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Xu C, Jiang Z, Qian M, Zuo L, Xue H, Hu N. Influence of UDP-Glucuronosyltransferase Polymorphisms on Mycophenolic Acid Metabolism in Renal Transplant Patients. Transplant Proc 2024; 56:1280-1289. [PMID: 39054222 DOI: 10.1016/j.transproceed.2024.05.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Accepted: 05/24/2024] [Indexed: 07/27/2024]
Abstract
This study aimed to evaluate the effects of UDP-glucuronosyltransferase (UGT) polymorphisms on mycophenolic acid (MPA) metabolism in renal transplant patients. A total of 11 single nucleotide polymorphisms (SNPs) of UGT1A1, UGT1A7, UGT1A8, UGT1A9, UGT1A10, and UGT2B7 were genotyped in 79 renal transplant patients. The associations of SNPs and clinical factors with dose-adjusted MPA area under the plasma concentration-time curve (AUC/D), the dose-adjusted plasma concentration (C0/D) of 7-O-MPA-glucuronide (MPAG), and the dose-adjusted plasma concentration (C0/D) of acyl MPAG (AcMPAG) were analyzed. In the univariate analysis, UGT1A1 rs4148323, age, and anion gap were associated with MPA AUC/D. MPA AUC/D was higher in patients with the GA genotype of UGT1A1 rs4148323 compared to patients with the GG genotype. UGT1A1 rs4148323, UGT1A9 rs2741049 and clinical factors, including age, serum total bilirubin, adenosine deaminase, anion gap, urea, and creatinine, were associated with MPAG C0/D. UGT2B7 rs7438135, UGT2B7 rs7439366, and UGT2B7 rs7662029 also were associated with AcMPAG C0/D. Multiple linear regression analysis showed that UGT1A9 rs2741049 and indirect bilirubin were negatively correlated with MPAG C0/D (P = .001; P = .039), and UGT2B7 rs7662029 was positively correlated with AcMPAG C0/D (P = .008). This study demonstrates a significant influence of UGT1A9 rs2741049 and UGT2B7 rs7662029 polymorphisms on the metabolism of MPA in vivo.
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Affiliation(s)
- Caomei Xu
- Department of Pharmacy, The Third Affiliated Hospital of Soochow University, Changzhou, Jiangsu Province, China
| | - Zhenwei Jiang
- Department of Pharmacy, The Third Affiliated Hospital of Soochow University, Changzhou, Jiangsu Province, China
| | - Minyan Qian
- Department of Pharmacy, The Third Affiliated Hospital of Soochow University, Changzhou, Jiangsu Province, China
| | - Li'an Zuo
- Department of Pharmacy, The Third Affiliated Hospital of Soochow University, Changzhou, Jiangsu Province, China
| | - Hui Xue
- Department of Pharmacy, The Third Affiliated Hospital of Soochow University, Changzhou, Jiangsu Province, China.
| | - Nan Hu
- Department of Pharmacy, The Third Affiliated Hospital of Soochow University, Changzhou, Jiangsu Province, China.
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Yow HY, Ikawati M, Siswanto S, Hermawan A, Rahmat AK, Tan JSL, Tee YC, Ng KP, Ikawati Z. Influence of genetic polymorphisms on pharmacokinetics and treatment response of mycophenolic acid: a scoping review. Pharmacogenomics 2024; 25:259-288. [PMID: 38884938 PMCID: PMC11388138 DOI: 10.1080/14622416.2024.2344430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2024] [Accepted: 04/12/2024] [Indexed: 06/18/2024] Open
Abstract
This scoping review explores the impact of genetic polymorphisms on the pharmacokinetics and treatment responses of mycophenolic acid (MPA), an immunosuppressant. The study includes 83 articles from 1226 original studies, focusing on transplantation (n = 80) and autoimmune disorders (n = 3). Genetic variants in uridine 5'-diphospho-glucuronosyltransferase (UGT1A9, UGT1A8 and UGT2B7) and transmembrane transporters (ABCC2, SLCO1B1, SLCO1B3 and ABCB1) significantly affected MPA's pharmacokinetics and susceptibility to its adverse effect. Whereas variants in several genes including UGT1A9, UGT2B7, IMPDH1 and IMPDH2 have been associated with a higher risk of transplant rejection. However, there is a lack of studies on MPA's impact on autoimmune disorders and limited research on the Asian population. The findings underscore the need for further research on MPA's impact across different populations and diseases, particularly among other Asian ethnic groups, to advance personalized medicine in MPA therapy.
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Affiliation(s)
- Hui-Yin Yow
- Department of Pharmaceutical Life Sciences, Faculty of Pharmacy, Universiti Malaya, Kuala Lumpur, 50603, Malaysia
| | - Muthi Ikawati
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Universitas Gadjah Mada, Daerah Istimewa Yogyakarta, 55281, Indonesia
| | - Soni Siswanto
- Department of Pharmacology & Clinical Pharmacy, Faculty of Pharmacy, Universitas Gadjah Mada, Daerah Istimewa Yogyakarta, 55281, Indonesia
| | - Adam Hermawan
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Universitas Gadjah Mada, Daerah Istimewa Yogyakarta, 55281, Indonesia
- Advanced Pharmaceutical Sciences Laboratory, Faculty of Pharmacy, Universitas Gadjah Mada, Daerah Istimewa Yogyakarta, 55281, Indonesia
| | - Alim Khodimul Rahmat
- Department of Pharmacology & Clinical Pharmacy, Faculty of Pharmacy, Universitas Gadjah Mada, Daerah Istimewa Yogyakarta, 55281, Indonesia
| | - Janet Sui-Ling Tan
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Universiti Malaya, Kuala Lumpur, 50603, Malaysia
| | - Ying-Chew Tee
- Rheumatology Unit, Department of Medicine, University Malaya, Kuala Lumpur, 50603, Malaysia
| | - Kok-Peng Ng
- Nephrology Unit, Department of Medicine, University Malaya, Kuala Lumpur, 50603, Malaysia
| | - Zullies Ikawati
- Department of Pharmacology & Clinical Pharmacy, Faculty of Pharmacy, Universitas Gadjah Mada, Daerah Istimewa Yogyakarta, 55281, Indonesia
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3
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Miranda C, Galleguillos M, Torres R, Tardón K, Cáceres DD, Lee K, Redal MA, Varela NM, Quiñones LA. Preliminary Pharmacogenomic-Based Predictive Models of Tamoxifen Response in Hormone-dependent Chilean Breast Cancer Patients. Front Pharmacol 2021; 12:661443. [PMID: 34899282 PMCID: PMC8656167 DOI: 10.3389/fphar.2021.661443] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 10/25/2021] [Indexed: 12/15/2022] Open
Abstract
Tamoxifen (TAM), a selective oestrogen receptor modulator, is one of the most used treatments in oestrogen receptor-positive (ER+) early and metastatic breast cancer (BC) patients. The response to TAM has a high degree of inter-individual variability. This is mainly due to genetic variants in CYP2D6 gene, as well as other genes encoding proteins involved in the TAM pharmacokinetic and/or pharmacodynamic. Therefore, prediction of the TAM response using these genetic factors together with other non-genetic variables may be relevant to improve breast cancer treatment. Thus, in this work, we used genetic polymorphisms and clinical variables for TAM response modelling. One hundred sixty-two ER + BC patients with 2 years of TAM treatment were retrospectively recruited, and the genetic polymorphisms CYP2D6*4, CYP3A4*1B (CYP3A4*1.001), CYP3A5*3, UGT2B7*2, UGT2B15*2, SULT1A1*2, and ESRA V364E were analyzed by PCR-RFLP. Concomitantly, the therapeutic response was obtained from clinical records for association with genotypes using univariate and multivariate biostatistical models. Our results show that UGT2B15*1/*2 genotype protects against relapse (OR = 0.09; p = 0.02), CYP3A5*3/*3 genotype avoids endometrial hyperplasia (OR = 0.07; p = 0.01), SULT1A1*1/*2 genotype avoids vaginal bleeding (OR = 0.09; p = 0.03) and ESRA 364E/364E genotype increases the probability of vaginal bleeding (OR = 5.68; p = 0.02). Logistic regression models, including genomic and non-genomic variables, allowed us to obtain preliminary predictive models to explain relapse (p = 0.010), endometrial hyperplasia (p = 0.002) and vaginal bleeding (p = 0.014). Our results suggest that the response to TAM treatment in ER + BC patients might be associated with the presence of the studied genetic variants in UGT2B15, CYP3A5, SULT1A1 and ESRA genes. After clinical validation protocols, these models might be used to help to predict a percentage of BC relapse and adverse reactions, improving the individual response to TAM-based treatment.
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Affiliation(s)
- Carla Miranda
- Laboratory of Chemical Carcinogenesis and Pharmacogenetics, Department of Basic-Clinical Oncology (DOBC), Faculty of Medicine, University of Chile, Santiago, Chile
| | - Macarena Galleguillos
- Laboratory of Chemical Carcinogenesis and Pharmacogenetics, Department of Basic-Clinical Oncology (DOBC), Faculty of Medicine, University of Chile, Santiago, Chile
| | | | | | - Dante D Cáceres
- Institute of Population Health, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Kuen Lee
- Laboratory of Chemical Carcinogenesis and Pharmacogenetics, Department of Basic-Clinical Oncology (DOBC), Faculty of Medicine, University of Chile, Santiago, Chile.,Faculty of Medicine, University of Chile, Santiago, Chile
| | - María A Redal
- Genetic Division, Department of Medicine, Hospital de Clínicas José de San Martín, Buenos Aires, Argentina.,Latin American Network for Implementation and Validation of Clinical Pharmacogenomics Guidelines (RELIVAF-CYTED), Madrid, Spain
| | - Nelson M Varela
- Laboratory of Chemical Carcinogenesis and Pharmacogenetics, Department of Basic-Clinical Oncology (DOBC), Faculty of Medicine, University of Chile, Santiago, Chile.,Latin American Network for Implementation and Validation of Clinical Pharmacogenomics Guidelines (RELIVAF-CYTED), Madrid, Spain
| | - Luis A Quiñones
- Laboratory of Chemical Carcinogenesis and Pharmacogenetics, Department of Basic-Clinical Oncology (DOBC), Faculty of Medicine, University of Chile, Santiago, Chile.,Latin American Network for Implementation and Validation of Clinical Pharmacogenomics Guidelines (RELIVAF-CYTED), Madrid, Spain
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Jiang Z, Hu N. Effect of UGT polymorphisms on pharmacokinetics and adverse reactions of mycophenolic acid in kidney transplant patients. Pharmacogenomics 2021; 22:1019-1040. [PMID: 34581204 DOI: 10.2217/pgs-2021-0087] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Mycophenolic acid (MPA) is a common immunosuppressive drug for kidney transplantation patients, and is characterized by a narrow therapeutic index and significant individual variability. UGTs are the main enzymes responsible for the metabolism of MPA. Although, many studies have focused on the relationship between UGT polymorphisms and pharmacokinetics and adverse reactions of MPA, the conclusion are controversial. We reviewed the relevant literature and summarized the significant influences of UGT polymorphisms, such as UGT1A8 (rs1042597, rs17863762), UGT1A9 (rs72551330, rs6714486, rs17868320, rs2741045, rs2741045) and UGT2B7 (rs7438135, rs7439366, rs7662029), on the pharmacokinetics of MPA and its metabolites and adverse reactions. The review provides a reference for guiding the individualized administration of MPA and reducing adverse reactions to MPA.
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Affiliation(s)
- Zhenwei Jiang
- Department of Pharmacy, The Third Affiliated Hospital of Soochow University, Jiangsu Province, Changzhou, 213000, China
| | - Nan Hu
- Department of Pharmacy, The Third Affiliated Hospital of Soochow University, Jiangsu Province, Changzhou, 213000, China
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Yang CL, Sheng CC, Liao GY, Su Y, Feng LJ, Xia Q, Jiao Z, Xu DJ. Genetic polymorphisms in metabolic enzymes and transporters have no impact on mycophenolic acid pharmacokinetics in adult kidney transplant patients co-treated with tacrolimus: A population analysis. J Clin Pharm Ther 2021; 46:1564-1575. [PMID: 34312870 DOI: 10.1111/jcpt.13488] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 05/05/2021] [Accepted: 07/01/2021] [Indexed: 12/17/2022]
Abstract
WHAT IS KNOWN AND OBJECTIVE Mycophenolate mofetil, an ester prodrug of mycophenolic acid (MPA), is widely used to prevent graft rejection after kidney transplantation. The pharmacokinetic (PK) of MPA has been extensively studied, which revealed a high degree of variability. An integrated population PK (PopPK) model of MPA and its main metabolite mycophenolic acid glucuronide (MPAG) was developed using the adult patients who underwent kidney transplant and were administered oral mycophenolate mofetil combined with tacrolimus. METHODS In total, 917 MPA and 740 MPAG concentrations in191 adult patients were analysed via nonlinear mixed-effects modelling. The concentration-time data were adequately described using a chain compartment model, including central and peripheral compartments for MPA and a central compartment for MPAG. Stepwise forward inclusion and backward elimination procedures were used to investigate the effects of genetic polymorphisms, including in UGT1A8, UGT1A9, UGT2B7, ABCB1, ABCC2, ABCG2, SLCO1B1, SLCO1B3, and HNF1α. RESULTS AND DISCUSSION These genetic polymorphisms in metabolic enzymes and transporters have no obvious impact on the PK of MPA in adult patients who underwent kidney transplant and were co-treated with tacrolimus. The post-transplant time, serum albumin, and creatinine clearance were identified as significant covariates affecting the PK of MPA and MPAG, which should be considered in the clinical use of mycophenolate mofetil. WHAT IS NEW AND CONCLUSION We established a PopPK model of MPA and MPAG in Chinese adult patients who underwent kidney transplant and were co-treated with tacrolimus. Genetic polymorphisms in metabolic enzymes and transporters showed no obvious impact on MMF PK. A model-informed dosing strategy was proposed by the established model, and MMF dose adjustment should be based on ALB levels and the post-transplantation time.
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Affiliation(s)
- Chun-Lan Yang
- Department of Pharmacy, the First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Chang-Cheng Sheng
- Department of Pharmacy, Guizhou Provincial People's Hospital, Guiyang, China
| | - Gui-Yi Liao
- Department of Urology, the First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Yong Su
- Department of Pharmacy, the First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Li-Juan Feng
- Department of Pharmacy, the First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Quan Xia
- Department of Pharmacy, the First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Zheng Jiao
- Department of Pharmacy, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Du-Juan Xu
- Department of Pharmacy, the First Affiliated Hospital of Anhui Medical University, Hefei, China
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6
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Na Takuathung M, Sakuludomkan W, Koonrungsesomboon N. The Impact of Genetic Polymorphisms on the Pharmacokinetics and Pharmacodynamics of Mycophenolic Acid: Systematic Review and Meta-analysis. Clin Pharmacokinet 2021; 60:1291-1302. [PMID: 34105062 DOI: 10.1007/s40262-021-01037-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/11/2021] [Indexed: 01/14/2023]
Abstract
BACKGROUND Mycophenolic acid (MPA) is among the most commonly prescribed medications for immunosuppression following organ transplantation. Highly variable MPA exposure and drug response are observed among individuals receiving the same dosage of the drug. Identification of candidate genes whose polymorphisms could be used to predict MPA exposure and clinical outcome is of clinical value. OBJECTIVES This study aimed to determine the impact of genetic polymorphisms on the pharmacokinetics and pharmacodynamics of MPA in humans by means of a systematic review and meta-analysis. METHODS A systematic search was conducted on PubMed, EMBASE, Web of Sciences, Scopus, and the Cochrane Library databases. A meta-analysis was conducted to determine any associations between genetic polymorphisms and pharmacokinetic or pharmacodynamic parameters of MPA. Pooled-effect estimates were calculated by means of the random-effects model. RESULTS A total of 37 studies involving 3844 individuals were included in the meta-analysis. Heterozygous carriers of the UGT1A9 -275T>A polymorphism were observed to have a significantly lower MPA exposure than wild-type individuals. Four single nucleotide polymorphisms (SNPs), namely UGT1A9 -2152C>T, UGT1A8 518C>G, UGT2B7 211G>T, and SLCO1B1 521T>C, were also significantly associated with altered MPA pharmacokinetics. However, none of the investigated SNPs, including SNPs in the IMPDH gene, were found to be associated with the clinical efficacy of MPA. The only SNP that was associated with adverse outcomes was SLCO1B3 344T>G. CONCLUSIONS The present systematic review and meta-analysis identified six SNPs that were significantly associated with pharmacokinetic variability or adverse effects of MPA. Our findings represent the basis for future research and clinical implications with regard to the role of pharmacogenetics in MPA pharmacokinetics and drug response.
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Affiliation(s)
- Mingkwan Na Takuathung
- Department of Pharmacology, Faculty of Medicine, Chiang Mai University, 110 Intawaroros Road, Sriphoom, Muang, Chiang Mai, 50200, Thailand
| | - Wannachai Sakuludomkan
- Department of Pharmacology, Faculty of Medicine, Chiang Mai University, 110 Intawaroros Road, Sriphoom, Muang, Chiang Mai, 50200, Thailand
| | - Nut Koonrungsesomboon
- Department of Pharmacology, Faculty of Medicine, Chiang Mai University, 110 Intawaroros Road, Sriphoom, Muang, Chiang Mai, 50200, Thailand.
- Musculoskeletal Science and Translational Research (MSTR) Center, , Chiang Mai University, Muang, Chiang Mai, Thailand.
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Significance of Ethnic Factors in Immunosuppressive Therapy Management After Organ Transplantation. Ther Drug Monit 2021; 42:369-380. [PMID: 32091469 DOI: 10.1097/ftd.0000000000000748] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Clinical outcomes after organ transplantation have greatly improved in the past 2 decades with the discovery and development of immunosuppressive drugs such as calcineurin inhibitors, antiproliferative agents, and mammalian target of rapamycin inhibitors. However, individualized dosage regimens have not yet been fully established for these drugs except for therapeutic drug monitoring-based dosage modification because of extensive interindividual variations in immunosuppressive drug pharmacokinetics. The variations in immunosuppressive drug pharmacokinetics are attributed to interindividual variations in the functional activity of cytochrome P450 enzymes, UDP-glucuronosyltransferases, and ATP-binding cassette subfamily B member 1 (known as P-glycoprotein or multidrug resistance 1) in the liver and small intestine. Some genetic variations have been found to be involved to at least some degree in pharmacokinetic variations in post-transplant immunosuppressive therapy. It is well known that the frequencies and effect size of minor alleles vary greatly between different races. Thus, ethnic considerations might provide useful information for optimizing individualized immunosuppressive therapy after organ transplantation. Here, we review ethnic factors affecting the pharmacokinetics of immunosuppressive drugs requiring therapeutic drug monitoring, including tacrolimus, cyclosporine, mycophenolate mofetil, sirolimus, and everolimus.
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Bergan S, Brunet M, Hesselink DA, Johnson-Davis KL, Kunicki PK, Lemaitre F, Marquet P, Molinaro M, Noceti O, Pattanaik S, Pawinski T, Seger C, Shipkova M, Swen JJ, van Gelder T, Venkataramanan R, Wieland E, Woillard JB, Zwart TC, Barten MJ, Budde K, Dieterlen MT, Elens L, Haufroid V, Masuda S, Millan O, Mizuno T, Moes DJAR, Oellerich M, Picard N, Salzmann L, Tönshoff B, van Schaik RHN, Vethe NT, Vinks AA, Wallemacq P, Åsberg A, Langman LJ. Personalized Therapy for Mycophenolate: Consensus Report by the International Association of Therapeutic Drug Monitoring and Clinical Toxicology. Ther Drug Monit 2021; 43:150-200. [PMID: 33711005 DOI: 10.1097/ftd.0000000000000871] [Citation(s) in RCA: 92] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 01/29/2021] [Indexed: 12/13/2022]
Abstract
ABSTRACT When mycophenolic acid (MPA) was originally marketed for immunosuppressive therapy, fixed doses were recommended by the manufacturer. Awareness of the potential for a more personalized dosing has led to development of methods to estimate MPA area under the curve based on the measurement of drug concentrations in only a few samples. This approach is feasible in the clinical routine and has proven successful in terms of correlation with outcome. However, the search for superior correlates has continued, and numerous studies in search of biomarkers that could better predict the perfect dosage for the individual patient have been published. As it was considered timely for an updated and comprehensive presentation of consensus on the status for personalized treatment with MPA, this report was prepared following an initiative from members of the International Association of Therapeutic Drug Monitoring and Clinical Toxicology (IATDMCT). Topics included are the criteria for analytics, methods to estimate exposure including pharmacometrics, the potential influence of pharmacogenetics, development of biomarkers, and the practical aspects of implementation of target concentration intervention. For selected topics with sufficient evidence, such as the application of limited sampling strategies for MPA area under the curve, graded recommendations on target ranges are presented. To provide a comprehensive review, this report also includes updates on the status of potential biomarkers including those which may be promising but with a low level of evidence. In view of the fact that there are very few new immunosuppressive drugs under development for the transplant field, it is likely that MPA will continue to be prescribed on a large scale in the upcoming years. Discontinuation of therapy due to adverse effects is relatively common, increasing the risk for late rejections, which may contribute to graft loss. Therefore, the continued search for innovative methods to better personalize MPA dosage is warranted.
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Affiliation(s)
- Stein Bergan
- Department of Pharmacology, Oslo University Hospital and Department of Pharmacy, University of Oslo, Oslo, Norway
| | - Mercè Brunet
- Pharmacology and Toxicology Laboratory, Biochemistry and Molecular Genetics Department, Biomedical Diagnostic Center, Hospital Clinic of Barcelona, University of Barcelona, IDIBAPS, CIBERehd, Spain
| | - Dennis A Hesselink
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus MC, University Medical Center Rotterdam, The Netherlands
| | - Kamisha L Johnson-Davis
- Department of Pathology, University of Utah Health Sciences Center and ARUP Laboratories, Salt Lake City, Utah
| | - Paweł K Kunicki
- Department of Drug Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Warszawa, Poland
| | - Florian Lemaitre
- Univ Rennes, CHU Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail)-UMR_S 1085, Rennes, France
| | - Pierre Marquet
- INSERM, Université de Limoges, Department of Pharmacology and Toxicology, CHU de Limoges, U1248 IPPRITT, Limoges, France
| | - Mariadelfina Molinaro
- Clinical and Experimental Pharmacokinetics Lab, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Ofelia Noceti
- National Center for Liver Tansplantation and Liver Diseases, Army Forces Hospital, Montevideo, Uruguay
| | | | - Tomasz Pawinski
- Department of Drug Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Warszawa, Poland
| | | | - Maria Shipkova
- Synlab TDM Competence Center, Synlab MVZ Leinfelden-Echterdingen GmbH, Leinfelden-Echterdingen, Germany
| | - Jesse J Swen
- Department of Clinical Pharmacy & Toxicology, Leiden University Medical Center, Leiden, The Netherlands
| | - Teun van Gelder
- Department of Clinical Pharmacy & Toxicology, Leiden University Medical Center, Leiden, The Netherlands
| | - Raman Venkataramanan
- Department of Pharmaceutical Sciences, School of Pharmacy and Department of Pathology, Starzl Transplantation Institute, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Eberhard Wieland
- Synlab TDM Competence Center, Synlab MVZ Leinfelden-Echterdingen GmbH, Leinfelden-Echterdingen, Germany
| | - Jean-Baptiste Woillard
- INSERM, Université de Limoges, Department of Pharmacology and Toxicology, CHU de Limoges, U1248 IPPRITT, Limoges, France
| | - Tom C Zwart
- Department of Clinical Pharmacy & Toxicology, Leiden University Medical Center, Leiden, The Netherlands
| | - Markus J Barten
- Department of Cardiac- and Vascular Surgery, University Heart and Vascular Center Hamburg, Hamburg, Germany
| | - Klemens Budde
- Department of Nephrology, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Maja-Theresa Dieterlen
- Department of Cardiac Surgery, Heart Center, HELIOS Clinic, University Hospital Leipzig, Leipzig, Germany
| | - Laure Elens
- Integrated PharmacoMetrics, PharmacoGenomics and PharmacoKinetics (PMGK) Research Group, Louvain Drug Research Institute (LDRI), Université Catholique de Louvain (UCLouvain), Brussels, Belgium
| | - Vincent Haufroid
- Louvain Centre for Toxicology and Applied Pharmacology (LTAP), Institut de Recherche Expérimentale et Clinique, UCLouvain and Department of Clinical Chemistry, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Satohiro Masuda
- Department of Pharmacy, International University of Health and Welfare Narita Hospital, Chiba, Japan
| | - Olga Millan
- Pharmacology and Toxicology Laboratory, Biochemistry and Molecular Genetics Department, Biomedical Diagnostic Center, Hospital Clinic of Barcelona, University of Barcelona, IDIBAPS, CIBERehd, Spain
| | - Tomoyuki Mizuno
- Division of Clinical Pharmacology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Dirk J A R Moes
- Department of Clinical Pharmacy & Toxicology, Leiden University Medical Center, Leiden, The Netherlands
| | - Michael Oellerich
- Department of Clinical Pharmacology, University Medical Center Göttingen, Georg-August-University Göttingen, Göttingen, Germany
| | - Nicolas Picard
- INSERM, Université de Limoges, Department of Pharmacology and Toxicology, CHU de Limoges, U1248 IPPRITT, Limoges, France
| | | | - Burkhard Tönshoff
- Department of Pediatrics I, University Children's Hospital, Heidelberg, Germany
| | - Ron H N van Schaik
- Department of Clinical Chemistry, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Nils Tore Vethe
- Department of Pharmacology, Oslo University Hospital and Department of Pharmacy, University of Oslo, Oslo, Norway
| | - Alexander A Vinks
- Department of Pharmacy, International University of Health and Welfare Narita Hospital, Chiba, Japan
| | - Pierre Wallemacq
- Clinical Chemistry Department, Cliniques Universitaires St Luc, Université Catholique de Louvain, LTAP, Brussels, Belgium
| | - Anders Åsberg
- Department of Transplantation Medicine, Oslo University Hospital-Rikshospitalet and Department of Pharmacy, University of Oslo, Oslo, Norway; and
| | - Loralie J Langman
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
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Gao S, Bell EC, Zhang Y, Liang D. Racial Disparity in Drug Disposition in the Digestive Tract. Int J Mol Sci 2021; 22:1038. [PMID: 33494365 PMCID: PMC7865938 DOI: 10.3390/ijms22031038] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/17/2021] [Accepted: 01/18/2021] [Indexed: 12/13/2022] Open
Abstract
The major determinants of drug or, al bioavailability are absorption and metabolism in the digestive tract. Genetic variations can cause significant differences in transporter and enzyme protein expression and function. The racial distribution of selected efflux transporter (i.e., Pgp, BCRP, MRP2) and metabolism enzyme (i.e., UGT1A1, UGT1A8) single nucleotide polymorphisms (SNPs) that are highly expressed in the digestive tract are reviewed in this paper with emphasis on the allele frequency and the impact on drug absorption, metabolism, and in vivo drug exposure. Additionally, preclinical and clinical models used to study the impact of transporter/enzyme SNPs on protein expression and function are also reviewed. The results showed that allele frequency of the major drug efflux transporters and the major intestinal metabolic enzymes are highly different in different races, leading to different drug disposition and exposure. The conclusion is that genetic polymorphism is frequently observed in different races and the related protein expression and drug absorption/metabolism function and drug in vivo exposure can be significantly affected, resulting in variations in drug response. Basic research on race-dependent drug absorption/metabolism is expected, and FDA regulations of drug dosing adjustment based on racial disparity are suggested.
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Affiliation(s)
- Song Gao
- Department of Pharmaceutical Science, College of Pharmacy and Health Sciences, Texas Southern University, 3100 Cleburne Street, Houston, TX 77004, USA; (E.C.B.); (Y.Z.); (D.L.)
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Population pharmacokinetics and Bayesian estimation of mycophenolic acid concentrations in Chinese adult renal transplant recipients. Acta Pharmacol Sin 2017; 38:1566-1579. [PMID: 28836585 DOI: 10.1038/aps.2017.115] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 05/10/2017] [Indexed: 12/19/2022] Open
Abstract
Mycophenolate mofetil (MMF) is an important immunosuppressant used in renal transplantation, and mycophenolic acid (MPA) is the active component released from the ester prodrug MMF. The objective of this study was to investigate the population pharmacokinetics of mycophenolic acid (MPA) following oral administration of MMF in Chinese adult renal transplant recipients and to identify factors that explain MPA pharmacokinetic variability. Pharmacokinetic data for MPA and covariate information were retrospectively collected from 118 patients (79 patients were assigned to the group for building the population pharmacokinetic model, while 39 patients were assigned to the validation group). Population pharmacokinetic data analysis was performed using the NONMEM software. The pharmacokinetics of MPA was best described by a two-compartment model with a first-order absorption rate with no lag time. Body weight and serum creatinine level were positively correlated with apparent clearance (CL/F). The polymorphism in uridine diphosphate glucuronosyltransferase gene, UGT2B7, significantly explained the interindividual variability in the initial volume of distribution (V1/F). The estimated population parameters (and interindividual variability) were CL/F 18.3 L/h (34.2%) and V1/F 27.9 L (21.3%). The interoccasion variability was 13.7%. These population pharmacokinetic data have significant clinical value for the individualization of MMF therapy in Chinese adult renal transplant patients.
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11
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Iemsupakkul P, Kongchareonsombat W, Kijvikai K. Comparison of Pfannenstiel or Extended Iliac Port Site Kidney Extraction in Laparoscopic Donor Nephrectomy: Do We Have Consensus? EXP CLIN TRANSPLANT 2017; 16:466-472. [PMID: 28338459 DOI: 10.6002/ect.2017.0017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVES Our objective was to compare the outcomes of the different extraction sites between extended iliac port site incision and Pfannenstiel incision during laparoscopic donor nephrectomy. MATERIALS AND METHODS We prospectively evaluated patients who underwent laparoscopic donor nephrectomy from June 2014 to March 2015 at our institution. Perioperative parameters were included, with particular reference to warm ischemic time. The other parameters recorded included operative time, blood loss, hospital stay, analgesic requirement, and cosmetic results. RESULTS We analyzed a total of 41 patients. Kidney retrieval site of each patient was made randomly. Extraction sites were done by using extended iliac port site incisions in 23 patients and by Pfannenstiel incision in 18 patients. Mean warm ischemic time was 4.09 minutes with extended iliac port site incision versus 4.94 minutes with Pfannenstiel incision (P = .04). Mean operative time, blood loss, hospital stay, and analgesic requirements were comparable between the 2 groups. Mean cosmetic score was 10.39 with extended iliac port site versus 12.06 with Pfannenstiel incision. CONCLUSIONS Extraction with extended iliac port site incision had significantly less warm ischemic time than Pfannenstiel incision in laparoscopic donor nephrectomy. It was also not inferior to Pfannenstiel incision regarding the other.
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Affiliation(s)
- Paiboon Iemsupakkul
- Division of Urology, Department of Surgery, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
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Liu K, Gu S, Liu X, Sun Q, Wang Y, Meng J, Xu Z. Meta-analysis reveals a lack of association between MRP2 C-24T genetic polymorphism and the pharmacokinetics of mycophenolic acid in adult renal transplant recipients. Meta Gene 2017. [DOI: 10.1016/j.mgene.2016.12.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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13
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Chatzistefanidis D, Lazaros L, Giaka K, Nakou I, Tzoufi M, Georgiou I, Kyritsis A, Markoula S. UGT1A6- and UGT2B7-related valproic acid pharmacogenomics according to age groups and total drug concentration levels. Pharmacogenomics 2016; 17:827-35. [PMID: 27232006 DOI: 10.2217/pgs-2016-0014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
AIM The role of UGT1A6 and UGT2B7 polymorphisms and the impact of total drug plasma concentration in valproic acid (VPA) pharmacogenomics. PATIENTS & METHODS A total of 134 Greek patients were recruited (76 adults). Patients were genotyped for UGT1A6 19T>G, 541A>G and 552A>C and UGT2B7 802T>C polymorphisms. Patients' demographic and clinical data were registered. Natural logarithm of concentration-to-dose ratio (CDR) was also calculated as the final outcome. RESULTS No significant genotype-related differences in VPA metabolism were noted among various subgroups. An increased lnCDR ratio was noted in children patients compared with adults suggesting increased metabolic capability in younger ages. CONCLUSION UGT1A6 and UGT2B7 genotypes were not related to significant changes in VPA metabolism, even after controlling for total drug concentration levels. Younger ages were associated with increased VPA clearance rate.
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Affiliation(s)
| | - Leandros Lazaros
- Medical Genetics & Assisted Reproduction, University of Ioannina, Ioannina, Greece
| | - Katerina Giaka
- Medical Genetics & Assisted Reproduction, University of Ioannina, Ioannina, Greece
| | - Iliada Nakou
- Department of Pediatrics, University of Ioannina, Stavros Niarchos Avenue, 45500 Ioannina, Greece
| | - Meropi Tzoufi
- Department of Pediatrics, University of Ioannina, Stavros Niarchos Avenue, 45500 Ioannina, Greece
| | - Ioannis Georgiou
- Medical Genetics & Assisted Reproduction, University of Ioannina, Ioannina, Greece
| | | | - Sofia Markoula
- Department of Neurology, University of Ioannina, Ioannina, Greece
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14
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Xie XC, Li J, Wang HY, Li HL, Liu J, Fu Q, Huang JW, Zhu C, Zhong GP, Wang XD, Sun PP, Huang M, Wang CX, Li JL. Associations of UDP-glucuronosyltransferases polymorphisms with mycophenolate mofetil pharmacokinetics in Chinese renal transplant patients. Acta Pharmacol Sin 2015; 36:644-50. [PMID: 25864649 DOI: 10.1038/aps.2015.7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 02/12/2015] [Indexed: 12/25/2022] Open
Abstract
AIM To evaluate the effects of UDP-glucuronosyltransferases (UGTs) polymorphisms on the pharmacokinetics of the immunosuppressant mycophenolate mofetil (MMF) in Chinese renal transplant recipients. METHODS A total of 127 renal transplant patients receiving MMF were genotyped for polymorphisms in UGT1A9 -1818T>C, I399C>T, -118T9/10, -440C>T, -331T>C, UGT2B7 IVS1+985A>G, 211G>T, -900A>G, UGT1A8 518C>G and UGT1A7 622T>C. The plasma concentrations of the MMF active moiety mycophenolic acid (MPA) and main metabolite 7-O-MPA-glucuronide (MPAG) were analyzed using HPLC. Univariate and multivariate analyses were used to assess the effects of UGT-related gene polymorphisms on MPA pharmacokinetics. RESULTS The dose-adjusted MPA AUC0-12 h of the patients with the UGT2B7 IVS1+985AG genotype was 48% higher than that of the patients with the IVS1+985AA genotype, which could explain 11.2% of the inter-individual variation in MPA pharmacokinetics. The dose-adjusted MPAG AUC0-12 h of the patients with the UGT1A7 622CC and UGT1A9 -440CT/-331TC genotypes, respectively, was significantly higher than that of the patients with 622T homozygotes and -440C/-331T homozygotes. Furthermore, the genotypes UGT1A9 -1818T>C and UGT1A8 518C>G were associated with a low dose-adjusted MPAG AUC0-12 h. CONCLUSION The UGT2B7 11+985A>G genotype is associated with the pharmacokinetics of MPA in Chinese renal transplant patients, which demonstrates the usefulness of this SNP for individualizing MMF dosing.
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Pithukpakorn M, Tiwawanwong T, Lalerd Y, Assawamakin A, Premasathian N, Tasanarong A, Thongnoppakhun W, Vongwiwatana A. Mycophenolic acid AUC in Thai kidney transplant recipients receiving low dose mycophenolate and its association with UGT2B7 polymorphisms. PHARMACOGENOMICS & PERSONALIZED MEDICINE 2014; 7:379-85. [PMID: 25540593 PMCID: PMC4270037 DOI: 10.2147/pgpm.s72760] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Background Despite use of a lower mycophenolate dose in Thai kidney transplant patients, acceptable graft and patient outcomes can be achieved. We therefore examined the pharmacokinetics of mycophenolic acid (MPA) by area under the curve (AUC) and investigated genetic contribution in mycophenolate metabolism in this population. Methods Kidney transplant recipients with stable graft function who were receiving mycophenolate mofetil 1,000 mg/d in combination with either cyclosporine or tacrolimus, and prednisolone were studied. The MPA concentration was measured by fluorescence polarization immunoassay (FPIA), at predose and 1, 1.5, 2, 4, 6, 8, 10, and 12 hours after dosing. Genetic polymorphisms in UGT1A8, UGT1A9, and UGT2B7 were examined by denaturing high-performance liquid chromatography (DHPLC)-based single-base extension (SBE) analysis. Results A total 138 patients were included in study. The mean AUC was 39.49 mg-h/L (28.39–89.58 mg-h/L), which was in the therapeutic range. The correlation between the predose MPA concentration and AUC was poor. The mean AUC in the tacrolimus group was higher than that in the cyclosporine group. Polymorphisms in UGT2B7 showed significant association with AUC. Conclusion Most of our patients with reduced mycophenolate dose had the AUC within the therapeutic range. Genetic polymorphisms in UGT2B7 may play a role in MPA metabolism in Thai kidney transplant patients.
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Affiliation(s)
| | - Tiwat Tiwawanwong
- Division of Nephrology, Department of Medicine, Mahidol University, Bangkok, Thailand
| | - Yupaporn Lalerd
- Division of Molecular Genetics, Department of Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Anunchai Assawamakin
- Division of Molecular Genetics, Department of Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand ; Department of Pharmacology, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand
| | - Nalinee Premasathian
- Division of Nephrology, Department of Medicine, Mahidol University, Bangkok, Thailand
| | - Adis Tasanarong
- Department of Medicine, Faculty of Medicine, Thammasat University, Bangkok, Thailand
| | - Wanna Thongnoppakhun
- Division of Molecular Genetics, Department of Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Attapong Vongwiwatana
- Division of Nephrology, Department of Medicine, Mahidol University, Bangkok, Thailand
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A pilot study of leukocyte expression patterns for drug metabolizing enzyme and transporter transcripts in autoimmune glomerulonephritis. Int J Clin Pharmacol Ther 2014; 52:303-13. [PMID: 24548980 PMCID: PMC4123858 DOI: 10.5414/cp201972] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/20/2014] [Indexed: 01/11/2023] Open
Abstract
OBJECTIVE Leukocyte mRNA expression patterns of drug metabolizing enzyme genes and transporter genes that are relevant for the disposition of cyclophosphamide and mycophenolate were studied. The relationships between expression and patient-level data and pharmacokinetics were evaluated. METHODS The study included patients with glomerulonephritis secondary to lupus nephritis (SLE, n = 36), small vessel vasculitis (SVV, n = 35), healthy controls (HC, n = 10), and disease controls (VC, n = 5; LC, n = 5). Transcript assays targeted metabolizing enzymes (UGT1A7, UGT1A9, UGT2B7, CYP3A4, CYP2C9, CYP2B6) and transporters (ABCB1, ABCC2, ABCG2, SLCO1A2). Genotyping for specific variants was conducted. Group transcript fold-changes were evaluated. Patient level data was evaluated for transcript foldchange and disease, treatment, gender, race, and genotype. RESULTS Significant differences were noted in expression of UGT1A7, ABCB1, and ABCC2; for UGT1A7, SVV (0.17 ± 0.42; p < 0.05) and SLE (0.03 ± 0.1; p < 0.05) groups had lower expression than HC (0.79 ± 2.02). For ABCB1, SLE had a lower expression (0.33 ± 0.21; p < 0.05) than HCs (1 ± 0.82). For ABCG2, SVV group had a lower expression (0.17 ± 0.14; p < 0.05) than HCs (1 ± 1.82). Differences in expression of ABCC2 approached statistical significance with VC patients (2.02 ± 1.13) exhibiting higher expression than SVV patients (1.06 ± 1.11; p = 0.05). The relationships between transcript expression and patient-level data demonstrated; ABCC2 expression was different by race (1.26 ± 1.82 Caucasian versus 1.37 ± 0.86 non-Caucasian; p = 0.049) and CYP2B6 expression was different by treatment (2.07 ± 2.94 cyclophosphamide versus 0.45 ± 0.5 mycophenolate; p = 0.01). CONCLUSIONS The current study showed differential expression of drug metabolizing enzyme and transporter transcripts and contributes to the literature on transcript expression of drug transporters in leukocytes. The implications of altered local metabolism and transport in leukocytes may be important in autoimmune diseases and transplant patients where treatment is targeted to leukocytes.
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Murray B, Hawes E, Lee RA, Watson R, Roederer MW. Genes and beans: pharmacogenomics of renal transplant. Pharmacogenomics 2014; 14:783-98. [PMID: 23651025 DOI: 10.2217/pgs.13.68] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Advances in the management of patients after solid organ transplantation have led to dramatic decreases in rates of acute rejection, but long-term graft and patient survival have remained unchanged. Individualized therapy after transplant will ideally provide adequate immunosuppression while limiting the adverse effects of drug therapy that significantly impact graft survival. Therapeutic drug monitoring represents the best approximation of individualized drug therapy in transplant at this time; however, obtaining pharmacogenomic data in transplant patients has the potential to enhance our current practice. Polymorphisms of target genes that impact pharmacokinetics have been identified for most immunosuppressants, including tacrolimus, cyclosporine, mycophenolate, azathioprine and sirolimus. In the future, pre-emptive assessment of a patient's genetic profile may inform drug selection and provide information on specific doses that will improve efficacy and limit toxicity.
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Affiliation(s)
- Brian Murray
- Critical Care Clinical Specialist, UNC Hospitals & Clinics, 101 Manning Drive, CB #7600, Chapel Hill, NC 27599-7600, USA.
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18
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Stingl JC, Bartels H, Viviani R, Lehmann ML, Brockmöller J. Relevance of UDP-glucuronosyltransferase polymorphisms for drug dosing: A quantitative systematic review. Pharmacol Ther 2013; 141:92-116. [PMID: 24076267 DOI: 10.1016/j.pharmthera.2013.09.002] [Citation(s) in RCA: 125] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 09/10/2013] [Indexed: 01/01/2023]
Abstract
UDP-glucuronosyltransferases (UGT) catalyze the biotransformation of many endobiotics and xenobiotics, and are coded by polymorphic genes. However, knowledge about the effects of these polymorphisms is rarely used for the individualization of drug therapy. Here, we present a quantitative systematic review of clinical studies on the impact of UGT variants on drug metabolism to clarify the potential for genotype-adjusted therapy recommendations. Data on UGT polymorphisms and dose-related pharmacokinetic parameters in man were retrieved by a systematic search in public databases. Mean estimates of pharmacokinetic parameters were extracted for each group of carriers of UGT variants to assess their effect size. Pooled estimates and relative confidence bounds were computed with a random-effects meta-analytic approach whenever multiple studies on the same variant, ethnic group, and substrate were available. Information was retrieved on 30 polymorphic metabolic pathways involving 10 UGT enzymes. For irinotecan and mycophenolic acid a wealth of data was available for assessing the impact of genetic polymorphisms on pharmacokinetics under different dosages, between ethnicities, under comedication, and under toxicity. Evidence for effects of potential clinical relevance exists for 19 drugs, but the data are not sufficient to assess effect size with the precision required to issue dose recommendations. In conclusion, compared to other drug metabolizing enzymes much less systematic research has been conducted on the polymorphisms of UGT enzymes. However, there is evidence of the existence of large monogenetic functional polymorphisms affecting pharmacokinetics and suggesting a potential use of UGT polymorphisms for the individualization of drug therapy.
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Affiliation(s)
- J C Stingl
- Research Division, Federal Institute for Drugs and Medical Devices, Bonn, Germany; Translational Pharmacology, University of Bonn Medical Faculty, Germany.
| | - H Bartels
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, University of Ulm, Germany
| | - R Viviani
- Department of Psychiatry and Psychotherapy III, University of Ulm, Germany
| | - M L Lehmann
- Research Division, Federal Institute for Drugs and Medical Devices, Bonn, Germany
| | - J Brockmöller
- Institute of Clinical Pharmacology, University of Göttingen, Germany
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The use of allelic imbalance to ascertain cis-regulation for human UGT2B7 in vivo. Eur J Clin Pharmacol 2013; 69:1733-5. [PMID: 23740002 DOI: 10.1007/s00228-013-1538-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Accepted: 05/21/2013] [Indexed: 10/26/2022]
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20
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Abd Rahman AN, Tett SE, Staatz CE. Clinical Pharmacokinetics and Pharmacodynamics of Mycophenolate in Patients with Autoimmune Disease. Clin Pharmacokinet 2013; 52:303-31. [DOI: 10.1007/s40262-013-0039-8] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Zhao W, Fakhoury M, Deschênes G, Roussey G, Brochard K, Niaudet P, Tsimaratos M, André JL, Cloarec S, Cochat P, Bensman A, Azougagh S, Jacqz-Aigrain E. Population Pharmacokinetics and Pharmacogenetics of Mycophenolic Acid Following Administration of Mycophenolate Mofetil in De Novo Pediatric Renal-Transplant Patients. J Clin Pharmacol 2013; 50:1280-91. [DOI: 10.1177/0091270009357429] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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22
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Wang Z, Xiang Q, Cui Y, Zhao X, Zhou Y. The Influence of UGT2B7, UGT1A8, MDR1, ALDH, ADH, CYP3A4 and CYP3A5 Genetic Polymorphisms on the Pharmacokinetics of Silodosin in Healthy Chinese Volunteers. Drug Metab Pharmacokinet 2013; 28:239-43. [DOI: 10.2133/dmpk.dmpk-12-rg-106] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Polymorphisms of UGT1A9 and UGT2B7 influence the pharmacokinetics of mycophenolic acid after a single oral dose in healthy Chinese volunteers. Eur J Clin Pharmacol 2012; 69:843-9. [DOI: 10.1007/s00228-012-1409-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 09/04/2012] [Indexed: 11/26/2022]
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Chatzistefanidis D, Georgiou I, Kyritsis AP, Markoula S. Functional impact and prevalence of polymorphisms involved in the hepatic glucuronidation of valproic acid. Pharmacogenomics 2012; 13:1055-71. [DOI: 10.2217/pgs.12.78] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Metabolism of valproic acid, a widely used drug, is only partially understood. It is mainly metabolized through glucuronidation and acts as a substrate for various UDP-glucuronosyltransferases (UGTs). UGTs metabolizing valproic acid in the liver are UGT1A3, UGT1A4, UGT1A6, UGT1A9 and UGT2B7, with UGT1A6 and UGT2B7 being the most prominent. Polymorphisms in genes expressing these enzymes may have clinical consequences, regarding dosing, blood levels of the drug and adverse reactions. Not all genes are well studied and studies, where they exist, report conflicting results. Prevalence of polymorphisms and various haplotypes is also of great importance, as it may suggest different therapeutic approaches in various populations. Presented here is a review of currently known polymorphisms, their functional impact, when known, and their prevalence in different populations, highlighting the current state of understanding and areas where there is a lack of data and suggesting new perspectives for further research.
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Affiliation(s)
| | - Ioannis Georgiou
- Medical Genetics & Assisted Reproduction, Medical School, University of Ioannina, Ioannina, Greece
| | | | - Sofia Markoula
- Department of Neurology, Medical School, University of Ioannina, Ioannina, Greece
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Chu XM, Zhang LF, Wang GJ, Zhang SN, Zhou JH, Hao HP. Influence of UDP-glucuronosyltransferase polymorphisms on valproic acid pharmacokinetics in Chinese epilepsy patients. Eur J Clin Pharmacol 2012; 68:1395-401. [DOI: 10.1007/s00228-012-1277-7] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Accepted: 03/16/2012] [Indexed: 11/28/2022]
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The influence of UGT polymorphisms as biomarkers in solid organ transplantation. Clin Chim Acta 2012; 413:1318-25. [PMID: 22327003 DOI: 10.1016/j.cca.2012.01.031] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 01/20/2012] [Accepted: 01/25/2012] [Indexed: 12/18/2022]
Abstract
In solid organ transplant patients, it is important to maintain a fine balance between preventing rejection and reducing adverse effects. Several immunosuppressive agents such tacrolimus, cyclosporine, sirolimus and everolimus require therapeutic drug monitoring. The study of germline variation of the genome has opened novel opportunities to individualize therapy. Among the currently available immunosuppressive agents, cyclosporine, tacrolimus and mycophenolic acid are in vitro substrates of the UGT1A and 2B families of glucuronidation enzymes. Mycophenolic acid, either given as mycophenolate mofetil or mycophenolate sodium, is the most frequently used antiproliferative immunosuppressant. Mycophenolic acid is a prodrug which is rapidly de-esterified in the gut wall, blood, liver and tissue to the active moiety, mycophenolic acid (MPA). MPA undergoes significant hepatic metabolism to several metabolites. The 7-hydroxyglucuronide MPA is the major metabolite and is inactive. This paper reviews the current status of the genetic associations between germline UGT variants and the pharmacokinetics and pharmacodynamics of mycophenolic acid. Our conclusive assessment of the studies conducted so far is that these germline markers are not ready to be used in the clinic to individualize mycophenolic acid dosing and improve outcome. Novel approaches are required to identify new genetic determinants of outcomes in transplantation.
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Geng F, Jiao Z, Dao YJ, Qiu XY, Ding JJ, Shi XJ, Li ZD, Zhong MK. The association of the UGT1A8, SLCO1B3 and ABCC2/ABCG2 genetic polymorphisms with the pharmacokinetics of mycophenolic acid and its phenolic glucuronide metabolite in Chinese individuals. Clin Chim Acta 2011; 413:683-90. [PMID: 22227166 DOI: 10.1016/j.cca.2011.12.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 12/06/2011] [Accepted: 12/06/2011] [Indexed: 01/25/2023]
Abstract
BACKGROUND This study aimed to evaluate the effect of UGT1A8*2, SLCO1B3 T334G, ABCC2 C-24T and ABCG2 C421A polymorphisms on the pharmacokinetics (PKs) of mycophenolic acid (MPA) and its phenolic glucuronide (MPAG) in healthy Chinese volunteers and in stable renal transplant patients. METHODS The data were extracted from comparative bioavailability studies conducted in 42 healthy individuals and 37 renal transplant patients. A complete PK profile was obtained over 48 h for healthy volunteers and over 12h for the transplant patients. The MPA/MPAG plasma concentrations were measured by HPLC. The genotypes were determined using either the Taqman probe technique or direct sequencing. A multivariate analysis was used to assess the effect of the genotypes (UGT1A8*2, SLCO1B3 T334G, ABCC2 C-24T and ABCG2 C421A) and other covariates (age, weight, height, calculated creatinine clearance, serum albumin, haemoglobin and drug comedication) on the AUC(4-12) and AUC(0-12) for MPA and MPAG in the healthy volunteers and patients. RESULTS In the healthy volunteers, the dose-adjusted geometric means (GM) of the MPA AUC(4-12) in individuals with the SLCO1B3 334T allele were 30.4% lower than those values in the 334G homozygote carriers (P<0.05); in the transplant patients, the steroid dose was associated with a negative effect on the AUC of MPAG (P<0.03) and weight was associated with a negative effect on the AUC for MPA in the healthy volunteers and patients (P<0.03). No other significant effect of genotype or of the other studied variables on AUC(4-12) or AUC(0-12) of MPA/MPAG was found in the healthy volunteers or patients. CONCLUSIONS The PKs of MPA is affected by the SLCO1B3 polymorphism in healthy Chinese individuals. The absence of an effect of SLCO1B3 polymorphisms in transplant patients may be due to the co-administration of cyclosporine (CsA). Concomitant steroid dose and weight are two important covariates of the AUC of MPA and MPAG, which should be taken into account in clinical use. Further confirmatory in vivo studies are needed.
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Affiliation(s)
- Fang Geng
- Clinical Pharmacy Laboratory, Huashan Hospital, Fudan University, Shanghai, People's Republic of China
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29
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Tett SE, Saint-Marcoux F, Staatz CE, Brunet M, Vinks AA, Miura M, Marquet P, Kuypers DR, van Gelder T, Cattaneo D. Mycophenolate, clinical pharmacokinetics, formulations, and methods for assessing drug exposure. Transplant Rev (Orlando) 2011; 25:47-57. [DOI: 10.1016/j.trre.2010.06.001] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 05/26/2010] [Accepted: 06/07/2010] [Indexed: 10/18/2022]
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30
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Michelon H, König J, Durrbach A, Quteineh L, Verstuyft C, Furlan V, Ferlicot S, Letierce A, Charpentier B, Fromm MF, Becquemont L. SLCO1B1 genetic polymorphism influences mycophenolic acid tolerance in renal transplant recipients. Pharmacogenomics 2011; 11:1703-13. [PMID: 21142914 DOI: 10.2217/pgs.10.132] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
AIMS This study aimed to determine the influence of gene candidates on mycophenolic acid (MPA) response during the first year of renal transplantation. MATERIALS & METHODS A total of 218 renal transplant recipients who received MPA from the first day of transplantation at a fixed dose of 2 g/day were genotyped for ABCB1, ABCC2, UGT2B7, UGT1A9, SLCO1B1, SLCO1B3 and IMPDH1 polymorphisms. Clinical end points were MPA-related adverse drug reactions (ADRs) and acute rejection episodes during the first year post-transplantation. RESULTS After correction for multiple statistical testing, SLCO1B1 (encoding the hepatic uptake transporter OATP1B1) was the only gene associated with MPA-related ADRs, showing a 75% risk reduction in favor of a protective effect of the SLCO1B1*5 allele (p = 0.002). In vitro experiments showed that MPA metabolites MPA-phenyl-glucuronide and MPA-acyl-glucuronide are substrates of OATP1B1. Their transport was decreased in the presence of the variant transporter (OATP1B1*5). CONCLUSION These results suggest for the first time that carriers of the SLCO1B1*5 allele seem to be protected from MPA-related ADRs.
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Affiliation(s)
- Hugues Michelon
- Pharmacology Department, Univ Paris-Sud, Bicêtre University Hospital, le Kremlin, Bicêtre, France
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Sherwin CMT, Fukuda T, Brunner HI, Goebel J, Vinks AA. The evolution of population pharmacokinetic models to describe the enterohepatic recycling of mycophenolic acid in solid organ transplantation and autoimmune disease. Clin Pharmacokinet 2011; 50:1-24. [PMID: 21142265 DOI: 10.2165/11536640-000000000-00000] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
With the increasing use of mycophenolic acid (MPA) as an immunosuppressant in solid organ transplantation and in treating autoimmune diseases such as systemic lupus erythematosus, the need for strategies to optimize therapy with this agent has become increasingly apparent. This need is largely based on MPA's significant between-subject and between-occasion (within-subject) pharmacokinetic variability. While there is a strong relationship between MPA exposure and effect, the relationship between drug dose, plasma concentration and exposure (area under the concentration-time curve [AUC]) is very complex and remains to be completely defined. Population pharmacokinetic models using various approaches have been proposed over the past 10 years to further evaluate the pharmacokinetic and pharmacodynamic behaviour of MPA. These models have evolved from simple one-compartment linear iterations to complex multi-compartment versions that try to include various factors, which may influence MPA's pharmacokinetic variability, such as enterohepatic recycling and pharmacogenetic polymorphisms. There have been major advances in the understanding of the roles transport mechanisms, metabolizing and other enzymes, drug-drug interactions and pharmacogenetic polymorphisms play in MPA's pharmacokinetic variability. Given these advances, the usefulness of empirical-based models and the limitations of nonlinear mixed-effects modelling in developing mechanism-based models need to be considered and discussed. If the goal is to individualize MPA dosing, it needs to be determined whether factors which may contribute significantly to variability can be utilized in the population pharmacokinetic models. Some pharmacokinetic models developed to date show promise in being able to describe the impact of physiological processes such as enterohepatic recycling. Most studies have historically been based on retrospective data or poorly designed studies which do not take these factors into consideration. Modelling typically has been undertaken using non-controlled therapeutic drug monitoring data, which do not have the information content to support the development of complex mechanistic models. Only a few recent modelling approaches have moved away from empiricism and have included mechanisms considered important, such as enterohepatic recycling. It is recognized that well thought-out sampling schedules allow for better evaluation of the pharmacokinetic data. It is not possible to undertake complex absorption modelling with very few samples being obtained during the absorption phase (which has often been the case). It is important to utilize robust AUC monitoring which is now being propagated in the latest consensus guideline on MPA therapeutic drug monitoring. This review aims to explore the biological factors that contribute to the clinical pharmacokinetics of MPA and how these have been introduced in the development of population pharmacokinetic models. An overview of the processes involved in the enterohepatic recycling of MPA will be provided. This will summarize the components that complicate absorption and recycling to influence MPA exposure such as biotransformation, transport, bile physiology and gut flora. Already published population pharmacokinetic models will be examined, and the evolution of these models away from empirical approaches to more mechanism-based models will be discussed.
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Affiliation(s)
- Catherine M T Sherwin
- Division of Clinical Pharmacology, Cincinnati Childrens Hospital Medical Center, Cincinnati, Ohio 45229-3039, USA
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Ting LSL, Benoit-Biancamano MO, Bernard O, Riggs KW, Guillemette C, Ensom MHH. Pharmacogenetic impact of UDP-glucuronosyltransferase metabolic pathway and multidrug resistance-associated protein 2 transport pathway on mycophenolic acid in thoracic transplant recipients: an exploratory study. Pharmacotherapy 2011; 30:1097-108. [PMID: 20973683 DOI: 10.1592/phco.30.11.1097] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
STUDY OBJECTIVE To assess the contribution of polymorphisms in the uridine diphosphate glucuronosyltransferase gene (UGT) and the multidrug resistance-associated protein 2 gene (ABCC2) to mycophenolic acid (MPA) pharmacokinetics and clinical outcomes in thoracic transplant recipients. DESIGN Open-label, cross-sectional study. SETTING Transplant clinic in Vancouver, British Columbia, Canada. PATIENTS Sixty-eight thoracic (36 lung, 32 heart) transplant recipients who were receiving steady-state oral mycophenolate mofetil. MEASUREMENTS AND MAIN RESULTS Eleven blood samples were obtained from each patient over a 12-hour dosing period. Plasma concentrations of MPA (active metabolite of mycophenolate mofetil), the MPA metabolites 7-Omycophenolic acid glucuronide (MPAG) and acyl glucuronide (AcMPAG), and free MPA were measured, and dose-normalized conventional pharmacokinetic parameters were determined by noncompartmental methods. Genetic polymorphisms in UGT and ABCC2 were determined by sequencing, and their contributions to pharmacokinetic variability were investigated by using multivariate analysis. For both the lung and heart transplant groups, the UGT2B7 variant 802T (Tyr(268) or UGT2B7*2, rs7439366) and the UGT2B7 variant -138A modified AcMPAG exposure (2.5-3.7-fold and 9.3-12.3-fold higher AcMPAG area under the concentration-time curve [AUC] and AcMPAG:MPA ratio, respectively). In an exploratory analysis, occurrences of rejection, infection, anemia, and leukopenia were associated with an AcMPAG AUC greater than 50 μg·hour/ml and an AcMPAG:MPA ratio greater than 2. CONCLUSION UGT2B7 is a promising gene candidate that may influence MPA pharmacokinetics clinically; however, larger clinical pharmacogenetic studies in thoracic transplant subpopulations are warranted to corroborate the role of AcMPAG and UGT2B7 variants in optimizing mycophenolate mofetil therapy.
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Affiliation(s)
- Lillian S L Ting
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
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Dostalek M, Court MH, Hazarika S, Akhlaghi F. Diabetes mellitus reduces activity of human UDP-glucuronosyltransferase 2B7 in liver and kidney leading to decreased formation of mycophenolic acid acyl-glucuronide metabolite. Drug Metab Dispos 2010; 39:448-55. [PMID: 21123165 DOI: 10.1124/dmd.110.036608] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Mycophenolic acid (MPA) is an immunosuppressive agent commonly used after organ transplantation. Altered concentrations of MPA metabolites have been reported in diabetic kidney transplant recipients, although the reason for this difference is unknown. We aimed to compare MPA biotransformation and UDP-glucuronosyltransferase (UGT) expression and activity between liver (n = 16) and kidney (n = 8) from diabetic and nondiabetic donors. Glucuronidation of MPA, as well as the expression and probe substrate activity of UGTs primarily responsible for MPA phenol glucuronide (MPAG) formation (UGT1A1 and UGT1A9), and MPA acyl glucuronide (AcMPAG) formation (UGT2B7), was characterized. We have found that both diabetic and nondiabetic human liver microsomes and kidney microsomes formed MPAG with similar efficiency; however, AcMPAG formation was significantly lower in diabetic samples. This finding is supported by markedly lower glucuronidation of the UGT2B7 probe zidovudine, UGT2B7 protein, and UGT2B7 mRNA in diabetic tissues. UGT genetic polymorphism did not explain this difference because UGT2B7*2 or *1c genotype were not associated with altered microsomal UGT2B7 protein levels or AcMPAG formation. Furthermore, mRNA expression and probe activities for UGT1A1 or UGT1A9, both forming MPAG but not AcMPAG, were comparable between diabetic and nondiabetic tissues, suggesting the effect may be specific to UGT2B7-mediated AcMPAG formation. These findings suggest that diabetes mellitus is associated with significantly reduced UGT2B7 mRNA expression, protein level, and enzymatic activity of human liver and kidney, explaining in part the relatively low circulating concentrations of AcMPAG in diabetic patients.
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Affiliation(s)
- Miroslav Dostalek
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, Rhode Island 02881, USA
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Influence of drug transporters and UGT polymorphisms on pharmacokinetics of phenolic glucuronide metabolite of mycophenolic acid in Japanese renal transplant recipients. Ther Drug Monit 2010; 30:559-64. [PMID: 18695635 DOI: 10.1097/ftd.0b013e3181838063] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Mycophenolic acid (MPA) is mainly glucuronized by uridine diphosphate-glucuronosyltransferases (UGTs) into the phenolic MPA glucuronide (MPAG). MPAG is excreted by transporters such as organic anion-transporting polypeptide (gene SLCO), multidrug resistance protein 2 (gene ABCC2), breast cancer resistance protein (BCRP, gene ABCG2) or P-glycoprotein (gene ABCB1). This study investigated the association of UGTs, SLCOs, ABCB1, ABCC2, and ABCG2 polymorphisms with MPAG pharmacokinetics in 80 Japanese renal transplant recipients. Eighty recipients were given repeated doses of combination immunosuppressive therapy consisting of mycophenolate mofetil and tacrolimus every 12 hours at a designated time (0900 and 2100). On day 28, after renal transplantation, plasma concentrations of MPA and MPAG were measured by high-performance liquid chromatography. There were no significant differences in the area under the plasma concentration-time curve (AUC) ratio of MPAG/MPA between UGT1A1, UGT1A6, UGT1A7, UGT1A8, and UGT1A9 I399C/T genotypes. On the other hand, the median dose-adjusted AUC0-12 of MPAG in SLCO1B1 1a/1a+1a/1b+1b+1b (n = 53) and 1a/*15 + 1b/*15+*15/*15 (n = 27) were 1549 and 1134 mg.h L g, respectively (P = 0.03004 in multivariate analysis). The median dose-adjusted AUC0-12 of MPAG in SLCO1B3 334T/T+T/G (699G/G+G/A, n = 46) and 334G/G (699A/A, n = 34) was 1191 and 1580 mg.h L g, respectively (P = 0.02792 in multivariate analysis). There were no significant differences in the dose-adjusted AUC0-12 of MPAG between the ABCB1 C3435T and ABCC2 C-24T genotypes. However, the dose-adjusted AUC0-12 of MPAG was significantly lower in recipients with ABCG2 421C/A+A/A (n = 44) than in those with C/C (n = 36) (P = 0.0295). In conclusion, our findings showed that MPAG pharmacokinetics were significantly influenced by SLCO1B1 and SLCO1B3 polymorphisms and not by UGT polymorphisms. BCRP rather than multidrug resistance protein 2 seems to be the transporter associated with biliary excretion of MPAG.
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Joy MS, Boyette T, Hu Y, Wang J, La M, Hogan SL, Stewart PW, Falk RJ, Dooley MA, Smith PC. Effects of uridine diphosphate glucuronosyltransferase 2B7 and 1A7 pharmacogenomics and patient clinical parameters on steady-state mycophenolic acid pharmacokinetics in glomerulonephritis. Eur J Clin Pharmacol 2010; 66:1119-30. [PMID: 20567810 DOI: 10.1007/s00228-010-0846-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Accepted: 05/18/2010] [Indexed: 11/28/2022]
Abstract
PURPOSE The role of pharmacogenomics, clinical and demographic parameters in pharmacokinetic predictions was evaluated in patients receiving mycophenolic acid (MPA). METHODS A cohort study design of patients with glomerulonephritis secondary to lupus nephritis and anti-neutrophil cytoplasmic antibody (ANCA) vasculitis was employed. Forty-six patients with lupus nephritis and ANCA vasculitis who were receiving MPA were recruited from the nephrology clinic. The study assessed the relative single and combined roles of genomic, clinical, and demographic characteristics on pharmacokinetic parameters using general linear models. The study focused on polymorphisms in UGT1A7, UGT2B7, and ABCB1/MDR1; all of which have limited data available concerning MPA pharmacokinetics. All patients had pharmacokinetic assessments for MPA and glucuronide metabolites (MPAG, AcMPAG). Genotyping was performed for known variants of UGTs (UGT1A9, UGT1A7, UGT2B7), and multidrug resistance protein (ABCB1/MDR1), involved in MPA disposition. Analyses included univariate and multivariate linear modeling. RESULTS In univariate analyses, UGT2B7 heterozygosity (coefficient 0.3508; R (2)=0.0873) and UGT1A7 heterozygosity (coefficient 0.3778; R (2)=0.0966) predicted increased apparent oral clearance of MPA. UGT1A7 heterozygosity (coefficient -0.4647; R (2) 0.0897) predicted lower MPA trough concentrations. In multivariate assessments, higher urinary protein excretion, lower serum creatinine, and increased weight predicted greater apparent oral clearance of MPA (p < 0.0001). White race and higher serum creatinine predicted higher MPA trough concentrations (p < 0.0001). Higher exposure to MPA was predicted by decreased urinary protein excretion and increased serum creatinine. CONCLUSIONS Clinical and demographic parameters were 2-4 times more important in MPA disposition than genotypes and explained 30-40% of the pharmacokinetic parameters.
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Affiliation(s)
- Melanie S Joy
- School of Medicine, UNC Kidney Center, University of North Carolina, Chapel Hill, NC, USA.
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UGT2B7_−161C>T Polymorphism Is Associated With Lamotrigine Concentration-to-Dose Ratio in a Multivariate Study. Ther Drug Monit 2010; 32:177-84. [DOI: 10.1097/ftd.0b013e3181ceecc6] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Barraclough KA, Lee KJ, Staatz CE. Pharmacogenetic influences on mycophenolate therapy. Pharmacogenomics 2010; 11:369-90. [PMID: 20235793 DOI: 10.2217/pgs.10.9] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Mycophenolic acid (MPA) is a cornerstone immunosuppressant therapy in solid organ transplantation. MPA is metabolized by uridine diphosphate glucuronosyltransferase to inactive 7-O-MPA-glucuronide (MPAG). At least three minor metabolites are also formed, including a pharmacologically active acyl-glucuronide. MPA and MPAG are subject to enterohepatic recirculation. Biliary excretion of MPA/MPAG involves several transporters, including organic anion transporting polypeptides and multidrug resistant protein-2 (MRP-2). MPA metabolites are also excreted via the kidney, at least in part by MRP-2. MPA exerts its immunosuppressive effect through the inhibition of inosine-5-monophosphate dehydrogenase. Several SNPs have been identified in the genes encoding for uridine diphosphate glucuronosyltransferase, organic anion transporting polypeptides, MRP-2 and inosine-5-monophosphate dehydrogenase. This article provides an extensive overview of the known effects of these SNPs on the pharmacokinetics and pharmacodynamics of MPA.
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Affiliation(s)
- Katherine A Barraclough
- Department of Nephrology, Level 2, ARTS Building, Princess Alexandra Hospital, Ipswich Road, Woolloongabba, Brisbane, Qld 4102, Australia.
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Kagaya H, Miura M, Saito M, Habuchi T, Satoh S. Correlation of IMPDH1 gene polymorphisms with subclinical acute rejection and mycophenolic acid exposure parameters on day 28 after renal transplantation. Basic Clin Pharmacol Toxicol 2010; 107:631-6. [PMID: 20136638 DOI: 10.1111/j.1742-7843.2010.00542.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The risk of acute rejection in patients with higher exposure to mycophenolic acid (MPA), the active metabolite of mycophenolate mofetil (MMF), might be due to inosine 5'-monophosphate dehydrogenase (IMPDH) polymorphisms. The correlations with subclinical acute rejection, IMPDH1 polymorphisms and MPA exposure on day 28 post-transplantation were investigated in 82 Japanese recipients. Renal transplant recipients were given combination immunosuppressive therapy consisting of tacrolimus and 1.0, 1.5 or 2.0 g/day of MMF in equally divided doses every 12 hr at designated times. There were no significant differences in the incidence of subclinical acute rejection between IMPDH1 rs2278293 or rs2278294 polymorphisms (p = 0.243 and 0.735, respectively). However, in the high MPA night-time exposure range (AUC > 60 microg x h/ml and C(0 )> or = 1.9 microg/ml), there was a significant difference in the incidence of subclinical acute rejection between IMPDH1 rs2278293 A/A, A/G and G/G genotypes (each p = 0.019), but not the IMPDH1 rs2278294 genotype. In the higher daytime MPA exposure range, patients with the IMPDH1 rs2278293 G/G genotype also tended to develop subclinical acute rejection. In patients with the IMPDH rs2278293 A/A genotype, the risk of subclinical acute rejection episode tends to be low and the administration of MMF was effective. The risk of subclinical acute rejection for recipients who cannot adapt in therapeutic drug monitoring (TDM) of MPA seems to be influenced by IMPDH1 rs2278293 polymorphism. The prospective analysis of IMPDH1 rs2278293 polymorphism as well as monitoring of MPA plasma concentration after transplantation might help to improve MMF therapy.
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Affiliation(s)
- Hideaki Kagaya
- Department of Pharmacy, Akita University Hospital, Akita, Japan
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New insights into the pharmacokinetics and pharmacodynamics of the calcineurin inhibitors and mycophenolic acid: possible consequences for therapeutic drug monitoring in solid organ transplantation. Ther Drug Monit 2010; 31:416-35. [PMID: 19536049 DOI: 10.1097/ftd.0b013e3181aa36cd] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Although therapeutic drug monitoring (TDM) of immunosuppressive drugs has been an integral part of routine clinical practice in solid organ transplantation for many years, ongoing research in the field of immunosuppressive drug metabolism, pharmacokinetics, pharmacogenetics, pharmacodynamics, and clinical TDM keeps yielding new insights that might have future clinical implications. In this review, the authors will highlight some of these new insights for the calcineurin inhibitors (CNIs) cyclosporine and tacrolimus and the antimetabolite mycophenolic acid (MPA) and will discuss the possible consequences. For CNIs, important relevant lessons for TDM can be learned from the results of 2 recently published large CNI minimization trials. Furthermore, because acute rejection and drug-related adverse events do occur despite routine application of CNI TDM, alternative approaches to better predict the dose-concentration-response relationship in the individual patient are being explored. Monitoring of CNI concentrations in lymphocytes and other tissues, determination of CNI metabolites, and CNI pharmacogenetics and pharmacodynamics are in their infancy but have the potential to become useful additions to conventional CNI TDM. Although MPA is usually administered at a fixed dose, there is a rationale for MPA TDM, and this is substantiated by the increasing knowledge of the many nongenetic and genetic factors contributing to the interindividual and intraindividual variability in MPA pharmacokinetics. However, recent, large, randomized clinical trials investigating the clinical utility of MPA TDM have reported conflicting data. Therefore, alternative pharmacokinetic (ie, MPA free fraction and metabolites) and pharmacodynamic approaches to better predict drug efficacy and toxicity are being explored. Finally, for MPA and tacrolimus, novel formulations have become available. For MPA, the differences in pharmacokinetic behavior between the old and the novel formulation will have implications for TDM, whereas for tacrolimus, this probably will not to be the case.
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Genetic polymorphisms influence mycophenolate mofetil-related adverse events in pediatric heart transplant patients. J Heart Lung Transplant 2010; 29:509-16. [PMID: 20061166 DOI: 10.1016/j.healun.2009.11.602] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Revised: 11/18/2009] [Accepted: 11/20/2009] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Mycophenolate mofetil (MMF) is an effective and commonly used immunosuppressant but has frequent adverse events. Genetic polymorphisms may contribute to variability in MMF efficacy and related complications. In this study we explore the distribution frequencies of common single nucleotide polymorphisms (SNPs) of IMPDH1, IMPDH2 and ABCC2 and investigate whether these SNPs influence MMF adverse events in 59 pediatric heart recipients. METHODS Genotypes were assessed by TaqMan analysis of: ABCC2 rs717620; IMPDH2 rs11706052; and IMPDH1 rs2288553, rs2288549, rs2278293, rs2278294 and rs2228075. Gastrointestinal (GI) intolerance was defined as diarrhea, vomiting, nausea or abdominal pain requiring dose-holding for >48 hours or MMF discontinuation. Bone marrow toxicity was evaluated using Common Terminology Criteria for Adverse Events Version 3 (CTCAE). RESULTS GI intolerance occurred in 21 patients, and 21 had bone marrow toxicity. The ABCC2 rs717620 A variant was significantly associated with GI intolerance leading to drug discontinuation (p < 0.001); the IMPDH1 rs2278294 A variant and rs2228075 A variant were also associated with greater GI intolerance (p = 0.029 and p = 0.002, respectively). The IMPDH2 rs11706052 G variant was associated with more frequent neutropenia requiring dose-holding (p = 0.046). CONCLUSIONS In this small sample of pediatric heart transplant patients receiving MMF, ABCC2, IMPDH1 and IMPDH2 SNPs were associated with MMF GI intolerance and bone marrow toxicity. Thus, genetic polymorphisms may directly influence MMF adverse events.
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Bruchet NK, Ensom MHH. Limited sampling strategies for mycophenolic acid in solid organ transplantation: a systematic review. Expert Opin Drug Metab Toxicol 2009; 5:1079-97. [PMID: 19689217 DOI: 10.1517/17425250903114182] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Mycophenolic acid (MPA) is the active metabolite of mycophenolate mofetil, a widely used immunosuppressant. Numerous studies have developed limited sampling strategies (LSSs) to predict MPA AUC in solid organ transplant recipients. OBJECTIVES To systematically review and assess quality of literature pertaining to MPA LSSs, evaluate clinical implications and provide suggestions for future research. METHODS Literature searches of MEDLINE (1966 - May 2009) and EMBASE (1980 - May 2009) for English articles in solid organ transplantation, along with manual review of article references were conducted. Included articles were categorized according to criteria adapted from levels of evidence of the US Preventative Services Task Force. RESULTS Of a total of 29 studies identified, 20 were in kidney, 4 in heart, 4 in liver and 1 in lung transplantation and 7 were in pediatrics. A total of 14 studies were deemed to be Level I evidence studies, 3 were Level II-1, 1 was Level II-2 and 11 were Level III. CONCLUSIONS Although various LSSs that are well correlated to MPA AUC while being relatively unbiased and precise to predict MPA AUC have been developed, further research is needed to determine validity of these LSSs in a variety of patient populations and to determine if these LSSs improve patient outcomes.
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Miura M, Satoh S, Kagaya H, Saito M, Inoue T, Ohkubo T, Habuchi T, Suzuki T. Effect of telmisartan, valsartan and candesartan on mycophenolate mofetil pharmacokinetics in Japanese renal transplant recipients. J Clin Pharm Ther 2009; 34:683-92. [DOI: 10.1111/j.1365-2710.2009.01053.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Zaza G, Granata S, Sallustio F, Grandaliano G, Schena FP. Pharmacogenomics: a new paradigm to personalize treatments in nephrology patients. Clin Exp Immunol 2009; 159:268-80. [PMID: 19968662 DOI: 10.1111/j.1365-2249.2009.04065.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Although notable progress has been made in the therapeutic management of patients with chronic kidney disease in both conservative and renal replacement treatments (dialysis and transplantation), the occurrence of medication-related problems (lack of efficacy, adverse drug reactions) still represents a key clinical issue. Recent evidence suggests that adverse drug reactions are major causes of death and hospital admission in Europe and the United States. The reasons for these conditions are represented by environmental/non-genetic and genetic factors responsible for the great inter-patient variability in drugs metabolism, disposition and therapeutic targets. Over the years several genetic settings have been linked, using pharmacogenetic approaches, to the effects and toxicity of many agents used in clinical nephrology. However, these strategies, analysing single gene or candidate pathways, do not represent the gold standard, being the overall pharmacological effects of medications and not typically monogenic traits. Therefore, to identify multi-genetic influence on drug response, researchers and clinicians from different fields of medicine and pharmacology have started to perform pharmacogenomic studies employing innovative whole genomic high-throughput technologies. However, to date, only few pharmacogenomics reports have been published in nephrology underlying the need to enhance the number of projects and to increase the research budget for this important research field. In the future we would expect that, applying the knowledge about an individual's inherited response to drugs, nephrologists will be able to prescribe medications based on each person's genetic make-up, to monitor carefully the efficacy/toxicity of a given drug and to modify the dosage or number of medications to obtain predefined clinical outcomes.
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Affiliation(s)
- G Zaza
- Renal, Dialysis and Transplant Unit, Department of Emergency and Transplantation, University of Bari, Bari, Italy.
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Clinical Impact of Polymorphisms of Transport Proteins and Enzymes Involved in the Metabolism of Immunosuppressive Drugs. Transplant Proc 2009; 41:1441-55. [DOI: 10.1016/j.transproceed.2009.03.024] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Fujiyama N, Miura M, Satoh S, Inoue K, Kagaya H, Saito M, Habuchi T, Suzuki T. Influence of carboxylesterase 2 genetic polymorphisms on mycophenolic acid pharmacokinetics in Japanese renal transplant recipients. Xenobiotica 2009; 39:407-14. [DOI: 10.1080/00498250902807338] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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47
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Zhang WX, Chen B, Jin Z, Yu Z, Wang X, Chen H, Mao A, Cai W. Influence of uridine diphosphate (UDP)-glucuronosyltransferases and ABCC2 genetic polymorphisms on the pharmacokinetics of mycophenolic acid and its metabolites in Chinese renal transplant recipients. Xenobiotica 2008; 38:1422-36. [DOI: 10.1080/00498250802488585] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Lévesque E, Benoit-Biancamano MO, Delage R, Couture F, Guillemette C. Pharmacokinetics of mycophenolate mofetil and its glucuronide metabolites in healthy volunteers. Pharmacogenomics 2008; 9:869-79. [DOI: 10.2217/14622416.9.7.869] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We previously reported that polymorphisms in the UGT2B7 and UGT1A9 genes are associated with significant alteration in the disposition of mycophenolic acid (MPA) in healthy volunteers. Aim: This study further evaluates the impact of genetic polymorphisms at the UGT1A1, UGT1A7 and ABCC2 loci. Methods: Genetic analyses of five UGT candidate genes and ABCC2 were completed on 47 healthy subjects who received a single dose of 1.5 g mycophenolate mofetil and completed a 12-h pharmacokinetic profile. Results: Multivariate analyses indicate that the ABCC2 -24T promoter polymorphism is associated with a 25% increase in acyl mycophenolic acid phenolic glucuronide level. Subjects with combined ABCC2 -24T and UGT1A9*3 genotypes present a 169% increased exposure to AcMPAG. Homozygosity for UGT1A7 387G/391A (129Lys/131Lys) is associated with a modest but significant 7% reduction in MPA level. When these additional genetic factors are considered in the model, the effects of previously described UGT1A9 and UGT2B7 variations remain significant. No significant effect is observed for UGT1A1*28, UGT1A7 622T/C (Trp208Arg), UGT1A9 -440TC/-331CT, UGT1A9 -118 TA9/10 and seven other ABCC2 SNPs. Conclusion: We demonstrate that MPA disposition is a multigenic process, and that additional studies are required to ascertain the relationship between UGT, ABCC2 genotypes and MPA pharmacokinetics in transplant recipients.
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Affiliation(s)
- Eric Lévesque
- Laboratory of Pharmacogenomics, Oncology & Molecular Endocrinology Research Center, CHUL Research Center and Faculty of Pharmacy, Laval University, T3–48, 2705 Boul. Laurier, Québec, G1V 4G2, Canada
- Department of Hematology and Oncology, Hôtel-Dieu de Québec Hospital, Faculty of Medicine, Laval University, Québec, Canada
| | - Marie-Odile Benoit-Biancamano
- Laboratory of Pharmacogenomics, Oncology & Molecular Endocrinology Research Center, CHUL Research Center and Faculty of Pharmacy, Laval University, T3–48, 2705 Boul. Laurier, Québec, G1V 4G2, Canada
| | - Robert Delage
- Department of Hematology, Enfant-Jésus Hospital, Faculty of Medicine, Laval University, Québec, Canada
| | - Félix Couture
- Department of Hematology and Oncology, Hôtel-Dieu de Québec Hospital, Faculty of Medicine, Laval University, Québec, Canada
| | - Chantal Guillemette
- Laboratory of Pharmacogenomics, Oncology & Molecular Endocrinology Research Center, CHUL Research Center and Faculty of Pharmacy, Laval University, T3–48, 2705 Boul. Laurier, Québec, G1V 4G2, Canada
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Cattaneo D, Baldelli S, Perico N. Pharmacogenetics of immunosuppressants: progress, pitfalls and promises. Am J Transplant 2008; 8:1374-83. [PMID: 18510642 DOI: 10.1111/j.1600-6143.2008.02263.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Most of the immunosuppressants used in organ transplantation are characterized by a narrow therapeutic index, whereby underdosing is associated with increased risk of rejection episodes and overdosing may exacerbate drug-related toxicity. Pharmacogenetics--complementary to pharmacokinetics--holds the potential to allow individualized dosing of immunosuppressive agents to optimize their therapeutic actions while minimizing adverse effects. Most of the studies have focused on polymorphisms of genes involved in drug metabolism and distribution, but as of now, only thiopurine-S-methyltransferase and cytochrome P 450 3A5 genotypes appear to have sufficiently large influence to have potentialities in guiding drug dosing. This may reflect the fact that available information from other polymorphisms derives almost exclusively from retrospective observations or from studies with important methodological biases. Active investigations aimed at identifying allelic variants of gene encoding for the pharmacologic targets are now ongoing. Recent studies have demonstrated that also donor genotype may play a significant role in immunosuppressive drug pharmacokinetics and pharmacodynamics. As one of the main future tasks, it is mandatory to develop mathematical models able to incorporate multiple gene polymorphisms with pharmacokinetic data and other critical information, providing algorithms able to individualize the best immunosuppressive therapy for each patient before transplantation.
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Affiliation(s)
- D Cattaneo
- Department of Medicine and Transplantation, Azienda Ospedaliera Ospedali Riuniti, Bergamo and Mario Negri Institute for Pharmacological Research, Bergamo, Italy.
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Pharmacogenetic effect of the UGT polymorphisms on mycophenolate is modified by calcineurin inhibitors. Eur J Clin Pharmacol 2008; 64:1047-56. [PMID: 18568343 DOI: 10.1007/s00228-008-0501-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2008] [Accepted: 04/22/2008] [Indexed: 12/15/2022]
Abstract
BACKGROUND Mycophenolic acid (MPA) is glucuronidated primarily by uridine diphosphate glucuronosyltransferase enzymes (UGT) 1A9 and 1A8. These enzymes are highly polymorphic resulting in low activity and high expression phenotypes. We hypothesized that polymorphisms of UGT1A9 and 1A8 may alter MPA pharmacokinetics in kidney transplantation. METHODS One hundred seventeen kidney (n = 93), pancreas (n = 11), or simultaneous kidney and pancreas (SPK) (n = 13) transplant recipients were studied for the effect of UGT1A9 and UGT1A8 polymorphisms on MPA dose-corrected trough concentrations. Individuals were genotyped for UGT1A8 and UGT1A9 polymorphisms (1A8*2, 1A8*3, 1A9*3, 1A9-275 and 1A9-2152). Linear regression was used to estimate the effect of UGT polymorphisms on the individual's mean MPA dose-corrected trough concentration with and without stratification by calcineurin inhibitor. A multiple linear regression analysis was performed to assess the dependence between the average MPA dose-corrected trough concentration and age, gender, UGT genotype (1A8*2, 1A8*3, 1A9*3, 1A9-275, 1A9-2152), serum albumin, hemoglobin (Hgb), hematocrit (HCT), liver transaminases (AST, ALT), serum creatinine, and bilirubin. RESULTS Mycophenolic acid dose-corrected trough concentrations were 60% higher in subjects heterozygous or homozygous for UGT1A8*2 than in those with the wild type (p = 0.02); however, this effect was dependent on concomitant calcineurin inhibitor. When subjects were stratified by calcineurin inhibitor status, the UGT1A8*2 effect was only apparent in the tacrolimus group (p < 0.01). Mycophenolic acid dose-corrected trough concentrations were 70% lower in carriers of the UGT1A9 -275T>A/-2152 C>T polymorphism who received cyclosporine (p < 0.01). There was no effect of the UGT1A9 -275T>A/-2152C>T polymorphism in the tacrolimus group. CONCLUSIONS The effect of UGT1A8 and UGT1A9 variants on MPA metabolism appears to be modified by concomitant calcineurin inhibitor therapy. Confirmatory in vivo and in vitro studies are needed.
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