1
|
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 2024:1-30. [PMID: 38884938 DOI: 10.1080/14622416.2024.2344430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [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.
Collapse
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
| |
Collapse
|
2
|
Babayeva M, Loewy ZG. Cannabis Pharmacogenomics: A Path to Personalized Medicine. Curr Issues Mol Biol 2023; 45:3479-3514. [PMID: 37185752 PMCID: PMC10137111 DOI: 10.3390/cimb45040228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 04/05/2023] [Accepted: 04/12/2023] [Indexed: 05/17/2023] Open
Abstract
Cannabis and related compounds have created significant research interest as a promising therapy in many disorders. However, the individual therapeutic effects of cannabinoids and the incidence of side effects are still difficult to determine. Pharmacogenomics may provide the answers to many questions and concerns regarding the cannabis/cannabinoid treatment and help us to understand the variability in individual responses and associated risks. Pharmacogenomics research has made meaningful progress in identifying genetic variations that play a critical role in interpatient variability in response to cannabis. This review classifies the current knowledge of pharmacogenomics associated with medical marijuana and related compounds and can assist in improving the outcomes of cannabinoid therapy and to minimize the adverse effects of cannabis use. Specific examples of pharmacogenomics informing pharmacotherapy as a path to personalized medicine are discussed.
Collapse
Affiliation(s)
- Mariana Babayeva
- Department of Biomedical and Pharmaceutical Sciences, Touro College of Pharmacy, New York, NY 10027, USA
| | - Zvi G Loewy
- Department of Biomedical and Pharmaceutical Sciences, Touro College of Pharmacy, New York, NY 10027, USA
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, NY 10595, USA
| |
Collapse
|
3
|
Pharmacogenetic Aspects of Drug Metabolizing Enzymes and Transporters in Pediatric Medicine: Study Progress, Clinical Practice and Future Perspectives. Paediatr Drugs 2023; 25:301-319. [PMID: 36707496 DOI: 10.1007/s40272-023-00560-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/09/2023] [Indexed: 01/28/2023]
Abstract
As the activity of certain drug metabolizing enzymes or transporter proteins can vary with age, the effect of ontogenetic and genetic variation on the activity of these enzymes is critical for the accurate prediction of treatment outcomes and toxicity in children. This makes pharmacogenetic research in pediatrics particularly important and urgently needed, but also challenging. This review summarizes pharmacogenetic studies on the effects of genetic polymorphisms on pharmacokinetic parameters and clinical outcomes in pediatric populations for certain drugs, which are commonly prescribed by clinicians across multiple therapeutic areas in a general hospital, organized from those with the most to the least pediatric evidence among each drug category. We also further discuss the research status of the gene-guided dosing regimens and clinical implementation of pediatric pharmacogenetics. More and more drug-gene interactions are demonstrated to have clinical validity for children, and pharmacogenomics in pediatrics have shown evidence-based benefits to enhance the efficacy and precision of existing drug dosing regimens in several therapeutic areas. However, the most important limitation to the implementation is the lack of high-quality, rigorous pediatric prospective clinical studies, so adequately powered interventional clinical trials that support incorporation of pharmacogenetics into the care of children are still needed.
Collapse
|
4
|
Islam F, Islam MR, Nafady MH, Faysal M, Khan SL, Zehravi M, Emran TB, Rahman MH. Pharmacogenomics of immunosuppressants. Pharmacogenomics 2023:323-344. [DOI: 10.1016/b978-0-443-15336-5.00003-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023] Open
|
5
|
Mycophenolate mofetil use is associated with reduced incidence of food allergy in liver transplanted children. J Pediatr Gastroenterol Nutr 2022; 75:138-144. [PMID: 35666879 DOI: 10.1097/mpg.0000000000003509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
OBJECTIVES The incidence of food allergy in children following liver transplantation is high and the pathogenesis is still not known. We aimed to identify risk factors for development of food allergies in liver transplant children. METHODS 107 children and adolescents who underwent liver transplantation from 1999 to 2019 were included. Data were retrospectively collected from medical records included total and specific IgE, eosinophil cationic protein and eosinophil count 12 months after transplantation and at yearly follow up (median follow-up). RESULTS 24/107 (22%) patients reported clinical food reactions. Median time from transplantation to debut of food allergy was 1.6 (IQR 0.6-3.3) years. Mycophenolate mofetil (MMF) was discontinued in 24/78 patients (31%) due to side effects. Children treated with MMF in addition to tacrolimus one year after transplantation reported less food allergy (12.5% vs. 37.8%, p=0.003) and sensitization to food allergens one year after transplantation (8.9% vs. 17.8%, p=0.02) than those not receiving MMF. Tacrolimus trough levels did not differ between the patients treated with MMF and those who were not. Treatment with MMF two years after transplantation was associated with less food allergy (p=0.001) and food sensitization (p=0.002), also when adjusted for age at transplantation (p=0.006 and p=0.03, respectively) or for use of basilixmab (p=0.015 and p=0.018, respectively). Basiliximab was also associated with less food allergy. CONCLUSIONS Use of MMF one and two years after transplantation was associated with less food allergy and sensitization against food allergens. The effect of MMF was not due to reduced trough levels of of tacrolimus. An infographic is available for this article at: https://links.lww.com/MPG/C821.
Collapse
|
6
|
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.
Collapse
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
| |
Collapse
|
7
|
Job KM, Roberts JK, Enioutina EY, IIIamola SM, Kumar SS, Rashid J, Ward RM, Fukuda T, Sherbotie J, Sherwin CM. Treatment optimization of maintenance immunosuppressive agents in pediatric renal transplant recipients. Expert Opin Drug Metab Toxicol 2021; 17:747-765. [PMID: 34121566 PMCID: PMC10726690 DOI: 10.1080/17425255.2021.1943356] [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: 11/09/2020] [Accepted: 06/11/2021] [Indexed: 10/21/2022]
Abstract
Introduction: Graft survival in pediatric kidney transplant patients has increased significantly within the last three decades, correlating with the discovery and utilization of new immunosuppressants as well as improvements in patient care. Despite these developments in graft survival for patients, there is still improvement needed, particularly in long-term care in pediatric patients receiving grafts from deceased donor patients. Maintenance immunosuppressive therapies have narrow therapeutic indices and are associated with high inter-individual and intra-individual variability.Areas covered: In this review, we examine the impact of pharmacokinetic variability on renal transplantation and its association with age, genetic polymorphisms, drug-drug interactions, drug-disease interactions, renal insufficiency, route of administration, and branded versus generic drug formulation. Pharmacodynamics are outlined in terms of the mechanism of action for each immunosuppressant, potential adverse effects, and the utility of pharmacodynamic biomarkers.Expert opinion: Acquiring abetter quantitative understanding of immunosuppressant pharmacokinetics and pharmacodynamic components should help clinicians implement treatment regimens to maintain the balance between therapeutic efficacy and drug-related toxicity.
Collapse
Affiliation(s)
- Kathleen M Job
- Division of Clinical Pharmacology, Department of Pediatrics, University of Utah, Salt Lake City, UT, USA
| | - Jessica K Roberts
- Division of Clinical Pharmacology, Department of Pediatrics, University of Utah, Salt Lake City, UT, USA
| | - Elena Y Enioutina
- Division of Clinical Pharmacology, Department of Pediatrics, University of Utah, Salt Lake City, UT, USA
| | - Sílvia M IIIamola
- Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, MN, USA
| | - Shaun S Kumar
- Division of Clinical Pharmacology, Department of Pediatrics, University of Utah, Salt Lake City, UT, USA
| | - Jahidur Rashid
- Division of Clinical Pharmacology, Department of Pediatrics, University of Utah, Salt Lake City, UT, USA
| | - Robert M Ward
- Division of Clinical Pharmacology, Department of Pediatrics, University of Utah, Salt Lake City, UT, USA
- Department of Pediatrics, School of Medicine, University of Utah, Salt Lake City, UT, USA
| | - Tsuyoshi Fukuda
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Joseph Sherbotie
- Department of Pediatrics, School of Medicine, University of Utah, Salt Lake City, UT, USA
| | - Catherine M Sherwin
- Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, MN, USA
- Department of Pediatrics, Boonshoft School of Medicine, Dayton Children’s Hospital, Wright State University, Dayton, OH, USA
- Department of Pharmacotherapy, College of Pharmacy, University of Utah, Salt Lake City, UT, USA
| |
Collapse
|
8
|
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: 87] [Impact Index Per Article: 29.0] [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.
Collapse
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
| |
Collapse
|
9
|
Salvadori M, Tsalouchos A. Pharmacogenetics of immunosuppressant drugs: A new aspect for individualized therapy. World J Transplant 2020; 10:90-103. [PMID: 32864355 PMCID: PMC7428791 DOI: 10.5500/wjt.v10.i5.90] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 03/26/2020] [Accepted: 04/23/2020] [Indexed: 02/06/2023] Open
Abstract
In recent years, pharmacogenetics has emerged as an important tool for choosing the right immunosuppressant drug and its appropriate dose. Indeed, pharmacogenetics may exert its action on immunosuppressant drugs at three levels. Pharmacogenetics identifies and studies the genes involved in encoding the proteins involved in drug pharmacokinetics and in encoding the enzymes involved in drug degradation. Pharmacogenetics is also relevant in encoding the enzymes and proteins involved in codifying the transmembrane proteins involved in transmembrane passage favoring the absorption and intracellular action of several immunosuppressants. Pharmacogenetics concern the variability of genes encoding the proteins involved as immunosuppressant triggers in the pharmacodynamic pathways. Of course, not all genes have been discovered and studied, but some of them have been clearly examined and their relevance together with other factors such as age and race has been defined. Other genes on the basis of relevant studies have been proposed as good candidates for future studies. Unfortunately, to date, clear conclusions may be drawn only for those drugs that are metabolized by CYP3A5 and its genotyping before kidney, heart and lung transplantation is recommended. The conclusions of the studies on the recommended candidate genes, together with the development of omics techniques could in the future allow us to choose the right dose of the right immunosuppressant for the right patient.
Collapse
Affiliation(s)
- Maurizio Salvadori
- Department of Renal Transplantation, Careggi University Hospital, Florence 50139, Italy
| | - Aris Tsalouchos
- Nephrology and Dialysis Unit, Saints Cosmas and Damian Hospital, Pescia 51017, Italy
| |
Collapse
|
10
|
Yanik MV, Seifert ME, Locke JE, Hauptfeld-Dolejsek V, Crowley MR, Cutter GR, Mannon RB, Feig DI, Limdi NA. CYP3A5 genotype affects time to therapeutic tacrolimus level in pediatric kidney transplant recipients. Pediatr Transplant 2019; 23:e13494. [PMID: 31124575 PMCID: PMC8009482 DOI: 10.1111/petr.13494] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 03/30/2019] [Accepted: 04/23/2019] [Indexed: 12/12/2022]
Abstract
BACKGROUND Optimal management of immunosuppression in kidney transplantation requires a delicate balance of efficacy and toxicity. Tacrolimus (TAC) dose requirements are significantly impacted by genetic variation in CYP3A5 polymorphisms, however the impact that genotype has on clinical outcomes in the pediatric kidney transplant population remains unclear. METHODS We evaluated a retrospective cohort of 98 pediatric kidney transplant recipients. The primary exposure was CYP3A5 genotype, which classified each recipient into the expresser (at least one CYP3A5*1 allele) or non-expresser group (only CYP3A5*3 alleles). The primary outcome was time to achieve a steady therapeutic TAC concentration. Secondary outcomes include incidence of early allograft rejection and calcineurin inhibitor (CNI) nephrotoxicity during the first year post-transplant. RESULTS The study cohort included 55 (56%) expressers and 43 (44%) non-expressers of the CYP3A5*1 allele. Expressers had a significantly longer time to achieve a steady therapeutic TAC concentration than non-expressers (log rank, P = 0.03). Expressers had a trend for higher incidence of early allograft rejection (29.1% vs 16.3%, log rank, P = 0.16). Early biopsy-proven CNI nephrotoxicity was seen in 60% of recipients, with no differences in the rate between expressers and non-expressers. CONCLUSIONS Pediatric kidney transplant recipients with the CYP3A5*1 allele (expressers) take a longer time to achieve therapeutic TAC levels than those with the CYP3A5*3 allele (non-expressers). However, we observed no significant differences in acute rejection or CNI nephrotoxicity based on CYP3A5 genotype. Thus CYP3A5 genotype was not observed to have an immediate impact on early transplant outcomes.
Collapse
Affiliation(s)
- Megan V. Yanik
- Division of Nephrology, Department of Pediatrics, University of Alabama at Birmingham, Birmingham, Alabama
| | - Michael E. Seifert
- Division of Nephrology, Department of Pediatrics, University of Alabama at Birmingham, Birmingham, Alabama
| | - Jayme E. Locke
- Department of Surgery, Division of Transplantation, University of Alabama at Birmingham, Birmingham, Alabama
| | - Vera Hauptfeld-Dolejsek
- Department of Surgery, Division of Transplantation, University of Alabama at Birmingham, Birmingham, Alabama
| | - Michael R. Crowley
- Heflin Center for Genomic Science, University of Alabama at Birmingham, Birmingham, Alabama
| | - Gary R. Cutter
- Department of Biostatistics, University of Alabama at Birmingham, Birmingham, Alabama
| | - Roslyn B. Mannon
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Daniel I. Feig
- Division of Nephrology, Department of Pediatrics, University of Alabama at Birmingham, Birmingham, Alabama
| | - Nita A. Limdi
- Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama
| |
Collapse
|
11
|
Varnell CD, Fukuda T, Kirby CL, Martin LJ, Warshaw BL, Patel HP, Chand DH, Barletta GM, Van Why SK, VanDeVoorde RG, Weaver DJ, Wilson A, Verghese PS, Vinks AA, Greenbaum LA, Goebel J, Hooper DK. Mycophenolate mofetil-related leukopenia in children and young adults following kidney transplantation: Influence of genes and drugs. Pediatr Transplant 2017; 21:10.1111/petr.13033. [PMID: 28869324 PMCID: PMC5905326 DOI: 10.1111/petr.13033] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/27/2017] [Indexed: 12/31/2022]
Abstract
MMF is commonly prescribed following kidney transplantation, yet its use is complicated by leukopenia. Understanding the genetics mediating this risk will help clinicians administer MMF safely. We evaluated 284 patients under 21 years of age for incidence and time course of MMF-related leukopenia and performed a candidate gene association study comparing the frequency of 26 SNPs between cases with MMF-related leukopenia and controls. We matched cases by induction, steroid duration, race, center, and age. We also evaluated the impact of induction and SNPs on time to leukopenia in all cases. Sixty-eight (24%) patients had MMF-related leukopenia, of which 59 consented for genotyping and 38 were matched with controls. Among matched pairs, no SNPs were associated with leukopenia. With non-depleting induction, UGT2B7-900A>G (rs7438135) was associated with increased risk of MMF-related leukopenia (P = .038). Time to leukopenia did not differ between patients by induction agent, but 2 SNPs (rs2228075, rs2278294) in IMPDH1 were associated with increased time to leukopenia. MMF-related leukopenia is common after transplantation. UGT2B7 may influence leukopenia risk especially in patients without lymphocyte-depleting induction. IMPDH1 may influence time course of leukopenia after transplant.
Collapse
Affiliation(s)
- Charles D. Varnell
- Division of Nephrology and Hypertension, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
| | - Tsuyoshi Fukuda
- Division of Clinical Pharmacology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Cassie L. Kirby
- Division of Nephrology and Hypertension, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
| | - Lisa J. Martin
- Division of Human Genetics, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
| | - Barry L. Warshaw
- Division of Nephrology, Emory University School of Medicine and Children’s Healthcare of Atlanta, Atlanta, GA, USA
| | - Hiren P. Patel
- Division of Nephrology, Nationwide Children’s Hospital, Columbus, OH, USA
| | - Deepa H. Chand
- Division of Nephrology, University of Illinois College of Medicine, Peoria, IL, USA,Abbvie, North Chicago, IL, USA
| | | | - Scott K. Van Why
- Division of Pediatric Nephrology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Rene G. VanDeVoorde
- Division of Nephrology, Monroe Carell Jr. Children’s Hospital, Nashville, TN, USA
| | - Donald J. Weaver
- Division of Nephrology, Levine Children’s Hospital, Charlotte, NC, USA
| | - Amy Wilson
- Division of Nephrology, Riley Hospital for Children, Indianapolis, IN, USA
| | - Priya S. Verghese
- Division of Pediatric Nephrology, University of Minnesota Masonic Children’s Hospital, Minneapolis, MN, USA
| | - Alexander A. Vinks
- Division of Clinical Pharmacology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Larry A. Greenbaum
- Division of Nephrology, Emory University School of Medicine and Children’s Healthcare of Atlanta, Atlanta, GA, USA
| | - Jens Goebel
- Division of Nephrology, Children’s Hospital Colorado, Aurora, CO, USA
| | - David K. Hooper
- Division of Nephrology and Hypertension, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA,James M. Anderson Center for Health Systems Excellence, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
| |
Collapse
|
12
|
Relationship between UGT1A9 gene polymorphisms, efficacy, and safety of propofol in induced abortions amongst Chinese population: a population-based study. Biosci Rep 2017; 37:BSR20170722. [PMID: 28899924 PMCID: PMC5653915 DOI: 10.1042/bsr20170722] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 09/07/2017] [Accepted: 09/08/2017] [Indexed: 11/17/2022] Open
Abstract
The present study aimed to investigate the influence of UGT1A9 gene polymorphisms on the efficacy of propofol in patients undergoing the painless induced abortion method. A total of 156 women seeking voluntary pregnancy termination procedures were selected for the study, and subsequently underwent painless induced abortions, following anesthesia by means of propofol administration. PCR-restriction fragment length polymorphism (PCR-RFLP) was performed to detect the polymorphisms of UGT1A9 gene at -440C/T, -1818C/T, and -1887T/G loci. The time, effect-site concentration, and bispectral index (BIS) for the Observer's Assessment of Alertness/Sedation (OAA/S) (up to 4 points) were observed and recorded in patients following discontinuation of propofol. The time and effect-site concentration for BIS reaching 80 in patients following the discontinuation of propofol were observed and recorded. Postoperative observations of adverse reactions, such as nausea, vomiting, and respiratory depression were all made record of. In comparison with patients with UGT1A9 -440C/T CT and TT, those with UGT1A9 -440C/T CC displayed shorter durations of OAA/S by up to 4 points, shorter BIS times reaching 80, as well as higher corresponding effect-site concentrations. No significant differences were detected in the patients with -440C/T, -1818T/C, and -1887T/G in incidence of nausea, vomiting, and respiratory depression. The findings of the study highlighted correlation between UGT1A9 -440C/T gene polymorphisms and positive propofol efficacy in patients undergoing painless induced pregnancy termination procedures.
Collapse
|
13
|
Scotcher D, Billington S, Brown J, Jones CR, Brown CDA, Rostami-Hodjegan A, Galetin A. Microsomal and Cytosolic Scaling Factors in Dog and Human Kidney Cortex and Application for In Vitro-In Vivo Extrapolation of Renal Metabolic Clearance. Drug Metab Dispos 2017; 45:556-568. [PMID: 28270564 PMCID: PMC5399648 DOI: 10.1124/dmd.117.075242] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 02/27/2017] [Indexed: 12/17/2022] Open
Abstract
In vitro-in vivo extrapolation of drug metabolism data obtained in enriched preparations of subcellular fractions rely on robust estimates of physiologically relevant scaling factors for the prediction of clearance in vivo. The purpose of the current study was to measure the microsomal and cytosolic protein per gram of kidney (MPPGK and CPPGK) in dog and human kidney cortex using appropriate protein recovery marker and evaluate functional activity of human cortex microsomes. Cytochrome P450 (CYP) content and glucose-6-phosphatase (G6Pase) activity were used as microsomal protein markers, whereas glutathione-S-transferase activity was a cytosolic marker. Functional activity of human microsomal samples was assessed by measuring mycophenolic acid glucuronidation. MPPGK was 33.9 and 44.0 mg/g in dog kidney cortex, and 41.1 and 63.6 mg/g in dog liver (n = 17), using P450 content and G6Pase activity, respectively. No trends were noted between kidney, liver, and intestinal scalars from the same animals. Species differences were evident, as human MPPGK and CPPGK were 26.2 and 53.3 mg/g in kidney cortex (n = 38), respectively. MPPGK was 2-fold greater than the commonly used in vitro-in vivo extrapolation scalar; this difference was attributed mainly to tissue source (mixed kidney regions versus cortex). Robust human MPPGK and CPPGK scalars were measured for the first time. The work emphasized the importance of regional differences (cortex versus whole kidney–specific MPPGK, tissue weight, and blood flow) and a need to account for these to improve assessment of renal metabolic clearance and its extrapolation to in vivo.
Collapse
Affiliation(s)
- Daniel Scotcher
- Centre for Applied Pharmacokinetic Research, University of Manchester, Manchester (D.S., A.R.-H., A.G.); Newcastle University, Newcastle (S.B., C.D.A.B.); Biobank, Central Manchester University Hospitals NHS Foundation Trust, Manchester (J.B.); DMPK, Oncology iMed, AstraZeneca R&D, Alderley Park, Macclesfield (C.R.J.); and Simcyp Limited (a Certara Company), Blades Enterprise Centre, Sheffield (A.R.-H.), United Kingdom
| | - Sarah Billington
- Centre for Applied Pharmacokinetic Research, University of Manchester, Manchester (D.S., A.R.-H., A.G.); Newcastle University, Newcastle (S.B., C.D.A.B.); Biobank, Central Manchester University Hospitals NHS Foundation Trust, Manchester (J.B.); DMPK, Oncology iMed, AstraZeneca R&D, Alderley Park, Macclesfield (C.R.J.); and Simcyp Limited (a Certara Company), Blades Enterprise Centre, Sheffield (A.R.-H.), United Kingdom
| | - Jay Brown
- Centre for Applied Pharmacokinetic Research, University of Manchester, Manchester (D.S., A.R.-H., A.G.); Newcastle University, Newcastle (S.B., C.D.A.B.); Biobank, Central Manchester University Hospitals NHS Foundation Trust, Manchester (J.B.); DMPK, Oncology iMed, AstraZeneca R&D, Alderley Park, Macclesfield (C.R.J.); and Simcyp Limited (a Certara Company), Blades Enterprise Centre, Sheffield (A.R.-H.), United Kingdom
| | - Christopher R Jones
- Centre for Applied Pharmacokinetic Research, University of Manchester, Manchester (D.S., A.R.-H., A.G.); Newcastle University, Newcastle (S.B., C.D.A.B.); Biobank, Central Manchester University Hospitals NHS Foundation Trust, Manchester (J.B.); DMPK, Oncology iMed, AstraZeneca R&D, Alderley Park, Macclesfield (C.R.J.); and Simcyp Limited (a Certara Company), Blades Enterprise Centre, Sheffield (A.R.-H.), United Kingdom
| | - Colin D A Brown
- Centre for Applied Pharmacokinetic Research, University of Manchester, Manchester (D.S., A.R.-H., A.G.); Newcastle University, Newcastle (S.B., C.D.A.B.); Biobank, Central Manchester University Hospitals NHS Foundation Trust, Manchester (J.B.); DMPK, Oncology iMed, AstraZeneca R&D, Alderley Park, Macclesfield (C.R.J.); and Simcyp Limited (a Certara Company), Blades Enterprise Centre, Sheffield (A.R.-H.), United Kingdom
| | - Amin Rostami-Hodjegan
- Centre for Applied Pharmacokinetic Research, University of Manchester, Manchester (D.S., A.R.-H., A.G.); Newcastle University, Newcastle (S.B., C.D.A.B.); Biobank, Central Manchester University Hospitals NHS Foundation Trust, Manchester (J.B.); DMPK, Oncology iMed, AstraZeneca R&D, Alderley Park, Macclesfield (C.R.J.); and Simcyp Limited (a Certara Company), Blades Enterprise Centre, Sheffield (A.R.-H.), United Kingdom
| | - Aleksandra Galetin
- Centre for Applied Pharmacokinetic Research, University of Manchester, Manchester (D.S., A.R.-H., A.G.); Newcastle University, Newcastle (S.B., C.D.A.B.); Biobank, Central Manchester University Hospitals NHS Foundation Trust, Manchester (J.B.); DMPK, Oncology iMed, AstraZeneca R&D, Alderley Park, Macclesfield (C.R.J.); and Simcyp Limited (a Certara Company), Blades Enterprise Centre, Sheffield (A.R.-H.), United Kingdom
| |
Collapse
|
14
|
Hahn A, Fukuda T, Hahn D, Mizuno T, Frenck RW, Vinks AA. Pharmacokinetics and pharmacogenomics of β-lactam-induced neutropenia. Pharmacogenomics 2016; 17:547-59. [PMID: 27045542 DOI: 10.2217/pgs-2015-0008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
AIM Determine if individuals with β-lactam induced neutropenia have polymorphisms that impair function of MRP4 or OAT1/OAT3. METHODS Subjects with β-lactam induced neutropenia were compared to controls for the presence of MRP4 and OAT1/OAT3 polymorphisms, estimated plasma trough concentrations and area under the curve. RESULTS Subjects with a homozygous polymorphism at MRP4 3348 A to G were 5.3 times more likely to develop neutropenia (p = 0.171). No statistical differences were noted in pharmacokinetic parameters. Contingency analysis of children greater than 5 years of age showed neutropenia in subjects who were homozygous wild type at MRP4 3348 A to G was significantly associated with standard or high dosing (p = 0.03). CONCLUSION MRP4 3348 A to G should be further studied for potential contribution to the development of β-lactam induced neutropenia.
Collapse
Affiliation(s)
- Andrea Hahn
- Division of Infectious Disease, Children's National Medical Center, Washington, DC 200102, USA.,Department of Pediatrics, George Washington University School of Medicine, Washington, DC 200523, USA
| | - Tsuyoshi Fukuda
- Division of Clinical Pharmacology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 452294, USA.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 452215, USA
| | - David Hahn
- Division of Clinical Pharmacology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 452294, USA
| | - Tomoyuki Mizuno
- Division of Clinical Pharmacology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 452294, USA
| | - Robert W Frenck
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 452215, USA.,Division of Infectious Disease, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Alexander A Vinks
- Division of Clinical Pharmacology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 452294, USA.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 452215, USA
| |
Collapse
|
15
|
Pharmacogenetic Biomarkers Predictive of the Pharmacokinetics and Pharmacodynamics of Immunosuppressive Drugs. Ther Drug Monit 2016; 38 Suppl 1:S57-69. [DOI: 10.1097/ftd.0000000000000255] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
|
16
|
Dong M, Fukuda T, Cox S, de Vries MT, Hooper DK, Goebel J, Vinks AA. Population pharmacokinetic-pharmacodynamic modelling of mycophenolic acid in paediatric renal transplant recipients in the early post-transplant period. Br J Clin Pharmacol 2015; 78:1102-12. [PMID: 24837828 DOI: 10.1111/bcp.12426] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 05/12/2014] [Indexed: 11/30/2022] Open
Abstract
AIM The purpose of this study was to develop a population pharmacokinetic and pharmacodynamic (PK-PD) model for mycophenolic acid (MPA) in paediatric renal transplant recipients in the early post-transplant period. METHODS A total of 214 MPA plasma concentrations-time data points from 24 patients were available for PK model development. In 17 out of a total of 24 patients, inosine monophosphate dehydrogenase (IMPDH) enzyme activity measurements (n = 97) in peripheral blood mononuclear cells were available for PK-PD modelling. The PK-PD model was developed using non-linear mixed effects modelling sequentially by 1) developing a population PK model and 2) incorporating IMPDH activity into a PK-PD model using post hoc Bayesian PK parameter estimates. Covariate analysis included patient demographics, co-medication and clinical laboratory data. Non-parametric bootstrapping and prediction-corrected visual predictive checks were performed to evaluate the final models. RESULTS A two compartment model with a transit compartment absorption best described MPA PK. A non-linear relationship between dose and MPA exposure was observed and was described by a power function in the model. The final population PK parameter estimates (and their 95% confidence intervals) were CL/F, 22 (14.8, 25.2) l h(-1) 70 kg(-1) ; Vc /F, 45.4 (29.6, 55.6) l; Vp /F, 411 (152.6, 1472.6)l; Q/F, 22.4 (16.0, 32.5) l h(-1) ; Ka , 2.5 (1.45, 4.93) h(-1) . Covariate analysis in the PK study identified body weight to be significantly correlated with CL/F. A simplified inhibitory Emax model adequately described the relationship between MPA concentration and IMPDH activity. The final population PK-PD parameter estimates (and their 95% confidence intervals) were: E0 , 3.45 (2.61, 4.56) nmol h(-1) mg(-1) protein and EC50 , 1.73 (1.16, 3.01) mg l(-1) . Emax was fixed to 0. There were two African-American patients in our study cohorts and both had low IMPDH baseline activities (E0 ) compared with Caucasian patients (mean value 2.13 mg l(-1) vs. 3.86 mg l(-1) ). CONCLUSION An integrated population PK-PD model of MPA has been developed in paediatric renal transplant recipients. The current model provides information that will facilitate future studies and may be implemented in a Bayesian algorithm to allow a PK-PD guided therapeutic drug monitoring strategy.
Collapse
Affiliation(s)
- Min Dong
- Division of Clinical Pharmacology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | | | | | | | | | | | | |
Collapse
|
17
|
Personalization of the immunosuppressive treatment in renal transplant recipients: the great challenge in "omics" medicine. Int J Mol Sci 2015; 16:4281-305. [PMID: 25690039 PMCID: PMC4346957 DOI: 10.3390/ijms16024281] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 02/04/2015] [Accepted: 02/09/2015] [Indexed: 12/25/2022] Open
Abstract
Renal transplantation represents the most favorable treatment for patients with advanced renal failure and it is followed, in most cases, by a significant enhancement in patients’ quality of life. Significant improvements in one-year renal allograft and patients’ survival rates have been achieved over the last 10 years primarily as a result of newer immunosuppressive regimens. Despite these notable achievements in the short-term outcome, long-term graft function and survival rates remain less than optimal. Death with a functioning graft and chronic allograft dysfunction result in an annual rate of 3%–5%. In this context, drug toxicity and long-term chronic adverse effects of immunosuppressive medications have a pivotal role. Unfortunately, at the moment, except for the evaluation of trough drug levels, no clinically useful tools are available to correctly manage immunosuppressive therapy. The proper use of these drugs could potentiate therapeutic effects minimizing adverse drug reactions. For this purpose, in the future, “omics” techniques could represent powerful tools that may be employed in clinical practice to routinely aid the personalization of drug treatment according to each patient’s genetic makeup. However, it is unquestionable that additional studies and technological advances are needed to standardize and simplify these methodologies.
Collapse
|
18
|
Abstract
The transplantation literature includes numerous papers that report associations between polymorphisms in genes encoding metabolizing enzymes and drug transporters, and pharmacokinetic data on immunosuppressive drugs. Most of these studies are retrospective in design, and although a substantial number report significant associations, pharmacogenetic tests are hardly used in clinical practice. One of the reasons for this poor implementation is the current lack of evidence of improved clinical outcome with pharmacogenetic testing. Furthermore, with efficient therapeutic drug monitoring it is possible to rapidly correct for the effect of genotypic deviations on pharmacokinetics, thereby decreasing the utility of genotype-based dosing. The future of pharmacogenetics will be in treatment models in which patient characteristics are combined with data on polymorphisms in multiple genes. These models should focus on pharmacodynamic parameters, variations in the expression of drug transporter proteins, and predictors of toxicity. Such models will provide more information than the relatively small candidate gene studies performed so far. For implementation of these models into clinical practice, linkage of genotype data to medication prescription systems within electronic health records will be crucial.
Collapse
|
19
|
Pharmacology and toxicology of mycophenolate in organ transplant recipients: an update. Arch Toxicol 2014; 88:1351-89. [PMID: 24792322 DOI: 10.1007/s00204-014-1247-1] [Citation(s) in RCA: 133] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 04/15/2014] [Indexed: 12/22/2022]
Abstract
This review aims to provide an update of the literature on the pharmacology and toxicology of mycophenolate in solid organ transplant recipients. Mycophenolate is now the antimetabolite of choice in immunosuppressant regimens in transplant recipients. The active drug moiety mycophenolic acid (MPA) is available as an ester pro-drug and an enteric-coated sodium salt. MPA is a competitive, selective and reversible inhibitor of inosine-5'-monophosphate dehydrogenase (IMPDH), an important rate-limiting enzyme in purine synthesis. MPA suppresses T and B lymphocyte proliferation; it also decreases expression of glycoproteins and adhesion molecules responsible for recruiting monocytes and lymphocytes to sites of inflammation and graft rejection; and may destroy activated lymphocytes by induction of a necrotic signal. Improved long-term allograft survival has been demonstrated for MPA and may be due to inhibition of monocyte chemoattractant protein 1 or fibroblast proliferation. Recent research also suggested a differential effect of mycophenolate on the regulatory T cell/helper T cell balance which could potentially encourage immune tolerance. Lower exposure to calcineurin inhibitors (renal sparing) appears to be possible with concomitant use of MPA in renal transplant recipients without undue risk of rejection. MPA displays large between- and within-subject pharmacokinetic variability. At least three studies have now reported that MPA exhibits nonlinear pharmacokinetics, with bioavailability decreasing significantly with increasing doses, perhaps due to saturable absorption processes or saturable enterohepatic recirculation. The role of therapeutic drug monitoring (TDM) is still controversial and the ability of routine MPA TDM to improve long-term graft survival and patient outcomes is largely unknown. MPA monitoring may be more important in high-immunological recipients, those on calcineurin-inhibitor-sparing regimens and in whom unexpected rejection or infections have occurred. The majority of pharmacodynamic data on MPA has been obtained in patients receiving MMF therapy in the first year after kidney transplantation. Low MPA area under the concentration time from 0 to 12 h post-dose (AUC0-12) is associated with increased incidence of biopsy-proven acute rejection although AUC0-12 optimal cut-off values vary across study populations. IMPDH monitoring to identify individuals at increased risk of rejection shows some promise but is still in the experimental stage. A relationship between MPA exposure and adverse events was identified in some but not all studies. Genetic variants within genes involved in MPA metabolism (UGT1A9, UGT1A8, UGT2B7), cellular transportation (SLCOB1, SLCO1B3, ABCC2) and targets (IMPDH) have been reported to effect MPA pharmacokinetics and/or response in some studies; however, larger studies across different ethnic groups that take into account genetic linkage and drug interactions that can alter a patient's phenotype are needed before any clinical recommendations based on patient genotype can be formulated. There is little data on the pharmacology and toxicology of MPA in older and paediatric transplant recipients.
Collapse
|
20
|
Vu D, Tellez-Corrales E, Yang J, Qazi Y, Shah T, Naraghi R, Hutchinson IV, Min DI. Genetic polymorphisms of UGT1A8, UGT1A9 and HNF-1α and gastrointestinal symptoms in renal transplant recipients taking mycophenolic acid. Transpl Immunol 2013; 29:155-61. [PMID: 23721685 DOI: 10.1016/j.trim.2013.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 05/16/2013] [Accepted: 05/16/2013] [Indexed: 11/29/2022]
Abstract
Mycophenolic acid (MPA), a widely used immunosuppressant, has a complex metabolism that involves a number of enzymes. Some of its metabolites are thought to be the cause of gastrointestinal (GI) side effects. In this study, we investigated whether polymorphisms of UDP-glucuronosyltransferases (UGT1) A8, 1A9, and hepatocyte nuclear factor (HNF1α) genes or pharmacokinetic parameters of mycophenolic acid (MPA) were associated with the severity of GI symptoms in patients receiving MPA therapy. A total of 109 kidney transplant patients taking mycophenolic acid (MPA) derivatives were genotyped for UGT1A8, 1A9 and HNF1α genes. Among these, a total of 15 patients were participants in the pharmacokinetic study. Severity of GI symptoms was assessed using a validated Gastrointestinal Symptom Rating Scale (GSRS). The overall and subscale GSRS scores were measured at 1 week (baseline), 2 weeks, 3 months and 6 months post-transplantation. In the case of the pharmacokinetic study, EC-MPS was administered and a total of nine blood samples were obtained at -1, 0, 0.5, 1, 2, 4, 6, 8, and 12h. Genotypes of UGT1A8 were significantly associated with the overall GSRS scores at week 1 (p=0.02) and week 2 (p=0.036). Subscales were only statistically significant for constipation at week 1 (p=0.002) and indigestion at week 2 (p=0.02), while UGT1A9 was only significant for the constipation at week 1 (p=0.04). HNF1α genotypes were significantly different at week 1 in the overall GSRS (p=0.004), and for abdominal pain (p=0.04), acid reflux (p=0.036) and constipation subscales (p=0.04). In addition, abdominal pain was statistically significantly different at 3 months and 6 months after transplantation (p=0.03 and 0.02, respectively). In the case of the pharmacokinetic study, we have found some correlations between MPAC0 and constipation (p=0.02) where MPAAUC was correlated with acid reflux (p=0.02) and constipation (p=0.012), MPAGCL/F was correlated to acid reflux, indigestion, constipation and the sum of the GSRS scores (p=0.037, p=0.032, p=0.033 and p=0.04, respectively). Multinomial regression analysis for MPAGCL/F showed a statistical significance for the subscale indigestion and the sum of the GSRS (p=0.033 and p=0.037, respectively). Our data suggests that among patients receiving MPA the UGT1A9 alleles might play a role in determining the severity of early GI side effects, while the HNF1α allele appears to be associated with a later effect as well as early side effects. Our data also showed that some kinetic parameters might predict MPA side effects.
Collapse
Affiliation(s)
- Don Vu
- Mendez National Institute of Transplantation, Los Angeles, CA, United States; Saint Vincent Medical Center, Los Angeles, CA, United States; Western University of Health Sciences, Pomona, CA, United States
| | | | | | | | | | | | | | | |
Collapse
|
21
|
UGT1A9, UGT2B7, and MRP2 genotypes can predict mycophenolic acid pharmacokinetic variability in pediatric kidney transplant recipients. Ther Drug Monit 2013; 34:671-9. [PMID: 23131697 DOI: 10.1097/ftd.0b013e3182708f84] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Mycophenolic acid (MPA) exposure in pediatric patients with kidney transplant receiving body surface area (BSA)-based dosing exhibits large variability. Several genetic variants in glucuronosyltransferases (UGTs) and of multidrug resistance-associated protein 2 (MRP2) have independently been suggested to predict MPA exposure in adult patients with varying results. Here, the combined contribution of these genetic variants to MPA pharmacokinetic variability was investigated in pediatric renal transplant recipients who were on mycophenolic mofetil maintenance therapy. METHODS MPA and MPA-glucuronide concentrations from 32 patients were quantified by high-performance liquid chromatography. MPA exposure (AUC) was estimated using a 4-point abbreviated sampling strategy (predose/trough and 20 minutes, 1 hour, and 3 hours after dose) using a validated pediatric Bayesian estimator. Genotyping was performed for all of the following single nucleotide polymorphisms (SNPs): UGT1A8 830G>A(*3), UGT1A9 98T>C(*3), UGT1A9-440C>T, UGT1A9-2152C>T, UGT1A9-275T>A, UGT2B7-900A>G, and MRP2-24T>C. RESULTS Recipients heterozygous for MRP2-24T>C who also had UGT1A9-440C>T or UGT2B7-900A>G (n = 4), and MRP2-24T>C-negative recipients having both UGT1A9-440C>T and UGT2B7-900A>G (n = 5) showed a 2.2 and 1.7 times higher dose-dependent and BSA-normalized MPA-AUC compared with carriers of no or only 1 UGT-SNP (P < 0.001 and P = 0.01, respectively) (n = 7). Dose-dependent and BSA-normalized predose MPA concentrations were 3.0 and 2.4 times higher, respectively (P < 0.001). Interindividual variability in peak concentrations could be explained by the presence of the UGT1A9-440C>T genotype (P < 0.05). CONCLUSION Our preliminary study demonstrates that combined UGT1A9-440C>T, UGT2B7-900A>G, and MRP2-24T>C polymorphisms can be important predictors of interindividual variability in MPA exposure in the pediatric population.
Collapse
|
22
|
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]
|
23
|
Downing HJ, Pirmohamed M, Beresford MW, Smyth RL. Paediatric use of mycophenolate mofetil. Br J Clin Pharmacol 2013; 75:45-59. [PMID: 22519685 PMCID: PMC3555046 DOI: 10.1111/j.1365-2125.2012.04305.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 04/16/2012] [Indexed: 01/14/2023] Open
Abstract
A number of medications do not have a licence, or label, for use in the paediatric age group nor for the specific indication for which they are being used in children. Over recent years, mycophenolate mofetil has increasingly been used off-label (i.e. off-licence) in adults for a number of indications, including autoimmune conditions; progressively, this wider use has been extended to children. This review summarizes current use of mycophenolate mofetil (MMF) in children, looking at how MMF works, the pharmacokinetics, the clinical conditions for which it is used, the advantages it has when compared with other immunosuppressants and the unresolved issues remaining with use in children. The review aims to focus on off-label use in children so as to identify areas that require further research and investigation. The overall commercial value of MMF is limited because it has now come off patent in adults. Given the increasing knowledge of the pharmacodynamics, pharmacokinetics and pharmacogenomics demonstrating the clinical benefits of MMF, new, formal, investigator-led studies, including trials focusing on the use of MMF in children, would be of immense value.
Collapse
Affiliation(s)
- Heather J Downing
- Department of Women's and Children's Health, Institute of Translational Medicine, The University of Liverpool, Alder Hey Children's NHS Foundation TrustEaton Road, Liverpool L12 2AP, UK
| | - Munir Pirmohamed
- Department of Pharmacology and Therapeutics, The University of LiverpoolAshton Street, Liverpool L69 3GE, UK
| | - Michael W Beresford
- Department of Women's and Children's Health, Institute of Translational Medicine, The University of Liverpool, Alder Hey Children's NHS Foundation TrustEaton Road, Liverpool L12 2AP, UK
| | - Rosalind L Smyth
- Department of Women's and Children's Health, Institute of Translational Medicine, The University of Liverpool, Alder Hey Children's NHS Foundation TrustEaton Road, Liverpool L12 2AP, UK
| |
Collapse
|
24
|
Mycophenolic acid-related diarrhea is not associated with polymorphisms in SLCO1B nor with ABCB1 in renal transplant recipients. Pharmacogenet Genomics 2012; 22:399-407. [PMID: 21878834 DOI: 10.1097/fpc.0b013e32834a8650] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVE We investigated the association between genetic polymorphisms in ABCB1 and SLCO1B and mycophenolic acid (MPA) pharmacokinetics, and MPA-related diarrhea and leukopenia in 338 kidney transplant recipients. METHODS A total of 338 patients participating in an international, randomized-controlled clinical trial were genotyped for ABCB1 and SLCO1B. Patients were all treated with mycophenolate mofetil and either cyclosporine or tacrolimus. MPA-area under the curve (AUCs), MPA-glucuronide AUCs and acylglucuronide-AUCs were measured on days 3 and 10, and months 1, 3, 6, and 12 after kidney transplantation. RESULTS The risk of developing diarrhea was 1.8-fold higher in patients cotreated with tacrolimus compared with patients cotreated with cyclosporine (95% confidence interval: 1.03-3.13; P=0.038). ABCB1 and SLCO1B SNPs were not associated with dose-adjusted exposure to MPA, MPA-glucuronide, nor acylglucuronide-MPA nor with the incidence of diarrhea or leukopenia. CONCLUSION Genotyping for ABCB1 or SLCO1B pretransplantation is unlikely to be of clinical value for individualization of MPA therapy.
Collapse
|
25
|
Optimizing immunosuppressive drug dosing in pediatric renal transplantation. Pharmacol Res 2012; 65:163-7. [DOI: 10.1016/j.phrs.2011.09.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Revised: 09/28/2011] [Accepted: 09/29/2011] [Indexed: 12/17/2022]
|
26
|
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.
Collapse
|
27
|
Saldaña SN, Hooper DK, Froehlich TE, Campbell KM, Prows CA, Sadhasivam S, Nick TG, Seid M, Vinks AA, Glauser TA. Characteristics of successful recruitment in prospective pediatric pharmacogenetic studies. Clin Ther 2011; 33:2072-81. [PMID: 22136977 DOI: 10.1016/j.clinthera.2011.10.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/28/2011] [Indexed: 01/08/2023]
Abstract
BACKGROUND There is a need to explore feasible means of accruing an appropriate study cohort to help fill the knowledge gap between pharmacogenetic contributions to drug response and clinical application in the pediatric population. OBJECTIVES The aim of this study was to identify factors affecting recruitment of eligible subjects in pharmacogenetic studies at a large Midwestern pediatric academic medical center. The objectives were to evaluate recruitment success of ongoing trials and ascertain contributors to differential recruitment rates. We hypothesized that studies with good recruitment of eligible subjects would share characteristics not present in studies with lower than anticipated recruitment. The goal was to better understand barriers to good recruitment in pharmacogenetic studies to help inform future trial and infrastructure design. METHODS Investigators designed a survey with proposed elements of success, which was then completed by lead and/or site investigators of all pharmacogenetics studies at the institution. Results were evaluated using an investigator-developed likelihood of success scoring system. RESULTS Two studies recruited >95% of the approached eligible patients; 4 studies were consistent with investigator-anticipated recruitment (>50%), and 1 study did not meet expected recruitment. A study's total score on the investigator-devised scoring tool correlated well with the proportion of approached patients recruited (Pearson's correlation, r = 0.82; P < 0.001). Multiple factors impacted successful recruitment into these pharmacogenetic studies. Features of studies with successful recruitment included standardized clinical care, an ongoing team-patient relationship, severe and/or life-threatening outcome measures, study coordinator with experience in clinical research, a study medication with few or no alternative treatment options, and active involvement of the research team in clinical care. CONCLUSIONS A scoring system for study characteristics may be useful to calculate the risk of failure for successful recruitment, allow discrimination among characteristics contributing to the risk, and permit study design alterations to improve likelihood of successful recruitment in pediatric pharmacogenetic studies.
Collapse
Affiliation(s)
- Shannon N Saldaña
- Division of Clinical Pharmacology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Abstract
Elevation of the serum bilirubin level is a common, if not universal, finding during the first week of life. This can be a transient phenomenon that resolves spontaneously or can signify a serious or even life-threatening condition. There are many causes of hyperbilirubinemia and related therapeutic and prognostic implications. The diseases in which there is a primary disorder of the metabolism of bilirubin will be reviewed regarding their clinical presentation, pathophysiology, diagnosis, and treatment. These disorders-Gilbert's syndrome and Crigler-Najjar Syndrome-both involve abnormalities in bilirubin conjugation secondary to deficiency of bilirubin uridine diphosphate glucuronosyltransferase. The purpose of this article is to review the current understanding of the genetic polymorphisms that result in these diseases and discuss recent advances in diagnosis and treatment.
Collapse
|
29
|
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]
|
30
|
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.
Collapse
Affiliation(s)
- Hugues Michelon
- Pharmacology Department, Univ Paris-Sud, Bicêtre University Hospital, le Kremlin, Bicêtre, France
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
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.
Collapse
Affiliation(s)
- Catherine M T Sherwin
- Division of Clinical Pharmacology, Cincinnati Childrens Hospital Medical Center, Cincinnati, Ohio 45229-3039, USA
| | | | | | | | | |
Collapse
|
32
|
Developmental pharmacogenetics of immunosuppressants in pediatric organ transplantation. Ther Drug Monit 2011; 32:688-99. [PMID: 21068645 DOI: 10.1097/ftd.0b013e3181f6502d] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cyclosporine, tacrolimus, sirolimus, and mycophenolate mofetil are the primary immunosuppressants used on pediatric organ transplantation. Therapeutic drug monitoring is used in daily practice, because their clinical use is hampered by a narrow therapeutic index and large variability. Tailoring immunosuppressive therapy to the individual patient to optimize efficacy and minimize toxicity is therefore essential. Because research in pharmacogenetics already identified polymorphisms impacting their pharmacokinetic parameters in adults, developmental pharmacogenetics of immunosuppressants holds promises for optimizing dosage regimens and improving clinical outcome in children. In this review, we focus on the impact of age and pharmacogenetics on these immunosuppressants in children undergoing organ transplantation.
Collapse
|
33
|
Age-Related Variability of Mycophenolate Mofetil Exposure in Stable Pediatric Liver Transplant Recipients and Influences of Donor Characteristics. Ther Drug Monit 2009; 31:727-33. [DOI: 10.1097/ftd.0b013e3181c01d07] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|