mercaptopurine and Drug-Related-Side-Effects-and-Adverse-Reactions

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.. 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.. English abstracts were identified in PubMed by multiple search terms. Full-length articles were selected for review, and secondary and tertiary bibliographies were developed.. 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.. 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.

Topics: Allopurinol; Azathioprine; Drug-Related Side Effects and Adverse Reactions; Guanine Nucleotides; Hepatitis, Autoimmune; Humans; Inflammatory Bowel Diseases; Mercaptopurine; Purines; Quality Improvement; Thioguanine; Thionucleotides; Treatment Outcome

Thiopurines have been widely used for the maintenance of remission or steroid sparing in patients with inflammatory bowel disease. However, potential drug-related adverse events frequently interfere with their use. Indeed, drug withdrawals associated with adverse reactions have been reported in approximately 25% of patients. To balance the efficacy, safety, and tolerability of thiopurines, regular monitoring of biomarkers (complete blood cell count, liver function test, and metabolic profiles), steady dose escalation, and pretreatment thiopurine S-methyltransferase (TPMT) genotype screening have been routinely recommended. However, the complex thiopurine metabolic pathway and individual differences attributed to pharmacogenetic diversity limit the effectiveness of these strategies in the optimization of thiopurine therapy. Recently, in an effort to facilitate more accurate and personalized prediction of thiopurine response or toxicity, novel genetic markers including NUDT15 and FTO genes were discovered. These discoveries are remarkable because TPMT screening has minimal efficacy for predicting myelosuppression especially in Asian populations, despite the fact that thee populations have a higher frequency of myelosuppression than Western populations. This review focuses on the current understanding of the metabolic pathway and the pharmacogenetics of thiopurines and suggests a personalized preventive strategy against potential adverse drug reactions to optimize their therapeutic application.

Topics: Alpha-Ketoglutarate-Dependent Dioxygenase FTO; Azathioprine; Colitis, Ulcerative; Crohn Disease; Drug-Related Side Effects and Adverse Reactions; Humans; Mercaptopurine; Metabolic Networks and Pathways; Methyltransferases; Pharmacogenomic Testing; Pyrophosphatases; Thioguanine

Azathioprine and 6-mercaptopurine remain pivotal therapies for the maintenance of disease remission in patients with Crohn's disease and ulcerative colitis. While thiopurine S-methyltransferase deficiency was the first pharmacogenetic phenomenon to be recognized to influence thiopurine toxicity and reliably predict leukopenia, it does not predict other adverse effects, nor does it explain most cases of thiopurine resistance. In recent years, a number of other genetic polymorphisms have received increasing attention in the literature. In particular, SNPs in NUDT15 and in the class II HLA locus have been shown to predict thiopurine-related leukopenia and pancreatitis. The aim of this review is to provide a concise update of genetic variability which may influence patient response to azathioprine and 6-mercaptopurine.

Topics: Azathioprine; Colitis, Ulcerative; Crohn Disease; Drug Hypersensitivity; Drug-Related Side Effects and Adverse Reactions; Genotype; Histocompatibility Antigens Class II; Humans; Inflammatory Bowel Diseases; Mercaptopurine; Pharmacogenetics; Polymorphism, Single Nucleotide; Purine-Pyrimidine Metabolism, Inborn Errors; Pyrophosphatases

Historically genetics has not been considered when prescribing drugs for children. However, it is clear that genetics are not only an important determinant of disease in children but also of drug response for many important drugs that are core agents used in the therapy of common problems in children. Advances in therapy and in the ethical construct of children's research have made pharmacogenomic assessment for children much easier to pursue. It is likely that pharmacogenomics will become part of the therapeutic decision making process for children, notably in areas such as childhood cancer where the benefits and risks of therapy are considerable.

Topics: Child; Codeine; Drug Discovery; Drug-Related Side Effects and Adverse Reactions; Humans; Mercaptopurine; Neoplasms; Pediatrics; Pharmacogenetics; Precision Medicine

To evaluate the relationship between thiopurine S-methyltransferase (TPMT) polymorphisms and thiopurine-induced adverse drug reactions (ADRs) in inflammatory bowel disease (IBD).. Eligible articles that compared the frequency of TPMT polymorphisms among thiopurine-tolerant and -intolerant adult IBD patients were included. Statistical analysis was performed with Review Manager 5.0. Sub-analysis/sensitivity analysis was also performed.. Nine studies that investigated a total of 1309 participants met our inclusion criteria. The incidence of TPMT gene mutation was increased 2.93-fold (95% CI: 1.68-5.09, P = 0.0001) and 5.93-fold (95% CI: 2.96-11.88, P < 0.00001), respectively, in IBD patients with thiopurine-induced overall ADRs and bone marrow toxicity (BMT), compared with controls. The OR for TPMT gene mutation in IBD patients with thiopurine-induced hepatotoxicity and pancreatitis was 1.51 (95% CI: 0.54-4.19, P = 0.43) and 1.02 (95% CI: 0.26-3.99, P = 0.98) vs controls, respectively.. This meta-analysis suggests that the TPMT polymorphisms are associated with thiopurine-induced overall ADRs and BMT, but not with hepatotoxicity and pancreatitis.

Topics: Adult; Azathioprine; Databases, Factual; Drug-Related Side Effects and Adverse Reactions; Humans; Immunosuppressive Agents; Inflammatory Bowel Diseases; Mercaptopurine; Methyltransferases; Polymorphism, Genetic

Thiopurines have proven efficacy in inflammatory bowel disease. However, concerns regarding toxicity have limited the use of these agents as first line of medical therapy.. Review of the literature regarding metabolism, efficacy and side effects.. In clinical trials, up to 15% of patients discontinued 6-mercaptopurine or its pro-drug azathioprine prematurely due to adverse events. These events may be divided into dose-independent idiosyncratic reactions and dose-related, pharmacologically explainable toxicity. Dose-independent reactions include skin rash, fever, diarrhoea and pancreatitis. Most frequently observed dose-dependent adverse events are nausea, malaise and myelotoxicity. Furthermore, dose-dependent and dose-independent hepatotoxicity may occur. Recent insights obtained by therapeutic drug monitoring in patients on azathioprine or 6-mercaptopurine have led to strategies to reduce toxicity. One strategy is to detect poor metabolisers of thiopurines by establishing the activity of the key enzyme thiopurine methyltransferase. However, the clinical relevance of this strategy is still a point of debate. Another strategy is to administer 6-thioguanine, which is an agent close to the effective 6-thioguanine nucleotides.. Therapeutic drug monitoring of thiopurines resulted in strategies to reduce toxicity. The value of these strategies has yet to be proven in prospective randomized trials.

Topics: Azathioprine; Drug Monitoring; Drug-Related Side Effects and Adverse Reactions; Humans; Immunosuppressive Agents; Inflammatory Bowel Diseases; Mercaptopurine; Treatment Outcome

Topics: Aged; Agglutination Tests; Alkaloids; Alkylating Agents; Anti-Bacterial Agents; Anticonvulsants; Antigen-Antibody Reactions; Azathioprine; Blood Cell Count; Blood Platelet Disorders; Blood Platelets; Bone Marrow; Bone Marrow Examination; Clot Retraction; Complement Fixation Tests; Cytarabine; Drug-Related Side Effects and Adverse Reactions; Fluorouracil; Humans; Hypoglycemic Agents; Infant, Newborn; Kidney Function Tests; Liver Function Tests; Male; Mercaptopurine; Middle Aged; Prothrombin Time; Thrombocytopenia; Tranquilizing Agents; Vinblastine; Vincristine

Skewed drug metabolism of 6-mercaptopurine (6-MP) can jeopardize antileukemic effects and result in toxicities during the treatment of acute lymphoblastic leukemia and lymphoblastic lymphoma. Allopurinol can alter 6-MP metabolism to maximize therapeutic effects while reducing toxicities. Over 75% of our patients with acute lymphoblastic leukemia or lymphoblastic lymphoma experienced a 6-MP-related toxicity. Review of metabolite date a showed 6-methylmercaptopurine nucleotide levels were >10,000 in 55% of the cohort, suggesting 6-MP shunting. Allopurinol was initiated in 12 of 23 shunters with resolution of toxicities. We propose an algorithm to incorporate allopurinol into chemotherapy regimens for patients with inappropriate 6-MP metabolism.

Topics: Adolescent; Adult; Algorithms; Allopurinol; Antimetabolites; Antimetabolites, Antineoplastic; Child; Child, Preschool; Drug Therapy, Combination; Drug-Related Side Effects and Adverse Reactions; Female; Follow-Up Studies; Humans; Infant; Infant, Newborn; Lymphoma, Non-Hodgkin; Male; Mercaptopurine; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Prognosis; Retrospective Studies; Young Adult

Thiopurines are effective therapies for inflammatory bowel disease (IBD); however, treatment comes with safety concerns and adverse effects. Knowledge of the impact of pharmacists performing thiopurine monitoring is limited.. To determine the impact of a pharmacist-led monitoring service in patients with IBD commencing thiopurine therapy managed in the ambulatory care setting.. Patients commencing thiopurine therapy for IBD pre- and post-introduction of a pharmacist-led monitoring intervention were assessed. Pre-intervention patients received standard of care, while the post-intervention cohort was managed by the pharmacist. Data were acquired via retrospective audit of hospital medical records. The primary end-point was the proportion of patients with documented review for thiopurine adverse effects within the initial 3 weeks. Secondary end-points included achievement of therapeutic drug levels, persistence with thiopurine therapy, IBD-related episodes of care and number of outpatient medical reviews.. Pre- and post-intervention cohorts comprised of 37 and 33 patients respectively. Pharmacist intervention increased the proportion of patients with documented monitoring within 3 weeks from 8.1% to 84.8% (P < 0.01). No difference in thiopurine dose optimisation was seen (27% vs 27.3%). Persistence with thiopurine therapy increased from 65.7% to 87.9% (P < 0.03) at 6 months. IBD-related emergency department presentations were not significantly decreased (8.1% vs 3%; P = 0.62). No significant change was observed in hospital admissions (16.2% vs 12.1%; P = 0.74) or outpatient medical reviews.. Pharmacist monitoring of thiopurine therapy initiation in IBD outpatients improves adverse effect monitoring and increases medication persistence.

Topics: Azathioprine; Drug-Related Side Effects and Adverse Reactions; Humans; Inflammatory Bowel Diseases; Mercaptopurine; Outpatients; Pharmacists; Retrospective Studies

Approximately 25% of patients with inflammatory bowel disease (IBD) discontinue azathioprine (AZA) or mercaptopurine (MP) therapy within 3 months of treatment initiation because of adverse drug reactions. Of these side-effects, about half are because of hepatotoxicity. The aim of this study was to validate and (subsequently) optimize a previously reported predictive algorithm for thiopurine-associated hepatotoxicity by increasing the number of patients with IBD benefitting from conventional thiopurine therapy.. This multicenter observational study included consecutive thiopurine-naive patients with IBD who received AZA or MP treatment. The primary outcome was hepatotoxicity within 12 weeks. The patients with and without hepatotoxicity were compared. Four determinants, namely, age, sex, body mass index (BMI), and 6-methylmercaptopurine ribonucleotide concentrations 1 week after treatment initiation (T = 1) were used to validate and optimize 2 (1 dichotomous and 1 continuous) algorithms using multivariable logistic regression analysis.. Of 229 patients, 21 (9%) developed hepatotoxicity and 93% of the patients received MP with a median dose of 0.7 mg/kg (95% confidence interval 0.3-1.4 mg/kg). A difference in BMI was found between with and without hepatotoxicity groups (median 27.6 versus 24.2, P = 0.022). Specificities of 68% (Algorithm 1) and 77% (Algorithm 2) and sensitivities of 56% (Algorithm 1) and 50% (Algorithm 2) were obtained.. Both algorithms demonstrated limited predictive accuracy for thiopurine-induced hepatotoxicity in the validation cohort. Relevant factors contributing to this outcome were changes in thiopurine prescription behavior over time, with more MP prescriptions at relatively lower dosages of MP.

Topics: Algorithms; Azathioprine; Chemical and Drug Induced Liver Injury; Drug-Related Side Effects and Adverse Reactions; Humans; Immunosuppressive Agents; Inflammatory Bowel Diseases; Mercaptopurine

In the recent era of growing availability of biological agents, the role of thiopurines needs to be reassessed with the focus on toxicity.. We assessed the incidence and predictive factors of thiopurine-induced adverse events (AE) resulting in therapy cessation in pediatric inflammatory bowel disease (IBD), related to thiopurine metabolites and biochemical abnormalities, and determined overall drug survival.. We performed a retrospective, single-center study of children diagnosed with IBD between 2000 and 2019 and treated with thiopurine therapy. The incidence of AE and overall drug survival of thiopurines were evaluated using the Kaplan-Meier method. Correlations between thiopurine metabolites and biochemical tests were computed using Spearman's correlation coefficient.. Of 391 patients with IBD, 233 patients (162 Crohn's disease, 62 ulcerative colitis, and 9 IBD-unclassified) were prescribed thiopurines (230 azathioprine and 3 mercaptopurine), of whom 50 patients (22%) discontinued treatment, at least temporary, due to thiopurine-induced AE (median follow-up 20.7 months). Twenty-six patients (52%) were rechallenged and 18 of them (70%) tolerated this. Sixteen patients (6%) switched to a second thiopurine agent after azathioprine intolerance and 10 of them (63%) tolerated this. No predictive factors for development of AE could be identified. Concentrations of 6-thioguanine nucleotides (6-TGN) were significantly correlated with white blood cell and neutrophil count, 6-methylmercaptopurine (6-MMP) concentrations with alanine aminotransferase and gamma-glutamyltranspeptidase.. Approximately 20% of pediatric patients with IBD discontinued thiopurine treatment due to AE. A rechallenge or switch to mercaptopurine is an effective strategy after development of AE. Concentrations of 6-TGN and 6-MMP are associated with biochemical abnormalities.

Topics: Adolescent; Antimetabolites; Azathioprine; Biomarkers, Pharmacological; Child; Cohort Studies; Colitis, Ulcerative; Crohn Disease; Drug Substitution; Drug-Related Side Effects and Adverse Reactions; Female; Guanine Nucleotides; Humans; Male; Mercaptopurine; Netherlands; Retrospective Studies; Thionucleotides; Withholding Treatment

Thiopurines are effectively prescribed for immune and oncology diseases but their toxicity leads to severe myelosuppression. Therefore, TPMT genetic variants have been used to adjust dosing for poor and intermediate metabolizers, significantly preventing adverse drug reactions. In 2018, the Clinical Pharmacogenetics Implementation Consortium included NUDT15 rs116855232 to also guide thiopurines dosing. This variant is not present in Caucasians but have been identified in 10% of Asian and Latin American populations. Despite research efforts to portrait the world's genetic variation, few studies include the investigation of NUDT15 in large samples.. Fifteen NUDT15 and TPMT variants were retrieved for 1270 Mestizos and 20 Natives genotyped from previous studies using the GSA-Illumina microarray. After bioinformatic quality controls, genotypes were available for 12 variants, TPMT rs2842949, rs2842950, rs2842934, rs1800460, rs12201199, rs12663332, rs2518463, rs4449636, rs12529220, rs3931660, rs200591577, and NUD15 rs116855232. Allele frequencies and haplotypes were assessed using PLINK, R, and Haploview. Dosing inferences were described according to the Clinical Pharmacogenomics Implementation Consortium.. We report relevant populations differences in actionable TPMT*3B and NUDT15 rs116855232 as the allele frequency of the former is higher in Mestizos compared to Caucasians, and for the latter we report twofold and 1.35-fold higher allele frequencies in Natives and Mestizos compared to Mexicans from Los Angeles.. TPMT*3B and NUDT15 rs116855232 actionable markers showed population differences that ought to be considered as dosing inferences highlight the relevance of routine genotyping of these variants for the prescription of thiopurines in Mexican populations.

Topics: Dose-Response Relationship, Drug; Drug-Related Side Effects and Adverse Reactions; Female; Gene Frequency; Humans; Male; Mercaptopurine; Methyltransferases; Mexico; Pharmacogenetics; Pharmacogenomic Variants; Pyrophosphatases

Although combining thiopurine with infliximab (IFX) is considered to improve the clinical efficacy of IFX when treating Crohn's disease (CD), it also increases the risk of adverse events (AEs). We compared the efficacy and safety of delayed thiopurine addition after loss of response (LOR) to IFX with the efficacy and safety of an earlier combination of thiopurine and IFX.. This retrospective study analyzed patients with CD who started IFX as a first-line biologic at Kyushu University Hospital between June 2002 and July 2018. Patients were assigned to either the early-combination (EC) group, who started IFX and thiopurine simultaneously, or the late-combination (LC) group, who were treated with IFX alone until they developed LOR. We compared the cumulative IFX continuation rates and AE incidence between the two groups.. One hundred seventy-six patients were enrolled in this study; 49 were enrolled in the EC group, and 127 were enrolled in the LC group. Disease activity at baseline did not significantly differ between the groups, nor did the cumulative IFX continuation rates differ between the groups (P = 0.30); however, the AE rate was significantly higher in the EC group than in the LC group (38.7% vs. 21.2%; P = 0.02). The severe AE rate was also higher in the EC group than in the LC group (18.3% vs 3.1%; P = 0.001).. Considering the risk-benefit balance, delayed addition of thiopurine after LOR to IFX might be an alternative strategy when using IFX to treat CD.

Topics: Adult; Antimetabolites; Azathioprine; Biological Products; Crohn Disease; Drug Monitoring; Drug Synergism; Drug Therapy, Combination; Drug-Related Side Effects and Adverse Reactions; Female; Humans; Infliximab; Japan; Male; Mercaptopurine; Retrospective Studies; Risk Assessment; Treatment Outcome

Inflammatory bowel disease (IBD) frequently requires chronic immunosuppressive treatment and active involvement from patients during treatment decision making. Information about the risk of developing adverse drug reactions (ADRs) to IBD therapies is required in this process.. The aim of this study was to describe the ADRs reported in IBD patients from real-world data, using the Dutch nationwide IBDREAM registry, and compare the occurrence and cumulative incidences with the Summary of Product Characteristics (SmPC) of the associated drugs.. In this retrospective multicentre study, ADRs related to IBD medication were assessed. Only reports associated with the use of drugs used for the maintenance treatment of IBD were included. All ADRs were verified by healthcare professionals and coded by trained pharmacovigilance assessors.. In total, 3080 ADRs were reported in 1179 patients. Twenty-three new drug-ADR associations related to the use of azathioprine, mercaptopurine, infliximab, oral mesalamine and thioguanine were reported in the IBDREAM registry that were not mentioned in the corresponding SmPCs. The most frequently reported new association was pyrexia for azathioprine (3.1%) and mercaptopurine (4.9%). In addition, there were seven ADRs with a higher cumulative incidence in IBDREAM compared with the SmPC, and included, among others, arthralgia during mercaptopurine use (2.5%), and diarrhoea (1.4%), alopecia (1.2%) and infections (1.6%) during azathioprine use.. Based on real-world data, ADR reporting demonstrated new ADRs and higher incidences of ADRs to IBD therapies. This information will contribute to drug safety by updating the SmPCs, allowing better risk assessment and communication towards patients.

Topics: Adverse Drug Reaction Reporting Systems; Azathioprine; Drug-Related Side Effects and Adverse Reactions; Humans; Inflammatory Bowel Diseases; Mercaptopurine; Pharmacovigilance; Registries; Retrospective Studies

Topics: Allopurinol; Chemical and Drug Induced Liver Injury; Drug-Related Side Effects and Adverse Reactions; Humans; Mercaptopurine; Precursor Cell Lymphoblastic Leukemia-Lymphoma

Although commonly used in inflammatory bowel disease [IBD], thiopurines frequently cause intolerance, and switching to a second thiopurine has only been reported in some small series. Ours aims in this study were to evaluate the safety of switching to a second thiopurine in a large cohort, and to assess the impact of age on tolerance.. Adult IBD patients from the ENEIDA registry, who were switched to a second thiopurine due to adverse events [excluding malignancies and infections], were identified. At the beginning of thiopurine treatment, patients were divided by age into two groups: 18-50 and over 60 years of age. The rate and concordance of adverse events between the first and second thiopurines, treatment intolerance, and persistence with the second thiopurine were evaluated.. A total of 1278 patients [13% over 60 years of age] were switched to a second thiopurine. At 12 months, the cumulative probability of switch intolerance was 43%, and persistence with treatment was 49%. Independent risk factors of switch intolerance were age over 60 years (odds ratio [OR] 1.49; 95% confidence interval [CI] 1.07-2.07; p = 0.017) , previous gastrointestinal toxicity [OR 1.4; 95% CI 1.11-1.78; p = 0.005], previous acute pancreatitis [OR 6.78; 95% CI 2.55-18.05; p <0.001], and exposure to the first thiopurine <6 months [OR 1.59; 95% CI 1.14-2.23; p = 0.007].. In a large series in clinical practice, switching to a second thiopurine proved to be a valid strategy. Tight monitoring of elderly IBD patients switching to a second thiopurine because of adverse events is recommended.

Topics: Adult; Age Factors; Aged; Azathioprine; Drug Monitoring; Drug Substitution; Drug Tolerance; Drug-Related Side Effects and Adverse Reactions; Female; Humans; Immunosuppressive Agents; Inflammatory Bowel Diseases; Male; Mercaptopurine; Practice Patterns, Physicians'; Risk Adjustment; Spain

To timely detect myelotoxicity and hepatotoxicity, laboratory monitoring at 3-month intervals is advised throughout thiopurine maintenance treatment for IBD. However, reported incidence rates of myelotoxicity and hepatotoxicity in maintenance treatment are low.. To assess incidence rates and clinical consequences of myelotoxicity and hepatotoxicity in thiopurine maintenance therapy after at least 1 year of thiopurine treatment.. Retrospective analysis of therapy adjustment for laboratory toxicity in adult IBD patients after 12 consecutive months of azathioprine (AZA) or mercaptopurine monotherapy (ie baseline) between 2000 and 2016. Incidence rates of laboratory toxicity (ie myelotoxicity [leucocyte count <4.0 × 10e9/L, and/or platelet count <150 × 10e9/L] and/or hepatotoxicity (gamma-glutamyltransferase [GGT], alkaline phosphatase [AP], ALT and/or AST above ULN, excluding isolated increased AST/AP]) and associated diagnostic procedures and complications were assessed.. In total, 12,391 laboratory assessments were performed on 1132 patients (56% female, AZA 74%) during 3.3 years of median follow-up. Median monitoring frequency was 3.1 assessments/treatment year. Only 83/12,391 (0.7%) assessments resulted in therapy adjustment, dose reduction in 46 patients, cessation in 28 and allopurinol initiation in nine; risk of therapy adjustment was 1.9% per treatment year. Incidence rates of myelotoxicity were 7.1% (5.1% mild/1.8% moderate/0.1% severe) and hepatotoxicity 5.1% (3.8% mild/1.1% moderate/0.2% severe) per treatment year. Treatment-related complications with concurrent laboratory toxicity occurred in 12 patients (1.1%) and would not have been prevented by monitoring.. Severe laboratory toxicity is uncommon after 1 year of thiopurine monotherapy at 4-month monitoring intervals. Therapy adjustments are rare after detection of laboratory toxicity. After 1 year of thiopurine monotherapy, laboratory monitoring may be lowered to less than a 4-month interval.

Topics: Adult; Allopurinol; Azathioprine; Clinical Laboratory Techniques; Drug Monitoring; Drug-Related Side Effects and Adverse Reactions; Female; Follow-Up Studies; Humans; Immunosuppressive Agents; Inflammatory Bowel Diseases; Maintenance Chemotherapy; Male; Mercaptopurine; Middle Aged; Netherlands; Predictive Value of Tests; Prognosis; Purines; Retrospective Studies; Young Adult

Thiopurines are used as maintenance therapy in ulcerative colitis (UC), but whether these drugs influence the natural history of the disease is unknown. We aimed to assess the effect of thiopurines in terms of colectomy, hospital admission, progression in disease extent and anti-tumour necrosis factor (TNF) therapy within 10 years from initiation.. Patients diagnosed with UC within the Örebro University Hospital catchment area, during 1963-2010, who initiated thiopurines (n=253) were included. To overcome the risk of confounding by indication, we compared patients who stopped treatment within 12 months because of an adverse reaction (n=76) with patients who continued therapy or discontinued due to other reasons (n=177) and assessed long-term outcomes using Cox regression with adjustment for potential confounding factors.. The cumulative probability of colectomy within 10 years was 19.5% in tolerant patients compared with 29.0% in intolerant (adjusted HR 0.49; 95% CI 0.21 to 0.73). The probability of hospital admission was 34.0% in tolerant versus 56.2% in intolerant patients (adjusted HR 0.36; 95% CI 0.23 to 0.56). The risk for progression in disease extent was 20.4% in tolerant patients compared with 48.8% in intolerant (adjusted HR 0.47; 95% CI 0.21 to 1.06). Within 10 years, 16.1% of tolerant and 27.5% of intolerant patients received anti-TNF therapy (adjusted HR 0.49; 95% CI 0.26 to 0.92).. Based on the novel approach of comparing patients tolerant and intolerant to thiopurines, we reveal that thiopurines have a profound beneficial impact of the natural history and long-term colectomy rates of UC.

Topics: Adult; Azathioprine; Colectomy; Colitis, Ulcerative; Disease Progression; Drug-Related Side Effects and Adverse Reactions; Female; Hospitalization; Humans; Immunosuppressive Agents; Male; Mercaptopurine; Middle Aged; Thioguanine; Treatment Outcome; Tumor Necrosis Factor-alpha

Low-dose thiopurine-allopurinol (LDTA) combination therapy is a commonly applied optimisation strategy in IBD patients with a skewed thiopurine metabolism.. To assess continued LDTA maintenance treatment at annual intervals and explore risk factors for treatment cessation METHODS: Adult IBD patients treated with LDTA between 2009 and 2016 were retrospectively included. Data on the incidence of clinical and laboratory adverse events (AEs), including hepatotoxicity and myelotoxicity resulting in imposing LDTA therapy cessation and associated risk factors were collected.. In total, 221 IBD patients (46% male, median age 42 years) were included. Maintenance LDTA treatment was continued in 78% of patients at 1 year (n = 145), 66% at 2 years (n = 83), 57% at 3 years (n = 52) and 52% at 4 years (n = 33). Treatment in patients receiving LDTA therapy for AEs during thiopurine monotherapy was more often continued than in patients initiating LDTA for other indications (eg, ineffectiveness of thiopurine monotherapy, routinely discovered skewed metabolism) (P = 0.016). Myelotoxicity during thiopurine monotherapy resolved in 87% and hepatotoxicity in 86% after median of 1.2 and 1.4 months after LDTA initiation. Cumulative incidence of AEs during LDTA resulting in therapy cessation within total follow-up of 449 treatment-years was 7% for clinical AEs, 4% for myelotoxicity and 1% for hepatotoxicity.. LDTA therapy is a safe and beneficial optimisation strategy in IBD patients. Continued maintenance LDTA treatment is 52% after 4 years of treatment and most commonly affected by ineffectiveness of LDTA rather than LDTA-attributed toxicity. LDTA optimisation strategy is most advantageous in patients failing thiopurine monotherapy due to AEs.

Topics: Adult; Allopurinol; Bone Marrow Diseases; Chemical and Drug Induced Liver Injury; Drug Therapy, Combination; Drug-Related Side Effects and Adverse Reactions; Female; Humans; Immunosuppressive Agents; Inflammatory Bowel Diseases; Male; Medication Adherence; Mercaptopurine; Middle Aged; Netherlands; Retrospective Studies; Withholding Treatment

Azathioprine (AZA) and mercaptopurine (MP) are the cornerstone of steroid-sparing strategies in autoimmune hepatitis (AIH). Up to 20% of patients do not tolerate or respond to these regimens.. To evaluate retrospectively the tolerability and efficacy of tioguanine (thioguanine) (TG) therapy in selected patients with AIH and AIH variant syndromes.. Records of 52 patients who received TG therapy were retrieved from nine hospitals in the Netherlands. Indications for TG treatment were intolerable side effects on AZA or MP (n = 38), insufficient response (n = 11) or first-line treatment (n = 3). Treatment efficacy was defined as normalisation of serum aminotransferases and serum immunoglobulin G.. No serious adverse events occurred in patients treated with TG during a median follow-up of 18 months (range 1-194). Treatment was well tolerated in 41 patients (79%), whereas four had tolerable (8%) and seven (13%) intolerable side effects. Thirty-eight patients were treated with TG after intolerable side effects on AZA or MP; 29 patients continued TG therapy of whom 24 (83%) achieved complete biochemical remission, four (14%) had incomplete and one (3%) had no response; nine discontinued treatment. Seven of 11 patients with insufficient response to AZA or MP were responsive to TG, three with complete and four with incomplete biochemical remission; four discontinued due to intolerance (n = 2) and non-response (n = 2). TG was effective in all AIH patients as first-line maintenance treatment.. In our retrospective review of TG therapy in selected patients with AIH or AIH variants who previously failed on AZA or MP, TG appeared tolerable with biochemical efficacy.

Topics: Adolescent; Adult; Aged; Azathioprine; Biomarkers; Child; Drug-Related Side Effects and Adverse Reactions; Female; Hepatitis, Autoimmune; Humans; Immunosuppressive Agents; Male; Mercaptopurine; Middle Aged; Netherlands; Remission Induction; Retrospective Studies; Thioguanine; Treatment Outcome; Young Adult

Thiopurines (azathioprine and mercaptopurine) are frequently used immunosuppressive drugs to maintain remission in patients with inflammatory bowel disease. Half of the conventional thiopurine-derivative users have to discontinue treatment within 5 years, mainly because of intolerable adverse events. Over recent years, different strategies to optimize thiopurine treatment were suggested, yet, studies describing the clinical effectiveness of these strategies remain scarce. The aims of this study were to compare tolerability and sustained clinical benefit of conventional thiopurine derivatives therapy among two 5-year real-life intercept cohorts and to assess the clinical value of specifically allopurinol cotherapy.. In this retrospective single-center cohort study, we analyzed data from patients in whom weight-based thiopurine monotherapy was initiated between 2005 and 2009 (cohort 1) or between 2010 and 2014 (cohort 2). The initiation of the second cohort was synchronic to the start of allopurinol-based optimization in our center. Optimization strategies were extracted from patient charts.. In total, 105 patients were included (60 in cohort 1, and 45 in cohort 2). Metabolite measurement was performed in 37% versus 84% of the patients (P < 0.001). Subsequent optimization strategies were applied in 33% versus 58% of the patients because of inadequate metabolite concentrations, intolerance, or ineffectiveness (P = 0.01). Allopurinol was coadministered to therapy in 18 patients (40%) in the second cohort. Therapy was switched to thioguanine in 11 versus 6 patients (P > 0.05). Overall, total duration was longer in the second cohort (10.8 versus 34.1 months, P < 0.001). The number of ongoing thiopurine users (20% versus 49%) and sustained clinical benefit (13% versus 38%) were higher in the second cohort (both P < 0.05). This was mainly because of a decrease in hepatotoxicity after optimization (P < 0.01).. Optimization of thiopurine therapy by the use of therapeutic drug monitoring with subsequent administration of allopurinol cotherapy successfully enhanced sustained clinical benefit and tolerability in patients with inflammatory bowel disease.

Topics: Adult; Allopurinol; Azathioprine; Drug Monitoring; Drug Therapy, Combination; Drug-Related Side Effects and Adverse Reactions; Female; Humans; Immunosuppressive Agents; Inflammatory Bowel Diseases; Male; Mercaptopurine; Middle Aged; Retrospective Studies; Thioguanine; Treatment Outcome; Young Adult

Thiopurine methyltransferase (TPMT) gene polymorphism regulates thiopurine therapeutic efficacy and toxicity. The aim of this study was to determine the influence of TPMT gene polymorphism in Egyptian children with acute lymphoblastic leukaemia (ALL). Sixty-four patients with ALL, T lineage (27%) and pre-B phenotype (73%), who were treated with BFM 90 or CCG 1991 standard risk protocol, and who also experiencedmyleosuppresion toxicity and required interruption and/ormodification of thiopurine chemotherapy were recruited over a year period. Thirty-two patients were on maintenance and another 32 completed their chemotherapy. Seventy healthy age-matched and sex-matched children served as controls. They were subjected to clinical assessment, haematological panel investigations and TPMT gene polymorphism for G238C, G460A and A719G alleles assessment using PCRfollowed byRFLP analysis.Although none of the studied patients had themutantTPMTvariant alleles,myelosuppression toxicity in the form of different degree of neutropenia was detected in all patients. As a result of myelosuppression toxicity, most of the patients needed 6-MP dose modification either once (53.1%), twice (15.6%), or ≥ thrice (25.1%) during their maintenance course and 96.9% of the patients required to stop 6-MP for less than a week (62.5%), up to 2 weeks (28.1%), or > 2 weeks (6.3%). Patients also developed infection who mostly (71%) needed hospitalization. None of the studied G238C, G460A and A719G TPMT variant alleles were detected. Infections and febrile neutropenia were common causes of 6-PM dose modification and interruption.

Topics: Adolescent; Alleles; Antineoplastic Combined Chemotherapy Protocols; Asparaginase; Child; Child, Preschool; Daunorubicin; Drug-Related Side Effects and Adverse Reactions; Female; Genetic Association Studies; Genetic Predisposition to Disease; Genotype; Humans; Infant; Male; Mercaptopurine; Methyltransferases; Polymorphism, Single Nucleotide; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Prednisone; Vincristine

Adequate maintenance therapy for childhood acute lymphoblastic leukemia (ALL), with 6-mercaptopurine as an essential component, is necessary for retaining durable remission. Interruptions or discontinuations of the therapy due to drug-related toxicities, which can be life threatening, may result in an increased risk of relapse. In this retrospective study including 305 paediatric ALL patients undergoing maintenance therapy, we systematically investigated the individual and combined effects of genetic variants of folate pathway enzymes, as well as of polymorphisms in PACSIN2 and ITPA, on drug-induced toxicities by applying a multi-analytical approach including logistic regression (LR), classification and regression tree (CART) and generalized multifactor dimensionality reduction (GMDR). In addition to the TPMT genotype, confirmed to be a major determinant of drug related toxicities, we identified the PACSIN2 rs2413739TT genotype as being a significant risk factor for 6-MP-induced toxicity in wild-type TPMT patients. A gene-gene interaction between MTRR (rs1801394) and MTHFR (rs1801133) was detected by GMDR and proved to have an independent effect on the risk of stomatitis, as shown by LR analysis. To our knowledge, this is the first study showing PACSIN2 genotype association with hematological toxicity in ALL patients undergoing maintenance therapy.

Topics: Adaptor Proteins, Signal Transducing; Child; Child, Preschool; Drug-Related Side Effects and Adverse Reactions; Female; Ferredoxin-NADP Reductase; Folic Acid; Genetic Association Studies; Genetic Predisposition to Disease; Genotype; Humans; Male; Mercaptopurine; Metabolic Networks and Pathways; Methylenetetrahydrofolate Reductase (NADPH2); Polymorphism, Single Nucleotide; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Pyrophosphatases

Topics: Antidepressive Agents; Child; Dideoxynucleosides; Drug Hypersensitivity; Drug-Related Side Effects and Adverse Reactions; Evidence-Based Medicine; Genetic Testing; HIV Infections; HLA-B Antigens; Humans; Male; Mercaptopurine; Pharmacogenetics; Precision Medicine; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Primaquine; Purine-Pyrimidine Metabolism, Inborn Errors; Succinylcholine; Warfarin

Topics: Adaptor Proteins, Signal Transducing; Drug-Related Side Effects and Adverse Reactions; Female; Gastrointestinal Tract; Humans; Male; Mercaptopurine; Methyltransferases

The bile salt export pump (BSEP) is expressed at the canalicular domain of hepatocytes, where it serves as the primary route of elimination for monovalent bile acids (BAs) into the bile canaliculi. The most compelling evidence linking dysfunction in BA transport with liver injury in humans is found with carriers of mutations that render BSEP nonfunctional. Based on mounting evidence, there appears to be a strong association between drug-induced BSEP interference and liver injury in humans; however, causality has not been established. For this reason, drug-induced BSEP interference is best considered a susceptibility factor for liver injury as other host- or drug-related properties may contribute to the development of hepatotoxicity. To better understand the association between BSEP interference and liver injury in humans, over 600 marketed or withdrawn drugs were evaluated in BSEP expressing membrane vesicles. The example of a compound that failed during phase 1 human trials is also described, AMG 009. AMG 009 showed evidence of liver injury in humans that was not predicted by preclinical safety studies, and BSEP inhibition was implicated. For 109 of the drugs with some effect on in vitro BSEP function, clinical use, associations with hepatotoxicity, pharmacokinetic data, and other information were annotated. A steady state concentration (C(ss)) for each of these annotated drugs was estimated, and a ratio between this value and measured IC₅₀ potency values were calculated in an attempt to relate exposure to in vitro potencies. When factoring for exposure, 95% of the annotated compounds with a C(ss)/BSEP IC₅₀ ratio ≥ 0.1 were associated with some form of liver injury. We then investigated the relationship between clinical evidence of liver injury and effects to multidrug resistance-associated proteins (MRPs) believed to play a role in BA homeostasis. The effect of 600+ drugs on MRP2, MRP3, and MRP4 function was also evaluated in membrane vesicle assays. Drugs with a C(ss)/BSEP IC₅₀ ratio ≥ 0.1 and a C(ss)/MRP IC₅₀ ratio ≥ 0.1 had almost a 100% correlation with some evidence of liver injury in humans. These data suggest that integration of exposure data, and knowledge of an effect to not only BSEP but also one or more of the MRPs, is a useful tool for informing the potential for liver injury due to altered BA transport.

Topics: Animals; ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily B, Member 11; ATP-Binding Cassette Transporters; Biological Transport; Chemical and Drug Induced Liver Injury; Cluster Analysis; Drug-Related Side Effects and Adverse Reactions; Humans; Liver; Male; Multidrug Resistance-Associated Proteins; Pharmacokinetics; Rats; Rats, Sprague-Dawley; Recombinant Proteins; Risk Assessment; Risk Factors; Toxicity Tests

Methotrexate is an immunosuppressant that is used to treat patients with Crohn's disease (CD). However, there are few data on the long-term effects of methotrexate maintenance therapy for these patients. We assessed the sustained clinical benefits and tolerability of methotrexate monotherapy after thiopurine therapy in patients with CD.. We analyzed data from 3 hospitals on 174 consecutive patients with CD (age, 35 ± 12 y) who received methotrexate monotherapy after thiopurine therapy (23% also did not respond to anti-tumor necrosis factor therapy) from 2000 to 2010. We assessed patient characteristics and the tolerability and sustained clinical benefits of the treatment. Sustained clinical benefit was defined as ongoing use of methotrexate or intentional discontinuation of successful therapy before the end-of-study point.. The number of patients with sustained clinical benefits from methotrexate monotherapy were 98 (86%), 50 (63%), 27 (47%), and 3 (20%), at 6, 12, 24, and 60 months, respectively. Forty-five patients (26%) discontinued methotrexate because of intolerance, particularly within 6 months after therapy began. Adverse responses generally were mild; only 1 patient required admission to the hospital for infection with cytomegalovirus, and no drug-related deaths were reported. Intolerance of the preceding thiopurine therapy was associated with adverse events during methotrexate therapy.. In a large cohort study of patients who received methotrexate monotherapy after thiopurine therapy for CD, 47% continued to receive the therapy or intentionally discontinued successful therapy within 2 years, and 20% did so within 5 years. Long-term use of methotrexate was well tolerated and relatively safe.

Topics: Adolescent; Adult; Crohn Disease; Drug-Related Side Effects and Adverse Reactions; Female; Humans; Immunosuppressive Agents; Male; Mercaptopurine; Methotrexate; Retrospective Studies; Treatment Outcome; Young Adult

Drug-induced liver injury is the most common cause of market withdrawal of pharmaceuticals, and thus, there is considerable need for better prediction models for DILI early in drug discovery. We present a study involving 223 marketed drugs (51% associated with clinical hepatotoxicity; 49% non-hepatotoxic) to assess the concordance of in vitro bioactivation data with clinical hepatotoxicity and have used these data to develop a decision tree to help reduce late-stage candidate attrition. Data to assess P450 metabolism-dependent inhibition (MDI) for all common drug-metabolizing P450 enzymes were generated for 179 of these compounds, GSH adduct data generated for 190 compounds, covalent binding data obtained for 53 compounds, and clinical dose data obtained for all compounds. Individual data for all 223 compounds are presented here and interrogated to determine what level of an alert to consider termination of a compound. The analysis showed that 76% of drugs with a daily dose of <100 mg were non-hepatotoxic (p < 0.0001). Drugs with a daily dose of ≥100 mg or with GSH adduct formation, marked P450 MDI, or covalent binding ≥200 pmol eq/mg protein tended to be hepatotoxic (∼ 65% in each case). Combining dose with each bioactivation assay increased this association significantly (80-100%, p < 0.0001). These analyses were then used to develop the decision tree and the tree tested using 196 of the compounds with sufficient data (49% hepatotoxic; 51% non-hepatotoxic). The results of these outcome analyses demonstrated the utility of the tree in selectively terminating hepatotoxic compounds early; 45% of the hepatotoxic compounds evaluated using the tree were recommended for termination before candidate selection, whereas only 10% of the non-hepatotoxic compounds were recommended for termination. An independent set of 10 GSK compounds with known clinical hepatotoxicity status were also assessed using the tree, with similar results.

Topics: Chemical and Drug Induced Liver Injury; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System; Decision Trees; Drug Evaluation, Preclinical; Drug-Related Side Effects and Adverse Reactions; Glutathione; Humans; Liver; Pharmaceutical Preparations; Protein Binding

Treatment-related toxicity can be life-threatening and is the primary cause of interruption or discontinuation of chemotherapy for acute lymphoblastic leukemia (ALL), leading to an increased risk of relapse. Mercaptopurine is an essential component of continuation therapy in all ALL treatment protocols worldwide. Genetic polymorphisms in thiopurine S-methyltransferase (TPMT) are known to have a marked effect on mercaptopurine metabolism and toxicity; however, some patients with wild-type TPMT develop toxicity during mercaptopurine treatment for reasons that are not well understood. To identify additional genetic determinants of mercaptopurine toxicity, a genome-wide analysis was performed in a panel of human HapMap cell lines to identify trans-acting genes whose expression and/or single-nucleotide polymorphisms (SNPs) are related to TPMT activity, then validated in patients with ALL. The highest ranking gene with both mRNA expression and SNPs associated with TPMT activity in HapMap cell lines was protein kinase C and casein kinase substrate in neurons 2 (PACSIN2). The association of a PACSIN2 SNP (rs2413739) with TPMT activity was confirmed in patients and knock-down of PACSIN2 mRNA in human leukemia cells (NALM6) resulted in significantly lower TPMT activity. Moreover, this PACSIN2 SNP was significantly associated with the incidence of severe gastrointestinal (GI) toxicity during consolidation therapy containing mercaptopurine, and remained significant in a multivariate analysis including TPMT and SLCO1B1 as covariates, consistent with its influence on TPMT activity. The association with GI toxicity was also validated in a separate cohort of pediatric patients with ALL. These data indicate that polymorphism in PACSIN2 significantly modulates TPMT activity and influences the risk of GI toxicity associated with mercaptopurine therapy.

Topics: Adaptor Proteins, Signal Transducing; Cell Line, Tumor; Child; Child, Preschool; Drug-Related Side Effects and Adverse Reactions; Female; Gastrointestinal Tract; Gene Expression; Genome-Wide Association Study; Genotype; HapMap Project; Humans; Male; Mercaptopurine; Methyltransferases; Polymorphism, Single Nucleotide; Precursor Cell Lymphoblastic Leukemia-Lymphoma

Drug-induced liver injury (DILI) is a leading cause of drugs failing during clinical trials and being withdrawn from the market. Comparative analysis of drugs based on their DILI potential is an effective approach to discover key DILI mechanisms and risk factors. However, assessing the DILI potential of a drug is a challenge with no existing consensus methods. We proposed a systematic classification scheme using FDA-approved drug labeling to assess the DILI potential of drugs, which yielded a benchmark dataset with 287 drugs representing a wide range of therapeutic categories and daily dosage amounts. The method is transparent and reproducible with a potential to serve as a common practice to study the DILI of marketed drugs for supporting drug discovery and biomarker development.

Topics: Animals; Benchmarking; Biomarkers, Pharmacological; Chemical and Drug Induced Liver Injury; Drug Design; Drug Labeling; Drug-Related Side Effects and Adverse Reactions; Humans; Pharmaceutical Preparations; Reproducibility of Results; United States; United States Food and Drug Administration

Drug-induced liver injury (DILI) is a significant concern in drug development due to the poor concordance between preclinical and clinical findings of liver toxicity. We hypothesized that the DILI types (hepatotoxic side effects) seen in the clinic can be translated into the development of predictive in silico models for use in the drug discovery phase. We identified 13 hepatotoxic side effects with high accuracy for classifying marketed drugs for their DILI potential. We then developed in silico predictive models for each of these 13 side effects, which were further combined to construct a DILI prediction system (DILIps). The DILIps yielded 60-70% prediction accuracy for three independent validation sets. To enhance the confidence for identification of drugs that cause severe DILI in humans, the "Rule of Three" was developed in DILIps by using a consensus strategy based on 13 models. This gave high positive predictive value (91%) when applied to an external dataset containing 206 drugs from three independent literature datasets. Using the DILIps, we screened all the drugs in DrugBank and investigated their DILI potential in terms of protein targets and therapeutic categories through network modeling. We demonstrated that two therapeutic categories, anti-infectives for systemic use and musculoskeletal system drugs, were enriched for DILI, which is consistent with current knowledge. We also identified protein targets and pathways that are related to drugs that cause DILI by using pathway analysis and co-occurrence text mining. While marketed drugs were the focus of this study, the DILIps has a potential as an evaluation tool to screen and prioritize new drug candidates or chemicals, such as environmental chemicals, to avoid those that might cause liver toxicity. We expect that the methodology can be also applied to other drug safety endpoints, such as renal or cardiovascular toxicity.

Topics: Animals; Anti-Infective Agents; Anti-Inflammatory Agents; Chemical and Drug Induced Liver Injury; Databases, Factual; Drug-Related Side Effects and Adverse Reactions; Humans; Liver; Models, Biological; Predictive Value of Tests

This study aimed to investigate whether there was a correlation between the genotype or haplotype of the methylenetetrahydrofolate reductase gene (MTHFR) and toxicities during consolidation therapy or plasma methotrexate (MTX) levels at 48 h after the first dose of MTX infusion. We retrospectively genotyped 181 children with newly diagnosed acute lymphoblastic leukemia (ALL) who were treated with the Chinese Children's Leukemia Group protocol. In standard- and medium-risk treatment branches, the 677T carriers (CT + TT) had a higher risk of developing thrombocytopenia when compared with carriers of the CC genotype (odds ratio [OR] 5.21, 95% confidence interval [CI] 1.18-23.01, p = 0.017). The 1298AC/CC genotypes were associated with a decrease in skin toxicity, as compared with the common AA genotype (p = 0.037). An estimation of haplotype frequencies showed that there was no 677T-1298C haplotype in the population. A lower frequency of anemia (OR 0.44, 95% CI 0.21-0.90, p = 0.025) and lower MTX level (p = 0.044) were observed in patients with the 677C-1298C haplotype than in those without. High plasma MTX level was correlated with anemia (p = 0.011) and neutropenia (p = 0.044). In the high-risk group, the polymorphisms or plasma MTX levels were not correlated with any toxicity. Taken together, our data demonstrate that genotyping of MTHFR and measurement of plasma MTX levels might be useful to optimize MTX therapy.

Topics: Adolescent; Antineoplastic Combined Chemotherapy Protocols; Asian People; Child; Child, Preschool; China; Drug-Related Side Effects and Adverse Reactions; Female; Gene Frequency; Genotype; Haplotypes; Humans; Infant; Linkage Disequilibrium; Logistic Models; Male; Mercaptopurine; Methotrexate; Methylenetetrahydrofolate Reductase (NADPH2); Neutropenia; Polymorphism, Single Nucleotide; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Retrospective Studies; Skin Diseases; Thrombocytopenia

The thiopurine drugs, azathioprine and mercaptopurine (MP), are established treatments for IBD. However, therapeutic failure caused by adverse drug reactions occurs frequently.. To study combination of allopurinol with reduced-dose thiopurine in an attempt to avoid adverse drug reactions in the treatment of IBD.. Patients with drug reactions to full-dose thiopurines were recruited for combination therapy in two IBD centres in this retrospective study. Dosing was guided by measuring thiopurine methyltransferase (for UK patients) or thioguanine nucleotides and methyl-6MP (Australian patients). Response was monitored by clinical activity indices.. Of 41 patients, 25 had non-hepatic and 16 had hepatitic reactions. Clinical remission was achieved in 32 patients (78%) with a median follow-up of 41 weeks (range 0.5-400). Patients who did not respond to combination therapy tended to fail early with the same adverse reaction. The relative risk of having an adverse reaction with methyl-6MP in the top interquartile range was 2.7 (1.3-28) times that with methyl-6MP in the lower three quartiles (95% confidence interval).. The combined experience from our centres is the largest reported experience of this combination therapy strategy in IBD, and the first to provide evidence for benefit in thiopurine and allopurinol co-therapy to avoid non-hepatitic adverse drug reactions.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Allopurinol; Azathioprine; Drug Therapy, Combination; Drug-Related Side Effects and Adverse Reactions; Female; Humans; Immunosuppressive Agents; Inflammatory Bowel Diseases; London; Male; Mercaptopurine; Middle Aged; Queensland; Retrospective Studies; Treatment Outcome

Topics: Antineoplastic Combined Chemotherapy Protocols; Child; Drug-Related Side Effects and Adverse Reactions; Female; Hematopoietic Stem Cell Transplantation; Heterozygote; Humans; Male; Mercaptopurine; Methylenetetrahydrofolate Reductase (NADPH2); Methyltransferases; Mutation; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Retrospective Studies

Hepatotoxicity results in the withdrawal of thiopurines drugs, azathioprine (AZA) and mercaptopurine (MP), in up to 10% of patients with inflammatory bowel disease. Our group previously demonstrated that allopurinol with AZA/ciclosporin/steroid 'triple therapy' improved renal graft survival.. To confirm the hypothesis that allopurinol may alleviate thiopurine hepatotoxicity by similar mechanisms as proposed in our renal study.. Unselected patients with acute thiopurine hepatotoxicity were offered allopurinol co-therapy with low-dose AZA or MP. The starting AZA/MP dose was determined by thiopurine methyltransferase (TPMT) activity (two patients were intermediate TPMT); then this dose was reduced to 25% for allopurinol co-therapy. Response to treatment was assessed by clinical severity indices, endoscopy and blood tests.. Of 11 patients (three Crohn's disease, eight ulcerative colitis) treated, nine (82%) remain in long-term remission (median 42 months) with normal liver tests. One patient also successfully bypassed flu-like symptoms. Two stopped: one nausea, one abnormal liver function (stealosis on biopsy). Leucopenia occurred in two cases and resolved with minor dose reductions.. Allopurinol co-therapy with low-dose AZA/MP can alleviate thiopurine hepatotoxicity. It appears safe and effective for long-term use, but requires monitoring for myelotoxicity. Assessing the TPMT activity helps tailor the AZA/MP doses.

Topics: Adult; Aged; Allopurinol; Chemical and Drug Induced Liver Injury; Dose-Response Relationship, Drug; Drug Synergism; Drug Therapy, Combination; Drug-Related Side Effects and Adverse Reactions; Enzyme Inhibitors; Female; Humans; Immunosuppressive Agents; Inflammatory Bowel Diseases; Male; Mercaptopurine; Methyltransferases; Middle Aged; Retrospective Studies; Treatment Outcome

Topics: Drug-Related Side Effects and Adverse Reactions; Humans; Mercaptopurine; Methyltransferases; Polymorphism, Single Nucleotide; Thioguanine

The FDA's Spontaneous Reporting System (SRS) database contains over 1.5 million adverse drug reaction (ADR) reports for 8620 drugs/biologics that are listed for 1191 Coding Symbols for Thesaurus of Adverse Reaction (COSTAR) terms of adverse effects. We have linked the trade names of the drugs to 1861 generic names and retrieved molecular structures for each chemical to obtain a set of 1515 organic chemicals that are suitable for modeling with commercially available QSAR software packages. ADR report data for 631 of these compounds were extracted and pooled for the first five years that each drug was marketed. Patient exposure was estimated during this period using pharmaceutical shipping units obtained from IMS Health. Significant drug effects were identified using a Reporting Index (RI), where RI = (# ADR reports / # shipping units) x 1,000,000. MCASE/MC4PC software was used to identify the optimal conditions for defining a significant adverse effect finding. Results suggest that a significant effect in our database is characterized by > or = 4 ADR reports and > or = 20,000 shipping units during five years of marketing, and an RI > or = 4.0. Furthermore, for a test chemical to be evaluated as active it must contain a statistically significant molecular structural alert, called a decision alert, in two or more toxicologically related endpoints. We also report the use of a composite module, which pools observations from two or more toxicologically related COSTAR term endpoints to provide signal enhancement for detecting adverse effects.

Topics: Adverse Drug Reaction Reporting Systems; Artificial Intelligence; Computers; Databases, Factual; Drug Prescriptions; Drug-Related Side Effects and Adverse Reactions; Endpoint Determination; Models, Molecular; Quantitative Structure-Activity Relationship; Software; United States; United States Food and Drug Administration

Topics: Antimetabolites; Biomedical Research; Drug-Related Side Effects and Adverse Reactions; Humans; Hydroxymethylglutaryl CoA Reductases; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Mercaptopurine; Methyltransferases; Pharmaceutical Preparations; Pharmacogenetics; Thioguanine

The analysis of the total of 76 occupational dermatoses registered after 1962 in the pharmaceutical industry of the district of Dresden results in the following statements: The morbidity must be regarded as three times higher than in other branches of the chemical industry. Compared with the average dates of all occupational dermatoses, those in the pharmaceutical industry need a shorter induction time for starting. On the other hand, they are to be cured faster and with less recurrences. The lists of causal agents are heterogeneous and differ largely from those of drug induced eczemas of our clinical patients or of employees in public health services. Examples are given for a predictive recognizing of strong contact sensitizers by means of their chemical structure.

Topics: Acetonitriles; Benzenesulfonates; Chemical Phenomena; Chemistry; Dermatitis, Occupational; Drug Industry; Drug-Related Side Effects and Adverse Reactions; Germany, East; Humans; Mercaptopurine

Topics: Age Factors; Asparaginase; Chickenpox; Child, Preschool; Counseling; Cyclophosphamide; Cytarabine; Cytomegalovirus Infections; Daunorubicin; Drug-Related Side Effects and Adverse Reactions; Humans; Injections, Spinal; Leukemia; Mercaptopurine; Methotrexate; Patient Care Planning; Pediatrics; Physician-Patient Relations; Prednisone; Prognosis; Sex Factors; Vincristine

Topics: Animals; Busulfan; Chlorambucil; Cyclophosphamide; Dactinomycin; Drug-Related Side Effects and Adverse Reactions; Folic Acid Antagonists; Haplorhini; Hematologic Diseases; Hematopoiesis; Infections; Leukocyte Count; Leukopenia; Mechlorethamine; Mercaptopurine; Models, Biological; Pyrimidines; Thiotepa; Triethylenemelamine; Vinblastine; Vincristine

Topics: Anemia, Myelophthisic; Child; Drug-Related Side Effects and Adverse Reactions; Humans; Mercaptopurine

Topics: Anemia, Myelophthisic; Bone Marrow; Drug-Related Side Effects and Adverse Reactions; Humans; Mercaptopurine; Regeneration