| 1. |
- Pettersson, Jonas, et al.
(författare)
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Muscular exercise can cause highly pathological liver function tests in healthy men.
- 2008
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Ingår i: British Journal of Clinical Pharmacology. - : Wiley. - 1365-2125 .- 0306-5251. ; 65:2, s. 253-259
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Tidskriftsartikel (refereegranskat)abstract
- What is already known about this subject • The occurrence of idiosyncratic drug hepatotoxicity is a major problem in all phases of clinical drug development and the leading cause of postmarketing warnings and withdrawals. • Physical exercise can result in transient elevations of liver function tests. • There is no consensus in the literature on which forms of exercise may cause changes in liver function tests and to what extent. What this study adds • Weightlifting results in profound increases in liver function tests in healthy men used to moderate physical activity, not including weightlifting. • Liver function tests are significantly increased for at least 7 days after weightlifting. • It is important to impose relevant restrictions on heavy muscular exercise prior to and during clinical studies. Aim To investigate the effect of intensive muscular exercise (weightlifting) on clinical chemistry parameters reflecting liver function in healthy men. Methods Fifteen healthy men, used to moderate physical activity not including weightlifting, performed an 1 h long weightlifting programme. Blood was sampled for clinical chemistry parameters [aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LD), gamma-glutamyl transferase (γGT), alkaline phosphatase (ALP), bilirubin, creatine kinase (CK) and myoglobin] at repeated intervals during 7 days postexercise and at a follow-up examination 10–12 days postexercise. Results Five out of eight studied clinical chemistry parameters (AST, ALT, LD, CK and myoglobin) increased significantly after exercise (P < 0.01) and remained increased for at least 7 days postexercise. Bilirubin, γGT and ALP remained within the normal range. Conclusion The liver function parameters, AST and ALT, were significantly increased for at least 7 days after the exercise. In addition, LD and, in particular, CK and myoglobin showed highly elevated levels. These findings highlight the importance of imposing restrictions on weightlifting prior to and during clinical studies. Intensive muscular exercise, e.g. weightlifting, should also be considered as a cause of asymptomatic elevations of liver function tests in daily clinical practice.
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| 2. |
- Almer, Sven, et al.
(författare)
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6-Thioguanine therapy in Crohns disease-Observational data in Swedish patients
- 2009
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Ingår i: Digestive and Liver Disease. - : Elsevier BV. - 1590-8658 .- 1878-3562. ; 41:3, s. 194-200
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Tidskriftsartikel (refereegranskat)abstract
- Background and aims: Adverse events (AE) leading to discontinuation or dose-reduction of thiopurine therapy (TP) occur in 9-28% of patients with inflammatory bowel disease. 6-Thioguanine (6-TG) has been proposed as an alternative treatment in patients intolerant for azathioprine (AZA), but some concerns have been raised about drug safety. Methods: We evaluated in a prospective manner the tolerance and efficacy of 6-TG in 23 Crohns disease (CD) patients (13 men, median age 41 (19-65) years) with prior intolerance (n = 18) or resistance (It = 5) to AZA and/or 6-mercaptopurine (6-MP). In addition, eight patients had tried mycophenolate mofetil. Seventeen patients (74%) had undergone intestinal resection, often several times. Results: Patients were treated with a median daily dose of 40 mg 6-TG (range 20-60) for 259 (15-2272) days. Seven of 13 patients (54%) with active disease went into remission after 8 (4-26) weeks. Sixteen patients (70%) experienced AE that lead to discontinuation (n=10) after 85 (15-451) days or dose reduction (n=6) after 78 (10-853) days. Ten of 18 patients (56%) with prior TP-intolerance discontinued 6-TG treatment due to AE compared to none of five patients with TP-resistance (p=0.046). Of 13 patients that tolerated 6-TG, eight discontinued the drug due to therapeutic failure (n=5) or safety concerns (n=3). Eight patients (35%) continued treatment beyond 12 months. There was no significant difference in maximum thioguanine nucleotide levels between patients with AE leading to discontinuation/dose reduction and patients without AE, 652 (99-2488) vs. 551 (392-1574) pmol/8 x 10(8) RBC; p=0.80. Conclusions: In this cohort of CD patients with severe disease failing traditional thiopurine treatment, a small fraction (22%) had long-term benefit of 6-TG-treatment. 6-TG therapy seems to offer a limited therapeutic gain for patients intolerant to both AZA and 6-MP and other treatment options should be considered.
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| 3. |
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| 4. |
- Angelison, Leif, et al.
(författare)
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Short and long-term efficacy of adalimumab in ulcerative colitis : a real-life study
- 2020
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Ingår i: Scandinavian Journal of Gastroenterology. - : Informa UK Limited. - 0036-5521 .- 1502-7708. ; 55:2, s. 154-162
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Randomized controlled trials have shown the effectiveness of Adalimumab in ulcerative colitis. However, real-life data is scarce. We aimed to assess the effectiveness and predictive factors of effectiveness in a large Swedish cohort. Methods: Retrospective capture of data from local registries at five Swedish IBD centers. Clinical response and remission rates were assessed at three months after starting adalimumab treatment and patients were followed until colectomy or need for another biological. Bio-naive patients were compared to bio experienced patients. Factors associated with short term responses were assessed using logistic regression model. Failure on drug was assessed using a Cox proportional hazards regression model. Results: 118 patients (59 males, 59 females) with median age 34.4 years (IQR 27.0–51.4) were included. Median disease duration was 4.3 years (IQR 2.0–9.0) and follow-up 1.27 years (IQR 0.33–4.1). A clinical corticosteroid-free remission was achieved by 38/118 (32.2%) and response by 91/118 (77%) after three months. CRP >3 mg/l at baseline was predictive of short-term failure to reach corticosteroid-free remission. Factors associated with survival on the drug were male gender, CRP <3 mg/l and absence of primary sclerosing cholangitis. Patients >42 years of age at diagnosis were more likely to respond to adalimumab and remain on treatment compared to patients <20 years. Conclusions: An elevated CRP-level, primary sclerosing cholangitis and female gender were predictors of treatment failure. In contrast older age at diagnosis was a predictor of short-term clinical response and drug survival. Prior infliximab failure, regardless of cause, did not influence the outcome of adalimumab treatment.
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| 5. |
- Duan, Rui-Dong, et al.
(författare)
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Changes of activity and isoforms of alkaline sphingomyelinase (nucleotide pyrophosphatase phosphodiesterase 7) in bile from patients undergoing endoscopic retrograde cholangiopancreatography.
- 2014
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Ingår i: BMC Gastroenterology. - 1471-230X. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Alkaline sphingomyelinase (NPP7) is an ecto-enzyme expressed in intestinal mucosa, which hydrolyses sphingomyelin (SM) to ceramide and inactivates platelet activating factor. It is also expressed in human liver and released in the bile. The enzyme may have anti-tumour and anti-inflammatory effects in colon and its levels are decreased in patients with colon cancer and ulcerative colitis. Active NPP7 is translated from a transcript of 1.4 kb, whereas an inactive form from a 1.2 kb mRNA was found in colon and liver cancer cell lines. While the roles of NPP7 in colon cancer have been intensively studied, less is known about the function and implications of NPP7 in the bile. The present study examines the changes of NPP7 in bile of patients with various hepatobiliary diseases.
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| 6. |
- Fransson, Martin, 1978-, et al.
(författare)
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A preliminary study of modeling and simulation in individualized drug dosage – azathioprine on inflammatory bowel disease
- 2007
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Ingår i: SIMS 2006: Proceedings of the 47th Conference on Simulation and Modelling, Helsinki, Finland. - Helsinki : Kopio Niini Oy. - 9525183300 ; , s. 216-220
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Konferensbidrag (refereegranskat)abstract
- Individualized drug dosage based on population pharmacokinetic/dynamic models is an important future technology used to reduce or eliminate side effects of certain drugs, e.g. cancer drugs. In this paper we report preliminary results from work-in-progress: a simplified linear model of the metabolism of a cancer treatment drug was estimated from experimental data. The model was then validated against the same data as a test of the adequacy of the model structure. From this investigation it became apparent that the model structure could not be used due to its inability to recreate the dynamic properties of the system.
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| 7. |
- Haglund, Sofie, et al.
(författare)
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The Role of Inosine-5'-Monophosphate Dehydrogenase in Thiopurine Metabolism in Patients With Inflammatory Bowel Disease.
- 2011
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Ingår i: Therapeutic Drug Monitoring. - : Lippincott Williams & Wilkins. - 0163-4356 .- 1536-3694. ; 33:2, s. 200-208
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND:: There is a large interindividual variability in thiopurine metabolism. High concentrations of methylthioinosine-5'-monophosphate (meTIMP) and low concentrations of 6-thioguanine nucleotides (6-TGNs) have been associated with a lower response rate and an increased risk of adverse events. In this study, the role of inosine-5'-monophosphate dehydrogenase (IMPDH) for differences in metabolite patterns of thiopurines was investigated. METHODS:: IMPDH activity and thiopurine metabolite concentrations were determined in patients with inflammatory bowel disease and a normal thiopurine methyltransferase (TPMT) phenotype and meTIMP/6-TGN concentration ratio > 20 (n = 26), in patients with a metabolite ratio ≤20 (n = 21), in a subgroup with a metabolite ratio <4 (n = 6), and in 10 patients with reduced TPMT activity. In vitro studies were conducted on human embryonic kidney cells (HEK293) with genetically engineered IMPDH and TPMT activities. RESULTS:: Patients with metabolite ratios >20 had lower IMPDH activity than those with ratios ≤20 (P < 0.001). Metabolic ratios >20 were only observed in patients with normal TPMT activity. Downregulation of IMPDH activity in HEK293 cells was associated with an increase in the concentration of meTIMP (fold change: 17 up to 93, P < 0.001) but, unexpectedly, also of 6-thioguanosine monophosphate (fold change: 2.6 up to 5.0, P < 0.001). CONCLUSIONS:: These data question the general view of IMPDH as the rate-limiting enzyme in the phosphorylation of thiopurines. Investigations of other mechanisms are needed to more fully explain the various metabolite patterns and outcomes in patients under treatment.
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| 8. |
- Henriksson, Gunnel, et al.
(författare)
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Humoral response to Clostridium difficile in inflammatory bowel disease, including correlation with immunomodulatory treatment
- 2019
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Ingår i: JGH Open. - : Wiley. - 2397-9070. ; 3:2, s. 154-158
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Tidskriftsartikel (refereegranskat)abstract
- Background and Aim: An abnormal immune response to intestinal bacteria has been observed in Crohn's disease (CD). Clostridium difficile infection incidence and severity are increased in CD, but reports on the humoral response have provided conflicting results. We aimed to shed light on the possible role of C. difficile in CD pathogenesis by paying attention to the influence of immunomodulatory treatment on the humoral response.Methods: A total of 71 consecutive outpatients with CD, 67 with ulcerative colitis (UC), and 121 healthy controls were analyzed for serum IgA and IgG to C. difficile toxins A and B.Results: IgA levels were similar in all study groups. IgG to toxin A was increased similarly in CD and UC (P = 0.02 for both). In contrast, IgG to toxin B was elevated only in CD patients not receiving disease-modifying anti-inflammatory bowel disease drugs (DMAID) (n = 16) (P = 0.0001), while the CD medication subgroup (n = 47) had a level similar to healthy controls. The UC results were not influenced by DMAID treatment.Conclusion: Our findings add support to the idea of a disturbed interaction between intestinal cells and the microbiota being part of the CD disease mechanism. An abnormal immune response to C. difficile toxin B may be a critical component of this interaction.
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| 9. |
- Hindorf, Ulf, et al.
(författare)
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Adverse events leading to modification of therapy in a large cohort of patients with inflammatory bowel disease
- 2006
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Ingår i: Alimentary Pharmacology and Therapeutics. - : Wiley. - 0269-2813 .- 1365-2036. ; 24:2, s. 331-342
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Tidskriftsartikel (refereegranskat)abstract
- Background: Adverse events leading to discontinuation or dose reduction of thiopurine therapy occur in 9-28% of patients with inflammatory bowel disease. Aims: To evaluate the influence of thiopurine methyltransferase status and thiopurine metabolites in a large patient population for the risk of developing adverse event. Methods: Three hundred and sixty-four patients with inflammatory bowel disease and present or previous thiopurine therapy were identified from a local database. Results: The adverse event observed in 124 patients (34%) were more common in adults than children (40% vs. 15%, P < 0.001) and in low to intermediate (≤9.0 U/mL red blood cell) than normal thiopurine methyltransferase activity (P = 0.02). Myelotoxicity developed later than other types of adverse event. An increased frequency of adverse event was observed in patients with tioguanine (thioguanine) nucleotide above 400 or methylated thioinosine monophosphate above 11 450 pmol/ 8 × 108 red blood cell. A shift to mercaptopurine was successful in 48% of azathioprine-intolerant patients and in all cases of azathioprine-induced myalgia or arthralgia. Conclusions: A pre-treatment determination of thiopurine methyltransferase status might be appropriate as patients with low to intermediate thiopurine methyltransferase activity are more prone to develop an adverse event, determination of metabolite levels can be useful in the case of an adverse event. Mercaptopurine therapy should be considered in azathioprine-intolerant patients. © 2006 The Authors.
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| 10. |
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| 11. |
- Hindorf, Ulf, et al.
(författare)
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Characterisation and utility of thiopurine methyltransferase and thiopurine metabolite measurements in autoimmune hepatitis.
- 2010
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Ingår i: Journal of Hepatology. - : Elsevier BV. - 0168-8278 .- 1600-0641. ; 52:1, s. 106-111
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND & AIMS: Corticosteroids alone or in conjunction with azathioprine (AZA) is the standard treatment in autoimmune hepatitis (AiH). Individual variations in thiopurine (TP) metabolism may affect both drug efficacy and toxicity. Our aim was to investigate the utility of thiopurine methyltransferase (TPMT) as well as thioguanine nucleotide (TGN) and methylthioinosine monophosphate (meTIMP) metabolite measurements with regard to clinical outcome. METHODS: Two hundred thirty-eight patients with AiH were included in this cross-sectional study. TPMT status was assessed in all patients, while TGN and meTIMP were measured in patients with ongoing TP medication. Clinical outcome was evaluated by liver tests and the ability to withdraw steroids. RESULTS: TPMT genotyping (n=229) revealed 207 (90.4%) wild-type and 22 heterozygous patients. One hundred forty-three patients had ongoing TP therapy with AZA (n=134) or mercaptopurine (MP; n=9); response was judged as complete response (CR) in 113 patients and partial response (PR) in 30 patients. Both TP dose (1.64 vs 1.19mg/kg; p=0.012) and TPMT activity (14.3 vs 13.5; p=0.05) were higher in PR, resulting in similar TGN levels (PR: 121pmol/8x10(8) red blood cells [RBC]; CR: 113pmol/8x10(8) RBC; p=0.33) but higher meTIMP levels in PR (1350 vs 400pmol/8x10(8) RBC; p=0.004). Patients able to withdraw steroids or who were using 5mg prednisolone daily were treated with lower TP doses than patients on higher steroid doses (1.15 vs 1.18 vs 1.82mg/kg; p<0.001). CONCLUSIONS: TP metabolite measurements are of clinical value in AiH patients who do not respond to standard TP treatment and for the identification of a shifted metabolism, which may demand an alternative treatment strategy.
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| 12. |
- Hindorf, Ulf
(författare)
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Clinical studies of thiopurine metabolism in inflammatory bowel disease.
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Inflammatory bowel disease (IBD, i.e. primarily Crohn's disease and ulcerative colitis) is characterised by a chronic or relapsing inflammation of the digestive tract. The thiopurine drugs 6-mercaptopurine (6-MP) and azathioprine (AZA, an imidazol derivative and pro-drug of 6-MP) are currently used to an increased extent in IBD, particularly in Crohn's disease. Metabolism of thiopurines is complex and individually variable. Thus, the formation of biologically active thioguanine nucleotides (TGN) and methylated metabolites may vary considerably. Thiopurine methyltrasferase (TPMT) is a key enzyme in this metabolism and exhibits a genetic variability due to a number of variant alleles coding for an inactive enzyme when occurring in the homozygous form. Postulating that pharmacological monitoring and TPMT determinations may improve clinical efficacy and reduce side effects of thiopurine therapy we examined TMPT variation and metabolite levels in relation to clinical findings in patients with IBD. TPMT status was of clinical importance in the toxicity observed during thiopurine therapy. Patients with decreased TPMT activity were more prone to develop adverse events and less likely to tolerate a standard thiopurine dose due to toxicity. The formation of metabolites after dose escalation was influenced by TPMT status. Subjects with normal TPMT activity shifted the metabolism towards production of methylated metabolites, while subjects with intermediate TPMT activity exhibit pronounced elevations of TGN metabolites even with small dose escalations. There was no general induction of TPMT activity after standardized initiation of thiopurine therapy. We found no correlation between AZA dose and TGN levels in two independent patient populations, but there was a linear relationship between AZA dose and methylated metabolites. The level of TGN metabolites were related to disease activity, with higher levels in disease remission. It is thus clinically useful to monitor TGN metabolites as an evaluation of treatment intensity. The total number of adverse events was higher in patients both with high TGN and high meTIMP metabolite concentrations and high levels of methylated metabolites (meTIMP) were associated with the development of myelotoxicity. In conclusion, these results suggest that TPMT activity measurements and pharmacological monitoring of thiopurine metabolites are useful in the clinical setting.
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| 13. |
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| 14. |
- Hindorf, Ulf, et al.
(författare)
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Genotyping should be considered the primary choice for pre-treatment evaluation of thiopurine methyltransferase function
- 2012
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Ingår i: Journal of Crohn's and Colitis. - : Elsevier. - 1873-9946. ; 6:6, s. 655-659
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Tidskriftsartikel (refereegranskat)abstract
- Background and aimsA pre-treatment determination of the thiopurine S-methyltransferase (TPMT) genotype or phenotype can identify patients at risk of developing severe adverse reactions from thiopurine treatment. The risk of misclassifying a patient might be dependent on the method used. The aim of this study was to investigate the concordance between TPMT genotyping and phenotyping.MethodsThe data consist of 7195 unselected and consecutive TPMT genotype and phenotype determinations sent to the division of Clinical Pharmacology, Linköping, Sweden. TPMT activity was measured in red blood cells (RBC) and the genotype determined by pyrosequencing for the three most common TPMT variants (TPMT *2, *3A, *3C).ResultsTPMT genotyping identified 89% as TPMT wild type (*1/*1), 10% as TPMT heterozygous and 0.5% as TMPT defective. The overall concordance between genotyping and phenotyping was 95%, while it was 96% among IBD patients (n = 4024). Genotyping would have misclassified 8% of the TPMT defectives as heterozygous as compared to 11% if only TPMT activity had been measured. 11% of the heterozygous patients had a normal TPMT activity (> 8.9 U/ml RBC) and 3% of the TPMT wild-type patients had an intermediate TPMT activity (2.5–8.9 U/ml RBC).ConclusionsThere is a risk for TPMT misclassification when only genotyping or phenotyping is used, but it is not reasonable to check both in all patients. Since TPMT genotyping is the more reliable test, especially in TPMT heterozygotes, we suggest that genotyping should be considered the primary choice for the pre-treatment evaluation of TPMT function before initiation of thiopurine therapy.
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| 15. |
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| 16. |
- Hindorf, Ulf, et al.
(författare)
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How are thiopurines used and monitored by Swedish gastroenterologists when treating patients with inflammatory bowel disease?
- 2011
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Ingår i: Scandinavian Journal of Gastroenterology. - : Informa UK Limited. - 1502-7708 .- 0036-5521. ; 46, s. 1215-1221
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Tidskriftsartikel (refereegranskat)abstract
- Objective. To perform a survey of thiopurine treatment in inflammatory bowel disease (IBD) among Swedish gastroenterologists. Material and methods. A web-based questionnaire consisting of 25 multiple-choice questions was sent to 322 gastroenterologists in adult practice. Results. A total of 132 questionnaires were received giving a response rate of 41%. Thiopurines were used by all 122 gastroenterologists in IBD practice and azathioprine was the first-choice thiopurine among 118 (97%) of them. Almost all gastroenterologists (97%) used weight-based dosing that was gradually escalated. The vast majority (89%) considered that efficacy should be evaluated within 6 months of therapy, while opinions regarding the optimal duration of therapy varied considerably. It was seen that 74% switched thiopurine in case of intolerance to the first-line substance. Thiopurine S-methyltransferase (TPMT) determinations were performed by 74% of the gastroenterologists and 67% used metabolite measurements. TPMT analyzers were more likely to measure metabolites (74 vs. 43%, p = 0.002). A quarter of the respondents were familiar with unconventional immunomodulation (co-administration of allopurinol, 6-thioguanine, mycophenolate mofetil or tacrolimus) and these respondents were also more likely to measure metabolites (79 vs. 52%; p = 0.002). Conclusions. Thiopurines are well established in the treatment of IBD among Swedish gastroenterologists. New and evolving knowledge about thiopurine therapy in IBD has been adapted to a large extent. Whether this change in clinical practice will have an impact on treatment outcomes has yet to be proven.
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| 17. |
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| 18. |
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| 19. |
- Hindorf, Ulf, et al.
(författare)
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Mercaptopurine treatment should be considered in azathioprine intolerant patients with inflammatory bowel disease
- 2009
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Ingår i: Alimentary Pharmacology & Therapeutics. - : Wiley. - 1365-2036 .- 0269-2813. ; 29:6, s. 654-61
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Adverse drug reactions are a significant reason for therapeutic failure during thiopurine treatment of inflammatory bowel disease. Some smaller series in this patient population have shown that a switch to mercaptopurine may be successful in many cases of azathioprine intolerance. AIM: To assess the long-term outcome of mercaptopurine treatment in a large patient population with azathioprine intolerance. METHODS: We identified 135 patients (74 women; median age 40 years) with Crohn's disease (n = 88) or ulcerative colitis (n = 47) and reviewed their medical records. RESULTS: A total of 70 patients (52%) tolerated mercaptopurine and were followed up for 736 (362-1080) days; 65 patients discontinued mercaptopurine due to adverse events after 25 (8-92) days. Mercaptopurine was tolerated in 71% (12/17) with hepatotoxicity and in 68% (13/19) with arthralgia/myalgia during azathioprine treatment. Previous abdominal surgery was more common in mercaptopurine intolerant patients [39/65 (60%) vs. 27/70 (39%); P = 0.02] and thiopurine methyltransferase activity was higher in mercaptopurine tolerant patients than in mercaptopurine intolerant patients [13.2 (11.4-15.3) vs. 11.8 (9.6-14.2) U/mL red blood cells; P = 0.04; n = 81]. CONCLUSIONS: A trial of mercaptopurine should be considered in azathioprine intolerance, as half of the patients tolerate a switch to mercaptopurine. Patients with hepatotoxicity or arthralgia/myalgia during azathioprine treatment might benefit more often than those with other types of adverse events.
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| 20. |
- Hindorf, Ulf, et al.
(författare)
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Monitoring of long-term thiopurine therapy among adults with inflammatory bowel disease
- 2004
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Ingår i: Scandinavian Journal of Gastroenterology. - : Informa UK Limited. - 1502-7708 .- 0036-5521. ; 39:11, s. 1105-1112
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Tidskriftsartikel (refereegranskat)abstract
- Background: The immunosuppressive effects of thiopurine drugs are mainly mediated through their intracellular metabolism into active 6-thioguanine nucleotide (6-TGN) metabolites, which are incorporated into DNA. Erythrocyte 6-TGN (E-6TGN) levels have been proposed as an instrument for monitoring treatment. The aim of the study was to use erythrocyte E-6TGN, methylated mercaptopurine (MeMP) metabolites, and thiopurine methyltransferase (TPMT) measurements in a clinical setting to determine the clinical outcome in relation to thiopurine metabolism. Methods: Fifty-five adult patients with inflammatory bowel disease were included in a prospective study and followed for 6 months. Metabolite levels were measured and correlated to outcome and AZA/6-MP dose. Results: The E-6TGN level was significantly related to the TPMT genotype ( P = 0.008). Patients in disease remission had higher E-6TGN levels than patients with disease activity both at baseline ( P < 0.05) and after 6 months ( P = 0.02). Active disease was more frequent among subjects with E-6TGN &LE; 125 nmol/mmol Hb at baseline ( P = 0.04), but not at 6 months. AZA/6-MP drug dose was positively correlated to E-MeMP levels (r(s) = 0.48; P < 0.001) and E-MeMP/E-6TGN ratio (r(s) = 0.41; P = 0.002). Dose changes were positively correlated with the changes in E-MeMP levels ( P = 0.01) and E-MeMP/E-6TGN ratio (P = 0.03). Conclusions: E-6TGN level was the only factor in this study related to disease activity, while there was no relationship between AZA/6-MP dose and E-6TGN levels. This finding illustrates the clinical usefulness of E-6TGN monitoring in the evaluation of treatment intensity.
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| 21. |
- Hindorf, Ulf, et al.
(författare)
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Pharmacogenetics during standardised initiation of thiopurine therapy in inflammatory bowel disease.
- 2006
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Ingår i: Gut. - : BMJ. - 1468-3288 .- 0017-5749. ; 55:10, s. 1423-1431
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Tidskriftsartikel (refereegranskat)abstract
- Background: Firm recommendations about the way thiopurine drugs are introduced and the use of thiopurine methyltransferase (TPMT) and metabolite measurements during treatment in inflammatory bowel disease (IBD) are lacking. Aim: To evaluate pharmacokinetics and tolerance after initiation of thiopurine treatment with a fixed dosing schedule in patients with IBD. Patients: 60 consecutive patients with Crohn's disease (n = 33) or ulcerative colitis (n = 27) were included in a 20 week open, prospective study. Methods: Thiopurine treatment was introduced using a predefined dose escalation schedule, reaching a daily target dose at week 3 of 2.5 mg azathioprine or 1.25 mg 6-mercaptopurine per kg body weight. TPMT and ITPA genotypes, TPMT activity, TPMT gene expression, and thiopurine metabolites were determined. Clinical outcome and occurrence of adverse events were monitored. Results: 27 patients completed the study per protocol, while 33 were withdrawn (early protocol violation (n = 5), TPMT deficiency (n = 1), thiopurine related adverse events (n = 27)); 67% of patients with adverse events tolerated long term treatment on a lower dose (median 1.32 mg azathioprine/kg body weight). TPMT activity did not change during the 20 week course of the study but a significant decrease in TPMT gene expression was found (TPMT/huCYC ratio; p = 0.02). Patients with meTIMP concentrations > 11 450 pmol/8 x 10(8) red blood cells during steady state at week 5 had an increased risk of developing myelotoxicity (odds ratio = 45.0; p = 0.015). Conclusions: After initiation of thiopurine treatment using a fixed dosing schedule, no general induction of TPMT enzyme activity occurred, though TPMT gene expression decreased. The development of different types of toxicity was unpredictable, but we found that measurement of meTIMP early in the steady state phase helped to identify patients at risk of developing myelotoxicity.
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| 22. |
- Hindorf, Ulf, et al.
(författare)
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Pharmacogenetics during standardised initiation of thiopurine treatment in inflammatory bowel disease
- 2006
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Ingår i: Gut. - : BMJ. - 0017-5749 .- 1468-3288. ; 55:10, s. 1423-1431
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Tidskriftsartikel (refereegranskat)abstract
- Background: Firm recommendations about the way thiopurine drugs are introduced and the use of thiopurine methyltransferase (TPMT) and metabolite measurements during treatment in inflammatory bowel disease (IBD) are lacking. Aim: To evaluate pharmacokinetics and tolerance after initiation of thiopurine treatment with a fixed dosing schedule in patients with IBD. Patients: 60 consecutive patients with Crohn's disease (n = 33) or ulcerative colitis (n = 27) were included in a 20 week open, prospective study. Methods: Thiopurine treatment was introduced using a predefined dose escalation schedule, reaching a daily target dose at week 3 of 2.5 mg azathioprine or 1.25 mg 6-mercaptopurine per kg body weight. TPMT and ITPA genotypes, TPMT activity, TPMT gene expression, and thiopurine metabolites were determined. Clinical outcome and occurrence of adverse events were monitored. Results: 27 patients completed the study per protocol, while 33 were withdrawn (early protocol violation (n = 5), TPMT deficiency (n = 1), thiopurine related adverse events (n = 27)), 67% of patients with adverse events tolerated long term treatment on a lower dose (median 1.32 mg azathioprine/kg body weight). TPMT activity did not change during the 20 week course of the study but a significant decrease in TPMT gene expression was found (TPMT/huCYC ratio, p = 0.02). Patients with meTIMP concentrations > 11 450 pmol/8 × 108 red blood cells during steady state at week 5 had an increased risk of developing myelotoxicity (odds ratio = 45.0, p = 0.015). Conclusions: After initiation of thiopurine treatment using a fixed dosing schedule, no general induction of TPMT enzyme activity occurred, though TPMT gene expression decreased. The development of different types of toxicity was unpredictable, but we found that measurement of meTIMP early in the steady state phase helped to identify patients at risk of developing myelotoxicity.
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| 23. |
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| 24. |
- Lindqvist Appell, Malin, et al.
(författare)
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A skewed thiopurine metabolism is a common clinical phenomenon that can be successfully managed with a combination of low-dose azathioprine and allopurinol
- 2013
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Ingår i: Journal of Crohn's & Colitis. - : Elsevier. - 1873-9946 .- 1876-4479. ; 7:6, s. 510-513
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Tidskriftsartikel (refereegranskat)abstract
- Background and aims: A skewed thiopurine metabolism is a phenomenon associated with both poor treatment response and toxicity. Our aim was to evaluate the frequency of this phenomenon and the relationship to thiopurine methyltransferase (TPMT) function. less thanbrgreater than less thanbrgreater thanMethods: All thiopurine metabolite measurements in adult patients (n=4033) between January 2006 and April 2012 were assessed to evaluate the occurrence of a skewed metabolism and the relationship to TPMT genotype and activity. less thanbrgreater than less thanbrgreater thanResults: A skewed metabolism was observed in 14% of all patients. It only developed in patients with a normal TPMT genotype, but was observed at all TPMT activity levels within the normal range (9.1-24.2 U/ml RBC). Two cases that illustrate typical clinical scenarios of a skewed metabolism and the effect of combination treatment with low-dose azathioprine and allopurinol are presented. less thanbrgreater than less thanbrgreater thanConclusions: A skewed metabolism is a common clinical phenomenon in patients with a normal TPMT function, which can develop at all TPMT activity levels within the normal range. We suggest that metabolite measurements should be considered in patients not responding to treatment and in those with hepatotoxicity or myelotoxicity in order to detect a skewed metabolism, since this phenomenon can be successfully managed by a combination of low-dose azathioprine and allopurinol.
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| 25. |
- Lindqvist Appell, Malin, 1976-, et al.
(författare)
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No induction of thiopurine methyltransferase during thiopurine treatment in inflammatory bowel disease
- 2006
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Ingår i: Nucleosides, Nucleotides & Nucleic Acids. - : Informa UK Limited. - 1525-7770 .- 1532-2335. ; 25:9-11, s. 1033-1037
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to follow, during standardized initiation of thiopurine treatment, thiopurine methyltransferase (TPMT) gene expression and enzyme activity and thiopurine metabolite concentrations, and to study the role of TPMT and ITPA 94C > A polymorphisms for the development of adverse drug reactions. Sixty patients with ulcerative colitis or Crohn's disease were included in this open and prospective multi-center study. Thiopurine naive patients were prescribed azathioprine (AZA), patients previously intolerant to AZA received 6-mercaptopurine (6-MP). The patients followed a predetermined dose escalation schedule, reaching target dose at Week 3; 2.5 and 1.25 mg/kg body weight for AZA and 6-MP, respectively. The patients were followed every week during Weeks 1-8 from baseline and then every 4 weeks until 20 weeks. TPMT activity and thiopurine metabolites were determined in erythrocytes, TPMT and ITPA genotypes, and TPMT gene expression were determined in whole blood. One homozygous TPMT-deficient patient was excluded. Five non compliant patients were withdrawn during the first weeks. Twenty-seven patients completed the study per protocol; 27 patients were withdrawn because of adverse events. Sixty-seven percent of the withdrawn patients tolerated thiopurines at a lower dose at Week 20. There was no difference in baseline TPMT enzyme activity between individuals completing the study and those withdrawn for adverse events (p = 0.45). A significant decrease in TPMT gene expression (TPMT/huCYC ratio, p = 0.02) was found, however TPMT enzyme activity did not change. TPMT heterozygous individuals had a lower probability of remaining in the study on the predetermined dose (p = 0.039). The ITPA 94C > A polymorphism was not predictive of adverse events (p = 0.35).
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| 26. |
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| 27. |
- Lindqvist Appell, Malin, 1976-, et al.
(författare)
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Thiopurines in inflammatory bowel disease - The role of pharmacogenetics and therapeutic drug monitoring
- 2006
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Ingår i: Current Pharmacogenomics. - : Bentham Science Publishers Ltd.. - 1570-1603. ; 4:4, s. 285-300
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Tidskriftsartikel (refereegranskat)abstract
- Pharmacogenetics represents the study of variability in drug response due to genetic variations. Inflammatory bowel disease (IBD, i.e. primarily Crohn's disease and ulcerative colitis) is characterized by a chronic or relapsing inflammation of the digestive tract. The thiopurines 6-mercaptopurine (6-MP) and azathioprine (AZA), an imidazol derivative and pro-drug of 6-MP, are widely used in IBD, particularly in Crohn's disease. The metabolism of thiopurines is complex and individually variable. Thiopurine methyltransferase (TPMT) is a key enzyme in this metabolism and exhibits a genetic variability due to a number of variant alleles coding for a defective enzyme. The formation of biologically active thioguanine nucleotides (TGN) and methylated metabolites may vary considerably due to the TPMT activity. Patients with decreased TPMT activity are at increased risk of developing severe side effects if treated with conventional thiopurine doses, due to the accumulation of toxic metabolites. Determination of the TPMT phenotype or genotype is often used to identify individuals with increased risk for adverse events. Twenty-one variant TPMT alleles have been described, of which three are more common than the others. An association between inosine triphosphate pyrophosphatase polymorphisms and adverse events during thiopurine treatment has also been proposed. In this review, the clinical value of TPMT status determination and pharmacological monitoring of thiopurine metabolites are discussed as well as the increased interest in the use of 6-thioguanine, a thiopurine with a less complex metabolism, as an alternative for patients who do not tolerate AZA or 6-MP. It can be concluded that TPMT determination before start of thiopurine therapy is of value to identify individuals with increased risk for adverse reactions due to genetic enzyme deficiency. However, large prospective studies are still needed to evaluate the true benefit of monitoring thiopurine metabolites during thiopurine treatment. © 2006 Bentham Science Publishers Ltd.
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| 28. |
- Vikingsson, Svante, et al.
(författare)
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Novel assay to improve therapeutic drug monitoring of thiopurines in inflammatory bowel disease
- 2014
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Ingår i: Journal of Crohn's & Colitis. - : Elsevier. - 1873-9946 .- 1876-4479. ; 8:12, s. 1702-1709
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Tidskriftsartikel (refereegranskat)abstract
- Background and aims: The thiopurines are widely used in the treatment of inflammatory bowel disease, but are limited by poor dose effect relationship. The objective was to assess the ability of a novel assay, determining the mono-, di-, and triphosphates, of thioguanine as well as methylthioinosine as individual metabolites in erythrocytes, to predict clinical outcome compared to a routine assay, determining metabolites as sums. Methods: Samples from 79 patients with Crohns disease or ulcerative colitis treated with azathioprine or mercaptopurine were analysed by both assays. Clinical status was determined by the Harvey-Bradshaw and Walmsley indices. The genotypes of thiopurine methyltransferase (TPMT) and inosine triphosphatase were determined. Results: TPMT wild-type patients with thioguanine nucleotide (TGN) levels below the cut-off level were more likely to have active disease when TGN was measured by the novel assay (p = 0.02), and when thioguanosine triphosphate (TGTP) was measured separately (p = 0.01). When TGN was measured by the routine assay the correlation was not evident (p = 0.12). Neither TGN levels nor TGTP correlated to disease activity in TPMT deficient patients. Patients with methyl thioinosine nucleotide (meTIN) levels above 1500 pmol/8 x 10less than^greater than8 RBCs were more likely to have active disease (p = 0.07). We observed good correlations between the mono-, di-, and triphosphates and their respective sums (R-2 greater than 0.88). Conclusions: The novel TGN assay was better in predicting clinical outcome compared to the routine assay, while determination of TGTP had no clinical advantage and TGTP ratio was not correlated to disease activity. (C) 2014 European Crohns and Colitis Organisation. Published by Elsevier B.V. All rights reserved.
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| 29. |
- Vikingsson, Svante, et al.
(författare)
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Therapeutic drug monitoring of thiopurines in inflammatory bowel disease : Evaluating the benefit of measuring mono-, di-, and triphosphates separately
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The thiopurines are widely used in the treatment of inflammatory bowel diseases but are limited by poor dose-effect relationship and large interindividual variability in clinical effects. Many attempts have been made to predict response by therapeutic drug monitoring of phosphorylated and methylated metabolites grouped together as thioguanine nucleotides and methylthioinosine monophosphate. We have developed a method to determine the individual metabolites, thioguanosine mono-, di-, and triphosphates, as well as methylthioinosine mono-, di-, and triphosphates, separately in red blood cells.This aim of this study was to assess the ability of our novel method to predict clinical outcome compared to the routine method in 82 patients with inflammatory bowel diseases.TPMT wild-type patients with TGN levels below the cut-off level were more likely to have an active disease when TGN was measured by both the routine method (p < 0.05), the novel method (p<0.05), and when TGTP was measured separately (p < 0.01). TGN levels and TGTP were, however, not correlated to disease activity in TPMT defective patients. Patients with meTIN levels above 1500 pmol were more likely to have an active disease (39%, 18/46 vs. 17%, 5/30; p = 0.02). We observed good correlations between the mono-, di-, and triphosphates and their respective sums (R2 > 0.88) and the TGTP ratio (TGTP/(TGDP+TGTP)) was not different in patients with active disease or in clinical remission.Thiopurine metabolites should still be measured by the routine method, since the novel and technically more challenging method, including determination of TGTP and TGTP ratio, does not offer a clinical advantage compared to the routine method.
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