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Ueda H, Narumi K, Asano S, Saito Y, Furugen A, Kobayashi M. Comparative study on the occurrence of adverse effects in the concomitant use of azathioprine and aldehyde oxidase inhibitors. Expert Opin Drug Saf 2024; 23:89-97. [PMID: 38097359 DOI: 10.1080/14740338.2023.2295976] [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: 06/15/2023] [Accepted: 11/28/2023] [Indexed: 12/19/2023]
Abstract
OBJECTIVES Aldehyde oxidase (AO) is a molybdenum-containing redox enzyme similar to xanthine oxidase that is involved in the thiopurine metabolism. This study investigated the effects of drug-drug interactions (DDIs) between azathioprine (AZA) and AO inhibitors on hematologic and hepatic disorders using the U.S. Food and Drug Administration Adverse Event Reporting System and the Japanese Adverse Drug Event Report database. METHODS The presence of DDI was assessed using the interaction signal scores (ISSs) calculated via the reporting odds ratios and 95% confidence intervals. The study used reports of 'azathioprine' as a suspect drug for adverse effects. AO inhibitors were selected based on previous in vitro reports. RESULTS Some drugs tested positive for ISSs in each database and type of adverse effect (hematologic or hepatic disorder) analysis. Among these drugs, chlorpromazine, clozapine, hydralazine, and quetiapine could inhibit AZA metabolism via AO, given the previously reported clinical blood concentration and inhibitory effects of each drug. CONCLUSION Concomitant use of AO inhibitors increased the signals for AZA-induced adverse effects. To date, no studies have evaluated the clinical importance of AO as a drug-metabolizing enzyme, and further in vitro and clinical research is needed to clarify the contribution of AO to the pharmacokinetics of thiopurines.
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Affiliation(s)
- Hinata Ueda
- Laboratory of Clinical Pharmaceutics & Therapeutics, Division of Pharmasciences, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Katsuya Narumi
- Laboratory of Clinical Pharmaceutics & Therapeutics, Division of Pharmasciences, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
- Education Research Center for Clinical Pharmacy, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Shuho Asano
- Laboratory of Clinical Pharmaceutics & Therapeutics, Division of Pharmasciences, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Yoshitaka Saito
- Department of Clinical Pharmaceutics & Therapeutics, Faculty of Pharmaceutical Sciences, Hokkaido University of Science, Sapporo, Japan
| | - Ayako Furugen
- Laboratory of Clinical Pharmaceutics & Therapeutics, Division of Pharmasciences, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Masaki Kobayashi
- Laboratory of Clinical Pharmaceutics & Therapeutics, Division of Pharmasciences, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
- Education Research Center for Clinical Pharmacy, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
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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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3
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Belhocine M, Mourad A, Chapdelaine A, Mansour AM, Troyanov Y, Doré M. Optimizing Thiopurine Therapy with a Xanthine Oxidase Inhibitor in Patients with Systemic Autoimmune Diseases: A Single-Centre Experience. Can J Hosp Pharm 2021; 74:361-369. [PMID: 34602624 DOI: 10.4212/cjhp.v74i4.3199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Background Thiopurines are a mainstay of therapy for autoimmune diseases. However, up to 20% to 30% of patients experience overproduction of the methylated metabolites, known as 6-MMP, to the detriment of the active metabolite, 6-thioguanine nucleotide (6-TGN). These patients, commonly referred to as "shunters", are predisposed to thiopurine resistance and hepatotoxicity. In patients with inflammatory bowel diseases, the combination of thiopurine with a xanthine oxidase inhibitor (XOI) is used to reverse this skewed metabolism and to prevent treatment failure or hepatotoxicity. Data on the use of this strategy for patients with other diseases are limited. Objectives To investigate and describe the use of thiopurine-XOI combination therapy in shunters with systemic autoimmune diseases. Methods Shunters treated in the study hospital between January 1, 2005, and December 31, 2015, were identified using the hospital's laboratory database, and clinical data were collected retrospectively. For each patient with optimization of thiopurine therapy, clinical and laboratory data were assessed over a 6-month period. Results Thirty-four patients were identified as shunters; for 14 of these patients, thiopurine therapy was optimized with an XOI. In these 14 patients, the median dose of azathioprine was reduced from 1.95 to 0.78 mg/kg with combination therapy. In addition, median 6-TGN level increased from 135 to 385 pmol/8 × 108 erythrocytes (p = 0.001); furthermore, 6-TGN levels rose to above 235 pmol/8 ×108 erythrocytes for 11 of the 14 patients. Conversely, the median 6-MMP level decreased from 6267 to 271 pmol/8 × 108 erythrocytes (p = 0.001). Except for a 12% increase in mean corpuscular volume, no clinically significant changes in blood count were recorded. Notable infections were reported in 3 patients, and 1 patient had to discontinue treatment because of cytopenia. After 6 months, median prednisone daily dose was reduced by 74%, from 16.7 mg to 4.4 mg (p = 0.005), and 4 patients had been weaned off corticosteroids. Of the 14 patients, 11 (79%) were in full remission, and 2 (14%) were in partial remission. Conclusion Optimizing thiopurine therapy with an XOI may be a safe and effective strategy for patients with systemic autoimmune diseases.
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Affiliation(s)
- Mériem Belhocine
- , MD, FRCPC, is an internal medicine specialist with Hôpital du Sacré-Coeur de Montréal, and a Clinical Professor of Medicine in the Faculty of Medicine, Université de Montréal, Montréal, Quebec
| | - Alissar Mourad
- , PharmD, MSc, was, at the time of this study, a PharmD student in the Faculty of Pharmacy, Université de Montréal, Montréal, Quebec. She has now graduated and is a pharmacist with the Centre intégré universitaire de santé et services sociaux du Centre-sud-de-l'Ile-de-Montréal, Montréal, Quebec
| | - Aurélie Chapdelaine
- , MD, FRCPC, is an internal medicine specialist with the Department of Medicine, Hôpital Notre-Dame, Montréal, Quebec
| | - Anne-Marie Mansour
- , MD, MSc, FRCPC, is an internal medicine specialist with the Department of Medicine, Hôpital du Sacré-Coeur de Montréal, and a Clinical Professor of Medicine with the Faculty of Medicine, Université de Montréal, Montréal, Quebec
| | - Yves Troyanov
- , MD, FRCPC, is a rheumatologist with the Department of Medicine, Hôpital du Sacré-Coeur de Montréal, and a Clinical Professor of Medicine with the Faculty of Medicine, Université de Montréal, Montréal, Quebec
| | - Maxime Doré
- , BSc, BPharm, MSc, is a Clinical Pharmacist with the Hôpital du Sacré-Coeur de Montréal, Montréal, Quebec
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Franca R, Braidotti S, Stocco G, Decorti G. Understanding thiopurine methyltransferase polymorphisms for the targeted treatment of hematologic malignancies. Expert Opin Drug Metab Toxicol 2021; 17:1187-1198. [PMID: 34452592 DOI: 10.1080/17425255.2021.1974398] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
INTRODUCTION Thiopurine methyltransferase (TPMT) catalyzes the S-methylation of thiopurines (mercaptopurine (MP) and tioguanine (TG)), chemotherapeutic agents used in the treatment of acute lymphoblastic leukemia (ALL). Polymorphisms in TPMT gene encode diminished activity enzyme, enhancing accumulation of active metabolites, and partially explaining the inter-individual differences in patients' clinical response. AREAS COVERED This review gives an overview on TPMT gene and function, and discusses the pharmacogenomic implications of TPMT variants in the prevention of severe thiopurine-induced hematological toxicities and the less known implication on TG-induced sinusoidal obstruction syndrome. Additional genetic and non-genetic factors impairing TPMT activity are considered. Literature search was done in PubMed for English articles published since1990, and on PharmGKB. EXPERT OPINION To titrate thiopurines safely and effectively, achieve the right degree of lymphotoxic effect and avoid excessive myelosuppression, the optimal management will combine a preemptive TPMT genotyping to establish a safe initial dose with a close phenotypic monitoring of TPMT activity and/or of active metabolites during long-term treatment. Compared to current ALL protocols, replacement of TG by MP during reinduction phase in TPMT heterozygotes and novel individualized TG regimens in maintenance for TPMT wild-type subjects could be investigated to improve outcomes while avoiding risk of severe hepatotoxicity.
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Affiliation(s)
- R Franca
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | - S Braidotti
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | - G Stocco
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - G Decorti
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy.,Institute for Maternal & Child Health (I.r.c.c.s) Burlo Garofolo, Trieste, Italy
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Jena A, Jha DK, Kumar-M P, Kasudhan KS, Kumar A, Sarwal D, Mishra S, Singh AK, Bhatia P, Patil A, Sharma V. Prevalence of polymorphisms in thiopurine metabolism and association with adverse outcomes: a South Asian region-specific systematic review and meta-analysis. Expert Rev Clin Pharmacol 2021; 14:491-501. [PMID: 33682590 DOI: 10.1080/17512433.2021.1900729] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Background: Prevalence and impact of thiopurine S-methyltransferase (TPMT) and Nudix hydrolase (NUDT15) minor allele frequencies in South Asian population is unclear.Methods: We searched PubMed and Embase with keywords-TPMT and NUDT15 combined with South Asian countries. We included studies reporting frequency of TPMT and NUDT15 polymorphisms. We estimated the pooled prevalence of TPMT and NUDT15 polymorphisms and their impact on pooled odds ratio of adverse events with thiopurines.Results: We included 26 studies in our analysis. The pooled prevalence of NUDT15 and TPMT polymorphisms was 16.5% (95% CI: 13.09-20.58) and 4.57% (95% CI: 3.66-5.68), respectively. In patients with adverse effects, the pooled prevalence of NUDT15 and TPMT polymorphism was 49.51% (95% C.I. 21.69-77.64) and 9.47% (95% C.I. 5.39-16.11), respectively. The odds ratio (OR) of adverse events with presence of TPMT polymorphisms was 3.65 (95% C.I., 1.43-9.28). The pooled OR for adverse events in presence of NUDT15 polymorphism was 12.63 (95% C.I., 3.68-43.26).Conclusion: NUDT15 were reported more frequently than the TPMT polymorphisms in South Asian population and were more frequently associated with adverse events. These findings may have implications for preemptive testing amongst South Asian population and immigrants prior to starting thiopurines.
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Affiliation(s)
- Anuraag Jena
- Department of Gastroenterology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Daya Krishna Jha
- Department of Gastroenterology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Praveen Kumar-M
- Department of Pharmacology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Kripa Shanker Kasudhan
- Department of Pharmacology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Ankit Kumar
- Department of Pharmacology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Dhruv Sarwal
- Government Medical College and hospital- Sector 32, Ex-intern, Chandigarh, India
| | - Shubhra Mishra
- Department of Gastroenterology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Anupam Kumar Singh
- Department of Gastroenterology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Prateek Bhatia
- Department of Pediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Amol Patil
- Department of Pharmacology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Vishal Sharma
- Department of Gastroenterology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
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Houwen JPA, Egberts ACG, de Boer A, van Maarseveen EM, Houwen RHJ, Lalmohamed A. Influence of allopurinol on thiopurine associated toxicity: A retrospective population-based cohort study. Br J Clin Pharmacol 2020; 87:2333-2340. [PMID: 33118191 PMCID: PMC8246992 DOI: 10.1111/bcp.14625] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 06/18/2020] [Accepted: 07/17/2020] [Indexed: 12/20/2022] Open
Abstract
Aims Thiopurines are important for treating inflammatory bowel disease, but are often discontinued due to adverse effects. Concomitant use of allopurinol might lower the risk of these unwanted effects, but large studies in the general population are lacking. The aims of this study were to evaluate rates of hepatotoxicity, myelotoxicity, pancreas toxicity and therapy persistence in adult thiopurine users with or without allopurinol. Methods A retrospective population‐based cohort study was conducted within current thiopurine users (Clinical Practice Research Datalink). Among these patients, co‐use of allopurinol was compared to non‐use. Hazard ratios (HRs) for hepatotoxicity, myelotoxicity and pancreatitis were derived using time‐dependent Cox proportional hazards models, and were adjusted for potential confounders. Persistence of thiopurine use was evaluated using Log‐rank statistics. Results Patients using thiopurines (n = 37 360) were identified of which 1077 were concomitantly taking allopurinol. A 58% decreased risk of hepatotoxicity was observed in those concomitantly taking allopurinol (HR 0.42; 95% CI 0.30–0.60; NNT 46). Rate of myelotoxicity (HR 0.96; 95% CI 0.89–1.03) was not influenced. Risk of pancreatitis was increased (HR 3.00; 95% CI 1.01–8.93; NNH 337), but was only seen in those with active gout (suggesting confounding by indication). Finally, allopurinol co‐users were able to maintain thiopurine therapy over twice as long as those not on allopurinol (3.9 years vs. 1.8 years, P < 0.0001). Conclusion In thiopurine users, allopurinol is associated with a 58% reduced risk of hepatotoxicity. In addition, thiopurine persistence was prolonged by 2.1 years in allopurinol users. These data support the use of allopurinol in individuals requiring thiopurine therapy.
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Affiliation(s)
- Jeroen P A Houwen
- Department of Clinical Pharmacy, University Medical Center Utrecht, Utrecht, Netherlands
| | - Antoine C G Egberts
- Department of Clinical Pharmacy, University Medical Center Utrecht, Utrecht, Netherlands.,Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, Netherlands
| | - Anthonius de Boer
- Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, Netherlands.,Dutch Medicines Evaluation Board (CBG/MEB), Utrecht, Netherlands
| | - Erik M van Maarseveen
- Department of Clinical Pharmacy, University Medical Center Utrecht, Utrecht, Netherlands
| | - Roderick H J Houwen
- Department of Paediatric Gastroenterology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Arief Lalmohamed
- Department of Clinical Pharmacy, University Medical Center Utrecht, Utrecht, Netherlands.,Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, Netherlands
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8
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Roberts RL, Wallace MC, Seinen ML, van Bodegraven AA, Krishnaprasad K, Jones GT, van Rij AM, Baird A, Lawrance IC, Prosser R, Bampton P, Grafton R, Simms LA, Studd C, Bell SJ, Kennedy MA, Halliwell J, Gearry RB, Radford-Smith G, Andrews JM, McHugh PC, Barclay ML. Nonsynonymous Polymorphism in Guanine Monophosphate Synthetase Is a Risk Factor for Unfavorable Thiopurine Metabolite Ratios in Patients With Inflammatory Bowel Disease. Inflamm Bowel Dis 2018; 24:2606-2612. [PMID: 29788244 DOI: 10.1093/ibd/izy163] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Indexed: 12/30/2022]
Abstract
BACKGROUND Up to 20% of patients with inflammatory bowel disease (IBD) who are refractory to thiopurine therapy preferentially produce 6-methylmercaptopurine (6-MMP) at the expense of 6-thioguanine nucleotides (6-TGN), resulting in a high 6-MMP:6-TGN ratio (>20). The objective of this study was to evaluate whether genetic variability in guanine monophosphate synthetase (GMPS) contributes to preferential 6-MMP metabolizer phenotype. METHODS Exome sequencing was performed in a cohort of IBD patients with 6-MMP:6-TGN ratios of >100 to identify nonsynonymous single nucleotide polymorphisms (nsSNPs). In vitro assays were performed to measure GMPS activity associated with these nsSNPs. Frequency of the nsSNPs was measured in a cohort of 530 Caucasian IBD patients. RESULTS Two nsSNPs in GMPS (rs747629729, rs61750370) were detected in 11 patients with very high 6-MMP:6-TGN ratios. The 2 nsSNPs were predicted to be damaging by in silico analysis. In vitro assays demonstrated that both nsSNPs resulted in a significant reduction in GMPS activity (P < 0.05). The SNP rs61750370 was significantly associated with 6-MMP:6-TGN ratios ≥100 (odds ratio, 5.64; 95% confidence interval, 1.01-25.12; P < 0.031) in a subset of 264 Caucasian IBD patients. CONCLUSIONS The GMPS SNP rs61750370 may be a reliable risk factor for extreme 6MMP preferential metabolism.
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Affiliation(s)
- Rebecca L Roberts
- Department of Surgical Sciences (Dunedin), University of Otago, Otago, New Zealand
| | - Mary C Wallace
- Department of Surgical Sciences (Dunedin), University of Otago, Otago, New Zealand
| | - Margien L Seinen
- Department of Gastroenterology and Hepatology, VU University Medical Center, Amsterdam, the Netherlands.,Department of Internal Medicine, Gastroenterology and Geriatrics, Atrium-ORBIS Medical Center, Heerlen-Sittard, the Netherlands
| | - Adriaan A van Bodegraven
- Department of Gastroenterology and Hepatology, VU University Medical Center, Amsterdam, the Netherlands.,Department of Internal Medicine, Gastroenterology and Geriatrics, Atrium-ORBIS Medical Center, Heerlen-Sittard, the Netherlands
| | | | - Gregory T Jones
- Department of Surgical Sciences (Dunedin), University of Otago, Otago, New Zealand
| | - Andre M van Rij
- Department of Surgical Sciences (Dunedin), University of Otago, Otago, New Zealand
| | - Angela Baird
- Centre for Inflammatory Bowel Disease, Saint John of God Hospital, Subiaco, WA, Australia
| | - Ian C Lawrance
- Centre for Inflammatory Bowel Disease, Saint John of God Hospital, Subiaco, WA, Australia.,Harry Perkins Institute of Medical Research, School of Medicine and Pharmacology, University of Western Australia, Murdoch, WA, Australia
| | - Ruth Prosser
- Flinders Medical Centre, Flinders University of South Australia, Bedford Park, South Australia, Australia
| | - Peter Bampton
- Flinders Medical Centre, Flinders University of South Australia, Bedford Park, South Australia, Australia
| | - Rachel Grafton
- Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Lisa A Simms
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Corrie Studd
- Department of Gastroenterology, St Vincent's Hospital, Melbourne, Victoria, Australia
| | - Sally J Bell
- Department of Gastroenterology, St Vincent's Hospital, Melbourne, Victoria, Australia
| | - Martin A Kennedy
- Department of Pathology, University of Otago Christchurch, Christchurch, New Zealand
| | - Jacob Halliwell
- Centre for Biomarker Research, School of Applied Sciences, University of Huddersfield, Huddersfield, UK
| | - Richard B Gearry
- Department of Gastroenterology, Christchurch Hospital, Christchurch, New Zealand
| | - Graham Radford-Smith
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia.,Department of Gastroenterology, Royal Brisbane and Women's Hospital, Brisbane, Queensland, Australia
| | - Jane M Andrews
- Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Patrick C McHugh
- Centre for Biomarker Research, School of Applied Sciences, University of Huddersfield, Huddersfield, UK
| | - Murray L Barclay
- Department of Gastroenterology, Christchurch Hospital, Christchurch, New Zealand
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Lim SZ, Chua EW. Revisiting the Role of Thiopurines in Inflammatory Bowel Disease Through Pharmacogenomics and Use of Novel Methods for Therapeutic Drug Monitoring. Front Pharmacol 2018; 9:1107. [PMID: 30349479 PMCID: PMC6186994 DOI: 10.3389/fphar.2018.01107] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 09/10/2018] [Indexed: 12/12/2022] Open
Abstract
Azathioprine and 6-mercaptopurine, often referred to as thiopurine compounds, are commonly used in the management of inflammatory bowel disease. However, patients receiving these drugs are prone to developing adverse drug reactions or therapeutic resistance. Achieving predefined levels of two major thiopurine metabolites, 6-thioguanine nucleotides and 6-methylmercaptopurine, is a long-standing clinical practice in ensuring therapeutic efficacy; however, their correlation with treatment response is sometimes unclear. Various genetic markers have also been used to aid the identification of patients who are thiopurine-sensitive or refractory. The recent discovery of novel Asian-specific DNA variants, namely those in the NUDT15 gene, and their link to thiopurine toxicity, have led clinicians and scientists to revisit the utility of Caucasian biomarkers for Asian individuals with inflammatory bowel disease. In this review, we explore the limitations associated with the current methods used for therapeutic monitoring of thiopurine metabolites and how the recent discovery of ethnicity-specific genetic markers can complement thiopurine metabolites measurement in formulating a strategy for more accurate prediction of thiopurine response. We also discuss the challenges in thiopurine therapy, alongside the current strategies used in patients with reduced thiopurine response. The review is concluded with suggestions for future work aiming at using a more comprehensive approach to optimize the efficacy of thiopurine compounds in inflammatory bowel disease.
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Affiliation(s)
| | - Eng Wee Chua
- Faculty of Pharmacy, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
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Friedman AB, Brown SJ, Bampton P, Barclay ML, Chung A, Macrae FA, McKenzie J, Reynolds J, Gibson PR, Hanauer SB, Sparrow MP. Randomised clinical trial: efficacy, safety and dosage of adjunctive allopurinol in azathioprine/mercaptopurine nonresponders (AAA Study). Aliment Pharmacol Ther 2018; 47:1092-1102. [PMID: 29468701 DOI: 10.1111/apt.14571] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 09/26/2017] [Accepted: 01/25/2018] [Indexed: 02/06/2023]
Abstract
BACKGROUND Thiopurine hypermethylation towards 6-methylmercaptopurine (6MMP) instead of 6-thioguanine nucleotides (6TGN) is associated with inefficacy in patients with IBD. Allopurinol reverses such hypermethylation. AIMS To prospectively determine efficacy of allopurinol-thiopurine combination and to compare 2 doses of allopurinol. DESIGN In a multicentre, double-blind trial, patients with clinically active or steroid-dependent IBD and thiopurine shunting were randomised to 50 or 100 mg/d allopurinol and 25% of their screening thiopurine dose, which was subsequently optimised, aiming for 6TGN of 260-500 pmol/8x108 RBCs. The primary endpoint was steroid-free clinical remission at 24 weeks. RESULTS Of 73 patients, 39 (53% [95% CI 42-65]) achieved steroid-free remission, (54% with 50 mg/d and 53% with 100 mg/d). 81% were able to discontinue steroids. Therapeutic 6TGN levels were achieved in both groups. Final thiopurine doses were lower with 100 mg/d allopurinol (P < 0.005). 6MMP: 6TGN ratio decreased from mean 64 to 4 (P < 0.001), being higher with 50 mg/d (6 ± 1.83) than for 100 mg/d ([1 ± 0.16], P = 0.003). Three patients on 50 mg/d failed to sustain low ratios at 24 weeks. Toxicity was minimal; three patients on 50 mg/d allopurinol developed transient leukopenia. Alanine aminotransferase concentrations decreased (P < 0.001) similarly in both arms. Faecal calprotectin levels at study end were lower in patients who achieved the primary endpoint (median 171 [85-541] vs 821[110-5892] ug/g, P = 0.03). CONCLUSIONS Low-dose allopurinol-thiopurine combination safely reverses shunting and optimises 6TGN with associated improvement in disease activity. 100 mg/d allopurinol is preferable due to greater metabolite profile stability and lower thiopurine dose without additional toxicity.
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Affiliation(s)
- A B Friedman
- Department of Gastroenterology, The Alfred Hospital and Monash University, Melbourne, Australia
| | - S J Brown
- St Vincent's Hospital, Melbourne, Australia
| | - P Bampton
- Flinders medical Centre, Adelaide, Australia
| | - M L Barclay
- Christchurch Hospital, Christchurch, New Zealand
| | - A Chung
- Eastern Health and Monash University, Melbourne, Australia
| | - F A Macrae
- Royal Melbourne Hospital, Melbourne, Australia
| | - J McKenzie
- The Alfred Hospital and Monash University, Melbourne, Australia
| | - J Reynolds
- The Alfred Hospital and Monash University, Melbourne, Australia
| | - P R Gibson
- The Alfred Hospital and Monash University, Melbourne, Australia
| | | | - M P Sparrow
- The Alfred Hospital and Monash University, Melbourne, Australia
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11
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Munnig-Schmidt E, Zhang M, Mulder CJ, Barclay ML. Late-onset Rise of 6-MMP Metabolites in IBD Patients on Azathioprine or Mercaptopurine. Inflamm Bowel Dis 2018. [PMID: 29522107 DOI: 10.1093/ibd/izx081] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
BACKGROUND The thiopurines azathioprine and mercaptopurine remain pivotal maintenance treatments in inflammatory bowel disease (IBD); however, up to 15%-20% of patients preferentially produce the hepatotoxic metabolite 6-methylmercaptopurine (6MMP) at the expense of the therapeutic 6-thioguanine nucleotides (6TGN). This metabolic shunting usually begins within 3 months of therapy. We noted patients developing shunting many months or years after starting treatment and aimed to determine how often this late shunting occurs and whether this could be explained by patient factors or concomitant medications. METHODS The New Zealand database of thiopurine metabolite results from 2002 to 2016 (19085 6TGN/6MMP pairs from 7130 patients) was interrogated to identify patients developing a 6MMP/6TGN ratio >20 after at least 4 months treatment. Dosing history, concomitant therapy, and comorbidity data were assessed. RESULTS Fifteen percent of database patients developed preferential 6-MMP production, and of these, 29 patients had late-onset shunting with sufficient data available for validation. This extrapolates to 90 patients in total, representing 1.7% of IBD patients on thiopurines, or 10% of all those with preferential 6-MMP production. Time from starting therapy to shunting was 5 months to 10.4 years (median, 21 months). Eleven patients had abnormal liver function when shunting was recognized, all with 6MMP >5900 pmol/8 × 108 red blood cells. No common factors were found to explain the late onset. CONCLUSIONS Some IBD patients develop preferential 6MMP production many months or years after commencing therapy. This is important when considering frequency of metabolite monitoring, failure of therapy, or abnormal liver function. 10.1093/ibd/izx081_video1izx081.video15746667546001.
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Affiliation(s)
- Erik Munnig-Schmidt
- Department of Gastroenterology, VU Medical Centre, Amsterdam, the Netherlands
| | - Mei Zhang
- Department of Medicine, University of Otago Christchurch, Christchurch, New Zealand
| | - Chris J Mulder
- Department of Gastroenterology, VU Medical Centre, Amsterdam, the Netherlands
| | - Murray L Barclay
- Department of Medicine, University of Otago Christchurch, Christchurch, New Zealand.,Departments of Gastroenterology and Clinical Pharmacology, Christchurch Hospital, Christchurch, New Zealand
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12
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Ma J, Sies CW, Pike LS. Analytical and clinical validation of an LC-MS/MS method to measure thiopurine S-methyltransferase activity by quantifying d3-6-MMP. Clin Biochem 2018; 54:100-105. [PMID: 29425801 DOI: 10.1016/j.clinbiochem.2018.02.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2017] [Revised: 01/31/2018] [Accepted: 02/04/2018] [Indexed: 10/18/2022]
Abstract
BACKGROUND Identification of patients with thiopurine S-methyltransferase (TPMT) deficiency prior to thiopurine drug therapy has become routine clinical practice worldwide. To measure TPMT activity, traditional radiochemical assays have been replaced by chromatographic methods. METHOD Inspired by the increasing number of isotope labelled sources that may be of benefit for the TPMT assay, a new LC-MS/MS method for TPMT activity was developed and validated. Isotope labelled d3-S-adenosyl-l-methionine (d3-SAM) was selected for the enzymatic methylation of mercaptopurine during sample incubation; d3-6-methylmercaptopurine (d3-6-MMP) with d2-2, 8-hypoxanthine as the internal standard was quantified to ascertain individual TPMT activity. RESULTS The validation of the analytical part of this method showed good linearity (coefficient of determination 0.9999 in the range of 1-500 ng/mL) with the intra-and inter-day impression CV% between 7.6% and 9.1% and 3.7% and 9.2%, respectively. Recovery ranged from 94.9% to 112.3%. The specificity of the enzymatic reaction was validated by using 108 clinical check samples. After compared with traditional radiochemical assay and genotype results, all homozygous and heterozygous deficiency clinical checks fitted into the nominal groups, inter-batch and intra-batch impression CV% were between 2.3% and 9.7%. CONCLUSION With the inclusion of isotope labelled substrate, interfering non-enzymatic methylation no longer results in potential false assignment of abnormal patients. Furthermore, the method can be applied to patients who have already been prescribed thiopurine drugs. This new LC-MS/MS is therefore a favourable clinical routine application to test TPMT activity, as it shows excellent performance in identifying patients with TPMT deficiency.
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Affiliation(s)
- Jing Ma
- Specialist Chemistry, Canterbury Health Laboratories, Christchurch, New Zealand.
| | - Christiaan W Sies
- Specialist Chemistry, Canterbury Health Laboratories, Christchurch, New Zealand.
| | - Linda S Pike
- Specialist Chemistry, Canterbury Health Laboratories, Christchurch, New Zealand.
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13
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LC-MS/MS Analysis of Erythrocyte Thiopurine Nucleotides and Their Association With Genetic Variants in Patients With Neuromyelitis Optica Spectrum Disorders Taking Azathioprine. Ther Drug Monit 2017; 39:5-12. [PMID: 27941536 DOI: 10.1097/ftd.0000000000000362] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND Azathioprine is a first-line drug in treating neuromyelitis optica spectrum disorders (NMOSD). To exhibit its bioactivity, azathioprine needs to be converted to thiopurine nucleotides (TPNs) including 6-thioguanine nucleotides (6-TGNs) and 6-methylmercaptopurine nucleotides (6-MMPNs) that are affected by genetic polymorphisms. This study aims to develop an LC-MS/MS method for the analysis of erythrocyte concentrations of TPNs and to evaluate their associations with variants of various genes (MTHFR, TPMT, HLA, SLC29A1, SLC28A2, SLC28A3, ABCB1, and ABCC4) in patients with NMOSD. METHODS Erythrocyte 6-TGNs and 6-MMPNs were converted to their free bases 6-thioguanine and 6-methylmercaptopurine derivative by 1-hour acid hydrolysis at 95°C. An LC-MS/MS method was developed, validated, and used to study 32 patients with NMOSD to determine these free bases. Genetic variants were identified by MassARRAY (Sequenom) and multiple SNaPshot techniques. The associations between genetic variants and the concentrations of TPNs or the 6-MMPNs:6-TGNs ratio were evaluated by PLINK software using linear regression. RESULTS Methanol and water were used for separation with a total run time of 6.5 minutes. The lowest limit of quantification was 0.1 μmol/L with an injection volume of 10 μL. rs10868138 (SLC28A3) was associated with a higher erythrocyte concentration of 6-TGNs (P = 0.031), whereas rs12378361 (SLC28A3) was associated with a lower erythrocyte concentration of 6-TGNs (P = 0.0067). rs507964 (SLC29A1) was significantly associated with a lower erythrocyte concentration of 6-MMPNs (P = 0.024) and a lower 6-MMPNs:6-TGNs ratio (P = 0.029). CONCLUSIONS An LC-MS/MS method for the analysis of erythrocyte TPNs was developed, validated, and used to study 32 patients with NMOSD. SLC29A1 and SLC28A3 were associated with the erythrocyte concentrations of TPNs and 6-MMPNs:6-TGNs ratio. Further studies are needed to confirm these results.
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14
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Garritsen FM, van der Schaft J, Bruijnzeel-Koomen CAF, van Schaik RH, de Graaf M, van den Broek MPH, de Bruin-Weller MS. Thiopurine metabolite levels in patients with atopic dermatitis and/or chronic hand/foot eczema treated with azathioprine. J DERMATOL TREAT 2017; 29:375-382. [PMID: 28914560 DOI: 10.1080/09546634.2017.1373738] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND Azathioprine is frequently used in severe eczema. It is converted in the liver into active metabolites, including 6-thioguanine nucleotide (6-TGN) and methylated 6-methylmercaptopurine (6-MMP). In the past, the therapeutic potential of azathioprine may have not been fully utilized. Recent investigations on inflammatory bowel disease have led to a better understanding of azathioprine metabolism and optimizing treatment. OBJECTIVE To investigate whether measuring thiopurine metabolites in circulation can improve the effectiveness and safety of azathioprine treatment in patients with atopic dermatitis and/or chronic hand/foot eczema. METHODS Azathioprine metabolite levels were measured in eczema patients during maintenance treatment (Part I) and dose escalation (Part II). Clinical effectiveness, hepatotoxicity, and bone marrow suppression were analyzed and TPMT genotype was assessed. RESULTS A wide variation in metabolite levels in all dose groups was observed. In Part I (32 patients), there were no significant differences in 6-TGN levels between clinical responders and non-responders (p = .806). No hepatoxicity or myelotoxicity was observed. In Part II, all 6-TGN and 6-MMP levels increased during dose escalation. Hypermethylation was observed in 2/8 patients. CONCLUSION For individual eczema patients treated with azathioprine, routinely measuring 6-TGN and 6-MMP can be helpful in optimizing azathioprine dose, improving clinical effectiveness, and preventing side effects.
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Affiliation(s)
- F M Garritsen
- a Department of Dermatology , University Medical Center Utrecht , Utrecht , The Netherlands
| | - J van der Schaft
- a Department of Dermatology , University Medical Center Utrecht , Utrecht , The Netherlands
| | | | - R H van Schaik
- b Department of Clinical Chemistry , Erasmus University Medical Center Rotterdam , Rotterdam , The Netherlands.,c Laboratory for Clinical Chemistry and Hematology (LKCH) , University Medical Center Utrecht , Utrecht , The Netherlands
| | - M de Graaf
- a Department of Dermatology , University Medical Center Utrecht , Utrecht , The Netherlands
| | - M P H van den Broek
- d Department of Clinical Pharmacy , University Medical Center Utrecht , Utrecht , The Netherlands.,e Department of Clinical Pharmacy , St Antonius Hospital , Nieuwegein , The Netherlands
| | - M S de Bruin-Weller
- a Department of Dermatology , University Medical Center Utrecht , Utrecht , The Netherlands
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15
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Meijer B, Kreijne JE, van Moorsel SAW, Derijks LJJ, Bouma G, Mulder CJJ, Wong DR, van der Woude CJ, van Bodegraven AA, de Boer NKH. 6-methylmercaptopurine-induced leukocytopenia during thiopurine therapy in inflammatory bowel disease patients. J Gastroenterol Hepatol 2017; 32:1183-1190. [PMID: 27859568 DOI: 10.1111/jgh.13656] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 11/07/2016] [Accepted: 11/11/2016] [Indexed: 01/15/2023]
Abstract
BACKGROUND AND AIM Thiopurines have a favorable benefit-risk ratio in the treatment of inflammatory bowel disease. A feared adverse event of thiopurine therapy is myelotoxicity, mostly occurring due to toxic concentrations of the pharmacologically active metabolites 6-thioguaninenucleotides. In oncology, myelosuppression has also been associated with elevated 6-methylmercaptopurine (6-MMP). In this case series, we provide a detailed overview of 6-MMP-induced myelotoxicity in inflammatory bowel disease patients. METHODS We retrospectively scrutinized pharmacological laboratory databases of five participating centers over a 5-year period. Patients with leukocytopenia at time of elevated 6-MMP levels (>5700 pmol/8 × 108 red blood cells) were included for detailed chart review. RESULTS In this case series, we describe demographic, clinical, and pharmacological aspects of 24 cases of 6-MMP-induced myelotoxicity on weight-based thiopurine therapy with a median steady-state 6-MMP level of 14 500 pmol/8 × 108 red blood cells (range 6600-48 000). All patients developed leukocytopenia (white blood cell count 2.7 ± 0.9 × 109 /L) after a median period of 11 weeks after initiation of thiopurine therapy (interquartile range 6-46 weeks). Eighteen patients (75%) developed concurrent anemia (median hemoglobin concentration 6.9 × 109 /L), and four patients developed concurrent thrombocytopenia (median platelet count 104 × 109 /L). Leukocytopenia resolved in 20 patients (83%) within 4 weeks upon altered thiopurine treatment regimen, and white blood cell count was increasing, but not yet normalized, in the remaining four patients. CONCLUSION We observed that thiopurine-induced myelotoxicity also occurs because of (extremely) high 6-MMP concentrations in patients with a skewed thiopurine metabolism. Continued treatment with adapted thiopurine therapy was successful in almost all patients.
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Affiliation(s)
- Berrie Meijer
- Department of Gastroenterology and Hepatology, VU University Medical Center, Amsterdam, The Netherlands
| | - Joany E Kreijne
- Department of Gastroenterology and Hepatology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Sofia A W van Moorsel
- Department of Clinical Pharmacy, Pharmacology and Toxicology, Zuyderland Medical Center, Heerlen-Sittard-Geleen, The Netherlands.,Department of Clinical Pharmacy, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Luc J J Derijks
- Department of Clinical Pharmacy, Máxima Medical Center, Veldhoven, The Netherlands
| | - Gerd Bouma
- Department of Gastroenterology and Hepatology, VU University Medical Center, Amsterdam, The Netherlands
| | - Chris J J Mulder
- Department of Gastroenterology and Hepatology, VU University Medical Center, Amsterdam, The Netherlands
| | - Dennis R Wong
- Department of Clinical Pharmacy, Pharmacology and Toxicology, Zuyderland Medical Center, Heerlen-Sittard-Geleen, The Netherlands
| | - C Janneke van der Woude
- Department of Gastroenterology and Hepatology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Adriaan A van Bodegraven
- Department of Gastroenterology and Hepatology, VU University Medical Center, Amsterdam, The Netherlands.,Department of Gastroenterology, Geriatrics, Internal and Intensive Care Medicine (Co-MIK), Zuyderland Medical Center, Heerlen-Sittard-Geleen, The Netherlands
| | - Nanne K H de Boer
- Department of Gastroenterology and Hepatology, VU University Medical Center, Amsterdam, The Netherlands
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16
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Pharmacogénétique des immunosuppresseurs : état des connaissances et des pratiques – recommandations du Réseau national de pharmacogénétique (RNPGx). Therapie 2017; 72:269-284. [DOI: 10.1016/j.therap.2016.09.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 09/02/2016] [Indexed: 12/18/2022]
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17
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Combination treatment with 6-mercaptopurine and allopurinol in HepG2 and HEK293 cells - Effects on gene expression levels and thiopurine metabolism. PLoS One 2017; 12:e0173825. [PMID: 28278299 PMCID: PMC5344510 DOI: 10.1371/journal.pone.0173825] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 02/26/2017] [Indexed: 12/13/2022] Open
Abstract
Combination treatment with low-dose thiopurine and allopurinol (AP) has successfully been used in patients with inflammatory bowel disease with a so called skewed thiopurine metabolite profile. In red blood cells in vivo, it reduces the concentration of methylated metabolites and increases the concentration of the phosphorylated ones, which is associated with improved therapeutic efficacy. This study aimed to investigate the largely unknown mechanism of AP on thiopurine metabolism in cells with an active thiopurine metabolic pathway using HepG2 and HEK293 cells. Cells were treated with 6-mercaptopurine (6MP) and AP or its metabolite oxypurinol. The expression of genes known to be associated with thiopurine metabolism, and the concentration of thiopurine metabolites were analyzed. Gene expression levels were only affected by AP in the presence of 6MP. The addition of AP to 6MP affected the expression of in total 19 genes in the two cell lines. In both cell lines the expression of the transporter SLC29A2 was reduced by the combined treatment. Six regulated genes in HepG2 cells and 8 regulated genes in HEK293 cells were connected to networks with 18 and 35 genes, respectively, present at known susceptibility loci for inflammatory bowel disease, when analyzed using a protein-protein interaction database. The genes identified as regulated as well as the disease associated interacting genes represent new candidates for further investigation in the context of combination therapy with thiopurines and AP. However, no differences in absolute metabolite concentrations were observed between 6MP+AP or 6MP+oxypurinol vs. 6MP alone in either of the two cell lines. In conclusion; the effect of AP on gene expression levels requires the presence of 6MP, at least in vitro. Previously described AP-effects on metabolite concentrations observed in red blood cells in vivo could not be reproduced in our cell lines in vitro. AP’s effects in relation to thiopurine metabolism are complex. The network-identified susceptibility genes represented biological processes mainly associated with purine nucleotide biosynthetic processes, lymphocyte proliferation, NF-KB activation, JAK-STAT signaling, and apoptotic signaling at oxidative stress.
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18
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Wong DR, Coenen MJH, Vermeulen SH, Derijks LJJ, van Marrewijk CJ, Klungel OH, Scheffer H, Franke B, Guchelaar HJ, de Jong DJ, Engels LGJB, Verbeek ALM, Hooymans PM. Early Assessment of Thiopurine Metabolites Identifies Patients at Risk of Thiopurine-induced Leukopenia in Inflammatory Bowel Disease. J Crohns Colitis 2017; 11:175-184. [PMID: 27402913 DOI: 10.1093/ecco-jcc/jjw130] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 06/10/2016] [Accepted: 06/21/2016] [Indexed: 01/28/2023]
Abstract
BACKGROUND AND AIMS Only a quarter of thiopurine-induced myelotoxicity in inflammatory bowel disease [IBD] patients is related to thiopurine S-methyltransferase deficiency. We determined the predictive value of 6-thioguanine nucleotide [6-TGN] and 6-methylmercaptopurine ribonucleotide [6-MMPR] concentrations 1 week after initiation [T1] for development of leukopenia during the first 8 weeks of thiopurine treatment. METHODS The study was performed in IBD patients starting thiopurine therapy as part of the Dutch randomized controlled TOPIC trial [ClinicalTrials.gov NCT00521950]. Blood samples for metabolite measurement were collected at T1. Leukopenia was defined by leukocyte counts of <3.0 × 109/L. For comparison, patients without leukopenia who completed the 8 weeks on the stable dose were selected from the first 272 patients of the TOPIC trial. RESULTS Thirty-two patients with, and 162 patients without leukopenia were analysed. T1 threshold 6-TGN concentrations of 213 pmol/8 × 108 erythrocytes and 3525 pmol/8 × 108 erythrocytes for 6-MMPR were defined: patients exceeding these values were at increased leukopenia risk (odds ratio [OR] 6.2 [95% CI: 2.8-13.8] and 5.9 [95% CI: 2.7-13.3], respectively). Leukopenia rates were higher in patients treated with mercaptopurine, compared with azathioprine (OR 7.3 [95% CI: 3.1-17.0]), and concurrent anti-TNF therapy (OR 5.1 [95% CI: 1.6-16.4]). Logistic regression analysis of thiopurine type, threshold concentrations, and concurrent anti-tumour necrosis factor [TNF] therapy revealed that elevations of both T1 6-TGN and 6-MMPR resulted in the highest risk for leukopenia, followed by exceeding only the T1 6-MMPR or 6-TGN threshold concentration (area under the curve 0.84 [95% CI: 0.76-0.92]). CONCLUSIONS In ~80% of patients, leukopenia could be explained by T1 6-TGN and/or 6-MMPR elevations. Validation of the predictive model is needed before implementing in clinical practice.
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Affiliation(s)
- Dennis R Wong
- Department of Clinical Pharmacy, Pharmacology and Toxicology, Zuyderland Medical Center, Sittard-Geleen, The Netherlands
| | - Marieke J H Coenen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Sita H Vermeulen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Department for Health Evidence, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Luc J J Derijks
- Department of Clinical Pharmacy, Máxima Medical Centre, Veldhoven, The Netherlands
| | - Corine J van Marrewijk
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Olaf H Klungel
- Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute of Pharmaceutical Sciences, Utrecht University, The Netherlands
| | - Hans Scheffer
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Barbara Franke
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Psychiatry, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Henk-Jan Guchelaar
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Dirk J de Jong
- Department of Gastroenterology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Leopold G J B Engels
- Department of Gastroenterology, Zuyderland Medical Center, Sittard-Geleen, The Netherlands
| | - André L M Verbeek
- Department for Health Evidence, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Piet M Hooymans
- Department of Clinical Pharmacy, Pharmacology and Toxicology, Zuyderland Medical Center, Sittard-Geleen, The Netherlands
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Woillard JB, Chouchana L, Picard N, Loriot MA. Pharmacogenetics of immunosuppressants: State of the art and clinical implementation - recommendations from the French National Network of Pharmacogenetics (RNPGx). Therapie 2017; 72:285-299. [PMID: 28318610 DOI: 10.1016/j.therap.2016.09.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 09/02/2016] [Indexed: 12/21/2022]
Abstract
Therapeutic drug monitoring is already widely used for immunosuppressive drugs due to their narrow therapeutic index. This article summarizes evidence reported in the literature regarding the pharmacogenetics of (i) immunosuppressive drugs used in transplantation and (ii) azathioprine used in chronic inflammatory bowel disease. The conditions of use of currently available major pharmacogenetic tests are detailed and recommendations are provided based on a scale established by the RNPGx scoring tests as "essential", "advisable" and "potentially useful". Other applications for which the level of evidence is still debated are also discussed.
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Affiliation(s)
- Jean-Baptiste Woillard
- Service de pharmacologie, toxicologie et pharmacovigilance, centre de biologie et de recherche en santé, CHU de Limoges, 87042 Limoges, France; Université de Limoges UMR_S850, 87000 Limoges, France.
| | - Laurent Chouchana
- Service de pharmacologie, hôpital Cochin, Assistance publique-Hôpitaux de Paris (AP-HP), 75014 Paris, France
| | - Nicolas Picard
- Service de pharmacologie, toxicologie et pharmacovigilance, centre de biologie et de recherche en santé, CHU de Limoges, 87042 Limoges, France; Université de Limoges UMR_S850, 87000 Limoges, France
| | - Marie-Anne Loriot
- Inserm UMR_S1147, centre universitaire des Saints-Pères, 75006 Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France; Service de biochimie, hôpital européen Georges-Pompidou, Assistance publique-Hôpitaux de Paris (AP-HP), 75015 Paris, France
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20
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Chapdelaine A, Mansour AM, Troyanov Y, Williamson DR, Doré M. Metabolite monitoring to guide thiopurine therapy in systemic autoimmune diseases. Clin Rheumatol 2017; 36:1341-1348. [PMID: 28130685 DOI: 10.1007/s10067-017-3554-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 12/22/2016] [Accepted: 01/18/2017] [Indexed: 02/06/2023]
Abstract
6-Thioguanine nucleotide (6-TGN) is the active metabolite of thiopurine drugs azathioprine and 6-mercaptopurine. 6-Methylmercaptopurine (6-MMP) is an inactive and potentially hepatotoxic metabolite. A subgroup of patients (shunters) preferentially produce 6-MMP instead of 6-TGN, therefore displaying thiopurine resistance and risk for hepatotoxicity. Outside inflammatory bowel disease literature, few data exist regarding individualized thiopurine therapy based on metabolite monitoring. This study sought to describe metabolite monitoring in patients receiving weight-based thiopurine for systemic autoimmune diseases. Patients were enrolled using a laboratory database, and data were retrospectively collected. The correlation between the highest thiopurine dose (mg/kg) and the 6-TGN concentration (pmol/8 × 108 erythrocytes) was estimated with Pearson's correlation coefficient. Seventy-one patients with various systemic autoimmune conditions were enrolled. The correlation between the thiopurine dose and the 6-TGN level was weak for the overall patient sample (r = 0.201, p = 0.092) and for the subgroup of non-shunters (r = 0.278, p = 0.053). Subjects with 6-MMP levels >5700 pmol/8 × 108 erythrocytes had more hepatic cytolysis compared to subjects with 6-MMP <5700, OR = 4.36 (CI 95% 1.18-16.13, p = 0.027). Twenty-two patients (31%) were identified as shunters. Six shunters developed hepatotoxicity, five of which had 6-MMP concentration >5700. Eleven non-shunters had hepatotoxicity, one of which had 6-MMP >5700. Thiopurine metabolite monitoring shows wide variability in 6-TGN levels among patients treated with weight-based thiopurine for systemic autoimmune diseases. Thirty-one percent of the patients in our series fulfilled the shunter definition. Thiopurine metabolite monitoring and dose adjustment to improve maintenance of remission and avoid hepatotoxicity should be studied prospectively.
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Affiliation(s)
- Aurélie Chapdelaine
- Department of Medicine, Hôpital du Sacré-Cœur de Montréal, 5400 Gouin Ouest, Montréal, Québec, H4J 1C5, Canada.
| | - Anne-Marie Mansour
- Department of Medicine, Hôpital du Sacré-Cœur de Montréal, 5400 Gouin Ouest, Montréal, Québec, H4J 1C5, Canada
- Faculty of Medicine, Université de Montréal, 5400 Gouin Ouest, Montréal, Québec, H4J 1C5, Canada
| | - Yves Troyanov
- Department of Medicine, Hôpital du Sacré-Cœur de Montréal, 5400 Gouin Ouest, Montréal, Québec, H4J 1C5, Canada
| | - David R Williamson
- Department of Pharmacy, Hôpital du Sacré-Cœur de Montréal, 5400 Gouin Ouest, Montréal, Québec, H4J 1C5, Canada
- Faculty of Pharmacy, Université de Montréal, 5400 Gouin Ouest, Montréal, Québec, H4J 1C5, Canada
| | - Maxime Doré
- Department of Pharmacy, Hôpital du Sacré-Cœur de Montréal, 5400 Gouin Ouest, Montréal, Québec, H4J 1C5, Canada
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21
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Coskun M, Steenholdt C, de Boer NK, Nielsen OH. Pharmacology and Optimization of Thiopurines and Methotrexate in Inflammatory Bowel Disease. Clin Pharmacokinet 2016; 55:257-74. [PMID: 26255287 DOI: 10.1007/s40262-015-0316-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Improving the efficacy and reducing the toxicity of thiopurines and methotrexate (MTX) have been areas of intense basic and clinical research. An increased knowledge on pharmacodynamics and pharmacokinetics of these immunomodulators has optimized treatment strategies in inflammatory bowel disease (IBD). This review focuses on the metabolism and mode of action of thiopurines and MTX, and provides an updated overview of individualized treatment strategies in which efficacy in IBD can be increased without compromising safety. The patient-based monitoring instruments adapted into clinical practice include pretreatment thiopurine S-methyltransferase testing, thiopurine metabolite monitoring, and blood count measurements that may help guiding the dosage to improve clinical outcome. Other approaches for optimizing thiopurine therapy in IBD include combination therapy with allopurinol, 5-aminosalicylates, and/or biologics. Similar strategies are yet to be proven effective in improving the outcome of MTX therapy. Important challenges for the management of IBD in the future relate to individualized dosing of immunomodulators for maximal efficacy with minimal risk of side effects. As low-cost conventional immunomodulators still remain a mainstay in pharmacotherapy of IBD, more research remains warranted, especially to substantiate these tailored management strategies in controlled clinical trials.
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Affiliation(s)
- Mehmet Coskun
- Department of Gastroenterology, Herlev Hospital, University of Copenhagen, Herlev, Denmark. .,Department of Biology and Biotech Research and Innovation Centre (BRIC), The Bioinformatics Centre, University of Copenhagen, Copenhagen, Denmark.
| | - Casper Steenholdt
- Department of Gastroenterology, Herlev Hospital, University of Copenhagen, Herlev, Denmark
| | - Nanne K de Boer
- Department of Gastroenterology and Hepatology, VU University Medical Center, Amsterdam, The Netherlands
| | - Ole Haagen Nielsen
- Department of Gastroenterology, Herlev Hospital, University of Copenhagen, Herlev, Denmark
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González-Lama Y, Gisbert JP. Monitoring thiopurine metabolites in inflammatory bowel disease. Frontline Gastroenterol 2016; 7:301-307. [PMID: 28839871 PMCID: PMC5369498 DOI: 10.1136/flgastro-2015-100681] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 03/09/2016] [Accepted: 03/16/2016] [Indexed: 02/04/2023] Open
Abstract
Thiopurines (azathioprine and mercaptopurine) are one of the immunosuppressive mainstays for the treatment of inflammatory bowel disease. In spite of its widespread use, thiopurine metabolism is still not fully understood, and a significant proportion of patients suffer toxicity or lack of efficacy. Different enzymatic pathways with individual variations constitute a pharmacogenetic model that seems to be suitable for monitoring and therapeutic intervention. This review is focused on current concepts and recent research that may help clinicians to rationally optimise thiopurine treatment in patients with inflammatory bowel disease.
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Affiliation(s)
- Yago González-Lama
- Gastroenterology and Hepatology Department, Puerta de Hierro University Hospital, Majadahonda, Madrid, Spain
| | - Javier P Gisbert
- Gastroenterology Unit, Hospital Universitario de La Princesa and Instituto de Investigación Sanitaria Princesa (IIS-IP), Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Madrid, Madrid, Spain
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Routinely Established Skewed Thiopurine Metabolism Leads to a Strikingly High Rate of Early Therapeutic Failure in Patients With Inflammatory Bowel Disease. Ther Drug Monit 2016; 37:797-804. [PMID: 25853923 DOI: 10.1097/ftd.0000000000000213] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
BACKGROUND The conventional thiopurines azathioprine and mercaptopurine are considered maintenance immunosuppressive drugs of choice in the treatment of inflammatory bowel disease (IBD). Unfortunately, treatment is often discontinued because of adverse events (AEs) or refractoriness, retrospectively associated with the high levels of the thiopurine metabolites 6-methylmercaptopurine ribonucleotides (6-MMPR). Patients with a clinically "skewed" thiopurine metabolism may be particularly at risk for therapy failure. We determined the predictive value of this pharmacological phenomenon in patients with IBD during regular thiopurine therapy. METHODS Clinical effectiveness and tolerability of weight-based thiopurine therapy were determined in all patients with IBD displaying a skewed metabolism [ratio 6-MMPR/6-thioguanine nucleotide (6-TGN) >20]. All samples were routinely assessed between 2008 and 2012, as part of standard clinical follow-up after initiation of conventional thiopurine therapy. RESULTS Forty-one (84%) of 49 included patients with IBD discontinued thiopurines (55% female, 53% with Crohn disease) with a median duration of 14 weeks (range, 7-155). The majority of patients with a skewed metabolism discontinued thiopurines because of adverse events (55%) or refractoriness (12%). The most commonly observed adverse event was hepatotoxicity (18 patients, 37%). Median 6-TGN level was 159 pmol/8 × 10 RBC (range, 46-419), median 6-MMPR level was 11,020 pmol/8 × 10 RBC (range, 3610-43,670), and the median 6-MMPR/6-TGN ratio was 72 (range, 29-367). Thiopurine therapy failure was associated with a ratio above 50 (P < 0.03). Hepatotoxicity occurred more frequently in patients with an extremely skewed metabolism (6-MMPR/6-TGN ratio >100) (P < 0.01). CONCLUSIONS This study demonstrates that a routinely established skewed metabolism is a major risk factor for future thiopurine failure in patients with IBD. These observations imply that routine thiopurine metabolite measurements may be used as a prognostic tool to identify those patients with an aberrant-skewed metabolism at an early stage, possibly benefitting from therapy adjustments.
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Long-term Safety and Efficacy of Low-dose Azathioprine and Allopurinol Cotherapy in Inflammatory Bowel Disease: A Large Observational Study. Inflamm Bowel Dis 2016; 22:1639-46. [PMID: 27271488 DOI: 10.1097/mib.0000000000000827] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND Low-dose azathioprine with allopurinol (LDAA) has been proposed as a potent therapy in inflammatory bowel disease (IBD) with the benefit of overcoming side effects regularly associated with thiopurine monotherapy and poor responses. Concerns regarding safety remain, while a layer of complexity has been added by the trend toward treatment directed by red cell thioguanine nucleotide (TGN) profiling. We report on the clinical efficacy and safety of LDAA use in IBD undirected by metabolite profiling. METHODS Observational study of clinical practice from a single IBD center. Patient outcomes were defined clinically based on established activity scores and corticosteroid withdrawal. Red cell TGN was monitored only for suspected nonadherence. RESULTS Overall, 113/164 (69%) patients with Crohn's disease and 83/136 (61%) patients with ulcerative/unclassified colitis had a clinical response by the end of follow-up (median 19 months), while 85 (52%) patients with Crohn's disease and 74 (54%) patients with ulcerative/unclassified colitis were in clinical remission. Clinical response was seen in 45/57 (79%) patients with Crohn's disease and 34/53 (64%) patients with ulcerative/unclassified colitis who were thiopurine naive, had active IBD, and received LDAA as the first line immunomodulator, while in 35 (61%) and 28 (53%), respectively, remission was achieved. LDAA was stopped in 20/300 (7%) patients because of side effects, all of which resolved on drug cessation. CONCLUSIONS This is the largest cohort supporting the favorable safety profile and high efficacy of LDAA in IBD. It presents 2 advances in therapy: prescribing LDAA for thiopurine-naive patients, and bypassing TGN monitoring in favor of clinical monitoring (blood counts, etc.), which will make it more accessible for clinics without access to TGN assays.
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Allopurinol Use During Maintenance Therapy for Acute Lymphoblastic Leukemia Avoids Mercaptopurine-related Hepatotoxicity. J Pediatr Hematol Oncol 2016; 38:147-51. [PMID: 26808368 DOI: 10.1097/mph.0000000000000499] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
6-Mercaptopurine (6-MP) is the mainstay of treatment for acute lymphoblastic leukemia and lymphoblastic lymphoma. It is metabolized into the pharmacologically active, 6-thioguanine nucleotide (6-TGN), and 6-methyl mercaptopurine nucleotides (6-MMPN), which is associated with hepatotoxicity that jeopardizes antileukemic therapy. Allopurinol alters the metabolism of 6-MP to increase 6-TGN levels and decreases 6-methyl mercaptopurine nucleotides levels. We report 2 cases in which combination therapy of allopurinol with 6-MP was used successfully to avoid hepatotoxicity while delivering adequate 6-TGN levels. We suggest that this combination therapy can be used safely to change the metabolite production in patients who develop excessive hepatotoxicity.
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Karas-Kuželički N, Šmid A, Tamm R, Metspalu A, Mlinarič-Raščan I. From pharmacogenetics to pharmacometabolomics: SAM modulates TPMT activity. Pharmacogenomics 2015; 15:1437-49. [PMID: 25303295 DOI: 10.2217/pgs.14.84] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
AIM In the present study, the influence of SAM on TPMT activity in vivo on human subjects was investigated. SUBJECTS & METHODS A total of 1017 donors from the Estonian Genome Center of the University of Tartu (Estonia) were genotyped for common TPMT variants, evaluated for TPMT activity, SAM levels, a set of 19 biochemical and ten hematological parameters and demographic data. RESULTS After adjustment in multiple regression models and correction for multiple testing, from the 43 factors that were tested, only TPMT genotype (p = 1 × 10(-13)) and SAM levels (p = 1 × 10(-13)) were found to significantly influence TPMT activity. The influence of SAM on TPMT activity was more pronounced in TPMT-heterozygous than wild-type individuals. CONCLUSION SAM represents a potential pharmacometabolomic marker and therapeutic agent in TPMT-heterozygous subjects.
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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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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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Chouchana L, Fernández-Ramos AA, Dumont F, Marchetti C, Ceballos-Picot I, Beaune P, Gurwitz D, Loriot MA. Molecular insight into thiopurine resistance: transcriptomic signature in lymphoblastoid cell lines. Genome Med 2015; 7:37. [PMID: 26015807 PMCID: PMC4443628 DOI: 10.1186/s13073-015-0150-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 03/03/2015] [Indexed: 12/15/2022] Open
Abstract
Background There has been considerable progress in the management of acute lymphoblastic leukemia (ALL) but further improvement is needed to increase long-term survival. The thiopurine agent 6-mercaptopurine (6-MP) used for ALL maintenance therapy has a key influence on clinical outcomes and relapse prevention. Genetic inheritance in thiopurine metabolism plays a major role in interindividual clinical response variability to thiopurines; however, most cases of thiopurine resistance remain unexplained. Methods We used lymphoblastoid cell lines (LCLs) from healthy donors, selected for their extreme thiopurine susceptibility. Thiopurine metabolism was characterized by the determination of TPMT and HPRT activity. We performed genome-wide expression profiling in resistant and sensitive cell lines with the goal of elucidating the mechanisms of thiopurine resistance. Results We determined a higher TPMT activity (+44%; P = 0.024) in resistant compared to sensitive cell lines, although there was no difference in HPRT activity. We identified a 32-gene transcriptomic signature that predicts thiopurine resistance. This signature includes the GTPBP4 gene coding for a GTP-binding protein that interacts with p53. A comprehensive pathway analysis of the genes differentially expressed between resistant and sensitive cell lines indicated a role for cell cycle and DNA mismatch repair system in thiopurine resistance. It also revealed overexpression of the ATM/p53/p21 pathway, which is activated in response to DNA damage and induces cell cycle arrest in thiopurine resistant LCLs. Furthermore, overexpression of the p53 target gene TNFRSF10D or the negative cell cycle regulator CCNG2 induces cell cycle arrest and may also contribute to thiopurine resistance. ARHGDIA under-expression in resistant cell lines may constitute a novel molecular mechanism contributing to thiopurine resistance based on Rac1 inhibition induced apoptosis and in relation with thiopurine pharmacodynamics. Conclusion Our study provides new insights into the molecular mechanisms underlying thiopurine resistance and suggests a potential research focus for developing tailored medicine. Electronic supplementary material The online version of this article (doi:10.1186/s13073-015-0150-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Laurent Chouchana
- INSERM UMR-S 1147, 45 rue des Saints-Pères, Paris, 75006 France ; Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints-Pères, Paris, 75006 France
| | - Ana Aurora Fernández-Ramos
- INSERM UMR-S 1147, 45 rue des Saints-Pères, Paris, 75006 France ; Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints-Pères, Paris, 75006 France
| | - Florent Dumont
- Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints-Pères, Paris, 75006 France ; INSERM U1016, Institut Cochin, 22 Rue Mechain, Paris, 75014 France
| | - Catherine Marchetti
- INSERM UMR-S 1147, 45 rue des Saints-Pères, Paris, 75006 France ; Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints-Pères, Paris, 75006 France
| | - Irène Ceballos-Picot
- Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints-Pères, Paris, 75006 France ; Assistance Publique-Hôpitaux de Paris, Hôpital Necker-Enfants Malades, Biochimie Métabolique, 149 Rue de Sèvres, Paris, 75015 France
| | - Philippe Beaune
- INSERM UMR-S 1147, 45 rue des Saints-Pères, Paris, 75006 France ; Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints-Pères, Paris, 75006 France ; Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Biochimie Pharmacogénétique et Oncologie Moléculaire, 20 rue Leblanc, Paris, 75015 France
| | - David Gurwitz
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Marie-Anne Loriot
- INSERM UMR-S 1147, 45 rue des Saints-Pères, Paris, 75006 France ; Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints-Pères, Paris, 75006 France ; Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Biochimie Pharmacogénétique et Oncologie Moléculaire, 20 rue Leblanc, Paris, 75015 France
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Exome sequencing and array-based comparative genomic hybridisation analysis of preferential 6-methylmercaptopurine producers. THE PHARMACOGENOMICS JOURNAL 2015; 15:414-21. [DOI: 10.1038/tpj.2015.9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 01/15/2014] [Accepted: 01/28/2015] [Indexed: 12/23/2022]
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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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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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Hullah EA, Blaker PA, Marinaki AM, Escudier MP, Sanderson JD. A practical guide to the use of thiopurines in oral medicine. J Oral Pathol Med 2014; 44:761-8. [PMID: 25529219 DOI: 10.1111/jop.12274] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/08/2014] [Indexed: 12/11/2022]
Abstract
Thiopurines are widely used as first-line immunosuppressive therapies in the management of chronic inflammatory oral disease. However, despite over half a century of clinical experience, the evidence base for their use is limited. The aims of this paper were to review the evidence for the use of thiopurines in oral medicine and provide a contemporary model of thiopurine metabolism and mechanism of action and a rationale for clinical use and safe practice.
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Affiliation(s)
- E A Hullah
- Oral Medicine, King's College London Dental Institute, London, UK
| | - P A Blaker
- Gastroenterology, Guy's & St Thomas' Hospitals NHS Foundation Trust, Guy's Hospital, Great Maze Pond, London, UK
| | - A M Marinaki
- Purine Research Laboratory, Viapath, Guy's & St Thomas' Hospitals NHS Foundation Trust, Guy's Hospital, Great Maze Pond, London, UK
| | - M P Escudier
- Oral Medicine, King's College London Dental Institute, London, UK
| | - J D Sanderson
- Gastroenterology, Guy's & St Thomas' Hospitals NHS Foundation Trust, Guy's Hospital, Great Maze Pond, London, UK
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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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Friedman AB, Sparrow MP, Gibson PR. The role of thiopurine metabolites in inflammatory bowel disease and rheumatological disorders. Int J Rheum Dis 2014; 17:132-41. [PMID: 24618304 DOI: 10.1111/1756-185x.12204] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Thiopurines have been a cornerstone of medical management of patients with inflammatory bowel disease(IBD) and many rheumatological disorders. The thiopurines are metabolized to their end products, 6-methymercaptopurine (6MMP) and the 6-thioguanine nucleotides (6TGN), with 6TGN being responsible for thiopurine efficacy by causing apoptosis and preventing activation and proliferation of T-lymphocytes. In IBD, conventional weight-based dosing with thiopurines leads to an inadequate response in many patients. Utilizing measurement of these metabolites and then employing dose optimization strategies has led to markedly improved outcomes in IBD. Switching between thiopurines as well as the addition of low-dose allopurinol can overcome adverse events and elevate 6TGN levels into the therapeutic window. There is a paucity of data on thiopurine metabolites in rheumatological diseases and further research is required.
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Abstract
OBJECTIVES Thiopurines (azathioprine, 6-mercaptopurine) are a mainstay of treatment in Crohn disease (CD). Monitoring intracellular metabolite (6-thioguanine nucleotides [6-TGN] and 6-methylmercaptopurine [6-MMP]) levels can help optimize therapeutic efficacy and minimize potential toxicity. Determination of 6-MMP/6-TGN ratios may provide additional useful information, such as the identification of individuals with excessive thiopurine methyltransferase activity and disadvantageous 6-MMP overproduction. These patients are at increased risk of therapeutic failure and hepatotoxicity. The aim of the study was to evaluate the correlation of 6-MMP/6-TGN ratios with therapeutic efficacy and risk of hepatotoxicity in CD. METHODS The present study was a single-center cross-sectional study including pediatric patients with CD studied prospectively with clinical and laboratory assessments along with serial measurements of 6-MMP and 6-TGN. Clinical response was determined using established clinical indices. RESULTS The study included 238 pediatric patients with CD with a total of 1648 evaluation points. The patients were in steroid-free remission at 59.1% of the evaluation points. 6-MMP/6-TGN ratios of 4 to 24 were protective against relapse (odds ratio [OR] 0.52, 95% confidence interval [CI] -0.39 to 0.69, P = 0.001). Hepatotoxicity was associated with high 6-MMP levels (>3919 pmol/8 × 10 red blood cell count: OR 7.65, 95% CI 3.7-15.9, P = 0.001) and high 6-MMP/6-TGN ratios (>24: OR 5.35, 95% CI -3.43 to 8.43, P = 0.001). CONCLUSIONS We observed significant associations between 6-MMP/6-TGN ratios and clinical response, and risk of hepatotoxicity. Our results suggest that determination of thiopurine metabolite ratios is a valuable tool for identification of patients at increased risk of therapeutic failure and hepatotoxicity.
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Kasirer Y, Mevorach R, Renbaum P, Algur N, Soiferman D, Beeri R, Rachman Y, Segel R, Turner D. Thiopurine S-methyltransferase (TPMT) activity is better determined by biochemical assay versus genotyping in the Jewish population. Dig Dis Sci 2014; 59:1207-12. [PMID: 24390675 DOI: 10.1007/s10620-013-3008-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 12/17/2013] [Indexed: 12/19/2022]
Abstract
BACKGROUND Thiopurine S-methyltransferase (TPMT) is a key enzyme that deactivates thiopurines, into their inactive metabolite, 6-methylmercaptopurine. Intermediate and low TPMT activity may lead to leukopenia following thiopurine treatment. The aim of this study was to determine TPMT activity and TPMT alleles (genotype-phenotype correlation) in Jews, aiming to develop an evidence-based pharmacogenetic assay for this population. METHODS TPMT activity was determined in 228 Jewish volunteers by high performance liquid chromatography. Common allelic variants in the Caucasian population [TPMT*2 (G238C), TPMT *3A (G460A and A719G), TPMT* 3B (G460A) and TPMT*3C (A719G)] were tested. Phenotype-genotype correlation was examined and discordant cases were fully sequenced to identify novel genetic variants. RESULTS Mean TPMT activity was 15.4 ± 4 U/ml red blood cells (range 1-34). Intermediate activity was found in 33/228 (14%) subjects and absent activity was found in one sample (0.4%). Only eight individuals (3.5% of the entire cohort and 24% of those with intermediate/low activity) were identified as carriers of a TPMT genetic variant, all of whom had the TPMT*3A allele. Sequencing the entire TPMT coding region and splice junctions in the remainder of the discordant cases did not reveal any novel variants. CONCLUSION Genotyping TPMT in Jews yields a much lower rate of variants than identified in the general Caucasian population. We conclude that a biochemical assay to determine TPMT enzymatic activity should be performed in Jews before starting thiopurine treatment in order to identify low activity subjects.
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Affiliation(s)
- Yair Kasirer
- Pediatric Gastroenterology and Nutrition Unit, Shaare Zedek Medical Center, The Hebrew University, P.O. B 3235, 91031, Jerusalem, Israel
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Beswick L, Friedman AB, Sparrow MP. The role of thiopurine metabolite monitoring in inflammatory bowel disease. Expert Rev Gastroenterol Hepatol 2014; 8:383-92. [PMID: 24684593 DOI: 10.1586/17474124.2014.894878] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Thiopurines are the mainstay of medical management in inflammatory bowel disease (IBD), especially in the maintenance of disease remission. Given the limited IBD armamentarium it is important to optimize each therapy before switching to an alternative drug. Conventional weight based dosing of thiopurines in IBD leads to intolerance or inefficacy in many patients. More recently increased knowledge of their metabolism has allowed for dose optimization using thiopurine metabolite levels, namely 6-thioguanine nucleotides and 6-methylmercaptopurine, with the potential for improved outcomes in patients with IBD. This review will outline the current understanding of thiopurine metabolism and pharmacogenomics and will describe the clinical application of this knowledge in the optimization of thiopurines in individual patients.
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Affiliation(s)
- Lauren Beswick
- Department of Gastroenterology, Alfred Health and Monash University, Commercial Road, Melbourne, 3004 Victoria, Australia
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Doré M, Frenette AJ, Mansour AM, Troyanov Y, Bégin J. Febuxostat as a novel option to optimize thiopurines' metabolism in patients with inadequate metabolite levels. Ann Pharmacother 2014; 48:648-51. [PMID: 24523395 DOI: 10.1177/1060028014521389] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
OBJECTIVE To report the use of febuxostat in order to potentiate thiopurines' metabolism in a patient on azathioprine (AZA) therapy with low metabolite 6-thioguanine nucleotides (6-TGN) levels and elevated metabolite 6-methylmercaptopurine (6-MMP) levels. CASE SUMMARY A 44-year-old woman with a history of anti-signal recognition particle necrotizing myopathy was treated with AZA-allopurinol combination therapy. When she developed an atypical drug-induced hypersensitivity syndrome, allopurinol was replaced by the new xanthine oxidase (XO) inhibitor febuxostat, at a daily dose of 40 mg. Febuxostat-AZA combination was successful with 6-TGN reaching therapeutic levels while 6-MMP levels remained low. After 5 months, she developed similar manifestations that she had presented on AZA-allopurinol combination. Febuxostat and AZA were then stopped. DISCUSSION AZA and 6-MP are both inactive pro-drugs that undergo a complex metabolic transformation leading to active 6-TGN and potentially hepatotoxic 6-MMP. Some patients with unfavorable thiopurine metabolism might benefit from addition of XO inhibitor allopurinol in order to potentiate 6-TGN and reduce 6-MMP levels. It is likely that febuxostat, via its XO inhibition, would exhibit the same effect on thiopurines' metabolism. CONCLUSION It has been shown that low dose of febuxostat was able to prevent hypermethylation and to potentiate 6-TGN levels in an AZA-treated patient. Thus, febuxostat could be useful in optimizing thiopurines' metabolism, but more data are needed before this practice can be recommended. The mechanisms by which febuxostat optimizes thiopurines' metabolism remain to be confirmed. Also, the optimal dose of febuxostat for this use remains to be determined.
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Affiliation(s)
- Maxime Doré
- Hôpital du Sacré-Coeur de Montréal, Montreal, Quebec, Canada
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Improved method for therapeutic drug monitoring of 6-thioguanine nucleotides and 6-methylmercaptopurine in whole-blood by LC/MSMS using isotope-labeled internal standards. Ther Drug Monit 2013; 35:313-21. [PMID: 23666567 DOI: 10.1097/ftd.0b013e318283ed5d] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVES Thiopurine drugs (azathioprine, 6-mercaptopurine) show wide interindividual variability and a narrow therapeutic range thus making therapeutic monitoring of their active metabolite 6-thioguanine nucleotides (6-TGN) desirable. We improved the currently available laborious and complex methodology of therapeutic drug monitoring of 6-TGN and the metabolite 6-methylmercaptopurine (6-MMP) in washed erythrocytes (ery) based on a whole-blood method. METHODS The analytes were hydrolyzed and extracted from 25-µL ethylenediaminetetraacetic acid-anticoagulated whole-blood spiked with isotope labeled 6-TG-C2N and 6-MMP-d3 internal standards. Chromatography was performed in 5.1 minutes on a C18 reverse phase column followed by detection via electrospray interface-coupled API 4000 mass spectrometer set up in the positive multiple reaction monitoring mode. The hemoglobin concentration was measured in 20 µL of the original sample (AHD575 method), and the results were standardized to 120 g/L of hemoglobin. RESULTS Calibration curves were linear with r > 0.999 (6-TGN and 6-MMP up to 10,000 pmol/0.2 mL). The limit of quantification was 30 pmol/0.2 mL for 6-TGN and 6-MMP. Intraassay and interassay imprecision was <7.5% at 3 tested levels for 6-TGN and 6-MMP, respectively. Method comparisons were as follows: Ery 6-TGN: y = 1.3x - 11 and ery 6-MMP y = 1.1x - 124. CONCLUSIONS The new method compares favorably with established ones, allowing for rapid single run determination of 6-TGN and 6-MMP from <50 µL of fresh or frozen whole blood. Linearity and limits of quantification cover the clinically relevant range. Variability during sample preparation and matrix effects are compensated by the use of isotope-labeled internal standards. The whole-blood method is hemoglobin standardized to avoid falsely low results in the case of anemia. The method correlates well with 6-TGN measured in washed erythrocytes, but it requires significantly less hands-on time. Preliminary therapeutic ranges for the most common indications of azathioprine and 6-MP are provided.
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Stocco G. Commentary. Clin Chem 2013; 59:1027. [DOI: 10.1373/clinchem.2012.200428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Gabriele Stocco
- Department of Life Sciences, University of Trieste, Trieste, Italy
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Chouchana L, Roche D, Jian R, Beaune P, Loriot MA. Poor Response to Thiopurine in Inflammatory Bowel Disease: How to Overcome Therapeutic Resistance? Clin Chem 2013; 59:1023-6. [DOI: 10.1373/clinchem.2012.195750] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Laurent Chouchana
- Assistance publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Biochimie, Pharmacogénétique et Oncologie Moléculaire, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
- INSERM UMR-S775, Paris, France
| | - Denis Roche
- Assistance publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Biochimie, Pharmacogénétique et Oncologie Moléculaire, Paris, France
| | - Raymond Jian
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
- Assistance publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Hepato-gastro-enterologie et endoscopie digestive, Paris, France
| | - Philippe Beaune
- Assistance publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Biochimie, Pharmacogénétique et Oncologie Moléculaire, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
- INSERM UMR-S775, Paris, France
| | - Marie-Anne Loriot
- Assistance publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Biochimie, Pharmacogénétique et Oncologie Moléculaire, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
- INSERM UMR-S775, Paris, France
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Blaker PA, Arenas-Hernandez M, Smith MA, Shobowale-Bakre EA, Fairbanks L, Irving PM, Sanderson JD, Marinaki AM. Mechanism of allopurinol induced TPMT inhibition. Biochem Pharmacol 2013; 86:539-47. [PMID: 23770457 DOI: 10.1016/j.bcp.2013.06.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 06/04/2013] [Accepted: 06/05/2013] [Indexed: 12/16/2022]
Abstract
Up to 1/5 of patients with wildtype thiopurine-S-methyltransferase (TPMT) activity prescribed azathioprine (AZA) or mercaptopurine (MP) demonstrate a skewed drug metabolism in which MP is preferentially methylated to yield methylmercaptopurine (MeMP). This is known as thiopurine hypermethylation and is associated with drug toxicity and treatment non-response. Co-prescription of allopurinol with low dose AZA/MP (25-33%) circumvents this phenotype and leads to a dramatic reduction in methylated metabolites; however, the biochemical mechanism remains unclear. Using intact and lysate red cell models we propose a novel pathway of allopurinol mediated TPMT inhibition, through the production of thioxanthine (TX, 2-hydroxymercaptopurine). In red blood cells pre-incubated with 250 μM MP for 2h prior to the addition of 250 μM TX or an equivalent volume of Earle's balanced salt solution, there was a significant reduction in the concentration of MeMP detected at 4h and 6h in cells exposed to TX (4 h, 1.68, p=0.0005, t-test). TX acts as a direct TPMT inhibitor with an apparent Ki of 0.329 mM. In addition we have confirmed that the mechanism is relevant to in vivo metabolism by demonstrating raised urinary TX levels in patients receiving combination therapy. We conclude that the formation of TX in patients receiving combination therapy with AZA/MP and allopurinol, likely explains the significant reduction of methylated metabolites due to direct TPMT inhibition.
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Affiliation(s)
- P A Blaker
- Department of Gastroenterology, Guy's and St Thomas' NHS Hospitals Foundation Trust, London, UK.
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Gene expression and thiopurine metabolite profiling in inflammatory bowel disease - novel clues to drug targets and disease mechanisms? PLoS One 2013; 8:e56989. [PMID: 23437289 PMCID: PMC3578787 DOI: 10.1371/journal.pone.0056989] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 01/16/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND AND AIMS Thiopurines are effective to induce and maintain remission in inflammatory bowel disease (IBD). The methyl thioinosine monophosphate (meTIMP)/6-thioguanine nucleotide (6-TGN) concentration ratio has been associated with drug efficacy. Here we explored the molecular basis of differences in metabolite profiles and in relation to disease activity. METHODS Transcriptional profiles in blood samples from an exploratory IBD-patient cohort (n = 21) with a normal thiopurine S-methyltransferase phenotype and meTIMP/6-TGN ratios >20, 10.0-14.0 and ≤4, respectively, were assessed by hybridization to microarrays. Results were further evaluated with RT qPCR in an expanded patient cohort (n = 54). Additionally, 30 purine/thiopurine related genes were analysed separately. RESULTS Among 17 genes identified by microarray-screening, there were none with a known relationship to pathways of purines/thiopurines. For nine of them a correlation between expression level and the concentration of meTIMP, 6-TGN and/or the meTIMP/6-TGN ratio was confirmed in the expanded cohort. Nine of the purine/thiopurine related genes were identified in the expanded cohort to correlate with meTIMP, 6-TGN and/or the meTIMP/6-TGN ratio. However, only small differences in gene expression levels were noticed over the three different metabolite profiles. The expression levels of four genes identified by microarray screening (PLCB2, HVCN1, CTSS, and DEF8) and one purine/thiopurine related gene (NME6) correlated significantly with the clinical activity of Crohn's disease. Additionally, 16 of the genes from the expanded patient cohort interacted in networks with candidate IBD susceptibility genes. CONCLUSIONS Seventeen of the 18 genes which correlated with thiopurine metabolite levels also correlated with disease activity or participated in networks with candidate IBD susceptibility genes involved in processes such as purine metabolism, cytokine signaling, and functioning of invariant natural killer T cells, T cells and B cells. Therefore, we conclude that the identified genes to a large extent are related to drug targets and disease mechanisms of IBD.
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Blaker PA, Arenas-Hernandez M, Marinaki AM, Sanderson JD. The pharmacogenetic basis of individual variation in thiopurine metabolism. Per Med 2012; 9:707-725. [DOI: 10.2217/pme.12.85] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Thiopurines are an important class of immunosuppressive therapy, which have been used in clinical practice for over 50 years. Despite this extensive experience many of the pharmacodynamic and pharmacokinetic properties of these drugs remain unknown. As a consequence there is often no clear explanation for the individual variation in response to treatment, both in terms of efficacy or adverse drug reactions. This review, which emphasizes practice in gastroenterology, summarizes the current understanding of thiopurine drug metabolism and highlights the role of nongenetic and genetic factors other than TPMT, which should be a focus for future research. Correlation of polymorphic variations in these genes with clinical outcomes is expected to clarify the basis for interindividual differences in thiopurine metabolism and enable a more personalized approach to therapy.
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Affiliation(s)
- Paul Andrew Blaker
- Department of Gastroenterology, 1st Floor College House, St Thomas’ Hospital, Westminster Bridge Road, London, SE1 7EH, London, UK
| | - Monica Arenas-Hernandez
- The Purine Research Laboratory, Guy’s & St Thomas’ Hospitals NHS Foundation Trust , London, UK
| | - Anthony Marin Marinaki
- The Purine Research Laboratory, Guy’s & St Thomas’ Hospitals NHS Foundation Trust , London, UK
| | - Jeremy David Sanderson
- Department of Gastroenterology, 1st Floor College House, St Thomas’ Hospital, Westminster Bridge Road, London, SE1 7EH, London, UK
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González-Lama Y, Gisbert JP. Letter: TPMT - not all that glitters is gold. Aliment Pharmacol Ther 2012; 36:208-9; author reply 209-10. [PMID: 22703467 DOI: 10.1111/j.1365-2036.2012.05148.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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