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Jia HW, Yang HL, Xiong ZL, Deng MH, Wang T, Liu Y, Cheng M. Design, synthesis and antitumor activity evaluation of novel indole acrylamide derivatives as IMPDH inhibitors. Bioorg Chem 2022; 129:106213. [DOI: 10.1016/j.bioorg.2022.106213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 10/13/2022] [Accepted: 10/15/2022] [Indexed: 11/02/2022]
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Brunet M, Millán O. Getting immunosuppression just right: the role of clinical biomarkers in predicting patient response post solid organ transplantation. Expert Rev Clin Pharmacol 2021; 14:1467-1479. [PMID: 34607521 DOI: 10.1080/17512433.2021.1987882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
INTRODUCTION Actually, immunosuppression selection isn't based on individual immune alloreactivity, and immunosuppressive drug dosing is mainly based on the development of toxicity and the achievement of specific target concentrations. Since a successful outcome requires optimal patient risk stratification and treatment, several groups have evaluated candidate biomarkers that have shown promise in the assessment of individual immune responses, the prediction of personal pharmacodynamic effects of immunosuppressive drugs and the prognosis and diagnosis of graft outcomes.. AREAS COVERED This review includes biomarkers that the Scientific Community in Solid Organ Transplantation currently considers to have potential as diagnostic and prognostic biomarkers of graft evolution. We have focused on recent scientific advances and expert recommendations regarding the role of specific and non-specific pharmacodynamic biomarkers that are mainly involved in the T-cell-mediated response. EXPERT OPINION Integral pharmacologic monitoring that combines pharmacokinetics, pharmacogenetics and predictive pharmacodynamic biomarkers may provide crucial information and allow personal adjustment of immunosuppressive drugs at an early stage before severe adverse events ensue. Multicentre, randomized, prospective and interventional trials are needed to fine tune the established cut-off values for each biomarker and the optimal monitoring frequency for each biomarker and to accurately evaluate possible clinical confounding factors to enable correct clinical qualification.
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Affiliation(s)
- Mercè Brunet
- Pharmacology and Toxicology Section, CDB, IDIBAPS, Hospital Clinic of Barcelona, University of Barcelona, Barcelona, Spain.,Biomedical Research Center in Hepatic and Digestive Diseases (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain
| | - Olga Millán
- Pharmacology and Toxicology Section, CDB, IDIBAPS, Hospital Clinic of Barcelona, University of Barcelona, Barcelona, Spain.,Biomedical Research Center in Hepatic and Digestive Diseases (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain
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Inosine 5'-Monophosphate Dehydrogenase Activity for the Longitudinal Monitoring of Mycophenolic Acid Treatment in Kidney Allograft Recipients. Transplantation 2021; 105:916-927. [PMID: 32496356 DOI: 10.1097/tp.0000000000003336] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Mycophenolic acid (MPA) is a standard immunosuppressant in organ transplantation. A simple monitoring biomarker for MPA treatment has not been established so far. Here, we describe inosine 5'-monophosphate dehydrogenase (IMPDH) monitoring in erythrocytes and its application to kidney allograft recipients. METHODS IMPDH activity measurements were performed using a high-performance liquid chromatography assay. Based on 4203 IMPDH measurements from 1021 patients, we retrospectively explored the dynamics early after treatment start. In addition, we analyzed the influence of clinically relevant variables on IMPDH activity in a multivariate model using data from 711 stable patients. Associations between IMPDH activity and clinical events were evaluated in hospitalized patients. RESULTS We found that IMPDH activity reflects MPA exposure after 8 weeks of constant dosing. In addition to dosage, body mass index, renal function, and coimmunosuppression affected IMPDH activity. Significantly lower IMPDH activities were found in patients with biopsy-proven acute rejection as compared to patients without rejection (median [interquartile range]: 696 [358-1484] versus 1265 [867-1618] pmol xanthosine-5'-monophosphate/h/mg hemoglobin, P < 0.001). The highest IMPDH activities were observed in hospitalized patients with clinically evident MPA toxicity as compared to patients with hospitalization not related to MPA treatment (1548 [1021-2270] versus 1072 [707-1439] pmol xanthosine-5'-monophosphate/h/mg hemoglobin; P < 0.001). Receiver operating characteristic curve analyses underlined the usefulness of IMPDH to predict rejection episodes (area, 0.662; confidence interval, 0.584-0.740; P < 0.001) and MPA-associated adverse events (area, 0.632; confidence interval, 0.581-0.683; P < 0.001), respectively. CONCLUSIONS IMPDH measurement in erythrocytes is a novel and useful strategy for the longitudinal monitoring of MPA treatment.
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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: 76] [Impact Index Per Article: 25.3] [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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Klaasen RA, Bergan S, Bremer S, Hole K, Nordahl CB, Andersen AM, Midtvedt K, Skauby MH, Vethe NT. Pharmacodynamic assessment of mycophenolic acid in resting and activated target cell population during the first year after renal transplantation. Br J Clin Pharmacol 2020; 86:1100-1112. [PMID: 31925806 PMCID: PMC7256122 DOI: 10.1111/bcp.14218] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 12/10/2019] [Accepted: 12/19/2019] [Indexed: 12/31/2022] Open
Abstract
Aims To explore the pharmacodynamics of mycophenolic acid (MPA) through inosine monophosphate dehydrogenase (IMPDH) capacity measurement and purine levels in peripheral blood mononuclear cells (PBMC) longitudinally during the first year after renal transplantation (TX). Methods PBMC were isolated from renal recipients 0–4 days prior to and 6–9 days, 5–7 weeks and 1 year after TX (before and 1.5 hours after dose). IMPDH capacity and purine (guanine and adenine) levels were measured in stimulated and nonstimulated PBMC. Results Twenty‐nine patients completed the follow‐up period, of whom 24 received MPA. In stimulated PBMC, the IMPDH capacity (pmol 10−6 cells min−1) was median (interquartile range) 127 (95.8–147) before TX and thereafter 44.9 (19.2–93.2) predose and 12.1 (4.64–23.6) 1.5 hours postdose across study days after TX. The corresponding IMPDH capacity in nonstimulated PBMC was 5.71 (3.79–6.93), 3.35 (2.31–5.62) and 2.71 (1.38–4.08), respectively. Predose IMPDH capacity in nonstimulated PBMC increased with time, reaching pre‐TX values at 1 year. In stimulated PBMC, both purines were reduced before (median 39% reduction across days after TX) and after (69% reduction) dose compared to before TX. No alteration in the purine levels was observed in nonstimulated PBMC. Patients needing dose reductions during the first year had lower pre‐dose IMPDH capacity in nonstimulated PBMC (1.87 vs 3.00 pmol 10−6 cells min−1, P = .049) at 6–9 days. Conclusion The inhibitory effect of MPA was stronger in stimulated PBMC. Nonstimulated PBMC became less sensitive to MPA during the first year after TX. Early IMPDH capacity appeared to be predictive of dose reductions.
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Affiliation(s)
| | - Stein Bergan
- Department of Pharmacology, Oslo University Hospital, Oslo, Norway
| | - Sara Bremer
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
| | - Kristine Hole
- Department of Pharmacology, Oslo University Hospital, Oslo, Norway
| | | | | | - Karsten Midtvedt
- Department of Transplantation Medicine, Oslo University Hospital, Oslo, Norway
| | - Morten Heier Skauby
- Department of Transplantation Medicine, Oslo University Hospital, Oslo, Norway
| | - Nils Tore Vethe
- Department of Pharmacology, Oslo University Hospital, Oslo, Norway
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Lea-Henry T, Chacko B. Management considerations in the failing renal allograft. Nephrology (Carlton) 2017; 23:12-19. [DOI: 10.1111/nep.13165] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/08/2017] [Indexed: 12/20/2022]
Affiliation(s)
- Tom Lea-Henry
- Nephrology and Transplantation Unit; John Hunter Hospital; Newcastle New South Wales Australia
| | - Bobby Chacko
- Nephrology and Transplantation Unit; John Hunter Hospital; Newcastle New South Wales Australia
- School of Medicine and Public Health; University of Newcastle; Newcastle New South Wales Australia
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Highly selective inhibition of IMPDH2 provides the basis of antineuroinflammation therapy. Proc Natl Acad Sci U S A 2017; 114:E5986-E5994. [PMID: 28674004 DOI: 10.1073/pnas.1706778114] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Inosine monophosphate dehydrogenase (IMPDH) of human is an attractive target for immunosuppressive agents. Currently, small-molecule inhibitors do not show good selectivity for different IMPDH isoforms (IMPDH1 and IMPDH2), resulting in some adverse effects, which limit their use. Herein, we used a small-molecule probe specifically targeting IMPDH2 and identified Cysteine residue 140 (Cys140) as a selective druggable site. On covalently binding to Cys140, the probe exerts an allosteric regulation to block the catalytic pocket of IMPDH2 and further induces IMPDH2 inactivation, leading to an effective suppression of neuroinflammatory responses. However, the probe does not covalently bind to IMPDH1. Taken together, our study shows Cys140 as a druggable site for selectively inhibiting IMPDH2, which provides great potential for development of therapy agents for autoimmune and neuroinflammatory diseases with less unfavorable tolerability profile.
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van Gelder T, Hesselink DA. Mycophenolate revisited. Transpl Int 2016; 28:508-15. [PMID: 25758949 DOI: 10.1111/tri.12554] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 02/03/2015] [Accepted: 03/06/2015] [Indexed: 12/11/2022]
Abstract
The patent of mycophenolate mofetil (MMF) has expired, and for enteric-coated mycophenolate sodium (EC-MPS), this will happen in 2017. In the twenty years these drugs have been used, they have become extremely popular. In this review, the reasons for the popularity of mycophenolate are discussed, including the benefits compared to azathioprine. MMF and EC-MPS are therapeutically equivalent. Although neither is considered to be a narrow therapeutic index drug, this should not lead to careless switching between the innovator drug and generic formulations, or between one generic formulation and another. The pipeline of new immunosuppressive drugs is dry, and it is very likely that we will be using mycophenolate for many more years to come as a first-line immunosuppressive drug in our transplant population. Whether or not the development of donor-specific anti-HLA antibodies is related to drug exposure (mycophenolic acid concentrations) remains to be investigated.
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Affiliation(s)
- Teun van Gelder
- Department of Hospital Pharmacy, Erasmus MC, University Medical Center, Rotterdam, The Netherlands; Department of Internal Medicine, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
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Bergan S, Bremer S, Vethe NT. Drug target molecules to guide immunosuppression. Clin Biochem 2015; 49:411-8. [PMID: 26453533 DOI: 10.1016/j.clinbiochem.2015.10.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 09/25/2015] [Accepted: 10/03/2015] [Indexed: 10/22/2022]
Abstract
The individual and interindividual variability of response to immunosuppressants combined with the prevailing concept of lifelong immunosuppression following any organ transplantation motivates the search for methods to further individualize such therapy. Traditional therapeutic drug monitoring, adapting dose according to concentrations in blood, targets the pharmacokinetic variability. It has been increasingly recognized, however, that there is also a considerable variability in the response to a given concentration. Attempts to overcome this variability in response include the efforts to identify relevant targets and methods for pharmacodynamic monitoring. For several of the currently used immunosuppressants there is experimental data suggesting markers that are relevant as indicators for individual monitoring of the effects of these drugs. There are also some clinical data to support these approaches; however what is generally missing, are studies that in a prospective manner demonstrates the benefits and effects on outcome. The monitoring of antithymocyte globulin by lymphocyte subset counts is actually the only well established example of pharmacodynamic monitoring. For drugs such as MPA and mTOR inhibitors, there are candidates such as IMPDH activity expression and p70SK6 phosphorylation status, respectively. The monitoring of CNIs using assays for NFAT RGE, either alone or combined with concentration measurements, is already well documented. Even here, some further investigations relating to the categories of organ transplant, combination of immunosuppressants etc. will be requested. Although some further standardization of the assay is warranted and there is a need for specific recommendations of target levels and how to adjust dose, the NFAT RGE approach to pharmacodynamic monitoring of CNIs may be close to implementation in clinical routine.
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Affiliation(s)
- Stein Bergan
- Oslo University Hospital, Department of Pharmacology, Oslo, Norway; University of Oslo, School of Pharmacy, Oslo, Norway.
| | - Sara Bremer
- Oslo University Hospital, Department of Medical Biochemistry, Oslo, Norway
| | - Nils Tore Vethe
- Oslo University Hospital, Department of Pharmacology, Oslo, Norway
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Tacrolimus exposure and mycophenolate pharmacokinetics and pharmacodynamics early after liver transplantation. Ther Drug Monit 2014; 36:46-53. [PMID: 24081206 DOI: 10.1097/ftd.0b013e31829dcb66] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
BACKGROUND Mycophenolic acid (MPA) and tacrolimus play important roles in immunosuppressive therapy after solid organ transplantation (Tx) and show large intra- and interindividual pharmacokinetic (PK) variabilities. The purpose of this study was to describe the intra- and interindividual variabilities of MPA and tacrolimus PKs during the first 3 weeks after adult liver transplantation. Furthermore, inosine monophosphate dehydrogenase activity was investigated. MATERIALS This study describes PK and pharmacodynamic parameters of MPA and the PKs of tacrolimus in 16 liver transplant recipients, in 4 follow-up periods (I-IV). RESULTS The area under the concentration-time curve (AUC(0-12 hours)) for tacrolimus was low early after Tx (eg, median 78.6 around day 4) and variable in all 4 periods ranging from 3.8 to 267 μg h/L, whereas the predose concentrations (C₀) were 0.0-17.9 μg/L. From periods I to IV, the tacrolimus dose was doubled and the median dose per body weight-adjusted AUC(0-12 hours) increased by 123% (P = 0.017). The AUC(0-12 hours) of MPA was in the range 8.6-57.4 mg h/L, with median values from 21.9 to 27.8 mg h/L, whereas C₀ was between 0.0 and 7.3 mg/L in the 4 periods (medians from 1.2 to 1.6 mg/L). The maximum inhibition of inosine monophosphate dehydrogenase within a dose interval ranged from 9.5% to 100%. CONCLUSIONS This study confirmed the large variability in the PKs of tacrolimus and MPA in liver transplant recipients. In particular, the MPA AUC(0-12 hours) was consistently low in all 4 periods. We also observed a low tacrolimus exposure during the first days after transplant compared with the following weeks.
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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.
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Dong M, Fukuda T, Vinks AA. Optimization of Mycophenolic Acid Therapy Using Clinical Pharmacometrics. Drug Metab Pharmacokinet 2014; 29:4-11. [DOI: 10.2133/dmpk.dmpk-13-rv-112] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Dostalek M, Gohh RY, Akhlaghi F. Inosine monophosphate dehydrogenase expression and activity are significantly lower in kidney transplant recipients with diabetes mellitus. Ther Drug Monit 2013; 35:374-83. [PMID: 23666569 PMCID: PMC4109137 DOI: 10.1097/ftd.0b013e3182852697] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Inosine 5'-monophosphate dehydrogenase (IMPDH) is a target of the immunosuppressive drug, mycophenolic acid (MPA). A 12-hour clinical pharmacokinetic and pharmacodynamic study was conducted to compare IMPDH1 and IMPDH2 gene expression, IMPDHI and IMPDHII protein levels, and enzyme activity between kidney transplant recipients with respect to diabetes status. METHODS Nondiabetic (ND, n = 11) and diabetic (D, n = 9) kidney transplant recipients and on nontransplant nondiabetic (n = 10) and diabetic (n = 10) volunteers were included in the study. RESULTS Area under the effect curve values for gene expression: IMPDH1 [ND: 22.1 (13.8-31.3) versus D: 4.5 (2.3-6.5), P < 0.001] and IMPDH2 [ND: 15.3 (11.0-21.7) versus D: 6.1 (4.6-8.6), P < 0.001], protein level: IMPDHI [ND: 1.0 (0.5-1.3) versus 0.5 (0.4-0.7), P = 0.002] and IMPDHII [ND: 1.0 (0.6-1.6) versus D: 0.7 (0.6-0.8) P < 0.001] and enzyme activity [ND: 180 (105-245) versus D: 29.9 (15.3-35.6) µmole·s(-1)·mole(-1) adenosine monophosphate, P < 0.001] was significantly lower in transplant recipients with diabetes. Similar results were observed in nontransplanted volunteers. Kinetic studies of MPA-mediated suppression of IMPDH activity in nontransplanted individuals revealed an approximately 2.5-fold lower half-maximum effective concentration (EC50) for diabetic as compared with nondiabetic [ND: 50.2 (49.8-50.7) versus D: 15.8 (15.6-16.3) nmole/L, P = 0.004] volunteers. This difference was not related to several IMPDH gene variants. CONCLUSIONS This study indicates a significantly lower IMPDH gene expression, protein level, and enzyme activity in diabetic patients. Further clinical studies in a larger number of patients are warranted to verify whether MPA dosing must be optimized for kidney transplant recipients with diabetes mellitus.
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Affiliation(s)
- Miroslav Dostalek
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI, USA
| | - Reginald Y. Gohh
- Division of Organ Transplantation, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
| | - Fatemeh Akhlaghi
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI, USA
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Molinaro M, Chiarelli LR, Biancone L, Castagneto M, Boschiero L, Pisani F, Sabbatini M, Sandrini S, Arbustini E, Tinelli C, Regazzi M, Schena FP, Segoloni GP. Monitoring of inosine monophosphate dehydrogenase activity and expression during the early period of mycophenolate mofetil therapy in de novo renal transplant patients. Drug Metab Pharmacokinet 2012; 28:109-17. [PMID: 22892445 DOI: 10.2133/dmpk.dmpk-12-rg-048] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Measurement of inosine-monophosphate dehydrogenase (IMPDH) activity or gene expression was used as a further approach in pharmacokinetics (PK)/pharmacodynamic (PD)-guided mycophenolate mofetil (MMF) therapy. Forty-four de novo kidney transplant patients were enrolled; 35 of these completed the study, and were followed for 24 weeks for clinical status, PK parameters, IMPDH activity and IMPDH1/2 gene expression. IMPDH activity and expression were measured in peripheral blood mononuclear cells before transplant and at week 2,4,12 and 24, drawn before (t0) and 2 h (t2 h) after MMF administration. No significant correlation was found between IMPDH activity/expression and PK parameters. For both genes, significant enhancement in t2 h expression was observed, then decreases towards week 24 with a trend following steroid dosages. Seven patients experienced acute rejection (AR) and exhibited significantly higher pre-transplant expression of both IMPDH1 (median 3.42 vs. 0.84; p=0.0025), and IMPDH2 genes (135 vs. 104; p=0.0218) with respect to non-rejecting patients. A significant association was also found between pre-transplant IMPDH1 mRNA and haematological complications (p=0.032). This study suggests that high steroid dosages may influence IMPDH1/2 expression, hampering their use as a PD biomarker, particularly during the early post-transplant period. The measurement of pre-transplant levels of IMPDH1/2 may contribute to prediction of individual drug responsiveness to improve the clinical management of patients in MMF therapy.
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Affiliation(s)
- Mariadelfina Molinaro
- Clinical Pharmacokinetics in Transplantation and Autoimmune Diseases, Foundation IRCCS Policlinico S. Matteo, Pavia, Italy.
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Abboudi H, Macphee IA. Individualized immunosuppression in transplant patients: potential role of pharmacogenetics. PHARMACOGENOMICS & PERSONALIZED MEDICINE 2012; 5:63-72. [PMID: 23226063 PMCID: PMC3513229 DOI: 10.2147/pgpm.s21743] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/16/2012] [Indexed: 12/29/2022]
Abstract
The immunosuppressive drugs used to prevent the rejection of transplanted organs have a narrow therapeutic index. Under treatment results in episodes of rejection leading to either damage or loss of the organ. Over immunosuppression increases the risk of infection and malignancy as well as drug specific complications including diabetes mellitus and nephrotoxicity. There is wide variation in the drug dose required to achieve target blood concentrations and there is often dissociation between pharmacokinetics and pharmacodynamics. Currently, immunosuppressive drug treatment is individualized based on a clinical assessment of the risk of rejection or toxicity. Therapeutic drug monitoring is routinely employed for several immunosuppressive drugs. Pharmacogenetics has the potential to complement therapeutic drug monitoring but clinical benefit has yet to be demonstrated. Novel biomarker-based approaches to risk stratification and pharmacodynamic monitoring are under development and are ready for clinical trials.
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Affiliation(s)
- Hamid Abboudi
- Division of Clinical Sciences, Renal Medicine, St George's, University of London, London, UK
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Association Between Pharmacodynamic Biomarkers and Clinical Events in the Early Phase After Kidney Transplantation: A Single-Center Pilot Study. Ther Drug Monit 2011; 33:341-9. [DOI: 10.1097/ftd.0b013e3182188675] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Polymorphisms in type I and II inosine monophosphate dehydrogenase genes and association with clinical outcome in patients on mycophenolate mofetil. Pharmacogenet Genomics 2011; 20:537-43. [PMID: 20679962 DOI: 10.1097/fpc.0b013e32833d8cf5] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
BACKGROUND Type I and II inosine monophosphate dehydrogenases (IMPDH) are the targets of mycophenolic acid (MPA), a widely used immunosuppressant. The aims of this study were: to check the presence of controversial polymorphisms in the IMPDH II gene; to look for new ones; and to investigate potential associations between the most frequent SNPs in both IMPDH genes and clinical outcome in renal transplant recipients. METHODS The DNA and clinical data of 456 patients from two clinical trials were collected. We sequenced the IMPDH II gene in 80 patients and we genotyped the 456 patients' DNA for the IMPDH II rs4974081, rs11706052, 787C>T and the IMPDH I rs2278293 and rs2278294 SNPs, all of which were earlier reported to be potentially involved in MPA treatment related outcome. We investigated the associations of biopsy proven acute rejection (BPAR), leucopenia, cytomegalovirus infections and other infections with these IMPDH polymorphisms, as well as with demographic, biological and treatment data using multivariate analysis. RESULTS Many IMPDH II variant alleles referenced in Genbank were not detected and no new polymorphisms were identified. In the whole group of 456 patients, the IMPDH I rs2278294 SNP was associated with a lower risk of BPAR and a higher risk of leucopenia over the first year post-transplantation. No other IMPDH I or IMPDH II polymorphism was significantly associated with any clinical outcome. Interestingly, calcineurin inhibitor and MPA exposures below the therapeutic range increased the risk of BPAR. Cytomegalovirus infection was the factor most closely linked with leucopenia, whereas tacrolimus was associated with fewer infections than cyclosporine. CONCLUSION IMPDH II genotyping may not improve MPA treatment outcome over the first year post-transplantation, in contrast to MPA and calcineurine inhibitor therapeutic drug monitoring and IMPDH I genotyping.
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Chiarelli LR, Molinaro M, Libetta C, Tinelli C, Cosmai L, Valentini G, Dal Canton A, Regazzi M. Inosine monophosphate dehydrogenase variability in renal transplant patients on long-term mycophenolate mofetil therapy. Br J Clin Pharmacol 2010; 69:38-50. [PMID: 20078611 DOI: 10.1111/j.1365-2125.2009.03542.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT * Mycophenolic acid (MPA) is a potent, selective and reversible inhibitor of inosine 5'-monophosphate dehydrogenase (IMPDH), the rate-limiting enzyme for de novo guanosine triphosphate biosynthesis. * The large IMPDH interindividual variability could be responsible for the differences in therapeutic effects and side-effects observed with MPA. * Induction of IMPDH activity has been observed in whole blood during immunosuppressive therapy. WHAT THIS STUDY ADDS * Our data were acquired in long-term mycophenolate mofetil-treated renal transplant recipients on different combinations of immunosuppressive agents (ciclosporin, tacrolimus, sirolimus) and with different treatment duration (up to 8.8 years post transplant). * The increasing trend in IMPDH activity that we observed throughout our 12-month observation period was significantly higher in rejecting than in nonrejecting subjects. AIMS Long-term mycophenolate mofetil (MMF) therapy may induce inosine 5'-monophosphate dehydrogenase (IMPDH) activity in peripheral blood mononuclear cells (PBMCs), thus decreasing MMF immunosuppressive properties. Pharmacodynamic monitoring was used to investigate whether biological activity is altered after long-term therapy. METHODS IMPDH activity was measured in PBMC samples from 54 stable kidney transplant patients, already on MMF (for at least 3 months), before (t(0)) and 2 h after (t(2)) MMF morning dose administration; levels were monitored for up to 15 months, together with total mycophenolic acid (MPA) and free MPA concentrations. RESULTS During the 15 months' monitoring, t(0) IMPDH activity in transplant recipients increased from 5.9 +/- 3.7 nmol h(-1) mg(-1)[95% confidence interval (CI) 4.9, 6.9] to 9.0 +/- 3.9 nmol h(-1) mg(-1) (95% CI 7.2, 10.8), with an intra- and interpatient variability of 28% and 42%. Five patients experienced acute rejection during the follow-up: t(0) IMPDH activity was increased during rejection vs. nonrejection, and the trend was significantly higher in rejecting than in nonrejecting subjects for the whole monitoring period. CONCLUSIONS Even though a correlation has been found between IMPDH activity and rejection, its efficacy as a predictive tool in long-term transplant outcomes may be affected by high interpatient variability; on the other hand, continuous monitoring of the IMPDH trend could make an effective prognostic parameter of rejection. Other trials also including pre-transplant data on both IMPDH expression and activity are warranted to better assess their role as biomarkers for MPA effect in clinical practice.
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Affiliation(s)
- Laurent R Chiarelli
- Department of Biochemistry, University of Pavia, Pharmacokinetics Unit, Pavia, Italy
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Burckart GJ, Amur S. Update on the clinical pharmacogenomics of organ transplantation. Pharmacogenomics 2010; 11:227-36. [PMID: 20136361 DOI: 10.2217/pgs.09.177] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Organ transplantation suffers from a static graft and patient survival rate, and a high incidence of serious adverse drug effects. The pharmacogenomics of organ transplantation has emerged only recently and is complementary to the immunogenetic information that has accumulated over the past decade. Gene polymorphism studies have focused on the genes that interact across the group of immunosuppressants, including ciclosporin, tacrolimus, sirolimus and corticosteroids. The polymorphisms that hold the most potential for use in a drug selection algorithm are in genes CYP3A5, ABCB1, IMPDH1 and IMPDH2, and cytokines and growth factors. Gene-expression arrays have led to gene-expression testing, such as the use of AlloMap((R)) with heart transplant patients. The expanded use of gene-expression assays, proteomics and drug selection algorithms in organ transplantation will progress slowly and may be outpaced by drug test co-development programs for new transplant drugs. In the future, clinical pharmacogenomics will be a routine part of patient care for organ transplant patients.
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Affiliation(s)
- Gilbert J Burckart
- Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, 10903 New Hampshire Avenue, Building 51, Room 3184, Silver Spring, MD 20993, USA.
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Inosine monophosphate dehydrogenase messenger RNA expression is correlated to clinical outcomes in mycophenolate mofetil-treated kidney transplant patients, whereas inosine monophosphate dehydrogenase activity is not. Ther Drug Monit 2010; 31:549-56. [PMID: 19704402 DOI: 10.1097/ftd.0b013e3181b7a9d0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Measurement of the pharmacodynamic biomarker inosine monophosphate dehydrogenase (IMPDH) activity in renal transplant recipients has been proposed to reflect the biological effect better than using pharmacokinetic parameters to monitor mycophenolate mofetil therapy. The IMPDH assays are however labor intensive and this complicates implementation into patient care. Quantification of IMPDH messenger RNA (mRNA) could form an attractive alternative. This study was designed to correlate IMPDH mRNA levels with IMPDH activity and clinical outcome in renal transplant recipients. From a cohort of 101 renal transplant patients, blood samples were drawn pre transplantation and at 4 times after transplantation. IMPDH activity, IMPDH type 1 and type 2 mRNA levels, and mycophenolic acid concentrations were measured and correlated to clinical outcomes. No correlation was found between IMPDH type 1 and type 2 mRNA levels and IMPDH activity in pre- and posttransplant samples. A significant increase in IMPDH mRNA levels was found between day 6 and day 140 after transplantation. IMPDH type 1 and type 2 mRNA levels before transplant showed a trend toward statistically significant higher levels in patients with an acute rejection (P = 0.052 and P = 0.058). After transplant, the IMPDH type 1 and type 2 mRNA levels were significantly lower in patients with an acute rejection (P = 0.026 and P = 0.007). We conclude that IMPDH mRNA levels do not correlate with IMPDH activity but are nevertheless correlated with acute rejections. Furthermore, although the regulation of the expression of the 2 isoforms is presumed to be different, in this study, the changes in the expression of type 1 mRNA closely paralleled those of type 2.
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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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Sabbatini M, Capone D, Gallo R, Pisani A, Polichetti G, Tarantino G, Gentile A, Rotaia E, Federico S. EC-MPS permits lower gastrointestinal symptom burden despite higher MPA exposure in patients with severe MMF-related gastrointestinal side-effects. Fundam Clin Pharmacol 2009; 23:617-24. [PMID: 19656208 DOI: 10.1111/j.1472-8206.2009.00711.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Gastrointestinal (GI) adverse events in renal transplant patients are a common cause of mycophenolate mofetil (MMF) dose reductions, which result in an increased risk of graft rejection because of a low immunosuppression. This study investigated whether conversion from MMF to enteric-coated mycophenolate sodium (EC-MPS) in renal transplant patients with serious GI side-effects, alleviated these symptoms and allowed administration of higher doses of EC-MPS. Nineteen renal transplant patients with severe MMF-related GI side-effects underwent a progressive reduction in MMF dose until symptoms disappeared. At this point, 12-h AUC(MMF) was evaluated and patients were shifted to an equimolar dose of EC-MPS. The EC-MPS dose was then progressively increased until the highest recommended dose was reached or GI symptoms re-appeared. Four weeks post-conversion, AUC(EC-MPS) was determined. Conversion led to a mean increase in EC-MPS dose of 68% (P < 0.0001), with a corresponding rise in AUC(0-12) (60.5%, P < 0.0006) associated with significant benefits in terms of both quality of life (Kidney Transplant Questionnaire, P < 0.01) and GI symptoms (Gastrointestinal Symptom Rating Scale, P < 0.0001), using validated questionnaires. In five of 19 patients, the EC-MPS dose could not be increased because of the prompt insurgence of GI symptoms. Renal function and biochemical parameters remained stable post-conversion and no rejection episodes occurred. These findings suggest that, in selected patients, EC-MPS may be better tolerated than MMF when GI symptoms are particularly important and permits higher mycophenolic acid exposure, when required.
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Affiliation(s)
- Massimo Sabbatini
- Department of Nephrology, Day-Hospital of Renal Transplantation, University Federico II, Naples, Italy
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Interpatient variability in IMPDH activity in MMF-treated renal transplant patients is correlated with IMPDH type II 3757T > C polymorphism. Pharmacogenet Genomics 2009; 19:626-34. [PMID: 19617864 DOI: 10.1097/fpc.0b013e32832f5f1b] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
OBJECTIVES The active metabolite of mycophenolate mofetil (MMF), mycophenolic acid, inhibits the activity of the target enzyme inosine monophosphate dehydrogenase (IMPDH). The aim of this study was to correlate eight different single nucleotide polymorphisms of the IMPDH type II gene to the activity of the IMPDH enzyme to explain between-patient differences in IMPDH activity. METHODS AND RESULTS In a prospective study, we measured IMPDH activity, mycophenolic acid plasma concentrations, and eight polymorphisms of IMPDH type II in de novo kidney transplant recipients, 6 days posttransplantation while on MMF treatment. Polymorphisms in the IMPDH type II gene were only observed for the IMPDH type II 3757T > C (rs11706052) single nucleotide polymorphism. Ten of 101 patients (10%) were heterozygous and two of 101 patients (2%) homozygous for IMPDH type II 3757T > C. The allele frequency was 6.9%. The IMPDH activity over 12 h (AUC(act)) was 49% higher for patients with an IMPDH type II 3757C variant [n = 12 vs. n = 68; 336 (95% confidence interval: 216-521) vs. 227 (95% confidence interval: 198-260) hmicromol/s/mol adenosine monophosphate; P = 0.04]. The IMPDH activity measured before transplantation (Act(pre-Tx)) was not significantly different between IMPDH type II 3757TT wild-type and variant carrier patients (P = 0.99). CONCLUSION We report that the IMPDH type II 3757T > C polymorphism is associated with an increased IMPDH activity in MMF-treated renal transplant patients. This polymorphism explains 8.0% of the interpatient variability in IMPDH activity.
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Daniel V, Opelz G. Clinical Relevance of Immune Monitoring in Solid Organ Transplantation. Int Rev Immunol 2009; 28:155-84. [DOI: 10.1080/08830180902929404] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Bremer S, Vethe NT, Rootwelt H, Jørgensen PF, Stenstrøm J, Holdaas H, Midtvedt K, Bergan S. Mycophenolate pharmacokinetics and pharmacodynamics in belatacept treated renal allograft recipients - a pilot study. J Transl Med 2009; 7:64. [PMID: 19635156 PMCID: PMC2724496 DOI: 10.1186/1479-5876-7-64] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Accepted: 07/27/2009] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Mycophenolic acid (MPA) is widely used as part of immunosuppressive regimens following allograft transplantation. The large pharmacokinetic (PK) and pharmacodynamic (PD) variability and narrow therapeutic range of MPA provide a potential for therapeutic drug monitoring. The objective of this pilot study was to investigate the MPA PK and PD relation in combination with belatacept (2nd generation CTLA4-Ig) or cyclosporine (CsA). METHODS Seven renal allograft recipients were randomized to either belatacept (n = 4) or cyclosporine (n = 3) based immunosuppression. Samples for MPA PK and PD evaluations were collected predose and at 1, 2 and 13 weeks posttransplant. Plasma concentrations of MPA were determined by HPLC-UV. Activity of inosine monophosphate dehydrogenase (IMPDH) and the expressions of two IMPDH isoforms were measured in CD4+ cells by HPLC-UV and real-time reverse-transcription PCR, respectively. Subsets of T cells were characterized by flow cytometry. RESULTS The MPA exposure tended to be higher among belatacept patients than in CsA patients at week 1 (P = 0.057). Further, MPA concentrations (AUC0-9 h and C0) increased with time in both groups and were higher at week 13 than at week 2 (P = 0.031, n = 6). In contrast to the postdose reductions of IMPDH activity observed early posttransplant, IMPDH activity within both treatment groups was elevated throughout the dosing interval at week 13. Transient postdose increments were also observed for IMPDH1 expression, starting at week 1. Higher MPA exposure was associated with larger elevations of IMPDH1 (r = 0.81, P = 0.023, n = 7 for MPA and IMPDH1 AUC0-9 h at week 1). The maximum IMPDH1 expression was 52 (13-177)% higher at week 13 compared to week 1 (P = 0.031, n = 6). One patient showed lower MPA exposure with time and did neither display elevations of IMPDH activity nor IMPDH1 expression. No difference was observed in T cell subsets between treatment groups. CONCLUSION The significant influence of MPA on IMPDH1 expression, possibly mediated through reduced guanine nucleotide levels, could explain the elevations of IMPDH activity within dosing intervals at week 13. The present regulation of IMPDH in CD4+ cells should be considered when interpreting measurements of IMPDH inhibition.
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Affiliation(s)
- Sara Bremer
- Department of Medical Biochemistry, Rikshospitalet University Hospital, Oslo, Norway.
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Pretransplant Pharmacodynamic Analysis of Immunosuppressive Agents Using CFSE-Based T-Cell Proliferation Assay. Clin Pharmacol Ther 2009; 86:285-9. [DOI: 10.1038/clpt.2009.61] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Pharmacodynamics of mycophenolic acid in CD4+ cells: a single-dose study of IMPDH and purine nucleotide responses in healthy individuals. Ther Drug Monit 2009; 30:647-55. [PMID: 18806697 DOI: 10.1097/ftd.0b013e31818955c3] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Mycophenolate mofetil is used in rejection prophylaxis after allograft transplantation. The highly variable pharmacokinetics and pharmacodynamics (PD) of the active moiety mycophenolic acid (MPA) render this drug attractive for therapeutic monitoring. The aim of this study was to characterize the exposure-response relationship for MPA to guide future strategies for individualized therapy based on PD monitoring. A single-dose (100, 250, 500, and 1000 mg mycophenolate mofetil) crossover exposure-response study of MPA PD in CD4 cells was performed in 5 healthy individuals. The activity of inosine 5'-monophosphate dehydrogenase (IMPDH) at time 0 ranged from 1.2 to 7.2 pmol per 10 cells/min. IMPDH was strongly inhibited by MPA; MPA EC50 (concentration required for 50% inhibition) of 2.3 mg/L was determined by a pooled data analysis. Decreased IMPDH gene expression was associated with the exposure to MPA. There were no immediate reductions of guanine nucleotides. On the contrary, a trend toward increased guanosine triphosphate was observed. IMPDH activity AUC0-12h approached maximum reduction at MPA AUC0-12h 22 mg x h/L (corresponding to the 500 mg dose), whereas plasma concentrations exceeding approximately 6 mg/L did not further increase the IMPDH inhibition. The results suggest that guanine nucleotides in circulating lymphocytes may not serve as immediate response biomarkers to MPA. Strategies for preventing over- or underexposure to MPA may be developed by means of IMPDH activity combined with MPA concentration measurement.
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Bremer S, Vethe NT, Rootwelt H, Bergan S. Expression of IMPDH1 is regulated in response to mycophenolate concentration. Int Immunopharmacol 2008; 9:173-80. [PMID: 19010451 DOI: 10.1016/j.intimp.2008.10.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2008] [Revised: 10/23/2008] [Accepted: 10/27/2008] [Indexed: 10/21/2022]
Abstract
Inosine 5'-monophosphate dehydrogenase (IMPDH) catalyzes de novo guanine nucleotide synthesis. Mycophenolic acid (MPA) exerts immunosuppressive effects by inhibiting IMPDH. The aim of this study was to investigate gene expressions of two IMPDH isoforms, during in vivo exposure to MPA. Healthy volunteers (n=5) were given single doses of 100, 250, 500 and 1000 mg mycophenolate mofetil (MMF). Blood was sampled pre-dose and at 1, 2, 4, 6, 8, 12, and 24 h post-dose. The expressions of IMPDH 1 and 2 were quantified in CD4+ cells and whole blood by real-time reverse transcription-PCR. Following MMF doses of 500 mg, the expression of IMPDH 1 and 2 in CD4+ cells was reduced 39% (P=0.043) and 10% (P=0.043), respectively. Smaller reductions (ns) were observed after 1000 mg MMF. Similar trends were demonstrated for whole blood. The largest reductions of IMPDH1 occurred at MPA AUC(0-12 h) of 20 mg h/L. Below this, increasing MPA exposure correlated with larger reductions of IMPDH1 expression (CD4+ cells: r=-0.82, P<0.001, and whole blood: r=-0.50, P=0.04, n=17), while higher MPA exposure seemed to be associated with smaller reductions of expression (CD4+ cells: r=0.42, ns, and whole blood: r=0.77, P=0.039, n=8). The concentration-dependent modulation of IMPDH 1 and 2 expressions by MPA might impact IMPDH activity. Knowledge of the regulation of the two IMPDH isoenzymes in vivo by MPA is of importance considering pharmacodynamic monitoring and optimization of MPA treatment.
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Affiliation(s)
- Sara Bremer
- Department of Medical Biochemistry, Rikshospitalet University Hospital, Oslo, Norway
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