Loss of Infliximab Into Feces Is Associated With Lack of Response to Therapy in Patients With Severe Ulcerative Colitis

Biologics in the management of pediatric inflammatory bowel disease: When and what to choose

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.

Review Article: Albumin and Its Role in Inflammatory Bowel Disease: The Old, the New, and the Future

BACKGROUND

Circulating albumin concentrations are frequently measured in clinical practice. This review explores biochemical properties and physiological roles of albumin, its place in nutritional assessment, current understanding of perturbed circulating concentrations, and role in clinical management, with special focus on patients with inflammatory bowel disease (IBD).

METHODS

A detailed literature search was performed.

RESULTS

Albumin is synthesized by hepatocytes and comprises 3% of total body protein. It has a prolonged intravascular half-life (17-19 h) due to neonatal Fc-receptor-mediated salvage and has a multitude of physiological functions. Albumin homeostasis is affected in disease states often resulting in reduced level, which is not a direct marker of malnutrition. In patients with IBD, morbid albumin concentrations provide prognostic information, identification of nonintestinal conditions, guidance to the required aggressiveness of therapy and biologic dosage, monitoring of disease activity, and potential need for therapeutic escalation. Barriers to utilization of morbid albumin levels include the lack of consensus regarding cutoff values and the deficiency of high-quality data in this domain due to the retrospective design of the majority of studies. Serum levels hold greatest clinical potential in prognostication in acute severe ulcerative colitis. The premorbid level in the individual may provide insight into dosing of biologics and potentially enhance interpretation of morbid levels.

CONCLUSIONS

Understanding the physiology and pathophysiology of albumin is fundamental to interpreting its circulating levels. The clinical value of its measurement in patients with IBD may be undervalued, as it assists in evaluation of disease severity, prognosis, and therapeutic decision-making.

Vedolizumab serum trough concentrations with and without thiopurines in ulcerative colitis: The prospective VIEWS pharmacokinetics study

BACKGROUND

Ulcerative colitis (UC) is a chronic inflammatory condition requiring continuous treatment and monitoring. There is limited pharmacokinetic data on vedolizumab during maintenance therapy and the effect of thiopurines on vedolizumab trough concentrations is unknown.

AIM

To investigate the exposure-response relationship of vedolizumab and the impact of thiopurine withdrawal in UC patients who have achieved sustained clinical and endoscopic remission during maintenance therapy.

METHODS

This is a post-hoc analysis of prospective randomized clinical trial (VIEWS) involving UC patients across 8 centers in Australia from 2018 to 2022. Patients in clinical and endoscopic remission were randomized to continue or withdraw thiopurine while receiving vedolizumab. We evaluated vedolizumab serum trough concentrations, presence of anti-vedolizumab antibodies, and clinical outcomes over 48 weeks to assess exposure-response association and impact of thiopurine withdrawal.

RESULTS

There were 62 UC participants with mean age of 43.4 years and 42% were females. All participants received vedolizumab as maintenance therapy with 67.7% withdrew thiopurine. Vedolizumab serum trough concentrations remained stable over 48 weeks regardless of thiopurine use, with no anti-vedolizumab antibodies detected. Patients with clinical remission had higher trough concentrations at week 48. In quartile analysis, a threshold of > 11.3 μg/mL was associated with sustained clinical remission, showing a sensitivity of 82.4%, specificity of 60.0%, and an area of receiver operating characteristic of 0.71 (95%CI: 0.49-0.93). Patients discontinuing thiopurine required higher vedolizumab concentrations for achieving remission.

CONCLUSION

A positive exposure-response relationship between vedolizumab trough concentrations and UC outcomes suggests that monitoring drug levels may be beneficial. While thiopurine did not influence vedolizumab levels, its withdrawal may necessitate higher vedolizumab trough concentrations to maintain remission.

Anti-TNF nonresponse in ulcerative colitis: correcting for mucosal drug exposure reveals distinct cytokine profiles

INTRODUCTION

It remains unclear why up to 30% of ulcerative colitis (UC) patients do not respond to tumor necrosis factor inhibitors (TNFi). Validated biomarkers for nonresponse (N)R) are lacking. Most studies investigating underlying mechanisms do not differentiate between pharmacokinetic and inflammatory mechanisms. We therefore aimed to develop a framework to correct for mucosal drug exposure (MDE) and applied this to mucosal cytokine profiles previously linked to (N)R.

METHODS

In a prospective international cohort, we studied patients with active moderate-severe UC starting TNFi treatment. Patients underwent endoscopy before (baseline) and after induction treatment (follow-up). NR was defined as the absence of Mayo endoscopic subscore improvement by central read or need for colectomy. The ratio of mucosal concentrations of TNFi/TNF was used to define high or low MDE. Mucosal concentrations of interleukin-6 (IL-6), Oncostatin M (OSM), interleukin-10 (IL-10), and interleukin-12/23p40 (IL-12/IL-23p40) were measured.

RESULTS

Fifty-four UC patients were included (43 infliximab, 11 adalimumab) of whom 39 (72%) were endoscopic responders (after a median treatment of 62 days [48-96]). NR with high MDE had high IL-6 at both time points. R with low MDE exhibited low mucosal IL-10 at baseline. At follow-up, high OSM was associated with NR (irrespective of MDE) and high IL-12/IL-23p40 with R.

CONCLUSIONS

We incorporated MDE in mucosal cytokine research to avoid bias due to the insufficient presence of anti-TNF. When applied to mucosal cytokines previously linked to (N)R, IL-6 appears to drive inflammation in TNFi-resistant UC patients, while OSM seems to parallel inflammation and does not cause refractoriness.

Impact of Chronic Inflammatory Diseases on Clinical Pharmacokinetics of Antibody-Based Therapeutic Proteins

Antibody-based therapeutic proteins (TPs) emerged as a promising therapeutic modality for chronic inflammatory diseases. During clinical development, the impact of disease on pharmacokinetics (PK) should be carefully considered to reliably extrapolate PK from healthy volunteers (HVs) in early-phase studies to patients in later-phase studies. This paper aimed to provide an overview of the impact of chronic inflammatory diseases on the PK of antibody-based TPs. A literature search was conducted on Drugs@FDA and PubMed, yielding 30 TPs with author-drawn conclusions about PK differences between HVs and patients with inflammatory diseases. Nine out of 30 TPs suggested PK differences in patients with inflammatory diseases compared with HVs, and patients mostly appeared to have higher drug clearance or lower drug exposure compared with HVs. However, the remaining 21 TPs appeared to have no apparent PK differences between patients and HVs. Based on ratios of reported drug clearance in patients vs. HVs (N: 31 ratios for 22 TPs), the difference in TP clearance due to inflammatory diseases did not exceed twofold (mean clearance ratio: 1.23; standard deviation: 0.25), with the most noticeable difference (>50% higher clearance) observed in patients with inflammatory bowel diseases and rheumatoid arthritis. Covariate assessment in published population PK models of TPs revealed that higher baseline C-reactive proteins and lower baseline albumin levels tend to be correlated with higher TP clearance. Future investigation is necessary to further elucidate the mechanism behind the inflammatory disease-mediated PK differences.

Recent Advances in the Management of Acute Severe Ulcerative Colitis

Acute severe ulcerative colitis is a medical emergency requiring inpatient treatment with intravenous steroids. Approximately one-third of patients do not respond to steroids sufficiently and require medical rescue therapy. Infliximab and cyclosporine are equally effective rescue agents, though infliximab is often preferred by clinicians for ease of use and greater familiarity. The use of cyclosporine is becoming more frequent, however, in patients previously exposed to infliximab. Those patients not exhibiting an adequate response to rescue therapy require colectomy. There is increasing interest in modified medical treatment to rescue the need for surgery. Janus kinase inhibitors may provide benefits when used alongside steroids from admission or as a rescue agent, but further randomised trials are needed to clearly establish their role. Intensified dosing of infliximab when used as a rescue therapy has shown mixed results but seems sensible in patients with low albumin and high disease burden. In this review, we describe the current established treatment pathways and report newer developments and evolving concepts that may in the future improve the care of patients with acute severe ulcerative colitis.

Advancements in the management of pediatric inflammatory bowel disease

INTRODUCTION

The management of pediatric inflammatory bowel disease (PIBD) has drastically changed in the last decade. The limited availability of new biologics or small molecule therapies, and concerns about durability in children has necessitated the development of other advances in management to optimize care.

AREAS COVERED

This review covers guidance for management targets and advances in optimizing biologic therapies, new medical therapies, adjuvant therapies, precision medicine and mental health concerns in PIBD. This review focused on recent advances and was not intended as a complete overview of the investigations and management of pediatric IBD.

EXPERT OPINION

Advancements include standardization of treatment goals via a treat-to-target strategy, optimizing anti-TNF biologics through combination therapy or proactive drug monitoring, earlier initiation of treatment for Crohn's disease, the emergence of new biologic/advanced therapies and a growing focus on adjuvant therapies targeting the microbiome. Future progress relies on the inclusion of children/adolescents in clinical trials to facilitate faster regulatory approval for pediatric therapies and the integration of precision medicine and mental health screening to improve patient care and outcomes.

Infliximab Tissue Concentrations in Patients With Stable Ulcerative Colitis Are Correlated With More Durable Infliximab-associated Disease Remission

BACKGROUND

We aimed to determine the correlation between tissue and plasma infliximab concentrations in an outpatient ulcerative colitis (UC) cohort based on histologic disease activity in addition to their relationship with long-term clinical outcomes. We assessed intraparticipant variability in infliximab concentrations between adjacent intestinal samples and the correlation between disease activity and tumor necrosis factor-α (TNF-α).

METHODS

A prospective cohort study was conducted in participants with UC receiving infliximab. Blood and 2 sigmoid colon biopsies were obtained at the index colonoscopy for infliximab and TNF-α quantification. Histological disease activity was assessed. Participants were followed for 2 years for the occurrence of hospitalization, surgery, disease relapse, and infliximab discontinuation.

RESULTS

A positive correlation was observed between mean plasma and uninflamed tissue infliximab concentrations only (Rs = 0.75, P = .0071). Lower mean tissue infliximab concentrations correlated with a shorter time to disease relapse vs those with higher mean tissue concentrations (Rs = 0.77, P = .032). This was not seen when using plasma infliximab concentrations. Additionally, no significant intraparticipant variability of infliximab concentrations was observed for all participants independent of disease activity. Neither plasma nor tissue TNF-α correlated with disease activity.

CONCLUSIONS

These findings support data generated in patients with Crohn's disease: plasma infliximab concentrations are reflective of infliximab exposure in tissue in the UC patient in remission, but not for those with active disease. Increasing tissue concentrations in the noninflamed tissues may improve durability of infliximab. Neither plasma nor tissue TNF-α appear to correlate with UC disease activity. Larger follow-up studies would be of benefit.

Pediatric IBD Patients Treated With Infliximab and Proactive Drug Monitoring Benefit From Early Concomitant Immunomodulatory Therapy: A Retrospective Analysis of a 10-Year Real-Life Cohort

BACKGROUND

Limited approval of second-line treatments in pediatric inflammatory bowel disease (pIBD) necessitates optimized use of infliximab (IFX) with proactive therapeutic drug monitoring (TDM). We investigated whether early combo-therapy with an immunomodulator (IMM) provides additional benefit.

METHODS

In the retrospectively reviewed medical records of all children treated with IFX and proactive TDM between 2013 and 2022, IMMearly (IMM ≤3 months since IFX start) was evaluated against IMMother/no (late/short or no IMM) over follow-up of 3 to 60 months. Kaplan-Meier analysis was used to analyze time to loss of response (LOR) with IFX discontinuation or time to antibodies-to-IFX (ATI) development.

RESULTS

Three hundred fifteen patients with pIBD were reviewed; of those, 127 with 2855 visits were included (77 CD, 50 UC/IBD-unclassified). Sixty patients received IMMearly, 20 patients IMMother, and 47 had IFX monotherapy. Median follow-up time was 30 and 26 months for IMMearly and IMMother/no, respectively, with comparable proactive TDM. Infliximab treatment persistence was 68% after 60 months. Loss of response was observed in 7 IMMearly and 15 IMMother/no patients (P = .16). Early combo-therapy significantly delayed LOR with IFX discontinuation (median LOR free interval IMMearly 30 months vs IMMother/no 9 months, P = .01). Patients with IMMother/no were 10-, 3- and 2-times more likely to experience LOR with IFX discontinuation after 1, 3, and 5 years, respectively. There were no significant group differences regarding the presence of any positive (>10 arbitrary units per milliliter [AU/mL]) or high (>100 AU/mL) ATI, median ATI concentrations, and ATI-free interval.

CONCLUSIONS

Early IMM combo-therapy in proactively monitored patients with pIBD significantly prolonged the median LOR free interval compared with late/short or no IMM treatment.

An evaluation of mirikizumab for the treatment of ulcerative colitis

INTRODUCTION

Treatment of ulcerative colitis (UC) aims to reduce symptoms and complications by decreasing intestinal inflammation. A proportion of patients do not respond to, do not tolerate, or are inappropriate candidates for current therapies. Interleukin (IL)-23 is a therapeutic target and mirikizumabis the first p19-targeted IL-23 antibody approved for the treatment of moderately to severely active UC.

AREAS COVERED

This review summarizes the pro-inflammatory effects of IL-23 and outlines the pharmacokinetics of mirikizumab. It provides a synopsis of the available phase II and phase III evidence for the efficacy and safety of mirikizumab in UC.

EXPERT OPINION

The mirikizumab clinical development program demonstrated its superiority over placebo and its favorable safety profile in the treatment of UC. Its positioning in therapeutic algorithms remains to be fully understood but mirikizumab has proven efficacy in both advanced therapy (AT)-naïve and AT-experienced patients. The inclusion in the license of extended induction for non-responders as well as rescue intravenous dosing allows for flexibility in patient with limited primary response and secondary loss of response.

The therapeutic efficacy of adipose mesenchymal stem cell-derived microvesicles versus infliximab in a dextran sodium sulfate induced ulcerative colitis rat model

Ulcerative colitis (UC) is a chronic relapsing intestinal inflammation that is becoming of increasing incidence worldwide and has insufficient treatment. Therefore, finding effective therapies remains a priority. A dextran sodium sulfate colitis model was established to elucidate colonic layers alterations and compare adipose mesenchymal stem cell-derived microvesicles (MSC-MVs) versus infliximab (IFX) efficacy through biochemical, light, and electron microscope studies. Fifty-four rats were allocated to 4 groups: Control (Con), UC, UC+IFX, and UC+MSC-MVs groups. End body weights (BW) and serum malondialdehyde (MDA) levels were recorded. Colitis severity was estimated by disease activity index (DAI). Colonic specimens were processed to evaluate the histological structure, collagen content, surface mucous and goblet cells, CD44, TNF-α, and GFAP immune expression. Morphometric and statistical analyses were performed. The UC group revealed congested, stenosed colons, a significant decline in end BW, and a significant increase in serum MDA and DAI. Furthermore, disturbed histoarchitecture, inflammatory infiltration, depletion of surface mucous and goblet cells, increased collagen, and TNF-α expression and decreased GFAP expression were observed. Alterations were partially attenuated by IFX therapy, whereas MSC-MVs significantly improved all parameters. In conclusion, MSC-MVs were a superior therapeutic option, via attenuating oxidative stress and inflammatory infiltration, in addition to restoring intestinal epithelial integrity and mucosal barrier.

Infliximab Monotherapy vs Combination Therapy for Pediatric Crohn's Disease Exhibit Similar Pharmacokinetics

BACKGROUND

The use of concomitant azathioprine may improve efficacy and pharmacokinetic (PK) properties of infliximab (IFX) but is also associated with an increased risk of adverse events. Proactive therapeutic drug monitoring (pTDM) of IFX monotherapy is an alternative strategy to improve PK. The aim of this study was to evaluate whether IFX with an immunomodulator (combo) has PK benefits over IFX-pTDM (mono) in pediatric Crohn's disease (CD).

METHODS

This PK analysis included pediatric CD patients who started either IFX combo (TISKids study) or IFX mono with pTDM (REFINE cohort). Combo and mono IFX trough levels (TLs) and antibodies-to-infliximab were assessed at infusion 3, 4, and 5. A population PK model was built to compare IFX PK outcomes (clearance [CL], TLs and cumulative exposure) between combo and mono groups at infusion 4 and 5. Clinical response and steroid-free clinical remission (SFCR) was assessed at infusion 4 and 5.

RESULTS

This study included 128 pediatric CD patients (66 mono and 62 combo). At infusion 5, there was no significant difference between mono and combo median TLs 4.1 µg/mL (2.1, 7.8) vs 5.9 µg/mL (3.2, 9.4; P = .14) or median CL 0.26 L/d (0.21, 0.32) vs 0.26 L/d (0.21, 0.33; P = .81). Mono patients had a lower SFCR rate at infusion 5 (53% [31 of 59] vs 80% [32 of 40]; P = .01). Clinical response rates were significantly higher among combo than mono patients at both infusion 4 and 5.

CONCLUSIONS

This study suggests that there are no PK differences (TLs and CL) between combo and mono therapy in pediatric CD patients who started IFX.

Steroid-Refractory Acute Severe Ulcerative Colitis in Infliximab-Experienced Patients

Acute severe ulcerative colitis (ASUC) is a potentially life-threatening complication of ulcerative colitis (UC) that can lead to significant morbidity and mortality, with a substantial number of patients needing colectomy. Infliximab (IFX) has been increasingly used as a rescue therapy for patients who have failed intravenous steroids and has been more frequently used as an induction and maintenance therapy in moderate-to-severe UC. Therefore, the number of patients admitted with ASUC previously exposed to IFX has been increasing, raising additional challenges in the medical management of these patients to avoid emergent colectomy. This narrative review intends to summarise the most recent evidence in the medical management of steroid-refractory ASUC patients previously exposed to IFX and to propose a treatment algorithm for approaching this difficult-to-treat group of patients.

Therapeutic drug monitoring in inflammatory bowel disease: recent developments

INTRODUCTION

Therapeutic Drug Monitoring (TDM) has an important role in the management of inflammatory bowel disease (IBD) patients on infliximab (IFX) or adalimumab and is recommended in IBD patients presenting a loss of response under anti TNF agent. But, TDM was not recommended for others biotherapies.

AREAS COVERED

Analyzing all publications about TDM and biologics in IBD patients, we reported the major results for each biotherapy.

EXPERT OPINION

Emerging data suggest that TDM will probably be similarly useful forIFX SC. In contrast, there is no demonstrated clinical benefit to the use of TDM with golimumab. For vedolizumab results for the use of both reactive and proactive TDM are discordant. For ustekinumab, data supports the existence of an exposure response relationship, albeit of a lesser magnitude than with anti-TNF agents. Finally, recent data from small case series suggests that TDM could be valuable in optimizing anti-IL23 agents, particularly risankizumab, but this requires further clarification. Consistent with the new concept of 'proactive' strategy, recent data support the utility of dashboard-driven model informed precision dosing (MIDP) of anti-TNF agents, in particular infliximab. Dashboards are software systems using Bayesian population pharmacokinetic modelling to individualize recommendations for target drug levels.

Predicting Outcome after Acute Severe Ulcerative Colitis: A Contemporary Review and Areas for Future Research

Acute Severe Ulcerative Colitis (ASUC) is a severe form of ulcerative colitis relapse which requires hospitalization and intensive medical intervention to avoid colectomy. The timely recognition of patients at risk of corticosteroid failure and the early initiation of medical rescue therapy are paramount in the management of ASUC. The choice of medical rescue therapy is influenced by multiple factors, especially patient's prior treatment history. This decision should involve the patient and ideally a multidisciplinary team of healthcare professionals, including gastroenterologists, radiologists, surgeons and enterostomal therapists. Although several predictive models have been developed to predict corticosteroid failure in ASUC, there is no single validated tool that is universally utilized. At present, infliximab and cyclosporine are the only agents systematically evaluated and recommended for medical rescue therapy, with recent reports of off-label utilization of tofacitinib and upadacitinib in small case series. The available evidence regarding the efficacy and safety of these oral small molecules for ASUC is insufficient to provide definitive recommendations. Early decision-making to assess the response to medical rescue therapy is essential, and the decision to pursue surgery in the case of treatment failure should not be delayed.

What are the benefits of therapeutic drug monitoring in the optimization of adalimumab therapy? a systematic review and meta-analysis up to 2022

Aims

Persistent uncertainties exist surrounding the therapeutic drug monitoring (TDM) of adalimumab in clinical settings. To address these issues, we conducted a systematic review to assess the current evidence regarding the benefits of TDM for adalimumab.

Methods

PubMed, EMBASE, and Cochrane Databases were searched from inception to October 2022. The trials regarding to the list three key questions were considered: 1) Could routine proactive TDM assist in improving outcomes in patients receiving adalimumab? 2) Could reactive TDM assist in guiding subsequent treatment strategies for patients with treatment failure to adalimumab? 3) Could TDM assist in informing dose reduction or discontinuation in patients with low disease activity or in remission treated with adalimumab? Two reviewers independently selected the studies and extracted the data. Meta-analysis was performed to calculate the relative risk (RR) and 95% confidence interval (CI).

Results

A total of 9 studies was included in this review. For proactive TDM, meta-analysis indicated that proactive TDM (n = 163/257, 63.42%) showed no significant superiority over reactive TDM and/or conventional management (n = 336/606, 55.44%) in achieving and/or maintaining clinical remission by random effects model (RR: 1.24, 95% CI 0.98-1.58, I 2 = 73%). There were three studies that supporting the reactive TDM, low drug levels in the absence of anti-drug antibodies (ADA) strongly indicate the need for dose intensification, and infliximab is a feasible choice for patients with low drug levels and ADA positivity. While swapping to another class should be considered in patients with adequate drug levels. In addition, TDM can help clinicians optimize dosing schedules and prevent overtreatment in patients who have achieved low disease activity and sufficient drug concentrations, with no predictive value for successful adalimumab discontinuation.

Conclusion

Current evidence suggests that proactive TDM is numerically but not statistically significant superiority over reactive TDM and/or conventional management. Reactive TDM can aid in understanding treatment failure and developing subsequent therapy. For patients reaching low disease activity and remission, TDM can help successful dose reduction, while it cannot inform the successful drug discontinuation. However, existing trials are limited, and more well-designed trials are necessary to clarify the role of TDM in adalimumab treatment.

Population Pharmacokinetics of Adalimumab in Juvenile Idiopathic Arthritis Patients: A Retrospective Cohort Study Using Clinical Care Data

BACKGROUND AND OBJECTIVE

Juvenile idiopathic arthritis (JIA) is a chronic autoimmune disorder that primarily affects the joints in children. Notably, it is known to co-occur with uveitis. Adalimumab, a monoclonal anti-TNF antibody, is effective in treating both conditions. A deeper understanding of the pharmacokinetics (PK) of adalimumab in JIA is crucial to advance in more personalized treatment approaches. The objective of this study is to evaluate the population PK profile of adalimumab in JIA and to explain causes for its variability.

MATERIALS AND METHODS

Adalimumab and antidrug antibody concentrations were retrospectively retrieved from the charts of patients with JIA. Initially, five literature-based population PK models of adalimumab were evaluated to assess their ability to describe the observed concentration-time profiles in the JIA cohort. These models included one specifically for the pediatric Crohn's disease population and four derived from studies in adult populations in healthy subjects and rheumatoid arthritis patients. Subsequently, a novel population PK model tailored to the JIA population was developed using NONMEM software. Monte Carlo simulations were then conducted utilizing the final PK model to visualize the concentration-time profile of adalimumab in patients with JIA and the impact of covariates.

RESULTS

A cohort of 50 patients with JIA with 78 available adalimumab samples was assessed. The mean age was 11.8 ± 3.9 years, with a median body weight of 49 kg (interquartile range 29.4-59.8 kg). All literature models adequately described the concentration-time profiles in JIA. The best model, which was developed in patients with rheumatoid arthritis during the maintenance phase of treatment, served as a basis for estimating clearance in JIA, resulting in a value of 0.37 L per day per 70 kg. Patient body weight, antidrug antibodies, methotrexate use, CRP level, and comorbidity of uveitis were found to have a significant impact on adalimumab clearance, and these reduced the inter-patient variability from 58.6 to 28.0%. On steady state in the simulated patient population, the mean trough level was 7.4 ± 5.5 mg/L. The two dosing regimens of 20 and 40 mg every other week, based on patients' body weight, resulted in comparable simulated overall drug exposure.

CONCLUSIONS

Five literature models effectively described adalimumab PK in this pediatric cohort, highlighting the potential for extrapolating existing models to the pediatric population. The new JIA model confirmed the effect of several known covariates and found a novel association for drug clearance with methotrexate use (lower) and uveitis (higher), which might have clinical relevance for personalized dosing in JIA.

Comparison of accelerated and standard infliximab induction regimens in acute severe ulcerative colitis using propensity score analysis: a retrospective multicenter study in China

Background

The optimal regimen of infliximab salvage in acute severe ulcerative colitis (ASUC) patients remains controversial. This study aimed to compare accelerated and standard infliximab induction in Chinese ASUC patients, and to explore risk factors and concrete accelerated regimens for them.

Methods

Data were retrospectively collected from steroid-refractory ASUC patients receiving infliximab as rescue therapy at seven tertiary centers across China. Outcomes including colectomy and clinical remission (Mayo score ≤ 2 and every subscore ≤ 1 at Day 14) rates were compared between patients receiving accelerated and standard infliximab induction using propensity score adjustment for potential confounders. The dose-response relationship was explored by plotting restricted cubic splines. Logistic regression and Cox proportional hazards regression analyses were performed to determine risk factors for adverse outcomes. A systematic review and meta-analysis was also performed.

Results

A total of 76 patients were analysed: 29 received standard and 47 received accelerated induction. The accelerated group had a higher 90-day colectomy rate (17.8% vs 0%, P = 0.019) and lower clinical remission rate (27.7% vs 65.5%, P = 0.001). After adjusting for propensity score and institution, there was no significant difference in colectomy or clinical remission rates (both P > 0.05). Dose-effect curves showed decreased colectomy hazard with higher cumulative infliximab dosage within 5 days, with no improvement observed for increasing cumulative infliximab dosage within 28 days. Multivariate logistic regression analyses revealed C-reactive protein of >10 mg/L at infliximab initiation (odds ratio = 5.00, 95% confidence interval: 1.27-24.34) as an independent risk factor for no clinical remission. Meta-analysis also revealed no significant difference in colectomy rates at 3 months (P = 0.54).

Conclusions

After adjusting for confounders, there were no significant differences in colectomy or clinical remission rates between accelerated and standard infliximab induction among ASUC patients. Early administration of an intensified dosage within 5 days may be beneficial. Elevated C-reactive protein at infliximab initiation indicated need for intensive treatment.

Best Practice for Therapeutic Drug Monitoring of Infliximab: Position Statement from the International Association of Therapeutic Drug Monitoring and Clinical Toxicology

BACKGROUND

Infliximab, an anti-tumor necrosis factor monoclonal antibody, has revolutionized the pharmacological management of immune-mediated inflammatory diseases (IMIDs). This position statement critically reviews and examines existing data on therapeutic drug monitoring (TDM) of infliximab in patients with IMIDs. It provides a practical guide on implementing TDM in current clinical practices and outlines priority areas for future research.

METHODS

The endorsing TDM of Biologics and Pharmacometrics Committees of the International Association of TDM and Clinical Toxicology collaborated to create this position statement.

RESULTS

Accumulating data support the evidence for TDM of infliximab in the treatment of inflammatory bowel diseases, with limited investigation in other IMIDs. A universal approach to TDM may not fully realize the benefits of improving therapeutic outcomes. Patients at risk for increased infliximab clearance, particularly with a proactive strategy, stand to gain the most from TDM. Personalized exposure targets based on therapeutic goals, patient phenotype, and infliximab administration route are recommended. Rapid assays and home sampling strategies offer flexibility for point-of-care TDM. Ongoing studies on model-informed precision dosing in inflammatory bowel disease will help assess the additional value of precision dosing software tools. Patient education and empowerment, and electronic health record-integrated TDM solutions will facilitate routine TDM implementation. Although optimization of therapeutic effectiveness is a primary focus, the cost-reducing potential of TDM also merits consideration.

CONCLUSIONS

Successful implementation of TDM for infliximab necessitates interdisciplinary collaboration among clinicians, hospital pharmacists, and (quantitative) clinical pharmacologists to ensure an efficient research trajectory.

Therapeutic drug monitoring in inflammatory bowel diseases. Position statement of the Spanish Working Group on Crohn's Disease and Ulcerative Colitis

The treatment of inflammatory bowel disease has undergone a significant transformation following the introduction of biologic drugs. Thanks to these drugs, treatment goals have evolved from clinical response and remission to more ambitious objectives, such as endoscopic or radiologic remission. However, even though biologics are highly effective, a significant percentage of patients will not achieve an initial response or may lose it over time. We know that there is a direct relationship between the trough concentrations of the biologic and its therapeutic efficacy, with more demanding therapeutic goals requiring higher drug levels, and inadequate exposure being common. Therapeutic drug monitoring of biologic medications, along with pharmacokinetic models, provides us with the possibility of offering a personalized approach to treatment for patients with IBD. Over the past few years, relevant information has accumulated regarding its utility during or after induction, as well as in the maintenance of biologic treatment, in reactive or proactive strategies, and prior to withdrawal or treatment de-escalation. The aim of this document is to establish recommendations regarding the utility of therapeutic drug monitoring of biologics in patients with inflammatory bowel disease, in different clinical practice scenarios, and to identify areas where its utility is evident, promising, or controversial.

The Role of Tofacitinib in the Treatment of Acute Severe Colitis in Children

Objectives

Acute severe colitis (ASC) occurs in up to 15 percent of children with ulcerative colitis, with a high index of morbidity and mortality. Treatment includes high-dose steroids, infliximab, and salvage therapies. Unfortunately, up to 20 percent of patients may need an urgent colectomy due to treatment failure. We report our experience using tofacitinib for the treatment of six patients.

Methods

A retrospective review of our medical electronic records was conducted. We included every patient with ASC and treatment failure, in whom tofacitinib was used as a salvage therapy. Response, complications, and disease course were noted.

Results

Six patients were included with Pediatric Ulcerative Colitis Activity Index (PUCAI) scores ranging from 65 to 85 on admission, and 35 to 85 before tofacitinib was started (P 0.07). Median response time was 72 h. A median decrease of 40 points in PUCAI was noted (P 0.00001). Mean length of stay was 18 days with discharge 9 days after tofacitinib introduction. Haemoglobin, albumin, fecal calprotectin, and CRP improved after tofacitinib (P 0.02, P 0.02, P 0.025, and P 0.01, respectively). The mean follow-up was 8.5 months, four patients achieved complete remission and only one had a recrudescence of symptoms (P 0.01). One patient had a systemic Epstein-Barr virus infection prior to tofacitinib therapy, which resolved with rituximab treatment. No other complications were noted.

Conclusions

Tofacitinib response is rapid and impressive in children suffering from ASC, and the safety profile appears comparable to or better than other available treatments. In the future, tofacitinib should be integrated into pediatric protocols.

Population pharmacokinetics and pharmacodynamics of efmarodocokin alfa (IL-22Fc)

Efmarodocokin alfa (IL-22Fc) is a fusion protein of human IL-22 linked to the crystallizable fragment (Fc) of human IgG4. It has been tested in multiple indications including inflammatory bowel disease (IBD). The purposes of the present analyses were to describe the population pharmacokinetics (PK) of efmarodocokin alfa and perform pharmacodynamic (PD) analysis on the longitudinal changes of the PD biomarker REG3A after efmarodocokin alfa treatment as well as identify covariates that affect efmarodocokin alfa PK and REG3A PD. The data used for this analysis included 182 subjects treated with efmarodocokin alfa in two clinical studies. The population PK and PD analyses were conducted sequentially. Efmarodocokin alfa concentration-time data were analyzed using a nonlinear mixed-effects modeling approach, and an indirect response model was adopted to describe the REG3A PD data with efmarodocokin alfa serum concentration linked to the increase in REG3A. The analysis software used were NONMEM and R. A 3-compartment model with linear elimination best described the PK of efmarodocokin alfa. The estimated population-typical value for clearance (CL) was 1.12 L/day, and volume of central compartment was 6.15 L. Efmarodocokin alfa CL increased with higher baseline body weight, C-reactive protein, and CL was 27.6% higher in IBD patients compared to healthy subjects. The indirect response PD model adequately described the longitudinal changes of REG3A after efmarodocokin alfa treatment. A popPK and PD model for efmarodocokin alfa and REG3A was developed and covariates affecting the PK and PD were identified.

Case report: Successful treatment of ulcerative colitis-related post-colectomy enteritis refractory to multiple therapies with ustekinumab

Ulcerative colitis-related severe post-colectomy enteritis is a rare condition. A few cases have undergone successful treatment with corticosteroids, Cyclosporine, Azathioprine, and Infliximab. We aim to evaluate the treatment outcome of ustekinumab in this rare case. Here we describe a 56-year-old woman with post-colectomy enteritis refractory to multiple therapies. Finally, the patient was administered with ustekinumab treatment. Under monitoring, the feces volume of the patient decreased from 5000-7000 mL per day to 1700-2000 mL. Over a one-year follow-up period, the patient gradually gained body weight, with the stoma drainage of formed brown stool. And the villi of the small intestinal mucosa restore growth. To our knowledge, this is the first report that indicates ustekinumab could be a treatment selection for ulcerative colitis-related severe post-colectomy enteritis.

Long-term outcomes of cyclosporin induction and ustekinumab maintenance combination therapy in patients with steroid-refractory acute severe ulcerative colitis

Background

Effective management of patients with acute severe ulcerative colitis (ASUC) is a major challenge and there remains a paucity of available maintenance treatment options after efficacious cyclosporin induction therapy.

Objectives

We investigated the long-term effectiveness and safety of cyclosporin and ustekinumab combination therapy in patients with steroid refractory ASUC.

Design

Monocentric, prospective study.

Methods

We included patients with steroid refractory ASUC with multiple failed prior advanced therapies, who were treated with cyclosporin and ustekinumab combination therapy.

Results

Among the 11 included patients, 10 had prior failure to infliximab and 8 failed at least three previous biological therapies. The mean baseline Mayo and Lichtiger scores were 10.9 (9-12) and 13.3 (11-14), respectively. Ustekinumab was initiated 3.2 weeks (1-8) after initiation of cyclosporin treatment and combination therapy was continued for a mean of 11.5 (4-20) weeks. Clinical response was achieved in six patients at week 16 and clinical steroid-free clinical remission in five patients at week 48. Endoscopic remission was achieved in five patients at week 16 and together with histological remission in five patients at week 52. Intestinal ultrasound demonstrated mean bowel wall thickening in the sigmoid colon of 5.5 mm at baseline and 3.5 mm at week 52, respectively. Two patients had to undergo colectomy (mean 4.5 months, range 3-6) and three stopped ustekinumab therapy due to ineffectiveness. Overall, combination therapy was well tolerated.

Conclusion

Combination of cyclosporin and ustekinumab therapy allowed nearly half of ASUC patients to reach clinical and endoscopic remission after 52 weeks, warranting further studies.

Trial registration

Not applicable.

Combining pharmacometric models with predictive and prognostic biomarkers for precision therapy in Crohn's disease: A case study of brazikumab

Pharmacometric models were used to investigate the utility of biomarkers in predicting the efficacy (Crohn's Disease Activity Index [CDAI]) of brazikumab and provide a data-driven framework for precision therapy for Crohn's disease (CD). In a phase IIa trial in patients with moderate to severe CD, treatment with brazikumab, an anti-interleukin 23 monoclonal antibody, was associated with clinical improvement. Brazikumab treatment effect was determined to be dependent on the baseline IL-22 (BIL22) or baseline C-reactive protein (BCRP; predictive biomarkers), and placebo effect was found to be correlated with the baseline CDAI (a prognostic biomarker). A maximal total inhibition on CDAI input function of 50.6% and 42.4% was predicted for patients with extremely high BIL22 or BCRP, compared to a maximal total inhibition of 20.9% and 17.8% for patients with extremely low BIL22 or BCRP, respectively, which were mainly due to the placebo effect. We demonstrated that model-derived baseline biomarker levels that achieve 50% of maximum unbound systemic concentration of 22.8 pg/mL and 8.03 mg/L for BIL22 and BCRP as the cutoffs to select subpopulations can effectively identify high-response subgroup patients with improved separation of responders when compared to using the median values as the cutoff. This work exemplifies the utility of pharmacometrics to quantify biomarker-driven responses in biologic therapies and distinguish between predictive and prognostic biomarkers, complementing clinical efforts of identifying subpopulations with higher likelihood of response to brazikumab.

Body Surface Area-Based Dosing of Infliximab is Superior to Standard Weight-Based Dosing in Children With Very Early Onset Inflammatory Bowel Disease

Background and Aims

Children with very early onset inflammatory bowel disease (VEO-IBD) are uniquely at risk of inadequate infliximab (IFX) exposure. We studied the association between standard body weight (BW)-based and body surface area (BSA)-based dosing strategies and outcomes.

Methods

We identified VEO-IBD patients treated with IFX before 9 years at a single center. Patients were separated into those that received a BSA-based dose (200 mg/m2) and standard BW dosing (5 mg/kg). IFX drug levels, dose intensification, time on steroids, and long-term outcomes were compared. Receiver operator characteristic curves determined the optimal BW- and BSA-based dose to achieve a trough ≥10 μg/ml at dose 4 (IFX#4).

Results

Forty-three children with VEO-IBD were identified. Receiver operator characteristic curves demonstrated optimal BW- and BSA-based doses to achieve IFX trough ≥10 μg/ml at IFX#4 were 7.5 mg/kg and 180mg/m2. Children were classified to standard BW dosing (22/43) and BSA dosing (10/43). IFX#4 trough was significantly higher in those who received BSA dosing (BSA 18.6 μg/ml [interquartile range 10.8-28.1] vs BW 5.1 μg/ml [interquartile range 2.6-10.7], P = .04). BSA dosing was more likely to achieve a target drug level >10 μg/ml at IFX#4 (BSA 70% vs BW 18%, P = .02). BW dosing was associated with a greater likelihood of dose escalation (BW 82% vs BSA 30%, P < .01) and a shorter time to first escalation. BSA dosing was associated with shorter time spent on steroids (P = .02).

Conclusion

Young children require higher IFX dosing to achieve adequate drug exposure. Our data support the use of a BSA-based dose of 200 mg/m2 or, if a BW-based approach is used, 7.5 mg/kg. BSA dosing allows the use of a consistent dose over the age and weight spectrum.

Efficacy of Switching to Adalimumab for Maintenance of Remission Following Induction Therapy with Tacrolimus in Patients with Ulcerative Colitis

BACKGROUND

Tacrolimus (TAC) effectively induces remission in refractory ulcerative colitis (UC). However, TAC therapy usually lasts for 3 months. Although azathioprine (AZA) is often used in maintenance therapy, the relapse rate remains high. Herein, we evaluated the efficacy of adalimumab (ADA) for remission maintenance in patients with UC after induction therapy with TAC.

METHODS

We prospectively enrolled patients with moderate-to-severe UC who achieved clinical remission after 3 months of TAC therapy with endoscopic non-mucosal healing (Cohort A). After TAC discontinuation, the remission maintenance rate up to 1 year after starting ADA therapy was examined. We retrospectively enrolled patients with UC treated with TAC (Cohort B). Among patients in clinical remission after TAC treatment for 3 months, those who received AZA as remission maintenance therapy after TAC discontinuation constituted the AZA group. Patients in Cohort A who received ADA and AZA as remission maintenance therapy after TAC discontinuation constituted the ADA + AZA group. We compared the remission maintenance rates in the AZA and ADA + AZA groups for up to 5 years after TAC discontinuation.

RESULTS

In Cohort A, of the 46 patients with UC treated with TAC, 17 were eligible for analysis after receiving ADA as remission maintenance therapy. A notable 88.2% (15/17) were still in remission 1 year after starting ADA. The ADA + AZA group (n = 16) exhibited a significantly higher relapse-free rate than the AZA group (n = 26) (p < 0.05; log-rank test).

CONCLUSION

switching to ADA for remission maintenance in patients with refractory UC who achieved clinical remission with TAC is clinically useful.

Mirikizumab for the treatment of moderate to severe ulcerative colitis

Despite a growing number of available therapeutic options for ulcerative colitis (UC), up to 50% of patients do not respond to initial treatment or lose response over time, highlighting the need for novel therapies. The IL-23 pathway has emerged as an important therapeutic target for UC. Mirikizumab is a humanized IgG4 monoclonal antibody against the p19 subunit of IL-23, dosed intravenously during induction and subcutaneously during maintenance. It is effective for the induction and maintenance of remission in moderately to severely active UC, including patients with prior failure of biological or tofacitinib therapy. Like other IL-23 antagonists, mirikizumab has a favorable safety profile. It is the first agent of its class to receive regulatory approval for moderately to severely active UC in Europe.

Infliximab Induction Strategies in Corticosteroid-Refractory Acute Severe Ulcerative Colitis: A Case Series and Literature Review

Acute severe ulcerative colitis (ASUC) is an emergent medical condition and particularly challenging to treat efficaciously. Infliximab is one of the medical salvage treatment options after corticosteroid refractoriness, but the best induction strategy is not yet defined. With this case series, the authors intend to describe three corticosteroid-refractory ASUC cases with different intensified/accelerated infliximab induction approaches and review the literature on this topic. The first case describes an 18-year-old girl with ASUC at disease onset with rapid progression to toxic megacolon, complicated also with anemia, hypoalbuminemia, and coagulopathy. After corticosteroid failure, both accelerated and intensified (10 mg/kg) infliximab regimen was completed within 11 days, with solid clinical response and colon imaging normalization. Second, we present a 26-year-old male with left-sided ulcerative colitis known for 2 years, under mesalazine, who developed a moderate flare and was started on infliximab after partial and inconsistent response to corticosteroids. During the induction period, he presented this time an ASUC episode, which motivated an early and intensified third dose with good clinical response. Finally, we describe the case of a 78-year-old man with ulcerative proctitis for 12 years presenting ASUC with proximal disease extension as well. After unsatisfactory response to corticosteroids, infliximab was initiated on an accelerated induction regimen, completed in 13 days, with the standard dose, achieving clinical remission. Accelerated or intensified infliximab induction plans are becoming current clinical practice in corticosteroid-refractory ASUC. Current guidelines refer to the possibility of this type of strategies, not determining the optimal regimen due to lack of solid evidence. Literature is mainly based on retrospective studies, not randomized, with heterogeneous groups according to disease severity, and the effect on colectomy rates, mainly on the long term, is not clear. Additional well-supported studies are needed on this subject in order to seek a more widely uniform approach.

Review article: Updated management of acute severe ulcerative colitis: From steroids to novel medical strategies

Acute severe ulcerative colitis (ASUC) occurs in up to 25% of patients with ulcerative colitis (UC). Therapeutic approaches have evolved during the past years with the increasing bio exposure of admitted patients and the extension of the number of approved drugs for UC. In this review, we aimed to summarize the latest evidence in short-term and long-term medical strategies for ASUC. In addition to general principles such as venous thromboembolism prophylaxis, screening for triggering and worsening factors and close monitoring, first-line therapy for ASUC remains intravenous corticosteroids. In naive patients, the optimum maintenance strategy for steroid-responding patients does not necessarily include biologics. Second-line therapy includes infliximab or calcineurin inhibitors (CNIs) with similar short- and long-term colectomy rates. Despite its pathophysiological relevance, there is insufficient evidence to promote intensified induction with infliximab. Prior treatment exposure is a cornerstone for guiding therapeutic choice of short- and long-term therapies in the context of ASUC: in anti-TNF exposed patients, CNIs may be favored as a bridge therapy to vedolizumab or ustekinumab. Third-line salvage therapy could be a therapeutic option in selected patients referred to expert centers. Additionally, evidence is accumulating regarding the use of tofacitinib in ASUC.

Comparison of Clinical Outcomes in Pediatric Patients with Ileocolonic Crohn Disease Treated with Infliximab Versus Adalimumab

OBJECTIVES

Infliximab is considered superior to adalimumab in patients with ulcerative colitis, especially in severe cases. Whether this is true for Crohn disease (CD) patients with colonic involvement is unclear. Our aim was to compare the clinical effectiveness of infliximab versus adalimumab in pediatric ileocolonic (L3) CD.

METHODS

This retrospective study included patients <18 years with ileocolonic CD treated with infliximab or adalimumab between 2014 and 2021. Primary outcome was steroid-free clinical remission by week 52. Secondary outcomes were treatment modifications, drug discontinuation, inflammatory bowel disease (IBD)-associated hospitalizations, and surgery during the first year of treatment.

RESULTS

We identified 74 patients treated with adalimumab and 41 with infliximab, with comparable demographic features. Concomitant immunomodulator therapy at biologic initiation was significantly lower in the adalimumab group (28% vs 85%, P < 0.001). Rates of drug intensification were higher in the infliximab group at end of induction (EOI) and at 52 weeks (55% vs 32% and 88% vs 46%, P < 0.001). Given significant differences between initial median Pediatric Crohn Disease Activity Index scores (20.0 [interquartile range, IQR 15.0-27.5] vs 11.0 [IQR 7.5-20.0] for infliximab and adalimumab groups, respectively, P < 0.001), propensity score matching was performed. Following matching, the rate of patients in steroid-free clinical remission by EOI was significantly higher in the adalimumab group (93.8% vs 46.9%, P < 0.001), but comparable by 1 year. Moreover, inflammatory markers and fecal calprotectin values were also similar at these time points. Rates of drug discontinuation, IBD-associated admissions, and surgery were similar between groups.

CONCLUSIONS

In a retrospective study of patients with ileocolonic CD, adalimumab and infliximab had comparable outcomes by 52 weeks.

Dose escalation randomised study of efmarodocokin alfa in healthy volunteers and patients with ulcerative colitis

BACKGROUND

The interleukin-22 cytokine (IL-22) has demonstrated efficacy in preclinical colitis models with non-immunosuppressive mechanism of action. Efmarodocokin alfa (UTTR1147A) is a fusion protein agonist that links IL-22 to the crystallisable fragment (Fc) of human IgG4 for improved pharmacokinetic characteristics, but with a mutation to minimise Fc effector functions.

METHODS

This randomised, phase 1b study evaluated the safety, tolerability, pharmacokinetics and pharmacodynamics of repeat intravenous dosing of efmarodocokin alfa in healthy volunteers (HVs; n=32) and patients with ulcerative colitis (n=24) at 30-90 µg/kg doses given once every 2 weeks or monthly (every 4 weeks) for 12 weeks (6:2 active:placebo per cohort).

RESULTS

The most common adverse events (AEs) were on-target, reversible, dermatological effects (dry skin, erythema and pruritus). Dose-limiting non-serious dermatological AEs (severe dry skin, erythema, exfoliation and discomfort) were seen at 90 μg/kg once every 2 weeks (HVs, n=2; patients, n=1). Pharmacokinetics were generally dose-proportional across the dose levels, but patients demonstrated lower drug exposures relative to HVs at the same dose. IL-22 serum biomarkers and IL-22-responsive genes in colon biopsies were induced with active treatment, and microbiota composition changed consistent with a reversal in baseline dysbiosis. As a phase 1b study, efficacy endpoints were exploratory only. Clinical response was observed in 7/18 active-treated and 1/6 placebo-treated patients; clinical remission was observed in 5/18 active-treated and 0/6 placebo-treated patients.

CONCLUSION

Efmarodocokin alfa had an adequate safety and pharmacokinetic profile in HVs and patients. Biomarker data confirmed IL-22R pathway activation in the colonic epithelium. Results support further investigation of this non-immunosuppressive potential inflammatory bowel disease therapeutic.

TRIAL REGISTRATION NUMBER

NCT02749630.

In-hospital management of inflammatory bowel disease

PURPOSE OF REVIEW

The management of hospitalized patients with inflammatory bowel disease (IBD) is complex. Despite considerable therapeutic advancements in outpatient ulcerative colitis and Crohn's disease management, the in-hospital management continues to lag with suboptimal outcomes. The purpose of this review is to provide a brief overview of our approach to managing patients hospitalized with acute severe ulcerative colitis (ASUC) and Crohn's disease-related complications, followed by a summary of emerging evidence for new management approaches.

RECENT FINDINGS

ASUC has seen the emergence of well validated prognostic models for colectomy as well as the development of novel treatment strategies such as accelerated infliximab dosing, Janus kinase inhibitor therapy, and sequential therapy, yet the rate of colectomy for steroid-refractory ASUC has not meaningfully improved. Crohn's disease has seen the development of better diagnostic tools, early Crohn's disease-related complication stratification and identification, as well as better surgical techniques, yet the rates of hospitalization and development of Crohn's disease-related complications remain high.

SUMMARY

Significant progress has been made in the in-hospital IBD management; however, both the management of ASUC and hospitalized Crohn's disease remain a challenge with suboptimal outcomes. Critical knowledge gaps still exist, and dedicated studies in hospitalized patients with IBD are needed to address them.

Comparison of the Pharmacokinetics of CT-P13 Between Crohn's Disease and Ulcerative Colitis

BACKGROUND

We aimed to compare trough infliximab levels and the development of antidrug antibody (ADA) for 1 year between Crohn's disease (CD) and ulcerative colitis (UC) patients who were biologic-naive, and to evaluate their impact on clinical outcomes.

METHODS

This was a prospective, multicenter, observational study. Biologic-naive patients with moderate to severe CD or UC who started CT-P13, an infliximab biosimilar, therapy were enrolled. Trough drug and ADA levels were measured periodically for 1 year after CT-P13 initiation.

RESULTS

A total of 267 patients who received CT-P13 treatment were included (CD 168, UC 99). The rates of clinical remission (72% vs. 32.3%, P <0.001) at week 54 were significantly higher in CD than in UC. The median trough drug level (μg/mL) was significantly higher in CD than in UC up to week 14 (week 2, 18.7 vs. 14.7, P <0.001; week 6, 12.5 vs. 8.6, P <0.001; week 14, 3.4 vs. 2.5, P =0.001). The median ADA level (AU/mL) was significantly lower in CD than in UC at week 2 (6.3 vs. 6.5, P =0.046), week 30 (7.9 vs. 11.8, P =0.007), and week 54 (9.3 vs. 12.3, P =0.032). Development of ADA at week 2 [adjusted odds ratio (aOR)=0.15, P =0.026], initial C-reactive protein level (aOR=0.87, P =0.032), and CD over UC (aOR=1.92, P <0.001) were independent predictors of clinical remission at week 54.

CONCLUSION

Infliximab shows more favorable pharmacokinetics, including high drug trough and low ADA levels, in CD than in UC, which might result in better clinical outcomes for 1-year infliximab treatment in CD patients.

The Role of Low-Dose Oral Methotrexate in Increasing Anti-TNF Drug Levels and Reducing Immunogenicity in IBD

Concomitant immunomodulation is utilised in combination with anti-TNF therapy for IBD primarily to increase drug levels and prevent anti-drug antibody formation. Whilst thiopurines have traditionally been the immunomodulator of choice in IBD populations, there are concerns regarding the long-term safety of the prolonged use of these agents: particularly an association with lymphoproliferative disorders. Given this, we have explored the existing literature on the use of low-dose oral methotrexate as an alternative immunomodulator for this indication. Although there is a lack of data directly comparing the efficacies of methotrexate and thiopurines as concomitant immunomodulators, the available literature supports the use of methotrexate in improving the pharmacokinetics of anti-TNF agents. Furthermore, low-dose oral methotrexate regimens appear to have comparable efficacies to higher-dose parenteral administration and are better tolerated. We suggest that clinicians should consider the use of low-dose oral methotrexate as an alternative to thiopurines when the primary purpose of concomitant immunomodulation is to improve anti-TNF pharmacokinetics.

Surface plasmon resonance assays for the therapeutic drug monitoring of infliximab indicate clinical relevance of anti-infliximab antibody binding properties

OBJECTIVES

The therapeutic antibody infliximab (IFX) has improved the life quality of numerous autoinflammatory disease patients. However, IFX can trigger the generation of anti-drug antibodies (ADA), whose optimal evaluation and management are currently subject of controversial discussions. We present two novel surface plasmon resonance (SPR) biosensor assays for therapeutic drug monitoring of IFX and characterization of ADA and investigated the diagnostic value of ADA binding properties.

METHODS

IFX and ADA were quantified via developed SPR biosensor assays (IFXmon and ADAmon, respectively) and diagnostics-approved ELISA in sera from inflammatory bowel disease patients. Pre-analytic ADA enrichment with magnetic beads enabled analytical drug tolerance of the ADAmon assay. The dissociation ratio (DissR) as an index for ADA:IFX binding stability was calculated from the SPR sensorgrams of ADA quantification runs.

RESULTS

IFX levels determined by IFXmon assay and ELISA showed high agreement, whereas ADA quantification concordance between ADAmon assay and ELISA was poor. In patients, DissR was predominantly constant over time and differed significantly between therapy outcomes. A DissR cut-off of 1.524 indicated undetectable IFX levels with 71.4% sensitivity and 88.9% specificity. Additionally, the SPR reference surface was exploited as serum-individual negative control to check result plausibility within multi-sample run sequences.

CONCLUSIONS

Overall, both SPR biosensor assays exhibited reliable quantitative performance with accuracies superior to their ELISA counterparts and precision inferior to ELISA only for ADAmon. DissR presented itself as promising ADA binding parameter and could contribute to both earlier and more tailored therapeutic decisions.

Efficacy of Early Optimization of Infliximab Guided by Therapeutic Drug Monitoring during Induction-A Prospective Trial

Therapeutic drug monitoring (TDM) during induction therapy with anti-tumor necrosis factor drugs has emerged as a strategy to optimize response to these biologics and avoid undesired outcomes related to inadequate drug exposure. This study aimed to describe clinical, biological, and endoscopic remission rates at six months in Brazilian inflammatory bowel disease (IBD) patients following a proactive TDM algorithm guided by IFX trough levels (ITL) and antibodies to IFX (ATI) levels during induction, at week six. A total of 111 IBD patients were prospectively enrolled, excluding those previously exposed to the drug. ITL ≥ 10 μg/mL was considered optimal. Patients with suboptimal ITL (<10 µg/mL) were guided according to ATI levels. Those who presented ATI ≤ 200 ng/mL underwent dose intensification in the maintenance phase, and patients with ATI > 200 ng/mL discontinued IFX. In our study, proactive TDM was associated with persistence in the IFX rate at six months of 82.9%. At that time, rates of clinical, biological, and endoscopic remission in patients under IFX treatment were 80.2%, 73.9%, and 48.1%, respectively. Applying a simplified TDM-guided algorithm during induction seems feasible and can help improve patients' outcomes in clinical practice.

Protective effect of the novel calcineurin inhibitor voclosporin in experimental colitis

Background and aims

Acute severe steroid-refractory ulcerative colitis remains a medically challenging condition with frequent need of surgery. It can be treated with the calcineurin inhibitor cyclosporine A with the need for therapeutic drug monitoring and significant toxicity. Recently, a novel calcineurin inhibitor, voclosporin, has been approved for the treatment of lupus nephritis with no need for therapeutic drug monitoring and an improved long-term safety profile. However, the therapeutic effect of voclosporin in acute severe steroid-refractory ulcerative colitis is still uncertain. We aimed to assess the therapeutic potential of voclosporin to ameliorate inflammation in an experimental model of colitis.

Methods

We used the dextran sodium sulfate-induced model of colitis in C57BL/6 J wildtype mice treated with either cyclosporine A, voclosporin or solvent control. We employed endoscopy, histochemistry, immunofluorescence, bead-based multiplex immunoassays and flow cytometry to study the therapeutic effect of calcineurin inhibitors in a preventive setting.

Results

Acute colitis was induced by dextran sodium sulfate characterized by weight loss, diarrhea, mucosal erosions and rectal bleeding. Both cyclosporine A and voclosporin strongly ameliorated the course of disease and reduced colitis severity in a similar manner.

Conclusion

Voclosporin was identified as biologically effective in a preclinical model of colitis and may be a potential therapeutic option in treating acute severe steroid-refractory ulcerative colitis.

Therapeutic Drug Monitoring of Infliximab in Acute Severe Ulcerative Colitis

Therapeutic drug monitoring (TDM) is a useful strategy in ulcerative colitis (UC). Nearly a quarter of UC patients will experience acute severe UC (ASUC) in their lifetime, including 30% who will fail first-line corticosteroid therapy. Steroid-refractory ASUC patients require salvage therapy with infliximab, cyclosporine, or colectomy. Fewer data are available for the use of TDM of infliximab in ASUC. The pharmacokinetics of ASUC make TDM in this population more complex. High inflammatory burden is associated with increased infliximab clearance, which is associated with lower infliximab drug concentrations. Observational data support the association between increased serum infliximab concentrations, lower clearance, and favorable clinical and endoscopic outcomes, as well as decreased rates of colectomy. Data regarding the benefit of accelerated or intensified dosing strategies of infliximab-as well as target drug concentration thresholds-in ASUC patients remain more equivocal, though limited by their observational nature. Studies are underway to further evaluate optimal dosing and TDM targets in this population. This review examines the evidence for TDM in patients with ASUC, with a focus on infliximab.

Current Role of Monoclonal Antibody Therapy in Pediatric IBD: A Special Focus on Therapeutic Drug Monitoring and Treat-to-Target Strategies

In the last two decades, biologicals have become essential in treating children and adolescents with inflammatory bowel disease. TNF-α inhibitors (infliximab, adalimumab and golimumab) are preferentially used. Recent studies suggest that early application of TNF-α inhibitors is beneficial to inducing disease remission and preventing complications such as development of penetrating ulcers and fistulas. However, treatment failure occurs in about one third of pediatric patients. Particularly, children and adolescents differ in drug clearance, emphasizing the importance of pharmacokinetic drug monitoring in the pediatric setting. Here, current data on the choice and effectiveness of biologicals and therapeutic drug monitoring strategies are reviewed.

Real world population pharmacokinetic study in children and young adults with inflammatory bowel disease discovers novel blood and stool microbial predictors of vedolizumab clearance

BACKGROUND

Vedolizumab for inflammatory bowel disease (IBD) is often intensified based on distinct pharmacokinetics in children. Prior adult-specific population pharmacokinetic models have identified limited covariates of drug clearance.

AIMS

To establish a population pharmacokinetic model for children and young adults to identify novel covariates of drug clearance to better account for paediatric-specific inter-patient variability in vedolizumab pharmacokinetics; a key secondary exploratory aim was to identify microbial signatures of pharmacokinetic outcomes in a subset of patients.

METHODS

The study included data from 463 observed vedolizumab concentrations (59 peaks and 404 troughs) from 74 patients with IBD (52 with Crohn's disease and 22 with ulcerative colitis or unclassified IBD, median age 16 years). Pharmacokinetic analysis was conducted with non-linear mixed effects modelling. For the evaluation of the exposure-response relationship, clinical outcomes were evaluated by trough levels, clearance and vedolizumab exposure. Whole-genome metagenomic sequencing was conducted at baseline and week 2.

RESULTS

A two-compartment population pharmacokinetic model was identified with a clear correlation between CL and weight, erythrocyte sedimentation rate, and hypoalbuminemia. Trough concentrations before infusion 3 (37 μg/ml) and before infusion 4 (20 μg/ml) best predicted steroid-free clinical remission at infusion 4. Using faecal metagenomics, we identified an early (baseline and week 2) abundance of butyrate-producing species and pathways that were associated with an infusion 4 trough concentration >20 μg/ml.

CONCLUSIONS

This novel paediatric vedolizumab pharmacokinetic model could inform precision dosing. While additional studies are needed, an abundance of faecal butyrate producers is associated with early response to vedolizumab, suggesting that microbial analysis may be beneficial to biological selection.

Acute Severe Ulcerative Colitis: Optimal Strategies for Drug Therapy

Acute severe ulcerative colitis (ASUC) is a life-threatening medical emergency with considerable morbidity (30% to 40%). Patients with ASUC require hospitalization for prompt medical treatment, and colectomy is considered if medical therapy fails. Corticosteroids remain the primary initial therapy, although one-third of patients do not respond to treatment. Clinical data have indicated that cyclosporine, tacrolimus, and infliximab can be used to treat patients with ASUC who do not respond to intravenous corticosteroids. The effectiveness and safety of sequential therapy have recently been reported; however, the data are not convincing. Importantly, timely decision-making with rescue therapy or surgical treatment is critical to manage ASUC without compromising the health or safety of the patients. In addition, risk stratification and the use of predictive clinical parameters have improved the clinical outcome.of ASUC. Multidisciplinary teams that include inflammatory bowel disease experts, colorectal surgeons, and other medical staff contribute to the better management of patients with ASUC. In this review, we introduce current evidence and present a clinical approach to manage ASUC.

Pharmacokinetics of biologics in gastric cancer

Gastric cancer (GC) remains one of the leading causes of cancer death worldwide despite improvements in therapeutic options. Several biologics have been investigated in patients with GC, including those approved in other solid tumors; however, the success rate of the pivotal trials that investigated these biologic molecules in GC remains low. Elevation in total clearance and a decrease in systemic pharmacokinetic (PK) exposure in GC compared with other indications have been observed in these biologics across different pathways. Achieving optimal exposure for patients with GC is an important factor in balancing risk and optimizing therapeutic benefit and thus maximizing chance of positive outcomes for pivotal trials. Therefore, in this review, we summarize the PK disposition of several molecules (e.g., anti-HER2, anti-VEGF, and anti-PD1) evaluated in GC and showed a consistent trend of lower drug exposure as compared to other solid tumors. We hypothesize that two possible mechanisms: (1) hyper-catabolism of endogenous and exogenous proteins due to cancer cachexia; and (2) gastric protein leakage due to local inflammation at the gastrointestinal tract may explain or partially explain the increase of clearance in patients with GC. Last, the potential implications of such findings on dose selection to optimize the benefit: risk profile for biologics in GC are also discussed.

Precision medicine and drug optimization in adult inflammatory bowel disease patients

Inflammatory bowel diseases (IBD) encompass two main entities including ulcerative colitis and Crohn's disease. Although having a common global pathophysiological mechanism, IBD patients are characterized by a significant interindividual heterogeneity and may differ by their disease type, disease locations, disease behaviours, disease manifestations, disease course as well as treatment needs. Indeed, although the therapeutic armamentarium for these diseases has expanded rapidly in recent years, a proportion of patients remains with a suboptimal response to medical treatment due to primary non-response, secondary loss of response or intolerance to currently available drugs. Identifying, prior to treatment initiation, which patients are likely to respond to a specific drug would improve the disease management, avoid unnecessary side effects and reduce the healthcare expenses. Precision medicine classifies individuals into subpopulations according to clinical and molecular characteristics with the objective to tailor preventative and therapeutic interventions to the characteristics of each patient. Interventions would thus be performed only on those who will benefit, sparing side effects and expense for those who will not. This review aims to summarize clinical factors, biomarkers (genetic, transcriptomic, proteomic, metabolic, radiomic or from the microbiota) and tools that could predict disease progression to guide towards a step-up or top-down strategy. Predictive factors of response or non-response to treatment will then be reviewed, followed by a discussion about the optimal dose of drug required for patients. The time at which these treatments should be administered (or rather can be stopped in case of a deep remission or in the aftermath of a surgery) will also be addressed. IBD remain biologically complex, with multifactorial etiopathology, clinical heterogeneity as well as temporal and therapeutic variabilities, which makes precision medicine especially challenging in this area. Although applied for many years in oncology, it remains an unmet medical need in IBD.