), and stroke during 1-year follow-up. The population was stratified into the following four groups: CYP2C19 EM/IM+ABCB1 3435 CC/CT, CYP2C19 EM/IM+ABCB1 3435 TT, CYP2C19 PM+ABCB1 3435 CC/CT, and CYP2C19 PM+ABCB1 3435 TT. RESULTS: A total of 87 (3.97%) primary end-point events occurred (64 deaths, 8 non-fatal MIs and 15 strokes). Multivariate Cox analysis indicated that CYP2C19 PM+ABCB1 3435 TT status was a significant predictor of the primary end point (hazard ratio = 4.51, 95% confidence interval (CI) = 1.92-10.58). However, addition of combined genetic status to the clinical risk model did not improve the model discrimination (C-statistic = 0.786 (95% CI = 0.734-0.837) to 0.785 (95% CI = 0.733-0.838)) or risk reclassification (categorical net reclassification improvement (0.040, P = 0.32), integrated discrimination improvement (0.021, P = 0.026)). CONCLUSIONS: In a real-world East Asian PCI population taking clopidogrel, although the concurrent presence of CYP2C19 PM and ABCB1 TT is a strong independent predictor of adverse outcomes, the combined status of two at-risk variants does not have an incremental prognostic value beyond that of the conventional clinical risk factors.Genet Med 18 8, 833-841.

The pharmacokinetic and pharmacodynamic interaction of clopidogrel and cilostazol in relation to CYP2C19 and CYP3A5 genotypes.

AIM: The primary objective of the present study was to evaluate the pharmacokinetic and pharmacodynamic interactions between clopidogrel and cilostazol in relation to the CYP2C19 and CYP3A5 genotypes. METHODS: In a randomized, three-way crossover study, 27 healthy subjects were administered clopidogrel (300 mg), cilostazol (100 mg) or clopidogrel + cilostazol orally. Plasma concentrations of clopidogrel, cilostazol and their active metabolites (clopidogrel thiol metabolite, 3,4-dehydrocilostazol and 4″-trans-hydroxycilostazol), and adenosine diphosphate-induced platelet aggregation were measured for pharmacokinetic and pharmacodynamic assessment. RESULTS: The area under the plasma concentration-time curve (AUC) of the active thiol metabolite of clopidogrel was highest in the CYP2C19 extensive metabolizers (EM) and lowest in the poor metabolizers (PM). Cilostazol decreased the thiol metabolite AUC by 29% in the CYP3A5*1/*3 genotype [geometric mean ratio (GMR) 0.71; 90% confidence interval (CI) 0.58, 0.86; P = 0.020] but not in the CYP3A5*3/*3 genotype (GMR 0.93; 90% CI 0.80, 1.10; P = 0.446). Known effects of the CYP2C19 and CYP3A5 genotypes on the exposure of cilostazol and its metabolites were observed but there was no significant difference in the AUC of cilostazol and 3,4-dehydrocilostazol between cilostazol and clopidogrel + cilostazol. The inhibition of platelet aggregation from 4 h to 24 h (IPA4-24 ) following the administration of clopidogrel alone was highest in the CYP2C19 EM genotype and lowest in the CYP2C19 PM genotype (59.05 ± 18.95 vs. 36.74 ± 13.26, P = 0.023). However, the IPA of the CYP2C19 PM following co-administration of clopidogrel and cilostazol was comparable with that of the CYP2C19 EM and intermediate metabolizers (IM) only in CYP3A5*3/*3 subjects. CONCLUSIONS: The additive antiplatelet effect of cilostazol plus clopidogrel is maximized in subjects with both the CYP2C19 PM and CYP3A5*3/*3 genotypes because of a lack of change of clopidogrel thiol metabolite exposure in CYP3A5*3/*3 as well as the highest cilostazol IPA in CYP2C19 PM and CYP3A5*3/*3 subjects.

A phase I study of UGT1A1 *28/*6 genotype-directed dosing of irinotecan (CPT-11) in Korean patients with metastatic colorectal cancer receiving FOLFIRI.

PURPOSE: A UGT1A1 genotype-directed dose escalation of irinotecan (CPT-11) was performed in patients with metastatic colorectal cancer receiving first-line FOLFIRI chemotherapy. METHODS: Patients were genotyped for UGT1A1 and stratified according to the number of defective alleles (DA; *28 and *6). The irinotecan dose was escalated with a fixed dose of 5-fluorouracil and leucovorin in a standard 3 + 3 design. RESULTS: In 43 enrolled patients, the maximum tolerated dose (MTD) was 300 mg/m² for the 1 DA group, while the MTD was not reached for the 0 DA group with 1 dose-limiting toxicity (DLT) at 330 mg/m² and for the 2 DA group with 0 DLT at 150 mg/m². Because of the risk of being exposed to unsafe doses, the trial was terminated before the MTD was reached in the 0 DA and 2 DA groups. The recommended doses were 300 (0 DA), 270 (1 DA) and 150 (0 DA) mg/m². The 2 DA group displayed 27% lower SN-38 exposure levels relative to the 0 and 1 DA groups (95% CI, 0.47-1.15). CONCLUSIONS: The MTD of irinotecan differed according to the UGT1A1 genotype, and higher doses of irinotecan are feasible with sLV5FU2 compared to the present regulatory approved doses.

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 coadministered 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 noncompartmental 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 amlodipine adipate/valsartan fixed-dose combination with amlodipine besylate/valsartan fixed-dose combination in healthy volunteers.

The aim of this study was to compare pharmacokinetic characteristics of fixed-dose combination (FDC) of two different salt form of amlodipine, amlodipine adipate/valsartan and amlodipine besylate/ valsartan, in healthy Korean volunteers under fasting conditions. A randomized, open-label, single-dose, two-treatment, two-way crossover study with a 14-day wash-out period was conducted. Plasma samples were collected for up to 144 hours for amlodipine and 24 hours for valsartan. Plasma concentrations of amlodipine and valsartan were analyzed using a validated ultra-performance liquid chromatography tandem mass-spectrometry. A non-compartmental method was used to calculate pharmacokinetic parameters. Vital signs and adverse events were monitored and physical examinations, laboratory tests, and electrocardiograms were conducted to evaluate safety. 44 subjects completed the study. The 90% CIs for the geometric mean ratio of Cmax and the AUC0-t were 93.5 - 100.4% and 93.2 - 98.3% for amlodipine, and 92.1 - 121.3% and 94.1 - 115.2% for valsartan, respectively. 17 adverse events occurred in 15 subjects during the study; 5 and 7 adverse drug reactions from the 5 and 6 subjects were considered to probably be related to the test and reference treatments respectively. All adverse drug reactions were in line with those known for the reference drug. All subjects recovered fully with no sequelae. A FDC of amlodipine adipate/valsartan and amlodipine besylate/valsartan combination tablets met the regulatory criteria for bioequivalence. In addition, no significant difference was observed in the safety assessments between two treatments. Thus, the newly developed FDC of amlodipine adipate/valsartan seems to be interchangeable with amlodipine besylate valsartan combination.

The effect of Ginkgo biloba extracts on the pharmacokinetics and pharmacodynamics of cilostazol and its active metabolites in healthy Korean subjects.

AIMS: The primary objective of this study was to evaluate the effects of Ginkgo biloba extracts (GBE) on the pharmacokinetics of cilostazol and its metabolites. The secondary objective was to assess the effect of GBE on the pharmacodynamics of cilostazol. METHODS: A randomized, double-blind, two-way crossover study was conducted with 34 healthy Korean subjects. All subjects were given an oral dose of cilostazol (100 mg) plus GBE (80 mg) or cilostazol (100 mg) plus placebo twice daily for 7 days. Plasma concentrations of cilostazol and its active metabolites (3,4-dehydrocilostazol and 4'-trans-hydroxycilostazol) were measured using liquid chromatography-tandem mass spectroscopy on day 7 for pharmacokinetic assessment. The adenosine diphosphate-induced platelet aggregation and bleeding time were measured at baseline and on day 7 for pharmacodynamic assessment. RESULTS: The geometric mean ratios of area under the concentration-time curve for dosing interval for cilostazol plus GBE vs. cilostazol plus placebo were 0.96 (90% confidence interval, 0.89-1.03; P = 0.20) for cilostazol, 0.96 (90% confidence interval, 0.90-1.02; P = 0.30) for 3,4-dehydrocilostazol and 0.98 (90% confidence interval, 0.93-1.03; P = 0.47) for 4'-trans-hydroxycilostazol. The change of aggregation after administration of cilostazol plus GBE seemed to be 1.31 times higher compared with cilostazol plus placebo, without statistical significance (P = 0.20). There were no significant changes in bleeding times and adverse drug reactions between the treatments. CONCLUSIONS: Co-administration of GBE showed no statistically significant effects on the pharmacokinetics of cilostazol in healthy subjects. A large cohort study with long-term follow-up may be needed to evaluate the possible pharmacodynamic interaction between cilostazol and GBE, given that there was a remarkable, but not statistically significant, increase in inhibition of platelet aggregation.

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.

Development of a multiplex and cost-effective genotype test toward more personalized medicine for the antiplatelet drug clopidogrel.

There has been a wide range of inter-individual variations in platelet responses to clopidogrel. The variations in response to clopidogrel can be driven by genetic polymorphisms involved in the pathway of absorption, distribution, metabolism, excretion, and the target receptor P2Y12. A set of genetic variants known for causing variations in clopidogrel responses was selected, which included CYP2C19*2, *3, *17, CYP2B6*4, *6, *9, CYP3A4*18, CYP3A5*3, MDR1 2677G>T/A, 3435C>T, and P2Y12 H2 (742T>C). The simultaneous detection of these 10 variants was developed by using a multiplex PCR and single-base extension (MSSE) methodology. The newly developed genotyping test was confirmed by direct DNA sequencing in the representative positive control samples and validated in an extended set of 100 healthy Korean subjects. Genotyping results from the developed MSSE exhibited a perfect concordance with the direct DNA sequencing data and all of variants tested in 100 healthy Korean subjects were in agreement with Hardy-Weinberg equilibrium (p>0.05). The present molecular diagnostic studies provide an accurate, convenient, and fast genotyping method for the detection of multiple variants. This would be helpful for researchers, as well as clinicians, to use genetic information toward more personalized medicine of clopidogrel and other antiplatelet drugs in the future.

Emerging and upcoming therapies in insomnia.

Insomnia, commonly treated with benzodiazepine (BZD) receptor agonists, presents challenges due to associated serious side effects such as abuse and dependence. To address these concerns, many researches have been conducted to develop and advance both pharmacological and non-pharmacological interventions. Dual orexin receptor antagonists (DORAs), which include suvorexant, daridorexant and lemborexant, have recently been approved by United States Food and Drug Administration (US FDA) as a novel pharmacotherapeutic alternative. Unlike BZD receptor agonists that act as positive allosteric modulators of the gamma-aminobutyric acid type A subunit alpha 1 receptor, DORAs function by binding to both orexin receptor types 1 and 2, and inhibiting the action of the wake-promoting orexin neuropeptide. These drugs induce normal sleep without sleep stage change, do not impair attention and memory performance, and facilitate easier awakening. However, more real-world safety information is needed. Selective orexin-2 receptor antagonists (2-SORAs) is under clinical developments. This review provides an overview of the mechanism of action in relation to insomnia, pharmacokinetics, efficacy and safety information of DORAs and SORA. According to insomnia management guidelines, the first-line treatment for chronic insomnia is cognitive behavioral therapy for insomnia (CBT-I). Although it has proven effective in improving sleep-related quality of life, it has several restrictions limitations due to a face-to-face format. Recently, prescription digital therapy such as Somryst® was approved by US FDA. Somryst®, a smartphone app-based CBT-I, demonstrated meaningful responses in patients. However, digital limitations may impact scalability. Overall, these developments offer promising alternatives for insomnia treatment, emphasizing safety, efficacy, and accessibility.

Cyclosporine A-induced systemic metabolic perturbations in rats: A comprehensive metabolome analysis.

A better understanding of cyclosporine A (CsA)-induced nephro- and hepatotoxicity at the molecular level is necessary for safe and effective use. Utilizing a sophisticated study design, this study explored metabolic alterations after long-term CsA treatment in vivo. Rats were exposed to CsA with 4, 10, and 25 mg/kg for 4 weeks and then sacrificed to obtain liver, kidney, urine, and serum for untargeted metabolomics analysis. Differential network analysis was conducted to explore the biological relevance of metabolites significantly altered by toxicity-induced disturbance. Dose-dependent toxicity was observed in all biospecimens. The toxic effects were characterized by alterations of metabolites related to energy metabolism and cellular membrane composition, which could lead to the cholestasis-induced accumulation of bile acids in the tissues. The unfavorable impacts were also demonstrated in the serum and urine. Intriguingly, phenylacetylglycine was increased in the kidney, urine, and serum treated with high doses versus controls. Differential correlation network analysis revealed the strong correlations of deoxycytidine and guanosine with other metabolites in the network, which highlighted the influence of repeated CsA exposure on DNA synthesis. Overall, prolonged CsA administration had system-level dose-dependent effects on the metabolome in treated rats, suggesting the need for careful usage and dose adjustment.

Metabolic phenotyping and global functional analysis facilitate metabolic signature discovery for tuberculosis treatment monitoring.

Tracking alterations in polar metabolite and lipid levels during anti-tuberculosis (TB) interventions is an emerging biomarker discovery and validation approach due to its sensitivity in capturing changes and reflecting on the host status. Here, we employed deep plasma metabolic phenotyping to explore the TB patient metabolome during three phases of treatment: at baseline, during intensive phase treatment, and upon treatment completion. Differential metabolites (DMs) in each period were determined, and the pathway-level biological alterations were explored by untargeted metabolomics-guided functional interpretations that bypassed identification. We identified 41 DMs and 39 pathways that changed during intensive phase completion. Notably, levels of certain amino acids including histidine, bile acids, and metabolites of purine metabolism were dramatically increased. The altered pathways included those involved in the metabolism of amino acids, glycerophospholipids, and purine. At the end of treatment, 44 DMs were discovered. The levels of glutamine, bile acids, and lysophosphatidylinositol significantly increased compared to baseline; the levels of carboxylates and hypotaurine declined. In addition, 37 pathways principally associated with the metabolism of amino acids, carbohydrates, and glycan altered at treatment completion. The potential of each DM for diagnosing TB was examined using a cohort consisting of TB patients, those with latent infections, and controls. Logistic regression revealed four biomarkers (taurine, methionine, glutamine, and acetyl-carnitine) that exhibited excellent performance in differential diagnosis. In conclusion, we identified metabolites that could serve as useful metabolic signatures for TB management and elucidated underlying biological processes affected by the crosstalk between host and TB pathogen during treatment.

Effect of HNF4α genetic polymorphism G60D on the pharmacokinetics of CYP2D6 substrate tolterodine in healthy Korean individuals.

Hepatocyte nuclear receptor 4α (HNF4α) plays a central role in regulating human drug-metabolizing enzymes. Our previous study suggested that the newly identified polymorphism G60D in the HNF4α gene may decrease its downstream CYP2D6 activity in Asians. To confirm this effect in a clinical setting, we carried out a full pharmacokinetic study of a single oral dose of CYP2D6 substrate tolterodine in 30 healthy Korean individuals (HNF4α wild type: n = 24; HNF4α G60D heterozygotes: n = 6) who were pregenotyped for CYP2D6. Our study showed HNF4α G60D to be an independent predictor for increased AUC0-∞, C max of tolterodine and increased AUC0-∞ of the active moiety (tolterodine+5-hydroxymethyl-tolterodine) (P<0.05). A significant proportion of the variance in these parameters (R = 0.81, 0.59, and 0.63, respectively; P<0.01) was explained together by CYP2D6 and HNF4α genotypes. Further investigation of HNF4α genetic polymorphisms may improve the predictability of CYP2D6 activity in different populations.

Impact of the CYP2C19*17 polymorphism on the clinical outcome of clopidogrel therapy in Asian patients undergoing percutaneous coronary intervention.

The impact of the CYP2C19*17 polymorphism on the clinical outcome in Asians undergoing percutaneous coronary intervention (PCI) is unknown. We sought to assess the long-term impact of CYP2C19*17 on the risk for adverse clinical events in 2188 Korean patients taking clopidogrel after PCI. The prevalence of the CYP2C19*17 allele [*wt/*17: 2.4% (n = 53), *17/*17: 0%] was very low. The 2-year cumulative event rates for bleeding [*wt/*17 vs. *wt/*wt: 2 vs. 2.3%; adjusted hazard ratio (HR), 1.23; 95% confidence interval (CI), 0.16-9.45], stent thrombosis (2 vs. 1.1%; HR, 3.98; 95% CI, 0.49-31.6) or composite of any death, and myocardial infarction or stroke (5.4 vs. 7.1%; HR, 1.37; 95% CI, 0.32-5.73) did not differ on the basis of the presence of CYP2C19*17. In conclusion, in our study population of Asian patients, the CYP2C19*17 polymorphism was not associated with adverse clinical outcomes after PCI because of its low prevalence, the rarity of homozygotes, and the relatively low rate of adverse clinical events.

Effects of clopidogrel and itraconazole on the disposition of efavirenz and its hydroxyl metabolites: exploration of a novel CYP2B6 phenotyping index.

AIMS: To evaluate the effects of clopidogrel and itraconazole on the disposition of efavirenz and its hydroxyl metabolites in relation to the CYP2B6*6 genotype and explore potential phenotyping indices for CYP2B6 activity in vivo using a low dose of oral efavirenz. METHODS: We conducted a randomized three phase crossover study in 17 healthy Korean subjects pre-genotyped for the CYP2B6*6 allele (CYP2B6*1/*1, n = 6; *1/*6, n = 6; *6/*6, n = 5). Subjects were pretreated with clopidogrel (75 mg day(-1) for 4 days), itraconazole (200 mg day(-1) for 6 days), or placebo and then given a single dose of efavirenz (200 mg). The plasma (0-120 h) and urine (0-24 h) concentrations of efavirenz and its metabolites (7- and 8-hydroxyefavirenz and 8,14-dihydroxyefavirenz) were determined by LC/MS/MS. RESULTS: This study is the first to delineate quantitatively the full (phase I and II) metabolic profile of efavirenz and its three hydroxyl metabolites in humans. Clopidogrel pretreatment markedly decreased AUC(0,48 h), C(max) and Ae(0,24 h) for 8,14-dihydroxyefavirenz, compared with placebo; 95% CI of the ratios were 0.55, 0.73, 0.30, 0.45 and 0.25, 0.47, respectively. The 8,14-dihydroxyefavirenz : efavirenz AUC(0,120 h) ratio was significantly correlated with the weight-adjusted CL/F of efavirenz (r(2) ≈ 0.4, P < 0.05), differed with CYP2B6*6 genotype and was affected by clopidogrel pretreatment (P < 0.05) but not by itraconazole pretreatment. CONCLUSIONS: The disposition of 8,14-dihydroxy-EFV appears to be sensitive to CYP2B6 activity alterations in human subjects. The 8,14-dihydroxyefaviremz : efavirenz AUC(0,120 h) ratio is attractive as a candidate phenotyping index for CYP2B6 activity in vivo.

Effects of genetic polymorphisms of OPRM1, ABCB1, CYP3A4/5 on postoperative fentanyl consumption in Korean gynecologic patients.

OBJECTIVE: Fentanyl, a µ-opioid receptor agonist, is a substrate of P-glycoprotein. Its metabolism is catalyzed by CYP3A4 and CYP3A5. The aim of this study was to investigate the association between postoperative fentanyl consumption and genetic polymorphisms of µ-opioid receptor (OPRM1), ABCB1 (gene encoding P-glycoprotein), CYP3A4 and CYP3A5 in Korean patients. METHODS: 196 female patients scheduled to undergo total abdominal hysterectomy or laparoscopic assisted vaginal hysterectomy under general anesthesia were enrolled in this study. Intravenous patient-controlled analgesia with fentanyl was provided postoperatively. Cumulative fentanyl consumption was measured during the first 48 hours postoperatively. The severity of pain at rest was assessed with the visual analogue scale. OPRM1 118A>G, ABCB1 2677G>A/T, ABCB1 3435C>T, CYP3A4*18 and CYP3A5*3 variant alleles were genotyped. The effects of genetic and non-genetic factors on fentanyl requirements were evaluated with multiple linear regression analysis. RESULTS: The 24-hour cumulative fentanyl doses were significantly associated with pain core, weight and type of surgery (p < 0.05). The 48-hour cumulative fentanyl doses were significantly associated with pain score, type of surgery and history of PONV or motion sickness (p < 0.05). Genetic polymorphisms were not associated with fentanyl requirements. CONCLUSION: In Korean gynecologic patients, no association was found between genetic factors and postoperative fentanyl consumption.

A Phase II study of clinical outcomes of 3-week cycles of irinotecan and S-1 in patients with previously untreated metastatic colorectal cancer: influence of the UGT1A1 and CYP2A6 polymorphisms on clinical activity.

OBJECTIVES: We investigated the efficacy and safety of the combination of irinotecan (CPT-11) and S-1 (IRIS regimen) as a first-line treatment in patients with metastatic colorectal cancer. We also evaluated the association between UGT1A1 and CYP2A6 polymorphisms and clinical phenotypes. METHODS: The patients received CPT-11 (225 mg/m(2)) on day 1 and S-1 (80 mg/m(2)) on days 1-14 every 3 weeks. The association of the UGT1A1 (*6 and *28) and CYP2A6(*4, *7, *9, and *10) polymorphisms with toxicities and efficacy were analyzed. RESULTS: Thirty patients were treated. The overall response rate was 66.7% (95% CI 48.7-84.6). The median time to progression was 7.6 months (95% CI 5.8-9.5). The most common grade 3/4 hematologic and non-hematologic toxicity were neutropenia (53.4%) and diarrhea (16.7%), respectively. The allele frequencies of UGT1A1*6 and *28 were 15.5 and 10.3%, respectively. The frequencies of CYP2A6*4, *7, *9, and *10 were 15.5, 8.6, 29.3, and 3.5%, respectively. Stratification of patients according to the number of UGT1A1*28 and *6 alleles showed a significant correlation between the number of defective alleles and the incidence of grade 3/4 neutropenia. CONCLUSIONS: Our results indicate that IRIS is a promising first-line regimen in patients with metastatic colorectal cancer. Severe neutropenia may be associated with interindividual variations in UGT1A1 polymorphisms.