Relapse rates and predictors for relapse in a real-life cohort of IBD patients after discontinuation of anti-TNF therapy

Immunological Avalanches in Renal Immune Diseases

The complex nature of immune system behavior in both autoimmune diseases and transplant rejection can be understood through the lens of avalanche dynamics in critical-point systems. This paper introduces the concept of the "immunological avalanche" as a framework for understanding unpredictable patterns of immune activity in both contexts. Just as avalanches represent sudden releases of accumulated potential energy, immune responses exhibit periods of apparent stability followed by explosive flares triggered by seemingly minor stimuli. The model presented here draws parallels between immune system behavior and other complex systems such as earthquakes, forest fires, and neuronal activity, where localized events can propagate into large-scale disruptions. In autoimmune conditions like systemic lupus erythematosus (SLE), which affects multiple organ systems including the kidneys in approximately 50% of patients, these dynamics manifest as alternating periods of remission and flares. Similarly, in transplant recipients, the immune system exhibits metastable behavior under constant allograft stimulation. This critical-point dynamics framework is characterized by threshold-dependent activation, positive feedback loops, and dynamic non-linearity. In autoimmune diseases, triggers such as UV light exposure, infections, or stress can initiate cascading immune responses. In transplant patients, longitudinal analysis reveals how monitoring oscillatory patterns in blood parameters and biological age markers can predict rejection risk. In a preliminary study on kidney transplant, all measured variables showed temporal instability. Proteinuria exhibited precise log-log linearity in power law analysis, confirming near-critical-point system behavior. Two distinct dynamic patterns emerged: large oscillations in eGFR, proteinuria, or biological age predicted declining function, while small oscillations indicated stability. During avalanche events, biological age increased dramatically, with partial reversal leaving persistent elevation after acute episodes. Understanding these dynamics has important implications for therapeutic approaches in both contexts. Key findings suggest that monitoring parameter oscillations, rather than absolute values, better indicates system instability and potential avalanche events. Additionally, biological age calculations provide valuable prognostic information, while proteinuria measurements offer efficient sampling for system dynamics assessment. This conceptual model provides a unifying framework for understanding the pathogenesis of both autoimmune and transplant-related immune responses, potentially leading to new perspectives in disease management and rejection prediction.

Measurement of Anti-TNF Biologics in Serum Samples of Pediatric Patients: Comparison of Enzyme-Linked Immunosorbent Assay (ELISA) with a Rapid and Automated Fluorescence-Based Lateral Flow Immunoassay

Background: Therapeutic drug monitoring (TDM) of infliximab (IFX) and adalimumab (ADL) mainly relies on the use of enzyme-linked immunosorbent assays (ELISA). More recently, rapid assays have been developed and validated to reduce turnaround time (TAT). Here, we compared IFX and ADL concentrations measured with both ELISA and a new fluorescence-based lateral flow immunoassay (AFIAS). Methods: In serum samples from pediatric patients, IFX and ADL drug levels, and total anti-IFX antibodies were measured using clinically validated ELISA kits (Immundiagnostik AG). Samples were further analyzed using a new rapid assay (AFIAS, Boditech Med Inc.) to measure drug levels and total anti-IFX antibodies. Results: Spearman's correlation coefficients (rho) were 0.98 [95% confidence interval (CI) 0.97 to 0.99] for IFX (p < 0.001) and 0.83 (95% CI 0.72 to 0.90) for ADL (p < 0.001). Calculated % bias was -14.09 (95% Limits of agreement, LoA, -52.83 to 24.66) for IFX and 15.79 (LoA -37.14 to 68.73) for ADL. For the evaluation of total anti-IFX antibodies, we did not collect sufficient data to establish a statistically significant correlation between AFIAS and ELISA. The inter-rater agreement showed a "substantial" and a "moderate" agreement for IFX and ADL, respectively. Conclusions: Our results show that the AFIAS assay has an accuracy and analytical performance comparable to that of the ELISA method used for TDM of IFX and ADL. Therefore, the introduction of this device into routine clinical practice could provide results more quickly and with similar accuracy as ELISA, allowing clinicians to rapidly formulate clinical decisions.

Biological agents as attractive targets for inflammatory bowel disease therapeutics

Inflammatory bowel disease (IBD) refers to a group of chronic, recurrent intestinal inflammatory conditions with a complex cause and unclear underlying mechanisms. It includes two main types: Ulcerative colitis (UC) and Crohn's disease (CD). The conventional treatment of IBD mainly includes 5-aminosalicylates, glucocorticoids, and immunosuppressive drugs, which have their limitations. Recent advancements in IBD research have expanded treatment options, with biological agents playing a key role. Anti-tumor necrosis factor alpha has emerged as the first-line therapy for moderate to severe IBD. Anti-integrin antibodies have also become important for the treatment, and vedolizumab is often used in cases of anti-tumor necrosis factor-alpha failure and intolerance to other treatments. Other biological agents are being tested in clinical trials at different stages. This article reviews the efficacy and safety of the primary biological therapies for IBD and provides a comprehensive analysis of the current clinical challenges associated with the disease.

The Potential of Molecular Remission: Tissue Neutrophil Elastase Is Better Than Histological Activity for Predicting Long-Term Relapse in Patients With Ulcerative Colitis in Endoscopic Remission

BACKGROUND

Growing interest exists in deep remission, beyond clinical and endoscopic remission, to enhance long-term prognosis in patients with ulcerative colitis (UC). Our study aimed to evaluate the risk of relapse according to tissue expression levels of calprotectin and neutrophil elastase (NE) in patients with quiescent UC.

METHODS

Rectal biopsies were performed on 218 patients with UC in clinical and endoscopic remission. Histological activity was prospectively scored using the Robarts Histological Index. Tissue calprotectin and NE levels were evaluated using immunohistochemistry. Optimal tissue calprotectin and NE cutoffs for relapse were determined using log-rank analysis. Cox proportional hazard analyses evaluated relapse risk factors.

RESULTS

Tissue calprotectin and NE levels were significantly higher in patients with histological activity than in those in histological remission (P < .001). The optimal cutoffs of tissue calprotectin and NE for relapse were 10.61 and 22.08 per mm2, respectively. The 3-year clinical relapse risk was significantly lower in the low-tissue NE group than in the high-tissue NE group (P = .009); however, it did not differ between the low- and high-tissue calprotectin group (P = .094). In multivariate analyses, a low level of tissue NE expression was independently associated with a lower risk of 3-year clinical relapse (adjusted hazard ratio = 0.453, 95% confidence interval = 0.225-0.911, P = .026), unlike histological index and tissue calprotectin.

CONCLUSIONS

In patients with UC who have achieved clinical and endoscopic remission, tissue expression of NE is a better predictor of long-term relapse than histological activity.

Psoriasis induced by antiTNF therapy in inflammatory bowel disease: Therapeutic management and evolution of both diseases in a nationwide cohort study

BACKGROUND

some patients with inflammatory bowel disease (IBD) treated with antiTNF develop drug-induced psoriasis (antiTNF-IP). Several therapeutic strategies are possible.

AIMS

to assess the management of antiTNF-IP in IBD, and its impact in both diseases.

METHODS

patients with antiTNF-IP from ENEIDA registry were included. Therapeutic strategy was classified as continuing the same antiTNF, stopping antiTNF, switch to another antiTNF or swap to a non-antiTNF biologic. IP severity and IBD activity were assessed at baseline and 16, 32 and 54 weeks.

RESULTS

234 patients were included. At baseline, antiTNF-IP was moderate-severe in 60 % of them, and IBD was in remission in 80 %. Therapeutic strategy was associated to antiTNF-IP severity (p < 0.001). AntiTNF-IP improved at week 54 with all strategies, but continuing with the same antiTNF showed the worst results (p = 0.042). Among patients with IBD in remission, relapse was higher in those who stopped antiTNF (p = 0.025). In multivariate analysis, stopping antiTNF, trunk and palms and soles location were associated with antiTNF-IP remission; female sex and previous surgery in Crohn´s disease with IBD relapse.

CONCLUSION

skin lesions severity and IBD activity seem to determine antiTNF-IP management. Continuing antiTNF in mild antiTNF-IP, and swap to ustekinumab or switch to another antiTNF in moderate-severe cases, are suitable strategies.

Risk factors affecting relapse after discontinuation of biologics in children with Crohn's disease who maintained deep remission

Objectives

Biologics are important therapeutic agents for pediatric Crohn's disease. Discontinuation of biologics is known to increase the relapse rate up to 71.4% in these patients; however, their long-term use increases the risk of opportunistic infections and causes economic burden and psychological fatigue. Therefore, taking a drug holiday is meaningful, even if the biologics cannot be completely discontinued. This study aimed to analyze the risk factors affecting relapse after discontinuation of biologics in children with Crohn's disease.

Methods

We retrospectively reviewed the data of 435 children with Crohn's disease who visited a single health center between March 2013 and March 2021. Subsequently, we analyzed data from the patients who discontinued biologics after deep remission.

Results

Among the enrolled patients, 388 were followed up for ≥2 years, and of these, 357 were administered biologics. A total of 103 patients discontinued biologics after deep remission, subsequently 31 maintained remission and 72 relapsed. The shorter the duration of biologic treatment (odds ratio of 0.444, P = 0.029), the higher the ESR (odds ratio of 1.294, P = 0.009) and fecal calprotectin (odds ratio of 1.010, P = 0.032), and the less histological remission at the time of discontinuation of biologics (odds ratio of 0.119, P = 0.026), the greater the risk of relapse after discontinuation of biologics.

Conclusions

We identified factors associated with relapse after discontinuation of biologics. The results suggest that biologics can be discontinued in the absence of these factors after deep remission. However, because the relapse rate may increase after the discontinuation of biologics, close monitoring is important, and if necessary, re-administration of biologics should be actively considered.

De-escalating therapy in inflammatory bowel disease: Results from an observational study in clinical practice

BACKGROUND AND OBJECTIVES

Combination therapy with an immunomodulator (IMM) and an anti-TNF is commonly recommended in Crohn's disease (CD) and ulcerative colitis (UC) patients. However, little is known about relapse rates after therapeutic de-escalation. This study aimed to evaluate the risk of relapse in a cohort of UC and CD patients with long-standing clinical remission after discontinuation of IMM or anti-TNF and to identify predictive factors for relapse.

METHODS

This retrospective study included patients with UC or CD on combination therapy and clinical remission for at least 6 months. IMM or anti-TNF was stopped upon physician decision. Primary objective was to evaluate the relapse rates after discontinuation of IMM or anti-TNF and to analyze predictors of relapse.

RESULTS

The study included 88 patients, 48 patients (54.5%) discontinued IMM and 40 (45.5%) anti-TNF. During follow-up, relapse rates were 16.7% and 52.5% in the IMM discontinuation group and anti-TNF discontinuation group, respectively (p<0.001). Multivariate analysis showed that anti-TNF discontinuation (HR=3.01; 95% CI=1.22-7.43) and ileal CD location (HR=2.36; 95% CI=1.02-5.47) were predictive factors for relapse while inflammatory CD phenotype was a protective factor (HR=0.32; 95% CI=0.11-0.90). Reintroduction of anti-TNF upon relapse was effective and safe.

CONCLUSION

Anti-TNF discontinuation led to significantly higher relapse rates compared to IMM discontinuation in UC and CD patients on combination therapy. Anti-TNF discontinuation and ileal CD location were identified as predictive factors for relapse while inflammatory CD phenotype was a protective factor. Retreatment after anti-TNF discontinuation was effective and safe.

Estimation of patients affected by inflammatory bowel disease potentially eligible for biological treatment in a real-world setting

BACKGROUND/AIMS

This analysis estimated the number of inflammatory bowel disease (IBD) patients presenting criteria of eligibility for biological therapies in an Italian real-world setting.

METHODS

An observational analysis was performed on administrative databases of a sample of Local Health Units, covering 11.3% of the national population. Adult IBD patients (CD or UC) from 2010 to the end of data availability were included. Eligibility criteria for biologics were the following: Criterion A, steroid-refractory active disease; Criterion B, steroid-dependent patients; Criterion C, intolerance or contraindication to conventional therapies; Criterion D, severe relapsing disease; Criterion E (CD only), highly active CD disease and poor prognosis.

RESULTS

Of 26,781 IBD patient identified, 18,264 (68.2%) were treated: 3,125 (11.7%) with biologics and 15,139 (56.5%) non-biotreated. Among non-biotreated, 7,651 (28.6%) met at least one eligibility criterion for biologics, with criterion B (steroid-dependence) and criterion D (relapse) as the most represented (58-27% and 56-76%, respectively). Data reportioned to the Italian population estimated 67,635 patients as potentially eligible for biologics.

CONCLUSIONS

This real-world analysis showed a trend towards undertreatment with biologics in IBD patients with 28.6% being potentially eligible, suggesting that an unmet medical need still exists among the Italian general clinical practice for IBD management.

Long-term clinical outcomes after the discontinuation of anti-TNF agents in patients with inflammatory bowel disease: a meta-analysis

BACKGROUND

there are concerns regarding the risk of relapse after discontinuation of anti-tumor necrosis factor (anti-TNF) therapy in patients with inflammatory bowel disease (IBD). A systematic review and meta-analysis were performed to evaluate the risk of relapse after discontinuation of anti-TNF agent in patients, and the response to retreatment with the same anti-TNF agent.

METHODS

electronic databases were searched to identify relevant studies. Primary outcomes were the pooled percentage of relapses after the withdrawal of anti-TNF agents. Secondary outcomes were the pooled percentage of the response to retreatment with the same anti-TNF agent after relapse.

RESULTS

thirty-seven studies were included in this meta-analysis. The overall risk of relapse after discontinuation of anti-TNF agent was 43 % for ulcerative colitis (UC) and 43 % for Crohn's disease (CD). In UC, the relapse rate was 37 % at 1-2 year, and 58 % at 3-5 years. In CD, the relapse rate was 38 % at 1-2 year, 53 % at 3-5 years, and 49 % at more than five years. When clinical remission was the only criterion for stopping anti-TNF agent, the relapse rate was 42 % in UC and 45 % in CD, which decreased to 40 % in UC and 36 % in CD when clinical remission and endoscopic healing were required. Retreatment with the same anti-TNF agent induced remission again in 78 % of UC patients and 76 % of CD patients.

CONCLUSION

our meta-analysis showed that a high proportion of IBD patients will relapse after discontinuation of anti-TNF agent. The response to retreatment with the same anti-TNF agent is generally favorable in patients who relapse.

Relapse rates after withdrawal versus maintaining biologic therapy in IBD patients with prolonged remission

Biologic treatment withdrawal in inflammatory bowel disease patients with prolonged remission may lead to benefits but also increases the risk of getting a relapse. The risk of relapse after biologic withdrawal according to the Dutch STOP-criteria is still unknown. The aim of this study was to compare the cumulative incidence of relapse in inflammatory bowel disease patients that discontinued biologic therapy after applying the STOP-criteria with patients who maintained biologic therapy. We performed a mono-centre, observational, retrospective study by evaluating relapse risk of patients treated with biologic agents who discontinued this treatment according to the STOP-criteria (STOP-group) compared to patients who were in remission for more than 3 years before withdrawal (LATERSTOP-group) and patients who continued their biologic (MAINTAIN-group). The cumulative risk was calculated at 12 and 36 months using the log-rank test to compare Kaplan-Meier curves. Eighty-three of 398 patients that used biologics between 1 January 2010 and 1 January 2020 were included. The cumulative relapse incidences in the STOP-group and the LATERSTOP-group were, respectively, 29% and 42% at 12 months and 47% versus 58% at 36 months. Patients in the MAINTAIN-group showed a lower (p = 0.03) cumulative relapse incidence of 10% at 12 months and 18% at 36 months. Patients who discontinued their biologic therapy according to the STOP-criteria had significantly more relapses at 12 and 36 months than patients who maintained biologic treatment.

Impact of the COVID-19 Pandemic on the Lifestyle and Psychosocial Behavior of Patients with Inflammatory Bowel Diseases: A Narrative Review

The coronavirus disease (COVID-19) pandemic has had a considerable impact on the global healthcare system and potentially the clinical course of patients with inflammatory bowel disease (IBD). Although IBD is a chronic disease, its therapy (except steroid therapy) does not increase the risk of contracting or aggravating COVID-19. However, the clinical course of patients is significantly influenced by environmental factors. Social restrictions due to the pandemic or the fear of contracting the virus have influenced lifestyle and psychosocial behaviors that may worsen the clinical course of patients with IBD. This narrative literature review summarizes the current evidence on the impact of the COVID-19 pandemic on the lifestyle and psychosocial behaviors of patients with IBD. The COVID-19 pandemic negatively affected the lifestyle and psychosocial behaviors of patients with IBD. Furthermore, patients with IBD failed to maintain medication adherence, thus affecting the clinical course of their condition.

Constructing a prediction model of inflammatory bowel disease recurrence based on factors affecting the quality of life

Aim

This study aimed to determine the factors affecting the quality of life of patients with inflammatory bowel disease (IBD) and to construct a disease recurrence prediction model based on these influencing factors.

Methods

A prospective, single-center study in China was conducted between October 2020 and March 2021. The quality of life of patients was assessed using the Inflammatory Bowel Disease Questionnaire (IBDQ). Multiple stepwise regression analysis was used to analyze the factors influencing the quality of life of patients with IBD. The chi-square test and the point-biserial correlation analysis were performed to identify factors associated with clinical recurrence. A binary logistic regression model was constructed to predict the recurrence. The receiver operating characteristic curve was used to evaluate the prediction model. Patients with IBD from April 2021 to June 2021 were randomly included for model verification to evaluate the disease recurrence prediction model.

Results

The average IBDQ score of patients with IBD was 172.2 ± 35.0 (decreased by 23.2%). The scores of all dimensions of the IBDQ were decreased, especially emotional function and systemic symptoms. Disease activity, age, extraintestinal manifestations (EIMs), and annual household income were important factors influencing the IBDQ scores of patients with ulcerative colitis, and these accounted for ~57.0% of the factors affecting the quality of life. Disease activity, EIMs, and occupational stress were important factors influencing the IBDQ scores of patients with Crohn's disease, and they accounted for approximately 75.1% of the factors affecting the quality of life. Annual household income, occupational stress, and IBDQ scores were independent risk factors for recurrence. The area under the curve of the recurrence prediction model was 81.1%. The sensitivity and specificity were 81.7 and 71.7%, respectively. The Youden index of the model was 0.534. The established recurrence prediction model has good discriminant validity in the validation cohort.

Conclusion

The quality of life of patients with IBD was generally poor. The use of factors affecting the quality of life to predict disease recurrence has high predictive value and can support the management of IBD by selecting patients at a higher risk for relapse.

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.

Validation and update of a prediction model for risk of relapse after cessation of anti-TNF treatment in Crohn's disease

BACKGROUND

Anti-tumor necrosis factor (TNF) therapy is effective for the treatment of Crohn's disease. Cessation may be considered in patients with a low risk of relapse. We aimed to externally validate and update our previously developed prediction model to estimate the risk of relapse after cessation of anti-TNF therapy.

METHODS

We performed a retrospective cohort study in 17 Dutch hospitals. Crohn's disease patients in clinical, biochemical or endoscopic remission were included after anti-TNF cessation. Primary outcome was a relapse necessitating treatment. Discrimination and calibration of the previously developed model were assessed. After external validation, the model was updated. The performance of the updated prediction model was assessed in internal-external validation and by using decision curve analysis.

RESULTS

486 patients were included with a median follow-up of 1.7 years. Relapse rates were 35 and 54% after 1 and 2 years. At external validation, the discriminative ability of the prediction model was equal to that found at the development of the model [c-statistic 0.58 (95% confidence interval (CI) 0.54-0.62)], though the model was not well-calibrated on our cohort [calibration slope: 0.52 (0.28-0.76)]. After an update, a c-statistic of 0.60 (0.58-0.63) and calibration slope of 0.89 (0.69-1.09) were reported in internal-external validation.

CONCLUSION

Our previously developed and updated prediction model for the risk of relapse after cessation of anti-TNF in Crohn's disease shows reasonable performance. The use of the model may support clinical decision-making to optimize patient selection in whom anti-TNF can be withdrawn. Clinical validation is ongoing in a prospective randomized trial.

How to Manage Inflammatory Bowel Disease Patients When They Withdraw Anti-Tumour Necrosis Factor [Anti-TNF] Due to Severe Anti-TNF-Induced Skin Lesions? A Multicentre Cohort Study

BACKGROUND AND AIMS

Optimal management of patients with inflammatory bowel disease [IBD] after anti-tumour necrosis factor [TNF] discontinuation due to severe induced skin lesions is unclear. Our study aimed to describe dermatological and IBD evolution after anti-TNF discontinuation for this side effect.

METHODS

We conducted a multicentre retrospective study including consecutive IBD patients who discontinued anti-TNF due to severe induced skin lesions. Our objectives were to determine factors associated with dermatological remission [complete disappearance of skin lesions] and with IBD relapse in patients with inactive disease at inclusion, notably the impact of an early switch to another biological agent within 3 months of anti-TNF discontinuation.

RESULTS

Among the 181 patients [134 women, 160 Crohn's disease] included in the 13 participating centres, dermatological remission occurred in 110 [62%] patients with a median [interquartile range, IQR] interval of 8.0 [6.8-11.0] months. Scalp location was independently associated with less remission of skin lesions (hazard ratio [HR] = 0.64 [95% CI 0.43-0.94], p = 0.02) while early switch was independently associated with a higher probability of remission of skin lesions (HR = 1.64 [95% CI 1.1-2.5], p = 0.02). Among the 148 patients with inactive IBD at inclusion, disease relapse occurred in 75 [51%] patients with a median [IQR] interval of 26.0 [23.0-39.1] months. Survival rates without IBD relapse at 1 year were 85.8% [95% CI 77.5-94.9] in the early switch group and 59.3% [95% CI 48.9-71.9] in the other group [p < 0.01].

CONCLUSIONS

Early switch to a new biological is associated with a higher probability of healing of anti-TNF-induced skin lesions and significantly reduces the risk of IBD relapse.

Prediction of Relapse After Anti-Tumor Necrosis Factor Cessation in Crohn's Disease: Individual Participant Data Meta-analysis of 1317 Patients From 14 Studies

BACKGROUND & AIMS

Tools for stratification of relapse risk of Crohn's disease (CD) after anti-tumor necrosis factor (TNF) therapy cessation are needed. We aimed to validate a previously developed prediction model from the diSconTinuation in CrOhn's disease patients in stable Remission on combined therapy with Immunosuppressants (STORI) trial, and to develop an updated model.

METHODS

Cohort studies were selected that reported on anti-TNF cessation in 30 or more CD patients in remission. Individual participant data were requested for luminal CD patients and anti-TNF treatment duration of 6 months or longer. The discriminative ability (concordance-statistic [C-statistic]) and calibration (agreement between observed and predicted risks) were explored for the STORI model. Next, an updated prognostic model was constructed, with performance assessment by cross-validation.

RESULTS

This individual participant data meta-analysis included 1317 patients from 14 studies in 11 countries. Relapses after anti-TNF cessation occurred in 632 of 1317 patients after a median of 13 months. The pooled 1-year relapse rate was 38%. The STORI prediction model showed poor discriminative ability (C-statistic, 0.51). The updated model reached a moderate discriminative ability (C-statistic, 0.59), and included clinical symptoms at cessation (hazard ratio [HR], 2.2; 95% CI, 1.2-4), younger age at diagnosis (HR, 1.5 for A1 (age at diagnosis ≤16 years) vs A2 (age at diagnosis 17 - 40 years); 95% CI, 1.11-1.89), no concomitant immunosuppressants (HR, 1.4; 95% CI, 1.18-172), smoking (HR, 1.4; 95% CI, 1.15-1.67), second line anti-TNF (HR, 1.3; 95% CI, 1.01-1.69), upper gastrointestinal tract involvement (HR, 1.3 for L4 vs non-L4; 95% CI, 0.96-1.79), adalimumab (HR, 1.22 vs infliximab; 95% CI, 0.99-1.50), age at cessation (HR, 1.2 per 10 years younger; 95% CI, 1-1.33), C-reactive protein (HR, 1.04 per doubling; 95% CI, 1.00-1.08), and longer disease duration (HR, 1.07 per 5 years; 95% CI, 0.98-1.17). In subanalysis, the discriminative ability of the model improved by adding fecal calprotectin (C-statistic, 0.63).

CONCLUSIONS

This updated prediction model showed a reasonable discriminative ability, exceeding the performance of a previously published model. It might be useful to guide clinical decisions on anti-TNF therapy cessation in CD patients after further validation.

Tumour necrosis factor inhibitors in inflammatory bowel disease: the story continues

In the 1990s, tumour necrosis factor-α inhibitor therapy ushered in the biologic therapy era for inflammatory bowel disease, leading to marked improvements in treatment options and patient outcomes. There are currently four tumour necrosis factor-α inhibitors approved as treatments for ulcerative colitis and/or Crohn's disease: infliximab, adalimumab, golimumab and certolizumab pegol. Despite the clear benefits of tumour necrosis factor-α inhibitors, a subset of patients with inflammatory bowel disease either do not respond, experience a loss of response after initial clinical improvement or report intolerance to anti-tumour necrosis factor-α therapy. Optimizing outcomes of these agents may be achieved through earlier intervention, the use of therapeutic drug monitoring and thoughtful switching within class. To complement these approaches, evolving predictive biomarkers may help inform and optimize clinical decision making by identifying patients who might potentially benefit from an alternative treatment strategy. This review will focus on the current use of tumour necrosis factor-α inhibitors in inflammatory bowel disease and the application of personalized medicine to improve future outcomes for all patients.

Combination Immunotherapy Use and Withdrawal in Pediatric Inflammatory Bowel Disease-A Review of the Evidence

Evidence-based guidelines have been developed outlining the concomitant use of anti-tumor necrosis factor alpha (anti-TNF) agents and immunomodulators including azathioprine (AZA) and methotrexate (MTX) in both adult and pediatric populations. However, there exists a paucity of data guiding evidence-based strategies for their withdrawal in pediatric patients in sustained remission. This narrative review focuses on the available pediatric evidence on this question in the context of what is known from the larger body of evidence available from adult studies. The objective is to provide clarity and practical guidance around who, what, when, and how to step down pediatric patients with inflammatory bowel disease (IBD) from combination immunotherapy. Outcomes following withdrawal of either of the two most commonly used anti-TNF therapies [infliximab (IFX) or adalimumab (ADA)], or immunomodulator therapies, from a combination regimen are examined. Essentially, a judicious approach must be taken to identify a significant minority of patients who would benefit from treatment rationalization. We conclude that step-down to anti-TNF (rather than immunomodulator) monotherapy after at least 6 months of sustained clinical remission is a viable option for a select group of pediatric patients. This group includes those with good indicators of mucosal healing, low or undetectable anti-TNF trough levels, lack of predictors for severe disease, and no prior escalation of anti-TNF therapy. Transmural healing and specific human leukocyte antigen (HLA) typing are some of the emerging targets and tools that may help facilitate improved outcomes in this process. We also propose a simplified evidence-based schema that may assist in this decision-making process. Further pediatric clinical studies are required to develop the evidence base for decision-making in this area.

Limited long-term treatment persistence of first anti-TNF therapy in 538 patients with inflammatory bowel diseases: a 20-year real-world study

BACKGROUND

Anti-TNF antibodies were the first biologic treatment option for patients with inflammatory bowel diseases.

AIMS

To assess length of treatment persistence of first anti-TNF therapy and influencing factors used in the standard care of patients with inflammatory bowel diseases.

METHODS

Single-centre, retrospective study from a register including patients who received anti-TNF therapy in the last 20 years at the study centre. Kaplan-Meier analysis with log-rank test was used to describe treatment persistence. With multivariable Cox regression analysis, risk factors for treatment failure were investigated.

RESULTS

Five hundred thirty-eight patients (CD, Crohn's disease: 367, UC, ulcerative colitis: 147, inflammatory bowel disease unclassified: 24) with a median follow-up of 8.1 years were included. Median (95% confidence interval) treatment persistence in the total cohort was 2.3 years (28 [22, 38] months), and nearly half of patients withdrew from treatment within 2 years. Male patients were treated longer than females (male: 37 [25, 48] months, female: 23 [14, 33] months, P = 0.002). Treatment persistence was longer in CD compared to UC (CD: 39 [30, 50] months, UC: 13 [9, 19] months, P < 0.001), and patients with CD remained longer on adalimumab than on infliximab treatment (adalimumab: 67 [55, 95] months, infliximab: 19 [14, 31] months, P < 0.001). Treatment failure (52%) and side effects (25%) were the most common reasons for withdrawal from therapy; 14% withdrew due to remission. Female sex was identified as independent predictor for treatment failure in UC (hazard ratio [CI]: 1.73 [1.02-2.92], P = 0.04).

CONCLUSION

Long-term treatment persistence of first anti-TNF therapy was limited in patients with inflammatory bowel diseases, primarily due to treatment failure and side effects.

Clinical outcome after anti-tumour necrosis factor therapy discontinuation in 1000 patients with inflammatory bowel disease: the EVODIS long-term study

BACKGROUND

The long-term outcome of patients after antitumour necrosis factor alpha (anti-TNF) discontinuation is not well known.

AIMS

To assess the risk of relapse in the long-term after anti-TNF discontinuation.

METHODS

This was an extension of the evolution after anti-TNF discontinuation in patients with inflammatory bowel disease (EVODIS) study (Crohn's disease or ulcerative colitis patients treated with anti-TNFs in whom these drugs were withdrawn after achieving clinical remission) based in the same cohort of patients whose outcome was updated. Clinical remission was defined as a Harvey-Bradshaw index ≤4 points in Crohn's disease, a partial Mayo score ≤2 in ulcerative colitis and the absence of fistula drainage despite gentle finger compression in perianal disease.

RESULTS

This was an observational, retrospective, multicenter study. A total of 1055 patients were included. The median follow-up time was 34 months. The incidence rate of relapse was 12% per patient-year (95% confidence interval [CI] = 11-14). The cumulative incidence of relapse was 50% (95% CI = 47-53): 19% at one year, 31% at 2 years, 38% at 3 years, 44% at 4 years and 48% at 5 years of follow-up. Of the 60% patients retreated with the same anti-TNF after relapse, 73% regained remission. Of the 75 patients who did not respond, 48% achieved remission with other therapies. Of the 190 patients who started other therapies after relapse, 62% achieved remission with the new treatment.

CONCLUSIONS

A significant proportion of patients who discontinued the anti-TNF remained in remission. In case of relapse, retreatment with the same anti-TNF was usually effective. Approximately half of the patients who did not respond after retreatment achieved remission with other therapies.

Personalized Medicine of Monoclonal Antibodies in Inflammatory Bowel Disease: Pharmacogenetics, Therapeutic Drug Monitoring, and Beyond

The pharmacotherapy of inflammatory bowel diseases (Crohn’s disease and ulcerative colitis) has experienced significant progress with the advent of monoclonal antibodies (mABs). As therapeutic proteins, mABs display peculiar pharmacokinetic characteristics that differentiate them from chemical drugs, such as aminosalicylates, antimetabolites (i.e., azathioprine, 6-mercaptopurine, and methotrexate), and immunosuppressants (corticosteroids and cyclosporine). However, clinical trials have demonstrated that biologic agents may suffer from a pharmacokinetic variability that could influence the desired clinical outcome, beyond primary resistance phenomena. Therefore, therapeutic drug monitoring (TDM) protocols have been elaborated and applied to adaptation drug doses according to the desired plasma concentrations of mABs. This activity is aimed at maximizing the beneficial effects of mABs while sparing patients from toxicities. However, some aspects of TDM are still under discussion, including time-changing therapeutic ranges, proactive and reactive approaches, the performance and availability of instrumental platforms, the widely varying individual characteristics of patients, the severity of the disease, and the coadministration of immunomodulatory drugs. Facing these issues, personalized medicine in IBD may benefit from a combined approach, made by TDM protocols and pharmacogenetic analyses in a timeline that necessarily considers the frailty of patients, the chronic administration of drugs, and the possible worsening of the disease. Therefore, the present review presents and discusses the activities of TDM protocols using mABs in light of the most recent results, with special attention on the integration of other actions aimed at exploiting the most effective and safe therapeutic effects of drugs prescribed in IBD patients.

Imaging of the Intestinal Microcirculation during Acute and Chronic Inflammation

Because of its unique microvascular anatomy, the intestine is particularly vulnerable to microcirculatory disturbances. During inflammation, pathological changes in blood flow, vessel integrity and capillary density result in impaired tissue oxygenation. In severe cases, these changes can progress to multiorgan failure and possibly death. Microcirculation may be evaluated in superficial tissues in patients using video microscopy devices, but these techniques do not allow the assessment of intestinal microcirculation. The gold standard for the experimental evaluation of intestinal microcirculation is intravital microscopy, a technique that allows for the in vivo examination of many pathophysiological processes including leukocyte-endothelial interactions and capillary blood flow. This review provides an overview of changes in the intestinal microcirculation in various acute and chronic inflammatory conditions. Acute conditions discussed include local infections, severe acute pancreatitis, necrotizing enterocolitis and sepsis. Inflammatory bowel disease and irritable bowel syndrome are included as examples of chronic conditions of the intestine.

COVID-19 quarantine measures are associated with negative social impacts and compromised follow-up care in patients with inflammatory bowel disease in Brazil

BACKGROUND

COVID-19 has affected the entire world. We aimed to determine the impact of COVID-19 containment measures on the daily life and follow up of patients with inflammatory bowel disease (IBD).

METHODS

During May 2020, we evaluated 179 (79.6%) patients with Crohn's disease (CD) and 46 (20.4%) with ulcerative colitis (UC) by telephone, using a structured questionnaire to gather information on social impact and IBD follow up.

RESULTS

Some kind of social distancing measure was reported by 95.6% of our patients, self-quarantine (64.9%) being the most frequent. Depressive mood was the most prevalent social impact (80.2%), followed by anxiety/fear of death (58.2%), insomnia (51.4%), daily activity impairment (48%), sexual dysfunction (46.2%), and productivity impairment (44%). The results were similar when we compared patients with active disease to those in remission and patients with UC to those with CD. Analysis of IBD follow up showed that 83.1% of all patients missed an IBD medical appointment, 45.5% of the patients missed laboratory tests, 41.3% missed the national flu vaccination program, 31.3% missed any radiologic exam, 17.3% missed colonoscopy, and 16.9% failed to obtain biologic therapy prescriptions. Biologics were discontinued by 28.4% of the patients. UC patients had higher rates of missed vaccination than CD patients (56.5% vs. 37.4%, P=0.02) and more failures to obtain a biologic prescription (28.3% vs. 14.0%, P=0.02).

CONCLUSIONS

Our study reveals alarming social impacts and declining follow-up care for IBD patients during the COVID-19 outbreak. These findings may have implications for disease control in the near future.

Long-term efficacy of early infliximab-induced remission for refractory uveoretinitis associated with Behçet's disease

BACKGROUND

To evaluate long-term efficacy of infliximab (IFX) in refractory uveoretinitis associated with Behçet's disease (BD) depending on uveoretinitis duration.

METHODS

Records of 16 patients with BD (32 eyes) followed for >5 years after starting IFX, were retrospectively reviewed. Long-term efficacy was compared between patients with short duration (≤18 months, n=7) versus long duration (>18 months, n=9) of their uveoretinitis prior to starting IFX.

RESULTS

The median follow-up after starting IFX was 132 months (76-146 months). Mean frequency of attacks and the 1-year Behçet's Disease Ocular Attack Score 24 decreased significantly over 10 years. Overall, the percentage of eyes with a best-corrected visual acuity (BCVA) ≥1.0 increased from 47% at baseline to 59% at 5 years; the percentage of eyes with a BCVA ≤0.1 was 19% at both baseline and 5 years. The frequency of ocular attacks decreased similarly in both short duration and long duration groups; however, the percentage of eyes with a BCVA ≥1.0 at 5 years was 100% in the short duration group versus 28% in the long duration group. IFX was discontinued in four patients with an excellent response to IFX therapy; all were young male patients in the short duration group with good BCVA bilaterally, and none had inflammatory recurrences over a median follow-up of 56 months off IFX.

CONCLUSION

Initiation of IFX therapy in patients with BD within 18 months of their uveoretinitis onset was more effective in maintaining good BCVA than after 18 months.

Incidence and Impacts of Inflammatory Bowel Diseases among Kidney Transplant Recipients: A Meta-Analysis

Background: The incidence of inflammatory bowel diseases (IBD) and its significance in kidney transplant recipients is not well established. We conducted this systematic review and meta-analysis to assess the incidence of and complications from IBD in adult kidney transplant recipients. Methods: Eligible articles were searched through Ovid MEDLINE, EMBASE, and the Cochrane Library from inception through April 2020. The inclusion criteria were adult kidney transplant patients with reported IBD. Effect estimates from the individual studies were extracted and combined using the fixed-effects model when I2 ≤ 50% and random-effects model when I2 > 50%. Results: of 641 citations, a total of seven studies (n = 212) were included in the systematic review. The mean age was 46.2 +/− 6.9 years and up to 51.1% were male. The mean duration of follow-up was 57.8 +/− 16.8 months. The pooled incidence of recurrent IBD was 27.6% (95% CI, 17.7–40.5%; I2 0%) while the pooled incidence of de novo IBD was 18.8% (95% CI, 10.7–31.0%; I2 61.3%). The pooled incidence of post-transplant IBD was similar across subgroup analyses. Meta-regression analyses showed no association between the incidence of IBD and age, male sex, and follow-up duration. For post-transplant complications, the pooled incidence of post-transplant infection was 4.7% (95% CI, 0.5–33.3%; I2 73.7%). The pooled incidence of graft rejection and re-transplantation in IBD patients was 31.4% (95% CI, 14.1–56.1%; I2 76.9%) and 30.4% (95% CI, 22.6–39.5%; I2 0%). Conclusion: Recurrent and de novo IBD is common among kidney transplant recipients and may result in adverse outcomes.

Therapeutic drug monitoring in patients on biologics: lessons from gastroenterology

PURPOSE OF REVIEW

To give an overview on the role of therapeutic drug monitoring (TDM) of biologics in patients with inflammatory bowel disease (IBD).

RECENT FINDINGS

Numerous prospective exposure-response relationship studies and post-hoc analyses of randomized controlled trials (RCTs) show a positive correlation between biologic drug concentrations and favorable clinical outcomes in IBD. These studies also demonstrate that higher drug concentrations appear to be needed to achieve more stringent objective therapeutic outcomes. Reactive TDM rationalizes the management of primary nonresponse and secondary loss of response to antitumor necrosis factor (anti-TNF) therapy and is more cost-effective when compared with empiric dose optimization. Furthermore, recent data suggest that proactive TDM, with the goal of targeting a threshold drug concentration, is associated with better therapeutic outcomes when compared with empiric dose escalation and/or reactive TDM of infliximab or adalimumab. Finally, proactive TDM can also efficiently guide infliximab de-escalation or discontinuation in patients with IBD in remission.

SUMMARY

Reactive TDM is currently considered as standard of care, whereas proactive TDM is emerging as a new therapeutic strategy for better optimizing anti-TNF therapy in IBD. However, more data from prospective studies are needed before a wide implementation of TDM-based algorithms in real life clinical practice for newer biologics.

Optimized timing of using infliximab in perianal fistulizing Crohn's disease

Infliximab (IFX), as a drug of first-line therapy, can alter the natural progression of Crohn's disease (CD), promote mucosal healing and reduce complications, hospitalizations, and the incidence of surgery. Perianal fistulas are responsible for the refractoriness of CD and represent a more aggressive disease. IFX has been demonstrated as the most effective drug for the treatment of perianal fistulizing CD. Unfortunately, a significant proportion of patients only partially respond to IFX, and optimization of the therapeutic strategy may increase clinical remission. There is a significant association between serum drug concentrations and the rates of fistula healing. Higher IFX levels during induction are associated with a complete fistula response in these patients. Given the apparent relapse of perianal fistulizing CD, maintenance therapy with IFX over a longer period seems to be more beneficial. It appears that patients without deep remission are at an increased risk of relapse after stopping anti-tumor necrosis factor agents. Thus, only patients in prolonged clinical remission should be considered for withdrawal of IFX treatment when biomarker and endoscopic remission is demonstrated, especially when the hyperintense signals of fistulas on T2-weighed images have disappeared on magnetic resonance imaging. Fundamentally, the optimal timing of IFX use is highly individualized and should be determined by a multidisciplinary team.

Assessment of the State of Cell Membranes against the Background of Prolonged Use of Anticytokine Therapy in Patients with Ulcerative Colitis

Biological therapy in the treatment of immune-mediated conditions has changed their course, the quality of life of patients and the prognosis of diseases. The accumulated by mankind 20 years of experience with the use of genetically engineered drugs has led to a number of questions regarding, among other issues, safety in the long-term administration of biological therapy. Patients suffering from ulcerative colitis revealed changes in cell membranes, reflecting their structural and energy characteristics. Long-term administration of Infliximab leads to the stabilization of energy processes in the erythrocyte membrane and improves homeostatic function of the kidneys.The aim of the study was to evaluate the effect of long-term use of TNF-α blockers (Infliximab) on the structural and functional characteristics of cell membranes and the functional state of the kidneys in patients with moderate to severe ulcerative colitis.Materials and methods. We examined 103 patients with moderate to severe ulcerative colitis during the period of acute attack and remission, of which 28 patients received basic therapy using the drug Infliximab (IFX) for 10 years, 75 patients received standard basic treatment. The patients of the biological therapy group took the original drug Infliximab – Remicade. The comparison group consisted of 30 healthy volunteers, comparable by sex and age. The analysis of the state of erythrocyte membranes was carried out using a set of physicochemical methods: UV spectroscopy (SF-46m spectrophotometer), high-performance thin-layer reaction paper chromatography, membrane ultrafiltration, erythrocyte NMR spectroscopy on phosphoric (31P) and proton (1H) nuclei. The functional state of the kidneys was evaluated using a dynamic scintigraphic study (with the technemage –Tc-99m).Results. Prolonged use of anticytokine therapy with Infliximab for 10 years in patients with ulcerative colitis, upon reaching deep remission, improves endogenous intoxication, restores the structural and functional characteristics of cell membranes, normalizes cell energy metabolism and does not negatively affect the functional state of the kidneys. 

Withdrawal of immunosuppressant or biologic therapy for patients with quiescent Crohn's disease

BACKGROUND

Crohn's disease (CD) is a chronic, relapsing and remitting disease of the gastrointestinal tract that can cause significant morbidity and disability. Current treatment guidelines recommend early intervention with immunosuppressant or biological therapy in high-risk patients with a severe disease phenotype at presentation. The feasibility of therapeutic de-escalation once remission is achieved is a commonly encountered question in clinical practice, driven by patient and clinician concerns regarding safety, adverse events, cost and national regulations. Withdrawal of immunosuppressant and biologic drugs in patients with quiescent CD may limit adverse events and reduce healthcare costs. Alternatively, stopping these drug therapies may result in negative outcomes such as disease relapse, drug desensitization, bowel damage and need for surgery.

OBJECTIVES

To assess the feasibility and safety of discontinuing immunosuppressant or biologic drugs, administered alone or in combination, in patients with quiescent CD.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase and the Cochrane IBD Group Specialized Register from inception to 19 December 2017. We also searched the reference lists of potentially relevant manuscripts and conference proceedings to identify additional studies.

SELECTION CRITERIA

Randomized controlled trials (RCTs) and prospective cohort studies that followed patients for a minimum duration of six months after drug discontinuation were considered for inclusion. The patient population of interest was adults (> 18 years) with CD (as defined by conventional clinical, endoscopic or histologic criteria) who had achieved remission while receiving immunosuppressant or biologic drugs administered alone or in combination. Patients then discontinued the drug regimen following a period of maintenance therapy of at least six months. The comparison was usual care (i.e. continuation of the drug regimen).

DATA COLLECTION AND ANALYSIS

The primary outcome measure was the proportion of patients who relapsed following discontinuation of immunosuppressant or biologic drugs, administered alone or in combination. Secondary outcomes included: the proportion of patients who responded to the reintroduction of immunosuppressant or biologic drugs, given as monotherapy or combination therapy; the proportion of patients who required surgery following relapse; the proportion of patients who required hospitalization for CD following relapse; the proportion of patients who developed new CD-related complications (e.g. fistula, abscesses, strictures) following relapse; the proportion of patients with elevated biomarkers of inflammation (CRP, fecal calprotectin) in those who stop and those who continue therapy; the proportion of patients with anti-drug antibodies and low serum trough drug levels; time to relapse; and the proportion of patients with adverse events, serious adverse events and withdrawal due to adverse events. For dichotomous outcomes, we calculated the risk ratio (RR) and 95% confidence interval (95% CI). Data were analyzed on an intention-to-treat basis where patients with missing outcome data were assumed to have relapsed. The overall quality of the evidence supporting the primary and secondary outcomes was assessed using the GRADE criteria.

MAIN RESULTS

A total of six RCTs (326 patients) evaluating therapeutic discontinuation in patients with quiescent CD were eligible for inclusion. In four RCTs azathioprine monotherapy was discontinued, and in two RCTs azathioprine was discontinued from a combination therapy regimen consisting of azathioprine with infliximab. No studies of biologic monotherapy withdrawal were eligible for inclusion. The majority of studies received unclear or low risk of bias ratings, with the exception of three open-label RCTs, which were rated as high risk of bias for blinding. Four RCTs (215 participants) compared discontinuation to continuation of azathioprine monotherapy, while two studies (125 participants) compared discontinuation of azathioprine from a combination regimen to continuation of combination therapy. Continuation of azathioprine monotherapy was shown to be superior to withdrawal for risk of clinical relapse. Thirty-two per cent (36/111) of azathioprine withdrawal participants relapsed compared to 14% (14/104) of participants who continued with azathioprine therapy (RR 0.42, 95% CI 0.24 to 0.72, GRADE low quality evidence). However, it is uncertain if there are any between-group differences in new CD-related complications (RR 0.34, 95% CI 0.06 to 2.08, GRADE low quality evidence), adverse events (RR 0.88, 95% CI 0.67 to 1.17, GRADE low quality evidence), serious adverse events (RR 3.29, 95% CI 0.35 to 30.80, GRADE low quality evidence) or withdrawal due to adverse events (RR 2.59, 95% CI 0.35 to 19.04, GRADE low quality evidence). Common adverse events included infections, mild leukopenia, abdominal symptoms, arthralgias, headache and elevated liver enzymes. No differences between azathioprine withdrawal from combination therapy versus continuation of combination therapy were observed for clinical relapse. Among patients who continued combination therapy with azathioprine and infliximab, 48% (27/56) had a clinical relapse compared to 49% (27/55) of patients discontinued azathioprine but remained on infliximab (RR 1.02, 95% CI 0.68 to 1.52, P = 0.32; GRADE low quality evidence). The effects on adverse events (RR 1.11, 95% CI 0.44 to 2.81, GRADE low quality of evidence) or serious adverse events are uncertain (RR 1.00, 95% CI 0.21 to 4.66; GRADE very low quality of evidence). Common adverse events in the combination therapy studies included infections, liver test elevations, arthralgias and infusion reactions.

AUTHORS' CONCLUSIONS

The effects of withdrawal of immunosuppressant therapy in people with quiescent Crohn's disease are uncertain. Low quality evidence suggests that continuing azathioprine monotherapy may be superior to withdrawal for avoiding clinical relapse, while very low quality evidence suggests that there may be no difference in clinical relapse rates between discontinuing azathioprine from a combination therapy regimen, compared to continuing combination therapy. It is unclear whether withdrawal of azathioprine, initially administered alone or in combination, impacts on the development of CD-related complications, adverse events, serious adverse events or withdrawal due to adverse events. Further high-quality research is needed in this area, particularly double-blind RCTs in which biologic therapy or an immunosuppressant other than azathioprine is withdrawn.