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Desai D. Therapeutic drug monitoring in inflammatory bowel disease: A practical approach. Indian J Gastroenterol 2024; 43:93-102. [PMID: 38329599 DOI: 10.1007/s12664-024-01527-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Accepted: 01/03/2024] [Indexed: 02/09/2024]
Abstract
The global burden of inflammatory bowel diseases (IBD) is estimated at 4.9 million and the global prevalence exceeds 0.3%. Multiple newer therapeutic agents have broadened the options for the therapy of IBD in the last three decades. Thiopurines, however, have retained their place as maintenance therapy in IBD, especially in resource-constrained setting. But thiopurines have narrow therapeutic range, often needing discontinuation due to side effects or lack of efficacy. Biologic agents revolutionized the treatment of IBD, but the efficacy is lost in 50% of patient after one year. These outcomes are often due to inadequate drug concentrations that may lead to the development of antibodies as well as pharmacodynamic failure. Therapeutic drug monitoring (TDM) was proposed to reduce loss of response and to optimize the therapy in patients on thiopurine and biologic therapy. TDM is based on exposure-response relationship, suggesting a positive correlation between elevated serum anti-TNF concentrations and favorable therapeutic outcomes. TDM has multiple facets. This article discusses the benefits, evidence and limitations of TDM. The practical use of TDM in clinical practice is highlighted. Newer developments in the field and their relevance in practice are discussed.
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Affiliation(s)
- Devendra Desai
- P D Hinduja Hospital, Veer Savarkar Marg, Mahim, Mumbai, 400 016, India.
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2
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Intestinal Microbiota-Mediated Biotransformations Alter the Pharmacokinetics of the Major Metabolites of Azathioprine in Rats after Oral Administration. Drug Metab Pharmacokinet 2022; 45:100458. [DOI: 10.1016/j.dmpk.2022.100458] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 02/24/2022] [Accepted: 03/11/2022] [Indexed: 11/22/2022]
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Candels LS, Rahim MN, Shah S, Heneghan MA. Towards personalised medicine in autoimmune hepatitis: Measurement of thiopurine metabolites results in higher biochemical response rates. J Hepatol 2021; 75:324-332. [PMID: 33872691 DOI: 10.1016/j.jhep.2021.03.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 03/17/2021] [Accepted: 03/18/2021] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Patients with autoimmune hepatitis (AIH) usually receive maintenance therapy with thiopurines, such as azathioprine (AZA) or mercaptopurine. Genetic polymorphisms in AZA metabolism can lead to variations in thioguanine nucleotide (TGN) and 6-methylmercaptopurine, both of which can cause adverse drug reactions (ADRs). In inflammatory bowel disease, a therapeutic TGN range (225-450 pmol/8x108 erythrocytes) has been identified to optimise effectiveness. We evaluated the benefits of a personalised medicine approach to thiopurine dosing, in comparison to standard weight-based dosing. METHODS A retrospective matched cohort study of 214 patients with AIH who were seen at King's College between 1999-2019 was performed. Metabolite levels were measured in 109 patients. The control group included 105 patients on weight-based thiopurine dosing with no metabolite monitoring. RESULTS Biochemical response (BR) occurred more frequently at 6-month follow-up in patients with metabolite monitoring compared to those on a weight-based regimen (77% vs. 60%, p = 0.008). This remained true with data analysis based on clinicians who measure metabolites and those who do not (BR at 6 months: 84% vs. 64%, p = 0.016). Patients with BR had TGN levels within the therapeutic range of 225-450 pmol/8x108 erythrocytes significantly more often than those who failed to achieve or lost BR (40% vs. 13%, p <0.0001). Moreover, TGN levels within the pre-defined therapeutic range predicted more stable disease within 6 months of testing compared to levels outside the range (p <0.0001). A high proportion of patients with sub-therapeutic TGN levels (75-225 pmol/8x108 erythrocytes) remained in BR (75% vs. 81%, p = 0.589) with fewer ADRs (44% vs. 86%, p = 0.0002) when compared to patients with therapeutic TGN levels. CONCLUSION A strategy of personalised medicine using metabolite levels can optimise treatment regimens in AIH, resulting in fewer ADRs whilst maintaining BR. LAY SUMMARY This study looked to see if measuring the breakdown products of a medication used in autoimmune hepatitis increases the chances of gaining good control of the disease, when compared to a group of patients who were on a dose of this medication based on their weight. A group of 214 patients with autoimmune hepatitis were split into 2 groups: roughly half had their medication dose adjusted according to measurements of breakdown products in the blood, whilst the other half received their weight-based dose as normal. The results confirmed that using a personalised approach and checking drug breakdown products resulted in fewer side effects and potentially improved control of disease.
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Affiliation(s)
- Lena S Candels
- Institute of Liver Studies, King's College Hospital, London, SE5 9RS, UK; Department of Internal Medicine III, University Hospital RWTH Aachen, 52074 Aachen, Germany
| | - Mussarat N Rahim
- Institute of Liver Studies, King's College Hospital, London, SE5 9RS, UK; School of Transplantation, Immunology and Mucosal Biology, Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Sital Shah
- Institute of Liver Studies, King's College Hospital, London, SE5 9RS, UK
| | - Michael A Heneghan
- Institute of Liver Studies, King's College Hospital, London, SE5 9RS, UK; School of Transplantation, Immunology and Mucosal Biology, Faculty of Life Sciences and Medicine, King's College London, London, UK; European Reference Network - Hepatological Diseases (ERN RARE-LIVER).
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van Hoeve K, Vermeire S. Thiopurines in Pediatric Inflammatory Bowel Disease: Current and Future Place. Paediatr Drugs 2020; 22:449-461. [PMID: 32797366 DOI: 10.1007/s40272-020-00411-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Thiopurines have been widely used to maintain steroid-free remission in children with inflammatory bowel disease (IBD). However, within the expanding treatment armamentarium, the role of these non-selective immunomodulators has been questioned, especially in pediatric patients, who often present with a more aggressive disease course, which can impact growth and development. The less favorable safety but also inferior efficacy profile associated with thiopurines, in contrast to the newer biological therapies, has interfered with their use. The future place of thiopurines in the management of childhood IBD, therefore, needs revisiting. This review provides a practical overview on the historical and current use of thiopurines in pediatric IBD with specific attention for thiopurine S-methyltransferase testing and monitoring of thiopurine metabolite levels as an approach to improve outcomes. We also give a personal expert opinion on the future role of these drugs in childhood IBD.
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Affiliation(s)
- Karen van Hoeve
- Department of Pediatric Gastroenterology and Hepatology and Nutrition, University Hospitals Leuven, KU Leuven, Leuven, Belgium.,TARGID, Department of Chronic Diseases and Metabolism (CHROMETA), KU Leuven, Leuven, Belgium
| | - Séverine Vermeire
- TARGID, Department of Chronic Diseases and Metabolism (CHROMETA), KU Leuven, Leuven, Belgium. .,Department of Gastroenterology and Hepatology, University Hospitals Leuven, KU Leuven, Leuven, Belgium.
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Thiopurines' Metabolites and Drug Toxicity: A Meta-Analysis. J Clin Med 2020; 9:jcm9072216. [PMID: 32668748 PMCID: PMC7408995 DOI: 10.3390/jcm9072216] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 07/06/2020] [Accepted: 07/09/2020] [Indexed: 12/13/2022] Open
Abstract
Many questions remain unanswered regarding therapeutic drug monitoring (TDM) utility with thiopurines. This study aims to establish a relationship between thiopurines' metabolites and drug toxicity. We performed a systematic review with inclusion of studies evaluating the relationship between thiopurines' metabolites and drug toxicity. Meta-analysis of mean difference (MD), correlations and odds ratio (OR) was performed. We identified 21,240 records, 72 of which were eligible for meta-analysis. Levels of 6-thioguanine nucleotides (6-TGN) were higher in patients with leukopenia (MD 127.06 pmol/8 × 108 RBC) and gastrointestinal intolerance (MD 201.46 pmol/8 × 108 RBC), and lower in patients with hepatotoxicity (MD -40.6 pmol × 108 RBC). We established a significant correlation between 6-TGN and leukocytes (r = -0.21), neutrophils (r = -0.24) and alanine aminotransferase levels (r = -0.24). OR for leukopenia in patients with elevated 6-TGN was 4.63 (95%CI 2.24; 9.57). An optimal cut-off of 135 pmol/8 × 108 RBC for leukopenia was calculated (sensitivity 75.4%; specificity 46.4%). 6-methylmercaptopurine ribonucleotides (6-MMPR) were significantly associated with hepatotoxicity (MD 3241.2 pmol/8 × 108 RBC; OR 4.28; 95%CI 3.20; 5.71). Levels of 6-MMPR measured in the first 8 weeks of treatment were associated with leukopenia. We conclude that TDM could be used to prevent thiopurines' toxicity. As optimal metabolites level may vary according to indication, physicians may adapt posology to decrease toxicity without compromising efficacy.
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6
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Czaja AJ. Review article: opportunities to improve and expand thiopurine therapy for autoimmune hepatitis. Aliment Pharmacol Ther 2020; 51:1286-1304. [PMID: 32363674 DOI: 10.1111/apt.15743] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 03/07/2020] [Accepted: 03/31/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND Thiopurines in combination with glucocorticoids are used as first-line, second-line and maintenance therapies in autoimmune hepatitis and opportunities exist to improve and expand their use. AIMS To describe the metabolic pathways and key factors implicated in the efficacy and toxicity of the thiopurine drugs and to indicate the opportunities to improve outcomes by monitoring and manipulating metabolic pathways, individualising dosage and strengthening the response. METHODS English abstracts were identified in PubMed by multiple search terms. Full-length articles were selected for review, and secondary and tertiary bibliographies were developed. RESULTS Thiopurine methyltransferase activity and 6-tioguanine (6-thioguanine) nucleotide levels influence drug efficacy and safety, and they can be manipulated to improve treatment response and prevent myelosuppression. Methylated thiopurine metabolites are associated with hepatotoxicity, drug intolerance and nonresponse and their production can be reduced or bypassed. Universal pre-treatment assessment of thiopurine methyltransferase activity and individualisation of dosage to manipulate metabolite thresholds could improve outcomes. Early detection of thiopurine resistance by metabolite testing, accurate estimations of drug onset and strength by surrogate markers and adjunctive use of allopurinol could improve the management of refractory disease. Dose-restricted tioguanine (thioguanine) could expand treatment options by reducing methylated metabolites, increasing the bioavailability of 6-tioguanine nucleotides and ameliorating thiopurine intolerance or resistance. CONCLUSIONS The efficacy and safety of thiopurines in autoimmune hepatitis can be improved by investigational efforts that establish monitoring strategies that allow individualisation of dosage and prediction of outcome, increase bioavailability of the active metabolites and demonstrate superiority to alternative agents.
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Affiliation(s)
- Albert J Czaja
- Division of Gastroenterology and Hepatology, Mayo Clinic College of Medicine and Science, Rochester, MN, USA
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Spencer E, Norris E, Williams C, Dubinsky MC. The Impact of Thiopurine Metabolite Monitoring on the Durability of Thiopurine Monotherapy in Pediatric IBD. Inflamm Bowel Dis 2019; 25:142-149. [PMID: 29920603 DOI: 10.1093/ibd/izy216] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2017] [Indexed: 12/11/2022]
Abstract
BACKGROUND Thiopurine metabolite monitoring to proactively dose optimize to achieve therapeutic levels has not been used consistently, and it is unclear if this would lead to better outcomes. We aimed to compare 6-month outcomes between standard and optimized dosing strategies and define long-term predictors of thiopurine durability. METHODS Two hundred sixteen pediatric IBD patients with at least 2 6-thioguanine nucleotide (6-TGN) levels were grouped for analysis by start dose: >2.5 mg/kg/day AZA (group 1) or <2.5 mg/kg/day (group 2) and further subgrouped depending on whether dosing was optimized to achieve 6-TGN >235 pmol/8 × 108 RBC. The metabolites, 6TGN and 6MMP, were univariate and multivariate analyses tested associations among metabolite levels, laboratory data, and the primary outcome of 6-month steroid-free clinical remission (SFR) (HBI ≤4 for CD; partial Mayo Score [pMS] ≤2 for UC). Thiopurine durability was measured using Kaplan Maier survival analysis. RESULTS 6-MP, azathioprine, pediatrics, therapeutic drug monitoring, pediatrics were measured a median 59 (43-76) days after initiation of thiopurine. Both dosing strategies led to similar initial 6-TGN levels (group 1 = median 209 [IQR: 155-272] with 25% of patients >235; group 2 = 196 [139-274] with 29% >235). Steroid-free clinical remission was achieved in 74% of the 180 still on thiopurines at 6 months. Start dose was not associated with 6-month SFR-73% in group 1 and 77% in group 2 within those on thiopurines at 6 months (P = 0.61). Fixed- and optimized-dosing subgroups had similar 6-month 6-TGN levels, SFR rate, and percentage 6-TGN > 235. Only 6-TGN level >235 at 6 months predicted thiopurine durability (3 years [1.7-7.7] vs 2.5 years [0.83-5]; log-rank P < 0.001), and this did not retain significant in a multivariate model. Initial dosing strategy, first 6-TGN level, 6-month SFR, 6MMP:6TGN ratio, and delta-MCV did not predict durability. The rate of adverse events was 22%. CONCLUSIONS Steroid-free clinical remission and 6-TGN levels at 6 months were no different between a standardized, fixed dosing strategy and a metabolite-driven, optimized dosing strategy.
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Affiliation(s)
- Elizabeth Spencer
- Icahn School of Medicine, Mt. Sinai Hospital, Susan and Leonard Feinstein IBD Center, New York, New York, USA
| | - Evan Norris
- Icahn School of Medicine, Mt. Sinai Hospital, Susan and Leonard Feinstein IBD Center, New York, New York, USA
| | - Chadwick Williams
- Dalhousie University and Memorial University of Newfoundland, Saint John Regional Hospital, Saint John, New Brunswick, Canada
| | - Marla C Dubinsky
- Icahn School of Medicine, Mt. Sinai Hospital, Susan and Leonard Feinstein IBD Center, New York, New York, USA
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Citterio-Quentin A, El Mahmoudi A, Perret T, Conway A, Ryan A, Beringer A, Lachaux A, Boulieu R. Red Blood cell IMPDH activity in adults and children with or without azathioprine: Relationship between thiopurine metabolites, ITPA and TPMT activities. Basic Clin Pharmacol Toxicol 2018; 124:600-606. [PMID: 30451390 DOI: 10.1111/bcpt.13176] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 11/11/2018] [Indexed: 01/11/2023]
Abstract
Inosine monophosphate dehydrogenase (IMPDH) is considered as the limiting enzyme of thiopurine metabolism for the formation of 6-thioguanine nucleotides (6-TGN). No data are available on the influence of RBC IMPDH activity on the metabolism of thiopurine drugs in individuals with IBD. The aims of this study were as follows: (a) to carry out a phenotypic study of RBC IMPDH activity in adults and children treated or not with azathioprine (AZA) for autoimmune diseases, and (b) to investigate the relationship between the activities of IMPDH, thiopurine metabolites, inosine triphosphatase (ITPA) and thiopurine methyltransferase (TPMT). IMPDH activity was determined in 97 adults and 67 children treated or not with AZA. 6-Thioguanine nucleotides (6-TGN), 6-methylmercaptopurine nucleotide (6-MeMPN) levels, and ITPA as well as TPMT activities were measured in RBCs by HPLC. Using the Gaussian mixture model, distribution of IMPDH activity was evaluated. Influence of age, sex and AZA treatment on IMPDH activity was also assessed. A bimodal distribution in IMPDH activity was found with 87% of patients exhibiting normal activity and 13% of patients with high activity. No influence of age, sex and AZA therapy was found. There is no relationship between TPMT, ITPA and IMPDH activities. A negative correlation between IMPDH activity and 6-MeMPN was shown in adults and children (rs = -0.335 P = 0.014 and rs = -0.383 P = 0.012, respectively). Our results suggest that AZA-treated patients exhibiting lower IMPDH activity could have higher Me-6MPN levels with higher risk of hepatotoxicity. We demonstrated that RBC matrix could be an interesting alternative to lymphocyte matrix to monitor thiopurine metabolites and enzyme activity.
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Affiliation(s)
- Antony Citterio-Quentin
- Clinical Pharmacy, Pharmacokinetics and Drug Evaluation, Université de Lyon, Université Lyon 1, France.,Edouard Herriot Hospital, Laboratory of Medical Biology Multisites of University Hospital of Lyon, Pharmaco-Toxicology Unit, Hospices Civils de Lyon, Lyon, France
| | - Amal El Mahmoudi
- Clinical Pharmacy, Pharmacokinetics and Drug Evaluation, Université de Lyon, Université Lyon 1, France.,Edouard Herriot Hospital, Laboratory of Medical Biology Multisites of University Hospital of Lyon, Pharmaco-Toxicology Unit, Hospices Civils de Lyon, Lyon, France
| | - Thibault Perret
- Clinical Pharmacy, Pharmacokinetics and Drug Evaluation, Université de Lyon, Université Lyon 1, France.,Edouard Herriot Hospital, Laboratory of Medical Biology Multisites of University Hospital of Lyon, Pharmaco-Toxicology Unit, Hospices Civils de Lyon, Lyon, France
| | - Anthony Conway
- Clinical Pharmacy, Pharmacokinetics and Drug Evaluation, Université de Lyon, Université Lyon 1, France.,School of Pharmacy and Pharmaceuticals Sciences, Trinity College Dublin, Dublin, Ireland
| | - Aishling Ryan
- Clinical Pharmacy, Pharmacokinetics and Drug Evaluation, Université de Lyon, Université Lyon 1, France.,School of Pharmacy and Pharmaceuticals Sciences, Trinity College Dublin, Dublin, Ireland
| | - Audrey Beringer
- Clinical Pharmacy, Pharmacokinetics and Drug Evaluation, Université de Lyon, Université Lyon 1, France.,Edouard Herriot Hospital, Laboratory of Medical Biology Multisites of University Hospital of Lyon, Pharmaco-Toxicology Unit, Hospices Civils de Lyon, Lyon, France
| | - Alain Lachaux
- Pediatric Gastroenterology Unit, Hôpital Femme Mère Enfant (HFME), Lyon, France
| | - Roselyne Boulieu
- Clinical Pharmacy, Pharmacokinetics and Drug Evaluation, Université de Lyon, Université Lyon 1, France.,Edouard Herriot Hospital, Laboratory of Medical Biology Multisites of University Hospital of Lyon, Pharmaco-Toxicology Unit, Hospices Civils de Lyon, Lyon, France
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ITPA Activity in Adults and Children Treated With or Without Azathioprine: Relationship Between TPMT Activity, Thiopurine Metabolites, and Co-medications. Ther Drug Monit 2018. [PMID: 28650902 DOI: 10.1097/ftd.0000000000000430] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The implication of inosine triphosphate pyrophosphatase (ITPA) on thiopurine drug response variability has been investigated but little data are available on its role on thiopurine metabolites. The ability of ITPA to modify the thiopurine metabolite levels is currently used to optimize azathioprine (AZA) therapy in relation to thiopurine S-methyltransferase (TPMT) activity, the aim of this study is to investigate ITPA phenotype in a large population and to evaluate the relation between ITPA and TPMT activities and thiopurine metabolites. METHODS ITPA activity was determined in 183 adults and 138 children with or without AZA therapy. 6-thioguanine nucleotides (6-TGN), 6-methylmercaptopurine nucleotides (6-MeMPN) levels, and ITPA as well as TPMT activities were measured in red blood cells. Using the Gaussian mixture model, distribution of ITPA activity was evaluated. Intraindividual variability and influence of age, sex, AZA treatment and associated co-medications on ITPA activity were also assessed. RESULTS This retrospective study shows a quadrimodal distribution in ITPA activity. No influence of age, sex, AZA therapy, and co-medications was found. In adults, ITPA activity was not significantly associated with 6-TGN or 6-MeMPN concentrations, whereas a weak negative correlation was observed with 6-MeMPN levels in pediatric populations (rs = -0.261; P = 0.024). A weak positive correlation was observed between ITPA and TPMT activities in children (rs = 0.289; P = 0.001). CONCLUSIONS ITPA activity was poorly influenced by nongenetic parameters and has no influence on 6-TGN and 6-MeMPN concentrations in adults and only a weak correlation with 6-MeMPN and TPMT activity in children. These results demonstrate that ITPA is not a rate-limiting enzyme in the formation of 6-TGN but suggest that a decrease in ITPA activity in children may be a risk factor for accumulation of 6-MeMPN in cells.
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Carman N, Mack DR, Benchimol EI. Therapeutic Drug Monitoring in Pediatric Inflammatory Bowel Disease. Curr Gastroenterol Rep 2018; 20:18. [PMID: 29623442 DOI: 10.1007/s11894-018-0623-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
PURPOSE OF REVIEW Therapeutic drug monitoring (TDM) has emerged as a useful tool to optimize the use of drug therapies in adults with inflammatory bowel disease (IBD), including both Crohn's disease (CD) and ulcerative colitis (UC), especially during the use of biological therapies, for which the pharmacokinetics and pharmacodynamics are highly variable among patients. Fewer data exist in children. This review examines the current literature on TDM in pediatric IBD. RECENT FINDINGS Drug clearance is affected by a number of patient and disease factors. For thiopurines, adjusting dosing by monitoring 6-thioguanine (6TGN) and 6-methylmercaptopurine ((6MMP) levels is demonstrated to maximize response and minimize toxicity, while monitoring metabolite levels when treating with anti-tumor necrosis factor (anti-TNF) remain controversial. While in adults the use of TDM in the setting of loss of response to anti-TNF therapy is established, in children, only a small number of studies exist, but these too have encouraging results. There are however, conflicting data regarding the optimal timing of TDM, comparing "reactive" monitoring and "proactive" monitoring. No such data exist in pediatrics. TDM is cost-effective, and dose reduction may represent a safety benefit. There are limited adult data for use of TDM for the newer biologics, vedolizumab and ustekinumab, but early results suggest similarly promising utility. The use of TDM in pediatric IBD is increasing in clinical practice, with similar efficacy to adults demonstrated in children with loss of response to anti-TNF therapy. More prospective studies are needed in children to examine proactive monitoring and utility of TDM with newer biologics.
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Affiliation(s)
- Nicholas Carman
- CHEO Inflammatory Bowel Disease Centre, Division of Gastroenterology, Hepatology and Nutrition, Children's Hospital of Eastern Ontario, 401 Smyth Road, Ottawa, ON, K1H 8L1, Canada.
- Department of Pediatrics, University of Ottawa, Ottawa, ON, Canada.
| | - David R Mack
- CHEO Inflammatory Bowel Disease Centre, Division of Gastroenterology, Hepatology and Nutrition, Children's Hospital of Eastern Ontario, 401 Smyth Road, Ottawa, ON, K1H 8L1, Canada
- Department of Pediatrics, University of Ottawa, Ottawa, ON, Canada
| | - Eric I Benchimol
- CHEO Inflammatory Bowel Disease Centre, Division of Gastroenterology, Hepatology and Nutrition, Children's Hospital of Eastern Ontario, 401 Smyth Road, Ottawa, ON, K1H 8L1, Canada
- Department of Pediatrics, University of Ottawa, Ottawa, ON, Canada
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, ON, Canada
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Citterio-Quentin A, Moulsma M, Gustin MP, Lachaux A, Boulieu R. ITPA Activity in Children Treated by Azathioprine: Relationship to the Occurrence of Adverse Drug Reactions and Inflammatory Response. Basic Clin Pharmacol Toxicol 2018; 122:588-595. [PMID: 29327413 DOI: 10.1111/bcpt.12958] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 12/27/2017] [Indexed: 12/13/2022]
Abstract
Azathioprine (AZA), a thiopurine drug, is widely used in the treatment of children with immunological diseases such as inflammatory bowel disease (IBD) and autoimmune hepatitis (AIH); however, interindividual variability in the occurrence of adverse drug reactions (ADRs) and drug response is observed. This study investigated (i) the relationships between inosine triphosphate pyrophosphatase (ITPA) activity, an enzyme involved in thiopurine metabolism, and the occurrence of ADRs in children with immunological disease on AZA therapy, and (ii) the relationship between ITPA activity and the inflammatory activity observed in children with IBD. ITPA and TPMT activities were determined in 106 children with immunological disease on AZA therapy. Markers of hepatotoxicity, myelotoxicity, pancreatitis and inflammation as well as clinical information were retrospectively collected during regular medical visits. No significant association was found between ITPA activity and hepatotoxicity or clinical ADRs such as cutaneous reactions, arthralgia, flulike symptoms and gastrointestinal disorders. Concerning myelotoxicity, a significant relation was observed between ITPA activity and RBC mean corpuscular volume (MCV; p=0.003). This observation may be related to the significant relationship found between high ITPA activity and the increase in γ-globulin level reflecting inflammation (p=0.005). In our study, ITPA activity was not associated with occurrence of ADRs, but a relationship between high ITPA activity and γ-globulin, a marker of inflammation, was found in children with IBD. Therefore, measurement of ITPA activity may help to identify children with IBD predisposed to residual inflammation on AZA therapy. Further prospective studies are needed to confirm this result.
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Affiliation(s)
- Antony Citterio-Quentin
- UMR CNRS 5305, Clinical Pharmacy, Pharmacokinetics and Drug Evaluation, Université de Lyon, Université Lyon 1, Lyon, France.,Edouard Herriot Hospital, Laboratory of Medical Biology Multi Sites of the University Hospital of Lyon, Pharmaco-Toxicology Unit, Civil Hospices of Lyon, Lyon, France
| | - Mustapha Moulsma
- Edouard Herriot Hospital, Laboratory of Medical Biology Multi Sites of the University Hospital of Lyon, Pharmaco-Toxicology Unit, Civil Hospices of Lyon, Lyon, France
| | - Marie-Paule Gustin
- Emerging pathogen Laboratory - Fondation Mérieux, Centre International de Recherche en Infectiologie (CIRI), Inserm U1111, CNRS UMR5308, ENS de Lyon, UCBL1, Lyon, France
| | - Alain Lachaux
- Pediatric Gastroenterology Unit, Civil Hospices of Lyon, Hôpital Femme-Mère-Enfant (HFME), Lyon, France
| | - Roselyne Boulieu
- UMR CNRS 5305, Clinical Pharmacy, Pharmacokinetics and Drug Evaluation, Université de Lyon, Université Lyon 1, Lyon, France.,Edouard Herriot Hospital, Laboratory of Medical Biology Multi Sites of the University Hospital of Lyon, Pharmaco-Toxicology Unit, Civil Hospices of Lyon, Lyon, France
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12
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Kakuta Y, Kinouchi Y, Shimosegawa T. Pharmacogenetics of thiopurines for inflammatory bowel disease in East Asia: prospects for clinical application of NUDT15 genotyping. J Gastroenterol 2018; 53:172-180. [PMID: 29192347 PMCID: PMC5846876 DOI: 10.1007/s00535-017-1416-0] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Accepted: 11/19/2017] [Indexed: 02/06/2023]
Abstract
The thiopurine drugs 6-mercaptopurine (6-MP) and azathiopurine (AZA) are widely used to treat inflammatory bowel disease. However, the incidence of adverse reactions is high, particularly in Asia, and the mechanisms of toxicity in Asian populations remain unclear. Thiopurine S-methyltransferase (TPMT) is a well-known enzyme that inactivates AZA or 6-MP through methylation and is one of the few pharmacogenetic predictors used in clinical settings in Western countries. Individuals carrying TPMT-deficient genetic variants require reduced drug doses, but this treatment modification is are not applicable to East Asian populations. Several genes code thiopurine-metabolizing enzymes, including TPMT, multidrug-resistance protein 4, and inosine triphosphatase. These genes have been studied as candidate pharmacogenetic markers; however, it remains unclear why Asian populations seem to be more intolerant than other ethnic groups to a full dose of thiopurines. A genome-wide association approach to identify Asian-specific pharmacogenetic markers in Korean patients with Crohn's disease revealed that a non-synonymous single nucelotide polymorphism in nucleoside diphosphate-linked moiety X-type motif 15 (NUDT15) which causes p.Arg139Cys was strongly associated with thiopurine-induced early leukopenia. Six common haplotypes of NUDT15 were reported, and five variants showed medium-to-low enzyme activities, compared with the wild haplotype. NUDT15 hydrolyzes the thiopurine active metabolites 6-thio-GTP and 6-thio-dGTP; variants of NUDT15 had lower enzyme activities, causing higher levels of thiopurine active metabolites, resulting in thiopurine-induced leukopenia. In clinical application, NUDT15 genotyping is a good candidate for predicting thiopurine toxicity in East Asian populations. However, the association of NUDT15 diplotypes with thiopurine toxicity remains unclear. Further analyses with large cohorts to confirm the clinical effects of each haplotype are planned.
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Affiliation(s)
- Yoichi Kakuta
- Division of Gastroenterology, Tohoku University Graduate School of Medicine, 1-1 Seiryo, Aoba, Sendai, 980-8574 Japan
| | - Yoshitaka Kinouchi
- Institute for Excellent in Higher Education, Tohoku University, Sendai, Japan
| | - Tooru Shimosegawa
- Division of Gastroenterology, Tohoku University Graduate School of Medicine, 1-1 Seiryo, Aoba, Sendai, 980-8574 Japan
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13
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Abstract
Clinical trials for the most effective drugs in the armamentarium of medications for inflammatory bowel disease (IBD) have shown only a 50-60% response rate, and this drops to 30% in maintenance. However, therapeutic drug monitoring (TDM) to adjust dosing to account for patient-specific characteristics, which has been shown to improve outcomes, was not utilized in these trials. This review will detail the development of TDM within the IBD space as it evolved from thiopurines to biologics and continues to evolve with loftier treat-to-target goals and more sophisticated dashboard systems.
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Moreau B, Clement P, Theoret Y, Seidman EG. Allopurinol in combination with thiopurine induces mucosal healing and improves clinical and metabolic outcomes in IBD. Therap Adv Gastroenterol 2017; 10:819-827. [PMID: 29147133 PMCID: PMC5673019 DOI: 10.1177/1756283x17733657] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 06/15/2017] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Thiopurines, azathioprine (AZA) and 6-mercaptopurine (6-MP) are common maintenance medications for inflammatory bowel disease (IBD). Excessive methylation via thiopurine methyltransferase (TPMT) frequently causes therapeutic failure. Allopurinol reduces excessive 6-methyl-mercaptopurine (6-MMP) while enhancing 6-thioguanine (6-TGN) levels. The aim of this study was to evaluate clinical, metabolic and endoscopic impact of allopurinol in combination with low-dose thiopurine in IBD. METHODS Retrospective review of consecutive cases treated with allopurinol. Metabolites and their ratios (6-MMP/6-TGN) were compared pre- and post-allopurinol. Clinical and endoscopic remission were assessed. RESULTS Allopurinol (n = 66) reduced mean dose of AZA by 70% (p < 0.01). Baseline levels (SD) 6-TGN, 6-MMP and 6-MMP/6-TGN were 165 (64), 9388 (5234) and 59.8 (30.3), respectively. These values improved on allopurinol to 297 (102), 896 (1031) and 3.4 (4.0), respectively (p < 0.0001). Therapeutic 6-TGN level (>235) was achieved in 49/58 cases on allopurinol combination therapy, versus 9/58 monotherapy (p = 0.0001). Among the thiopurine failure group (40 patients), clinical remission or response was observed in 65% and 22% of patients, respectively. In the asymptomatic group with excessive 6-MMP, 11/14 achieved sustained remission on allopurinol. Repeat colonoscopy (n = 28) showed mostly endoscopic remission (67.9%) or improvement (17.8%). Few had unimproved lesions (14.3%). Importantly, 46% of cases had complete mucosal healing. Two patients had cancer on combination therapy (de novo pancreatic cancer and fatal recurrence of metastatic testicular cancer). Elevated transaminases were reduced on allopurinol (48.2 versus 6.9%) (p < 0.001); no change in leukopenic or infectious events occurred. CONCLUSION Allopurinol in combination with low-dose thiopurine corrected excessive 6-MMP levels, resulting in clinical remission and mucosal healing in the majority of cases. The potential cancer risk of allopurinol and thiopurine combination therapy needs further research.
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Affiliation(s)
- Brigitte Moreau
- Advanced IBD Fellow, Division of Gastroenterology, McGill University Health Center, Departments of Medicine and Pediatrics, Montreal, QC, Canada
| | - Pierre Clement
- Division of Gastroenterology, Gatineau Hospital, Gatineau, QC, Canada
| | - Yves Theoret
- Pharmacology Laboratory, Sainte Justine Hospital, Montreal, QC, Canada
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15
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Vögelin M, Biedermann L, Frei P, Vavricka SR, Scharl S, Zeitz J, Sulz MC, Fried M, Rogler G, Scharl M. The Impact of Azathioprine-Associated Lymphopenia on the Onset of Opportunistic Infections in Patients with Inflammatory Bowel Disease. PLoS One 2016; 11:e0155218. [PMID: 27214202 PMCID: PMC4877071 DOI: 10.1371/journal.pone.0155218] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 04/26/2016] [Indexed: 12/18/2022] Open
Abstract
Background Thiopurines are known to cause lymphopenia (<1,500 lymphocytes/μl). As severe lymphopenia (<500C/μl) is associated with opportunistic infections, we investigated severity of thiopurine-related lymphopenia and development of opportunistic infections in our tertiary referral centre. Methods We retrospectively screened medical records of 1,070 IBD patients and identified 100 individuals that developed a total of 161 episodes of lymphopenia during thiopurine treatment between 2002 and 2014. Occurrence of opportunistic infections was documented. A control group consisted of IBD patients receiving thiopurines but without developing lymphopenia. Results Of a total of 161 episodes of lymphopenia, 23% were severe (<500C/μl). In this subgroup, thiopurine dosing was modified in 64% (dosage reduction: 32%, medication discontinued: 32%). We identified 9 cases (5.5%) of opportunistic infections, of which only two occurred during severe lymphopenia. One opportunistic infection (4.5%) was identified in the control group. No association was found between opportunistic infections and severity of lymphopenia. All patients who suffered from opportunistic infections were receiving additional immunosuppressive medication. Conclusion Our patients treated with thiopurines rarely developed severe lymphopenia and opportunistic infections did not occur more often than in the control group. A careful monitoring of lymphocytes and prophylactic adjustment of thiopurine therapy might contribute to this low incidence.
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Affiliation(s)
- Marius Vögelin
- Division of Gastroenterology and Hepatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Luc Biedermann
- Division of Gastroenterology and Hepatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Pascal Frei
- Division of Gastroenterology and Hepatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Stephan R. Vavricka
- Division of Gastroenterology and Hepatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
- Division of Gastroenterology and Hepatology, Stadtspital Triemli, Zurich, Switzerland
- Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Sylvie Scharl
- Division of Gastroenterology and Hepatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Jonas Zeitz
- Division of Gastroenterology and Hepatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Michael C. Sulz
- Division of Gastroenterology and Hepatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
- Division of Gastroenterology and Hepatology, Kantonsspital St. Gallen, St. Gallen, Switzerland
| | - Michael Fried
- Division of Gastroenterology and Hepatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
- Division of Gastroenterology and Hepatology, Stadtspital Triemli, Zurich, Switzerland
| | - Gerhard Rogler
- Division of Gastroenterology and Hepatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
- Division of Gastroenterology and Hepatology, Stadtspital Triemli, Zurich, Switzerland
| | - Michael Scharl
- Division of Gastroenterology and Hepatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
- Division of Gastroenterology and Hepatology, Stadtspital Triemli, Zurich, Switzerland
- * E-mail:
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16
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Moon W, Loftus EV. Review article: recent advances in pharmacogenetics and pharmacokinetics for safe and effective thiopurine therapy in inflammatory bowel disease. Aliment Pharmacol Ther 2016; 43:863-883. [PMID: 26876431 DOI: 10.1111/apt.13559] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 08/26/2015] [Accepted: 01/26/2016] [Indexed: 12/16/2022]
Abstract
BACKGROUND Azathioprine and mercaptopurine have a pivotal role in the treatment of inflammatory bowel disease (IBD). However, because of their complex metabolism and potential toxicities, optimal use of biomarkers to predict adverse effects and therapeutic response is paramount. AIM To provide a comprehensive review focused on pharmacogenetics and pharmacokinetics for safe and effective thiopurine therapy in IBD. METHODS A literature search up to July 2015 was performed in PubMed using a combination of relevant MeSH terms. RESULTS Pre-treatment thiopurine S-methyltransferase typing plus measurement of 6-tioguanine nucleotides and 6-methylmercaptopurine ribonucleotides levels during treatment have emerged with key roles in facilitating safe and effective thiopurine therapy. Optimal use of these tools has been shown to reduce the risk of adverse effects by 3-7%, and to improve efficacy by 15-30%. For the introduction of aldehyde oxidase (AOX) into clinical practice, the association between AOX activity and AZA dose requirements should be positively confirmed. Inosine triphosphatase assessment associated with adverse effects also shows promise. Nucleoside diphosphate-linked moiety X-type motif 15 variants have been shown to predict myelotoxicity on thiopurines in East Asian patients. However, the impact of assessments of xanthine oxidase, glutathione S-transferase, hypoxanthine guanine phosphoribosyltransferase and inosine monophosphate dehydrogenase appears too low to favour incorporation into clinical practice. CONCLUSIONS Measurement of thiopurine-related enzymes and metabolites reduces the risk of adverse effects and improves efficacy, and should be considered part of standard management. However, this approach will not predict or avoid all adverse effects, and careful clinical and laboratory monitoring of patients receiving thiopurines remains essential.
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Affiliation(s)
- W Moon
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA.,Department of Internal Medicine, Kosin University College of Medicine, Busan, Korea
| | - E V Loftus
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
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17
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Abstract
PURPOSE OF REVIEW Drug-induced liver injury (DILI) is an underrecognized cause of pediatric liver disease, accounts for almost 20% of pediatric acute liver failure cases, and is a major reason for liver transplantation in the USA. This article reviews the pathogenesis of DILI, approach to diagnosis and management, and highlights recent pediatric DILI case series. RECENT FINDINGS Select individuals have an increased propensity to develop DILI. Known genetic polymorphisms of enzymes and host factors play an important role in medication management and influence the clinical outcome in 20-25% of all drug therapies. Children are more likely to have mitochondrial dysfunction from drugs, increasing their susceptibility to severe liver injury or acute liver failure. Antibiotics and central nervous system agents account for the majority of pediatric DILI in the West, although herbals are becoming more common. SUMMARY Clinical features of DILI vary and overlap so exclusion of other conditions, identification of latency period and risk factors, and use of a searchable database can aid evaluation. Treatment consists of cessation of the offending agent and supportive care. Areas needing further research include elucidating mechanisms, identifying at risk individuals, and therapeutic interventions.
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