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Salazar J, Riera P, Gordillo J, Altès A, Martínez M, Serès M, Llaó J, Giordano A, Garcia-Planella E. Predictive role of ITPA genetic variants in thiopurine-related myelotoxicity in Crohn's disease patients. THE PHARMACOGENOMICS JOURNAL 2024; 24:20. [PMID: 38906864 DOI: 10.1038/s41397-024-00341-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 06/13/2024] [Accepted: 06/17/2024] [Indexed: 06/23/2024]
Abstract
Thiopurines, an effective therapy for Crohn's disease (CD), often lead to adverse events (AEs). Gene polymorphisms affecting thiopurine metabolism may predict AEs. This retrospective study in CD patients (n = 114) with TPMT activity > 5 Units/Red Blood Cells analyzed TPMT (c.238 G > C, c.460 G > A, c.719 A > G), ITPA (c.94 C > A, IVS2 + 21 A > C), and NUDT15 (c.415 C > T) polymorphisms. All patients received azathioprine (median dose 2.2 mg/kg) with 41.2% experiencing AEs, mainly myelotoxicity (28.1%). No NUDT15 polymorphisms were found, 7% had TPMT, and 31.6% had ITPA polymorphisms. AEs led to therapy modifications in 41.2% of patients. Multivariate analysis identified advanced age (OR 1.046, p = 0.007) and ITPA IVS2 + 21 A > C (OR 3.622, p = 0.015) as independent predictors of AEs. IVS2 + 21 A > C was also associated with myelotoxicity (OR 2.863, p = 0.021). These findings suggest that ITPA IVS2 + 21 A > C polymorphism and advanced age predict AEs during thiopurine therapy for CD with intermediate-normal TPMT activity.
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Affiliation(s)
- Juliana Salazar
- Translational Medical Oncology Laboratory, Institut de Recerca Biomèdica Sant Pau (IIB-Sant Pau), Barcelona, Spain
| | - Pau Riera
- Pharmacy Department, Hospital de la Santa Creu I Sant Pau, Barcelona, Spain
- CIBERER U-705, Barcelona, Spain
| | - Jordi Gordillo
- IBD Unit Gastroenterology Department, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
- Institut de Recerca Biomèdica Sant Pau (IIB-Sant Pau), Barcelona, Spain
| | - Albert Altès
- Hematology Department, Fundació Althaia, Manresa, Barcelona, Spain
| | - Miguel Martínez
- IBD Unit Gastroenterology Department, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Montserrat Serès
- Emergency Department, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Jordina Llaó
- IBD Unit Gastroenterology Department, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Antonio Giordano
- IBD Unit Gastroenterology Department, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain.
- Institut de Recerca Biomèdica Sant Pau (IIB-Sant Pau), Barcelona, Spain.
| | - Esther Garcia-Planella
- IBD Unit Gastroenterology Department, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
- Institut de Recerca Biomèdica Sant Pau (IIB-Sant Pau), Barcelona, Spain
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Ribeiro AC, Gerheim PSAS, Chebli JMF, Nascimento JWL, de Faria Pinto P. The Role of Pharmacogenetics in the Therapeutic Response to Thiopurines in the Treatment of Inflammatory Bowel Disease: A Systematic Review. J Clin Med 2023; 12:6742. [PMID: 37959208 PMCID: PMC10649589 DOI: 10.3390/jcm12216742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 09/26/2023] [Accepted: 10/07/2023] [Indexed: 11/15/2023] Open
Abstract
This study focuses on the use of thiopurines for treating inflammatory bowel diseases (IBD). These drugs undergo enzymatic changes within the body, resulting in active and inactive metabolites that influence their therapeutic effects. The research examines the role of genetic polymorphisms in the enzyme thiopurine S-methyltransferase (TPMT) in predicting the therapeutic response and adverse effects of thiopurine treatment. The TPMT genotype variations impact the individual responses to thiopurines. Patients with reduced TPMT activity are more susceptible to adverse reactions (AEs), such leukopenia, hepatotoxicity, pancreatitis, and nausea, which are common adverse effects of thiopurine therapy. The therapeutic monitoring of the metabolites 6-thioguanine nucleotides (6-TGN) and 6-methyl mercaptopurine (6-MMP) is proposed to optimize treatment and minimize AEs. Patients with higher 6-TGN levels tend to have better clinical responses, while elevated 6-MMP levels are linked to hepatotoxicity. Genotyping for TPMT before or during treatment initiation is suggested to tailor dosing strategies and enhance treatment efficacy while reducing the risk of myelosuppression. In conclusion, this study highlights the importance of considering genetic variations and metabolite levels in optimizing thiopurine therapy for IBD patients, focusing on balance therapeutic efficacy with the prevention of adverse effects and contributing to personalized treatment and better patient outcomes.
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Affiliation(s)
- Aline C. Ribeiro
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, Federal University of Juiz de Fora, Juiz de Fora 36036-900, Minas Gerais, Brazil;
| | - Pâmela S. A. S. Gerheim
- Department of Pharmacology, Federal University of Juiz de Fora, Juiz de Fora 36036-900, Minas Gerais, Brazil;
| | - Julio Maria Fonseca Chebli
- Division of Gastroenterology, Department of Internal Medicine, Federal University of Juiz de Fora, Juiz de Fora 36036-900, Minas Gerais, Brazil;
| | - Jorge Willian L. Nascimento
- Laboratory of Clinical and Experimental Pharmacology, Department of Pharmacology, Federal University of Juiz de Fora, Juiz de Fora 36036-900, Minas Gerais, Brazil
| | - Priscila de Faria Pinto
- Department of Biochemistry, Institute of Biological Sciences, Federal University of Juiz de Fora, Juiz de Fora 36036-900, Minas Gerais, Brazil
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Association of ITPA gene polymorphisms with adverse effects of AZA/6-MP administration: a systematic review and meta-analysis. THE PHARMACOGENOMICS JOURNAL 2022; 22:39-54. [PMID: 35034963 DOI: 10.1038/s41397-021-00255-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/24/2021] [Accepted: 09/20/2021] [Indexed: 02/07/2023]
Abstract
Azathioprine (AZA) and its metabolite, mercaptopurine (6-MP), are widely used immunosuppressant drugs. Polymorphisms in genes implicated in AZA/6-MP metabolism, reportedly, could account in part for their potential toxicity. In the present study we performed a systematic review and a meta-analysis, comprising 30 studies and 3582 individuals, to investigate the putative genetic association of two inosine triphosphatase (ITPA) polymorphisms with adverse effects in patients treated with AZA/6-MP. We found that rs1127354 is associated with neutropenia in general populations and in children (OR: 2.39, 95%CI: 1.97-2.90, and OR: 2.43, 95%CI: 2.12-2.79, respectively), and with all adverse effects tested herein in adult populations (OR: 2.12, 95%CI: 1.22-3.69). We also found that rs7270101 is associated with neutropenia and leucopenia in all-ages populations (OR: 2.93, 95%CI: 2.36-3.63, and OR: 2.82, 95%CI: 1.76-4.50, respectively) and with all adverse effects tested herein in children (OR: 1.74, 95%CI: 1.06-2.87). Stratification according to background disease, in combination with multiple comparisons corrections, verified neutropenia to be associated with both polymorphisms, in acute lymphoblastic leukemia (ALL) patients. These findings suggest that ITPA polymorphisms could be used as predictive biomarkers for adverse effects of thiopurine drugs to eliminate intolerance in ALL patients and clarify dosing in patients with different ITPA variants.
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Zamzami MA. Inosine Triphosphate Pyrophosphatase (ITPase): Functions, Mutations, Polymorphisms and Its Impact on Cancer Therapies. Cells 2022; 11:384. [PMID: 35159194 PMCID: PMC8833965 DOI: 10.3390/cells11030384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 11/16/2022] Open
Abstract
Inosine triphosphate pyrophosphatase (ITPase) is an enzyme encoded by the ITPA gene and functions to prevent the incorporation of noncanonical purine nucleotides into DNA and RNA. Specifically, the ITPase catalyzed the hydrolysis of (deoxy) nucleoside triphosphates ((d) NTPs) into the corresponding nucleoside monophosphate with the concomitant release of pyrophosphate. Recently, thiopurine drug metabolites such as azathioprine have been included in the lists of ITPase substrates. Interestingly, inosine or xanthosine triphosphate (ITP/XTP) and their deoxy analogs, deoxy inosine or xanthosine triphosphate (dITP/dXTP), are products of important biological reactions such as deamination that take place within the cellular compartments. However, the incorporation of ITP/XTP, dITP/dXTP, or the genetic deficiency or polymorphism of the ITPA gene have been implicated in many human diseases, including infantile epileptic encephalopathy, early onset of tuberculosis, and the responsiveness of patients to cancer therapy. This review provides an up-to-date report on the ITPase enzyme, including information regarding its discovery, analysis, and cellular localization, its implication in human diseases including cancer, and its therapeutic potential, amongst others.
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Affiliation(s)
- Mazin A. Zamzami
- Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia;
- Centre of Artificial Intelligence in Precision Medicines, King Abdulaziz University, Jeddah 21589, Saudi Arabia
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Deben DS, Wong DR, van Bodegraven AA. Current status and future perspectives on the use of therapeutic drug monitoring of thiopurine metabolites in patients with inflammatory bowel disease. Expert Opin Drug Metab Toxicol 2022; 17:1433-1444. [PMID: 35023443 DOI: 10.1080/17425255.2021.2029406] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Despite new treatment options for inflammatory bowel disease (IBD), conventional thiopurines remain a common treatment option for maintaining remission, particularly in non-Westernized countries. Therapeutic drug monitoring (TDM) is advised in standard care for optimizing therapy strategies to improve effectiveness, reveal nonadherence and reduce toxicity. Still, the rationale of TDM is debated. AREAS COVERED Key insights on TDM of thiopurine metabolites are discussed. The pharmacology of thiopurines is described, emphasizing the interindividual differences in pharmacogenetics, pharmacokinetics and pharmacodynamics. Pharmacological differences between conventional thiopurines and tioguanine are outlined. Finally, several optimization strategies for thiopurine therapy in IBD are discussed. EXPERT OPINION TDM has been a useful, but limited, tool to individualize thiopurine therapy. Pharmacokinetic data on the active thiopurine metabolites, derived from measurements in erythrocytes, associated with clinical response only partially predict effectiveness and toxicity. An additional pharmacodynamic marker, such as Rac1/pSTAT3 expression in leukocytes, may improve applicability of TDM in the future.
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Affiliation(s)
- Debbie S Deben
- Dept. of Clinical Pharmacy, Clinical pharmacology and Toxicology, Zuyderland Medical Centre, Sittard-Geleen/Heerlen, The Netherlands
| | - Dennis R Wong
- Dept. of Clinical Pharmacy, Clinical pharmacology and Toxicology, Zuyderland Medical Centre, Sittard-Geleen/Heerlen, The Netherlands
| | - Adriaan A van Bodegraven
- Dept. of Gastroenterology, Geriatrics, Internal and Intensive Care Medicine (Co-MIK), Zuyderland Medical Centre Sittard-Geleen/Heerlen, The Netherlands.,Dept. of Gastroenterology and Hepatology, Amsterdam, The Netherlands
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Aluko A, Ranganathan P. Pharmacogenetics of Drug Therapies in Rheumatoid Arthritis. Methods Mol Biol 2022; 2547:527-567. [PMID: 36068476 DOI: 10.1007/978-1-0716-2573-6_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Rheumatoid arthritis (RA) is a chronic systemic inflammatory disorder that can lead to severe joint damage and is often associated with a high morbidity and disability. Disease-modifying anti-rheumatic drugs (DMARDs) are the mainstay of treatment in RA. DMARDs not only relieve the clinical signs and symptoms of RA but also inhibit the radiographic progression of disease and reduce the effects of chronic systemic inflammation. Since the introduction of biologic DMARDs in the late 1990s, the therapeutic range of options for the management of RA has significantly expanded. However, patients' response to these agents is not uniform with considerable variability in both efficacy and toxicity. There are no reliable means of predicting an individual patient's response to a given DMARD prior to initiation of therapy. In this chapter, the current published literature on the pharmacogenetics of traditional DMARDS and the newer biologic DMARDs in RA is highlighted. Pharmacogenetics may help individualize drug therapy in patients with RA by providing reliable biomarkers to predict medication toxicity and efficacy.
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Affiliation(s)
- Atinuke Aluko
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Prabha Ranganathan
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA.
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ITPA Activity in Adults and Children Treated With or Without Azathioprine: Relationship Between TPMT Activity, Thiopurine Metabolites, and Co-medications. Ther Drug Monit 2018. [PMID: 28650902 DOI: 10.1097/ftd.0000000000000430] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The implication of inosine triphosphate pyrophosphatase (ITPA) on thiopurine drug response variability has been investigated but little data are available on its role on thiopurine metabolites. The ability of ITPA to modify the thiopurine metabolite levels is currently used to optimize azathioprine (AZA) therapy in relation to thiopurine S-methyltransferase (TPMT) activity, the aim of this study is to investigate ITPA phenotype in a large population and to evaluate the relation between ITPA and TPMT activities and thiopurine metabolites. METHODS ITPA activity was determined in 183 adults and 138 children with or without AZA therapy. 6-thioguanine nucleotides (6-TGN), 6-methylmercaptopurine nucleotides (6-MeMPN) levels, and ITPA as well as TPMT activities were measured in red blood cells. Using the Gaussian mixture model, distribution of ITPA activity was evaluated. Intraindividual variability and influence of age, sex, AZA treatment and associated co-medications on ITPA activity were also assessed. RESULTS This retrospective study shows a quadrimodal distribution in ITPA activity. No influence of age, sex, AZA therapy, and co-medications was found. In adults, ITPA activity was not significantly associated with 6-TGN or 6-MeMPN concentrations, whereas a weak negative correlation was observed with 6-MeMPN levels in pediatric populations (rs = -0.261; P = 0.024). A weak positive correlation was observed between ITPA and TPMT activities in children (rs = 0.289; P = 0.001). CONCLUSIONS ITPA activity was poorly influenced by nongenetic parameters and has no influence on 6-TGN and 6-MeMPN concentrations in adults and only a weak correlation with 6-MeMPN and TPMT activity in children. These results demonstrate that ITPA is not a rate-limiting enzyme in the formation of 6-TGN but suggest that a decrease in ITPA activity in children may be a risk factor for accumulation of 6-MeMPN in cells.
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Gene dosage effects in yeast support broader roles for the LOG1, HAM1 and DUT1 genes in detoxification of nucleotide analogues. PLoS One 2018; 13:e0196840. [PMID: 29738539 PMCID: PMC5940212 DOI: 10.1371/journal.pone.0196840] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 04/21/2018] [Indexed: 12/22/2022] Open
Abstract
Purine and pyrimidine analogues have important uses in chemotherapies against cancer, and a better understanding of the mechanisms that cause resistance to these drugs is therefore of importance in cancer treatment. In the yeast Saccharomyces cerevisiae, overexpression of the HAM1 gene encoding inosine triphosphate pyrophosphatase confers resistance to both the purine analogue 6-N-hydroxylaminopurine (HAP) and the pyrimidine analogue 5-fluorouracil (5-FU) (Carlsson et al., 2013, PLoS One 8, e52094). To find out more about the mechanisms of resistance to nucleotide analogues, and possible interdependencies between purine and pyrimidine analogue resistance mechanisms, we screened a plasmid library in yeast for genes that confer HAP resistance when overexpressed. We cloned four such genes: ADE4, DUT1, APT2, and ATR1. We further looked for genetic interactions between these genes and genes previously found to confer resistance to 5-FU. We found that HMS1, LOG1 (YJL055W), HAM1, and ATR1 confer resistance to both 5-FU and HAP, whereas ADE4, DUT1 and APT2 are specific for HAP resistance, and CPA1 and CPA2 specific for 5-FU resistance. Possible mechanisms for 5-FU and HAP detoxification are discussed based on the observed genetic interactions. Based on the effect of LOG1 against both 5-FU and HAP toxicity, we propose that the original function of the LOG (LONELY GUY) family of proteins likely was to degrade non-canonical nucleotides, and that their role in cytokinin production is a later development in some organisms.
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Citterio-Quentin A, Moulsma M, Gustin MP, Lachaux A, Boulieu R. ITPA Activity in Children Treated by Azathioprine: Relationship to the Occurrence of Adverse Drug Reactions and Inflammatory Response. Basic Clin Pharmacol Toxicol 2018; 122:588-595. [PMID: 29327413 DOI: 10.1111/bcpt.12958] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 12/27/2017] [Indexed: 12/13/2022]
Abstract
Azathioprine (AZA), a thiopurine drug, is widely used in the treatment of children with immunological diseases such as inflammatory bowel disease (IBD) and autoimmune hepatitis (AIH); however, interindividual variability in the occurrence of adverse drug reactions (ADRs) and drug response is observed. This study investigated (i) the relationships between inosine triphosphate pyrophosphatase (ITPA) activity, an enzyme involved in thiopurine metabolism, and the occurrence of ADRs in children with immunological disease on AZA therapy, and (ii) the relationship between ITPA activity and the inflammatory activity observed in children with IBD. ITPA and TPMT activities were determined in 106 children with immunological disease on AZA therapy. Markers of hepatotoxicity, myelotoxicity, pancreatitis and inflammation as well as clinical information were retrospectively collected during regular medical visits. No significant association was found between ITPA activity and hepatotoxicity or clinical ADRs such as cutaneous reactions, arthralgia, flulike symptoms and gastrointestinal disorders. Concerning myelotoxicity, a significant relation was observed between ITPA activity and RBC mean corpuscular volume (MCV; p=0.003). This observation may be related to the significant relationship found between high ITPA activity and the increase in γ-globulin level reflecting inflammation (p=0.005). In our study, ITPA activity was not associated with occurrence of ADRs, but a relationship between high ITPA activity and γ-globulin, a marker of inflammation, was found in children with IBD. Therefore, measurement of ITPA activity may help to identify children with IBD predisposed to residual inflammation on AZA therapy. Further prospective studies are needed to confirm this result.
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Affiliation(s)
- Antony Citterio-Quentin
- UMR CNRS 5305, Clinical Pharmacy, Pharmacokinetics and Drug Evaluation, Université de Lyon, Université Lyon 1, Lyon, France.,Edouard Herriot Hospital, Laboratory of Medical Biology Multi Sites of the University Hospital of Lyon, Pharmaco-Toxicology Unit, Civil Hospices of Lyon, Lyon, France
| | - Mustapha Moulsma
- Edouard Herriot Hospital, Laboratory of Medical Biology Multi Sites of the University Hospital of Lyon, Pharmaco-Toxicology Unit, Civil Hospices of Lyon, Lyon, France
| | - Marie-Paule Gustin
- Emerging pathogen Laboratory - Fondation Mérieux, Centre International de Recherche en Infectiologie (CIRI), Inserm U1111, CNRS UMR5308, ENS de Lyon, UCBL1, Lyon, France
| | - Alain Lachaux
- Pediatric Gastroenterology Unit, Civil Hospices of Lyon, Hôpital Femme-Mère-Enfant (HFME), Lyon, France
| | - Roselyne Boulieu
- UMR CNRS 5305, Clinical Pharmacy, Pharmacokinetics and Drug Evaluation, Université de Lyon, Université Lyon 1, Lyon, France.,Edouard Herriot Hospital, Laboratory of Medical Biology Multi Sites of the University Hospital of Lyon, Pharmaco-Toxicology Unit, Civil Hospices of Lyon, Lyon, France
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10
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Adam L, Phulukdaree A, Soma P. Effective long-term solution to therapeutic remission in Inflammatory Bowel Disease: Role of Azathioprine. Biomed Pharmacother 2018; 100:8-14. [PMID: 29421584 DOI: 10.1016/j.biopha.2018.01.152] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 01/26/2018] [Accepted: 01/29/2018] [Indexed: 12/18/2022] Open
Abstract
Azathioprine (AZA) is a well-known immunosuppressant used for many years for its ability to ensure long term disease remission in inflammatory bowel diseases (IBD) at an affordable cost to the public. However, the side effect profile has raised many concerns with numerous investigations into the risk, cause and prevention of these effects. Much of the side effect profile of AZA can be linked to a single nucleotide polymorphism (SNP) in the thiopurine methyltransferase (TPMT) gene which ensures the breakdown and efficacy of AZA. Mutated TPMT alleles result in low or deficient TPMT levels which directly correlate to cytotoxity. This is a review of the role of AZA in the treatment of IBD. Knowing a patient's TPMT status allows the prescribing doctor to make an informed decision about dosage and be more alert to the signs of cytotoxicity. It is essential to include "early warning" SNP testing into common practice to ensure therapeutic efficacy.
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Affiliation(s)
- Lyla Adam
- University of Pretoria, Faculty of Health Sciences, School of Medicine, Department of Pharmacology, South Africa.
| | - Alisa Phulukdaree
- University of Pretoria, Faculty of Health Sciences, School of Medicine, Department of Physiology, South Africa.
| | - Prashilla Soma
- University of Pretoria, Faculty of Health Sciences, School of Medicine, Department of Physiology, South Africa.
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Rufini S, Ciccacci C, Novelli G, Borgiani P. Pharmacogenetics of inflammatory bowel disease: a focus on Crohn's disease. Pharmacogenomics 2017; 18:1095-1114. [PMID: 28686143 DOI: 10.2217/pgs-2017-0068] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Crohn's disease is an inflammatory bowel disease showing a high heterogeneity in phenotype and a strong genetic component. The treatment is complex, due to different severity of clinical parameters and to the fact that therapies only permit to control symptoms and to induce remission for short periods. Moreover, all categories of drugs present a great interindividual variability both in terms of efficacy and side effects appearance. For this reason, the identification of specific genomic biomarkers involved in drugs response will be of great clinical utility in order to foresee drug's efficacy and to prevent adverse reactions, permitting a more personalized therapeutic approach. In this review, we focus the attention on the pharmacogenetic studies regarding drugs commonly utilized in Crohn's disease treatment.
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Affiliation(s)
- Sara Rufini
- Department of Biomedicine & Prevention, Genetics Unit, University of Rome "Tor Vergata", Rome, Italy
| | - Cinzia Ciccacci
- Department of Biomedicine & Prevention, Genetics Unit, University of Rome "Tor Vergata", Rome, Italy
| | - Giuseppe Novelli
- Department of Biomedicine & Prevention, Genetics Unit, University of Rome "Tor Vergata", Rome, Italy
| | - Paola Borgiani
- Department of Biomedicine & Prevention, Genetics Unit, University of Rome "Tor Vergata", Rome, Italy
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12
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Burgis NE. A disease spectrum for ITPA variation: advances in biochemical and clinical research. J Biomed Sci 2016; 23:73. [PMID: 27770805 PMCID: PMC5075207 DOI: 10.1186/s12929-016-0291-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 10/19/2016] [Indexed: 12/15/2022] Open
Abstract
Human ITPase (encoded by the ITPA gene) is a protective enzyme which acts to exclude noncanonical (deoxy)nucleoside triphosphates ((d)NTPs) such as (deoxy)inosine 5′-triphosphate ((d)ITP), from (d)NTP pools. Until the last few years, the importance of ITPase in human health and disease has been enigmatic. In 2009, an article was published demonstrating that ITPase deficiency in mice is lethal. All homozygous null offspring died before weaning as a result of cardiomyopathy due to a defect in the maintenance of quality ATP pools. More recently, a whole exome sequencing project revealed that very rare, severe human ITPA mutation results in early infantile encephalopathy and death. It has been estimated that nearly one third of the human population has an ITPA status which is associated with decreased ITPase activity. ITPA status has been linked to altered outcomes for patients undergoing thiopurine or ribavirin therapy. Thiopurine therapy can be toxic for patients with ITPA polymorphism, however, ITPA polymorphism is associated with improved outcomes for patients undergoing ribavirin treatment. ITPA polymorphism has also been linked to early-onset tuberculosis susceptibility. These data suggest a spectrum of ITPA-related disease exists in human populations. Potentially, ITPA status may affect a large number of patient outcomes, suggesting that modulation of ITPase activity is an important emerging avenue for reducing the number of negative outcomes for ITPA-related disease. Recent biochemical studies have aimed to provide rationale for clinical observations, better understand substrate selectivity and provide a platform for modulation of ITPase activity.
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Affiliation(s)
- Nicholas E Burgis
- Department of Chemistry and Biochemistry, Eastern Washington University, 226 Science Building, Cheney, WA, 99004, USA.
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13
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Skrzypczak-Zielinska M, Borun P, Bartkowiak-Kaczmarek A, Zakerska-Banaszak O, Walczak M, Dobrowolska A, Kurzawski M, Waszak M, Lipinski D, Plawski A, Slomski R. A Simple Method for TPMT and ITPA Genotyping Using Multiplex HRMA for Patients Treated with Thiopurine Drugs. Mol Diagn Ther 2016; 20:493-9. [PMID: 27307154 PMCID: PMC5021755 DOI: 10.1007/s40291-016-0217-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Thiopurine methyltransferase (TPMT) and inosine triphosphatase (ITPA) are crucial enzymes involved in the metabolism of thiopurine drugs: azathioprine and 6-mercaptopurine, used in the treatment of leukemia or inflammatory bowel diseases (IBD). The activity in these enzymes correlates with the genetic polymorphism of the TPMT and ITPA genes, respectively, which determines an individual reaction and dosing of thiopurines. Three main TPMT alleles: TPMT*2 (c.238G>C), TPMT*3A (c.460G>A, c.719A>G) and TPMT*3C (c.719A>G) account for 80-95 % of inherited TPMT deficiency in different populations in the world. In the ITPA gene, a c.94C>A mutation is significantly associated with an adverse thiopurine reaction. The aim of this study was to develop a quick and highly sensitive method for determining major TPMT and ITPA alleles. Here we present the molecular test for genotyping c.238G>C, c.460G>A, c.719A>G and c.94C>A changes based on multiplex high resolution melting analysis (HRMA). We analyzed DNA samples from 100 clinically diagnosed IBD patients treated with thiopurine drugs, and a known genotype in the positions 238, 460 and 719 of the TPMT gene as well as in position 94 of the ITPA gene. Our results obtained with multiplex HRMA indicated 100 % accuracy in comparison with data from restriction fragments length polymorphism (RFLP) and standard DNA sequencing. We conclude, that multiplex HRMA can be used as a quick, sensitive and efficient alternative diagnostic method compared to conventional techniques for the determination of TPMT*2, TPMT*3A and TPMT*3C alleles and c.94C>A change in the ITPA gene.
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Affiliation(s)
| | - Pawel Borun
- Institute of Human Genetics, Polish Academy of Sciences, ul. Strzeszynska 32, 60-479, Poznan, Poland
| | - Anna Bartkowiak-Kaczmarek
- Laboratory of Cell Biophysics, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Oliwia Zakerska-Banaszak
- Institute of Human Genetics, Polish Academy of Sciences, ul. Strzeszynska 32, 60-479, Poznan, Poland
| | - Michal Walczak
- Institute of Human Genetics, Polish Academy of Sciences, ul. Strzeszynska 32, 60-479, Poznan, Poland
| | - Agnieszka Dobrowolska
- Department of Gastroenterology, Human Nutrition and Internal Diseases, University of Medical Sciences, Poznan, Poland
| | - Mateusz Kurzawski
- Department of Experimental and Clinical Pharmacology, Pomeranian Medical University, Szczecin, Poland
| | - Malgorzata Waszak
- Department of Functional Anatomy, University School of Physical Education, Poznan, Poland
| | - Daniel Lipinski
- Department of Biochemistry and Biotechnology, University of Life Sciences, Poznan, Poland
| | - Andrzej Plawski
- Institute of Human Genetics, Polish Academy of Sciences, ul. Strzeszynska 32, 60-479, Poznan, Poland
| | - Ryszard Slomski
- Institute of Human Genetics, Polish Academy of Sciences, ul. Strzeszynska 32, 60-479, Poznan, Poland
- Department of Biochemistry and Biotechnology, University of Life Sciences, Poznan, Poland
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14
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Zur RM, Roy LM, Ito S, Beyene J, Carew C, Ungar WJ. Thiopurine S-methyltransferase testing for averting drug toxicity: a meta-analysis of diagnostic test accuracy. THE PHARMACOGENOMICS JOURNAL 2016; 16:305-11. [PMID: 27217052 PMCID: PMC4957983 DOI: 10.1038/tpj.2016.37] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 04/15/2016] [Indexed: 01/12/2023]
Abstract
Thiopurine S-methyltransferase (TPMT) deficiency increases the risk of serious adverse events in persons receiving thiopurines. The objective was to synthesize reported sensitivity and specificity of TPMT phenotyping and genotyping using a latent class hierarchical summary receiver operating characteristic meta-analysis. In 27 studies, pooled sensitivity and specificity of phenotyping for deficient individuals was 75.9% (95% credible interval (CrI), 58.3-87.0%) and 98.9% (96.3-100%), respectively. For genotype tests evaluating TPMT*2 and TPMT*3, sensitivity and specificity was 90.4% (79.1-99.4%) and 100.0% (99.9-100%), respectively. For individuals with deficient or intermediate activity, phenotype sensitivity and specificity was 91.3% (86.4-95.5%) and 92.6% (86.5-96.6%), respectively. For genotype tests evaluating TPMT*2 and TPMT*3, sensitivity and specificity was 88.9% (81.6-97.5%) and 99.2% (98.4-99.9%), respectively. Genotyping has higher sensitivity as long as TPMT*2 and TPMT*3 are tested. Both approaches display high specificity. Latent class meta-analysis is a useful method for synthesizing diagnostic test performance data for clinical practice guidelines.The Pharmacogenomics Journal advance online publication, 24 May 2016; doi:10.1038/tpj.2016.37.
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Affiliation(s)
- RM Zur
- Child Health Evaluative Sciences, The Hospital for Sick Children Research Institute, Peter Gilgan Centre for Research and Learning, Toronto, Canada
| | - LM Roy
- Child Health Evaluative Sciences, The Hospital for Sick Children Research Institute, Peter Gilgan Centre for Research and Learning, Toronto, Canada
| | - S Ito
- Division of Clinical Pharmacology and Toxicology, The Hospital for Sick Children, Toronto, Canada
- Departments of Pharmacology & Pharmacy, Faculty of Medicine, Department of Paediatrics, University of Toronto, Toronto, Canada
| | - J Beyene
- Department of Clinical Epidemiology & Biostatistics, McMaster University, Hamilton, Canada
| | - C Carew
- Centre for Genetic Medicine, The Hospital for Sick Children, Toronto, Canada
| | - WJ Ungar
- Child Health Evaluative Sciences, The Hospital for Sick Children Research Institute, Peter Gilgan Centre for Research and Learning, Toronto, Canada
- Institute for Health Policy, Management & Evaluation, University of Toronto, Toronto, Canada
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Roy LM, Zur RM, Uleryk E, Carew C, Ito S, Ungar WJ. Thiopurine S-methyltransferase testing for averting drug toxicity in patients receiving thiopurines: a systematic review. Pharmacogenomics 2016; 17:633-56. [PMID: 27020704 PMCID: PMC4931919 DOI: 10.2217/pgs.16.12] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
AIM Thiopurine S-methyltransferase (TPMT) testing is used in patients receiving thiopurines to identify enzyme deficiencies and risk for adverse drug reactions. It is uncertain whether genotyping is superior to phenotyping. The objectives were to conduct a systematic review of TPMT-test performance studies. MATERIALS & METHODS Electronic and grey literature sources were searched for studies reporting test performance compared with a reference standard. Sixty-six eligible studies were appraised for quality. RESULTS Thirty phenotype-genotype and six phenotype-phenotype comparisons were of high quality. The calculated sensitivity and specificity for genotyping to identify a homozygous mutation ranged from 0.0-100.0% and from 97.8-100.0%, respectively. CONCLUSION Clinical decision-makers require high-quality evidence of clinical validity and clinical utility of TPMT genotyping to ensure appropriate use in patients.
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Affiliation(s)
- Lilla M Roy
- Child Health Evaluative Sciences, The Hospital for Sick Children Research Institute, Toronto, Canada
| | - Richard M Zur
- Child Health Evaluative Sciences, The Hospital for Sick Children Research Institute, Toronto, Canada
| | - Elizabeth Uleryk
- Library Services, The Hospital for Sick Children, Toronto, Canada
| | - Chris Carew
- Centre for Genetic Medicine, The Hospital for Sick Children, Toronto, Canada
| | - Shinya Ito
- Division of Clinical Pharmacology & Toxicology, The Hospital for Sick Children, Toronto, Canada
- Departments of Pharmacology & Pharmacy, Faculty of Medicine Department of Paediatrics, University of Toronto, Canada
| | - Wendy J Ungar
- Child Health Evaluative Sciences, The Hospital for Sick Children Research Institute, Toronto, Canada
- Institute for Health Policy, Management & Evaluation, University of Toronto, Canada
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16
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Steponaitiene R, Kupcinskas J, Survilaite S, Varkalaite G, Jonaitis L, Kiudelis G, Denapiene G, Valantinas J, Skieceviciene J, Kupcinskas L. TPMT and ITPA genetic variants in Lithuanian inflammatory bowel disease patients: Prevalence and azathioprine-related side effects. Adv Med Sci 2016; 61:135-40. [PMID: 26674571 DOI: 10.1016/j.advms.2015.09.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 09/09/2015] [Accepted: 09/29/2015] [Indexed: 12/20/2022]
Abstract
PURPOSE Inter-individual thiopurine metabolism variability can influence treatment outcomes in inflammatory bowel disease (IBD) patients. Genetic polymorphisms in thiopurine methyltransferase (TPMT) and inosine triphosphate pyrophosphatase (ITPA) were linked with toxicity of azathioprine (AZA). The aim of the study was to investigate frequencies of TPMT and ITPA polymorphisms in Lithuanian IBD patients and analyze their association with AZA-related adverse events. MATERIALS/METHODS Polymorphisms in TPMT (TPMT*2,*3B,*3C,*3A) and ITPA (rs1127354, rs7270101) genes were determined using PCR-RFLP and TaqMan(®) genotyping assays. 551 consecutive Lithuanian IBD patients were genotyped. The use of AZA and its side effects were assessed retrospectively according to hospital medical records. RESULTS Frequencies of TPMT*3A, TPMT*3B and TPMT*3C alleles were 3.1%, 0.5% and 0.1%, respectively. TPMT*2 genetic variant was not detected in the study group. The distribution of minor alleles for ITPA rs1127354 and rs7270101 polymorphisms was 9.9% and 10.5%, respectively. AZA was prescribed in 82 patients and it provoked myelotoxicity in 11%, hepatotoxicity in 6.1%, dyspepsia in 6.1%, and pancreatitis in 3.6% of cases. Among patients who had AZA-related myelotoxicity, 11.1% were TPMT compound heterozygous, 44.4% had heterozygous genotype (P<0.01). Frequencies of ITPA minor alleles were similar among the patients with and without AZA-related side effects. CONCLUSION Frequencies of TPMT and ITPA variant alleles in Lithuanian IBD group were similar to those observed in the Northern-Eastern Europe Caucasian populations. Polymorphisms in TPMT might be associated with myelotoxicity and leukopenia in AZA treated patients, while ITPA variant alleles appear not to be linked with treatment-related side effects.
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Affiliation(s)
- Ruta Steponaitiene
- Institute for Digestive Research, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Juozas Kupcinskas
- Institute for Digestive Research, Lithuanian University of Health Sciences, Kaunas, Lithuania; Department of Gastroenterology, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Santa Survilaite
- Institute for Digestive Research, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Greta Varkalaite
- Institute for Digestive Research, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Laimas Jonaitis
- Institute for Digestive Research, Lithuanian University of Health Sciences, Kaunas, Lithuania; Department of Gastroenterology, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Gediminas Kiudelis
- Institute for Digestive Research, Lithuanian University of Health Sciences, Kaunas, Lithuania; Department of Gastroenterology, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Goda Denapiene
- Clinic of Gastroenterology, Nephrourology and Surgery, Medical Faculty of Vilnius University, Vilnius University, Vilnius, Lithuania
| | - Jonas Valantinas
- Clinic of Gastroenterology, Nephrourology and Surgery, Medical Faculty of Vilnius University, Vilnius University, Vilnius, Lithuania
| | - Jurgita Skieceviciene
- Institute for Digestive Research, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Limas Kupcinskas
- Institute for Digestive Research, Lithuanian University of Health Sciences, Kaunas, Lithuania; Department of Gastroenterology, Lithuanian University of Health Sciences, Kaunas, Lithuania.
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17
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Awdishu L, Joy MS. Role of Pharmacogenomics in Kidney Disease and Injury. Adv Chronic Kidney Dis 2016; 23:106-19. [PMID: 26979149 DOI: 10.1053/j.ackd.2016.01.018] [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] [Received: 11/23/2015] [Revised: 01/28/2016] [Accepted: 01/31/2016] [Indexed: 12/29/2022]
Abstract
There has been considerable excitement in the kidney community surrounding the research findings on the genetic contributions to kidney diseases. However, positive outcomes of personalized therapeutic interventions can be circumvented by unpredictable pharmacokinetics of prescribed drugs. Furthermore, unpredictable drug disposition can result in toxicities such as kidney injury. Patient covariates, disease covariates, and pharmacogenetics all contribute to variability in drug disposition. Further treatment personalization and avoidance of drug- and biologic- induced kidney injury will require extensive knowledge and expertise in renal clinical pharmacology. The current review will focus on the pharmacogenetics of drugs and biologics used in the treatment of glomerular kidney diseases and drugs implicated in inducing kidney injury phenotypes.
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Gómez-Gómez GJ, Masedo &A, Yela C, Martínez-Montiel MDP, Casís B. Current stage in inflammatory bowel disease: What is next? World J Gastroenterol 2015; 21:11282-11303. [PMID: 26525013 PMCID: PMC4616205 DOI: 10.3748/wjg.v21.i40.11282] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 07/12/2015] [Accepted: 09/02/2015] [Indexed: 02/06/2023] Open
Abstract
In recent years, the incidence of inflammatory bowel disease (IBD) has been on the rise, extending to countries where it was infrequent in the past. As a result, the gap between high and low incidence countries is decreasing. The disease, therefore, has an important economic impact on the healthcare system. Advances in recent years in pharmacogenetics and clinical pharmacology have allowed for the development of treatment strategies adjusted to the patient profile. Concurrently, new drugs aimed at inflammatory targets have been developed that may expand future treatment options. This review examines advances in the optimization of existing drug treatments and the development of novel treatment options for IBD.
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19
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Fong SCM, Blaker PA, Arenas-Hernandez M, Marinaki AM, Sanderson JD. Getting the best out of thiopurine therapy: thiopurine S-methyltransferase and beyond. Biomark Med 2015; 9:51-65. [PMID: 25605455 DOI: 10.2217/bmm.14.97] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Thiopurines are the cornerstone of treatment for a wide variety of medical disorders, ranging from pediatric leukemia to inflammatory bowel disease. Because of their complex metabolism and potential toxicities, the use of biomarkers to predict risk and response is paramount. Thiopurine S-methyltransferase and thiopurine metabolite levels have emerged as companion diagnostics with crucial roles in facilitating safe and effective treatment. This review serves to update the reader on how these tools are being developed and implemented in clinical practice. A useful paradigm in thiopurine therapeutic strategy is presented, along with fresh insights into the mechanisms underlying these approaches. We elaborate on potential future developments in the optimization of thiopurine therapy.
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20
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Roberts RL, Barclay ML. Update on thiopurine pharmacogenetics in inflammatory bowel disease. Pharmacogenomics 2015; 16:891-903. [PMID: 26067482 DOI: 10.2217/pgs.15.29] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Azathioprine and 6-mercaptopurine remain pivotal therapies for the maintenance of disease remission in patients with Crohn's disease and ulcerative colitis. While thiopurine S-methyltransferase deficiency was the first pharmacogenetic phenomenon to be recognized to influence thiopurine toxicity and reliably predict leukopenia, it does not predict other adverse effects, nor does it explain most cases of thiopurine resistance. In recent years, a number of other genetic polymorphisms have received increasing attention in the literature. In particular, SNPs in NUDT15 and in the class II HLA locus have been shown to predict thiopurine-related leukopenia and pancreatitis. The aim of this review is to provide a concise update of genetic variability which may influence patient response to azathioprine and 6-mercaptopurine.
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Affiliation(s)
- Rebecca L Roberts
- Department of Surgical Sciences, Dunedin School of Medicine, PO Box 56, Dunedin, New Zealand
| | - Murray L Barclay
- Department of Medicine, University of Otago Christchurch, PO Box 4345, Christchurch, New Zealand.,Department of Gastroenterology, Christchurch Hospital, Private Bag 4710, Christchurch, New Zealand
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21
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Abstract
The prodrug azathioprine is primarily used for maintaining remission in inflammatory bowel disease, but approximately 30% of the patients suffer adverse side effects. The prodrug is activated by glutathione conjugation and release of 6-mercaptopurine, a reaction most efficiently catalyzed by glutathione transferase (GST) A2-2. Among five genotypes of GST A2-2, the variant A2*E has threefold-fourfold higher catalytic efficiency with azathioprine, suggesting that the expression of A2*E could boost 6-mercaptopurine release and adverse side effects in treated patients. Structure-activity studies of the GST A2-2 variants and homologous alpha class GSTs were made to delineate the determinants of high catalytic efficiency compared to other alpha class GSTs. Engineered chimeras identified GST peptide segments of importance, and replacing the corresponding regions in low-activity GSTs by these short segments produced chimeras with higher azathioprine activity. By contrast, H-site mutagenesis led to decreased azathioprine activity when active-site positions 208 and 213 in these favored segments were mutagenized. Alternative substitutions indicated that hydrophobic residues were favored. A pertinent question is whether variant A2*E represents the highest azathioprine activity achievable within the GST structural framework. This issue was addressed by mutagenesis of H-site residues assumed to interact with the substrate based on molecular modeling. The mutants with notably enhanced activities had small or polar residues in the mutated positions. The most active mutant L107G/L108D/F222H displayed a 70-fold enhanced catalytic efficiency with azathioprine. The determination of its structure by X-ray crystallography showed an expanded H-site, suggesting improved accommodation of the transition state for catalysis.
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Affiliation(s)
- Olof Modén
- Department of Chemistry-BMC, Uppsala University, Uppsala, Sweden
| | - Bengt Mannervik
- Department of Chemistry-BMC, Uppsala University, Uppsala, Sweden; Department of Neurochemistry, Stockholm University, Stockholm, Sweden.
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22
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Determination of Inosine Triphosphate Pyrophosphatase in Red Blood Cells Using HPLC. Ther Drug Monit 2014; 36:689-91. [DOI: 10.1097/ftd.0000000000000075] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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23
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Trinks J, Hulaniuk ML, Caputo M, Pratx LB, Ré V, Fortuny L, Pontoriero A, Frías A, Torres O, Nuñez F, Gadano A, Corach D, Flichman D. Distribution of genetic polymorphisms associated with hepatitis C virus (HCV) antiviral response in a multiethnic and admixed population. THE PHARMACOGENOMICS JOURNAL 2014; 14:549-54. [PMID: 24841973 DOI: 10.1038/tpj.2014.20] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Revised: 03/08/2014] [Accepted: 03/26/2014] [Indexed: 12/19/2022]
Abstract
The prevalence of genetic polymorphisms identified as predictors of therapeutic-induced hepatitis C virus (HCV) clearance differs among ethnic groups. However, there is a paucity of information about their prevalence in South American populations, whose genetic background is highly admixed. Hence, single-nucleotide polymorphisms rs12979860, rs1127354 and rs7270101 were characterized in 1350 healthy individuals, and ethnicity was assessed in 259 randomly selected samples. The frequency of rs12979860CC, associated to HCV treatment response, and rs1127354nonCC, related to protection against hemolytic anemia, were significantly higher among individuals with maternal and paternal Non-native American haplogroups (64.5% and 24.2%), intermediate among admixed samples (44.1% and 20.4%) and the lowest for individuals with Native American ancestry (30.4% and 6.5%). This is the first systematic study focused on analyzing HCV predictors of antiviral response and ethnicity in South American populations. The characterization of these variants is critical to evaluate the risk-benefit of antiviral treatment according to the patient ancestry in admixed populations.
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Affiliation(s)
- J Trinks
- 1] Instituto de Ciencias Básicas y Medicina Experimental (ICBME), Hospital Italiano de Buenos Aires, Buenos Aires, Argentina [2] National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
| | - M L Hulaniuk
- Instituto de Ciencias Básicas y Medicina Experimental (ICBME), Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
| | - M Caputo
- 1] Servicio de Huellas Digitales Genéticas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina [2] National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
| | - L Burgos Pratx
- Servicio de Medicina Transfusional, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
| | - V Ré
- 1] Instituto de Virología Dr José María Vanella, Facultad de Ciencias Médicas de la Universidad Nacional de Córdoba, Córdoba, Argentina [2] National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
| | - L Fortuny
- Servicio de Medicina Transfusional, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
| | - A Pontoriero
- Instituto de Ciencias Básicas y Medicina Experimental (ICBME), Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
| | - A Frías
- Servicio de Medicina Transfusional, Hospital Materno Infantil 'Ramón Sardá', Buenos Aires, Argentina
| | - O Torres
- Servicio de Medicina Transfusional, Hospital Materno Infantil 'Ramón Sardá', Buenos Aires, Argentina
| | - F Nuñez
- Servicio de Medicina Transfusional, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
| | - A Gadano
- Servicio de Hepatología, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
| | - D Corach
- 1] Servicio de Huellas Digitales Genéticas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina [2] National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
| | - D Flichman
- 1] Cátedra de Virología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina [2] National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
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Abstract
Rheumatoid arthritis (RA) is a systemic inflammatory arthritis leading to severe joint damage and associated with high morbidity and mortality. Disease-modifying antirheumatic drugs (DMARDs) are the mainstay of treatment in RA. DMARDs not only relieve the clinical signs and symptoms of RA but also inhibit the radiographic progression of disease. In the last decade, a new class of disease-modifying medications, the biologic agents, has been added to the existing spectrum of DMARDs in RA. However, patients' response to these agents is not uniform with considerable variability in both efficacy and toxicity. There are no reliable means of predicting an individual patient's response to a given DMARD prior to initiation of therapy. In this chapter, the current published literature on the pharmacogenetics of traditional DMARDS and the newer biologic DMARDs in RA is highlighted. Pharmacogenetics may help individualize drug therapy in patients with RA in the near future.
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Affiliation(s)
- Deepali Sen
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, 660 S. Euclid Avenue, Campus Box 8045, St. Louis, MO, 63110, USA
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Simone PD, Pavlov YI, Borgstahl GEO. ITPA (inosine triphosphate pyrophosphatase): from surveillance of nucleotide pools to human disease and pharmacogenetics. Mutat Res 2013; 753:131-146. [PMID: 23969025 DOI: 10.1016/j.mrrev.2013.08.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 07/31/2013] [Accepted: 08/02/2013] [Indexed: 01/08/2023]
Abstract
Cellular nucleotide pools are often contaminated by base analog nucleotides which interfere with a plethora of biological reactions, from DNA and RNA synthesis to cellular signaling. An evolutionarily conserved inosine triphosphate pyrophosphatase (ITPA) removes the non-canonical purine (d)NTPs inosine triphosphate and xanthosine triphosphate by hydrolyzing them into their monophosphate form and pyrophosphate. Mutations in the ITPA orthologs in model organisms lead to genetic instability and, in mice, to severe developmental anomalies. In humans there is genetic polymorphism in ITPA. One allele leads to a proline to threonine substitution at amino acid 32 and causes varying degrees of ITPA deficiency in tissues and plays a role in patients' response to drugs. Structural analysis of this mutant protein reveals that the protein is destabilized by the formation of a cavity in its hydrophobic core. The Pro32Thr allele is thought to cause the observed dominant negative effect because the resulting active enzyme monomer targets both homo- and heterodimers to degradation.
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Affiliation(s)
- Peter D Simone
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Youri I Pavlov
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA; Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, USA; Department of Pathology and Microbiology, University of Nebraska Medical Center, USA; Department of Genetics, St-Petersburg University, St-Petersburg, 199034, Russia
| | - Gloria E O Borgstahl
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA; Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, USA; Department of Pharmaceutical Sciences, University of Nebraska Medical Center, USA.
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Smith M, Blaker P, Patel C, Marinaki A, Arenas M, Escuredo E, Anderson S, Irving P, Sanderson J. The impact of introducing thioguanine nucleotide monitoring into an inflammatory bowel disease clinic. Int J Clin Pract 2013; 67:161-9. [PMID: 23253089 DOI: 10.1111/ijcp.12039] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Thioguanine nucleotides (TGNs) are the active product of thiopurine metabolism. Levels have been correlated with effective clinical response. Nonetheless, the value of TGN monitoring in clinical practice is debated. We report the influence of introducing TGN monitoring into a large adult inflammatory bowel disease (IBD) clinic. PATIENTS AND METHODS Patients with IBD undergoing TGN monitoring were identified from Purine Research Laboratory records. Whole blood TGNs and methylated mercaptopurine nucleotides were hydrolysed to the base and measured using HPLC. Clinical and laboratory data were obtained retrospectively. RESULTS One hundred and eighty-nine patients with 608 available TGN results were identified. In non-responders, TGNs directed treatment change in 39/53 patients. When treatment was changed as directed by TGN, 18/20 (90%) improved vs. 7/21 (33%) where the treatment decision was not TGN-directed, p < 0.001. Where treatment change was directed at optimisation of thiopurine therapy, 14/20 achieved steroid-free remission at 6 months vs. 3/10 where the TGN was ignored, (p = 0.037). Six per cent of patients were non-adherent, 25% under-dosed and 29% over-dosed by TGN. Twelve per cent of patients predominantly methylated thiopurines, this group had low TGN levels and high risk of hepatotoxicity. In responders, adherence and dosing issues were identified and TGN-guided dose-reduction was possible without precipitating relapse. Mean cell volume (MCV), white blood cell count (WBC) and lymphocyte counts were not adequate surrogate markers. MCV/WBC ratio correlated with clinical response, but was less useful than TGN for guiding clinical decisions. CONCLUSIONS Monitoring TGNs enables thiopurine therapy to be optimised and individualised, guiding effective treatment decisions and improving clinical outcomes.
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Affiliation(s)
- M Smith
- Department of Gastroenterology, St Thomas' Hospital, London, UK
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27
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Roberts RL, Barclay ML. Current relevance of pharmacogenetics in immunomodulation treatment for Crohn's disease. J Gastroenterol Hepatol 2012; 27:1546-54. [PMID: 22741564 DOI: 10.1111/j.1440-1746.2012.07220.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
No drug therapy is completely risk free, and the costs associated with non-response and adverse effects can exceed the cost of the therapy. The ultimate goal of pharmacogenetic research is to find robust genetic predictors of drug response that enable the development of prospective genetic tests to reliably identify patients at risk of non-response or of developing an adverse effect prior to the drug being prescribed. Currently, thiopurine S-methyltransferase (TPMT) deficiency is the only pharmacogenetic factor that is prospectively assessed before azathioprine or 6-mercaptopurine immunomodulation is commenced in patients with Crohn's disease (CD). As yet no other inherited determinant of drug response has made the transition from bench to bedside for the management of this disease. In this review we summarize what is known about TPMT deficiency and explore whether there is evidence to support a role of other genetic polymorphisms in predicting the response of CD patients to thiopurine drugs, methotrexate, and anti-tumor necrosis factor α (TNFα) therapy.
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Affiliation(s)
- Rebecca L Roberts
- Department of Surgical Sciences, Dunedin School of Medicine, Dunedin, New Zealand.
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28
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Citterio-Quentin A, Salvi JP, Boulieu R. Determination of inosine triphosphate pyrophosphatase phenotype in human red blood cells using HPLC. Ther Drug Monit 2012; 34:477-80. [PMID: 22673202 DOI: 10.1097/ftd.0b013e31825c2703] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Thiopurine drugs, widely used in cancer chemotherapy, inflammatory bowel disease, and autoimmune hepatitis, are responsible for common adverse events. Only some of these may be explained by genetic polymorphism of thiopurine S-methyltransferase. Recent articles have reported that inosine triphosphate pyrophosphatase (ITPase) deficiency was associated with adverse drug reactions toward thiopurine drug therapy. Here, we report a weak anion exchange high-performance liquid chromatography method to determine ITPase activity in red blood cells and to investigate the relationship with the occurrence of adverse events during azathioprine therapy. METHODS ITPase activity was assessed by the enzymatic conversion of inosine triphosphate (ITP) to inosine monophosphate (IMP). The reaction was stopped by heating for 3 minutes at 120°C. IMP, inosine diphosphate, and ITP were analyzed on a Hypersil APS-2 column, a weak anion exchange phase that exhibits both ionic and hydrophobic properties. RESULTS The chromatographic method reported allows the analysis of IMP, inosine diphosphate, and ITP in a single run in <12.5 minutes. The method was linear in the range 5-1500 μmole/L of IMP. Intraassay and interassay precisions were <5% for red blood cell lysates supplemented with 50, 500, and 1000 μmole/L IMP. Km and Vmax evaluated by Lineweaver-Burk plot were 677.4 μmole/L and 19.6 μmole·L·min, respectively. The frequency distribution of ITPase from 73 patients was investigated. CONCLUSIONS The method described is useful to determine the ITPase phenotype from patients on thiopurine therapy and to investigate the potential relation between ITPase deficiency and the occurrence of adverse events.
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Affiliation(s)
- Antony Citterio-Quentin
- Institut des Sciences Parmaceutiques et Biologiques, Pharmacie Clinique, Pharmacocinétique et Évaluation du Médicament, Université de Lyon, Université Lyon 1, Lyon, France
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Hindorf U, Appell ML. Genotyping should be considered the primary choice for pre-treatment evaluation of thiopurine methyltransferase function. J Crohns Colitis 2012; 6:655-9. [PMID: 22398041 DOI: 10.1016/j.crohns.2011.11.014] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2011] [Revised: 11/16/2011] [Accepted: 11/20/2011] [Indexed: 02/08/2023]
Abstract
BACKGROUND AND AIMS A pre-treatment determination of the thiopurine S-methyltransferase (TPMT) genotype or phenotype can identify patients at risk of developing severe adverse reactions from thiopurine treatment. The risk of misclassifying a patient might be dependent on the method used. The aim of this study was to investigate the concordance between TPMT genotyping and phenotyping. METHODS The data consist of 7195 unselected and consecutive TPMT genotype and phenotype determinations sent to the division of Clinical Pharmacology, Linköping, Sweden. TPMT activity was measured in red blood cells (RBC) and the genotype determined by pyrosequencing for the three most common TPMT variants (TPMT *2, *3A, *3C). RESULTS TPMT genotyping identified 89% as TPMT wild type (*1/*1), 10% as TPMT heterozygous and 0.5% as TMPT defective. The overall concordance between genotyping and phenotyping was 95%, while it was 96% among IBD patients (n=4024). Genotyping would have misclassified 8% of the TPMT defectives as heterozygous as compared to 11% if only TPMT activity had been measured. 11% of the heterozygous patients had a normal TPMT activity (>8.9 U/ml RBC) and 3% of the TPMT wild-type patients had an intermediate TPMT activity (2.5-8.9 U/ml RBC). CONCLUSIONS There is a risk for TPMT misclassification when only genotyping or phenotyping is used, but it is not reasonable to check both in all patients. Since TPMT genotyping is the more reliable test, especially in TPMT heterozygotes, we suggest that genotyping should be considered the primary choice for the pre-treatment evaluation of TPMT function before initiation of thiopurine therapy.
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Affiliation(s)
- Ulf Hindorf
- Department of Gastroenterology, Skåne University Hospital, Lund, Sweden.
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Adler J, Punglia DR, Dillman JR, Polydorides AD, Dave M, Al-Hawary MM, Platt JF, McKenna BJ, Zimmermann EM. Computed tomography enterography findings correlate with tissue inflammation, not fibrosis in resected small bowel Crohn's disease. Inflamm Bowel Dis 2012; 18:849-56. [PMID: 21710535 DOI: 10.1002/ibd.21801] [Citation(s) in RCA: 152] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Accepted: 05/20/2011] [Indexed: 12/13/2022]
Abstract
BACKGROUND It has become commonplace to categorize small intestinal Crohn's disease (CD) as "active" vs. "inactive" or "inflammatory" vs. "fibrotic" based on computed tomography enterography (CTE) findings. Data on histologic correlates of CTE findings are lacking. We aimed to compare CTE findings with histology from surgically resected specimens. We tested the hypothesis that CTE findings can distinguish tissue inflammation from fibrosis. METHODS Patients who underwent CTE within 3 months before intestinal resection for CD were retrospectively studied. Radiologists blinded to history and histology scored findings on CTE. Pathologists blinded to history and imaging scored resected histology. We compared histology with CTE findings and radiologists assessment of whether the stricture was likely "active" or "inactive." RESULTS In all, 22 patients met inclusion criteria. Inflammatory CTE findings correlated with histologic inflammation (rho = 0.52). Strictures believed to be "active" on CTE were more inflamed at histology (P = 0.0002). Strictures lacking inflammatory findings on CTE or considered "inactive" were not associated with greater histologic fibrosis or significant histologic inflammation. Upstream dilation was associated with greater tissue fibrosis in univariate (P = 0.014) but not in multivariate analysis (P = 0.53). Overall, histologic fibrosis correlated best with histologic inflammation (rho = 0.52). Strictures on CTE with the most active disease activity also had the most fibrosis on histology. CONCLUSIONS CTE findings of mesenteric hypervascularity, mucosal hyperenhancement, and mesenteric fat stranding predict tissue inflammation. However, small bowel stricture without CTE findings of inflammation does not predict the presence of tissue fibrosis. Therefore, caution should be used when using CTE criteria to predict the presence of scar tissue.
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Affiliation(s)
- Jeremy Adler
- Division of Pediatric Gastroenterology, Department of Pediatrics and Communicable Diseases, University of Michigan Health System, Ann Arbor, Michigan 48109, USA.
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Hofmann U, Heinkele G, Angelberger S, Schaeffeler E, Lichtenberger C, Jaeger S, Reinisch W, Schwab M. Simultaneous quantification of eleven thiopurine nucleotides by liquid chromatography-tandem mass spectrometry. Anal Chem 2012; 84:1294-301. [PMID: 22220820 DOI: 10.1021/ac2031699] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The prodrugs azathioprine and 6-mercaptopurine, which are well-established anticancer and immunosuppressive agents, are extensively metabolized by activating and inactivating enzymes. Whereas the 6-thioguanine nucleotides (TGN) are currently being considered as major active metabolites, methylthioinosine nucleotides seem to contribute to the cytotoxic effect as well. Thiopurine-related adverse drug reactions and thiopurine failure are frequent. Thus, therapeutic monitoring of TGN and methylthioinosine derivatives has been suggested to improve thiopurine therapy, however with limited success. To elucidate systematically underlying molecular mechanisms as potential explanation for interindividual variability of thiopurine response, we developed a novel highly specific and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for simultaneous quantitation of eleven mono-, di-, and triphosphates of thioguanosine, methylthioinosine, methylthioguanosine, and thioinosine. Using stable isotope-labeled analogues as internal standards obtained by chemical synthesis, an intra- and interassay variability below 8% and an accuracy of 92% to 107% were achieved in spiked quality control samples with known standards. All eleven metabolites could be determined in red blood cells from patients with inflammatory bowel diseases and long-term azathioprine therapy. Thus, our novel method opens a new avenue for the understanding of the thiopurine metabolism by quantitation of all important thiopurine nucleotide metabolites in one run.
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Affiliation(s)
- Ute Hofmann
- Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart, Germany
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Bierau J, Bakker JA, Schippers JA, Grashorn JAC, Lindhout M, Lowe SH, Paulussen ADC, Verbon A. Erythrocyte inosine triphosphatase activity is decreased in HIV-seropositive individuals. PLoS One 2012; 7:e30175. [PMID: 22272297 PMCID: PMC3260219 DOI: 10.1371/journal.pone.0030175] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Accepted: 12/13/2011] [Indexed: 01/28/2023] Open
Abstract
Background Inosine triphosphatase (ITPase) is encoded by the polymorphic gene ITPA and maintains low intracellular levels of the inosine nucleotides ITP and dITP. The most frequently reported polymorphisms are ITPA c.94C>A (rs 1127354) and ITPA c. 124+21 A>C (rs7270101). Some nucleoside-analogues used in the treatment of HIV-seropositive (HIV+) patients are potential substrates for ITPase. Therefore, the frequency of ITPA SNPs and ITPase activity were studied in a population of HIV+-patients. Methods The study population consisted of 222 patients, predominantly Caucasian males, >95% using HAART. Erythrocyte ITPase activity was determined by measuring the formation of IMP from ITP. ITPA genotype was determined by sequencing genomic DNA. Distribution of ITPase activity, genotype-phenotype correlation and allele frequencies were compared to 198 control subjects. The effect of nucleoside analogues on ITPase activity was studied using lymphoblastic T-cell cultures and human recombinant ITPase. Enzyme kinetic experiments were performed on erythrocyte ITPase from HIV+ patients and controls. Results No difference was observed in the allele frequencies between the HIV+-cohort (± HAART) and the control population. HIV+ carriers of the wild type and ITPA c.94C>A had significantly lower ITPase activities than control subjects with the same genotype (p<0.005). This was not observed in ITPA c. 124+21 A>C carriers. Nucleoside analogues did not affect ITPase activity in cell culture and human recombinant ITPase. Conclusion: ITPA population genetics were identical in HIV+ and control populations. However, the majority of HIV+-patients had decreased erythrocyte ITPase activity compared to controls, probably due to decreased amounts of ITPase protein. It seems unlikely that ITPase activity is decreased due to nucleoside analogues (HAART). Long-term effects of HIV-infection altering ITPase protein expression or stability may explain the phenomenon observed.
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Affiliation(s)
- Jörgen Bierau
- Department of Clinical Genetics, Maastricht University Medical Centre, Maastricht, The Netherlands.
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Chouchana L, Narjoz C, Beaune P, Loriot MA, Roblin X. Review article: the benefits of pharmacogenetics for improving thiopurine therapy in inflammatory bowel disease. Aliment Pharmacol Ther 2012; 35:15-36. [PMID: 22050052 DOI: 10.1111/j.1365-2036.2011.04905.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND Thiopurines represent an effective and widely prescribed therapy in inflammatory bowel disease (IBD). Concerns about toxicity, mainly resulting from a wide inter-individual variability in thiopurine metabolism, restrict their use. Optimal thiopurine dosing is challenging for preventing adverse drug reactions and improving clinical response. AIM To review efficacy and toxicity of thiopurines in IBD. To provide pharmacogenetic-based therapeutic recommendations. METHODS We conducted a query on PubMed database using 'inflammatory bowel disease', 'thiopurine', 'azathioprine', '6-mercaptopurine', 'TPMT', 'pharmacogenetics', 'TDM', and selected relevant articles, especially clinical studies. RESULTS Thiopurine metabolism - key enzyme: thiopurine S-methyltransferase (TPMT) - modulates clinical response, as it results in production of the pharmacologically active and toxic metabolites, the thioguanine nucleotides (6-TGN). Adjusting dosage according to TPMT status and/or metabolite blood levels is recommended for optimising thiopurine therapy (e.g. improving response rate up to 30% or decreasing haematological adverse events of 25%). Other enzymes or transporters of interest, as inosine triphosphatase (ITPase), glutathione S-transferase (GST), xanthine oxidase (XO), aldehyde oxidase (AOX), methylene tetrahydrofolate reductase (MTHFR) and ATP-binding cassette sub-family C member 4 (ABCC4) are reviewed and discussed for clinical relevance. CONCLUSIONS Based on the literature data, we provide a therapeutic algorithm for thiopurines therapy with starting dose recommendations depending on TPMT status and thereafter dose adjustments according to five metabolite profiles identified with therapeutic drug monitoring (TDM). This algorithm allows a dosage individualisation to optimise the management of patients under thiopurine. Furthermore, identification of new pharmacogenetic biomarkers is promising for ensuring maximal therapeutic response to thiopurines with a minimisation of the risk for adverse events.
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Affiliation(s)
- L Chouchana
- Assistance publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Biochimie, Pharmacogénétique et Oncologie Moléculaire, Paris, France
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Evidence for a functional genetic polymorphism of the Rho-GTPase Rac1. Implication in azathioprine response? Pharmacogenet Genomics 2011; 21:313-24. [PMID: 21372752 DOI: 10.1097/fpc.0b013e3283449200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Adverse effects of thiopurine drugs occur in 15-28% of patients and the majority is not explained by thiopurine-S-methyltransferase deficiency. Furthermore, approximately 9% of patients with inflammatory bowel disease are resistant to azathioprine therapy. Recently, the small guanosine triphosphatase, Rac1, was identified as an important molecular target of 6-thioguanine triphosphate, one of the active metabolite of thiopurines such as azathioprine. To date, no functional genetic polymorphism of the human Rac1 gene had been reported. OBJECTIVES Evidence for functional genetic polymorphisms of the human Rac1 gene and to investigate their relative contribution to the development of toxicity induced by azathioprine treatment in patients with inflammatory bowel disease. METHODS We first screened for polymorphisms in the Rac1 gene in genomic DNA samples from 92 unrelated Caucasian individuals. The functional consequences of identified polymorphisms were assessed in vitro using transient transfection assays in Jurkat and A549 cell lines. The relationship between polymorphisms of Rac1 and thiopurine response or hematotoxicity was studied in 128 patients under thiopurine treatment. RESULTS Three single nucleotide polymorphism and one variable number tandem repeat were identified in the promoter region of Rac1 gene. Interestingly, in Jurkat T cells, the c.-289G>C substitution and c.-283_-297[3] variable number tandem repeat displayed a significantly increased promoter activity (P<0.01) of 150 and 300%, respectively, compared with that of the wild-type sequence. Patients with thiopurine-S-methyltransferase mutations presented a significantly increased probability of developing hematotoxicity (odds ratio=5.68, 95% confidence interval=1.45-22.23, P=0.00625). Moreover, among the 75 patients who did not develop hematotoxicity, there was a marginally overrepresentation of functional genetic polymorphisms of Rac1 (odds ratio=0.18, 95% confidence interval=0.02-1.49, P=0.079). CONCLUSION This study constitutes the first report of a functional genetic polymorphism that could affect Rac1 expression and thus modulate the risk of adverse drug reaction in patients under thiopurine treatment. A larger scale (case-control) study should enable us to confirm or cancel these preliminary results.
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Association Between Adverse Effects Under Azathioprine Therapy and Inosine Triphosphate Pyrophosphatase Activity in Patients With Chronic Inflammatory Bowel Disease. Ther Drug Monit 2011; 33:321-8. [DOI: 10.1097/ftd.0b013e31821a7c34] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Ochi H, Maekawa T, Abe H, Hayashida Y, Nakano R, Kubo M, Tsunoda T, Hayes CN, Kumada H, Nakamura Y, Chayama K. ITPA polymorphism affects ribavirin-induced anemia and outcomes of therapy--a genome-wide study of Japanese HCV virus patients. Gastroenterology 2010; 139:1190-7. [PMID: 20637204 DOI: 10.1053/j.gastro.2010.06.071] [Citation(s) in RCA: 148] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2010] [Revised: 06/16/2010] [Accepted: 06/30/2010] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS Ribavirin-induced anemia is one of the major causes of discontinuation and dose reduction during anti-hepatitis C virus therapy. Factors influencing this anemia, especially host genetic factors, are poorly understood. In this study we investigated predictive factors in hepatitis C virus patients treated with combination therapy. METHODS We performed a 2-step genome-wide screening followed by replication analysis and fine-mapping using a total of 923 Japanese hepatitis C virus 1b-infected patients treated with pegylated-interferon plus ribavirin. We also applied logistic regression analysis to search for possible independent associations of clinical parameters and genetic variants with treatment-induced hemoglobin (Hb) decline as well as treatment outcomes. RESULTS We identified a variant, located upstream of the inosine triphosphate pyrophosphatase gene on chromosome 20p13 that is significantly associated with treatment-induced anemia (combined P = 6.0 × 10(-14)). Resequencing and fine-mapping revealed several single nucleotide polymorphisms (SNPs) strongly associated with Hb decline, including the nonsynonymous SNP rs1127354 (P = 3.5 × 10(-44)), which was recently reported for other ethnic groups. Another reported SNP, the splicing variant-related SNP rs7270101, was not polymorphic in the Japanese population. Stratified analysis based on rs1127354 genotype revealed that inosine triphosphate pyrophosphatase expression is not correlated with Hb decline, suggesting that rs1127354 is a direct causal variant in the Japanese population. Multivariate analysis demonstrated that age, baseline Hb, baseline platelet count, and rs1127354 were independently associated with severe anemia (Hb <10 g/dL). CONCLUSIONS A missense substitution in inosine triphosphate pyrophosphatase gene affects ribavirin-induced anemia in hepatitis C virus-infected Japanese patients.
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Affiliation(s)
- Hidenori Ochi
- Laboratory for Liver Diseases, RIKEN Center for Genomic Medicine, Hiroshima, Japan
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Waisertreiger ISR, Menezes MR, Randazzo J, Pavlov YI. Elevated Levels of DNA Strand Breaks Induced by a Base Analog in the Human Cell Line with the P32T ITPA Variant. J Nucleic Acids 2010; 2010. [PMID: 20936128 PMCID: PMC2948936 DOI: 10.4061/2010/872180] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Accepted: 07/11/2010] [Indexed: 12/29/2022] Open
Abstract
Base analogs are powerful antimetabolites and dangerous mutagens generated endogenously by oxidative stress, inflammation, and aberrant nucleotide biosynthesis. Human inosine triphosphate pyrophosphatase (ITPA) hydrolyzes triphosphates of noncanonical purine bases (i.e., ITP, dITP, XTP, dXTP, or their mimic: 6-hydroxyaminopurine (HAP) deoxynucleoside triphosphate) and thus regulates nucleotide pools and protects cells from DNA damage. We demonstrate that the model purine base analog HAP induces DNA breaks in human cells and leads to elevation of levels of ITPA. A human polymorphic allele of the ITPA, 94C->A encodes for the enzyme with a P32T amino-acid change and leads to accumulation of nonhydrolyzed ITP. The polymorphism has been associated with adverse reaction to purine base-analog drugs. The level of both spontaneous and HAP-induced DNA breaks is elevated in the cell line with the ITPA P32T variant. The results suggested that human ITPA plays a pivotal role in the protection of DNA from noncanonical purine base analogs.
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Affiliation(s)
- Irina S-R Waisertreiger
- Eppley Institute for Research in Cancer, University of Nebraska Medical Center, Omaha, NE 68198-6805, USA
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Ford LT, Berg JD. Thiopurine S-methyltransferase (TPMT) assessment prior to starting thiopurine drug treatment; a pharmacogenomic test whose time has come. J Clin Pathol 2010; 63:288-95. [PMID: 20354201 DOI: 10.1136/jcp.2009.069252] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Thiopurine S-methyltransferase (TPMT) is involved in the metabolism of thiopurine drugs. Patients that due to genetic variation lack this enzyme or have lower levels than normal, can be adversely affected if normal doses of thiopurines are prescribed. The evidence for measuring TPMT prior to starting patients on thiopurine drug therapy has been reviewed and the various approaches to establishing a service considered. Until recently clinical guidelines on the use of the TPMT varied by medical specialty. This has now changed, with clear guidance encouraging clinicians to use the TPMT test prior to starting any patient on thiopurine therapy. The TPMT test is the first pharmacogenomic test that has crossed from research to routine use. Several analytical approaches can be taken to assess TPMT status. The use of phenotyping supported with genotyping on selected samples has emerged as the analytical model that has enabled national referral services to be developed to a high level in the UK. The National Health Service now has access to cost-effective and timely TPMT assay services, with two laboratories undertaking the majority of the work at national level and with several local services developing. There appears to be adequate capacity and an appropriate internal market to ensure that TPMT assay services are commensurate with the clinical demand.
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Affiliation(s)
- L T Ford
- Clinical Biochemistry Department, SWBH NHS Trust, City Hospital, Dudley Road, Birmingham B18 5HQ, UK
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Hanai H, Iida T, Takeuchi K, Arai O, Watanabe F, Abe J, Maruyama Y, Oohata A, Ikeya K, Kageoka M, Miwa I, Yoshirou S, Hosoda Y, Kubota T. Thiopurine maintenance therapy for ulcerative colitis: the clinical significance of monitoring 6-thioguanine nucleotide. Inflamm Bowel Dis 2010; 16:1376-81. [PMID: 20049951 DOI: 10.1002/ibd.21190] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
BACKGROUND 6-Mercaptopurine (6-MP) is an effective maintenance medication in patients with ulcerative colitis (UC), but toxic effects like myelosuppression limit its clinical benefit. In the blood, 6-thioguanine (6-TGN) is formed from 6-MP and mediates the therapeutic efficacy and most of the toxicities of 6-MP. The level of 6-TGN depends on the activity of thiopurine methyltransferase (TPMT), inherited as 1 of its 3 polymorphic forms with low, moderate, or normal/high activity. Accordingly, the 6-MP dose needs to be pharmacogenetically guided. METHODS Patients with quiescent UC received 6-MP as maintenance therapy and 6-TGN was assayed as its concentrations in red blood cells (RBCs) done by high-performance liquid chromatography. In a preliminary investigation, 30 mg/day 6-MP (n = 50) was given orally over 12 weeks to determine the time course of blood 6-TGN level. Then 257 patients were given 6-MP at 15-80 mg/day in a stepwise manner based on RBC 6-TGN, white blood cell count, and body weight to monitor 6-MP efficacy and safety profiles. RESULTS At 30 mg/day 6-MP, RBC 6-TGN peaked over 4-8 weeks. In the main dosing study, the mean RBC 6-TGN level in patients who remained in remission during the 1-year observation time (n = 151) was 322.3 +/- 119.5 pmole/8 x 10(8) RBC versus 204.8 +/- 78.7 pmole/8 x 10(8) RBC in patients (n = 19) who relapsed (P < 0.001). Bone marrow suppression was seen almost exclusively at high 6-TGN concentration ranges. Further, a regression plot showed an inverse relationship between 6-TGN levels in RBC and TPMT enzyme activity. CONCLUSIONS By regularly measuring RBC 6-TGN in patients with quiescent UC receiving 6-MP as maintenance therapy, we could monitor bone marrow suppression as well as other toxic side effects. Potentially, this strategy should enable physicians to avoid thiopurine-related adverse effects and identify individuals who may benefit most from 6-MP maintenance therapy.
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Affiliation(s)
- Hiroyuki Hanai
- Centre for Gastroenterology and Inflammatory Bowel Disease Research, Hamamatsu South Hospital, Hamamatsu, Japan.
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Yamamoto K, Okada Y, Nakamura K, Hiromura K, Nojima Y, Nakamura T. Inosine triphosphate pyrophosphatase 94C> A polymorphism: clinical implications for patients with systemic lupus erythematosus treated with azathioprine. Expert Opin Drug Saf 2010; 9:447-57. [DOI: 10.1517/14740330903544474] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Koujirou Yamamoto
- Gunma University Graduate School of Medicine, Department of Clinical Pharmacology, 3-39-22 Showa-machi, Maebashi, Gunma 371-0034, Japan ;
| | - Yuko Okada
- Gunma University Graduate School of Medicine, Department of Clinical Pharmacology, 3-39-22 Showa-machi, Maebashi, Gunma 371-0034, Japan ;
| | - Katsunori Nakamura
- Gunma University Graduate School of Medicine, Department of Clinical Pharmacology, 3-39-22 Showa-machi, Maebashi, Gunma 371-0034, Japan ;
| | - Keiju Hiromura
- Gunma University Graduate School of Medicine, Department of Medicine and Clinical Science, Gunma, Japan
| | - Yoshihisa Nojima
- Gunma University Graduate School of Medicine, Department of Medicine and Clinical Science, Gunma, Japan
| | - Tomonori Nakamura
- Gunma University Graduate School of Medicine, Department of Clinical Pharmacology, 3-39-22 Showa-machi, Maebashi, Gunma 371-0034, Japan ;
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Smith MA, Marinaki AM, Sanderson JD. Pharmacogenomics in the treatment of inflammatory bowel disease. Pharmacogenomics 2010; 11:421-37. [PMID: 20235796 DOI: 10.2217/pgs.10.4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In recent years, the benefits of early aggressive treatment paradigms for inflammatory bowel disease have emerged. Symptomatic improvement is no longer considered adequate; instead, the aim of treatment has become mucosal healing and altered natural history. Nonetheless, we still fail to achieve these end points in a large number of our patients. There are many reasons why patients fail to respond or develop toxicity when exposed to drugs used for inflammatory bowel disease, but genetic variation is likely to account for a significant proportion of this. Some examples, notably thiopurine methyltransferase polymorphism in thiopurine treatment, are already established in clinical practice. We present a review of the expanding literature in this field, highlighting many interesting developments in pharmacogenomics applied to inflammatory bowel disease and, where possible, providing guidance on the translation of these developments into clinical practice.
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Affiliation(s)
- Melissa A Smith
- Department of Gastroenterology, 1st Floor, College House, St Thomas' Hospital, Lambeth Palace Road, London, SE1 7EH, UK
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Stocco G, Crews KR, Evans WE. Genetic polymorphism of inosine-triphosphate-pyrophosphatase influences mercaptopurine metabolism and toxicity during treatment of acute lymphoblastic leukemia individualized for thiopurine-S-methyl-transferase status. Expert Opin Drug Saf 2010; 9:23-37. [PMID: 20021291 DOI: 10.1517/14740330903426151] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
IMPORTANCE OF THE FIELD Although genetic polymorphisms in the gene encoding human thiopurine methyltransferase (TPMT) are known to have a marked effect on mercaptopurine metabolism and toxicity, there are many patients with wild-type TPMT who develop toxicity. Furthermore, when mercaptopurine dosages are adjusted in patients who are heterozygous at the TPMT locus, there are still some patients who develop toxicity for reasons that are not fully understood. Therefore, we recently studied the effects of a common polymorphism in another gene encoding an enzyme involved in mercaptopurine metabolism (SNP rs1127354 in inosine-triphospate-pyrophosphatase, ITPA), showing that genetic polymorphism of ITPA is a significant determinant of mercaptopurine metabolism and of febrile neutropenia following combination chemotherapy of acute lymphoblastic leukemia (ALL) in which mercaptopurine doses are individualized based on TPMT genotype. AREA COVERED IN THIS REVIEW In this review, we summarize the knowledge available about the effect and clinical relevance of TPMT and ITPA on mercaptopurine pharmacogenomics, with a particular focus on the use of this medication in pediatric patients with ALL. WHAT THE READER WILL GAIN Reader will gain insights into: i) the effects of pharmacogenomic traits on mercaptopurine toxicity and efficacy for the treatment of ALL and ii) individualization strategies that can be used to mitigate toxicity without compromising efficacy in pediatric patients with ALL. TAKE HOME MESSAGE Mercaptopurine dose can be adjusted on the basis of TPMT genotype to mitigate toxicity in pediatric patients with ALL. As treatment is individualized in this way for the most relevant genetic determinant of drug response (i.e., for mercaptopurine, TPMT), the importance of other genetic polymorphisms emerges (e.g., ITPA).
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Affiliation(s)
- Gabriele Stocco
- St. Jude Children's Research Hospital, Department of Pharmaceutical Sciences, 262 Danny Thomas Place MS 272, Memphis, TN 38105, USA
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Smith MA, Marinaki AM, Arenas M, Shobowale-Bakre M, Lewis CM, Ansari A, Duley J, Sanderson JD. Novel pharmacogenetic markers for treatment outcome in azathioprine-treated inflammatory bowel disease. Aliment Pharmacol Ther 2009; 30:375-84. [PMID: 19500084 DOI: 10.1111/j.1365-2036.2009.04057.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND Azathioprine (AZA) pharmacogenetics are complex and much studied. Genetic polymorphism in TPMT is known to influence treatment outcome. Xanthine oxidase/dehydrogenase (XDH) and aldehyde oxidase (AO) compete with TPMT to inactivate AZA. AIM To assess whether genetic polymorphism in AOX1, XDH and MOCOS (the product of which activates the essential cofactor for AO and XDH) is associated with AZA treatment outcome in IBD. METHODS Real-time PCR was conducted for a panel of single nucleotide polymorphism (SNPs) in AOX1, XDH and MOCOS using TaqMan SNP genotyping assays in a prospective cohort of 192 patients receiving AZA for IBD. RESULTS Single nucleotide polymorphism AOX1 c.3404A > G (Asn1135Ser, rs55754655) predicted lack of AZA response (P = 0.035, OR 2.54, 95%CI 1.06-6.13) and when combined with TPMT activity, this information allowed stratification of a patient's chance of AZA response, ranging from 86% in patients where both markers were favourable to 33% where they were unfavourable (P < 0.0001). We also demonstrated a weak protective effect against adverse drug reactions (ADRs) from SNPs XDH c.837C > T (P = 0.048, OR 0.23, 95% CI 0.05-1.05) and MOCOS c.2107A > C, (P = 0.058 in recessive model, OR 0.64, 95%CI 0.36-1.15), which was stronger where they coincided (P = 0.019). CONCLUSION These findings have important implications for clinical practice and our understanding of AZA metabolism.
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Affiliation(s)
- M A Smith
- Department of Gastroenterology, Guy's & St. Thomas' NHS Foundation Trust, London, UK
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Functional study of the P32T ITPA variant associated with drug sensitivity in humans. J Mol Biol 2009; 392:602-13. [PMID: 19631656 DOI: 10.1016/j.jmb.2009.07.051] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Revised: 07/15/2009] [Accepted: 07/16/2009] [Indexed: 12/12/2022]
Abstract
Sanitization of the cellular nucleotide pools from mutagenic base analogues is necessary for the accuracy of transcription and replication of genetic material and plays a substantial role in cancer prevention. The undesirable mutagenic, recombinogenic, and toxic incorporation of purine base analogues [i.e., ITP, dITP, XTP, dXTP, or 6-hydroxylaminopurine (HAP) deoxynucleoside triphosphate] into nucleic acids is prevented by inosine triphosphate pyrophosphatase (ITPA). The ITPA gene is a highly conserved, moderately expressed gene. Defects in ITPA orthologs in model organisms cause severe sensitivity to HAP and chromosome fragmentation. A human polymorphic allele, 94C-->A, encodes for the enzyme with a P32T amino acid change and leads to accumulation of non-hydrolyzed ITP. ITPase activity is not detected in erythrocytes of these patients. The P32T polymorphism has also been associated with adverse sensitivity to purine base analogue drugs. We have found that the ITPA-P32T mutant is a dimer in solution, as is wild-type ITPA, and has normal ITPA activity in vitro, but the melting point of ITPA-P32T is 5 degrees C lower than that of wild-type. ITPA-P32T is also fully functional in vivo in model organisms as determined by a HAP mutagenesis assay and its complementation of a bacterial ITPA defect. The amount of ITPA protein detected by Western blot is severely diminished in a human fibroblast cell line with the 94C-->A change. We propose that the P32T mutation exerts its effect in certain human tissues by cumulative effects of destabilization of transcripts, protein stability, and availability.
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Kurzawski M, Dziewanowski K, Lener A, Drozdzik M. TPMT but not ITPA gene polymorphism influences the risk of azathioprine intolerance in renal transplant recipients. Eur J Clin Pharmacol 2009; 65:533-40. [PMID: 19229528 DOI: 10.1007/s00228-009-0630-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Accepted: 01/28/2009] [Indexed: 01/29/2023]
Abstract
PURPOSE Thiopurine drugs have to be withdrawn in 10-30% of cases due to side effects, and it has been presented that genetic factors may be responsible for some of reported toxicity cases. Among polymorphic enzymes of thiopurines' metabolic pathway, thiopurine S-methyltransferase (TPMT) has been studied most extensively, and some recent studies point to inosine triphosphate pyrophosphohydrolase (ITPA) polymorphism as an additional toxicity risk factor. METHODS The aim of the current study was to evaluate an association between TPMT and ITPA gene polymorphisms and drug intolerance in a cohort of 157 renal transplant recipients treated with azathioprine (AZA). Each subject was genotyped for the presence of variant TPMT (*2, *3A, *3B, and *3C) and ITPA (94C>A and IVS2+21A>C) alleles. RESULTS Mean AZA dose, mean white-blood-cell count, and platelet count in the course of treatment were lower in carriers of variant TPMT alleles compared to patients with TPMT wild-type genotype. Leukocyte numbers fell below 4.0 x 10(9)/L in 41.2% of TPMT heterozygous renal transplant recipients, compared to only 18.0% of wild-type patients (P < 0.01). In contrast, ITPA genotype did not influence AZA dose, hematological parameters, or leucopenia risk. CONCLUSIONS Our results suggest that routine genotyping of renal transplant recipients for TPMT variants may be useful in reducing the risk of AZA-related myelotoxicity, but there is not enough evidence to introduce ITPA testing into clinical practice.
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Affiliation(s)
- Mateusz Kurzawski
- Department of Pharmacology, Pomeranian Medical University, Powstancow Wlkp. 72, Szczecin 70-111, Poland.
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Chan A, Stüve O, von Ahsen N. Immunosuppression in clinical practice: approaches to individualized therapy. J Neurol 2009; 255 Suppl 6:22-7. [PMID: 19300956 DOI: 10.1007/s00415-008-6005-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Despite novel immunoactive agents, immunosuppressants still play a considerable role in the treatment of MS, especially in rapidly progressive cases. Given the limited tolerability and potentially severe side effects of most immunosuppressive drugs, identification of patients with a favorable benefit-risk profile is essential. A narrow therapeutic index, with sometimes high interindividual variability in terms of response and side effects may partially be explained by genetic factors affecting different metabolic pathways. Here, we will review practical aspects in the clinical use of immunosuppressants in MS and discuss approaches to individualized treatment schemes, including novel pharmacogenetic strategies.
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Affiliation(s)
- Andrew Chan
- Department of Neurology, Ruhr University Bochum, St. Josef Hospital, Gudrunstr. 56, 44791 Bochum, Germany.
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Ansari A, Arenas M, Greenfield SM, Morris D, Lindsay J, Gilshenan K, Smith M, Lewis C, Marinaki A, Duley J, Sanderson J. Prospective evaluation of the pharmacogenetics of azathioprine in the treatment of inflammatory bowel disease. Aliment Pharmacol Ther 2008; 28:973-83. [PMID: 18616518 DOI: 10.1111/j.1365-2036.2008.03788.x] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
AIM To investigate whether pharmacogenetic loci or metabolite concentrations explain clinical response or side effects to AZA. METHODS Patients with IBD were given 2 mg/kg of AZA without dose escalation or adjustment. Serial clinical response, thiopurine methyl transferase (TPMT) activity and thioguanine nucleotide (TGN) concentrations were measured over 6 months. All patients were genotyped for inosine triphosphatase (ITPase) and TPMT. Clinical response and side effects were compared to these variables. RESULTS Two hundred and seven patients were analysed. Thirty-nine per cent withdrew due to adverse effects. Heterozygous TPMT genotype strongly predicted adverse effects (79% heterozygous vs. 35% wild-type TPMT, P < 0.001). The ITPA 94C>A mutation was associated with withdrawal due to flu-like symptoms (P = 0.014). A baseline TPMT activity below 35 pmol/h/mg/Hb was associated with a greater chance of clinical response compared with a TPMT above 35 pmo/h/mg/Hb (81% vs. 43% respectively, P < 0.001). Patients achieving a mean TGN level above 100 were significantly more likely to respond (P = 0.0017). CONCLUSIONS TPMT testing predicts adverse effects and reduced chance of clinical response (TPMT >35 pmol/h/mg/Hb). ITPase deficiency is a predictor of adverse effects and TGN concentrations above 100 correlate with clinical response.
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Affiliation(s)
- A Ansari
- Department of Gastroenterology, St Thomas' Hospitals Foundation, NHS Trust, London, UK
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Stocco G, Cheok MH, Crews KR, Dervieux T, French D, Pei D, Yang W, Cheng C, Pui CH, Relling MV, Evans WE. Genetic polymorphism of inosine triphosphate pyrophosphatase is a determinant of mercaptopurine metabolism and toxicity during treatment for acute lymphoblastic leukemia. Clin Pharmacol Ther 2008; 85:164-72. [PMID: 18685564 DOI: 10.1038/clpt.2008.154] [Citation(s) in RCA: 167] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The influence of genetic polymorphism in inosine triphosphate pyrophosphatase (ITPA) on thiopurine-induced adverse events has not been investigated in the context of combination chemotherapy for acute lymphoblastic leukemia (ALL). This study investigated the effects of a common ITPA variant allele (rs41320251) on mercaptopurine metabolism and toxicity during treatment of children with ALL. Significantly higher concentrations of methyl mercaptopurine nucleotides were found in patients with the nonfunctional ITPA allele. Moreover, there was a significantly higher probability of severe febrile neutropenia in patients with a variant ITPA allele among patients whose dose of mercaptopurine had been adjusted for TPMT genotype. In a cohort of patients whose mercaptopurine dose was not adjusted for TPMT phenotype, the TPMT genotype had a greater effect than the ITPA genotype. In conclusion, genetic polymorphism of ITPA is a significant determinant of mercaptopurine metabolism and of severe febrile neutropenia, after combination chemotherapy for ALL in which mercaptopurine doses are individualized on the basis of TPMT genotype.
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Affiliation(s)
- G Stocco
- Department of Pharmaceutical Sciences, St Jude Children's Research Hospital, Memphis, Tennessee, USA
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Abstract
The considerable interindividual differences in efficacy and side effects of commonly used medications in Crohn’s disease are partly owing to genetic polymorphisms. Many genetic variants have been studied in genes possibly involved in the metabolism or mechanism of action of therapeutic agents such as glucocorticosteroids, azathioprine/6-mercaptopurine, methotrexate, calcineurin inhibitors or anti-TNF agents. However, the only test translated into clinical practice is thiopurine S-methyltransferase (TPMT) genotyping for hematological toxicity of thiopurine treatment. To date, there are no other meaningful applications for pharmacogenomics in clinical practice of Crohn’s disease. In the future, designed therapeutic trials should possibly permit the development of predictive models including genotypic markers, such as that proposed for the clinical outcome after infliximab therapy, which includes an apoptotic pharmacogenetic index. The recent identification of new susceptibility genes provides additional candidate markers that have possible effects on the outcomes of therapies, and prioritizes new therapeutic targets, such as the IL-23 pathway. Futher innovative approaches might be relevant for the pharmacogenetic investigation of gene variants implied in innate immune pattern recognition and autophagy.
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Affiliation(s)
- Helga-Paula Török
- University of Munich, Department of Internal Medicine II, Campus Großhadern, Marchioninistr. 15, D-81377 Munich, Germany
| | - Burkhard Göke
- University of Munich, Department of Internal Medicine II, Campus Großhadern, Marchioninistr. 15, D-81377 Munich, Germany
| | - Astrid Konrad
- University of Munich, Department of Internal Medicine II, Campus Großhadern, Marchioninistr. 15, D-81377 Munich, Germany
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Gisbert JP, Gomollón F. Thiopurine-induced myelotoxicity in patients with inflammatory bowel disease: a review. Am J Gastroenterol 2008; 103:1783-800. [PMID: 18557712 DOI: 10.1111/j.1572-0241.2008.01848.x] [Citation(s) in RCA: 179] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
AIM Probably, the most important and potentially lethal adverse event of azathioprine (AZA) and mercaptopurine (MP) is myelosuppression. Our aim was to conduct a review of AZA/MP-induced myelotoxicity in inflammatory bowel disease (IBD) patients. METHODS Bibliographical searches were performed in MEDLINE/EMBASE. The studies evaluating thiopurine-induced myelotoxicity in patients with IBD were reviewed. The cumulative incidence and the incidence rate of AZA/MP-induced myelotoxicity were calculated by a meta-analysis. RESULTS In total, 66 studies (8,302 patients) were included. The cumulative incidence of AZA/MP-induced myelotoxicity was 7% (95% confidence interval [CI] 6-8%). The incidence rate (per patient and year of treatment) of the drug-induced myelotoxicity was 3% (95% CI 3-4%). The risk was roughly similar with AZA and with MP (7%vs 9%). The duration of AZA/MP treatment in patients with myelotoxicity ranged from 12 days to 27 yr. The cumulative incidence of infections among AZA/MP-induced myelotoxicity patients was 6.5%. The cumulative incidence of severe myelotoxicity was 1.1% (incidence rate 0.9%). Three deaths were reported due to myelotoxicity (cumulative incidence 0.06%, 95% CI 0.02-0.17%). The risk of death among patients who developed myelotoxicity was 0.94% (95% CI 0.32-2.70%). CONCLUSION The incidence rate of myelotoxicity in IBD patients receiving AZA/MP is approximately 3% per patient and year of treatment. Although bone marrow toxicity may develop at any time after starting the therapy, this happens more frequently during the first months. The incidence rate of severe myelotoxicity is less than 1% per patient and year of treatment, and the mortality risk is less than 0.1% (which means that the risk of death among IBD patients who develop myelotoxicity is approximately 1%).
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Affiliation(s)
- Javier P Gisbert
- Gastroenterology Unit, Hospital Universitario de la Princesa, Madrid, Spain
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