A Prediction Model for Successful Increase of Adalimumab Dose Intervals in Patients with Crohn's Disease: Secondary Analysis of the Pragmatic Open-Label Randomised Controlled Non-inferiority LADI Trial.

BACKGROUND: In the pragmatic open-label randomised controlled non-inferiority LADI trial we showed that increasing adalimumab (ADA) dose intervals was non-inferior to conventional dosing for persistent flares in patients with Crohn's disease (CD) in clinical and biochemical remission. AIMS: To develop a prediction model to identify patients who can successfully increase their ADA dose interval based on secondary analysis of trial data. METHODS: Patients in the intervention group of the LADI trial increased ADA intervals to 3 and then to 4 weeks. The dose interval increase was defined as successful when patients had no persistent flare (> 8 weeks), no intervention-related severe adverse events, no rescue medication use during the study, and were on an increased dose interval while in clinical and biochemical remission at week 48. Prediction models were based on logistic regression with relaxed LASSO. Models were internally validated using bootstrap optimism correction. RESULTS: We included 109 patients, of which 60.6% successfully increased their dose interval. Patients that were active smokers (odds ratio [OR] 0.90), had previous CD-related intra-abdominal surgeries (OR 0.85), proximal small bowel disease (OR 0.92), an increased Harvey-Bradshaw Index (OR 0.99) or increased faecal calprotectin (OR 0.997) were less likely to successfully increase their dose interval. The model had fair discriminative ability (AUC = 0.63) and net benefit analysis showed that the model could be used to select patients who could increase their dose interval. CONCLUSION: The final prediction model seems promising to select patients who could successfully increase their ADA dose interval. The model should be validated externally before it may be applied in clinical practice. CLINICAL TRIAL REGISTRATION NUMBER: ClinicalTrials.gov, number NCT03172377.

Neovaginal cancer after sigmoid vaginoplasty: Implications for postoperative cancer surveillance.

Background: Intestinal vaginoplasty can be performed as vaginal reconstruction procedure. Aa pedicled intestinal segment is isolated and transferred to the (neo)vaginal cavity to form the neovaginal lining. Case: A 38-year old patient with Fanconi anemia and congenital vaginal absence, who underwent sigmoid vaginoplasty at the age of one, visited the outpatient clinic with a palpable neovaginal mass. At MRI examination, a neovaginal tumor was observed of approximately 25 × 10 mm without lymphadenopathy, which turned out to be a mucinous adenocarcinoma (T3N0M0). She underwent excision of the total mesocolon, including the sigmoid neovagina, coloanal anastomosis and anus. Summary and Conclusion: Postoperative cancer surveillance seems justified after sigmoid vaginoplasty, even more so in patients with a (genetically) high risk of developing cancer and/or with a history of malignancy.

Exploring the role of oxidative stress and the effect of N-acetylcysteine in thiopurine-induced liver injury in inflammatory bowel disease: A randomized crossover pilot study.

Thiopurine treatment is regularly complicated by drug-induced liver injury. It has been suggested that oxidative stress may play a synergistic role. To assess whether thiopurine-induced liver injury coincides with increased oxidative stress and whether co-administration with N-acetylcysteine is protective, we performed a randomized open label crossover pilot study in inflammatory bowel disease patients with thiopurine-induced increased serum liver tests. The study comprised four stages of 4 weeks. Patients received no additional therapy followed by N-acetylcysteine 1200 mg twice a day, or the other way around, alongside ongoing thiopurine treatment. The third and fourth stages comprised a washout period and thiopurine reintroduction period. Nine patients completed the study, and the addition of N-acetylcysteine decreased myeloperoxidase concentrations (33.6-24.5 pmol/L, p = 0.038). The other biomarkers remained unchanged, including thiopurine metabolites, xanthine oxidase activity, thiopurine S-methyltransferase activity and serum liver enzyme activity tests. Reintroduction of thiopurines led to an increase of F2-isoprostanes (101-157 ng/mmol, p = 0.038), but not of serum liver enzyme activity tests. Results suggests that thiopurines may increase oxidative stress and although the addition of N-acetylcysteine led to a decrease in plasma myeloperoxidase concentrations, it does not protect from thiopurine-induced increase of serum liver tests.

Implications of Tioguanine Dosing in IBD Patients with a TPMT Deficiency.

Tioguanine is metabolised by fewer enzymatic steps compared to azathioprine and mercaptopurine, without generating 6-methylmercaptopurine ribonucleotides. However, thiopurine S-methyl transferase (TPMT) plays a role in early toxicity in all thiopurines. We aimed to describe the hazards and opportunities of tioguanine use in inflammatory bowel disease (IBD) patients with aberrant TPMT metabolism and propose preventative measures to safely prescribe tioguanine in these patients. In this retrospective cohort study, all determined TPMT genotypes (2016-2021) were evaluated for aberrant metabolism (i.e., intermediate and poor TPMT metabolisers). Subsequently, all IBD patients on tioguanine with aberrant TPMT genotypes were evaluated for tioguanine dosages, adverse drug events, lab abnormalities, treatment duration and effectiveness. TPMT genotypes were determined in 485 patients, of whom, 50 (10.3%) and 4 patients (0.8%) were intermediate and poor metabolisers, respectively. Of these patients, 12 intermediate and 4 poor TPMT metabolisers had been prescribed tioguanine in varying doses. In one poor TPMT metaboliser, tioguanine 10 mg/day induced delayed pancytopenia. In general, reduced tioguanine dosages of 5 mg/day for intermediate TPMT metabolisers, and 10 mg two-weekly for poor TPMT metabolisers, resulted in a safe, long-term treatment strategy. Diminished or absent TPMT enzyme activity was related with a pharmacokinetic shift of tioguanine metabolism which is associated with relatively late-occurring myelotoxicity in patients on standard tioguanine dose. However, in strongly reduced dose regimens with strict therapeutic drug and safety monitoring, tioguanine treatment remained a safe and effective option in IBD patients with dysfunctional TPMT.

Cost-Effectiveness Analysis of Increased Adalimumab Dose Intervals in Crohn's Disease Patients in Stable Remission: The Randomized Controlled LADI Trial.

BACKGROUND AND AIMS: We aimed to assess cost-effectiveness of increasing adalimumab dose intervals compared to the conventional dosing interval in patients with Crohn's disease [CD] in stable clinical and biochemical remission. DESIGN: We conducted a pragmatic, open-label, randomized controlled non-inferiority trial, comparing increased adalimumab intervals with the 2-weekly interval in adult CD patients in clinical remission. Quality of life was measured with the EQ-5D-5L. Costs were measured from a societal perspective. Results are shown as differences and incremental net monetary benefit [iNMB] at relevant willingness to accept [WTA] levels. RESULTS: We randomized 174 patients to the intervention [n = 113] and control [n = 61] groups. No difference was found in utility (difference: -0.017, 95% confidence interval [-0.044; 0.004]) and total costs (-€943, [-€2226; €1367]) over the 48-week study period between the two groups. Medication costs per patient were lower (-€2545, [-€2780; -€2192]) in the intervention group, but non-medication healthcare (+€474, [+€149; +€952]) and patient costs (+€365 [+€92; €1058]) were higher. Cost-utility analysis showed that the iNMB was €594 [-€2099; €2050], €69 [-€2908; €1965] and -€455 [-€4,096; €1984] at WTA levels of €20 000, €50 000 and €80 000, respectively. Increasing adalimumab dose intervals was more likely to be cost-effective at WTA levels below €53 960 per quality-adjusted life year. Above €53 960 continuing the conventional dose interval was more likely to be cost-effective. CONCLUSION: When the loss of a quality-adjusted life year is valued at less than €53 960, increasing the adalimumab dose interval is a cost-effective strategy in CD patients in stable clinical and biochemical remission. CLINICAL TRIAL REGISTRATION NUMBER: ClinicalTrials.gov, number NCT03172377.

Therapeutic Drug Monitoring of Vedolizumab in Inflammatory Bowel Disease Patients during Maintenance Treatment-TUMMY Study.

There are limited data on therapeutic drug monitoring (TDM) in inflammatory bowel disease (IBD) patients treated with vedolizumab (VDZ). Although an exposure-response relation has been demonstrated in the post-induction phase, this relationship is more uncertain in the maintenance phase of treatment. The aim of our study was to determine whether there is an association between VDZ trough concentration and clinical and biochemical remission in the maintenance phase. A prospective, observational multicenter study has been performed on patients with IBD on VDZ in the maintenance treatment (≥14 weeks). Patient demographics, biomarkers, and VDZ serum trough concentrations were collected. Clinical disease activity was scored by the Harvey Bradshaw Index (HBI) for Crohn's disease (CD) and the Simple Clinical Colitis Activity Index (SCCAI) for ulcerative colitis (UC). Clinical remission was determined as HBI < 5 and SCCAI < 3. Biochemical remission was defined as fecal calprotectin <250 mg/kg and serum CRP <5 mg/L. A total of 159 patients (59 CD, 100 UC) were included. In none of the patient groups, a statistically significant correlation between trough VDZ concentration and clinical remission was observed. Patients in biochemical remission had higher VDZ trough concentrations (p = 0.019). In this population, higher trough VDZ concentrations were associated with biochemical remission but not with clinical remission.

A Systematic Review on Long-Term Efficacy Outcome Measures in Crohn's Disease Patients.

BACKGROUND: The traditional long-term treatment goal of Crohn's disease [CD] is maintenance of corticosteroid-free clinical remission. Additional treatment targets, such as biochemical, endoscopic and patient-reported remission, are advocated. The relapsing-remitting nature of CD provides a challenge to the timing of target assessment. Cross-sectional assessment at predetermined moments disregards the health state in between measurements. In this systematic review, we provide an overview of outcomes used to assess long-term efficacy in clinical trials in CD. METHODS: A systematic search of the PubMed and EMBASE databases was performed to identify clinical trials in luminal CD reporting on maintenance treatment [strategies] since 1995. Two independent reviewers selected eligible articles for full text retrieval, and assessed if long-term corticosteroid-free clinical, biochemical, endoscopic or patient-reported efficacy outcomes were used. RESULTS: The search resulted in 2452 hits and 82 articles were included. Clinical activity was used in 80 studies [98%] as the long-term efficacy outcome, and in 21 [26%] of these concomitant corticosteroid use was taken into account. C-reactive protein was used in 32 studies [41%], faecal calprotectin in 15 studies [18%], endoscopic activity in 34 studies [41%] and patient-reported outcome in 32 studies [39%]. In seven studies, clinical, biochemical, endoscopic activity and the patient's perspective were measured. In most studies cross-sectional measures or multiple measurements over time were used. CONCLUSION: In none of the published clinical trials in CD was sustained remission on all treatment targets reported. Cross-sectional outcomes at predetermined times were widely applied, leading to lack of information regarding sustained corticosteroid-free remission for this relapsing-remitting chronic disease.

Development and Validation of a Remote Monitoring Tool for Assessment of Mild, Moderate, and Severe Infections in Inflammatory Bowel Disease.

BACKGROUND: Immunomodulators and biologics are cornerstones in the management of inflammatory bowel disease [IBD], but are associated with increased risk of infections. Post-marketing surveillance registries are pivotal to assess this risk, yet mainly focus on severe infections. Data on the prevalence of mild and moderate infections are scarce. We developed and validated a remote monitoring tool for real-world assessment of infections in IBD patients. METHODS: A 7-item Patient-Reported Infections Questionnaire [PRIQ] covering 15 infection categories was developed with a 3-month recall period. Infection severity was defined as mild [self-limiting or topical treatment], moderate [oral antibiotics, antivirals, or antifungals], or severe [hospitalisation or intravenous treatment]. Comprehensiveness and comprehensibility were ascertained through cognitive interviewing of 36 IBD outpatients. After implementation in the telemedicine platform myIBDcoach, a prospective, multicentre cohort study was performed between June 2020 and June 2021 in 584 patients, to assess diagnostic accuracy. Events were cross-checked with general practitioner and pharmacy data [gold standard]. Agreement was evaluated using linear-weighted kappa with cluster-bootstrapping to account for within-patient level correlation. RESULTS: Patient understanding was good and interviews did not result in reduction of PRIQ items. During validation, 584 IBD patients {57.8% female, mean age 48.6 (standard deviaton [SD]: 14.8), disease duration 12.6 years [SD: 10.9]} completed 1386 periodic assessments, reporting 1626 events. Linear-weighted kappa for agreement between PRIQ and gold standard was 0.92 (95% confidence interval [CI] 0.89-0.94). Sensitivity and specificity for infection [yes/no] were 93.9% [95% CI 91.8-96.0] and 98.5% [95% CI 97.5-99.4], respectively. CONCLUSIONS: The PRIQ is a valid and accurate remote monitoring tool to assess infections in IBD patients, providing means to personalise medicine based on adequate benefit-risk assessments.

Increased versus conventional adalimumab dose interval for patients with Crohn's disease in stable remission (LADI): a pragmatic, open-label, non-inferiority, randomised controlled trial.

BACKGROUND: Despite its effectiveness in treating Crohn's disease, adalimumab is associated with an increased risk of infections and high health-care costs. We aimed to assess clinical outcomes of increased adalimumab dose intervals versus conventional dosing in patients with Crohn's disease in stable remission. METHODS: The LADI study was a pragmatic, open-label, multicentre, non-inferiority, parallel, randomised controlled trial, done in six academic hospitals and 14 general hospitals in the Netherlands. Adults (aged ≥18 years) diagnosed with luminal Crohn's disease (with or without concomitant perianal disease) were eligible when in steroid-free clinical and biochemical remission (defined as Harvey-Bradshaw Index [HBI] score <5, faecal calprotectin <150 µg/g, and C-reactive protein <10 mg/L) for at least 9 months on a stable dose of 40 mg subcutaneous adalimumab every 2 weeks. Patients were randomly assigned (2:1) to the intervention group or control group by the coordinating investigator using a secure web-based system with variable block randomisation (block sizes of 6, 9, and 12). Randomisation was stratified on concomitant use of thiopurines and methotrexate. Patients and health-care providers were not masked to group assignment. Patients allocated to the intervention group increased adalimumab dose intervals to 40 mg every 3 weeks at baseline and further to every 4 weeks if they remained in clinical and biochemical remission at week 24. Patients in the control group continued their 2-weekly dose interval. The primary outcome was the cumulative incidence of persistent flares at week 48 defined as the presence of at least two of the following criteria: HBI score of 5 or more, C-reactive protein 10 mg/L or more, and faecal calprotectin more than 250 µg/g for more than 8 weeks and a concurrent decrease in the adalimumab dose interval or start of escape medication. The non-inferiority margin was 15% on a risk difference scale. All analyses were done in the intention-to-treat and per-protocol populations. This trial was registered at ClinicalTrials.gov, NCT03172377, and is not recruiting. FINDINGS: Between May 3, 2017, and July 6, 2020, 174 patients were randomly assigned to the intervention group (n=113) or the control group (n=61). Four patients from the intervention group and one patient from the control group were excluded from the analysis for not meeting inclusion criteria. 85 (50%) of 169 participants were female and 84 (50%) were male. At week 48, the cumulative incidence of persistent flares in the intervention group (three [3%] of 109) was non-inferior compared with the control group (zero; pooled adjusted risk difference 1·86% [90% CI -0·35 to 4·07). Seven serious adverse events occurred, all in the intervention group, of which two (both patients with intestinal obstruction) were possibly related to the intervention. Per 100 person-years, 168·35 total adverse events, 59·99 infection-related adverse events, and 42·57 gastrointestinal adverse events occurred in the intervention group versus 134·67, 75·03, and 5·77 in the control group, respectively. INTERPRETATION: The individual benefit of increasing adalimumab dose intervals versus the risk of disease recurrence is a trade-off that should take patient preferences regarding medication and the risk of a flare into account. FUNDING: Netherlands Organisation for Health Research and Development.

Thioguanine is Effective as Maintenance Therapy for Inflammatory Bowel Disease: A Prospective Multicentre Registry Study.

BACKGROUND AND AIMS: Thioguanine is a well-tolerated and effective therapy for inflammatory bowel disease [IBD] patients. Prospective effectiveness data are needed to substantiate the role of thioguanine as a maintenance therapy for IBD. METHODS: IBD patients who previously failed azathioprine or mercaptopurine and initiated thioguanine were prospectively followed for 12 months starting when corticosteroid-free clinical remission was achieved (Harvey-Bradshaw Index [HBI] ≤ 4 or Simple Clinical Colitis Activity Index [SCCAI] ≤ 2). The primary endpoint was corticosteroid-free clinical remission throughout 12 months. Loss of clinical remission was defined as SCCAI > 2 or HBI > 4, need of surgery, escalation of therapy, initiation of corticosteroids or study discontinuation. Additional endpoints were adverse events, drug survival, physician global assessment [PGA] and quality of life [QoL]. RESULTS: Sustained corticosteroid-free clinical remission at 3, 6 or 12 months was observed in 75 [69%], 66 [61%] and 49 [45%] of 108 patients, respectively. Thioguanine was continued in 86 patients [80%] for at least 12 months. Loss of response [55%] included escalation to biologicals in 15%, corticosteroids in 10% and surgery in 3%. According to PGA scores, 82% of patients were still in remission after 12 months and QoL scores remained stable. Adverse events leading to discontinuation were reported in 11%, infections in 10%, myelo- and hepatotoxicity each in 6%, and portal hypertension in 1% of patients. CONCLUSION: Sustained corticosteroid-free clinical remission over 12 months was achieved in 45% of IBD patients on monotherapy with thioguanine. A drug continuation rate of 80%, together with favourable PGA and QoL scores, underlines the tolerability and effectiveness of thioguanine for IBD.

Superior Effectiveness of Tofacitinib Compared to Vedolizumab in Anti-TNF-experienced Ulcerative Colitis Patients: A Nationwide Dutch Registry Study.

BACKGROUND & AIMS: Clinicians face difficulty in when and in what order to position biologics and Janus kinase inhibitors in patients with anti-tumor necrosis factor-alpha (TNF) refractory ulcerative colitis (UC). We aimed to compare the effectiveness and safety of vedolizumab and tofacitinib in anti-TNF-exposed patients with UC in our prospective nationwide Initiative on Crohn and Colitis Registry. METHODS: Patients with UC who failed anti-TNF treatment and initiated vedolizumab or tofacitinib treatment were identified in the Initiative on Crohn and Colitis Registry in the Netherlands. We selected patients with both clinical as well as biochemical or endoscopic disease activity at initiation of therapy. Patients previously treated with vedolizumab or tofacitinib were excluded. Corticosteroid-free clinical remission (Simple Clinical Colitis Activity Index ≤2), biochemical remission (C-reactive protein ≤5 mg/L or fecal calprotectin ≤250 µg/g), and safety outcomes were compared after 52 weeks of treatment. Inverse propensity score-weighted comparison was used to adjust for confounding and selection bias. RESULTS: Overall, 83 vedolizumab- and 65 tofacitinib-treated patients were included. Propensity score-weighted analysis showed that tofacitinib-treated patients were more likely to achieve corticosteroid-free clinical remission and biochemical remission at weeks 12, 24, and 52 compared with vedolizumab-treated patients (odds ratio [OR], 6.33; 95% confidence interval [CI], 3.81-10.50; P < .01; OR, 3.02; 95% CI, 1.89-4.84; P < .01; and OR, 1.86; 95% CI, 1.15-2.99; P = .01; and OR, 3.27; 95% CI, 1.96-5.45; P < .01; OR, 1.87; 95% CI, 1.14-3.07; P = .01; and OR, 1.81; 95% CI, 1.06-3.09; P = .03, respectively). There was no difference in infection rate or severe adverse events. CONCLUSIONS: Tofacitinib was associated with superior effectiveness outcomes compared with vedolizumab in anti-TNF-experienced patients with UC along with comparable safety outcomes.

Anemia and Iron Deficiency in Outpatients with Inflammatory Bowel Disease: Ubiquitous Yet Suboptimally Managed.

Background: Iron deficiency (ID) and anemia in patients with Inflammatory Bowel Disease (IBD) are associated with a reduced quality of life. We assessed the prevalence of ID and anemia in Dutch outpatients with IBD and compared routine ID(A) management among medical professionals to the European Crohn's and Colitis Organisation (ECCO) treatment guidelines. Methods: Between January and November 2021, consecutive adult outpatients with IBD were included in this study across 16 Dutch hospitals. Clinical and biochemical data were extracted from medical records. Additionally, medical professionals filled out questionnaires regarding routine ID(A) management. Results: In total, 2197 patients (1271 Crohn's Disease, 849 Ulcerative Colitis, and 77 IBD-unclassified) were included. Iron parameters were available in 59.3% of cases. The overall prevalence of anemia, ID, and IDA was: 18.0%, 43.4%, and 12.2%, respectively. The prevalence of all three conditions did not differ between IBD subtypes. ID(A) was observed more frequently in patients with biochemically active IBD than in quiescent IBD (ID: 70.8% versus 23.9%; p < 0.001). Contrary to the guidelines, most respondents prescribed standard doses of intravenous or oral iron regardless of biochemical parameters or inflammation. Lastly, 25% of respondents reported not treating non-anemic ID. Conclusions: One in five patients with IBD suffers from anemia that­despite inconsistently measured iron parameters­is primarily caused by ID. Most medical professionals treat IDA with oral iron or standard doses of intravenous iron regardless of biochemical inflammation; however, non-anemic ID is often overlooked. Raising awareness about the management of ID(A) is needed to optimize and personalize routine care.

Predictive Algorithm for Thiopurine-Induced Hepatotoxicity in Inflammatory Bowel Disease Patients.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

A report on the potential of Rac1/pSTAT3 protein levels in T lymphocytes to assess the pharmacodynamic effect of thiopurine therapy in Inflammatory Bowel Disease patients.

The thiopurine derivatives azathioprine (AZA), mercaptopurine (MP) and tioguanine (TG) remain standard treatment of inflammatory bowel disease (IBD). The immune suppressive effect of thiopurines is primarily based on blocking the Ras-related C3 botulinum toxin substrate 1 (Rac1) causing apoptosis of T lymphocytes by inhibition of the phosphorylated downstream transcription factor Signal Transducer and Activator of Transcription 3 (pSTAT3). A functional pharmacodynamic marker in T lymphocytes may be useful to predict therapeutic outcome of thiopurine therapy. The aim of this study was to explore whether protein levels of Rac1 and pSTAT3 in T lymphocytes may be applied as a specific pharmacodynamic marker for thiopurine therapy in IBD patients. Rac1 and pSTAT3 protein levels in T lymphocytes were explored in 57 IBD patients (median age 51 years, 56% female), subdivided into six groups based on IBD activity and its treatment: patients with active disease without IBD maintenance medication (1) or patients in remission on AZA/MP (2), TG (3), infliximab (IFX) (4), thiopurine and IFX combination-treatment (5) or without IBD medication (6). Reference values were obtained from healthy subjects. Rac1 and pSTAT3 protein levels in T lymphocytes from patients on thiopurine monotherapy (group 2 and 3) were compared to the other groups, and to healthy subjects. Absolute Rac1 and pSTAT3 protein levels showed no differences between the thiopurine monotherapy groups when compared to patients with active disease. However, the ratio of Rac1 and pSTAT3 protein levels was lower in thiopurine patients groups compared to patients with active disease. Rac1-corrected pSTAT3 protein levels may serve as a pharmacodynamic marker of thiopurine monotherapy and may be a potential tool to predict therapeutic effectiveness in IBD patients.

Rac1/pSTAT3 expression: A pharmacodynamic marker panel as a first step toward optimization of thiopurine therapy in inflammatory bowel disease patients.

Thiopurine derivatives, such as azathioprine and mercaptopurine, are standard conventional treatment options in inflammatory bowel disease (IBD). Unfortunately, approximately half of patients discontinue thiopurine therapy within 2 years. To improve the prediction of clinical effectiveness, thiopurine therapy is currently optimized using therapeutic drug monitoring. Ras-related C3 botulinum toxin substrate 1 (Rac1) has been suggested as a potential pharmacodynamic marker of the thiopurine effect in lymphocytes. The active thiopurine metabolite 6-thioguanine triphosphate (6-Thio-GTP) causes T cell apoptosis via Rac1 and the downstream transcription factor signal transducer and activator of transcription 3 (STAT3). The aim of this study was to develop and validate a functional pharmacodynamic multiparameter flow cytometric assay to determine Rac1/pSTAT3 expression in the various leukocyte subpopulations in peripheral blood in order to predict therapeutic response in IBD patients in the future. Peripheral blood samples of healthy subjects (no fever or clinical complaints of active disease, C-reactive protein < 10 mg/L) were used for immunocytochemical labeling, applying an optimized fixation and permeabilization strategy. A gating procedure was performed to separate all leukocyte subpopulations. Quantitative data were obtained by measuring presence and median fluorescent intensity. In vitro, Rac1 presence and expression were detectable in all leukocyte subpopulations. After IL-6 stimulation, used as proxy for inflammation, a distinct pSTAT3 signal could be detected in T lymphocytes of healthy subjects. In vivo, an upregulated pSTAT3 signal was detected in nearly all IBD patients with active disease and differed substantially from the signal found in IBD patients in remission on thiopurines and healthy subjects. We developed and validated a functional flow cytometric assay to assess Rac1 and pSTAT3 presence and expression. This opens a venue for a pharmacodynamic assay to predict thiopurine effectiveness in IBD patients.

Replacement of Nitrite in Meat Products by Natural Bioactive Compounds Results in Reduced Exposure to N-Nitroso Compounds: The PHYTOME Project.

SCOPE: It has been proposed that endogenously form N-nitroso compounds (NOCs) are partly responsible for the link between red meat consumption and colorectal cancer (CRC) risk. As nitrite has been indicated as critical factor in the formation of NOCs, the impact of replacing the additive sodium nitrite (E250) by botanical extracts in the PHYTOME project is evaluated. METHOD AND RESULTS: A human dietary intervention study is conducted in which healthy subjects consume 300 g of meat for 2 weeks, in subsequent order: conventional processed red meat, white meat, and processed red meat with standard or reduced levels of nitrite and added phytochemicals. Consumption of red meat products enriched with phytochemicals leads to a significant reduction in the faecal excretion of NOCs, as compared to traditionally processed red meat products. Gene expression changes identify cell proliferation as main affects molecular mechanism. High nitrate levels in drinking water in combination with processed red meat intake further stimulates NOC formation, an effect that could be mitigated by replacement of E250 by natural plant extracts. CONCLUSION: These findings suggest that addition of natural extracts to conventionally processed red meat products may help to reduce CRC risk, which is mechanistically support by gene expression analyses.

Current status and future perspectives on the use of therapeutic drug monitoring of thiopurine metabolites in patients with inflammatory bowel disease.

INTRODUCTION: Despite new treatment options for inflammatory bowel disease (IBD), conventional thiopurines remain a common treatment option for maintaining remission, particularly in non-Westernized countries. Therapeutic drug monitoring (TDM) is advised in standard care for optimizing therapy strategies to improve effectiveness, reveal nonadherence, and reduce toxicity. Still, the rationale of TDM is debated. AREAS COVERED: Key insights on TDM of thiopurine metabolites are discussed. The pharmacology of thiopurines is described, emphasizing the interindividual differences in pharmacogenetics, pharmacokinetics, and pharmacodynamics. Pharmacological differences between conventional thiopurines and tioguanine are outlined. Finally, several optimization strategies for thiopurine therapy in IBD are discussed. EXPERT OPINION: TDM has been a useful, but limited, tool to individualize thiopurine therapy. Pharmacokinetic data on the active thiopurine metabolites, derived from measurements in erythrocytes, associated with clinical response only partially predict effectiveness and toxicity. An additional pharmacodynamic marker, such as Rac1/pSTAT3 expression in leukocytes, may improve applicability of TDM in the future.

Clinical Outcomes of Covid-19 in Patients With Inflammatory Bowel Disease: A Nationwide Cohort Study.

BACKGROUND AND AIMS: The COVID-19 risk and disease course in inflammatory bowel disease [IBD] patients remains uncertain. Therefore, we aimed to assess the clinical presentation, disease course, and outcomes of COVID-19 in IBD patients. Second, we determined COVID-19 incidences in IBD patients and compared this with the general population. METHODS: We conducted a multicentre, nationwide IBD cohort study in The Netherlands and identified patients with COVID-19. First, we assessed the COVID-19 disease course and outcomes. Second, we compared COVID-19 incidences between our IBD study cohort and the general Dutch population. RESULTS: We established an IBD cohort of 34 763 patients. COVID-19 was diagnosed in 100/34 763 patients [0.29%]; 20/100 of these patients [20%] had severe COVID-19 defined as admission to the intensive care unit, mechanical ventilation, and/or death. Hospitalisation occurred in 59/100 [59.0%] patients and 13/100 [13.0%] died. All patients who died had comorbidities and all but one were ≥65 years old. In line, we identified ≥1 comorbidity as an independent risk factor for hospitalisation (odds ratio [OR] 4.20, 95% confidence interval [CI] 1.58-11.17,; p = 0.004). Incidences of COVID-19 between the IBD study cohort and the general population were comparable (287.6 [95% CI 236.6-349.7] versus 333.0 [95% CI 329.3-336.7] per 100000 patients, respectively; p = 0.15). CONCLUSIONS: Of 100 cases with IBD and COVID-19, 20% developed severe COVID-19, 59% were hospitalised and 13% died. A comparable COVID-19 risk was found between the IBD cohort [100/34 763 = 0.29%] and the general Dutch population. The presence of ≥1 comorbidities was an independent risk factor for hospitalisation due to COVID-19.