Complete Endoscopic Healing Is Associated With Lower Relapse Risk After Anti-TNF Withdrawal in Inflammatory Bowel Disease.

BACKGROUND & AIMS: Discontinuation of anti-tumor necrosis factor-α treatment (anti-TNF) (infliximab and adalimumab) in patients with inflammatory bowel disease (IBD) is associated with a high relapse risk that may be influenced by endoscopic activity at the time of stopping. We assessed the relapse rate after anti-TNF withdrawal in patients with endoscopic healing and studied predictors of relapse including the depth of endoscopic healing. METHODS: This was a multicenter, prospective study in adult patients with Crohn's disease (CD), ulcerative colitis (UC), or IBD-unclassified (IBDU), with ≥6 months of corticosteroid-free clinical remission (confirmed at baseline) and endoscopic healing (Mayo <2/SES-CD <5 without large ulcers), who discontinued anti-TNF between 2018 and 2020 in the Netherlands. We performed Kaplan-Meier and Cox regression analyses to assess the relapse rate and evaluate potential predictors: partial (Mayo 1/SES-CD 3-4) versus complete (Mayo 0/SES-CD 0-2) endoscopic healing, anti-TNF trough levels, and immunomodulator and/or mesalamine use. RESULTS: Among 81 patients (CD: n = 41, 51%) with a median follow-up of 2.0 years (interquartile range, 1.6-2.1), 40 patients (49%) relapsed. Relapse rates in CD and UC/IBDU patients were comparable. At 12 months, 70% versus 35% of patients with partial versus complete endoscopic healing relapsed, respectively (adjusted hazard rate [aHR], 3.28; 95% confidence interval [CI], 1.43-7.50). Mesalamine use was associated with fewer relapses in UC/IBDU patients (aHR, 0.08; 95% CI, 0.01-0.67). Thirty patients restarted anti-TNF, and clinical remission was regained in 73% at 3 months. CONCLUSIONS: The relapse risk was high after anti-TNF withdrawal in IBD patients with endoscopic healing, but remission was regained in most cases after anti-TNF reintroduction. Complete endoscopic healing and mesalamine treatment in UC/IBDU patients decreased the risk of relapse.

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.

Immunomodulator Withdrawal From Anti-TNF Therapy Is Not Associated With Loss of Response in Inflammatory Bowel Disease.

BACKGROUND AND AIMS: The benefit of concomitant immunomodulators (thiopurines or methotrexate) in patients with inflammatory bowel disease (IBD) on anti-tumor necrosis factor α (anti-TNF) (infliximab or adalimumab) maintenance therapy is debated. We compared outcomes after immunomodulator withdrawal vs continuation of combination therapy. METHODS: This was a retrospective cohort study in a general hospital and a tertiary referral center. We included adult IBD patients, receiving anti-TNF therapy for ≥4 months, plus an immunomodulator at baseline, between January 1, 2011, and January 1, 2019. The primary endpoints were loss of response (LOR) (ie, anti-TNF discontinuation because of disease activity) and anti-drug antibodies. Adjusted hazard ratios (aHRs) were calculated by mixed-effects Cox regression analysis. RESULTS: We included 614 treatment episodes of combination therapy in 543 individuals, yielding 1664 patient-years of follow-up. The immunomodulator was withdrawn in 296 (48.2%) episodes after 0.9 (interquartile range, 0.6-2.1) years, which was not associated with a higher risk of LOR (aHR, 1.08; 95% confidence interval [CI], 0.72-1.61), although anti-drug antibodies were detected more frequently (aHR, 2.14; 95% CI, 1.17-3.94), compared with continuation. Clinical remission at the time of withdrawal reduced the risk of LOR (aHR, 0.48; 95% CI, 0.25-0.93), while longer duration of combination therapy before withdrawal decreased the risk of anti-drug antibodies (HR per year, 0.56; 95% CI, 0.32-0.91). Higher prewithdrawal infliximab trough levels reduced the subsequent risks of anti-drug antibodies and LOR. Infliximab trough levels were lower after immunomodulator withdrawal (P = .01). CONCLUSIONS: Patients who withdrew the immunomodulator in this retrospective cohort were not at increased risk of LOR within the following 1-2 years, but an increase in anti-drug antibodies was observed. Our findings require prospective validation, preferably in adequately powered randomized controlled trials.

Adherence to Adalimumab Was Not Improved by a Reminder-Based Intervention with an Electronic Needle Container.

BACKGROUND: Adherence to adalimumab in inflammatory bowel disease (IBD) patients is reported to be below par. Non-adherence may result in loss-of-response and increased hospitalization. We analyzed the effect of an electronic needle container (ENC) on adherence to adalimumab. METHODS: In this multicenter, 12-months observational study, we included adalimumab treated IBD patients. All patients were invited to receive an ENC. Patients who declined or did not complete the registration for an ENC served as controls. Primary endpoint was whether an ENC increased adherence, calculated from pharmacy refills as proportion of days covered (PDC). Secondary endpoints were clinical outcomes, including loss-of-response, identification of predictors of adherence and correlation between different modalities for measuring adherence. Loss-of-response was defined as a disease flare, dose-escalation or IBD-related hospitalization or surgery. RESULTS: The pharmacies' records identified 198 eligible patients, of whom 32 were excluded. The ENC was supplied to 69 patients, the remaining 97 patient formed the control group. Median baseline PDC (98.4% vs. 96.1%, p = 0.047) and the proportion of adherent (PDC ≥ 86%) patients (87.0% vs. 74.2%, p = 0.045) was higher for the ENC group. The ENC did not improve the adherence of patients during follow-up (odds ratio 1.26, 95% CI 0.55-2.86). During follow-up, five (7.2%) patients in the ENC group and 13 (13.4%) in the control group discontinued adalimumab (log-rank p = 0.22). Loss-of-response occurred in 12 (17.4%) and 14 (14.4%) patients, respectively (log-rank p = 0.66). CONCLUSIONS: Our results show no beneficial effect of a reminder-based intervention on adherence or treatment outcomes.

Infants born to mothers with IBD present with altered gut microbiome that transfers abnormalities of the adaptive immune system to germ-free mice.

BACKGROUND AND AIMS: Prenatal and early life bacterial colonisation is thought to play a major role in shaping the immune system. Furthermore, accumulating evidence links early life exposures to the risk of developing IBD later in life. We aimed to assess the effect of maternal IBD on the composition of the microbiome during pregnancy and on the offspring's microbiome. METHODS: We prospectively examined the diversity and taxonomy of the microbiome of pregnant women with and without IBD and their babies at multiple time points. We evaluated the role of maternal IBD diagnosis, the mode of delivery, antibiotic use and feeding behaviour on the microbiome composition during early life. To assess the effects of IBD-associated maternal and infant microbiota on the enteric immune system, we inoculated germ-free mice (GFM) with the respective stool and profiled adaptive and innate immune cell populations in the murine intestines. RESULTS: Pregnant women with IBD and their offspring presented with lower bacterial diversity and altered bacterial composition compared with control women and their babies. Maternal IBD was the main predictor of the microbiota diversity in the infant gut at 7, 14, 30, 60 and 90 days of life. Babies born to mothers with IBD demonstrated enrichment in Gammaproteobacteria and depletion in Bifidobacteria. Finally, GFM inoculated with third trimester IBD mother and 90-day infant stools showed significantly reduced microbial diversity and fewer class-switched memory B cells and regulatory T cells in the colon. CONCLUSION: Aberrant gut microbiota composition persists during pregnancy with IBD and alters the bacterial diversity and abundance in the infant stool. The dysbiotic microbiota triggered abnormal imprinting of the intestinal immune system in GFM.

Limited relevance and progression of histological alterations in the liver during thioguanine therapy in inflammatory bowel disease patients.

Background: Thioguanine is associated with liver toxicity, especially nodular regenerative hyperplasia (NRH). We assessed if liver histology alters during long-term maintenance treatment with thioguanine in patients with inflammatory bowel disease (IBD). Methods: Liver specimens of thioguanine treated IBD patients with at least two liver biopsies were revised by two independent liver pathologists, blinded to clinical characteristics. Alterations in histopathological findings between first and sequential liver specimen were evaluated and associated clinical data, including laboratory parameters and abdominal imaging reports, were collected. Results: Twenty-five IBD patients underwent sequential liver biopsies prior to, at time of, or after cessation of thioguanine treatment. The median time between the first and second biopsy was 25 months (range: 14-54). Except for one normal liver specimen, any degree of irregularities including inflammation, steatosis, fibrosis and some vascular disturbances were observed in the biopsies. The rates of perisinusoidal fibrosis (91%), sinusoidal dilatation (68%) and nodularity (18%) were the same in the first and second liver biopsies. A trend towards statistical significance was observed for phlebosclerosis (36% of the first vs. 68% of the second biopsies, p = .092). Presence of histopathological liver abnormalities was not associated with clinical outcomes. Furthermore, two patients in this cohort had portal hypertension in presence of phlebosclerosis. In another two patients, nodularity of the liver resolved upon thioguanine withdrawal. Conclusion: Vascular abnormalities of the liver were commonly observed in thioguanine treated IBD patients, although these were not progressive and remained of limited clinical relevance over time.

Thiopurines with low-dose allopurinol (ThiLDA)-a prospective clinical one-way crossover trial.

PURPOSE: Many patients with Crohn's disease (CD) and ulcerative colitis (UC) who have a high 6-methylmercaptopurine/6-thioguanine (6-MMP/6-TGN) ratio receive allopurinol 100 mg in addition to thiopurines to optimize metabolite concentrations. However, some patients do not tolerate allopurinol at this dosage. The aim of this study was to determine the intra-patient effect of reducing the allopurinol dosage from 100 to 50 mg, in terms of metabolite concentrations, enzyme activities, efficacy, and tolerability. METHODS: A prospective non-inferiority one-way crossover study was performed. CD and UC patients with stable disease using a thiopurine and allopurinol 100 mg were switched to 50 mg for 1 month. Primary outcomes were thiopurine metabolite concentrations. Secondary outcomes were enzyme activities of xanthine oxidase, thiopurine methyltransferase and hypoxanthine-guanine phosphoribosyltransferase, disease activity, and tolerability. RESULTS: Twenty-two patients were included. Treatment with allopurinol 50 mg compared with 100 mg resulted in a significant decrease in mean 6-TGN levels (761 to 625 pmol/8 × 108 RBC; p = 0.005) and a significant increase in mean 6-MMP levels (451 to 665 pmol/8 × 108 RBC; p = 0.01). However, the mean metabolite concentrations were still therapeutic. Enzyme activities, disease activity scores, and patient experiences did not alter significantly. Generally, UC patients were more positive about their improved treatment than CD patients. CONCLUSION: Combination therapy with 50 mg allopurinol led to a decrease of 6-TGN levels compared with 100 mg allopurinol. Disease activity, side effects, and patient experience, however, were similar between allopurinol 100 and 50 mg. UC patients seem to benefit and prefer lower doses whereas the contrary is seen in CD patients. TRIAL REGISTRATION: EudraCT trial registry - number 2016-001638-84.

Intrauterine exposure and pharmacology of conventional thiopurine therapy in pregnant patients with inflammatory bowel disease.

OBJECTIVE: Several studies have demonstrated a favourable safety profile for thiopurine use for inflammatory bowel disease (IBD) during pregnancy. We performed a study in pregnant patients with IBD who were using thiopurines, in order to determine the influence of pregnancy on thiopurine metabolism and to assess intrauterine exposure of the fetus to thiopurines. DESIGN: Female patients with IBD receiving steady-state thiopurines and planning a pregnancy were prospectively enrolled. 6-Thioguanine nucleotide (6-TGN) and 6-methylmercaptopurine (6-MMP) concentrations were determined, combined with routine laboratory tests, before, during and after pregnancy. Thiopurine metabolites were measured in umbilical cord blood immediately after delivery. RESULTS: Thirty patients who were using azathioprine (28 patients, median dose 1.93 mg/kg) or mercaptopurine (two patients, doses 1.32 and 0.94 mg/kg) were included. During pregnancy, median 6-TGN decreased over time (p=0.001). while 6-MMP increased, without causing myelotoxicity or hepatotoxicity. After delivery, both 6-TGN and 6-MMP levels returned to preconception baseline levels. Fetal 6-TGN concentrations correlated positively with maternal 6-TGN levels (p<0.0001). No 6-MMP was detected in the newborns, except one born with pancytopenia and high alkaline phosphatase activity; the mother of this infant had severe pre-eclampsia. All infants had normal Apgar scores, but 60% had anaemia at birth. No major congenital abnormalities were observed. CONCLUSIONS: Pregnancy has a major effect on maternal thiopurine metabolism. In utero the unborn child is exposed to 6-TGN, but not to 6-MMP. Sixty per cent of the infants were born with anaemia, which raises the question whether infants should be tested for possible anaemia immediately after birth.

Multicentre study and systematic review: Allopurinol exposure during pregnancy.

BACKGROUND: Data about the safety of allopurinol in pregnant women are sparsely reported. AIMS: To investigate the risk of adverse pregnancy outcome and congenital abnormalities after in utero exposure to allopurinol in inflammatory bowel disease (IBD) pregnancies and in general. METHODS: We collected safety data of patients with IBD who were treated with allopurinol during pregnancy between January 2013 and March 2022. Additionally, we performed a systematic review about the teratogenic potential of allopurinol. RESULTS: We collected data from 42 allopurinol-exposed pregnancies, including one twin pregnancy; in all women, allopurinol was combined with a thiopurine. Six pregnancies (14.3%) resulted in miscarriage and one in stillbirth at 32 weeks. A congenital anomaly was observed in one newborn (coarctation of the aorta discovered postpartum). Three pregnancies, including the twin pregnancy, ended in moderate preterm delivery and one in very preterm delivery. Five neonates (15.2%) were small for gestational age. From our literature search, we identified an additional 102 allopurinol-exposed pregnancies resulting in 129 live births, including 36 infants from our cohort. Ten infants (7.8%) were born with a congenital anomaly. Two (1.6%) had a comparable pattern of multiple anomalies. The systematic review sub-analysis including only infants born to mothers with IBD (n = 76) revealed that 2.6% of infants had congenital anomalies after in utero exposure to a low dose of allopurinol. CONCLUSIONS: Overall, the teratogenicity of allopurinol remains inconclusive. Children conceived by mothers treated for IBD with allopurinol/thiopurine co-therapy do not seem to have an increased risk of congenital anomalies.

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.

Prophylactic Medication for the Prevention of Endoscopic Recurrence in Crohn's Disease: a Prospective Study Based on Clinical Risk Stratification.

BACKGROUND: To prevent recurrence after ileocolonic resection [ICR] in Crohn's disease [CD], postoperative prophylaxis based on risk stratification is recommended in international guidelines. This study aimed to evaluate postoperative CD recurrence after implementation of a clinical management algorithm and to determine the predictive value of clinical and histological risk factors [RFs]. METHODS: In this multicentre, prospective cohort study, CD patients [≥16 years] scheduled for ICR were included. The algorithm advised no postoperative medication for low-risk patients, and treatment with prophylaxis [immunosuppressant/biological] for high-risk patients [≥1 RF: active smoking, penetrating disease, prior ICR]. Clinical and histological RFs [active inflammation, granulomas, plexitis in resection margins] for endoscopic recurrence [Rutgeerts' score ≥i2b at 6 months] were assessed using logistic regression and ROC curves based on predicted probabilities. RESULTS: In total, 213 CD patients after ICR were included [age 34.5 years; 65% women] (93 [44%] low-risk; 120 [56%] high-risk: 45 [38%] smoking; 51 [43%] penetrating disease; 51 [43%] prior ICR). Adherence to the algorithm was 82% in low-risk [no prophylaxis] and 51% in high-risk patients [prophylaxis]. Endoscopic recurrence was higher in patients treated without prophylaxis than with prophylaxis in both low [45% vs 16%, p = 0.012] and high-risk patients [49% vs 26%, p = 0.019]. Clinical risk stratification including the prescription of prophylaxis corresponded to an area under the curve [AUC] of 0.70 (95% confidence interval [CI] 0.61-0.79). Clinical RFs combined with histological RFs increased the AUC to 0.73 [95% CI 0.64-0.81]. CONCLUSION: Adherence to this management algorithm is 65%. Prophylactic medication after ICR prevents endoscopic recurrence in low- and high-risk patients. Clinical risk stratification has an acceptable predictive value, but further refinement is needed.

Exposure to Thioguanine During 117 Pregnancies in Women With Inflammatory Bowel Disease.

BACKGROUND: Safety of thioguanine in pregnant patients with inflammatory bowel disease [IBD] is sparsely recorded. This study was aimed to document the safety of thioguanine during pregnancy and birth. METHODS: In this multicentre case series, IBD patients treated with thioguanine during pregnancy were included. Data regarding disease and medication history, pregnancy course, obstetric complications, and neonatal outcomes were collected. RESULTS: Data on 117 thioguanine-exposed pregnancies in 99 women were collected. Most [78%] had Crohn's disease and the mean age at delivery was 31 years. In 18 pregnancies [15%], IBD flared. Obstetric and infectious complications were seen in 15% [n = 17] and 7% [n = 8] of pregnancies, respectively. Ten pregnancies [8.5%] resulted in a first trimester miscarriage, one in a stillbirth at 22 weeks of gestational age and one in an induced abortion due to trisomy 21. In total, 109 neonates were born from 101 singleton pregnancies and four twin pregnancies. One child was born with a congenital abnormality [cleft palate]. In the singleton pregnancies, 10 children were born prematurely and 10 were born small for gestational age. Screening for myelosuppresion was performed in 16 neonates [14.7%]; two had anaemia in umbilical cord blood. All outcomes were comparable to either the general Dutch population or to data from three Dutch cohort studies on the use of conventional thiopurines in pregnant IBD patients. CONCLUSION: In this large case series, the use of thioguanine during pregnancy is not associated in excess with adverse maternal or neonatal 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.

Safety and efficacy of the immunosuppressive agent 6-tioguanine in murine model of acute and chronic colitis.

BACKGROUND: Oral thiopurines are effective and widely used in treatment of inflammatory bowel disease (IBD) in humans, although their use is limited due the development of adverse events. Here, we examine the efficacy and toxicity of oral treatment with 6-tioguanine (6-TG) and azathioprine (AZA) in a murine model of IBD. METHODS: We induced acute or chronic colitis in BALB/c mice by one or four cycles of 3% dextran sulphate sodium (DSS), respectively. Mice were treated by daily gavages of various dosages of 6-tioguanine, azathioprine, or by phosphate buffered saline (PBS) starting the first day of DSS or after two cycles of DSS, respectively. We monitored the efficacy and toxicity by measuring the weight change and serum alanine aminotransferase (ALT) activity and by disease severity and histology, at the end of the experiment. Moreover, we measured cytokine production after colon fragment cultivation by enzyme-linked immunoabsorbent assay and numbers of apoptotic cells in the spleen by flow cytometry. RESULTS: 6-TG is effective in the treatment of acute DSS-induced colitis in a dose-dependent manner and 40 µg of 6-TG is significantly more effective in the treatment of acute colitis than both AZA and PBS. This effect is accompanied by decrease of IL-6 and IFN-γ production in colon. We did not observe histological abnormalities in liver samples from control (PBS) or 6-TG treated mice. However, liver samples from most mice treated with AZA showed mild, yet distinct signs of hepatotoxicity. In chronic colitis, all thiopurine derivatives improved colitis, 20 µg of 6-TG per dose was superior. High doses of 6-TG led to significant weight loss at the end of the therapy, but none of the thiopurine derivatives increased levels of serum ALT. Both thiopurine derivatives reduced the proportion of apoptotic T helper cells, but a high production of both IL-6 and TGF-ß was observed only in colon of AZA-treated mice. CONCLUSIONS: Use of 6-TG in the treatment of experimental colitis in mice appears superior to AZA administration and placebo. In contrast to 6-TG, the use of AZA resulted in histological liver abnormalities.

Continuation of Anti-TNF in Patients With Ulcerative Colitis in Remission Is Not Cost-effective Compared With Treatment Withdrawal: A Markov Model.

BACKGROUND AND AIMS: Anti-tumour necrosis factor alpha [anti-TNF] treatment accounts for 31% of health care expenditures associated with ulcerative colitis [UC]. Withdrawal of anti-TNF in patients with UC in remission may decrease side effects and infections, while promoting cost containment. Approximately 36% of patients relapse within 12-24 months of anti-TNF withdrawal, but reintroduction of treatment is successful in 80% of patients. We aimed to evaluate the cost-effectiveness of continuation versus withdrawal of anti-TNF in patients with UC in remission. METHODS: We developed a Markov model comparing cost-effectiveness of anti-TNF continuation versus withdrawal, from a health care provider perspective. Transition probabilities were calculated from literature, or estimated by an expert panel of 11 gastroenterologists. Deterministic and probabilistic sensitivity analyses were performed to account for assumptions and uncertainty. The cost-effectiveness threshold was set at an incremental cost-effectiveness ratio of €80,000 per quality-adjusted life-year [QALY]. RESULTS: At 5 years, anti-TNF withdrawal was less costly [-€10,781 per patient], but also slightly less effective [-0.04 QALY per patient] than continued treatment. Continuation of anti-TNF compared with withdrawal costs €300,390/QALY, exceeding the cost-effectiveness threshold. Continued therapy would become cost-effective if the relapse rate following anti-TNF withdrawal was ≥43% higher, or if adalimumab or infliximab [biosimilar] prices fell below €87/40 mg and €66/100 mg, respectively. CONCLUSIONS: Continuation of anti-TNF in UC patients in remission is not cost-effective compared with withdrawal. A stop-and-reintroduction strategy is cost-saving but is slightly less effective than continued therapy. This strategy could be improved by identifying patients at increased risk of relapse.

Loss of response to anti-TNFα agents depends on treatment duration in patients with inflammatory bowel disease.

BACKGROUND: Inflammatory bowel disease (IBD) is often managed with anti-tumour necrosis factor-α therapy (anti-TNFα), but treatment efficacy is compromised by high annual rates of loss of response (13%-21% per patient-year). AIMS: To assess whether the incidence of loss of response decreases with longer treatment duration METHODS: This was a multicentre, retrospective cohort study of patients with ulcerative colitis (UC) or Crohn's disease (CD) who received anti-TNFα for at least 4 months between 2011 and 2019. We studied the incidence of loss of response as a function of treatment duration, employing parametric survival modelling. Predictors of loss of response were identified by Cox regression analysis. Secondary outcomes included overall anti-TNFα discontinuation and dose escalation. RESULTS: We included 844 anti-TNFα treatment episodes in 708 individuals. Loss of response occurred in 211 (25.0%) episodes, with anti-drug antibodies detected in 66 (31.3%). During the first year, the incidence of loss of response was three-fold higher than after four years of treatment (17.2% vs 4.8% per patient-year, P < 0.001). The incidence of anti-TNFα discontinuation (28.6% vs 14.0% per patient-year, P < 0.001) and dose escalations (38.0% vs 6.8% per patient-year, P < 0.001) also decreased significantly from the first year to after four years, respectively. Predictors of loss of response included UC (vs CD, adjusted hazard ratio [aHR] 1.53, 95% CI 1.10-2.15) and, among patients with CD, stricturing or penetrating disease (aHR 1.68, 95% CI 1.15-2.46) and male sex (aHR 0.55, 95% CI 0.38-0.78). Immunomodulators were protective against loss of response with anti-drug antibodies (aHR 0.42, 95% CI 0.24-0.74). CONCLUSIONS: Patients with sustained benefit to anti-TNFα after 2 years are at low risk of subsequent loss of response.

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.

Thiopurines in Inflammatory Bowel Disease: New Findings and Perspectives.

Thiopurines, available as azathioprine, mercaptopurine, and thioguanine, are immunomodulating agents primarily used to maintain corticosteroid-free remission in patients with inflammatory bowel disease. To provide a state-of-the-art overview of thiopurine treatment in inflammatory bowel disease, this clinical review critically summarises the available literature, as assessed by several experts in the field of thiopurine treatment and research in inflammatory bowel disease.