The benefit of therapeutic drug monitoring (TDM) and implementation of recommendations from the Selection of Therapeutic Targets in Inflammatory Bowel Disease (IBD, STRIDE) are discussed in the IBD community. We report real-world data in ulcerative colitis patients receiving first-line tumour necrosis factor inhibitor (TNFi) treatment followed by TDM, and assess how implementation of the STRIDE II recommendations might affect clinical practice.

Adult, biologically naïve UC patients starting TNFi between 2014 and 2021 at Oslo University Hospital were included in a medical chart review study, and data were collected at three and twelve months after the start of treatment. Target serum drug levels were defined as ≥7.5 mg/L for adalimumab and ≥5 mg/L for infliximab.

Of 141 included patients, 36% were in clinical and biochemical (combined) remission after twelve months. Among 102 treatment persistent patients, 54% were in combined remission after twelve months. Target drug level at three months was associated with clinical remission at twelve months (OR = 2.97, 95% CI [1.24-7.12]) and biochemical remission at twelve months (OR = 2.64, 95% CI [1.03-6.77]). In total, 56% of recorded dosage adjustments were related only to serum drug levels.

Combined remission rates at twelve months for treatment persistent patients suggest that 46% should have been considered for a change of treatment according to the STRIDE II recommendations. A majority of dosage adjustments were made proactively. Target drug level at three months was associated with remission at twelve months and supports the use of proactive TDM.

Interleukin-23 (IL-23), a member of the IL-12 family of cytokines, plays a critical role in intestinal homeostasis and inflammation and is strongly implicated in the pathogenesis of inflammatory bowel disease (IBD). Therapies targeting the p19 subunit of IL-23 have recently expanded the therapeutic options for IBD demonstrating efficacy and safety for the treatment of moderate to severe Crohn's disease (CD). Thus, in this review, we provide an overview of agents targeting the IL-23 pathway in CD, highlighting similarities and differences of specific IL-23 inhibitors. Furthermore, we summarize key phase 3 trials and head-to-head trials, focusing on design features and interpretation. Finally, we discuss the positioning of selective IL-23 agents for CD treatment along with areas of unmet clinical needs. However, real-world data will offer additional comparative effectiveness information, data for disease subtypes, and insights into the long-term outcomes of IL-23 inhibition. Looking ahead, ongoing phase 3 studies testing p19-specific selective IL-23 inhibitors are expected to expand the therapeutic options for patients with complex phenotypes, including those with extraintestinal manifestations (EIMs), fistulas, and strictures. Advances in molecular and cellular characterization, including the development of predictive molecular biomarkers, may help guide clinical decision-making, enabling more personalized treatment approaches. Precision medicine studies may further enhance our understanding of the molecular biology of IL-23, shedding light on how these agents work in complex CD and clarify their potential complementary or synergistic effects with other therapies.

Infliximab treatment failure in patients with inflammatory bowel disease may result from sub-optimal infliximab trough level. An understanding of pharmacokinetics (PKs) is important to maintain an optimal trough level. PK studies of the switch to subcutaneous (SC) infliximab from intravenous (IV) infliximab using real-world data are lacking. We aimed to develop a population PK model of IV and SC infliximab to predict individual infliximab exposure during maintenance therapy.

We used data from prospectively collected data on IV and SC infliximab concentrations in patients with inflammatory bowel disease receiving maintenance treatment from February 2020 to December 2022 at Samsung Medical Center. Population PK analysis was conducted by using a two-compartment model with first-order absorption and first-order elimination. Goodness-of-fit plots and visual predictive check were used to evaluate the PK model.

A total of 2,132 samples from 181 patients (149 Crohn's disease and 32 ulcerative colitis) were analyzed. We developed an infliximab population PK model using body mass index, albumin, C-reactive protein level, and the anti-drug antibody level and validated its predictive performance.

It may be possible to predict the infliximab trough level of both IV and SC infliximab in patients with inflammatory bowel disease during maintenance treatment by using our model in real-world practice.

Intravenous (IV) infliximab (IFX) combined with an immunomodulator (combination therapy) outperforms IV IFX monotherapy in terms of clinical, endoscopic, and immunogenicity outcomes in patients with inflammatory bowel disease (IBD). With the advent of subcutaneous (SC) IFX, which is associated with higher serum drug concentrations, it is essential to assess whether SC IFX monotherapy provides similar pharmacokinetic and clinical benefits as combination therapy.

We conducted a systematic review and meta-analysis (until August 2024), of studies on patients with IBD treated with SC IFX. The primary outcome was anti-drug antibodies (ADAs) formation within 12 months (M) after starting SC IFX or after switching from IV to SC IFX. Secondary outcomes included treatment persistence, clinical efficacy, and biochemical parameters.

Twenty-four studies (n = 3172) were included. Among patients transitioning from IV IFX induction to SC IFX, immunogenicity was more prevalent with monotherapy than combination treatment (median, 68% vs 48%; odds ratio [OR], 3.29; 95% confidence interval [CI], 1.71-6.31; P < .001). Clinical response rates at 12M were comparable, with a trend favoring combination therapy (OR, 0.73; 95% CI, 0.50-1.06; P = .10). In patients switching from IV maintenance to SC IFX, relapse rates were low (median, 12% at 6M, 11% at week 50), with stable biochemical markers. Treatment persistence was high (93% at 6M, 92% at 12M). Among patients with quiescent disease at the time of switching, 1-year relapse rates were 9% to 11%, with baseline immunogenicity predicting treatment failure.

SC IFX monotherapy is associated with higher immunogenicity rates compared with combination therapy, particularly in new IFX starters. Although clinical response was comparable, a trend favoring combination therapy warrants further investigation.

Existing findings on outcomes of anti-tumor-necrosis-factor (TNF) therapy in patients with inflammatory bowel diseases (IBD) are largely based on retrospective studies. We aimed to investigate real-world outcomes of anti-TNF therapy and predictors thereof in a prospective IBD cohort.

In a Danish multicenter cohort of adult bio-naïve patients with IBD treated with anti-TNF, we assessed clinical response and remission to induction therapy using clinical disease activity scoring indices at Week 14. In patients who continued treatment beyond the induction period, we also assessed loss of response (LOR), drug withdrawal, and major IBD surgery during maintenance therapy.

This study included 774 patients (706 infliximab, 68 adalimumab) followed for a median duration of 125 weeks Clinical response was achieved in 209/331 (67.4%) of ulcerative colitis (UC) and 125/197 (74.0%) of Crohn's disease (CD) patients, while 143/331 (46.1%) UC and 81/197 (47.9%) CD patients achieved clinical remission. In 294 UC and 309 CD patients received maintenance therapy, while 86/294 (29.3%) UC and 78/309 (25.2%) CD patients experienced LOR. Active smoking and less severe disease activity predicted favorable outcomes in UC, while short disease duration, colonic disease, nonstricturing behavior, and concomitant immunomodulator therapy predicted favorable outcomes in CD.

Clinical response was achieved in 2 in 3 UC and 3 in 4 CD patients, meanwhile, one-third of UC and one-fourth of CD patients experienced LOR despite the short disease duration in this study. Several clinical features were associated with outcomes and may be useful predictors of anti-TNF treatment response.

Point-of-care tests (POCT) enable immediate measurement of anti-TNF blood concentrations. This study examined the association between loss of response (LOR) to infliximab (IFX) or adalimumab (ADL) and serum concentrations measured with POCT and enzyme-linked immunosorbent assay (ELISA) in inflammatory bowel disease (IBD) patients.

Patients with IBD with stored IFX or ADL serum samples were recruited. POCT was conducted, agreement with ELISA was evaluated using Bland-Altman plots. The primary endpoint was LOR defined as change in therapy, IBD-related surgery, new actively draining fistula, and/or endoscopic deterioration. ROC curves and quartile analysis assessed the association between concentrations and LOR.

A total of 176 patients were included (92 IFX/84 ADL, 154 Crohn's disease, and 22 ulcerative colitis). Median follow-up time was 20 months (interquartile range 9-38). LOR occurred in 37/84 (44%) ADL users and 55/92 (60%) IFX users. Median serum concentrations were significantly lower in LOR patients compared with sustained response, measured by both techniques for ADL (POCT: 6.45 vs 13.48 µg/mL, P <.001; ELISA: 4.80 vs 8.80 µg/mL, P <.001) and IFX (POCT: 2.39 vs 6.50 µg/mL, P <.001; ELISA: 1.70 vs 4.40 µg/mL, P <.001). Quartile analysis revealed that higher serum concentrations were associated with maintained response. ROC curve analysis demonstrated good or excellent discrimination for POCT and ELISA in association with LOR (AUC IFX: POCT = 0.82, ELISA = 0.76; AUC ADL: POCT = 0.82, ELISA = 0.81; all P <.0001). An overestimation of serum concentrations with POCT was observed.

Serum ADL and IFX POCT concentrations are comparable to ELISA and associated with LOR, indicating its clinical utility.

Several therapeutic advances have been achieved over the past two decades for inflammatory bowel disease (IBD). The expanding therapeutic armamentarium and the increasingly ambitious treatment targets have led to an increased use of advanced therapies and better outcomes. Nevertheless, many patients remain suboptimally treated and are at risk of disease progression, hospital admission, and surgery, even when advanced therapies are cycled, escalated, or combined. Conversely, IBD can also be characterised by an indolent disease course. Top-down and treat-to-target strategies, although beneficial in a substantial proportion of patients, might not be advantageous in patients with mild disease and might risk overtreatment. Identifying patients with mild activity and a benign disease trajectory in the long-term is important; unnecessary exposure to advanced therapies increases the risk of adverse events and increases financial costs and health-care resource utilisation. This Review details the importance of adopting clinical strategies to avoid the pitfalls of undertreating and overtreating IBD.

Therapeutic drug monitoring is recommended to optimize infliximab use and improve outcome in chronic inflammatory disorders.

To describe a simple and affordable liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to measure infliximab in serum.

Infliximab was measured using winged stable isotope-labeled peptides as internal standards. Linearity, lower limit of measuring interval, limit of detection, precision, accuracy, carryover, and ion suppression were evaluated. Method comparison against 2 enzyme-linked immunosorbent assay (ELISA) methods (Remsima Monitor and IDKmonitor Infliximab) and anti-drug antibody (ADA) interference were evaluated using clinical specimens from inflammatory bowel disease patients (N = 237).

Analytical run time and sample preparation time were 5 minutes per sample and 3 hours per batch, respectively. Analytical measurement interval and limit of detection were 0.50 to 50.0 μg/mL (R2 = 0.998) and 0.25 μg/mL, respectively. The intraday and interday imprecision percentage coefficients of variation were less than 6.1%. Accuracy was 94.2% to 98.7%. No significant ion suppression or carryover was observed. Infliximab concentrations measured by LC-MS/MS showed good agreement with those measured by Remsima Monitor (mean percentage difference, 5.7%; 95% CI, -1.2% to 12.6%) but were markedly lower than those measured by IDKmonitor (-32.6%; -35.8% to -29.4%), demonstrating significant bias between ELISAs. Although a good agreement between LC-MS/MS and ELISA was observed for ADA-negative samples (-3.5%; -12.8% to 5.9%), a significant bias was observed for ADA-positive samples (13.6%; 1.7% to 25.6%).

This simple, fast, and affordable LC-MS/MS method for infliximab quantitation could improve standardization of infliximab quantitation and optimization of infliximab use in patients with high-titer ADA.

Superior efficacy of subcutaneous infliximab (CT-P13 SC) over placebo for maintenance therapy in patients with Crohn's disease (CD) and ulcerative colitis (UC) was demonstrated in the randomized LIBERTY-CD and LIBERTY-UC studies. The current post hoc analysis compared outcomes with CT-P13 SC by baseline immunosuppressant use.

Patients with moderately to severely active CD or UC randomized to the CT-P13 SC maintenance arm of the 54-week LIBERTY trials at week 10 and who were treated in the open-label extension (weeks 56-102) were included. Pharmacokinetic, efficacy, biomarker, safety, and immunogenicity endpoints were evaluated by baseline immunosuppressant use (monotherapy vs combination therapy).

A total of 192 patients with CD (monotherapy, n = 126; combination therapy, n = 66) and 237 patients with UC (monotherapy, n = 180; combination therapy, n = 57) were included. In both studies, efficacy outcomes were generally comparable between monotherapy and combination therapy at week 54 or week 102. Serum concentrations were generally higher, and antidrug antibody-positive conversion rates were lower, with combination therapy relative to monotherapy. In combined analyses of CD and UC, comparable safety profiles were observed between monotherapy and combination therapy.

Despite some differences in pharmacokinetics and immunogenicity between CT-P13 SC received alone or in combination with immunosuppressants in patients with CD or UC, efficacy outcomes at week 54 or week 102 were generally comparable. The overall safety profile and incidence of systemic injection reactions were also comparable between monotherapy and combination therapy.

Autoimmune and inflammatory diseases are rising globally yet widely effective therapies remain elusive. Most treatments have limited efficacy, significant potential side effects, or eventually lose response, underscoring the urgent need for new therapeutic approaches. We recently discovered that ETS2, a transcription factor, functions as a master regulator of macrophage-driven inflammation-and is causally linked to the pathogenesis of multiple inflammatory diseases via human genetics. The pleotropic inflammatory effects of ETS2 included upregulation of many cytokines that are individually targeted by current disease therapies, including TNFα, IL-23, IL1β, and TNF-like ligand 1A signaling. With the move toward combination treatment-to maximize efficacy-targeting ETS2 presents a unique opportunity to potentially induce a broad therapeutic effect. However, there will be multiple challenges to overcome since direct ETS2 inhibition is unlikely to be feasible. Here, we discuss these challenges and other unanswered questions about the central role that ETS2 plays in macrophage inflammation.

Carriage of the HLA-DQA1*05 allele is associated with development of antidrug antibodies (ADAs) to antitumor necrosis factor (anti-TNF) therapy in patients with Crohn's disease. However, ADA is not uniformly associated with treatment failure. We aimed to determine the impact of carriage of HLA-DQA1*05 allele on outcome of biologic therapy evaluated by drug persistence.

A multicenter, retrospective study of 877 patients with inflammatory bowel disease (IBD) treated with anti-TNF therapy with HLA-DQA1*05 genotypes were generated by imputation from whole genome sequence using the HIBAG package, in R. Primary end point was anti-TNF therapy persistence, (time to therapy failure), segregated by HLA-DQA1*05 allele genotype and development of a risk score to predict anti-TNF therapy failure, incorporating HLA-DQA1*05 allele genotype status (LORisk score).

In all, 877 patients receiving anti-TNF therapy were included in our study; 543 (62%) had no copy, 281 (32%) one copy, and 53 (6%) 2 copies of HLA-DQA1*05 allele. Mean time to anti-TNF therapy failure in patients with 2 copies of HLA-DQA1*05 allele was significantly shorter compared with patients with 0 or 1 copy at 700 days' follow-up: 418 vs 541 vs 513 days, respectively (P = .012). Factors independently associated with time to anti-TNF therapy failure included carriage of HLA-DQA1*05 allele (hazard ratio [HR], 1.2, P = .02; female gender HR, 1.6, P < .001; UC phenotype HR, 1.4, P = .009; and anti-TNF therapy type [infliximab], HR, 1.5, P = .002). The LORisk score was significantly associated with shorter time to anti-TNF therapy failure (P < .001).

Carriage of 2 HLA-DQA1*05 alleles is associated with less favorable outcomes for patients receiving anti-TNF therapy with shorter time to therapy failure. HLA-DQA1*05 genotype status in conjunction with clinical factors may aid in therapy selection in patients with IBD.

Inflammatory bowel disease (IBD) represents a significant disease burden marked by chronic inflammation and complications that adversely affect patients' quality of life. Effective diagnostic strategies involve clinical assessments, endoscopic evaluations, imaging studies, and biomarker testing, where early diagnosis is essential for effective management and prevention of long-term complications, highlighting the need for continual advancements in diagnostic methods. The intricate interplay between genetic factors and the outcomes of biological therapy is of critical importance. Unraveling the genetic determinants that influence responses and failures to biological therapy holds significant promise for optimizing treatment strategies for patients with IBD on biologics. Through an in-depth examination of current literature, this review article synthesizes critical genetic markers associated with therapeutic efficacy and resistance in IBD. Understanding these genetic actors paves the way for personalized approaches, informing clinicians on predicting, tailoring, and enhancing the effectiveness of biological therapies for improved outcomes in patients with IBD.

Therapeutic drug monitoring of adalimumab (ADA) is still controversial.

To study the association between ADA trough levels in the early stages of treatment with biological remission (BR) and drug survival in Crohn's disease (CD).

Retrospective cohort study.

Patients treated with ADA with available trough levels at weeks 2 and 6 (after the first induction and maintenance dose, respectively) were included. Fecal calprotectin (Fcal) and C-reactive protein (CRP) were registered at baseline, week 24, and week 52. BR was defined as Fcal <200 µg/g and CRP <5 mg/dl. Treatment survival and the need for dose escalation were assessed at week 52. Receiver operating characteristic (ROC) curves were constructed to assess the diagnostic accuracy of ADA cutoff levels for BR. Quartile-specific comparisons were performed to evaluate differences in the proportion of patients achieving BR at weeks 24 and 52, drug survival, and dose escalation.

In all, 112 patients were included. ADA trough levels at week 6 were higher in patients achieving BR at week 24 (12.32 μg/ml vs 10.3 μg/ml, p = 0.0008), week 52 (12.3 μg/ml vs 10.8 μg/ml, p = 0.035), and in patients with 1-year treatment persistence (12.17 μg/ml vs 9.7 μg/ml, p = 0.03), but lower in patients requiring maintenance intensification (9.7 μg/ml vs 12.2 µg/ml, p < 0.0001). ADA week 6 trough levels >12.27 μg/ml predicted BR at week 24 with 79.7% specificity and 79.5% positive predictive value. Patients in the third quartile (Q3) and fourth quartile (Q4) of ADA levels at week 6 exhibited higher rates of BR at week 24, BR at week 52, 1-year drug survival, and less need for dose escalation (all p-values <0.05). In logistic regression, Q3 and Q4 of week 6 levels were significantly associated with BR at week 24 (p = 0.02 and p = 0.001); and week 6 Q4 with BR at week 52 (p = 0.02), treatment persistence (p = 0.03), and lower dose escalation (p = 0.004). ADA trough levels at week 2 did not show similar associations.

ADA trough levels at week 6 are associated with BR at weeks 24 and 52, drug survival, and need for dose escalation in CD. However, ADA concentrations at week 2 failed to yield similar results.

Therapeutic drug monitoring (TDM) for dose modification of biologics has the potential to improve patient outcomes. The US Food and Drug Administration (FDA) and the American Association of Pharmaceutical Scientists (AAPS) hosted the first US-based public workshop on TDM of biologics with contributions from a broad array of interested parties including healthcare providers, clinical pharmacologists, test developers, bioanalysis and immunogenicity scientists, health economics and outcomes research (HEOR) experts and regulators. The key insight was that despite a body of evidence to support TDM in certain therapeutic areas, there remain substantial challenges to widespread clinical implementation. There is a lack of consensus regarding the integration of TDM in clinical guidelines, and a lack of consensus on the cost-effectiveness of TDM; both factors contribute to the difficulty that healthcare providers face in obtaining reimbursement for TDM (both coverage of testing itself, and coverage of potential dosing modifications). The HEOR experts outlined alternative routes to obtaining reimbursement and suggested advocating for changes in coverage policies to promote TDM use in the clinic. Reaching alignment across policy makers, patients and advocacy groups, payers, and healthcare providers, on specific treatment settings where TDM will be clearly beneficial, was identified as an important step to advancing TDM implementation for the benefit of patients.

Pediatric inflammatory bowel disease (PIBD) is a chronic inflammatory disorder of the gastrointestinal tract, with rising global incidence and prevalence. Over the past two decades, biologics have added to the therapeutic armamentarium and revolutionized the approach to treatment of inflammatory bowel disease. The available biologics include monoclonal antibodies which target inflammatory cytokines (anti-tumor necrosis factor alpha, anti-interleukin 12/23) or recruitment of leucocytes to the gastrointestinal tract (anti-alpha4beta7 integrin) and small molecules (Janus kinase inhibitors, sphingosine 1-phosphate-inhibitors) which modify the proinflammatory signaling. Considering their potential disease-modifying ability, recent pediatric guidelines from the West have advocated upfront use of biologics in appropriate clinical scenarios as a top-down approach rather than the conventional step-up approach. Although real-world studies are available regarding the clinical efficacy of biologics in PIBD, there is paucity of long-term outcome and safety data in children. Also, little information is available about the best approach in the newly industrialized - developing countries where PIBD is rising but at the same time, infections are prevalent and resources are limited. In this review, we summarize the efficacy and safety profile of biologics and small molecule drugs and discuss the challenges in the management of PIBD, especially in the developing world, and future directions.

Several therapies have been approved to treat Crohn's disease (CD) and ulcerative colitis (UC), indicating that both diseases may share the same molecular subtypes. The aim of this study is to identify shared patient subtypes with common molecular drivers of disease.

Five public datasets with 406 CD and 421 UC samples were integrated to identify molecular subtypes. Then, the patient labels from 6 independent datasets and 8 treatment datasets were predicted for validating subtypes and identifying the relationship with response status of corticosteroids, infliximab, vedolizumab, and ustekinumab.

Two molecular subtypes were identified from the training datasets, in which CD and UC patients were relatively evenly represented in each subtype. We found 6 S1-specific gene modules related to innate/adaptive immune responses and tissue remodeling and 9 S1-specific cell types (cycling T cells, Tregs, CD8+ lamina propria, follicular B cells, cycling B cells, plasma cells, inflammatory monocytes, inflammatory fibroblasts, and postcapillary venules). Subtype S2 was associated with 3 modules related to metabolism functions and 4 cell types (immature enterocytes, transit amplifying cells, immature goblet cells, and WNT5B+ cells). The subtypes can be replicated in 6 independent datasets based on a 20-gene classifier. Furthermore, response rates to 4 treatments in subtype S2 were significantly higher than those in subtype S1.

This study discovered and validated a robust transcriptome-based molecular classification shared by CD and UC and built a 20-gene classifier. Because 2 subtypes have different molecular mechanisms and drug response, our classification may aid interpretation of heterogeneous molecular and clinical information in inflammatory bowel disease patients.

Inflammatory bowel diseases (IBDs) comprise a group of chronic gastrointestinal disorders characterized by periods of relapse and remission. The mainstay of treatment is medical, involving medications such as steroids, immune modulators, monoclonal antibodies (categorized as biologics), and small molecules. These medications can provide profound therapeutic benefits, but they can also cause severe and irreversible toxicities. Clinicians may utilize laboratory tests in the diagnosis and management of IBD including assessment of disease activity, monitoring medication response or toxicity, surveillance of infectious complications, and detection of nutritional deficiencies. Routine use of laboratory tests may help clinicians avoid reactivation of life-threatening infections such as tuberculosis or hepatitis B virus upon initiation of immune suppressive therapy. They can also be used to detect vitamin deficiencies such as B12 deficiency, which has the potential to cause irreversible neurologic damage. While some laboratory tests constitute established practices, the utility of newer tests such therapeutic drug monitoring (TDM) in the era of biologics is an evolving topic. Although clinical assessment with imaging, endoscopic, and histopathological examination is standard practice, laboratory tests serve as valuable adjuncts. We aim to explore the broad range of laboratory tests available to clinicians and to summarize their application in the current management of IBD in daily clinical practice, with special attention to updates in therapeutic drug monitoring.

Background/Objectives: Dose escalation has been commonly used to achieve and maintain response. We aimed to compare the outcomes of adalimumab or infliximab dose escalation in inflammatory bowel disease (IBD) patients. Methods: Treatment persistence (TP) and predictive factors for remission-free treatment discontinuation (r-fTD) were evaluated in patients treated with adalimumab or infliximab dose escalation between 2019 and 2024. Results: Dose escalation was identified in 142 patients treated with adalimumab (UC: 23.9%; CD: 76.1%) and in 126 patients treated with infliximab (UC: 23.8%; CD: 76.2%). The TP rate was significantly lower in the adalimumab group (35.2%) than the infliximab group (53.2%) (p = 0.003). The survival analysis showed that drug persistence was lower in the adalimumab group compared with the infliximab group (mean time: 74.3 vs. 99.5 months, p < 0.001). TP rates showed no significant differences between UC and CD for both adalimumab (mean time UC: 64.7 months vs. CD: 76.2 months, p = 0.403) and infliximab (mean time UC: 80.3 months and CD: 102.6 months, p = 0.151). The r-fTD rates were significantly higher in the adalimumab group (62.7%) than the infliximab group (39.7%) (p < 0.001). Primary lack of response and secondary loss of response (sLOR) rates were both higher in the adalimumab group (7.7% and 51.4%) than the infliximab group (1.6% and 28.6%). However, serious adverse events were lower in the adalimumab group (2.1%) than the infliximab group (7.9%) (p = 0.027). Conclusions: Infliximab dose escalation was more effective than adalimumab in both UC and CD patients. Regarding the side effect profile, adalimumab dose escalation was found to be safer compared with infliximab.

Background/Objectives: Tumor necrosis factor antagonists (anti-TNFs) have been shown to be an effective treatment for inflammatory bowel disease (IBD). Several factors are associated with anti-TNF treatment failure. This study aims to explore the impact of age on serum concentrations of anti-TNF drugs and antidrug antibodies (ADAbs). Methods: We retrospectively reviewed patients' charts from July 2018 until September 2024 across seven medical centers. Patients with an established diagnosis of IBD receiving infliximab or adalimumab were included. The primary outcome of this study was the effect of age on the anti-TNFs serum drug concentration and ADAb levels. Linear regression was performed to explore the relationship between age and serum anti-TNF drug and ADAb levels. Results: 1093 patients were included in our cohort. In patients receiving infliximab, there was a significant association between older age and increasing ADAbs levels (p = 0.036), whereas in patients treated with adalimumab, there was no significant relationship between older age and ADAb levels (p = 0.771). There was no significant relationship between age and adalimumab serum concentration (p = 0.54). When stratified by age, patients taking infliximab who were >30 years of age developed more ADAbs compared to those aged ≤30 (p = 0.003). Conclusions: Patients older than 30 years of age receiving infliximab monotherapy have higher ADAbs and lower serum drug concentrations than younger patients. There was no statistically significant difference in ADAbs and serum drug concentrations among patients receiving infliximab combination therapy or adalimumab monotherapy.

Inflammatory bowel disease (IBD), encompassing ulcerative colitis and Crohn's disease, is a group of chronic, immune-mediated disorders of the gastrointestinal tract that present substantial clinical challenges owing to their complex pathophysiology and tendency to relapse. A treat-to-target approach is recommended, involving iterative treatment adjustments to achieve clinical response, reduce inflammatory markers and achieve long-term goals such as mucosal healing. Lifelong medication is often necessary to manage the disease, maintain remission and prevent complications. The therapeutic landscape for IBD has evolved substantially; however, a ceiling on therapeutic efficacy remains and surgery is sometimes required (owing to uncontrolled disease activity or complications). Effective IBD management involves comprehensive care, including medication adherence and a collaborative clinician-patient relationship. This Review discusses current therapeutic options for IBD, detailing mechanisms of action, efficacy, safety profiles and guidelines for use of each drug class. We also explore emerging therapies and the role of surgery. Additionally, the importance of a multidisciplinary team and personalized care in managing IBD is emphasized, advocating for patient empowerment and involvement in treatment decisions. By synthesizing current knowledge and emerging trends, this Review aims to equip healthcare professionals with a thorough understanding of therapeutic options for IBD, enhancing informed, evidence-based decisions in clinical practice.

Adalimumab taken every other week is an effective treatment in patients with chronic refractory uveitis. Patients who have a suboptimal response to this treatment may suffer from recurrent inflammation and vision loss. Here, we investigated the use of therapeutic drug monitoring and neutralizing anti-drug antibody detection as a strategy to optimize tumor necrosis factor (TNF)-alpha inhibitor treatment in patients who have a suboptimal response to the initial dosing of adalimumab.

Retrospective cohort study performed in two tertiary referral uveitis services in the United States between 2015 to 2023. Patients with non-infectious uveitis who had a suboptimal response to every two-week dosing of adalimumab and underwent serum adalimumab level with reflex to anti-drug antibody testing were followed. Patients were considered to have neutralizing drug antibodies when serum drug levels were low (less than or equal to 6 mcg/mL) and anti-adalimumab antibodies were present on reflex testing. Treatment adjustment was made by clinicians with the knowledge of serum adalimumab level and the presence or absence of neutralizing drug antibodies. Every two-week dosing of adalimumab was either escalated to weekly dosing or switched to infliximab, an alternate TNF-alpha inhibitor, based on these findings. The primary outcome was success or failure at 12 months, as determined by disease inactivity on steroid-sparing therapy.

32 patients with suboptimal response to the initial dosing of adalimumab were included. 31.2% (n=10) of patients were found to have neutralizing drug antibodies. All patients with neutralizing drug antibodies underwent a medication switch to infliximab with a remission rate of 40% at 12 months. Patients without neutralizing drug antibodies (n=22) underwent dose escalation (77.3%; n=17) or medication switch (22.7%; n=5) and achieved a remission rate of 68.2% at 12 months. Altogether, treatment adjustment based on therapeutic drug monitoring and neutralizing drug antibody detection, in our cohort, resulted in a remission rate of 62.5%.

For patients with uveitis experiencing suboptimal therapeutic response to adalimumab dosed every two weeks, therapeutic drug monitoring and neutralizing drug antibody detection may help clinicians optimize TNF-alpha inhibitor treatment.

Anti-tumor necrosis factor (anti-TNF) therapies are commonly prescribed treatments for Crohn's disease (CD) and ulcerative colitis (UC). Many patients treated with anti-TNF therapy eventually develop anti-drug antibodies (ADAs). Understanding the factors associated with immunogenicity in anti-TNF-treated patients can help guide treatment. The Humira SERENE studies were Phase 3 trials investigating adalimumab induction regimens in CD and UC patients.

We imputed alleles for 7 HLA genes in 1100 patients from the SERENE CD and SERENE UC trials. We then tested these alleles for association with time to immunogenicity. Subsequently, we tested loci significantly associated with immunogenicity for their association with patients who had consistently low drug serum concentrations.

This study replicated the association of HLA-DQA1*05 with time to immunogenicity (hazard ratio [HR] 1.42, p = 2.22E-06). Specifically, HLA-DQA1*05:05 was strongly associated (HR 1.76, p = 2.02E-10) and we detected a novel association represented by HLA-DRB1*01:02 (HR 3.16, p = 2.92E-07). Carriage of HLA-DQA1*05:05 and HLA-DRB1*01:02 was associated with patients who experienced consistently low adalimumab trough concentrations (HLA-DQA1*05:05: odds ratio [OR] 1.98, p = 0.0049; HLA DRB1*01:02: OR 7.06, p = 7.44E-05).

We found a significant association between alleles at genes in the human HLA locus and the formation of adalimumab immunogenicity and low adalimumab drug serum concentrations in large clinical studies of CD and UC patients. This work extends previous findings in CD to UC and directly shows a genetic association in patients with low drug concentrations. This work builds on existing literature to suggest that genetic screening could be a useful tool for clinicians concerned with patient anti-TNF immunogenicity.

SERENE CD (NCT02065570), SERENE UC (NCT02065622).

Inflammatory bowel disease (IBD) is a chronic condition affecting the gastrointestinal tract, primarily manifesting as ulcerative colitis (UC) or Crohn's disease (CD). Both inflammation and disruption of the intestinal epithelial barrier are key factors in IBD pathogenesis. Substantial evidence has revealed a significant association between aberrant immune responses and impairment of the intestinal epithelial barrier in IBD pathogenesis. The components of the intestinal epithelium, particularly goblet cells and Paneth cells, are crucial to gut homeostasis, as they secrete mucin, antimicrobial peptides (AMPs), and cytokines. Furthermore, impairment of epithelial integrity, which is regulated by tight junctions, is a hallmark of IBD pathology. While common treatments for IBD, such as anti-inflammatory drugs, target various signaling pathways with varying efficacies, therapeutic approaches focused on mucosal and epithelial barrier healing have been largely neglected. Moreover, high costs, side effects, and insufficient or inconsistent therapeutic outcomes remain major drawbacks of conventional anti-IBD drugs. Recent studies on epithelial barrier regeneration and permeability reduction have introduced promising therapeutic targets, including farnesoid X receptor (FXR), urokinase-type plasminogen activator (uPA)-urokinase-type plasminogen activator receptor (uPAR) interaction, fecal microbiota transplantation (FMT), and insulin receptor (INSR). Notably, the simultaneous targeting of intestinal inflammation and promotion of epithelial barrier healing shows promise for efficient IBD treatment. Future research should explore targeted therapies and combination treatments, including natural remedies, microbiota colonization, stem cell approaches, and computer-aided drug design. It is also crucial to focus on accurate prognosis and developing a thorough understanding of IBD development mechanisms.

Although biologics have been revolutionizing the treatment of inflammatory bowel diseases (IBD) over the past decade, a significant number of patients still fail to benefit from these drugs. Overcoming the nonresponse to biologics is one of the top challenges in IBD treatment. In this study, we revealed that hyaluronan (HA), an extracellular matrix (ECM) component in the gut, is associated with nonresponsiveness to infliximab and vedolizumab therapy in patients with IBD. In murine colitis models, inhibition of HA synthase 2-mediated (HAS2-mediated) HA synthesis sensitized the therapeutic response to infliximab. Mechanistically, HA induced the expression of MMP3 in colonic fibroblasts by activating STAT3 signaling, thereby mediating the proteolytic cleavage of multiple IgG1 biologics. Finally, we found that macrophage-derived factors upregulated HAS2 expression in fibroblasts, thereby contributing to infliximab nonresponse. In summary, we identified a pathogenic connection between abnormal ECM remodeling and biologics nonresponse and provided insights for the precise therapy for IBD.

Data regarding the utility of therapeutic drug monitoring with ustekinumab (UST) are sparse. Our aim was to determine the correlation of UST levels with outcomes in a cohort of patients with inflammatory bowel disease (IBD).

This was a multicenter, retrospective study of all patients with IBD who received UST from January 1, 2014 to March 1, 2022. The primary outcomes were the correlation of UST level with clinical remission (per physician global assessment), endoscopic healing [the absence of ulcers/erosions in Crohn's disease (CD) and Mayo endoscopic score ≤1 for ulcerative colitis (UC)], and normal serum C-reactive protein (CRP) (≤5 mg/L). Secondary outcomes included defining optimal UST trough levels associated with favorable outcomes.

A total of 71 patients (74.6% with CD; 57.7% female) were included. The median age was 39.5 years [interquartile range (IQR): 26 to 52] and 12.6% were on combination therapy with immunomodulators. Median UST trough levels were significantly higher in patients who achieved endoscopic healing at 5.4 µg/mL versus 3.5 µg/mL ( P =0.035) and normal CRP at 5.5 µg/mL versus. 3.1 µg/mL ( P =0.002). A cutoff UST level of 4.8 µg/mL yielded the highest area under the curve (AUC) of 0.73 (95% CI: 0.61-0.80) to predict a normal CRP followed by a cutoff of 3.5 µg/mL which yielded an AUC of 0.66 (95% CI: 0.52-0.81) to predict endoscopic healing.

UST trough levels were significantly higher in patients who achieved a normal CRP and endoscopic healing. A cutoff UST level of 4.8 µg/mL reliably predicted CRP normalization.

The introduction of tumor necrosis factor inhibitors has led to a paradigm shift in the management of inflammatory bowel disease (IBD). The subsequent introduction of both anti-integrins and cytokine blockers has since expanded the biologic armamentarium. However, immunogenicity, defined as the production of anti-drug antibodies (ADAs) to the prescribed biopharmaceutical, means a significant fraction of patients exposed to biologic agents will experience a secondary loss of response to one or more of the drugs. In clinical settings, immunogenicity may be caused by several factors, both patient related (e.g., underlying chronic disease, systemic immune burden, including previous biologic therapy failure, and [epi]genetic background) and treatment related (e.g., dose and administration regimens, drug physical structure, photostability, temperature, and agitation). Here, we outline these elements in detail to enhance biopharmaceutical delivery and therapy for patients with IBD. Moreover, concurrent immunomodulator medication may reduce the risks of ADA generation, especially when using the chimeric drug infliximab. Summarizing the latest developments and knowledge in the field, this review aims to provide strategies to prevent ADA production and information on managing non-responsiveness or loss of response to biologics. Better understanding of the molecular mechanisms underlying the formation of ADAs and the critical factors influencing the immunogenicity of biopharmaceuticals may lead to improved health outcomes in the IBD community that may benefit both the individual patient and society through lower healthcare expenses.

Therapeutic drug monitoring (TDM) for biologic therapies in inflammatory bowel disease (IBD) primarily aims to optimize dosing. However, several unmet needs remain. These include the identification of optimal drug concentrations, accounting for variability in pharmacokinetics (PK) and pharmacodynamics (PD), and the frequent delays between sampling and clinical decision-making. Recent technical advances, such as population PK/PD modeling and model-informed precision dosing (MIPD) tools developed from such models, as well as point-of-care (POC) and self-sampling assays and novel software programs, offer potential solutions. Successful implementation of these innovations may help to establish MIPD for patients with IBD. This would enable personalized dosing, advancing a one-size-fits-all approach to TDM that currently is inadequate to fulfill the needs for every patient with IBD.

Antinuclear antibodies (ANAs) are critical immunological markers commonly associated with various connective tissue diseases (CTDs). However, these autoantibodies are also detectable in healthy individuals, patients with non-rheumatic autoimmune diseases, those with viral infections, and subjects using specific medications (such as procainamide, hydralazine, and minocycline) that can lead to drug-induced ANA elevation. The standard method for ANA detection is indirect immunofluorescence, a process that requires precision and thoroughness as it assesses both titer and fluorescence patterns. Additionally, immunoblotting and enzyme-linked immunosorbent assay (ELISA) are recommended to identify specific ANAs precisely, highlighting the importance of precision in ANA detection. This review explores the advantages and limitations of current ANA detection methods. It also describes the clinical implications of ANA presence in non-rheumatic diseases, including autoimmune disorders, infectious conditions, non-autoimmune and non-infectious diseases, and autoimmune cutaneous diseases. The presence of elevated ANA titers in these contexts can complicate clinical decision-making, as the diagnostic value of ANA testing alone is limited in non-rheumatic conditions. However, despite these limitations, ANA remains a key component in diagnosing and prognosis systemic CTDs, as it can indicate disease activity, severity, and response to treatment, which is of utmost importance in rheumatology and internal medicine. This paper provides a comprehensive review of the role of ANA in non-rheumatic diseases. It focuses on ANA diagnostic and prognostic significance and offers valuable insights for clinical practice.

Crohn's disease (CD) involves immune system interactions with intestinal tissue, driven by pro-inflammatory cytokines like Tumor Necrosis Factor (TNF-α). Adalimumab, targeting TNF-α, regulates associated inflammatory responses. Despite being humanized, it may induce immunogenic processes, affecting treatment effectiveness. Thus, monitoring serum adalimumab and anti-drug antibody (ADA) levels can optimize therapy. Understanding genetic factors influencing adalimumab response can enhance personalized treatment and improve patient quality of life. We aimed to quantify adalimumab serum levels, assess test interchangeability, detect ADA, examine immune complex formation, and investigate genetic phenotypes related to immunogenicity in CD patients. Seventy CD patients in the maintenance phase with adalimumab were classified into active (CDA) and remission (CDR) groups. Adalimumab concentration was determined via enzyme-linked immunosorbent assay (ELISA-Promonitor) and lateral flow assay (Quantum Blue), with assay interchangeability assessed statistically. ADA and immune complex formation were quantified using ELISA assays. DNA was genotyped for the genes ATG16L1, CD96, and CD155. No significant differences in adalimumab serum concentrations were observed between groups, regardless of the assay. However, a statistical difference between the tests indicated measurement disparity (P = 0.003), with moderate agreement (Lin's correlation of 0.247). ADA was detected in 4 of 27 of the patients with infratherapeutic levels, 3 in the CDA group and 1 in the CDR group. Analysis of immune complexes revealed significantly higher concentrations in the CDA group (P = 0.0125). The genotypic evaluation revealed significant associations for the CD96 CC (wild-type) genotype with higher CRP levels, colonic involvement, and infratherapeutic levels of adalimumab. ATG16L1 CC genotype was associated with higher CDEIS and fecal calprotectin values, while the variant (TT) genotype had lower platelet counts. The effectiveness of treatment with adalimumab was not directly related to higher medication levels in this cohort. The disparity between tests indicates the need to use only one test in patient follow-up to ensure accuracy in therapeutic monitoring. Genotypic differences highlight the correlation between the wild genotype for CD96 and ATG16L1 with unfavorable laboratory and endoscopic response to adalimumab. Finally, the more significant levels of immune complexes in the CDA group indicate an association with a worse response to adalimumab.

Herein, we described a case of small bowel Crohn's disease with recurrent, unexplained fevers, pain in the right lower back, hip, and groin area over 20 months. The patient did not present any gastrointestinal symptoms and colonoscopy showed no abnormalities. Imaging revealed a liver abscess and multiple lesions with pneumatosis in the muscles of the right lower back region. Initially, disseminated infection was suspected and the antibiotics was administered without success. Subsequently, Magnetic resonance (MR) enterography suggested the possibility of a small bowel fistula which was confirmed during exploratory laparotomy. Inflammation was prominent in a 27-cm segment starting from 30-cm proximal to the ileocecal junction. The segment was resected and pathological examination confirmed Crohn's disease. Postoperatively, mesalazine was administered, but showed limited efficacy. After modifying the treatment plan to infliximab and azathioprine, the patient was symptom-free and no obvious inflammation was found in the colonoscopy reexamination.

This study evaluated the long-term effectiveness and safety of a multidisciplinary early proactive therapeutic drug monitoring (TDM) program combined with Bayesian forecasting for infliximab (IFX) dose adjustment in a real-world dataset of paediatric patients with inflammatory bowel disease (IBD).

A descriptive, ambispective, single-centre study of paediatric patients with IBD who underwent IFX serum concentration measurements between September 2015 and September 2023. The patients received reactive TDM before September 2019 (n = 17) and proactive TDM thereafter (n = 21). We analysed for clinical, biological, and endoscopic remission; treatment failure; hospitalisations; emergency visits; and adverse drug reactions. The IFX doses were adjusted to maintain trough concentrations ≥ 5 µg/mL, with specific targets for proactive TDM.

Of the 38 patients, 21 had Crohn's disease (CD), 16 ulcerative colitis (UC), and 1 undetermined IBD. The mean (standard deviation) IFX trough concentrations were 6.83 (5.66) µg/mL (reactive) and 12.38 (9.24) µg/mL (proactive) (p = 0.08). No statistically significant differences between groups were found in remission rates or treatment failure. The proactive group had fewer hospitalisations (14.29% vs. 23.53%; p = 0.47) and shorter median hospitalisation days (6 vs. 19; p = 0.50), although the difference was not statistically significant. The number of patients with adverse reactions (infusion related reactions and infections) was higher in the proactive group (38.10% vs. 23.53%; p = 0.34) but the difference was not significantly different.

Proactive TDM showed no significant differences in treatment outcomes compared to reactive TDM. However, the results in both the reactive and proactive TDM groups were not worse than those reported in other studies. Further studies with larger samples are needed to optimize the treatment strategies for pediatric IBD patients.

Crohn's disease (CD), as a chronic systemic inflammatory disease, is strongly associated with the development of premature atherosclerosis (AS). Atherosclerotic cardiovascular disease, including coronary heart disease, myocardial infarction and stroke, is a lethal complication of CD. Nowadays, there is a lack of effective monotherapy for CD complicated by AS.

To explore the underlying effects and mechanisms of Xue-Jie-San (XJS) on treating CD complicated by AS via network pharmacology and experimental validation.

The targets of XJS components were obtained from TCMSP, ETCM and PubChem databases as well as the disease genes of CD and AS from GeneCards, DisGeNET and OMIM databases. The core targets were screened out from the drug-disease common targets identified by protein-protein interaction (PPI) network analysis and then analyzed with GO and KEGG enrichment. The interaction between core target and XJS component was detected by molecular docking and molecular dynamics simulation. Subsequently, the core targets were validated via GEO datasets and their biological functions were confirmed in vitro. Nile red staining was used to evaluated lipid accumulation in human umbilical vein endothelial cells (HUVECs) challenged by lipopolysaccharide (LPS) combined with oxidized low-density lipoprotein (ox-LDL). Levels of pro-inflammatory cytokines were examined by enzyme-linked immunosorbent assay. Chemokine CCL2 and CXCL8 were detected by immunofluorescence staining. The activity of the TLR4/Myd88/NF-κB signaling pathway was assessed using Western blot.

In total, 26 common target genes of XJS, CD and AS were found. Among them, 11 core genes were identified by PPI network analysis. The effects of XJS treating CD complicated by AS were mainly mediated by the lipid and atherosclerosis pathway, inflammatory bowel disease pathway and toll-like receptor signaling pathway. Molecular docking and molecular dynamics simulation displayed strong binding affinity between XJS component and the core target. Six core genes including TLR4, IL-1β, TNF, ICAM1, CCL2 and CXCL8 were validated by GEO datasets. In vitro, the effects of XJS on reducing lipid accumulation, secretion of IL-1β, IL6, TNF-α, CCL2 and CXCL8, and the protein expressions of TLR4, Myd88, p-p65 and ICAM1 were verified.

XJS is a potential candidate drug for the treatment of CD complicated by AS. The underlying mechanisms involve mitigation of lipid accumulation-mediated endothelial dysfunction and blockage of immune inflammatory response by targeting TLR4.

Background: Ustekinumab (UST) is an interleukin-12/interleukin-23 receptor antagonist approved for the treatment of Crohn's disease (CD). Only limited real-life data on the long-term outcomes of CD patients treated with UST are available. This study assessed UST's long-term effectiveness and safety in a large population-based cohort of moderate to severe CD patients. Methods: This was a multicenter, retrospective, observational cohort study that included both naïve and biologic-experienced patients treated with UST who achieved clinical remission or clinical response after at least one year of treatment. Clinical activity was scored according to the Harvey-Bradshaw Index (HBI). The primary endpoints were the maintenance or achievement of clinical remission after a further 12-month period of treatment, defined as an HBI of ≤5, and safety. Other endpoints included steroid-free remission, mucosal healing (MH), steroid discontinuation, and the need for treatment optimization during the follow-up. Results: Out of 562 CD patients, after an overall 24-month follow-up, clinical remission was present in 450 (80.0%) patients, and at 12 months, clinical remission was observed in 417/437 (95.4%) patients; 33/125 (26.4%) showed clinical response at 12 months (p = 0.000). A total of 38/103 (36.9%) patients achieved MH. Only 2.1% (12/562), 3% (17/562), and 1.1% (6/562) of patients required surgery, optimization, and re-induction, respectively. Adverse events occurred in eight patients (1.42%). According to a multivariate analysis, the only predictor of long-term remission was the presence of remission at the 12-month follow-up (p = 0.000). Conclusions: Long-term treatment with UST presents good efficacy and safety profiles in CD patients, especially for patients who achieve remission after one year.