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

Comparative efficacy of subcutaneous infliximab switching in remission and non-remission patients with inflammatory bowel disease after intravenous maintenance: 1-year outcome from a multicentre cohort study

Background

Elective switching from intravenous (IV) to subcutaneous (SC) infliximab (IFX) has shown efficacy in patients with inflammatory bowel disease (IBD). However, long-term outcomes for patients not in remission remain unclear.

Objectives

We evaluated the effectiveness of SC IFX switching in both remission and non-remission patients.

Design

This study was a retrospective multicentre study conducted across five tertiary hospitals in Korea.

Methods

Patients with IBD who switched to SC IFX between January 2021 and January 2023 were included. Clinical remission was defined as a Crohn's Disease Activity Index of <150 or a partial Mayo score of <2. Biochemical remission was defined as faecal calprotectin of <250 µg/g and C-reactive protein of <0.5 mg/dL. We investigated the treatment persistence rate of SC IFX and trends in pharmacokinetics, clinical indices and biomarkers over 1 year of follow-up, analysing the data based on the baseline remission state.

Results

Among 127 patients included, 90 (70.9%) were in clinical remission, and 37 (29.1%) were not at the time of switching. The one-year treatment persistence rate was 92.1%, with no significant difference between the clinical remission and non-remission groups (p = 0.139). Persistence was also unaffected by baseline biochemical remission status. IFX pharmacokinetics and biomarkers improved significantly in both clinical groups over 12 months (p < 0.005). Disease activity indices remained stable in the remission group and decreased in the non-remission group after switching. Previous biologics exposure was the only significant predictor of treatment persistence (hazard ratio, 5.634; 95% confidence interval, 1.357-23.384; p = 0.017). Adverse events related to SC IFX occurred in 15.7% of patients. The optimal SC IFX cutoff levels associated with clinical and biochemical remission were 11 and 17 μg/mL, respectively.

Conclusion

Switching from IV to SC IFX during maintenance therapy demonstrated high treatment persistence and safety, irrespective of clinical and biochemical remission status.

HLA-DQA1*05 Allele Carriage and Anti-TNF Therapy Persistence in Inflammatory Bowel Disease

INTRODUCTION

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.

METHODS

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).

RESULTS

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).

CONCLUSIONS

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.

Intestinal tissue levels of anti-TNF alpha, antibodies, and cytokines in paediatric Crohn disease

The aim was to explore factors associated with intestinal tissue levels of anti-TNF alpha (anti-TNF), anti-TNF antibodies, and cytokines in pediatric patients with Crohn Disease (CD). In a prospective exploratory study of CD patients undergoing ileocecal resection or colonoscopy between 6/2020 and 1/2023, we analysed tissue levels of anti-TNF, anti-TNF antibodies, and cytokines (TNF-α, IL-17, IL-1β, IFN-γ) from intestinal biopsies. Mixed-effects regression models, adjusted for potential confounders, were used. Data from 27 CD patients (18 females, 66.7%) were analysed. Fourteen (52%) received adalimumab (ADA) and thirteen received infliximab (IFX), with a median therapy duration of 17 (IQR 4.5-41.5) months. Higher levels of free anti-TNF were found in macroscopically inflamed tissue compared to non-inflamed tissue (β = 3.42, 95% CI 1.05-6.10). No significant association was found between serum and tissue anti-TNF levels (β= -0.06, 95% CI - 0.70-0.58). Patients treated longer with anti-TNF had increased IL-17 levels (β = 0.19, 95% CI 0.05-0.33), independent of disease duration and age. IFN-γ levels were linked with both follow-up duration and anti-TNF length. Our study shows significantly higher free drug levels in inflamed tissue. Long-term anti-TNF treatment has been linked to increased IL-17 levels, suggesting a possible impact on the cytokine response pathway. We did not observe a relationship between serum and tissue anti-TNF levels.

Immunogenicity of Therapeutic Antibodies Used for Inflammatory Bowel Disease: Treatment and Clinical Considerations

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.

Ileal Predominance in Crohn's Disease Is Associated With Increased Intestinal Surgery and Biological Therapy Use, With Lower Treatment Persistence

INTRODUCTION

Crohn's disease (CD) varies by location, potentially affecting therapy efficacy and surgery risk, although research on this topic is conflicting. This study aims to investigate the independent association between CD location and therapeutic patterns.

METHODS

We analyzed patients with CD diagnosed from January 2005 to May 2023 registered in the nationwide ENEIDA registry. A univariate Cox regression analysis assessed the association of disease location with biologic use and persistence (with treatment discontinuation as a failure event), as well as the use of intestinal resections. A multivariate model was constructed to evaluate the independent association of disease location with therapeutic patterns, controlling for potential confounders such as sex, age at inclusion and diagnosis, disease duration and behavior, previous surgery or biological therapy, extraintestinal manifestations, and perianal disease.

RESULTS

The study included 17,292 patients with a median follow-up period of 6 years (interquartile range 2-10 years). Ileocolonic location was associated with a higher biologic use than colonic location (hazard ratio [HR] 1.30, 95% confidence interval [CI] 1.22-1.38) and ileal disease (HR 1.21, 95% CI 1.16-1.27), independently predicting biologic use (P < 0.001). Ileal location was associated with a lower biologic persistence than ileocolonic location (HR 1.14, 95% CI 1.07-1.21) and colonic disease (HR 1.10, 95% CI 1.01-1.20), independently predicting biologic persistence (P = 0.019). Ileal disease was associated with a higher likelihood of intestinal resections than colonic (HR 2.82, 95% CI 2.45-3.25) and ileocolonic location (HR 1.13, 95% CI 1.05-1.22), independently predicting the use of surgery (P < 0.001).

DISCUSSION

CD location with ileal predominance is associated with a distinct therapeutic pattern, including higher biologic use, lower treatment persistence, and increased rates of intestinal resections.

Therapeutic drug monitoring and immunogenetic factors associated with the use of adalimumab in Crohn's disease patients

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.

Ultrasound transmural healing correlates with higher adalimumab drug concentration in Crohn's disease only in the short-term

BACKGROUND

anti-TNF drugs have revolutionized the treatment of Crohn's disease (CD) and have set new therapeutic targets. A direct correlation between anti-TNF trough levels and endoscopic healing in inflammatory bowel disease (IBD) patients has been established, but the association between drug levels and transmural healing assessed by ultrasound is not yet clearly defined.

AIMS

to evaluate the correlation between the serum concentration of adalimumab (ADA) and sonographic transmural healing in CD patients at different times during follow-up.

METHODS

in this retrospective, cross-sectional study, all patients with CD who were undergoing treatment with ADA in our center were included. Intestinal ultrasound (IUS) was performed before the initiation of the drug and for response monitoring. ADA serum-trough levels were compared between patients with and without transmural healing at different periods of time.

RESULTS

ninety-two patients were included, and all patients showed signs of inflammatory activity in the baseline IUS. During IUS monitoring of the response to ADA, 34 (34.8 %) patients presented transmural healing. Among patients in the first year of treatment, those with sonographic healing showed higher median levels than patients without transmural healing (12.0 µg/ml vs 9.3 µg/ml, respectively; p = 0.007). There was no correlation between ADA levels and sonographic healing in patients undergoing treatment for over a year.

CONCLUSIONS

higher ADA trough levels correlated with transmural healing with ultrasound during the first year of treatment. This correlation was not found after one year of treatment.

TL1A: A model for a precision medicine approach in the treatment of Crohn's disease and ulcerative colitis

Inflammatory bowel disease (IBD) is a collective term for chronic inflammatory diseases of the intestinal tract. The term IBD encompasses two main forms, Crohn's disease (CD) and Ulcerative colitis (UC). CD is characterized by inflammation throughout the length of the gut, especially the ileum and colon, and is often complicated with fistulae and/or intestinal strictures. Ulcerative colitis (UC) is inflammatory disease restricted to the colon and rectum. In practice however, IBD is a heterogenous disease with CD and UC representing the extremes of a continuum of diseases with varied clinical presentation, including disease location, severity, and manifestation of extraintestinal diseases. This disease heterogeneity poses a challenge to successful and efficacious therapeutic treatment as the etiology driving disease in individual patients is unknown and likely to be multifactorial, including genetic predisposition, environmental factors such as the microbiota, as well as social behaviors such as smoking and diet. Precision medicine provides a strategy to account for disease heterogeneity and diverse etiology to select for patients most likely to respond to a given therapeutic. In this chapter we present an example of the development of a novel antibody therapeutic, Tulisokibart, as a model for a Precision Medicine approach to the successful treatment of patients with IBD.

Persistence of subcutaneous versus intravenous infliximab in a real-life cohort: A propensity-score matched comparative analysis

BACKGROUND

There is limited comparative data on patients with inflammatory bowel disease (IBD) switched from intravenous to subcutaneous infliximab and those continuing intravenously. This study aimed to compare the persistence and tolerance of subcutaneous and intravenous infliximab and the outcomes of patients resuming intravenous infliximab.

METHODS

We conducted a retrospective single-centre cohort study involving IBD patients treated with maintenance intravenous infliximab. The switch to subcutaneous infliximab was offered to patients in clinical remission receiving an intravenous dose ≤ 10 mg kg-1 every ≥ 6 weeks. The switch group was compared to controls remaining on intravenous infliximab due to refusal of the switch.

RESULTS

With a median follow-up of 59 (46-67) weeks, subcutaneous infliximab was discontinued in 28/282 (10 %) patients and intravenous infliximab in 1/78 (1 %) patient (p = 0.01); after propensity score-matching of the two cohorts, persistence rates at 52 weeks were respectively 91 % (95 % CI 84-98) and 100 % (95 % CI 100-100, p = 0.01). Among the 28 who discontinued subcutaneous infliximab, 27 resumed intravenous infliximab, with 4 (1 % of the switch group) who permanently stopped infliximab.

CONCLUSION

Switching from intravenous to subcutaneous infliximab led to a lower treatment persistance. In cases of poor tolerance or relapse under subcutaneous infliximab, resuming intravenous infliximab is effective.

Sustainability of biologic treatment in paediatric patients with Crohn's disease: population-based registry analysis

BACKGROUND

We aimed to evaluate the predictors of sustainability of biologic drugs for paediatric patients with Crohn's disease (CD).

METHODS

The Czech National Prospective Registry of Biologic and Targeted Therapy of Inflammatory Bowel Disease (CREdIT) was used to identify the biologic treatment courses in paediatric patients with CD. Mixed-effects Cox models and propensity score analyses were employed to evaluate predictors of treatment sustainability.

RESULTS

Among the 558 observations of 473 patients, 264 were treated with adalimumab (47%), 240 with infliximab (43%), 41 with ustekinumab (7%), and 13 with vedolizumab (2%). Multivariable analysis revealed higher discontinuation risk with infliximab compared to adalimumab (HR = 0.600, 95%CI 0.389-0.926), both overall and in first-line treatment (HR = 0.302, 95%CI 0.103-0.890). Infliximab versus adalimumab was associated with shorter time to escalation (HR = 0.094, 95%CI 0.043-0.203). Propensity-score analysis demonstrated lower sustainability of infliximab (HR = 0.563, 95%CI 1.159-2.725). The time since diagnosis to treatment initiation (HR = 0.852, 95%CI 0.781-0.926) was the most important predictor. Baseline immunosuppressive therapy prolonged sustainability with infliximab (HR = 2.899, 95%CI 1.311-6.410).

CONCLUSIONS

Given the results suggesting shorter sustainability, the need for earlier intensification and thus higher drug exposure, and the greater need for immunosuppression with infliximab than with adalimumab, the choice of these drugs cannot be considered completely equitable.

IMPACT

Our study identified predictors of sustainability of biologic treatment in paediatric patients with Crohn's disease, including adalimumab (versus infliximab), early initiation of biologic treatment, and normalised baseline haemoglobin levels. Infliximab treatment was associated with earlier intensification, higher drug exposure, and a greater need for immunosuppression. Parents and patients should be fully informed of the disadvantages of intravenous infliximab versus adalimumab during the decision-making process. This study emphasises the importance of not delaying the initiation of biologic therapy in paediatric patients with Crohn's disease.

Comparative real-world outcomes between ustekinumab, infliximab, and adalimumab in bio-naïve and bio-experienced Crohn's disease patients: a retrospective multicenter study

BACKGROUND

Numerous studies have compared the efficacy of ustekinumab (UST) and anti-TNF agents [infliximab (IFX) or adalimumab(ADA)] in moderate to severe Crohn's disease (CD) patients. This study aims to compare the efficacy of UST, IFX, and ADA while differentiating between bio-naïve and bio-experienced patients, which is an underexplored aspect, particularly in Asia.

METHODS

We conducted a retrospective multi-center study from 2012 to 2023, categorizing patients into bio-naïve and bio-experienced groups. We evaluated clinical remission rates after induction therapy and clinical outcomes, including CD-related hospitalization, intestinal resection, and drug discontinuation during maintenance therapy.

RESULTS

Among the 214 bio-naïve CD patients, 60 received UST, 108 received IFX, and 46 received ADA. After 1:1 propensity score matching between UST and anti-TNF agents groups, 59 patients were analyzed in each group (45 in the IFX group and 14 in the ADA group). We found no significant differences in clinical remission rates (P = 0.071), CD-related hospitalization (P = 0.800), intestinal resection (P = 0.390), or drug discontinuation (P = 0.052) between the UST, IFX, and ADA groups in bio-naïve CD patients. In bio-experienced CD patients, with 35 in the UST group and 13 in the anti-TNF agents group, the UST group showed a lower risk of drug discontinuation (P = 0.004) than the anti-TNF agents group.

CONCLUSIONS

This study suggests that UST, IFX, and ADA are equally effective in bio-naïve CD patients, while in bio-experienced patients, mostly with previous exposure to anti-TNF agents, UST may offer superior drug durability.

Nanotechnology for Targeted Inflammatory Bowel Disease Therapy: Challenges and Opportunities

Inflammatory bowel disease (IBD) is a complex and recurring inflammatory disorder that affects the gastrointestinal tract and is influenced by genetic predisposition, immune dysregulation, the gut microbiota, and environmental factors. Advanced therapies, such as biologics and small molecules, target diverse immune pathways to manage IBD. Nanoparticle (NP)-based drugs have emerged as effective tools, offering controlled drug release and targeted delivery. This review highlights NP modifications for anti-inflammatory purposes, utilizing changes such as those in size, charge, redox reactions, and ligand-receptor interactions in drug delivery systems. By using pathological and microenvironmental cues to guide NP design, precise targeting can be achieved. In IBD, a crucial aspect of NP intervention is targeting specific types of cells, such as immune and epithelial cells, to address compromised intestinal barrier function and reduce overactive immune responses. This review also addresses current challenges and future prospects, with the goal of advancing the development of NP-mediated strategies for IBD treatment.

Effectiveness of Switching to Subcutaneous Infliximab in Ulcerative Colitis Patients Experiencing Intravenous Infliximab Failure

Background/Aims

Studies on elective switching to the subcutaneous (SC) formulation of infliximab revealed comparable efficacy and safety and higher infliximab level than those exhibited by intravenous (IV) infliximab. However, no studies have reported on the effectiveness of SC switching in ulcerative colitis (UC) patients who experienced IV infliximab failure during maintenance treatment.

Methods

This retrospective study included UC patients who had been switched to SC infliximab because of IV infliximab failure, between January 2021 and January 2023. Group A was defined as having clinically and biochemically active UC (secondary loss of response), and group B consisted of patients with stable symptoms but biochemically active UC.

Results

Twenty-three patients met the inclusion criteria: 15 in group A and eight in group B. The serum infliximab levels significantly increased after SC switching in both groups. The electively switched group also exhibited increased infliximab levels after SC switching. Patients in group A showed improved partial Mayo score with a significant decrease in fecal calprotectin and C-reactive protein after switching. In group B, the fecal calprotectin level significantly decreased without clinical relapse after switching. A high proportion of patients (≥80%) in both groups achieved clinical and/or biochemical responses at the last follow-up. During the follow-up period, only two patients in group A discontinued SC infliximab, and only one complained of severe injection site reaction.

Conclusions

In UC patients who experience IV infliximab failure during maintenance treatment, switching to SC infliximab may be a promising option because of better efficacy and safety.

Complementary Therapeutic Effect of Fecal Microbiota Transplantation in Ulcerative Colitis after the Response to Anti-Tumor Necrosis Factor Alpha Agent Was Lost: A Case Report

In patients with ulcerative colitis (UC), the development of an antidrug antibody (ADA) to anti-tumor necrosis factor (TNF)α agent is a crucial problem which aggravates the clinical course of the disease, being cited as one of the most common causes for discontinuing anti-TNFα treatment. This is due to ADA eventually causing secondary LOR, leading to discontinuation of anti-TNFα treatment. Recently, research on the microbiome and relationship between worsening UC and dysbiosis has been conducted. Further, investigations on the association between the microbiome and secondary LOR are increasing. Here, we present the therapeutic effect of fecal microbiota transplantation (FMT) on a 42-year-old man with secondary LOR and high ADA levels. FMT has recently been used for the treatment of, and for overcoming, drug resistance through microbiome modification. Stool samples were collected from the patient before and 4 weeks after FMT. Symptoms, including hematochezia and Mayo endoscopy sub-scores, improved after FMT, while ADA levels decreased by one-third to less than half the value (29 ng/mL) compared to before FMT (79 ng/mL). Additionally, the trough level of infliximab became measurable, which reflects the improvement in the area under the concentration (AUC). Butyricicoccus, Faecalibacterium, Bifidobacterium, Ligilactobacillus, Alistipes, and Odoribacter, which regulate immune responses and alleviate inflammation, also increased after FMT. We report a case in which microbiome modification by FMT increased the AUC of anti-TNFα in a patient who developed secondary LOR during anti-TNFα treatment, thereby improving symptoms and mucosal inflammation.

Long-term effectiveness and acceptability of switching from intravenous to subcutaneous infliximab in patients with inflammatory bowel disease treated with intensified doses: The REMSWITCH-LT study

BACKGROUND

The long-term risk of relapse after switching from intravenous (IV) to subcutaneous (SC) infliximab remains unknown in inflammatory bowel disease (IBD).

AIMS

To assess the long-term effectiveness and acceptability of switching from IV to SC infliximab in patients with IBD treated with or without an intensified IV regimen.

METHODS

We extended the follow-up of the REMSWITCH study including patients with IBD in clinical remission who were switched from IV to SC infliximab (120 mg/2 weeks). Relapse was defined as clinical relapse or faecal calprotectin increase ≥150 μg/g compared to baseline.

RESULTS

After median follow-up of 18 [15-20] months, among 128 patients, rates of relapse were 13.8% (8/58), 18.4% (7/38), 35.3% (6/17) and 86.7% (13/15) at last follow-up (p < 0.001), in those receiving 5 mg/kg/8 weeks, 10 mg/kg/8 weeks, 10 mg/kg/6 weeks and 10 mg/kg/4 weeks at baseline, respectively. Among relapsing patients, dose escalation led to clinical remission in 82.1% (23/28). In multivariable analyses, factors associated with higher risk of relapse were IV infliximab 10 mg/kg/4 weeks (OR = 61.0 [6.1-607.0], p < 0.001) or 10 mg/kg/6 weeks (OR = 4.7 [1.1-20.2], p = 0.017), and decreased (OR = 5.6 [1.5-20.3], p = 0.004) or stable (OR = 5.0 [1.6-15.0], p = 0.009) serum levels of infliximab between baseline and first post-switch visit. Acceptability was improved at 6 months and did not decrease over time (6.9 ± 1.6 before the switch vs. 8.8 ± 1.3 at 6 months and 8.8 ± 1.3 at last follow-up; p < 0.001). No severe adverse events were reported.

CONCLUSIONS

Switching from IV to SC infliximab 120 mg every other week is safe and well accepted leading to low long-term risk of relapse. Tight monitoring and dose escalation should be recommended for patients receiving 10 mg/kg/6 weeks and 4 weeks, respectively.

A Real-World Comparison of Drug Trough Levels between Patients Experiencing a Secondary Nonimmune Loss of Response and Those Maintaining a Response to Infliximab on Long-Term Maintenance Therapy for Inflammatory Bowel Disease

INTRODUCTION

A secondary loss of response (LOR) to infliximab (IFX) therapy for inflammatory bowel disease (IBD) is typically associated with low IFX trough levels, often with high levels of neutralizing antibodies to IFX (ATI). A small subset of patients on long-term therapy experience a "nonimmune" LOR, without ATI and with desired IFX trough levels ≥5 μg/mL, regarded as a LOR to the mechanism of action of IFX. However, this currently accepted IFX goal level is largely derived from observations of patients within the first year of therapy and may not apply to those on treatment beyond 1 year.

METHODS

Retrospective review of all IBD patients receiving IFX infusions for ≥12 months with at least 1 IFX trough and ATI measurement beyond 12 months was conducted. Chart review of all patients with absent ATI and an IFX trough ≥5 μg/mL classifies as LOR versus non-LOR based on physician assessment, with a comparison of IFX troughs between the two groups.

RESULTS

Of 167 patients using IFX ≥12 months, 13 (7.8%) experienced a nonimmune secondary LOR. The mean duration of IFX use was over 3 years for both LOR and non-LOR patients. The mean IFX trough for those with LOR was greater than for those without LOR, 18.5 μg/mL versus 13.1 μg/mL, p = 0.110.

CONCLUSION

Our results did not demonstrate lower IFX levels among patients experiencing secondary nonimmune LOR on long-term therapy. Our results do not redefine the therapeutic IFX goal levels for those patients on long-term therapy and suggest that underdosing of IFX is not the cause of secondary LOR.

Long-term effectiveness and safety of anti-TNF in pediatric-onset inflammatory bowel diseases: A population-based study

BACKGROUND

Anti-TNF agents are the first biologic treatment option in inflammatory bowel disease (IBD). The long-term effectiveness of this strategy at the population level is poorly known, particularly in pediatric-onset IBD.

METHODS

All patients diagnosed with Crohn's disease (CD) or ulcerative colitis (UC) before the age of 17 between 1988 and 2011 in the EPIMAD population-based registry were followed retrospectively until 2013. Among patients treated with anti-TNF, the cumulative probabilities of anti-TNF failure defined by primary failure, loss of response (LOR) or intolerance were evaluated. Factors associated with anti-TNF failure were investigated by a Cox model.

RESULTS

Among a total of 1,007 patients with CD and 337 patients with UC, respectively 481 (48%) and 81 (24%) were treated with anti-TNF. Median age at anti-TNF initiation was 17.4 years (IQR, 15.1-20.9). Median duration of anti-TNF therapy was 20.4 months (IQR, 6.0-59.9). In CD, the probability of failure of 1st line anti-TNF at 1, 3 and 5 years was respectively 30.7%, 51.3% and 61.9% for infliximab and 25.9%, 49.3% and 57.7% for adalimumab (p = 0.740). In UC, the probability of failure of 1st line anti-TNF therapy was respectively 38.4%, 52.3% and 72.7% for infliximab and 12.5% for these 3 timepoints for adalimumab (p = 0.091). The risk of failure was maximal in the first year of treatment and LOR was the main reason for discontinuation. Female gender was associated with LOR (HR, 1.48; 95%CI 1.02-2.14) and with anti-TNF withdrawal for intolerance in CD (HR, 2.31; 95%CI 1.30-4.11) and disease duration (≥ 2 y vs. < 2 y) was associated with LOR in UC (HR, 0.37; 95%CI 0.15-0.94) in multivariate analysis. Sixty-three (13.5%) patients observed adverse events leading to termination of treatment (p = 0.57). No death, cancer or tuberculosis was observed while the patients were under anti-TNF treatment.

CONCLUSION

In a population-based study of pediatric-onset IBD, about 60% in CD and 70% in UC experienced anti-TNF failure within 5 years. Loss of response account for around two-thirds of failure, both for CD and UC.

Sarcopenia assessed by computed tomography or magnetic resonance imaging is associated with the loss of response to biologic therapies in adult patients with Crohn's disease

Sarcopenia occurs in patients with Crohn's disease (CD). However, the association between sarcopenia and loss of response (LOR) to biologic agents remains unclear. This study explored such an association in CD patients. This retrospective study included 94 CD patients who received biologic therapy. The skeletal muscle cross-sectional area at the third lumbar was assessed by computed tomography or magnetic resonance imaging for sarcopenia evaluation. A LOR was defined by fecal calprotectin (FC) < 250 μg/g or >50% reduction from baseline levels or other factors, such as the used agent being replaced by other biologic agents. The association between sarcopenia and LOR was assessed by logistic regression analysis. LOR was observed in 54 patients (57.4%). The prevalence of sarcopenia in the LOR group was higher than that in response group (70.4% vs. 40.0%, p = 0.003). Sarcopenia (odds ratio [OR] = 3.89, 95% confidence interval [CI]: 1.31-11.54), Montreal L1 type (OR = 0.20, 95% CI: 0.06-0.60), perianal lesions (OR = 4.08, 95% CI: 1.31-12.70), and monocytes percentage (OR = 1.27, 95% CI: 1.02-1.57) at baseline were independent associated factors for LOR. Sarcopenia was also associated with LOR in patients who received infliximab (OR = 3.31, 95% CI: 1.11-9.87). Montreal L1 type, perianal lesions, and monocytes percentage (Model 1), and with additional consideration of sarcopenia (Model 2), were developed to predict LOR. Model 2 showed better performance than Model 1 (area under the curve [AUC] 0.82 vs. 0.75). Sarcopenia was associated with the LOR to biological agents or infliximab in adult patients with CD.

Systematic Review and Meta-analysis: Loss of Response and Need for Dose Escalation of Infliximab and Adalimumab in Ulcerative Colitis

BACKGROUND

Loss of response to infliximab or adalimumab in ulcerative colitis occurs frequently, and dose escalation may aid in regaining clinical benefit. This study aimed to systematically assess the annual loss of response and dose escalation rates for infliximab and adalimumab in ulcerative colitis.

METHODS

A systematic search was conducted from August 1999 to July 2021 for studies reporting loss of response and dose escalation during infliximab and/or adalimumab use in ulcerative colitis patients with primary response. Annual loss of response, dose escalation rates, and clinical benefit after dose escalation were calculated. Subgroup analyses were performed for studies with 1-year follow-up or less.

RESULTS

We included 50 unique studies assessing loss of response (infliximab, n = 24; adalimumab, n = 21) or dose escalation (infliximab, n = 21; adalimumab, n = 16). The pooled annual loss of response for infliximab was 10.1% (95% confidence interval [CI], 7.1-14.3) and 13.6% (95% CI, 9.3-19.9) for studies with 1-year follow-up. The pooled annual loss of response for adalimumab was 13.4% (95% CI, 8.2-21.8) and 23.3% (95% CI, 15.4-35.1) for studies with 1-year follow-up. Annual pooled dose escalation rates were 13.8% (95% CI, 8.7-21.7) for infliximab and 21.3% (95% CI, 14.4-31.3) for adalimumab, regaining clinical benefit in 72.4% and 52.3%, respectively.

CONCLUSIONS

Annual loss of response was 10% for infliximab and 13% for adalimumab, with higher rates during the first year. Annual dose escalation rates were 14% (infliximab) and 21% (adalimumab), with clinical benefit in 72% and 52%, respectively. Uniform definitions are needed to facilitate more robust evaluations.

Suboptimal Outcomes and Retreatment Rate of Patients With Crohn's Disease After Forced Discontinuation of Biologics: A Nationwide Population-Based Study

Taiwan's National Health Insurance (NHI) program forced discontinuation of biologic use in Crohn's disease (CD) after a limited treatment duration, regardless of disease activity. This study investigated the retreatment rate and suboptimal outcomes (i.e., CD-related surgeries, hospitalizations, emergency room visits, and oral steroid flare-ups) after forced discontinuation. This retrospective cohort study was conducted using data from the NHI Database. Patients who received ≥40 weeks of biologic treatment followed by a forced discontinuation were included. The time of biologic retreatment and the cumulative incidence of suboptimal outcomes after the forced discontinuation as well as related risk factors were analyzed. Included were 215 patients (68% male). At the beginning of biologic therapy, the mean age (±SD) was 35.7 (±13.5) years, and the disease duration was 4.46 (±3.52) years. The median (interquartile range) biologic treatment duration was 57.86 (50.3-83.3) weeks. Within the first year after forced discontinuation, 67% of patients (n = 144) were retreated with a second course of biologics, and 53% of patients (n = 114) experienced at least one suboptimal outcome. The independent risk factors associated with the occurrence of suboptimal outcomes were CD-related emergency room visits and hospitalizations during biologic therapy (hazard ratio: 2.49; 95% confidence interval: 1.59-3.89). More than two-thirds of patients with CD required biological retreatment within 1 year after a forced discontinuation. The substantial proportion of patients with poor disease outcomes highlights the need to continue the biologic.

Predictors and optimal management of tumor necrosis factor antagonist nonresponse in inflammatory bowel disease: A literature review

Tumor necrosis factor-α (TNF-α) antagonists, the first biologics approved for treating patients with inflammatory bowel disease (IBD), are effective for the induction and maintenance of remission and significantly improving prognosis. However, up to one-third of treated patients show primary nonresponse (PNR) to anti-TNF-α therapies, and 23%-50% of IBD patients experience loss of response (LOR) to these biologics during subsequent treatment. There is still no recognized predictor for evaluating the efficacy of anti-TNF drugs. This review summarizes the existing predictors of PNR and LOR to anti-TNF in IBD patients. Most predictors remain controversial, and only previous surgical history, disease manifestations, drug concentrations, antidrug antibodies, serum albumin, some biologic markers, and some genetic markers may be potentially predictive. In addition, we also discuss the next steps of treatment for patients with PNR or LOR to TNF antagonists. Therapeutic drug monitoring plays an important role in treatment selection. Dose escalation, combination therapy, switching to a different anti-TNF drug, or switching to a biologic with a different mechanism of action can be selected based on the concentration of the drug and/or antidrug antibodies.

Effectiveness of Switching From Intravenous to Subcutaneous Infliximab in Patients With Inflammatory Bowel Diseases: the REMSWITCH Study

BACKGROUND AND AIMS

We assessed the effectiveness of switching from intravenous to subcutaneous infliximab in patients with inflammatory bowel diseases (IBDs) treated with or without intensified intravenous regimen.

METHODS

In this multicenter observational study, IBD patients in clinical remission (partial Mayo score ≤2 or Harvey-Bradshaw index ≤4) were switched to a unique dose of subcutaneous infliximab (120 mg every other week). Pharmacological and biological data were collected at baseline, visit 1 (4-8 weeks postswitch), visit 2 (8-16 weeks postswitch), and visit 3 (16-24 weeks postswitch). Relapse was defined as clinical relapse or fecal calprotectin increase ≥150 μg/g compared with baseline.

RESULTS

Among 184 eligible patients, 72.3% (n = 133 of 184) agreed to switch to subcutaneous infliximab. At visit 3, a relapse occurred in 10.2% (n = 6 of 59), 7.3% (n = 3 of 38), 16.7% (n = 3 of 18), and 66.7% (n = 10 of 15) (P < .001) of patients receiving 5 mg/kg every 8 weeks, 10 mg/kg every 8 weeks, 10 mg/kg every 6 weeks, and 10 mg/kg every 4 weeks, respectively. Dose escalation to 240 mg every other week led to recapture clinical remission in 93.3% (n = 14 of 15). Infliximab serum levels increased after the switch (P < .0001) except for patients receiving 10 mg/kg every 4 weeks. In multivariable analysis, 10 mg/kg every 4 weeks regimen (odds ratio, 12.4; 95% confidence interval, 1.6-98.4; P = .017) and fecal calprotectin >250 μg/g at baseline (odds ratio, 5.4; 95% confidence interval, 1.1-27.6; P = .042) had a higher risk of relapse as well as reduced (41.7%) or stable (36.8%) infliximab serum levels between baseline and visit 1 compared with increased serum levels (12.7%) (P = .020 and P = .019, respectively). Patients' acceptability (10-point scale) was improved by the switch (6.9 ± 1.6 vs 8.6 ± 1.4; P < .0001). No severe adverse event was reported.

CONCLUSIONS

Switching from intravenous to subcutaneous infliximab 120 mg every other week is safe and well accepted, leading to a low risk of relapse in IBD patients except for those receiving 10 mg/kg every 4 weeks requiring 240 mg every other week.

Comparative Effectiveness of Anti-TNF in Combination With Low-Dose Methotrexate vs Anti-TNF Monotherapy in Pediatric Crohn's Disease: A Pragmatic Randomized Trial

BACKGROUND & AIMS

Tumor necrosis factor inhibitors, including infliximab and adalimumab, are a mainstay of pediatric Crohn's disease therapy; however, nonresponse and loss of response are common. As combination therapy with methotrexate may improve response, we performed a multicenter, randomized, double-blind, placebo-controlled pragmatic trial to compare tumor necrosis factor inhibitors with oral methotrexate to tumor necrosis factor inhibitor monotherapy.

METHODS

Patients with pediatric Crohn's disease initiating infliximab or adalimumab were randomized in 1:1 allocation to methotrexate or placebo and followed for 12-36 months. The primary outcome was a composite indicator of treatment failure. Secondary outcomes included anti-drug antibodies and patient-reported outcomes of pain interference and fatigue. Adverse events (AEs) and serious AEs (SAEs) were collected.

RESULTS

Of 297 participants (mean age, 13.9 years, 35% were female), 156 were assigned to methotrexate (110 infliximab initiators and 46 adalimumab initiators) and 141 to placebo (102 infliximab initiators and 39 adalimumab initiators). In the overall population, time to treatment failure did not differ by study arm (hazard ratio, 0.69; 95% CI, 0.45-1.05). Among infliximab initiators, there were no differences between combination and monotherapy (hazard ratio, 0.93; 95% CI, 0.55-1.56). Among adalimumab initiators, combination therapy was associated with longer time to treatment failure (hazard ratio, 0.40; 95% CI, 0.19-0.81). A trend toward lower anti-drug antibody development in the combination therapy arm was not significant (infliximab: odds ratio, 0.72; 95% CI, 0.49-1.07; adalimumab: odds ratio, 0.71; 95% CI, 0.24-2.07). No differences in patient-reported outcomes were observed. Combination therapy resulted in more AEs but fewer SAEs.

CONCLUSIONS

Among adalimumab but not infliximab initiators, patients with pediatric Crohn's disease treated with methotrexate combination therapy experienced a 2-fold reduction in treatment failure with a tolerable safety profile.

CLINICALTRIALS

gov, Number: NCT02772965.

Free antibodies-to-infliximab are biomarker for predicting the effect of dose intensification in pediatric Crohn's disease patients with secondary loss of response

Background

Immunogenicity to antitumor necrosis factor alpha agents, such as infliximab (IFX), may lead to therapeutic failure.

Objectives

This study evaluated the relationship between free and total antibodies-to-infliximab (ATIs), trough levels (TLs) of IFX, and the response to dose intensification.

Design

We performed a prospective, observational study including pediatric patients with Crohn's disease (CD) receiving IFX maintenance therapy without dose intensification.

Methods

We compared clinical and laboratory outcomes according to the presence of free and total ATIs. Factors associated with response to IFX dose intensification were investigated by analyzing IFX TLs and free and total ATIs.

Results

Of the 98 patients, 9 patients had detectable free ATIs and 38 patients had total ATIs. Patients with free ATIs had significantly lower TLs (0.7 versus 5.1 µg/mL, p < 0.001) than patients without free ATIs. However, there was no difference in the IFX TLs according to the presence of total ATIs (p = 0.2523). Analysis of the 38 samples with total ATIs showed that response to dose intensification was significantly lower in patients with free ATIs than those without free ATIs (22.2% versus 65.5%, p < 0.001). In addition, free ATIs were the only factor with poor response to dose intensification [odds ratio (OR): 14.15, 95% confidence interval (CI): 1.31-151.97, p = 0.0140]. According to the receiver operating characteristic analysis, the optimal cutoff level indicating non-response to IFX dose intensification was 30.0 AU/mL for free ATIs concentration (area under curve, 0.792; 95% CI: 0.590-0.942; sensitivity, 60.0%; specificity, 96.7%; p = 0.0241).

Conclusion

Free ATIs, but not total ATIs, have a negative impact on the course of CD. Free ATIs are potential reliable biomarker for predicting the effect of dose intensification in patients with loss of response to IFX. Future studies based on serial and proactive therapeutic drug monitoring are required in the future.

Long-term effectiveness and safety of ustekinumab in Crohn's disease: a prospective cohort study

BACKGROUND

Real-world data showed that ustekinumab is an effective treatment for Crohn's disease for up to 52 weeks. Yet, long-term effectiveness and safety outcomes beyond 52 weeks are limited. This study aimed to evaluate the corticosteroid-free clinical remission for up to 104 weeks. Secondary aims were focused on biochemical disease, dosing adjustments and safety outcomes.

METHODS

This multicentre prospective cohort study enrolled Crohn's disease patients who started ustekinumab between May 2016 and September 2019. Participants had scheduled outpatient visits at week 0, 13, 26, 52 and 104. Data on clinical disease [Harvey Bradshaw Index (HBI) = 4 points = remission], biochemical disease (faecal calprotectin = 200 µg/g or C-reactive protein = 10 mg/l = remission), dose adjustments and adverse drug reactions (ADRs) were recorded.

RESULTS

We included 101 Crohn's disease patients. In all patients, the proportion of patients in corticosteroid-free clinical remission was 35 and 36% at week 52 and 104. Of patients achieving corticosteroid-free remission at week 52, more than half maintained corticosteroid-free remission throughout week 104. Biochemical remission rates were 25 and 30% at week 52 and 104, respectively. In the first year of treatment, 33% required their first dose escalation, and 15% in the second year. Overall, 7% of patients discontinued ustekinumab due to ADRs. Ustekinumab persistency rates were 68% at week 52 and 59% at week 104.

CONCLUSION

Ustekinumab is an effective and well-tolerated treatment for Crohn's disease. More than half of all patients continued ustekinumab treatment after 104 weeks whereas one-third achieved corticosteroid-free remission.

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

BACKGROUND & AIMS

Discontinuation of anti-tumor necrosis factor-α treatment (anti-TNF) (infliximab and adalimumab) in patients with inflammatory bowel disease (IBD) is associated with a high relapse risk that may be influenced by endoscopic activity at the time of stopping. We assessed the relapse rate after anti-TNF withdrawal in patients with endoscopic healing and studied predictors of relapse including the depth of endoscopic healing.

METHODS

This was a multicenter, prospective study in adult patients with Crohn's disease (CD), ulcerative colitis (UC), or IBD-unclassified (IBDU), with ≥6 months of corticosteroid-free clinical remission (confirmed at baseline) and endoscopic healing (Mayo <2/SES-CD <5 without large ulcers), who discontinued anti-TNF between 2018 and 2020 in the Netherlands. We performed Kaplan-Meier and Cox regression analyses to assess the relapse rate and evaluate potential predictors: partial (Mayo 1/SES-CD 3-4) versus complete (Mayo 0/SES-CD 0-2) endoscopic healing, anti-TNF trough levels, and immunomodulator and/or mesalamine use.

RESULTS

Among 81 patients (CD: n = 41, 51%) with a median follow-up of 2.0 years (interquartile range, 1.6-2.1), 40 patients (49%) relapsed. Relapse rates in CD and UC/IBDU patients were comparable. At 12 months, 70% versus 35% of patients with partial versus complete endoscopic healing relapsed, respectively (adjusted hazard rate [aHR], 3.28; 95% confidence interval [CI], 1.43-7.50). Mesalamine use was associated with fewer relapses in UC/IBDU patients (aHR, 0.08; 95% CI, 0.01-0.67). Thirty patients restarted anti-TNF, and clinical remission was regained in 73% at 3 months.

CONCLUSIONS

The relapse risk was high after anti-TNF withdrawal in IBD patients with endoscopic healing, but remission was regained in most cases after anti-TNF reintroduction. Complete endoscopic healing and mesalamine treatment in UC/IBDU patients decreased the risk of relapse.

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.

Discontinuation of Infliximab Therapy in Patients with Crohn's Disease

BACKGROUND: Whether infliximab therapy can be successfully discontinued after patients with Crohn’s disease have attained sustained, clinical, biochemical, and endoscopic remission is unknown. METHODS: We conducted a multicenter, randomized, double-blind, placebo-controlled withdrawal study of infliximab in patients with Crohn’s disease who were in clinical, biochemical, and endoscopic remission after standard infliximab maintenance therapy for at least 1 year. Patients were randomly assigned 1:1 to continue infliximab therapy or to receive matching placebo for 48 weeks. The primary end point was time to relapse. RESULTS: This study randomly assigned 115 patients to either the infliximab-continuation group or to the infliximab-discontinuation group. No relapses were observed among the 59 patients continuing infliximab, whereas 23 of 56 patients discontinuing infliximab experienced relapse. Time to relapse was significantly shorter among patients who discontinued infliximab than among those who continued infliximab (hazard ratio, 0.080; 95% confidence interval [CI], 0.035 to 0.186; P<0.001). At the end of the trial at week 48, relapse-free survival was 100% in the infliximab-continuation group and 51% in the infliximab-discontinuation group. The key secondary end point, time to loss of remission, was significantly shorter among patients discontinuing infliximab therapy than those continuing infliximab (hazard ratio, 0.025; 95% CI, 0.003 to 0.187; P<0.001). No unexpected adverse events were reported. CONCLUSIONS: Discontinuation of infliximab for patients with Crohn’s disease receiving long-term infliximab therapy and in clinical, biochemical, and endoscopic remission leads to a considerable risk of relapse. (Funded by the Nordic Trial Alliance [NordForsk], the Medical Fund of the Danish Regions [Regionernes Medicin og Behandlingspulje], the Danish Colitis-Crohn Association, and the A.P. Moller Foundation; ClinicalTrials.gov number, NCT01817426; EudraCT number, 2012-002702-51.)

Optimizing therapeutic drug monitoring in inflammatory bowel disease: a focus on therapeutic monoclonal antibodies

INTRODUCTION

Therapeutic drug monitoring (TDM) is useful for optimizing monoclonal antibodies (mAbs) for the treatment of immune-mediated inflammatory disorders including inflammatory bowel disease (IBD). However, TDM in clinical practice is still restricted by long turnaround times between sampling and results and the fact that dosing of mAbs to a target drug concentration is challenging due to high pharmacokinetic (PK) variability at both a population and patient level. Overcoming these barriers may be addressed by point-of-care (POC) assays, model-informed precision dosing (MIPD), and pharmacogenetics/pharmacogenomics.

AREAS COVERED

This review provides an overview of the optimization of TDM of mAbs in IBD including POC testing, MIPD, and pharmacogenetics.

EXPERT OPINION

Recent advances in sampling, quantification, and support of clinical decisions include POC assays and PK dashboards, which may allow for prompt and precise application of TDM in clinical practice. Future perspectives toward a more personalized implementation of TDM could include the incorporation of pharmacogenetics/pharmacogenomics to identify subgroups of patients who would benefit more from proactive TDM or combination therapy such as those prone to immunogenicity and/or accelerated drug clearance. However, there are still challenges regarding the implementation of these innovative approaches, and more data from prospective studies and randomized controlled trials are needed.