Azathioprine dose reduction in inflammatory bowel disease patients on combination therapy: an open-label, prospective and randomised clinical trial

Mechanisms and management of loss of response to anti-TNF therapy for patients with Crohn's disease: 3-year data from the prospective, multicentre PANTS cohort study

BACKGROUND

We sought to report the effectiveness of infliximab and adalimumab over the first 3 years of treatment and to define the factors that predict anti-TNF treatment failure and the strategies that prevent or mitigate loss of response.

METHODS

Personalised Anti-TNF therapy in Crohn's disease (PANTS) is a UK-wide, multicentre, prospective observational cohort study reporting the rates of effectiveness of infliximab and adalimumab in anti-TNF-naive patients with active luminal Crohn's disease aged 6 years and older. At the end of the first year, sites were invited to enrol participants still receiving study drug into the 2-year PANTS-extension study. We estimated rates of remission across the whole cohort at the end of years 1, 2, and 3 of the study using a modified survival technique with permutation testing. Multivariable regression and survival analyses were used to identify factors associated with loss of response in patients who had initially responded to anti-TNF therapy and with immunogenicity. Loss of response was defined in patients who initially responded to anti-TNF therapy at the end of induction and who subsequently developed symptomatic activity that warranted an escalation of steroid, immunomodulatory, or anti-TNF therapy, resectional surgery, or exit from study due to treatment failure. This study was registered with ClinicalTrials.gov, NCT03088449, and is now complete.

FINDINGS

Between March 19, 2014, and Sept 21, 2017, 389 (41%) of 955 patients treated with infliximab and 209 (32%) of 655 treated with adalimumab in the PANTS study entered the PANTS-extension study (median age 32·5 years [IQR 22·1-46·8], 307 [51%] of 598 were female, and 291 [49%] were male). The estimated proportion of patients in remission at the end of years 1, 2, and 3 were, for infliximab 40·2% (95% CI 36·7-43·7), 34·4% (29·9-39·0), and 34·7% (29·8-39·5), and for adalimumab 35·9% (95% CI 31·2-40·5), 32·9% (26·8-39·2), and 28·9% (21·9-36·3), respectively. Optimal drug concentrations at week 14 to predict remission at any later timepoints were 6·1-10·0 mg/L for infliximab and 10·1-12·0 mg/L for adalimumab. After excluding patients who had primary non-response, the estimated proportions of patients who had loss of response by years 1, 2, and 3 were, for infliximab 34·4% (95% CI 30·4-38·2), 54·5% (49·4-59·0), and 60·0% (54·1-65·2), and for adalimumab 32·1% (26·7-37·1), 47·2% (40·2-53·4), and 68·4% (50·9-79·7), respectively. In multivariable analysis, loss of response at year 2 and 3 for patients treated with infliximab and adalimumab was predicted by low anti-TNF drug concentrations at week 14 (infliximab: hazard ratio [HR] for each ten-fold increase in drug concentration 0·45 [95% CI 0·30-0·67], adalimumab: 0·39 [0·22-0·70]). For patients treated with infliximab, loss of response was also associated with female sex (vs male sex; HR 1·47 [95% CI 1·11-1·95]), obesity (vs not obese 1·62 [1·08-2·42]), baseline white cell count (1·06 [1·02-1·11) per 1 × 109 increase in cells per L), and thiopurine dose quartile. Among patients treated with adalimumab, carriage of the HLA-DQA1*05 risk variant was associated with loss of response (HR 1·95 [95% CI 1·17-3·25]). By the end of year 3, the estimated proportion of patients who developed anti-drug antibodies associated with undetectable drug concentrations was 44·0% (95% CI 38·1-49·4) among patients treated with infliximab and 20·3% (13·8-26·2) among those treated with adalimumab. The development of anti-drug antibodies associated with undetectable drug concentrations was significantly associated with treatment without concomitant immunomodulator use for both groups (HR for immunomodulator use: infliximab 0·40 [95% CI 0·31-0·52], adalimumab 0·42 [95% CI 0·24-0·75]), and with carriage of HLA-DQA1*05 risk variant for infliximab (HR for carriage of risk variant: infliximab 1·46 [1·13-1·88]) but not for adalimumab (HR 1·60 [0·92-2·77]). Concomitant use of an immunomodulator before or on the day of starting infliximab was associated with increased time without the development of anti-drug antibodies associated with undetectable drug concentrations compared with use of infliximab alone (HR 2·87 [95% CI 2·20-3·74]) or introduction of an immunomodulator after anti-TNF initiation (1·70 [1·11-2·59]). In years 2 and 3, 16 (4%) of 389 patients treated with infliximab and 11 (5%) of 209 treated with adalimumab had adverse events leading to treatment withdrawal. Nine (2%) patients treated with infliximab and two (1%) of those treated with adalimumab had serious infections in years 2 and 3.

INTERPRETATION

Only around a third of patients with active luminal Crohn's disease treated with an anti-TNF drug were in remission at the end of 3 years of treatment. Low drug concentrations at the end of the induction period predict loss of response by year 3 of treatment, suggesting higher drug concentrations during the first year of treatment, particularly during induction, might lead to better long-term outcomes. Anti-drug antibodies associated with undetectable drug concentrations of infliximab, but not adalimumab, can be predicted by carriage of HLA-DQA1*05 and mitigated by concomitant immunomodulator use for both drugs.

FUNDING

Guts UK, Crohn's and Colitis UK, Cure Crohn's Colitis, AbbVie, Merck Sharp and Dohme, Napp Pharmaceuticals, Pfizer, and Celltrion Healthcare.

Combination treatment of inflammatory bowel disease: Present status and future perspectives

The treatment of patients with inflammatory bowel disease (IBD), especially those with severe or refractory disease, represents an important challenge for the clinical gastroenterologist. It seems to be no exaggeration to say that in these patients, not only the scientific background of the gastroenterologist is tested, but also the abundance of "gifts" that he should possess (insight, intuition, determination, ability to take initiative, etc.) for the successful outcome of the treatment. In daily clinical practice, depending on the severity of the attack, IBD is treated with one or a combination of two or more pharmaceutical agents. These combinations include not only the first-line drugs (e.g., mesalazine, corticosteroids, antibiotics, etc) but also second- and third-line drugs (immunosuppressants and biologic agents). It is a fact that despite the significant therapeutic advances there is still a significant percentage of patients who do not satisfactorily respond to the treatment applied. Therefore, a part of these patients are going to surgery. In recent years, several small-size clinical studies, reviews, and case reports have been published combining not only biological agents with other drugs (e.g., immunosuppressants or corticosteroids) but also the combination of two biological agents simultaneously, especially in severe cases. In our opinion, it is at least a strange (and largely unexplained) fact that we often use combinations of drugs in a given patient although studies comparing the simultaneous administration of two or more drugs with monotherapy are very few. As mentioned above, there is a timid tendency in the literature to combine two biological agents in severe cases unresponsive to the applied treatment or patients with severe extraintestinal manifestations. The appropriate dosage, the duration of the administration, the suitable timing for checking the clinical and laboratory outcome, as well as the treatment side-effects, should be the subject of intense clinical research shortly. In this editorial, we attempt to summarize the existing data regarding the already applied combination therapies and to humbly formulate thoughts and suggestions for the future application of the combination treatment of biological agents in a well-defined category of patients. We suggest that the application of biomarkers and artificial intelligence could help in establishing new forms of treatment using the available modern drugs in patients with IBD resistant to treatment.

Withdrawal of Immunomodulators or TNF Antagonists in Patients With Inflammatory Bowel Diseases in Remission on Combination Therapy: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Withdrawal of immunomodulators (IMMs) or tumor necrosis factor (TNF) antagonists in patients with inflammatory bowel diseases (IBDs) in remission on combination therapy is attractive. We evaluated the efficacy and safety of (1) IMM, or (2) TNF antagonist withdrawal in patients with IBD in sustained remission on combination therapy.

METHODS

Through a systematic review till March 31, 2023, we identified randomized controlled trials (RCTs) that compared the efficacy and safety of IMM or TNF antagonist withdrawal vs continued combination therapy, in patients with IBD in sustained corticosteroid-free clinical remission for >6 months on combination therapy. Primary outcome was risk of relapse and serious adverse events at 12 months. We conducted meta-analysis to calculate relative risk (RR) and 95% confidence interval (CI) and used Grading of Recommendations Assessment, Development and Evaluation (GRADE) to appraise certainty of evidence.

RESULTS

We identified 8 RCTs with 733 patients (77% with Crohn's disease, 91% on infliximab-based combination therapy). On meta-analysis of 5 RCTs, there was no difference in the risk of relapse between patients with IMM withdrawal (continued TNF antagonist monotherapy) vs continued combination therapy (16.8% vs 14.9%; RR, 1.15; 95% CI, 0.75-1.76) without heterogeneity (low certainty of evidence). TNF antagonist withdrawal (continued IMM monotherapy) was associated with 2.4-times higher risk of relapse compared with continuing combination therapy (31.5% vs 11.2%; RR, 2.35; 95% CI, 1.38-4.01), with minimal heterogeneity (low certainty of evidence). There was no difference in the risk of serious adverse events with IMM or TNF antagonist withdrawal vs continued combination therapy.

CONCLUSIONS

In patients with IBD in sustained corticosteroid-free clinical remission for >6 months on combination therapy, de-escalation with TNF antagonist withdrawal, but not IMM withdrawal, was associated with an increased risk of relapse.

A Review of Therapeutic Drug Monitoring in Patients with Inflammatory Bowel Disease Receiving Combination Therapy

Background: Inflammatory Bowel Disease (IBD) impacts millions worldwide, presenting a major challenge to healthcare providers and patients. The advent of biologic therapies has enhanced the prognosis, but many patients exhibit primary or secondary non-response, underscoring the need for rigorous monitoring and therapy optimization to improve outcomes. Objective: This narrative review seeks to understand the role of therapeutic drug monitoring (TDM) in optimizing treatment for IBD patients, especially for those on combination therapies of biologics and immunomodulators. Methods: A comprehensive synthesis of the current literature was undertaken, focusing on the application, benefits, limitations, and future directions of TDM in patients receiving a combination of biologic therapies and immunomodulators. Results: While biological therapies have improved outcomes, rigorous monitoring and therapy optimization are needed. TDM has emerged as a pivotal strategy, enhancing outcomes cost-effectively while reducing adverse events. While most data pertain to monotherapies, TDM's applicability also extends to combination therapy. Conclusion: TDM plays a crucial role in the treatment optimization of IBD patients on combination therapies. Further research is needed to fully understand its potential and limitations in the broader context of IBD management.

Combination Therapy With Immunomodulators Improves the Pharmacokinetics of Infliximab But Not Vedolizumab or Ustekinumab

BACKGROUND AND AIMS

The aim of this study was to assess how 6-thioguanine nucleotide (6-TGN) levels and use of oral methotrexate relate to the pharmacokinetics of biologics.

METHODS

This was a prospective cohort study including patients with inflammatory bowel diseases on maintenance doses of infliximab, vedolizumab, or ustekinumab on monotherapy or combination with a thiopurine or oral methotrexate. We collected 6-TGN concentrations, biomarker levels, and clinical and endoscopic disease activity. The primary outcomes were infliximab, vedolizumab, and ustekinumab concentrations as well as anti-drug antibodies (ADAs).

RESULTS

A total of 369 patients were recruited (113 infliximab, 133 vedolizumab, and 123 ustekinumab). Patients with 6-TGN levels ≥146 pmol per 8 × 108 red blood cells (RBCs), and those receiving combination therapy with thiopurine or oral methotrexate had significantly higher infliximab concentrations when compared with monotherapy (median levels of 17.4 μg/mL on thiopurine with 6-TGN ≥146 pmol per 8 × 108 RBCs, 17.1 on methotrexate, and 3.9 on infliximab monotherapy; P = .001 for both comparisons). However, there was no association between the use of immunomodulators and 6-TGN concentrations with vedolizumab (median levels of 8.8 on thiopurine with 6-TGN ≥152 pmol per 8 × 108 RBCs, 6.8 on methotrexate, and 10.5 on vedolizumab monotherapy; P > .05 for both comparisons) or ustekinumab median concentrations (median levels of 5.0 on thiopurine with 6-TGN ≥154 pmol per 8 × 108 RBCs, 5.2 on methotrexate and 7.0 on ustekinumab monotherapy; P > .05 for both comparisons). Fourteen (12%) patients had anti-infliximab antibodies, while 1 patient had ADAs in each of the other drug cohorts.

CONCLUSIONS

Achieving higher 6-TGN levels or the use of methotrexate improved the pharmacokinetics of infliximab. Conversely, these data do not support the use of combination therapy to augment pharmacokinetics with vedolizumab or ustekinumab.

Association between 6-thioguanine nucleotide levels and preventing production of antibodies to infliximab in patients with inflammatory bowel disease

OBJECTIVE

Combination therapy with infliximab and a thiopurine has been shown to be more effective than monotherapy in patients with inflammatory bowel disease (IBD). The therapeutic efficacy of thiopurines is correlated with 6-thioguanine (6-TGN) levels between 235 and 450 pmol/8×108 erythrocytes. The primary aim of the study was to investigate the association between 6-TGN levels and inhibition prevention of the production of antibodies to infliximab (ATI).

DESIGN

We performed a retrospective review of the medical records of patients being treated with infliximab for IBD at University Hospitals Bristol NHS Foundation Trust. Demographic and biochemical data were extracted, alongside thiopurine metabolite levels, trough levels of infliximab and the presence of ATI. χ2 tests were used to investigate the association between 6-TGN levels and prevention of ATI. Logistic regression was used to compare the odds of prevented ATI between those with a 6-TGN level between 235 and 450 pmol/8×108 erythrocytes, those with a 6-TGN level outside of this range, and the baseline group who were on infliximab monotherapy.

RESULTS

Data were extracted for 100 patients. Six of 32 patients with a 6-TGN level between 235 and 450 pmol/8×108 erythrocytes developed ATI (18.8%) compared with 14 out of 22 (63.6%) patients with a 6-TGN outside of this range and 32 out of 46 (69.6%) patients on monotherapy (p=0.001). The OR (95% CI) for prevented ATI in those with a 6-TGN between 235 and 450 pmol/8×108 erythrocytes compared with a 6-TGN outside of this range was 7.6 (2.2, 26.3) (p=0.001) and compared with monotherapy was 9.9 (3.3, 29.4) (p=0.001).

CONCLUSION

6-TGN levels between 235 and 450 pmol/8×108 erythrocytes prevented production of ATI. This supports therapeutic drug monitoring to help guide treatment and maximise the beneficial effects of combination therapy for patients with IBD.

Exit strategies in inflammatory bowel disease: Looking beyond anti-tumor necrosis factors

The long-term management of patients with inflammatory bowel disease (IBD) is still a matter of debate, and no clear guidelines have been issued. In clinical practice, gastroenterologists often have to deal with patients in prolonged remission after immunomodulatory or immunosuppressive therapies. When planning an exit strategy for drug withdrawal, the risk of disease relapse must be balanced against the risk of drug-related adverse events and healthcare costs. Furthermore, there is still a dearth of data on the withdrawal of novel biologics, such as the anti-α4β7 integrin antibody (vedolizumab) and anti-IL12/23 antibody (ustekinumab), as well as the small molecule tofacitinib. Models for estimating the risk of disease relapse and the efficacy of retreatment should be evaluated according to the patient's age and IBD phenotype. These models should guide clinicians in programming a temporary drug withdrawal after discussing realistic outcomes with the patient. This would shift the paradigm from an exit strategy to a holiday strategy.

Recent Advances in the Optimization of Anti-TNF Treatment in Patients with Inflammatory Bowel Disease

Despite the evolution in inflammatory bowel disease (IBD) management during the last 20 years owing to the advent of new advanced therapies, anti-TNF agents still remain the cornerstone of therapy for both Crohn's disease and ulcerative colitis. However, this does not only secure favorable outcomes for patients considering the progressive disease character and the high likelihood of primary or secondary loss of response. Therefore, trying to reach a better treatment approach and maximize the benefits anti-TNF agents offer, optimization strategies should be examined. It has been indicated that optimizing treatment with anti-TNF enhances drug efficacy and has been associated with improved disease outcomes and a complication-free disease course. From this perspective, we aim to provide an overview of currently available data and recent advances in the practices of anti-TNF treatment optimization. Special focus has been given to the role of therapeutic drug monitoring (TDM), as well as the utility of combining anti-TNF with an immunomodulator and the treat-to-target approach.

De-escalation of Therapy in Patients with Quiescent Inflammatory Bowel Disease

Inflammatory bowel disease is a chronic disease of unknown origin that requires long-term treatment. The optical duration of maintenance treatment once remission has been achieved remains unclear. When discussing a de-escalation strategy, not only the likelihood of relapse but also, the outcome of retreatment for relapse after de-escalation should be considered. Previous evidence has demonstrated controversial results for risk factors for relapse after de-escalation due to the various definitions of remission and relapse. In fact, endoscopic or histologic remission has been suggested as a treatment target; however, it might not always be indicative of a successful drug withdrawal. For better risk stratification of relapse after de-escalation, it may be necessary to evaluate both the current and previous treatments. Following de-escalation, biomarkers should be closely monitored. In addition to the risk of relapse, a comprehensive understanding of the overall outcome, such as the long-term safety, patient quality of life, and impact on healthcare costs, is necessary. Therefore, a shared decision-making with patients on a case-by-case basis is imperative.

Immunomodulator comedication promotes the reversal of anti-drug antibody-mediated loss of response to anti-TNF therapy in inflammatory bowel disease

PURPOSE

Loss of therapeutic response (LOR) due to anti-drug antibodies (ADA) against tumor necrosis factor (TNF) inhibitors is common in patients with inflammatory bowel disease (IBD). We aimed to investigate whether immunomodulator comedication can reverse the immunogenic LOR to TNF inhibitors in IBD.

METHODS

In this real-world retrospective cohort study, 123 IBD patients with neutralizing ADA to infliximab or adalimumab and concomitant subtherapeutic trough levels were screened for clinical LOR. Subsequent ADA and trough level measurements and clinical outcomes were analyzed for patients who received either immunomodulator comedication or dose intensification of infliximab or adalimumab to overcome LOR.

RESULTS

Following immunogenic LOR, the initial anti-TNF regimen was optimized in 33 patients. In univariable and multivariable logistic regression analyses, immunomodulator comedication was identified as the crucial factor for regaining clinical remission and ADA clearance. Detectable trough levels (≥ 0.98 or ≥ 1.00 mg/L, respectively) had optimal predictive performance for both endpoints in receiver operating characteristics curves [area under the curve 0.86 (95% confidence interval 0.68-1.00) for regaining clinical remission, 0.87 (0.71-1.00) for ADA clearance]. Furthermore, 11/20 patients (55%) on a comedication with azathioprine or methotrexate and 2/13 patients (15%) receiving anti-TNF dose intensification exclusively (P = 0.032) exhibited ADA elimination, regain of therapeutic trough levels, and clinical remission. Regain of clinical remission alone was achieved in 17/20 (85%) patients receiving comedication and 2/13 (15%) patients receiving anti-TNF dose intensification (P = 1.6 × 10-4).

CONCLUSION

Immunogenic LOR to infliximab or adalimumab in IBD can be successfully reversed using immunomodulator comedication.

Treatment escalation and de-escalation decisions in Crohn's disease: Delphi consensus recommendations from Japan, 2021

BACKGROUND

We aimed to develop criteria for treatment intensification in patients with (1) luminal Crohn's disease (CD), (2) CD with perianal disease and/or fistula, (3) CD with small bowel stenosis, (4) in the postoperative setting, and (5) for discontinuing or reducing the dose of treatment in patients with CD.

METHODS

PubMed and Embase were searched for studies published since 1998 which may be relevant to the five defined topics. Results were assessed for relevant studies, with preference given to data from randomized, controlled studies. For each question, a core panel of 12 gastroenterologists defined the treatment target and developed statements, based on the literature, current guidelines, and relevant additional studies. The evidence supporting each statement was graded using the Oxford Centre for Evidence-Based Medicine: Levels of Evidence (March 2009). A modified Delphi process was used to refine statements and gain agreement from 54 Japanese specialists at in-person and online meetings conducted between October 2020 and April 2021.

RESULTS

Seventeen statements were developed for treatment intensification in luminal CD (targeting endoscopic remission), six statements for treatment intensification in perianal/fistulizing CD (targeting healing of perianal lesions and complete closure of the fistula), six statements for treatment intensification in CD with small bowel stenosis (targeting resolution of obstructive symptoms), seven statements for treatment intensification after surgery (targeting endoscopic remission), and five statements for discontinuing or reducing the dose of treatment in patients with CD.

CONCLUSIONS

These statements provide guidance on how and when to intensify or de-intensify treatment for a broad spectrum of patients with CD.

Azathioprine Withdrawal Is Cost-Effective in Patients with Crohn's Disease in Remission on Infliximab and Azathioprine

BACKGROUND

In Crohn's disease, combination therapy with infliximab and azathioprine is more effective than either drug alone but is associated with a higher risk of therapy-related complications. Though therapy de-escalation can reduce risks and save costs, it is associated with a risk of Crohn's disease relapse.

AIMS

We aimed to study the cost-effectiveness of de-escalation strategies in Crohn's disease patients in remission on infliximab and azathioprine.

METHODS

We constructed a decision tree with Markov models for continuation of infliximab and azathioprine, discontinuation of azathioprine followed by its re-introduction in case of relapse, discontinuation of azathioprine followed by infliximab dose intensification without azathioprine reintroduction in case of relapse and discontinuation of infliximab. Third-party payers' perspective with a willingness-to-pay threshold of $100,000/quality-adjusted life years was used. Markov cycle length was 3 months, and the study period was 5 years. A 35-year-old patient with Crohn's disease in clinical remission on azathioprine 150 mg daily and infliximab 5 mg/kg every 8 weeks was used for base-case analysis.

RESULTS

Azathioprine withdrawal followed by its reintroduction upon relapse was the dominant strategy as it was the most effective and least expensive approach on base-case analysis. It was also cost-effective in 99.3% of Monte Carlo trial simulations. AZA withdrawal without IFX dose intensification upon relapse was the least effective and the most expensive strategy.

CONCLUSION

Azathioprine withdrawal is the most effective and least costly de-escalation strategy in CD patients in remission on combination therapy if AZA re-introduction is performed upon CD relapse.

Combination therapy in inflammatory bowel disease: Current evidence and perspectives

BACKGROUND AND OBJECTIVE

Inflammatory Bowel Diseases (IBD) are chronic nonspecific intestinal inflammatory diseases with a relapsing-remitting course, including Ulcerative Colitis (UC) and Crohn's Disease (CD). Combination therapy has been proposed as a strategy to enhance treatment efficacy in IBD. The aim of this study is to summarize current evidence and perspectives on combination therapies in IBD.

METHODS

Electronic databases such as PubMed, Ovid Embase, Medline, and Cochrane CENTRAL were searched to identify relevant studies.

RESULTS

Current evidence supports that the combination of infliximab and thiopurines is more effective than monotherapy in inducing and maintaining remission in IBD. Data on the combination of other biological agents such as adalimumab, vedolizumab, ustekinumab, and immunosuppressors is lacking or showed conflicting results. Vedolizumab seems a potentially effective maintenance regimen after calcineurin inhibitors-based rescue therapy in acute severe ulcerative colitis (ASUC). Dual Targeted Therapy, which is the combination of two biological agents and/or small molecules, might be a reasonable choice in patients with concomitant IBD and extraintestinal manifestations, or in patients with medical-refractory IBD who lack valid alternatives. Some safety concerns such as adverse events (serious and opportunistic infections) and malignancies (lymphoma and nonmelanoma skin cancer) were raised in combination therapies.

CONCLUSIONS

Combination therapies seem to be effective in some IBD patients such as refractory IBD patients or patients with extraintestinal manifestations, but it might be associated with an increased risk of adverse events and malignancies.

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.

Decreased risk of treatment failure with vedolizumab and thiopurines combined compared with vedolizumab monotherapy in Crohn's disease

OBJECTIVE

While infliximab combined to thiopurines is more effective than infliximab monotherapy in patients with Crohn's disease (CD) and UC, the impact of adding thiopurines to vedolizumab remains controversial. We emulated two target trials comparing the effectiveness of combination therapy versus vedolizumab monotherapy in CD and UC.

DESIGN

Based on two US and the French nationwide healthcare databases, patients with CD and UC who initiated vedolizumab were identified. The study methodology, including confounding adjustment and outcome definitions, were previously validated in successful emulations of the SONIC and SUCCESS trials. Risk ratios for treatment failure based on hospitalisation or surgery related to disease activity, treatment switch, or prolonged corticosteroids use, were estimated after 1:1 propensity score (PS) matching.

RESULTS

Among a total of 10 299 vedolizumab users, 804 CD and 1088 UC pairs of combination therapy versus vedolizumab monotherapy users were PS matched. Treatment failure occurred at week 26 in 236 (29.3%) and 376 (34.3%) patients with CD and at week 16 in 236 (21.7%) and 263 (24.2%) patients with UC initiating combination therapy and vedolizumab monotherapy, respectively. The risk of treatment failure was decreased with combination therapy compared with vedolizumab monotherapy in CD (RR 0.85, 95% CI: 0.74 to 0.98) and to a lesser extent in UC (RR 0.90, 95% CI: 0.77 to 1.05). Findings were consistent across databases.

CONCLUSION

Using validated methodologies, combination therapy with vedolizumab and thiopurines was associated with lower treatment failure compared with vedolizumab monotherapy in CD but not UC across the USA and France.

Use of biologics and small molecule drugs for the management of moderate to severe ulcerative colitis: IG-IBD technical review based on the GRADE methodology

The increased knowledge on the biological mechanisms underlying ulcerative colitis (UC) has triggered an advance in drug development, drastically changing the therapeutic landscape. Several biologics and small-molecule drugs have been regulatory approved (i.e., infliximab, adalimumab, golimumab, vedolizumab, ustekinumab and tofacitinib), and frequently pose clinical dilemmas: physicians need to know how these therapies can be used to optimize patient-important outcomes. Adhering to the "Grading of Recommendations Assessment, Development and Evaluation" (GRADE) methodology, this technical review systematically searched and identified the evidence, synthesized it using rigorous meta-analytic methodology, appraised its quality, and concisely presented it in a transparent way, forming the basis for developing clinical recommendations on the use of biologics and small-molecule drugs in adult patients with UC.

Optimizing Therapies Using Therapeutic Drug Monitoring: Current Strategies and Future Perspectives

Therapeutic drug monitoring (TDM) has emerged as a strategy for treatment optimization in inflammatory bowel diseases to maximize benefit and to reach more stringent, objective end points. Optimal drug concentrations in inflammatory bowel disease vary according to treatment target, disease phenotype, inflammatory burden, and timing of sampling during the treatment cycle. This review provides an update on TDM with biologic and oral small molecules, evaluates the role of reactive vs proactive TDM, and identifies the gaps in current evidence. In the future, adaptations to how we use TDM may contribute further to the goal of personalized treatment in patients with IBD.

NUDT15 intermediate metabolisers are associated with lower loss of response in paediatric Crohn's disease patients treated by combination treatment with infliximab and azathioprine

BACKGROUND

NUDT15 polymorphisms are associated with leukopenia during treatment with thiopurines. However, data regarding its effect on treatment outcomes are scarce.

AIMS

To investigate the outcomes between NUDT15 normal and intermediate metabolisers in paediatric patients with Crohn's disease (CD) treated with a combination therapy of infliximab (IFX) and azathioprine (AZA).

METHODS

In this retrospective observational study, 143 patients categorised into the NUDT15 normal and intermediate metaboliser groups were compared based on clinical remission (CR), biochemical remission (BR), mucosal healing (MH) at 1 year treatment, IFX trough levels (TLs), antibodies to IFX (ATIs), 6-thioguanine nucleotide (6-TGN) levels, loss of response (LOR) and IFX durability.

RESULTS

No significant differences were observed between the groups in CR, BR, MH at 1 year, whereas IFX TLs and ATIs and 6-TGN levels were comparable. However, LOR (6.5% vs 27.7%, P = 0.025) was significantly lower and IFX durability significantly higher (96.8% vs 80.4% P = 0.027) in the intermediate group. Multivariable Cox proportional hazard regression analysis showed that ATI positivity (hazard ratio (HR): 4.76, 95% CI: 2.25-10.07, P < 0.001) and the NUDT15 metaboliser group was associated with LOR (HR: 0.18, 95% CI: 0.04-0.76, P = 0.019). The Kaplan-Meier survival curves showed that the LOR-free survival rate was significantly lower in normal metabolisers (log-rank test P = 0.009).

CONCLUSION

NUDT15 intermediate metabolisers were associated with lower LOR in paediatric patients with CD treated with IFX and AZA combination therapy. This finding may partially explain the longer durability of IFX in Korean children than their counterparts in Western countries.

Discontinuation of Azathioprine could be considered in pediatric patients with Crohn's disease who have sustained clinical and deep remission

Few studies have demonstrated treatment strategies about the duration and cessation of medications in patients with Crohn's disease (CD). We investigated factors affecting clinical relapse after infliximab (IFX) or azathioprine (AZA) withdrawal in pediatric patients with CD on combination therapy. Pediatric patients with moderate-to-severe CD receiving combination therapy were analyzed retrospectively and factors associated with clinical relapse were investigated. Discontinuation of IFX or AZA was performed in patients who sustained clinical remission (CR) for at least two years and achieved deep remission. A total of 75 patients were included. Forty-four patients (58.7%) continued with combination therapy and 31 patients (41.3%) discontinued AZA or IFX (AZA withdrawal 10, IFX withdrawal 15, both withdrawal 6). Cox proportional-hazards regression and statistical internal validation identified three factors associated with clinical relapse: IFX cessation (hazard ratio; HR 2.982, P = 0.0081), IFX TLs during maintenance therapy (HR 0.581, P = 0.003), 6-thioguanine nucleotide (6-TGN) level (HR 0.978, P < 0.001). However, AZA cessation was not associated with clinical relapse (P = 0.9021). Even when applied in pediatric patients who met stringent criteria, IFX cessation increased the relapse risk. However, withdrawal of AZA could be contemplated in pediatric patients with CD who have sustained CR for at least 2 years and achieved deep remission.

The efficacy of immunomodulators in the prevention and suppression of anti-drug antibodies to anti-tumor necrosis factor therapy in inflammatory bowel disease

The development of biological agents against tumor necrosis factor (TNF) has revolutionized the management of inflammatory bowel disease (IBD), frequently achieving induction and maintenance of remission in both ulcerative colitis and Crohn's disease. However, a loss of response due to the development of anti-drug antibodies (ADA) is seen annually in approximately 20% of IBD patients receiving anti-TNF therapy. Current evidence suggests that the use of immunomodulators (IMM), such as thiopurines (azathioprine and 6-mercaptopurine) or methotrexate, may prevent or suppress ADA formation. In this article, we present a comprehensive review of the available literature regarding the efficacy of IMM in the prevention and suppression of ADA development to anti-TNF therapy in patients with IBD.

Impact of treatment with immunomodulators and tumour necrosis factor antagonists on the incidence of infectious events in patients with inflammatory bowel disease

BACKGROUND

Corticosteroids, immunomodulators (IM) and tumour necrosis factor antagonists (anti-TNF) are commonly used in the treatment of inflammatory bowel disease (IBD) but they also supress the defence against infectious disease. The aim of this study was to analyse the incidence of infectious events in patients with IBD and the association to concomitant medical therapy.

METHODS

We performed a retrospective medical chart review of patients with IBD aged 18-65 years included in the Swedish Registry of Inflammatory Bowel Disease in the catchment area of Umeå University Hospital, Sweden. Data were collected from the period 01 January 2006, to 31 January 2019. An infectious event was defined as an outpatient prescription of antimicrobials or a positive diagnostic test for infection.

RESULTS

During a period of 5,120 observation-years, we observed 1,394 events in 593 patients. The mean number of infectious events per 100 person-years was 27.2 (standard deviation [SD]: 0.46). There were no differences in mean incidence rates between patients treated with no immunosuppression (23.0 events per 100 person-years, SD: 50.4), patients treated with IM monotherapy (27.6 events per 100 person-years, SD: 49.9), patients treated with anti-TNF monotherapy (34.3 events per 100 person-years, SD: 50.1) and patients on combination therapy (22.5 events per 100-person-years, SD: 44.2). In a multivariate logistic regression, female gender (adjusted odds ratio [AOR]: 2.24; 95% confidence interval [CI]: 1.49-3.37) and combination therapy (AOR: 3.46; 95% CI: 1.52-7.85) were associated with higher risks of infection (>32 events per 100 person years). Also, patients treated with any immunosuppression treatment for 25-75% (AOR: 2.29; 95% CI: 1.21-4.34) and for >75% (AOR: 1.93; 95% CI: 1.19-3.12) of the observation period were at higher risks compared to patients treated with immunosuppression <25% of the observation period.

CONCLUSION

We observed no significant difference in risk for infections between patients on monotherapy with IM or anti-TNF and patients with low use of immunosuppression, but there was a significant risk for combination therapy.

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.

Thiopurines: Use them or lose them? International survey on current and future use of thiopurines in inflammatory bowel disease

BACKGROUND AND AIMS

The role of thiopurines in therapeutic algorithms of Crohn's disease (CD) and Ulcerative colitis (UC) is being questioned. This work aimed to investigate current practice and future perspectives of Inflammatory Bowel Disease (IBD) physicians regarding the efficacy, safety, and role of precision medicine with thiopurines in IBD.

METHODS

A 29-questions web-based survey was developed and distributed to IBD physicians worldwide.

RESULTS

We collected the complete answers of 408 physicians from 50 countries. Most participants were experienced physicians in IBD; 26.0% met our definition of "IBD expert". Four physicians reported to not use thiopurines in clinical practice. Most respondents used thiopurines in monotherapy and in combination therapy, both in CD and UC. Respondents tended to consider thiopurines as drugs with a good safety profile, with the agreement of 61.5% of the overall cohort. A minority of physicians (~6%) considered that thiopurines will not be used in the future in IBD patients, while 57.8% believed that these drugs will still be used, in mono and combination therapy.

CONCLUSION

Despite the many emerging treatments in IBD, according to the beliefs of most physicians surveyed, thiopurines will still be an important part of the treatment algorithm of both CD and UC.

Anti-Drug Antibody Formation Against Biologic Agents in Inflammatory Bowel Disease: A Systematic Review and Meta-Analysis

BACKGROUND AND AIMS

Immunogenicity with formation of anti-drug antibodies (ADA) to biologics is an important reason for treatment failure in inflammatory bowel disease (IBD). Our aim was to assess the rate of ADA, the effect of combination therapy with immunomodulators on ADA and the influence of ADA on efficacy and safety of biologics for IBD treatment.

METHODS

MEDLINE, Embase and Cochrane Central Register of Controlled Trials (CENTRAL) were searched from inception to April 2020 for trials of biologics that assessed immunogenicity. The overall certainty of evidence was evaluated using Grading of Recommendations, Assessment, Development and Evaluations (GRADE). The primary outcome was rate of ADA. Secondary outcomes included efficacy and safety outcomes among patients with detectable versus undetectable ADA. For dichotomous outcomes, pooled risk ratios (RR) and 95% confidence intervals (CI) were calculated.

RESULTS

Data from 68 studies were analyzed and 33 studies (5850 patients) were included in the meta-analysis. Pooled ADA rates for biologic monotherapy were 28.0% for infliximab, 7.5% for adalimumab, 3.8% for golimumab, 10.9% for certolizumab, 6.2% for ustekinumab and 16.0% for natalizumab. Pooled ADA rates were 8.4% for vedolizumab and 5.0% for etrolizumab for combo- and monotherapy combined. In all biologics, ADA rates were underestimated by use of drug-sensitive ADA assays and higher dose and/or frequency. ADA rate was significantly reduced in patients treated with combination therapy for infliximab (RR 0.52; 95% CI 0.44-0.62), adalimumab (RR 0.31; 95% CI 0.14-0.69), golimumab (RR 0.29; 95% CI 0.10-0.83), certolizumab pegol (RR 0.30; 95% CI 0.14-0.67) and natalizumab (RR 0.20; 95% CI 0.11-0. 39). ADA to infliximab were associated with lower clinical response rates (RR 0.75; 95% CI 0.61-0.91) and higher rates of infusion reactions (RR 2.36; 95% CI 1.85-3.01).

CONCLUSIONS

Differences in analytical methods to detect ADA hamper comparison of true ADA rates across biologics in IBD. Use of combination therapy with immunomodulators appeared to reduce ADA positivity for most biologics. For infliximab, ADA were associated with reduced drug efficacy and increased adverse events.

A potential pathogenic association between periodontal disease and Crohn's disease

Oral conditions are relatively common in patients with inflammatory bowel disease (IBD). However, the contribution of oral maladies to gut inflammation remains unexplored. Here, we investigated the effect of periodontitis on disease phenotypes of patients with IBD. In all, 60 patients with IBD (42 with ulcerative colitis [UC] and 18 with Crohn’s disease [CD]) and 45 healthy controls (HCs) without IBD were recruited for this clinical investigation. The effects of incipient periodontitis on the oral and gut microbiome as well as IBD characteristics were examined. In addition, patients were prospectively monitored for up to 12 months after enrollment. We found that, in both patients with UC and those with CD, the gut microbiome was significantly more similar to the oral microbiome than in HCs, suggesting that ectopic gut colonization by oral bacteria is increased in patients with IBD. Incipient periodontitis did not further enhance gut colonization by oral bacteria. The presence of incipient periodontitis did not significantly affect the clinical outcomes of patients with UC and CD. However, the short CD activity index increased in patients with CD with incipient periodontitis but declined or was unchanged during the study period in patients without periodontitis. Thus, early periodontitis may associate with worse clinically symptoms in some patients with CD.

Evolving Role of Thiopurines in Inflammatory Bowel Disease in the Era of Biologics and New Small Molecules

In recent years, with the increasing availability of biologic therapies and due to safety concerns, the role of thiopurines in the management of inflammatory bowel disease has been questioned. While acknowledging that the benefit/risk ratio of biologic therapies is very high, they are expensive and are not required by a majority of patients. Therefore, thiopurines do retain an important role as steroid-sparing and maintenance agents when used as monotherapy, and in combination therapy with biologics due to their clinical and pharmacokinetic optimization of anti-tumor necrosis factor agents in particular. Safety concerns with thiopurines are real but also relatively rare, and with careful pre-treatment screening and ongoing monitoring thiopurine benefits outweigh risks in the majority of appropriately selected patients. Measurement of newer pharmacogenomic markers such as nudix hydrolase 15 (NUDT15), when combined with knowledge of existing known mutations (e.g., thiopurine S-methyltransferase-TPMT), will hopefully minimize the risk of potentially life-threatening leukopenia by allowing for pre-treatment dosing stratification. Further optimization of thiopurine dosing via measurement of thiopurine metabolites should be performed routinely and is superior to weight-based dosing. The association of thiopurines with malignancies including lymphoproliferative disorders needs to be recognized in all patients and individualized in each patient. The decrease in lymphoma risk after thiopurine cessation provides an incentive for thiopurine de-escalation in appropriate patients after a period of prolonged deep remission. This review will summarize the current role of thiopurines in inflammatory bowel disease management and provide recommendations for commencing and monitoring therapy, and when to consider de-escalation.

Adding Thiopurine After Loss of Response to Infliximab Versus Early Combination in Treating Crohn's Disease: A Retrospective Study

BACKGROUND

Although combining thiopurine with infliximab (IFX) is considered to improve the clinical efficacy of IFX when treating Crohn's disease (CD), it also increases the risk of adverse events (AEs). We compared the efficacy and safety of delayed thiopurine addition after loss of response (LOR) to IFX with the efficacy and safety of an earlier combination of thiopurine and IFX.

METHODS

This retrospective study analyzed patients with CD who started IFX as a first-line biologic at Kyushu University Hospital between June 2002 and July 2018. Patients were assigned to either the early-combination (EC) group, who started IFX and thiopurine simultaneously, or the late-combination (LC) group, who were treated with IFX alone until they developed LOR. We compared the cumulative IFX continuation rates and AE incidence between the two groups.

RESULTS

One hundred seventy-six patients were enrolled in this study; 49 were enrolled in the EC group, and 127 were enrolled in the LC group. Disease activity at baseline did not significantly differ between the groups, nor did the cumulative IFX continuation rates differ between the groups (P = 0.30); however, the AE rate was significantly higher in the EC group than in the LC group (38.7% vs. 21.2%; P = 0.02). The severe AE rate was also higher in the EC group than in the LC group (18.3% vs 3.1%; P = 0.001).

CONCLUSION

Considering the risk-benefit balance, delayed addition of thiopurine after LOR to IFX might be an alternative strategy when using IFX to treat CD.

TNF-Alpha Blockers in Inflammatory Bowel Diseases: Practical Recommendations and a User's Guide: An Update

BACKGROUND

Anti-tumour necrosis factor-alpha (anti-TNF) antagonists have been the mainstay in the treatment of inflammatory bowel diseases (IBDs) for over 20 years.

SUMMARY

This review article aimed to provide an update on recent advances in TNF antagonist therapy for IBDs. Key Messages: Their position in the treatment algorithm has evolved to "rapid step-up therapy" or "top-down therapy" according to disease severity and patients' characteristics. Limitations of anti-TNF antagonists include loss of response in up to 30-50% of patients with or without the development of antibodies. Therapeutic drug monitoring should provide a tailored, personalized approach to this scenario. Recently, biosimilar agents have been approved for IBDs and are considered equivalent in efficacy to the originator.

Thiopurines in Inflammatory Bowel Disease. How to Optimize Thiopurines in the Biologic Era?

Thiopurines have been a cornerstone in the treatment of inflammatory bowel disease (IBD). Although they have been used for more than 50 years, there are still some unsolved issues about their efficacy and, also, some safety concerns, mainly the risk of myelosuppression and life-threatening lymphoproliferative disorders. Furthermore, the development of biological therapy raises the question whether there is still a role for thiopurines in the IBD treatment algorithm. On the other hand, limited cost and wide availability make thiopurines a reasonable option in settings of limited resources and increasing prevalence of IBD. In fact, there is a growing interest in optimizing thiopurine therapy, since pharmacogenomic findings suggest that a personalized approach based on the genotyping of some molecules involved in its metabolism could be useful to prevent side effects. Polymorphisms of thiopurine methyltransferase enzyme (TPMT) that result in low enzymatic activity have been associated with an increased risk of myelotoxicity, especially in Caucasians; however, in Asians it is assumed that the variants of nudix hydrolase 15 (NUDT15) are more relevant in the development of toxicity. Age is also important, since in elderly patients the risk of complications seems to be increased. Moreover, the primo-infection of Epstein Barr virus and cytomegalovirus under thiopurine treatment has been associated with severe lymphoproliferative disorders. In addition to assessing individual characteristics that may influence thiopurines treatment outcomes, this review also discusses other strategies to optimize the therapy. Low-dose thiopurines combined with allopurinol can be used in hypermethylators and in thiopurine-related hepatotoxicity. The measurement of metabolites could be useful to assess compliance, identify patients at risk of adverse events and also facilitating the management of refractory patients. Thioguanine is also a rescue therapy in patients with toxicity related to conventional thiopurine therapy. Finally, the current indications for thiopurines in monotherapy or in combination with biologics, as well as the optimal duration of treatment, are also reviewed.

Anti-TNF and immunosuppressive combination therapy is preferential to inducing clinical remission in patients with active inflammatory bowel disease: A systemic review and meta-analysis

OBJECTIVE

To compare the efficacy and safety of a combination therapy of biologics and immunosuppressants with biological monotherapy in inflammatory bowel disease (IBD) in a systematic review and meta-analysis.

METHODS

Eligible randomized controlled trials (RCTs) on the comparison of the efficacy and safety of biologics and immunomodulators with biological monotherapy were identified from the EMBASE, PubMed and the Cochrane Library databases published up to 1 May 2020. Raw data were extracted, pooled relative risk (RR) and 95% confidence interval (CI) was calculated, the fixed-effect and inverse variance models were used. Funnel plots were performed to analyze publication bias.

RESULTS

Twelve RCTs were eligible for analysis. Overall, there was statistically a benefit for combination treatment over biologic monotherapy (IFX/ADA) in inducing clinical remission and preventing relapse in patients with IBD (RR 0.89, 95% CI 0.80-0.98). Moreover, the combination therapy was superior to biological monotherapy for active CD (RR 0.83, 95% CI 0.73-0.94). Also, there were significant benefits for combination therapy in the subgroup treated with infliximab (IFX) (RR 0.83, 95% CI 0.70-0.97).

CONCLUSIONS

Combination therapy has slight benefits in inducing clinical remission in active CD compared with biological monotherapy. Patients with IBD who receive therapy with IFX and immunomodulator also have a mild advantage in comparison with those treated with IFX monotherapy.

Withdrawal of Combination Immunotherapy in Paediatric Inflammatory Bowel Disease-An International Survey of Practice

OBJECTIVES

To assess current practices around the use of combination immunosuppression in paediatric inflammatory bowel disease (PIBD) with a focus on the subsequent withdrawal process.

METHODS

A web-based, 43-question survey.

RESULTS

Surveys were completed by 70 paediatric gastroenterologists (PGs) from 27 nations across Europe, North America, Oceania and Asia from 62 centres covering approximately 15,000 PIBD patients (median of 200 patients [interquartile range (IQR) 130-300] per centre). Routine use of co-immunosuppression was significantly higher with infliximab (IFX) versus adalimumab (ADL) ([61/70, 87.1%] compared with [23/70, 32.9%]; P < 0.01). Thiopurines (azathioprine [AZA] or 6-mercaptopurine) were the preferred option overall for co-immunosuppression. They were favoured with either IFX or ADL (76% and 77%, respectively) and in both ulcerative colitis (UC) and Crohn disease (CD) (84% and 69%) compared with methotrexate (MTX).Immunomodulators were the preferred choice as the initial drug to be withdrawn from the combination therapy rather than anti-tumour necrosis factor-alpha (anti-TNFα) therapy (59/67, 88% [P < 0.01]). The most common withdrawal time was after 6-12 months, with this decision usually based on clinical assessment rather than a scheduled withdrawal time (51/67, 76% vs 16/67, 24%). Indicators of mucosal healing and therapeutic drug monitoring results tended to be the most important "clinical factors" in the withdrawal decision (P = 0.05).

CONCLUSION

Most PG's favour initial withdrawal of immunomodulator (usually thiopurines) rather than biologic therapy in the step-down process, usually after 6-12 months based on sustained clinical remission. This survey precedes an in-depth, multicentre study of clinical outcomes of withdrawal of co-immunosuppression in PIBD.

Biologics recommendations in the ECCO guidelines on therapeutics in Crohn's disease: medical treatment

In 2019, the European Crohn's and Colitis Organisation released guidelines for the medical management of Crohn's disease, concerning the induction of remission, the maintenance of remission and the treatment of fistulising perianal disease. This review summarises the key recommendations regarding the use of biologics in these settings.

Current Strategies and Potential Prospects of Nanomedicine-Mediated Therapy in Inflammatory Bowel Disease

Inflammatory bowel diseases (IBD) such as Crohn's disease and ulcerative colitis are highly debilitating. IBDs are associated with the imbalance of inflammatory mediators within the inflamed bowel. Conventional drugs for IBD treatment include anti-inflammatory medications and immune suppressants. However, they suffer from a lack of bioavailability and high dose-induced systemic side effects. Nanoparticle (NP)-derived therapy improves therapeutic efficacy and increases targeting specificity. Recent studies have shown that nanomedicines, based on bowel disease's pathophysiology, are a fast-growing field. NPs can prolong the circulation period and reduce side effects by improving drug encapsulation and targeted delivery. Here, this review summarizes various IBD therapies with a focus on NP-derived applications, whereas their challenges and future perspectives have also been discussed.

AGA Technical Review on the Medical Management of Moderate to Severe Luminal and Perianal Fistulizing Crohn's Disease

The incidence and prevalence of Crohn's disease (CD) is rising globally. Patients with moderate to severe CD are at high risk for needing surgery and hospitalization and for developing disease-related complications, corticosteroid dependence, and serious infections. Optimal management of outpatients with moderate to severe luminal and/or fistulizing (including perianal) CD often requires the use of immunomodulator (thiopurines, methotrexate) and/or biologic therapies, including tumor necrosis factor-α antagonists, vedolizumab, or ustekinumab, either as monotherapy or in combination (with immunomodulators) to mitigate these risks. Decisions about optimal drug therapy in moderate to severe CD are complex, with limited guidance on comparative efficacy and safety of different treatments, leading to considerable practice variability. Since the last iteration of these guidelines published in 2013, significant advances have been made in the field, including the regulatory approval of 2 new biologic agents, vedolizumab and ustekinumab. Therefore, the American Gastroenterological Association prioritized updating clinical guidelines on this topic. To inform the clinical guidelines, this technical review was completed in accordance with the GRADE (Grading of Recommendations Assessment, Development and Evaluation) framework. The review addressed the following focused questions (in adult outpatients with moderate to severe luminal CD): overall and comparative efficacy of different medications for induction and maintenance of remission in patients with or without prior exposure to tumor necrosis factor-α antagonists, comparative efficacy and safety of biologic monotherapy vs combination therapy with immunomodulators, comparative efficacy of a top-down (upfront use of biologics and/or immunomodulator therapy) vs step-up treatment strategy (acceleration to biologic and/or immunomodulator therapy only after failure of mesalamine), and the role of corticosteroids and mesalamine for induction and/or maintenance of remission. Finally, in adult outpatients with moderate to severe fistulizing CD, this review addressed the efficacy of pharmacologic interventions for achieving fistula and the role of adjunctive antibiotics without clear evidence of active infection.

Novel trends with biologics in inflammatory bowel disease: sequential and combined approaches

Inflammatory bowel disease (IBD) management has changed dramatically over the past 20 years, after the introduction of targeted biological therapies. However, the impact of these new drugs in changing the natural history of disease is still under debate. Recent evidence seems to suggest that the extent of their efficacy might be, at least partially, dependent on the timing of their introduction and on the subsequent management strategy. In this complex landscape, the potential role for a more dynamic approach with treatments based on sequencing and combining targeted therapies has been explored only minimally so far. In this review, we aim to explore the potential biological rationale behind the use of sequential and combination therapies in IBD, to summarise the current knowledge on this topic and to propose a management algorithm that combines these notions.

Use of thiopurines in inflammatory bowel disease: an update

Inflammatory bowel disease (IBD), once considered a disease of the Western hemisphere, has emerged as a global disease. As the disease prevalence is on a steady rise, management of IBD has come under the spotlight. 5-Aminosalicylates, corticosteroids, immunosuppressive agents and biologics are the backbone of treatment of IBD. With the advent of biologics and small molecules, the need for surgery and hospitalization has decreased. However, economic viability and acceptability is an important determinant of local prescription patterns. Nearly one-third of the patients in West receive biologics as the first/initial therapy. The scenario is different in developing countries where biologics are used only in a small proportion of patients with IBD. Increased risk of reactivation of tuberculosis and high cost of the therapy are limitations to their use. Thiopurines hence become critical for optimal management of patients with IBD in these regions. However, approximately one-third of patients are intolerant or develop adverse effects with their use. This has led to suboptimal use of thiopurines in clinical practice. This review article discusses the clinical aspects of thiopurine use in patients with IBD with the aim of optimizing their use to full therapeutic potential.

Combination therapy in inflammatory bowel disease - from traditional immunosuppressors towards the new paradigm of dual targeted therapy

BACKGROUND

Combining immunosuppressors has been proposed as a strategy to enhance treatment efficacy in Inflammatory Bowel Disease (IBD).

AIM

To summarize current evidence on combinations of targeted therapies with traditional immunosuppressors or with other targeted therapies.

METHODS

A literature search on PubMed and Medline databases was performed to identify relevant articles.

RESULTS

Current evidence supports that the combination of infliximab and thiopurines is more effective than monotherapy with both agents in inducing remission in Crohn's Disease and Ulcerative colitis. Data on other combinations of other biologics and traditional immunosuppressors is lacking or show conflicting results. Vedolizumab seems a potentially effective maintenance regimen after calcineurin inhibitors-based rescue therapy in acute severe ulcerative colitis, as an alternative to thiopurines. Dual Targeted Therapy, which is the combination of 2 targeted therapies, might be a reasonable choice in patients with concomitant IBD and extraintestinal manifestations, or in patients with medical-refractory IBD who lack valid alternatives. Combinations with thiopurines are associated with an increased risk of infections and lymphoma. Data on other combinations is scarcer, but no specific safety issue has emerged so far.

CONCLUSIONS

Combination therapies seem to be effective in selected patients, with an overall acceptable safety profile.

Thiopurines and their optimization during infliximab induction and maintenance: A retrospective study in Crohn's disease

BACKGROUND AND AIM

Combining therapy with a thiopurine is favored when commencing infliximab in Crohn's disease; however, the optimal 6-thioguanine nucleotide (TGN) level and how long to continue thiopurines after induction are uncertain. We aimed to compare outcomes after induction and during maintenance in combination therapy versus infliximab monotherapy in Crohn's and to examine whether TGN levels were associated with outcomes.

METHODS

Crohn's patients induced with infliximab with or without concomitant thiopurines were retrospectively identified. Response to induction and clinical outcomes in subsequent 6-month maintenance semesters were analyzed. A TGN level ≥235 pmol/8 × 10⁸ red blood cells was considered therapeutic.

RESULTS

In 89 patients, response to induction was higher in combination therapy than monotherapy (74 vs 47%, P = 0.04). This benefit was only seen in patients with a therapeutic TGN (odds ratio 3.72, confidence interval 1.07-13.0, P = 0.04). Combination therapy during induction yielded a three times longer time to subsequent need for treatment escalation or treatment failure compared with monotherapy (29 vs 9 months, P = 0.01), with both therapeutic and subtherapeutic TGNs independent predictors on multivariate analysis. Among 370 semesters, there was no difference in outcomes between combination therapy and monotherapy (P = 0.42), nor when combination semesters were stratified by therapeutic versus subtherapeutic TGN (P = 0.56). In semester 1 only, a significantly higher remission rate was observed with therapeutic compared with subtherapeutic TGN (76% vs 33%, P = 0.02).

CONCLUSIONS

Combination therapy dosed with an optimized thiopurine was superior to infliximab monotherapy for induction of response, durability of response, and clinical outcomes in the first 6 months following induction. Thereafter, combination therapy yielded no clinical advantage, supporting consideration of thiopurine withdrawal on a case-by-case basis.

Is It Useful to Monitor Thiopurine Metabolites in Pediatric Patients with Crohn's Disease on Combination Therapy? A Multicenter Prospective Observational Study

BACKGROUND

The additional value of azathioprine concomitant treatment on infliximab pharmacokinetics in children is not well described yet.

AIMS

In the present study, we aimed to describe the relationship between thiopurine metabolite levels, infliximab trough levels, anti-IFX antibody formation, and clinical and laboratory markers of disease activity in pediatric patients with Crohn's disease, and to assess non-adherence.

METHODS

Data were collected prospectively during repeated visits from pediatric patients followed for Crohn's disease in two Czech pediatric inflammatory bowel disease centers between January 2016 and June 2017. Thiopurine metabolites (6-thioguanine and 6-methylmercaptopurine) were measured by high-performance liquid chromatography. Infliximab trough levels and anti-IFX antibody serum levels were measured routinely by ELISA. The risk of loss of response to infliximab therapy was also assessed.

RESULTS

A significant association between infliximab serum levels and 6-thioguanine erythrocyte levels was observed when tested as categorical variables (63 patients, 321 observations). To predict infliximab levels > 5 µg/mL, we propose a 6-thioguanine cutoff of 278 pmol/8 × 10⁸ erythrocytes (sensitivity, 0.799; specificity, 0.347). A higher loss-of-response-to-infliximab rate (tested in a subgroup of 51 patients) was observed in patients with undetectable 6-thioguanine levels than in those with detectable levels (p = 0.026). Non-adherence to azathioprine therapy was suspected in 20% of patients.

CONCLUSION

Thiopurine metabolite monitoring in pediatric patients with Crohn's disease is useful when optimizing combination therapy. Pediatric patients with undetectable 6-thioguanine levels are more likely to lose response to infliximab therapy. When targeting optimal infliximab levels, the 6-thioguanine cutoff levels in children appear to be higher than in adults.

Therapeutic Drug Monitoring for Current and Investigational Inflammatory Bowel Disease Treatments

This article reviews therapeutic drug monitoring (TDM) use for current inflammatory bowel disease (IBD) treatments. IBD comprises Crohn's disease and ulcerative colitis-chronic gastrointestinal inflammatory disorders. Treatment options for moderate to severe IBD include thiopurines; methotrexate; biologic agents targeting tumor necrosis factor, α4β7 integrin or interleukins 12 and 23; and Janus kinase inhibitors. TDM is recommended to guide treatment decisions for some of these agents. Published literature concerning TDM for IBD treatments was reviewed. S.D.L., R.S., and E.V.L. drew on their clinical experiences. Polymorphisms resulting in altered enzymatic activity inactivating thiopurine metabolites can lead to myelotoxicity and hepatotoxicity. Increased elimination of biologic agents can result from immunogenicity or higher disease activity, leading to low drug concentration and consequent nonresponse or loss of response. TDM may aid treatment and dose decisions for individual patients, based on monitoring metabolite levels for thiopurines, or serum drug trough concentration and antidrug antibody levels for biologic agents. Challenges remain around TDM implementation in IBD, including the lack of uniform assay methods and guidance for interpreting results. The Janus kinase inhibitor tofacitinib is not impacted by enzyme polymorphisms or disease activity, and is not expected to stimulate the formation of neutralizing antidrug antibodies. TDM is associated with implementation challenges, despite the recommendation of its use for guiding many IBD treatments. Newer small molecules with less susceptibility to patient variability factors may fulfill the unmet need of treatment options that do not require TDM, although further study is required to confirm this.

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.

Optimising management strategies of inflammatory bowel disease in resource-limited settings in Asia

Over the 21st century, inflammatory bowel disease (IBD) has become a global disease with increasing prevalence reported in the Asian subcontinent as a result of rapid urbanisation, industrialisation, and westernisation of lifestyles. Although rates of surgery have shown a temporal decrease globally because of the increasing availability of new drugs and early initiation of effective therapy, health-care costs associated with IBD have continued to rise. The increase in IBD prevalence in resource-limited countries poses a substantial health-care burden. Drugs are not universally accessible or available. An optimised and practical management strategy of IBD in resource-limited countries in Asia is urgently needed. Special consideration should be made to balance the risk of undertreatment (and suboptimal disease control) because of financial constraints with the risk of overtreatment, which is associated with side-effects and costly therapeutics. In this Series paper, we summarise the current approach in optimising conventional therapies, use of other therapies, and de-escalation of biologics in low-resource settings in Asia. The long-term objective is to strive for more effective and affordable therapies with sustained durability of benefit.

Discontinuation of Immunosuppressive Medications in Children With Inflammatory Bowel Disease on Combination Therapy

We determined the frequency and factors associated with the first clinical relapse after immunomodulator (IM) withdrawal in a cohort of children with inflammatory bowel disease on combination therapy. A total of 105 patients (89 with Crohn disease [CD]) in clinical remission were included (91 [86.7%] were on infliximab, 53 [50.5%] with methotrexate, and 52 on azathioprine). The median duration of combination therapy was 2.1 years (interquartile range [IQR] 1.3-2.8). Only 11 (10.5%) patients experienced a clinical relapse over a median duration of follow-up of 12.0 months (IQR 5.0-19.0) after IM discontinuation. The median baseline pediatric CD activity index in those with CD who relapsed after IM discontinuation was 47.5 (IQR: 35.0-55.0) versus those who did not relapse (median 35.0, IQR: 20.0-52.5; P = 0.04). In the patients who did not relapse, the median IFX trough level at IM discontinuation was 6.2 and 3.8 μg/mL in those who relapsed.

First United Arab Emirates consensus on diagnosis and management of inflammatory bowel diseases: A 2020 Delphi consensus

Ulcerative colitis and Crohn’s disease are the main entities of inflammatory bowel disease characterized by chronic remittent inflammation of the gastrointestinal tract. The incidence and prevalence are on the rise worldwide, and the heterogeneity between patients and within individuals over time is striking. The progressive advance in our understanding of the etiopathogenesis coupled with an unprecedented increase in therapeutic options have changed the management towards evidence-based interventions by clinicians with patients. This guideline was stimulated and supported by the Emirates Gastroenterology and Hepatology Society following a systematic review and a Delphi consensus process that provided evidence- and expert opinion-based recommendations. Comprehensive up-to-date guidance is provided regarding diagnosis, evaluation of disease severity, appropriate and timely use of different investigations, choice of appropriate therapy for induction and remission phase according to disease severity, and management of main complications.

De-escalation of medical therapy in inflammatory bowel disease

Treatment strategies for inflammatory bowel disease (IBD) now increasingly target deep remission, yet the resultant more aggressive use of medical therapy is associated with potentially serious adverse events and significant costs. It is, therefore, of vital importance to consider when, how and in whom medical therapy may be safely de-escalated. This issue is of great potential relevance in the current SARS-Cov-2 pandemic. In this review, we first discuss the rationale for drug withdrawal in IBD, before considering the available data on withdrawal of 5-aminosalicylates (5-ASA), immunomodulators (IM) and biological therapy in both ulcerative colitis (UC) and Crohn's Disease (CD). We consider how to identify patients most appropriate for drug withdrawal and outline a potential monitoring strategy for the early detection of relapse following drug withdrawal. We conclude with important future perspectives in this challenging field, and highlight ongoing trials that are likely to shape practice in the years to come.