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Šmid A, Štajdohar M, Milek M, Urbančič D, Karas Kuželički N, Tamm R, Metspalu A, Mlinarič-Raščan I. Transcriptome analysis reveals involvement of thiopurine S-methyltransferase in oxidation-reduction processes. Eur J Pharm Sci 2024; 192:106616. [PMID: 37865284 DOI: 10.1016/j.ejps.2023.106616] [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] [Received: 07/18/2023] [Revised: 10/18/2023] [Accepted: 10/18/2023] [Indexed: 10/23/2023]
Abstract
Thiopurine S-methyltransferase (TPMT) is an important enzyme involved in the deactivation of thiopurines and represents a major determinant of thiopurine-related toxicities. Despite its well-known importance in thiopurine metabolism, the understanding of its endogenous role is lacking. In the present study, we aimed to gain insight into the molecular processes involving TPMT by applying a data fusion approach to analyze whole-genome expression data. The RNA profiling was done on whole blood samples from 1017 adult male and female donors to the Estonian biobank using Illumina HTv3 arrays. Our results suggest that TPMT is closely related to genes involved in oxidoreductive processes. The in vitro experiments on different cell models confirmed that TPMT influences redox capacity of the cell by altering S-adenosylmethionine (SAM) consumption and consequently glutathione (GSH) synthesis. Furthermore, by comparing gene networks of subgroups of individuals, we identified genes, which could have a role in regulating TPMT activity. The biological relevance of identified genes and pathways will have to be further evaluated in molecular studies.
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Affiliation(s)
- Alenka Šmid
- Department of Clinical Biochemistry, Faculty of Pharmacy, University of Ljubljana, Slovenia.
| | | | - Miha Milek
- Department of Clinical Biochemistry, Faculty of Pharmacy, University of Ljubljana, Slovenia; Core Unit Bioinformatics, Berlin Institute of Health at Charite, Germany
| | - Dunja Urbančič
- Department of Clinical Biochemistry, Faculty of Pharmacy, University of Ljubljana, Slovenia
| | - Nataša Karas Kuželički
- Department of Clinical Biochemistry, Faculty of Pharmacy, University of Ljubljana, Slovenia
| | - Riin Tamm
- Estonian Genome Center, Institute of Genomics and Institute of Molecular and Cell Biology, University of Tartu, Estonia; Youth and Talent Policy Department, Estonian Ministry of Education and Research, Estonia
| | - Andres Metspalu
- Estonian Genome Center, Institute of Genomics and Institute of Molecular and Cell Biology, University of Tartu, Estonia
| | - Irena Mlinarič-Raščan
- Department of Clinical Biochemistry, Faculty of Pharmacy, University of Ljubljana, Slovenia.
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Selvestrel D, Stocco G, Aloi M, Arrigo S, Cardile S, Cecchin E, Congia M, Curci D, Gatti S, Graziano F, Langefeld CD, Lucafò M, Martelossi S, Martinelli M, Pagarin S, Scarallo L, Stacul EF, Strisciuglio C, Thompson S, Zuin G, Decorti G, Bramuzzo M. DNA methylation of the TPMT gene and azathioprine pharmacokinetics in children with very early onset inflammatory bowel disease. Biomed Pharmacother 2023; 157:113901. [PMID: 36462311 DOI: 10.1016/j.biopha.2022.113901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 10/12/2022] [Accepted: 10/17/2022] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND Thiopurine methyltransferase (TPMT) is a crucial enzyme for azathioprine biotransformation and its activity is higher in very early onset inflammatory bowel disease (VEO-IBD) patients than in adolescents with IBD (aIBD). AIMS The aims of this pharmacoepigenetic study were to evaluate differences in peripheral blood DNA methylation of the TPMT gene and in azathioprine pharmacokinetics in patients with VEO-IBD compared to aIBD. METHODS The association of age with whole genome DNA methylation profile was evaluated in a pilot group of patients and confirmed by a meta-analysis on 3 cohorts of patients available on the public functional genomics data repository. Effects of candidate CpG sites in the TPMT gene were validated in a larger cohort using pyrosequencing. TPMT activity and azathioprine metabolites (TGN) were measured in patients' erythrocytes by HPLC and associated with patients' age group and TPMT DNA methylation. RESULTS Whole genome DNA methylation pilot analysis, combined with the meta-analysis revealed cg22736354, located on TPMT downstream neighboring region, as the only statistically significant CpG whose methylation increases with age, resulting lower in VEO-IBD patients compared to aIBD (median 9.6% vs 12%, p = 0.029). Pyrosequencing confirmed lower cg22736354 methylation in VEO-IBD patients (median 4.0% vs 6.0%, p = 4.6 ×10-5). No differences in TPMT promoter methylation were found. Reduced cg22736354 methylation was associated with lower TGN concentrations (rho = 0.31, p = 0.01) in patients with VEO-IBD and aIBD. CONCLUSION Methylation of cg22736354 in TPMT gene neighborhood is lower in patients with VEO-IBD and is associated with reduced azathioprine inactivation and increased TGN concentrations.
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Affiliation(s)
| | - Gabriele Stocco
- Institute for Maternal and Child Health, IRCCS "Burlo Garofolo", Trieste, Italy; Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | - Marina Aloi
- Women's and Children's Health Department, Pediatric Gastroenterology and Hepatology Unit, Sapienza University of Rome, Rome, Italy
| | - Serena Arrigo
- Pediatric Gastroenterology and Endoscopy Unit, Institute 'Giannina Gaslini', Genoa, Italy
| | - Sabrina Cardile
- Hepatology and Gastroenterology Unit, Bambino Gesù Hospital, Rome, Italy
| | - Erika Cecchin
- Experimental and Clinical Pharmacology, Centro di Riferimento Oncologico di Aviano (CRO) IRCCS, Aviano, Italy
| | - Mauro Congia
- Pediatric Clinic and Rare Diseases, Microcitemic Pediatric Hospital Antonio Cao, Azienda Ospedaliera Brotzu, Cagliari, Italy
| | - Debora Curci
- Institute for Maternal and Child Health, IRCCS "Burlo Garofolo", Trieste, Italy
| | - Simona Gatti
- Department of Pediatrics, Università Politecnica delle Marche, Ancona, Italy
| | | | - Carl D Langefeld
- Department of Biostatistics and Data Science, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Marianna Lucafò
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | | | - Massimo Martinelli
- Department of Translational Medical Science, Section of Pediatrics, University of Naples "Federico II", Naples, Italy
| | - Sofia Pagarin
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | - Luca Scarallo
- University of Florence-Meyer Hospital, Florence, Italy
| | | | - Caterina Strisciuglio
- Departement of Woman, Child and General and Specialistic Surgery, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Susan Thompson
- Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH, USA
| | - Giovanna Zuin
- Department of Pediatrics, University of Milano-Bicocca, Foundation MBBM/San Gerardo Hospital, Monza, Italy
| | - Giuliana Decorti
- Institute for Maternal and Child Health, IRCCS "Burlo Garofolo", Trieste, Italy; Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy.
| | - Matteo Bramuzzo
- Gastroenterology, Digestive Endoscopy and Nutrition Unit, Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
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Abstract
Almost 50% of prescription drugs lack age-appropriate dosing guidelines and therefore are used "off-label." Only ~10% drugs prescribed to neonates and infants have been studied for safety or efficacy. Immaturity of drug metabolism in children is often associated with drug toxicity. This chapter summarizes data on the ontogeny of major human metabolizing enzymes involved in oxidation, reduction, hydrolysis, and conjugation of drugs. The ontogeny data of individual drug-metabolizing enzymes are important for accurate prediction of drug pharmacokinetics and toxicity in children. This information is critical for designing clinical studies to appropriately test pharmacological hypotheses and develop safer pediatric drugs, and to replace the long-standing practice of body weight- or surface area-normalized drug dosing. The application of ontogeny data in physiologically based pharmacokinetic model and regulatory submission are discussed.
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Implementing Pharmacogenomics Testing: Single Center Experience at Arkansas Children's Hospital. J Pers Med 2021; 11:jpm11050394. [PMID: 34064668 PMCID: PMC8150685 DOI: 10.3390/jpm11050394] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/03/2021] [Accepted: 05/06/2021] [Indexed: 02/07/2023] Open
Abstract
Pharmacogenomics (PGx) is a growing field within precision medicine. Testing can help predict adverse events and sub-therapeutic response risks of certain medications. To date, the US FDA lists over 280 drugs which provide biomarker-based dosing guidance for adults and children. At Arkansas Children’s Hospital (ACH), a clinical PGx laboratory-based test was developed and implemented to provide guidance on 66 pediatric medications for genotype-guided dosing. This PGx test consists of 174 single nucleotide polymorphisms (SNPs) targeting 23 clinically actionable PGx genes or gene variants. Individual genotypes are processed to provide per-gene discrete results in star-allele and phenotype format. These results are then integrated into EPIC- EHR. Genomic indicators built into EPIC-EHR provide the source for clinical decision support (CDS) for clinicians, providing genotype-guided dosing.
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Kouwenberg TW, van den Bosch BJC, Bierau J, Te Loo DMWM, Coenen MJH, Hagleitner MM. Dosage of 6-Mercaptopurine in Relation to Genetic TPMT and ITPA Variants: Toward Individualized Pediatric Acute Lymphoblastic Leukemia Maintenance Treatment. J Pediatr Hematol Oncol 2020; 42:e94-e97. [PMID: 31895215 DOI: 10.1097/mph.0000000000001707] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
6-mercaptopurine (6-MP) is the mainstay in pediatric acute lymphoblastic leukemia (ALL) maintenance treatment. Variants in genes coding for thiopurine S-methyl transferase (TPMT) and inosine triphosphate pyrophosphatase (ITPA) are known to influence 6-MP metabolism. We determined TPMT and ITPA genotype and enzyme activity and the mean 6-MP doses during maintenance treatment in 40 children treated for ALL according to the Dutch Childhood Oncology Group (DCOG)-ALL11 protocol in the Radboudumc Amalia Children's Hospital, Nijmegen, The Netherlands. Patients with genetic variants in TPMT (N=3) had significantly lower TPMT enzyme activity (mean 0.46 vs. 0.72 µmol/mmol hemoglobin/h, P=0.005). Although the difference was not statistically significant, they were treated with lower mean 6-MP doses (28.1 mg/m [SD 25.5 mg/m] vs. 41.3 mg/m [SD 17.2 mg/m], P=0.375). In patients with genetic ITPA variants (N=21), ITPA enzyme activity was significantly lowered (mean 3.67 vs. 6.84 mmol/mmol hemoglobin/h, P<0.0005). The mean 6-MP doses did not differ between patients with and without variants in ITPA (40.0 mg/m [SD 20.3 mg/m] vs. 40.6 mg/m [SD 14.9 mg/m], P=0.663). The TPMT genotype, but not the ITPA genotype, should be considered as part of standard evaluation before starting ALL maintenance treatment.
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Affiliation(s)
- Theodorus W Kouwenberg
- Department of Pediatric Hematology and Oncology, Radboudumc Amalia Children's Hospital, Nijmegen
| | | | - Jörgen Bierau
- Department of Clinical Genetics, Maastricht University Medical Center, Maastricht
| | | | - Marieke J H Coenen
- Department of Human Genetics, Radboud Institute for Health Sciences, Radboudumc, Nijmegen
| | - Melanie M Hagleitner
- Department of Pediatric Hematology and Oncology, Radboudumc Amalia Children's Hospital, Nijmegen.,Princess Máxima Center for Pediatric Oncology, Utrecht, The Netherlands
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Lorenzoni PJ, Kay CSK, Zanlorenzi MF, Ducci RDP, Werneck LC, Scola RH. Myasthenia gravis and azathioprine treatment: Adverse events related to thiopurine S-methyl-transferase (TPMT) polymorphisms. J Neurol Sci 2020; 412:116734. [PMID: 32070863 DOI: 10.1016/j.jns.2020.116734] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 01/30/2020] [Accepted: 02/11/2020] [Indexed: 02/07/2023]
Abstract
Azathioprine (AZA) is the most common immunosuppressive drug used to treat myasthenia gravis (MG). To analyses the prevalence of thiopurine S-methyl-transferase (TPMT) genotypes and their association with adverse events due to azathioprine therapy in MG patients. Allele-specific polymerase chain reaction (PCR) and PCR with restriction fragment length polymorphism (RFLP) analysis were carried out to determine the prevalence of the most common TPMT genotypes (*2, *3A, *3B and *3C) in 50 MG patients from Southern Brazilian. The frequency of adverse reactions due to azathioprine therapy was analysed and correlated with different genotypes groups. The prevalence of TPMT gene variants was 12%. The allelic frequency of variant TPMT*2 (C238G), TPMT*3A (G460A/A719G), TPMT*3B (G460A), and TPMT*3C (A719G) genotypes was 1, 3, 2 and 1%, respectively. Adverse events occurred in 44%, of MG patients, of which 86% were minor and 14% were major. One patient, who presented a major adverse event (bone marrow suppression), was homozygous for the TPMT*3A genotype. Our study estimated the prevalence of TPMT genotypes for Brazilian MG patients. The profile of TPMT genotypes was different from other Brazilian populations. Hardy-Weinberg equilibrium and allelic frequencies of TPMT*3A and TPMT*3B, respectively, were different than expected, a finding that suggests a possible founder effect. Major adverse events were statistically significant for TPMT genotypes compared to wild-type. Although TPMT genotype has been associated with AZA-related adverse events, since no statistically significant difference among wild-type and other TPMT genotypes for minor adverse events, our study supports the view that TPMT genotype alone is not enough to adequately personalise the AZA therapy in MG patients. In conclusion, these results were important to characterise the prevalence of TPMT gene variants in MG patients treated with AZA and correlate the adverse events of this therapy in a real-world outpatient clinic from Southern Brazil.
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Affiliation(s)
- Paulo José Lorenzoni
- Service of Neuromuscular Disorders, Division of Neurology, Department of Internal Medicine, Hospital de Clínicas, Universidade Federal do Paraná (UFPR), Curitiba, Brazil.
| | - Cláudia Suemi Kamoi Kay
- Service of Neuromuscular Disorders, Division of Neurology, Department of Internal Medicine, Hospital de Clínicas, Universidade Federal do Paraná (UFPR), Curitiba, Brazil
| | - Marcelo Farago Zanlorenzi
- Service of Neuromuscular Disorders, Division of Neurology, Department of Internal Medicine, Hospital de Clínicas, Universidade Federal do Paraná (UFPR), Curitiba, Brazil
| | - Renata Dal-Prá Ducci
- Service of Neuromuscular Disorders, Division of Neurology, Department of Internal Medicine, Hospital de Clínicas, Universidade Federal do Paraná (UFPR), Curitiba, Brazil
| | - Lineu Cesar Werneck
- Service of Neuromuscular Disorders, Division of Neurology, Department of Internal Medicine, Hospital de Clínicas, Universidade Federal do Paraná (UFPR), Curitiba, Brazil
| | - Rosana Herminia Scola
- Service of Neuromuscular Disorders, Division of Neurology, Department of Internal Medicine, Hospital de Clínicas, Universidade Federal do Paraná (UFPR), Curitiba, Brazil
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PACSIN2 rs2413739 influence on thiopurine pharmacokinetics: validation studies in pediatric patients. THE PHARMACOGENOMICS JOURNAL 2019; 20:415-425. [PMID: 31792371 DOI: 10.1038/s41397-019-0130-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 11/09/2019] [Accepted: 11/20/2019] [Indexed: 12/11/2022]
Abstract
The aim of the study was to validate the impact of the single-nucleotide polymorphism rs2413739 (T > C) in the PACSIN2 gene on thiopurines pharmacological parameters and clinical response in an Italian cohort of pediatric patients with acute lymphoblastic leukemia (ALL) and inflammatory bowel disease (IBD). In ALL, PACSIN2 rs2413739 T allele was associated with a significant reduction of TPMT activity in erythrocytes (p = 0.0094, linear mixed-effect model, multivariate analysis considering TPMT genotype) and increased severe gastrointestinal toxicity during consolidation therapy (p = 0.049). A similar trend was present also for severe hematological toxicity during maintenance. In IBD, no significant effect of rs2413739 could be found on TPMT activity, however azathioprine effectiveness was reduced in patients carrying the T allele (linear mixed effect, p = 0.0058). In PBMC from healthy donors, a positive correlation between PACSIN2 and TPMT protein concentration could be detected (linear mixed effect, p = 0.045). These results support the role of PACSIN2 polymorphism on TPMT activity and mercaptopurine adverse effects in patients with ALL. Further evidence on PBMC and pediatric patients with IBD supports an association between PACSIN2 variants, TPMT activity, and thiopurines effects, even if more studies are needed since some of these effects may be tissue specific.
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Wu F, Melis R, McMillin GA, Johnson-Davis KL. Retrospective Data Analysis of the Influence of Age and Sex on TPMT Activity and Its Phenotype-Genotype Correlation. J Appl Lab Med 2019; 3:827-838. [PMID: 31639757 DOI: 10.1373/jalm.2018.027276] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 10/19/2018] [Indexed: 12/27/2022]
Abstract
BACKGROUND Therapeutic efficacy and toxicity of thiopurine drugs (used as anticancer and immunosuppressant agents) are affected by thiopurine S-methyltransferase (TPMT) enzyme activity. TPMT genotype and/or phenotype is used to predict the risk for adverse effects before drug administration. Inosine triphosphate pyrophosphatase (ITPA) is another enzyme involved in thiopurine metabolism. In this study, we aimed to evaluate (a) frequency of various TPMT phenotypes and genotypes, (b) correlations between them, (c) influence of age and sex on TPMT activity, and (d) distribution of ITPA variants among various TPMT subgroups. METHODS TPMT enzyme activity was determined by LC-MS/MS. TPMT (*2,*3A-C) and ITPA (rs1127354, rs7270101) genotypes were determined using a customized TaqMan® OpenArray®. RESULTS TPMT enzyme activity varied largely (6.3-90 U/mL). The frequency of low, intermediate, normal, and high activity was 0.5% (n = 230), 13.1% (n = 5998), 86.1% (n = 39448), and 0.28% (n = 126), respectively. No significant difference in TPMT activity in relation to age and sex was found. Genotype analysis revealed the frequency of variant TPMT alleles was 6.73% (*3A, n = 344), 0.05% (*3B, n = 2), 2.22% (*3C, n = 95), and 0.42% (*2, n = 19). Analysis of paired phenotype and genotype showed that TPMT activity in samples with variant allele(s) was significantly lower than those without variant alleles. Lastly, an equal distribution of ITPA variants was found among normal and abnormal TPMT activity. CONCLUSIONS This retrospective data analysis demonstrated a clustering of variant TPMT genotypes with phenotypes, no significant influence of age and sex on TPMT activity, and an equal distribution of ITPA variants among various TPMT subgroups.
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Affiliation(s)
- Fang Wu
- Department of Pathology and Laboratory Medicine, St. Paul's Hospital, Saskatchewan Health Authority, Saskatoon, SK, Canada.,University of Saskatchewan College of Medicine, Saskatoon, SK, Canada
| | - Roberta Melis
- ARUP Institute for Clinical and Experimental Pathology, Salt Lake City, UT
| | - Gwendolyn A McMillin
- ARUP Institute for Clinical and Experimental Pathology, Salt Lake City, UT.,Department of Pathology, University of Utah Health Sciences Center, Salt Lake City, UT
| | - Kamisha L Johnson-Davis
- ARUP Institute for Clinical and Experimental Pathology, Salt Lake City, UT; .,Department of Pathology, University of Utah Health Sciences Center, Salt Lake City, UT
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Zarca K, Durand-Zaleski I, Loriot MA, Chatellier G, Pallet N. Modeling the Outcome of Systematic TPMT Genotyping or Phenotyping Before Azathioprine Prescription: A Cost-Effectiveness Analysis. Mol Diagn Ther 2019; 23:429-438. [PMID: 30963516 DOI: 10.1007/s40291-019-00398-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Thiopurine S-methyltransferase (TPMT) testing, either by genotyping or phenotyping, can reduce the incidence of adverse severe myelotoxicity episodes induced by azathioprine. The comparative cost-effectiveness of TPMT genotyping and phenotyping are not known. OBJECTIVE Our aim was to assess the cost-effectiveness of phenotyping-based dosing of TPMT activity, genotyping-based screening and no screening (reference) for patients treated with azathioprine. METHODS A decision tree was built to compare the conventional weight-based dosing strategy with phenotyping and with genotyping using a micro-simulation model of patients with inflammatory bowel disease from the perspective of the French health care system. The time horizon was set up as 1 year. Only direct medical costs were used. Data used were obtained from previous reports, except for screening test and admission costs, which were from real cases. The main outcome was the cost-effectiveness ratios, with an effectiveness criterion of one averted severe myelotoxicity episode. RESULTS The total expected cost of the no screening strategy was €409/patient, the total expected cost of the phenotyping strategy was €427/patient, and the total expected cost of the genotyping strategy was €476/patient. The incremental cost-effectiveness ratio was €2602/severe myelotoxicity averted in using the phenotyping strategy, and €11,244/severe myelotoxicity averted in the genotyping strategy compared to the no screening strategy. At prevalence rates of severe myelotoxicity > 1%, phenotyping dominated genotyping and conventional strategies. CONCLUSION The phenotype-based strategy to screen for TPMT deficiency dominates (cheaper and more effective) the genotype-based screening strategy in France. Phenotype-based screening dominates no screening in populations with a prevalence of severe myelosuppression due to azathioprine of > 1%.
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Affiliation(s)
- Kevin Zarca
- Assistance Publique-Hôpitaux de Paris, DRCI-URC Eco Ile-de-France (AP-HP), Paris, France.,Assistance Publique-Hôpitaux de Paris, service de santé publique, Henri Mondor-Albert-Chenevier, Créteil, France
| | - Isabelle Durand-Zaleski
- Assistance Publique-Hôpitaux de Paris, DRCI-URC Eco Ile-de-France (AP-HP), Paris, France.,Assistance Publique-Hôpitaux de Paris, service de santé publique, Henri Mondor-Albert-Chenevier, Créteil, France
| | - Marie-Anne Loriot
- Service de Biochimie, Hôpital Européen Georges Pompidou, Assistance Publique-Hôpitaux de Paris, Université Paris Descates, 20, rue Leblanc, 75015, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Gilles Chatellier
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France.,Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges-Pompidou, Unité de Recherche Clinique, Paris, France.,Centre d'Investigation Clinique 1418 (CIC1418), Paris, France
| | - Nicolas Pallet
- Service de Biochimie, Hôpital Européen Georges Pompidou, Assistance Publique-Hôpitaux de Paris, Université Paris Descates, 20, rue Leblanc, 75015, Paris, France. .,Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
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Azathioprine Biotransformation in Young Patients with Inflammatory Bowel Disease: Contribution of Glutathione-S Transferase M1 and A1 Variants. Genes (Basel) 2019; 10:genes10040277. [PMID: 30987408 PMCID: PMC6523194 DOI: 10.3390/genes10040277] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 04/01/2019] [Accepted: 04/01/2019] [Indexed: 12/11/2022] Open
Abstract
The contribution of candidate genetic variants involved in azathioprine biotransformation on azathioprine efficacy and pharmacokinetics in 111 young patients with inflammatory bowel disease was evaluated. Azathioprine doses, metabolites thioguanine-nucleotides (TGN) and methylmercaptopurine-nucleotides (MMPN) and clinical effects were assessed after at least 3 months of therapy. Clinical efficacy was defined as disease activity score below 10. Candidate genetic variants (TPMT rs1142345, rs1800460, rs1800462, GSTA1 rs3957357, GSTM1, and GSTT1 deletion) were determined by polymerase chain reaction (PCR) assays and pyrosequencing. Statistical analysis was performed using linear mixed effects models for the association between the candidate variants and the pharmacological variables (azathioprine doses and metabolites). Azathioprine metabolites were measured in 257 samples (median 2 per patient, inter-quartile range IQR 1-3). Clinical efficacy at the first evaluation available resulted better in ulcerative colitis than in Crohn’s disease patients (88.0% versus 52.5% responders, p = 0.0003, linear mixed effect model, LME). TGN concentration and the ratio TGN/dose at the first evaluation were significantly higher in responder. TPMT rs1142345 variant (4.8% of patients) was associated with increased TGN (LME p = 0.0042), TGN/dose ratio (LME p < 0.0001), decreased azathioprine dose (LME p = 0.0087), and MMPN (LME p = 0.0011). GSTM1 deletion (58.1% of patients) was associated with a 18.5% decrease in TGN/dose ratio (LME p = 0.041) and 30% decrease in clinical efficacy (LME p = 0.0031). GSTA1 variant (12.8% of patients) showed a trend (p = 0.046, LME) for an association with decreased clinical efficacy; however, no significant effect on azathioprine pharmacokinetics could be detected. In conclusion, GSTs variants are associated with azathioprine efficacy and pharmacokinetics.
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11
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Rucci F, Cigoli MS, Marini V, Fucile C, Mattioli F, Robbiano L, Cavallari U, Scaglione F, Perno CF, Penco S, Marocchi A. Combined evaluation of genotype and phenotype of thiopurine S-methyltransferase (TPMT) in the clinical management of patients in chronic therapy with azathioprine. Drug Metab Pers Ther 2019; 34:dmpt-2018-0037. [PMID: 30840585 DOI: 10.1515/dmpt-2018-0037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 01/29/2019] [Indexed: 06/09/2023]
Abstract
Background The thiopurine S-methyltransferase (TPMT)/azathioprine (AZA) gene-drug pair is one of the most well-known pharmacogenetic markers. Despite this, few studies investigated the implementation of TPMT testing and the combined evaluation of genotype and phenotype in multidisciplinary clinical settings where patients are undergoing chronic therapy with AZA. Methods A total of 356 AZA-treated patients for chronic autoimmune diseases were enrolled. DNA was isolated from whole blood and the samples were analyzed for the c.460G>A and c.719A>G variants by the restriction fragment length polymorphism (RFLP) technique and sequenced for the c.238G>C variant. The TPMT enzyme activity was determined in erythrocytes by a high-performance liquid chromatography (HPLC) assay. Results All the patients enrolled were genotyped while the TPMT enzyme activity was assessed in 41 patients. Clinical information was available on 181 patients. We found no significant difference in the odds of having adverse drug reactions (ADRs) in wild-type patients and variant allele carriers, but the latter had an extra risk of experiencing hematologically adverse events. The enzyme activity was significantly associated to genotype. Conclusions TPMT variant allele carriers have an extra risk of experiencing hematologically adverse events compared to wild-type patients. Interestingly, only two out of 30 (6.6%) patients had discordant results between genotype, phenotype and onset of ADRs.
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Affiliation(s)
- Francesco Rucci
- Department of Laboratory Medicine, Medical Genetics, ASST Niguarda Hospital, Piazza Ospedale Maggiore, 3-20162 - Milan, Italy, Tel. +39 0264442803
- University of Milan, Department of Oncology and Onco-Hematology, Postgraduate School of Clinical Pharmacology and Toxicology, Milan, Italy
| | - Maria Sole Cigoli
- Department of Laboratory Medicine, Medical Genetics, ASST Niguarda Hospital, Milan, Italy
| | - Valeria Marini
- Department of Internal Medicine, University of Genova, Genova, Italy
| | - Carmen Fucile
- Department of Internal Medicine, University of Genova, Genova, Italy
| | | | - Luigi Robbiano
- Department of Internal Medicine, University of Genova, Genova, Italy
| | - Ugo Cavallari
- Department of Laboratory Medicine, Medical Genetics, ASST Niguarda Hospital, Milan, Italy
| | - Francesco Scaglione
- University of Milan, Department of Oncology and Onco-Hematology, Postgraduate School of Clinical Pharmacology and Toxicology, Milan, Italy
| | - Carlo F Perno
- Department of Laboratory Medicine, ASST Niguarda Hospital, Milan, Italy
| | - Silvana Penco
- Department of Laboratory Medicine, Medical Genetics, ASST Niguarda Hospital, Milan, Italy
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12
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Adehin A, Bolaji OO. Thiopurine S-methyltransferase activity in Nigerians: phenotypes and activity reference values. BMC Res Notes 2018; 11:129. [PMID: 29444714 PMCID: PMC5813413 DOI: 10.1186/s13104-018-3237-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Accepted: 02/06/2018] [Indexed: 11/21/2022] Open
Abstract
Objectives This study assessed the activity of thiopurine S-methyltransferase (TPMT) in Nigerians with a view to providing data on susceptibility to thiopurine toxicity, and as well generate reference activity values for clinical use. Results TPMT activity, expressed as the amount of 6MMP in ng/mL after 1 h incubation at 37 °C per haemoglobin (U/g Hb), varied between 2.34 and 63.50 U/g Hb in the study population. Poor metabolic phenotypes, characterised by an activity values below 8.41 U/g Hb, were observed in 20% of the study subjects. Intermediate metabolizers had activity values between 8.41 and 16.13 U/g Hb. Fast and very fast metabolizers were characterised by activity values of 16.20–56.22 and > 56.22 U/g Hb, respectively. These findings suggest that a potentially huge discordance between TPMT phenotype and genotype exist in Nigerians, and emphasizes the superiority of a prior determination of TPMT metabolic phenotype in ensuring the safety of thiopurine drug administration in the population.
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Affiliation(s)
- Ayorinde Adehin
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria. .,Institute of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou, Guangdong Province, China.
| | - Oluseye O Bolaji
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria
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13
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Alsous M, Yousef AM, Abdel Jalil M, Zawiah M, Yacoub S, Momani D, Gharabli A, Omar S, Rihani R. Genetic Polymorphism of Thiopurine S-methyltransferase in Children with Acute Lymphoblastic Leukemia in Jordan. Asian Pac J Cancer Prev 2018; 19:199-205. [PMID: 29373914 PMCID: PMC5844618 DOI: 10.22034/apjcp.2018.19.1.199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Background and Aims: It has been demonstrated that homozygote and heterozygote mutant allele carriers for thiopurine S-methyltransferase (TPMT) are at high risk of developing myelosuppression after receiving standard doses of 6-mercaptopurine (6-MP). The aim of this study was to determine the frequency of TPMT deficient alleles in children with acute lymphoblastic leukemia (ALL) in Jordan and to compare it with other ethnic groups. Methods: We included 52 ALL childhood cases from King Hussein Cancer Research Center in Jordan. Genotyping of the rs1800460, rs1800462, and rs1142345 SNPs was performed by polymerase chain reaction (PCR) followed by sequencing. Comparisons were made with historical data for controls and for both volunteers and cases from other middle-eastern countries. Results: Mutant TPMT alleles were present in 3.8% (2/52) of patients. Allelic frequencies were 1.0% for both TPMT*B and TPMT*C. None of the patients were heterozygous or homozygous for TPMT*3A or TPMT *2. We did not find statistically significant differences in the distribution of mutant alleles between Jordan and other middle-eastern countries for both healthy volunteers or ALL patients. Conclusions: The overall frequency of TPMT mutant alleles was low and did not exhibit differences compared to other middle-eastern countries, including Jordanian studies assessing TPMT mutant alleles in healthy volunteers. The current results question the value of TPMT genotyping in the Jordanian population.
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Affiliation(s)
- Mervat Alsous
- Department of Clinical Pharmacy and Therapeutics, Faculty of Pharmacy, Applied Science Private University, Amman, Jordan.
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Multicentric Case-Control Study on Azathioprine Dose and Pharmacokinetics in Early-onset Pediatric Inflammatory Bowel Disease. Inflamm Bowel Dis 2017; 23:628-634. [PMID: 28296824 DOI: 10.1097/mib.0000000000001051] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND Early-onset inflammatory bowel disease (IBD) is generally aggressive, with a high probability of complications and need of surgery. Despite the introduction of highly effective biological drugs, treatment with azathioprine continues to be important even for early-onset IBD; however, in these patients azathioprine response seems to be reduced. This study evaluated azathioprine doses, metabolite concentrations, and their associations with patients' age in children with IBD treated at 6 tertiary pediatric referral centers. METHODS Azathioprine doses, metabolites, and clinical effects were assessed after at least 3 months of therapy in 17 early-onset (age < 6 yr, cases) and 51 nonearly-onset (aged > 12 and <18 yrs, controls) patients with IBD. Azathioprine dose was titrated on therapeutic efficacy (response and adverse effects). Azathioprine metabolites and thiopurine methyltransferase activity were determined by high-performance liquid chromatography with ultra violet-vis detection (HPLC-UV) methods. RESULTS Frequency of patients in remission was similar among early-onset and control groups, respectively (82% and 84%, P value = 0.72). Early-onset patients required higher doses of azathioprine (median 2.7 versus 2.0 mg·kg·d, P value = 1.1 × 10). Different doses resulted in comparable azathioprine active thioguanine nucleotide metabolite concentrations (median 263 versus 366 pmol/8 × 10 erythrocytes, P value = 0.41) and methylmercaptopurine nucleotide concentrations (median 1455 versus 1532 pmol/8 × 10 erythrocytes, P value = 0.60). Lower ratios between thioguanine nucleotide metabolites and azathioprine doses were found in early-onset patients (median 98 versus 184 pmol/8 × 10 erythrocytes·mg·kg·d, P value = 0.017). Interestingly, early-onset patients presented also higher thiopurine methyltransferase activity (median 476 versus 350 nmol methylmercaptopurine/mg hemoglobin/h, P-value = 0.046). CONCLUSIONS This study demonstrated that patients with early-onset IBD present increased inactivating azathioprine metabolism, likely because of elevated activity of the enzyme thiopurine methyltransferase.
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Ma ALT, Bale G, Aitkenhead H, Marks SD. Measuring Erythrocyte Thiopurine Methyltransferase Activity in Children-Is It Helpful? J Pediatr 2016; 179:216-218. [PMID: 27640357 DOI: 10.1016/j.jpeds.2016.08.073] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 08/17/2016] [Accepted: 08/22/2016] [Indexed: 01/13/2023]
Abstract
OBJECTIVE To assess the profile of thiopurine transmethyltransferase (TPMT) enzyme activities in children and discuss the utility of measuring TPMT levels before commencing azathioprine therapy. STUDY DESIGN Retrospective study in a single pediatric center of all patients who had TPMT enzyme assay measured during a 3-year period before the start of azathioprine therapy. Patients' TPMT enzyme activities were classified as normal (26-50 pmol/h/mgHb), intermediate (10-25 pmol/h/mgHb), and deficient (<10 pmol/h/mgHb). Medical and electronic prescribing records were studied, with records of patients' demographic data, diagnoses, dosages, and adverse drug reactions monitored. RESULTS A total of 228 (45% female) patients ages 1-18 years (median 10 years) were tested for TPMT activity. They were all subsequently commenced on azathioprine. Erythrocyte TPMT activities were 14-76 (median 33.7) pmol/h/mgHb with 88% and 12% of patient having normal and intermediate activity respectively (none were deficient). The initial prescribed dosage of azathioprine was 0.7-3.5 (median 2.0) mg/kg/day. Only 2 patients developed mild neutropenia and required reduction of azathioprine dosage. CONCLUSION This large cohort study demonstrates that the majority of pediatric patients had normal TMPT activities. We would recommend close monitoring of full blood counts after instituting azathioprine therapy but would question the cost-effectiveness of pretreatment TPMT activity in pediatric practice.
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Affiliation(s)
- Alison L T Ma
- Department of Pediatric Nephrology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom.
| | - Gregory Bale
- Department of Pharmacy, Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
| | - Helen Aitkenhead
- Department of Chemical Pathology, Great Ormond Street Hospital for Children National Health Service (NHS) Foundation Trust, London, United Kingdom
| | - Stephen D Marks
- Department of Pediatric Nephrology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
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16
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Liu C, Yang W, Pei D, Cheng C, Smith C, Landier W, Hageman L, Chen Y, Yang JJ, Crews KR, Kornegay N, Karol SE, Wong FL, Jeha S, Sandlund JT, Ribeiro RC, Rubnitz JE, Metzger ML, Pui CH, Evans WE, Bhatia S, Relling MV. Genomewide Approach Validates Thiopurine Methyltransferase Activity Is a Monogenic Pharmacogenomic Trait. Clin Pharmacol Ther 2016; 101:373-381. [PMID: 27564568 DOI: 10.1002/cpt.463] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 07/26/2016] [Accepted: 08/23/2016] [Indexed: 12/11/2022]
Abstract
We performed a genomewide association study (GWAS) of primary erythrocyte thiopurine S-methyltransferase (TPMT) activity in children with leukemia (n = 1,026). Adjusting for age and ancestry, TPMT was the only gene that reached genomewide significance (top hit rs1142345 or 719A>G; P = 8.6 × 10-61 ). Additional genetic variants (in addition to the three single-nucleotide polymorphisms [SNPs], rs1800462, rs1800460, and rs1142345, defining TPMT clinical genotype) did not significantly improve classification accuracy for TPMT phenotype. Clinical mercaptopurine tolerability in 839 patients was related to TPMT clinical genotype (P = 2.4 × 10-11 ). Using 177 lymphoblastoid cell lines (LCLs), there were 251 SNPs ranked higher than the top TPMT SNP (rs1142345; P = 6.8 × 10-5 ), revealing a limitation of LCLs for pharmacogenomic discovery. In a GWAS, TPMT activity in patients behaves as a monogenic trait, further bolstering the utility of TPMT genetic testing in the clinic.
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Affiliation(s)
- C Liu
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - W Yang
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - D Pei
- Department of Biostatistics, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - C Cheng
- Department of Biostatistics, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - C Smith
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - W Landier
- School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - L Hageman
- School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Y Chen
- School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - J J Yang
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - K R Crews
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - N Kornegay
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - S E Karol
- Department of Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - F L Wong
- Department of Population Sciences, City of Hope, Duarte, California, USA
| | - S Jeha
- Department of Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - J T Sandlund
- Department of Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - R C Ribeiro
- Department of Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - J E Rubnitz
- Department of Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - M L Metzger
- Department of Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - C-H Pui
- Department of Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - W E Evans
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - S Bhatia
- School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - M V Relling
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
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Mlakar V, Huezo-Diaz Curtis P, Satyanarayana Uppugunduri CR, Krajinovic M, Ansari M. Pharmacogenomics in Pediatric Oncology: Review of Gene-Drug Associations for Clinical Use. Int J Mol Sci 2016; 17:ijms17091502. [PMID: 27618021 PMCID: PMC5037779 DOI: 10.3390/ijms17091502] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 08/02/2016] [Accepted: 08/15/2016] [Indexed: 02/07/2023] Open
Abstract
During the 3rd congress of the European Society of Pharmacogenomics and Personalised Therapy (ESPT) in Budapest in 2015, a preliminary meeting was held aimed at establishing a pediatric individualized treatment in oncology and hematology committees. The main purpose was to facilitate the transfer and harmonization of pharmacogenetic testing from research into clinics, to bring together basic and translational research and to educate health professionals throughout Europe. The objective of this review was to provide the attendees of the meeting as well as the larger scientific community an insight into the compiled evidence regarding current pharmacogenomics knowledge in pediatric oncology. This preliminary evaluation will help steer the committee’s work and should give the reader an idea at which stage researchers and clinicians are, in terms of personalizing medicine for children with cancer. From the evidence presented here, future recommendations to achieve this goal will also be suggested.
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Affiliation(s)
- Vid Mlakar
- Cansearch Research Laboratory, Geneva University Medical School, Avenue de la Roseraie 64, 1205 Geneva, Switzerland.
| | - Patricia Huezo-Diaz Curtis
- Cansearch Research Laboratory, Geneva University Medical School, Avenue de la Roseraie 64, 1205 Geneva, Switzerland.
| | | | - Maja Krajinovic
- Charles-Bruneau Cancer Center, Centre hospitalier universitaire Sainte-Justine, 4515 Rue de Rouen, Montreal, QC H1V 1H1, Canada.
- Department of Pediatrics, University of Montreal, 2900 Boulevard Edouard-Montpetit, Montreal, QC H3T 1J4, Canada.
- Department of Pharmacology, Faculty of Medicine, University of Montreal, 2900 Boulevard Edouard-Montpetit, Montreal, QC H3T 1J4, Canada.
| | - Marc Ansari
- Cansearch Research Laboratory, Geneva University Medical School, Avenue de la Roseraie 64, 1205 Geneva, Switzerland.
- Pediatric Department, Onco-Hematology Unit, Geneva University Hospital, Rue Willy-Donzé 6, 1205 Geneva, Switzerland.
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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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20
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El-Rashedy FH, Ragab SM, Dawood AA, Temraz SA. Clinical implication of thiopurine methyltransferase polymorphism in children with acute lymphoblastic leukemia: A preliminary Egyptian study. Indian J Med Paediatr Oncol 2016; 36:265-70. [PMID: 26811598 PMCID: PMC4711227 DOI: 10.4103/0971-5851.171553] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Background: 6-mercaptopurine (6-MP) is an essential component of pediatric acute lymphoblastic leukemia (ALL) maintenance therapy. Individual variability in this drug-related toxicity could be attributed in part to genetic polymorphism thiopurine methyltransferase (TPMT). Aim: To investigate the frequency of common TPMT polymorphisms in a cohort of Egyptian children with ALL and the possible relation between these polymorphisms and 6-MP with short-term complications. Materials and Methods: This study included 25 children. Data related to 6-MP toxicity during the maintenance phase were collected from the patients’ files. DNA was isolated and genotyping for TPMT G460A, and A719G mutations were performed by polymerase chain reaction-restriction fragment length polymorphism. Results: Twenty (80%) of the included 25 patients had a polymorphic TPMT allele. TPMT*3A was the most frequent (14/25, 56%), 8 patients were homozygous and 6 were heterozygous. TPMT*3C mutant allele was found in 4 patients (16%) in the heterozygous state while 2 patients (8%) were found to be heterozygous for TPMT*3B mutant allele. TPMT mutant patients, especially homozygous, were at greater risk of 6-MP hematological toxicity without significant difference regarding hepatic toxicity. Conclusions: TPMT polymorphism was common among the studied group and was associated with increased risk of drug toxicity. A population-based multi-center study is required to confirm our results.
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Affiliation(s)
- Farida H El-Rashedy
- Department of Pediatrics, Faculty of Medicine, Menoufia University, Shebeen El-Kom, Menoufia, Egypt
| | - Seham Mohammed Ragab
- Department of Pediatrics, Faculty of Medicine, Menoufia University, Shebeen El-Kom, Menoufia, Egypt
| | - Ashraf A Dawood
- Department of Biochemistry, Faculty of Medicine, Menoufia University, Shebeen El-Kom, Menoufia, Egypt
| | - Shaymaa A Temraz
- Department of Pediatrics, Faculty of Medicine, Menoufia University, Shebeen El-Kom, Menoufia, Egypt
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Kotur N, Dokmanovic L, Janic D, Stankovic B, Krstovski N, Tosic N, Katsila T, Patrinos GP, Zukic B, Pavlovic S. TPMT gene expression is increased during maintenance therapy in childhood acute lymphoblastic leukemia patients in a TPMT gene promoter variable number of tandem repeat-dependent manner. Pharmacogenomics 2015; 16:1701-12. [PMID: 26411491 DOI: 10.2217/pgs.15.109] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
AIMS 6-mercaptopurine influences in vitro TPMT gene expression in a TPMT promoter variable number of tandem repeats (VNTR)-dependent manner. We studied TPMT expression following 6-mercaptopurine and methotrexate administration in childhood acute lymphoblastic leukemia (ALL) patients and the pharmacogenomic potential of the VNTR architecture. MATERIALS & METHODS TPMT gene expression was determined in childhood ALL patients at diagnosis (n = 57) and during the maintenance therapy (n = 27). RESULTS A threefold increase of TPMT gene expression was obtained during maintenance therapy, modulated by the architecture of the VNTR region. CONCLUSION The TPMT promoter genetic variants need to be considered at the very beginning of the maintenance therapy for childhood ALL patients. The TPMT promoter VNTR region may serve as a pharmacogenomic biomarker when introducing thiopurine therapy.
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Affiliation(s)
- Nikola Kotur
- Laboratory for Molecular Biomedicine, Institute of Molecular Genetics & Genetic Engineering, University of Belgrade, Serbia
| | - Lidija Dokmanovic
- University Children's Hospital, School of Medicine, University of Belgrade, Serbia
| | - Dragana Janic
- University Children's Hospital, School of Medicine, University of Belgrade, Serbia
| | - Biljana Stankovic
- Laboratory for Molecular Biomedicine, Institute of Molecular Genetics & Genetic Engineering, University of Belgrade, Serbia
| | - Nada Krstovski
- University Children's Hospital, School of Medicine, University of Belgrade, Serbia
| | - Natasa Tosic
- Laboratory for Molecular Biomedicine, Institute of Molecular Genetics & Genetic Engineering, University of Belgrade, Serbia
| | - Theodora Katsila
- Department of Pharmacy, University of Patras, School of Health Sciences, Patras, Greece
| | - George P Patrinos
- Department of Pharmacy, University of Patras, School of Health Sciences, Patras, Greece
| | - Branka Zukic
- Laboratory for Molecular Biomedicine, Institute of Molecular Genetics & Genetic Engineering, University of Belgrade, Serbia
| | - Sonja Pavlovic
- Laboratory for Molecular Biomedicine, Institute of Molecular Genetics & Genetic Engineering, University of Belgrade, Serbia
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Chouchana L, Narjoz C, Roche D, Golmard JL, Pineau B, Chatellier G, Beaune P, Loriot MA. Interindividual variability in TPMT enzyme activity: 10 years of experience with thiopurine pharmacogenetics and therapeutic drug monitoring. Pharmacogenomics 2015; 15:745-57. [PMID: 24897283 DOI: 10.2217/pgs.14.32] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND & AIMS TPMT activity and metabolite determination (6-thioguanine nucleotides [6-TGN] and 6-methylmercaptopurine nucleotides [6-MMPN]) remain controversial during thiopurine management. This study assessed associations between patient characteristics and TPMT activity, and their impact on metabolite levels. PATIENTS & METHODS A retrospective review of the laboratory database from a French university hospital identified 7360 patients referred for TPMT phenotype/genotype determination, and/or for 6-TGN/6-MMPN monitoring. RESULTS Four TPMT phenotypes were identified according to TPMT activity distribution: low, intermediate, normal/high and very high. Based on 6775 assays, 6-TGN concentrations were 1.6-fold higher in TPMT-deficient patients compared with TPMT-normal patients. Azathioprine dose and TPMT genotype were significant predictors of metabolite levels. Furthermore, 6-MMPN and 6-MMPN: 6-TGN ratios were, respectively, 1.6- and 2.2-fold higher in females than in males, despite similar TPMT, 6-TGN and azathioprine doses. An unfavorable ratio (≥20) was associated with a slightly higher TPMT activity. CONCLUSION These results illustrate the usefulness of pharmacogenomics and metabolite measurement to improve the identification of noncompliance and patients at high risk for toxicity or therapeutic resistance. Original submitted 13 November 2013; Revision submitted 30 January 2014.
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Lennard L. Implementation of TPMT testing. Br J Clin Pharmacol 2014; 77:704-14. [PMID: 23962279 DOI: 10.1111/bcp.12226] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 07/23/2013] [Indexed: 12/21/2022] Open
Abstract
The activity of the enzyme thiopurine methyltransferase (TPMT) is regulated by a common genetic polymorphism. One in 300 individuals lack enzyme activity and 11% are heterozygous for a variant low activity allele and have an intermediate activity. The thiopurine drugs azathioprine, mercaptopurine and thioguanine are substrates for TPMT; these drugs exhibit well documented myelosuppressive effects on haematopoietic cells and have a track record of idiosyncratic drug reactions. The development of severe bone marrow toxicity, in patients taking standard doses of thiopurine drugs, is associated with TPMT deficiency whilst the TPMT heterozygote is at an increased risk of developing myelosuppression. Factors influencing TPMT enzyme activity, as measured in the surrogate red blood cell, are discussed in this review to enable an appreciation of why concordance between TPMT genotype and phenotype is not 100%. This is particularly important for lower/intermediate TPMT activities to avoid misclassification of TPMT status. TPMT testing is now widely available in routine service laboratories. The British National Formulary suggests TPMT testing before starting thiopurine drugs. Dermatologists were quick to adopt routine TPMT testing whilst gastroenterologists do not specifically recommend TPMT screening. TPMT testing is mandatory prior to the use of mercaptopurine in childhood leukaemia. Thiopurine drug dose and other treatment related influences on cell counts explain some of the differing recommendations between clinical specialities. TPMT testing is cost-effective and the major role is in the identification of the TPMT deficient individual prior to the start of thiopurine drugs.
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Affiliation(s)
- Lynne Lennard
- Clinical Pharmacology Unit, Department of Human Metabolism, University of Sheffield, Sheffield, UK
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Stevens A, De Leonibus C, Hanson D, Whatmore A, Murray P, Donn R, Meyer S, Chatelain P, Clayton P. Pediatric perspective on pharmacogenomics. Pharmacogenomics 2014; 14:1889-905. [PMID: 24236488 DOI: 10.2217/pgs.13.193] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The advances in high-throughput genomic technologies have improved the understanding of disease pathophysiology and have allowed a better characterization of drug response and toxicity based on individual genetic make up. Pharmacogenomics is being recognized as a valid approach used to identify patients who are more likely to respond to medication, or those in whom there is a high probability of developing severe adverse drug reactions. An increasing number of pharmacogenomic studies are being published, most include only adults. A few studies have shown the impact of pharmacogenomics in pediatrics, highlighting a key difference between children and adults, which is the contribution of developmental changes to therapeutic responses across different age groups. This review focuses on pharmacogenomic research in pediatrics, providing examples from common pediatric conditions and emphasizing their developmental context.
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Affiliation(s)
- Adam Stevens
- Institute of Human Development, Medical & Human Sciences, University of Manchester & Royal Manchester Children's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, 5th Floor Research, Oxford Road, Manchester, M13 9WL, UK
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Lennard L, Cartwright CS, Wade R, Richards SM, Vora A. Thiopurine methyltransferase genotype-phenotype discordance and thiopurine active metabolite formation in childhood acute lymphoblastic leukaemia. Br J Clin Pharmacol 2014; 76:125-36. [PMID: 23252716 DOI: 10.1111/bcp.12066] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 12/09/2012] [Indexed: 12/14/2022] Open
Abstract
AIMS In children with acute lymphoblastic leukaemia (ALL) bone marrow activity can influence red blood cell (RBC) kinetics, the surrogate tissue for thiopurine methyltransferase (TPMT) measurements. The aim of this study was to investigate TPMT phenotype-genotype concordance in ALL, and the influence of TPMT on thiopurine metabolite formation. METHODS We measured TPMT (activity, as units ml(-1) packed RBCs and genotype) at diagnosis (n = 1150) and TPMT and thioguanine nucleotide (TGN) and methylmercaptopurine nucleotide (MeMPN) metabolites (pmol/8 × 10(8) RBCs) during chemotherapy (n = 1131) in children randomized to thioguanine or mercaptopurine on the United Kingdom trial ALL97. RESULTS Median TPMT activity at diagnosis (8.5 units) was significantly lower than during chemotherapy (13.8 units, median difference 5.1 units, 95% confidence interval (CI) 4.8, 5.4, P < 0.0001). At diagnosis genotype-phenotype was discordant. During chemotherapy the overall concordance was 92%, but this fell to 55% in the intermediate activity cohort (45% had wild-type genotypes). For both thiopurines TGN concentrations differed by TPMT status. For mercaptopurine, median TGNs were higher in TPMT heterozygous genotype (754 pmol) than wild-type (360 pmol) patients (median difference 406 pmol, 95% CI 332, 478, P < 0.0001), whilst median MeMPNs, products of the TPMT reaction, were higher in wild-type (10 650 pmol) than heterozygous patients (3868 pmol) (P < 0.0001). In TPMT intermediate activity patients with a wild-type genotype, TGN (median 366 pmol) and MeMPN (median 8590 pmol) concentrations were similar to those in wild-type, high activity patients. CONCLUSIONS In childhood ALL, TPMT activity should not be used to predict heterozygosity particularly in blood samples obtained at disease diagnosis. Genotype is a better predictor of TGN accumulation during chemotherapy.
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Affiliation(s)
- Lynne Lennard
- Clinical Pharmacology Unit, Department of Human Metabolism, University of Sheffield, Sheffield, UK.
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van Egmond R, Barclay ML, Chin PKL, Sies CW, Florkowski CM. Preanalytical stringency: what factors may confound interpretation of thiopurine S-methyl transferase enzyme activity? Ann Clin Biochem 2013; 50:479-84. [DOI: 10.1177/0004563212474558] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background Measurement of red blood cell thiopurine S-methyl transferase (TPMT) enzyme activity before commencing thiopurine therapy is recommended to avoid severe bone marrow suppression in TPMT-deficient patients. Patient's samples go through preanalytical transportation and storage steps before measurement. We studied patient's TPMT activity sample data to assess the effect of preanalytical variables including transportation time. Methods A total of 8524 TPMT enzyme activity analyses were conducted from 2002 to 2010 in a single laboratory, with samples sent from seven centres throughout New Zealand. TPMT activity was correlated with time of arrival at the reference laboratory, patient gender and age and centre of sample collection. Results The 6348 (74%) selected TPMT measurements that fulfilled selection criteria ranged from 0 to 25.8 IU/mL. Median delay to sample analysis was 42 h. Median TPMT activity was significantly lower for all centres compared with the reference centre ( P < 0.001). Delay in sample arrival was significantly and independently correlated with TPMT enzyme activity (ANCOVA; P < 0.001), which showed a 0.011 (95% CI, 0.008–0.014) IU/mL decrease per extra hour of delay. After correcting for these data, one centre still had a significantly lower TPMT enzyme activity compared with the reference centre. Conclusions There was a significant negative correlation between TPMT enzyme activity and delay from sample collection to analysis. Transportation time is therefore an important preanalytical variable influencing TPMT activity. Samples from one centre had a lower TPMT activity after correcting for transportation delay, suggesting that other factors related to sample processing may also be relevant.
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Affiliation(s)
- Remco van Egmond
- Department of Clinical Pharmacology, Christchurch Hospital, Christchurch, New Zealand
| | - Murray L Barclay
- Department of Clinical Pharmacology, Christchurch Hospital, Christchurch, New Zealand
- Department of Gastroenterology, Christchurch Hospital, Christchurch, New Zealand
| | - Paul K L Chin
- Department of Clinical Pharmacology, Christchurch Hospital, Christchurch, New Zealand
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Garrido C, Santizo VG, Müllers P, Soriano DR, Avila GB, Dean M, Jimenez-Morales S. Frequency of thiopurine S-methyltransferase mutant alleles in indigenous and admixed Guatemalan patients with acute lymphoblastic leukemia. Med Oncol 2013; 30:474. [PMID: 23377985 DOI: 10.1007/s12032-013-0474-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Accepted: 01/08/2013] [Indexed: 12/11/2022]
Abstract
Thiopurine S-methyltransferase (TPMT) polymorphisms affect the enzyme's activity and are predictive for the efficacy and toxicity of thiopurine treatment of acute lymphoblastic leukemia (ALL), autoimmune diseases and organ transplants. Because inter-ethnic differences in the distribution of these polymorphisms have been documented, we sequenced the TMPT gene in 95 Guatemalans, yet identified no new alleles. We also determined the frequency of the TPMT 2, 3A, 3B and 3C alleles in 270 admixed and 177 indigenous pediatric patients with ALL and healthy subjects from Guatemala using TaqMan assays and DNA sequencing. Among the 447 subjects genotyped, 10.0 % of the ALL cases and 13.6 % of the healthy controls were heterozygous for one of the four TPMT variants screened. The genotype frequencies in ALL and control populations were 0.7 and 1.7 % for TPMT 1/ 2, 7.4 and 10 % for TPMT 1/3A, 0.3 and 0 % for TPMT 1/B, and 1.5 and 1.1 % for TPMT 1/C, respectively (p = 0.30). No statistically significant differences between admixed and indigenous ALL (p = 0.67) or controls (p = 0.41) groups were detected; however, 17 % of the admixed healthy group bore one TPMT mutant allele, and they have one of the highest reported frequencies of TPMT mutant allele carriers. Because of the clinical implications of these variants for therapeutic response, TPMT allele testing should be considered in all Guatemalan patients to reduce adverse side-effects from thiopurine drug treatments.
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Affiliation(s)
- Claudia Garrido
- Unidad Nacional de Oncología Pediátrica, Guatemala City, Guatemala
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Stocco G, De Iudicibus S, Cuzzoni E, Decorti G, Martelossi S, Ventura A. Letter: TPMT activity and age in IBD patients. Aliment Pharmacol Ther 2012; 35:966-7; author reply 967-9. [PMID: 22436044 DOI: 10.1111/j.1365-2036.2012.05027.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Larussa T, Suraci E, Lentini M, Nazionale I, Gallo L, Abenavoli L, Imeneo M, Costanzo FS, Cuda G, Luzza F. High prevalence of polymorphism and low activity of thiopurine methyltransferase in patients with inflammatory bowel disease. Eur J Intern Med 2012; 23:273-7. [PMID: 22385887 DOI: 10.1016/j.ejim.2011.12.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 12/03/2011] [Accepted: 12/08/2011] [Indexed: 01/30/2023]
Abstract
BACKGROUND Gene polymorphism of thiopurine methyltransferase (TPMT) correlates with decreased enzyme activity which determines a significant risk of adverse effect reactions (ADR) in patients treated with thiopurines. The aim of this study was to investigate TPMT genotype and phenotype status in patients with inflammatory bowel diseases (IBD). METHODS Fifty-one consecutive out-patients with IBD were genotyped for the following allelic variants: rs1800462 (referred as TPMT 2 allele), rs1800460 (referred as TPMT 3B allele), and 1142345 (referred as TPMT 3C allele). Red blood cell TPMT activity was measured using a competitive micro-well immunoassay for the semi-quantitative determination of TPMT activity in red blood cells (RBC) by means of a 6-MP substrate. RESULTS Polymorphism of TPMT was found in 5 out of 51 patients (10%; 95% CI 2%-18%), three heterozygous and two homozygous carriers. Six patients (11.8%; 95% CI 2.4%-19.5%) displayed very low, 12 (23.5%; 95% CI 11.4%-34.5%) intermediate, and 33 (64.7%; 95% CI 52%-78%) normal/high TPMT activity. There were no differences between TPMT genotype and phenotype groups according to age, type of disease, smoking, and chronic medications. A 71% (95% CI 61%-81%; κ=0.45) concordance rate was found between genotype and phenotype status. Six out of 27 (22%) current or past users of azathioprine developed ADR, with three (50%) displaying TPMT genotype and/or phenotype alterations. CONCLUSION Compared to the general population, IBD patients may have significantly higher prevalence of TPMT polymorphism and, even more, low activity. Phenotypic more than genotypic TPMT analysis could be useful to better manage IBD therapy with thiopurines.
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Affiliation(s)
- Tiziana Larussa
- Department of Health Science, University of Catanzaro "Magna Graecia", Catanzaro, Italy
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Román M, Cabaleiro T, Ochoa D, Novalbos J, Chaparro M, Gisbert JP, Abad-Santos F. Validation of a genotyping method for analysis of TPMT polymorphisms. Clin Ther 2012; 34:878-84. [PMID: 22421577 DOI: 10.1016/j.clinthera.2012.02.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/14/2012] [Indexed: 01/26/2023]
Abstract
BACKGROUND Thiopurine methyltransferase (TPMT) catalyzes the methylation of thiopurine drugs such as azathioprine and 6-mercaptopurine. Several mutations in the TPMT gene correlate with low enzyme activity and adverse effects such as myelotoxicity. Hence, genotyping TPMT makes it possible to identify patients at high risk for drug toxicity. OBJECTIVE The aim of this study was to validate a TPMT genotyping method by comparing it with a conventional polymerase chain reaction (PCR) approach. METHODS LightSNiP is a real-time PCR method for the detection of TPMT*2, *3B, and *3C without a sequencing step. We evaluated the frequencies of 3 TPMT alleles in 111 white adult patients by comparing genotyping by LightSNiP with conventional PCR (sequencing). RESULTS No differences were observed between conventional genotyping with sequencing and LightSNiP for *2, *3B, and *3C, suggesting the validity of this method. CONCLUSIONS Compared with the conventional PCR sequencing method, the data suggest that LightSNiP correctly detected the TPMT *2, *3B, and *3C in this select population.
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Affiliation(s)
- Manuel Román
- Clinical Pharmacology Service, Hospital Universitario de la Princesa, Instituto Teófilo Hernando, UAM, Instituto de Investigación Sanitaria Princesa (IP), Madrid, Spain
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Uppugunduri CRS, Ansari M. Influence of age, sex, and haplotypes of thiopurine methyltransferase (TPMT) gene on 6- mercaptopurine toxicity in children with acute lymphoblastic leukemia. Eur J Clin Pharmacol 2011; 68:887-8; author reply 885-6. [PMID: 22166935 DOI: 10.1007/s00228-011-1185-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Accepted: 11/22/2011] [Indexed: 10/14/2022]
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Thiopurine methyltransferase polymorphisms and mercaptopurine tolerance in Turkish children with acute lymphoblastic leukemia. Cancer Chemother Pharmacol 2011; 68:1155-9. [DOI: 10.1007/s00280-011-1599-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 02/28/2011] [Indexed: 12/22/2022]
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Dong XW, Zheng Q, Zhu MM, Tong JL, Ran ZH. Thiopurine S-methyltransferase polymorphisms and thiopurine toxicity in treatment of inflammatory bowel disease. World J Gastroenterol 2010; 16:3187-95. [PMID: 20593505 PMCID: PMC2896757 DOI: 10.3748/wjg.v16.i25.3187] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To evaluate the relationship between thiopurine S-methyltransferase (TPMT) polymorphisms and thiopurine-induced adverse drug reactions (ADRs) in inflammatory bowel disease (IBD).
METHODS: Eligible articles that compared the frequency of TPMT polymorphisms among thiopurine-tolerant and -intolerant adult IBD patients were included. Statistical analysis was performed with Review Manager 5.0. Sub-analysis/sensitivity analysis was also performed.
RESULTS: Nine studies that investigated a total of 1309 participants met our inclusion criteria. The incidence of TPMT gene mutation was increased 2.93-fold (95% CI: 1.68-5.09, P = 0.0001) and 5.93-fold (95% CI: 2.96-11.88, P < 0.00001), respectively, in IBD patients with thiopurine-induced overall ADRs and bone marrow toxicity (BMT), compared with controls. The OR for TPMT gene mutation in IBD patients with thiopurine-induced hepatotoxicity and pancreatitis was 1.51 (95% CI: 0.54-4.19, P = 0.43) and 1.02 (95% CI: 0.26-3.99, P = 0.98) vs controls, respectively.
CONCLUSION: This meta-analysis suggests that the TPMT polymorphisms are associated with thiopurine-induced overall ADRs and BMT, but not with hepatotoxicity and pancreatitis.
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Daperno M, Sostegni R, Canaparo R, Serpe L, Lavagna A, Crocellà L, Castagno F, Vernetto A, Rigazio C, Ercole E, D'Antico S, Pera A, Zara G, Rocca R. Prospective study of the effects of concomitant medications on thiopurine metabolism in inflammatory bowel disease. Aliment Pharmacol Ther 2009; 30:843-53. [PMID: 19650826 DOI: 10.1111/j.1365-2036.2009.04106.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Thiopurines are increasingly used in the treatment of inflammatory bowel disease (IBD), being the most common immunosuppressive therapy; however, potentially harmful interactions between thiopurines and other drugs (especially 5-aminosalicylic acid, 5-ASA) were described. AIM To explore potential interactions between thiopurines and concomitant medications. METHODS A total of 183 consecutive IBD patients were enrolled. Clinical characteristics and concomitant medications were recorded. Thiopurine metabolism was analysed with thiopurine S-methyl transferase (TPMT) genetic variants and enzyme activity assays. Comparisons were carried out with stratification of patients according to clinical characteristics and active treatments. RESULTS Based on TPMT genetics, 95% IBD patients were wild-type homozygous, the remaining being heterozygous. Median TPMT activity was 24.9 U/Hgb g (IQR 20.7-29.5). No difference in TPMT activity was noted according to 5-ASA exposure. IBD patients on thiopurines had higher TPMT activity levels, but no dose-effect was evident. No difference in TPMT activity was observed in 41 (63%) patients co-treated with 5-ASA. In patients on active thiopurines also, 6-TGN and 6-MMP levels were evaluated and no significant difference was observed based on co-medication. TPMT activity was independently associated only with thiopurines dose (P = 0.016). CONCLUSIONS Our data suggest the absence of significant interactions between thiopurines and 5-ASA.
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Affiliation(s)
- M Daperno
- Gastroenterology Division, A.O. Ordine Mauriziano, Torino, Italy.
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