Baseline Clearance of Infliximab Is Associated With Requirement for Colectomy in Patients With Acute Severe Ulcerative Colitis

Factors Associated With Response to Rescue Therapy in Acute Severe Ulcerative Colitis

BACKGROUND

Acute severe ulcerative colitis (ASUC) is a medical emergency for which colectomy is required in patients who do not respond to rescue therapy. While previous studies have predominantly focused on predicting outcome to first-line corticosteroid therapy, there is a need to understand the factors associated with response to rescue therapies in order to improve clinical outcomes. We reviewed the evidence regarding factors associated with response to rescue therapy in adults with ASUC and identified future directions for research.

METHODS

A systematic search of the literature was conducted, and 2 reviewers independently assessed studies for inclusion.

RESULTS

Of 3509 records screened, 101 completed studies were eligible for inclusion. We identified 42 clinical, hematological, biochemical, endoscopic, or pharmacological factors associated with response to rescue therapy. Older age (≥50 years), thiopurine experience, and cytomegalovirus or Clostridioides difficile infection were associated with a higher risk of nonresponse to rescue therapy. Biochemical factors associated with poorer response included an elevated C-reactive protein (CRP) ≥30mg/L on admission, hypoalbuminemia and an elevated ratio of CRP to albumin. Severe endoscopic findings, including a Mayo endoscopic score of 3 or Ulcerative Colitis Endoscopic Index of Severity ≥5, portended poorer outcomes. The role of fecal calprotectin and therapeutic value of measuring infliximab drug levels in ASUC remain to be defined.

CONCLUSIONS

Response to rescue therapy can be predicted by several specific factors, which would aid clinical decision-making. Existing and emerging factors should be integrated within predictive and prognostic models to help improve clinical outcomes.

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.

Colombian experience with the use of tofacitinib in severe acute ulcerative colitis: A case series study

INTRODUCTION

Tofacitinib is indicated in patients with moderate to severe ulcerative colitis (UC); however, given its rapid onset of action, it may constitute an alternative in patients with hospitalized severe acute UC. There are few data on this indication in the literature. The aim of this study was to describe the efficacy and safety of tofacitinib in the management of patients with hospitalized UC, as well as its clinical characteristics and other treatment patterns.

MATERIALS AND METHODS

Descriptive observational study of adults and children with CUAG treated with tofacitinib between June 2019 and December 2022 in Colombia. Sociodemographic and clinical variables were collected, therapeutic response was evaluated in different periods of time and descriptive analysis of quantitative and qualitative variables was performed.

RESULTS

Six patients (five adults and one pediatric), mean age 33.2 (SD: 8.5) years, with CUAG. Symptom remission was obtained in 100% of patients at day 7 after tofacitinib initiation. In three patients information was obtained beyond 6 months, with 100% clinical, biochemical, and endoscopic remission and without requiring colectomy. In the case of the pediatric patient, symptom remission was achieved one week after starting tofacitinib, remaining in clinical, biochemical and endoscopic remission beyond 6 months. No serious adverse events were reported in any of the cases.

CONCLUSIONS

Tofacitinib represents a rescue therapeutic alternative in CUAG, with rapid clinical response, adequate tolerance and less need for colectomy, being sustained for periods beyond 6 months.

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.

Acute severe ulcerative colitis management: unanswered questions and latest insights

Acute severe ulcerative colitis (ASUC) is a distinctive ulcerative colitis flare presentation characterised by the presence of systemic inflammation as well as bloody diarrhoea, and occurs at least once in 25% of patients with ulcerative colitis during their disease course. Each episode carries a risk of complications, need for colectomy, and mortality. Little is known about ASUC pathogenesis, although impaired host-microbiota crosstalk involving pathobionts is suspected. In this Review, we discuss unanswered questions and results from the latest research on the medical-first-line, second-line, and potential third-line therapies-and surgical management of ASUC. We detail promising options for management, such as the use of enteral nutrition in combination with intravenous steroids, the ability to predict early failure of first-line or second-line therapies, and the emerging role of JAK inhibitors. An optimal framework to personalise therapy on the basis of multiomics tools is yet to be developed.

Outcomes Following Acute Severe Colitis at Initial Presentation: A Multi-centre, Prospective, Paediatric Cohort Study

AIM

To assess contemporary outcomes in children with acute severe ulcerative colitis [ASUC] at initial presentation.

METHODS

Between April 2014 and January 2019, children aged <17 years, with new onset ASUC (Paediatric Ulcerative Colitis Activity Index [PUCAI ≥65) were prospectively followed in a Canadian inception cohort study. 16S rRNA amplicon sequencing captured microbial composition of baseline faecal samples. Primary endpoint was corticosteroid-free clinical remission with intact colon at 1 year [PUCAI <10, no steroids ≥4 weeks].

RESULTS

Of 379 children with new onset UC/IBD-unclassified, 105 [28%] presented with ASUC (42% male; median [interquartile range; [IQR]) age 14 [11-16] years; extensive colitis in all). Compared with mild UC, gut microbiome of ASUC patients had lower α-diversity, decreased beneficial anaerobes, and increased aerobes; 54 [51%] children were steroid-refractory and given infliximab [87% intensified regimen]. Corticosteroid-free remission at 1 year was achieved by 62 [61%] ASUC cohort (by 34 [63%] steroid-refractory patients, all on biologics; by 28 [55%] steroid responders,13 [25%] on 5- aminosalicylic acid [5-ASA], 5 [10%] on thiopurines, 10 [20%] on biologics). By 1 year, 78 [74%] escalated to infliximab including 24 [47%] steroid-responders failed by 5-ASA and/or thiopurines. In multivariable analysis, clinical predictors for commencing infliximab included hypoalbuminaemia, greater PUCAI, higher age, and male sex. Over 18 months, repeat corticosteroid course[s] and repeat hospitalisation were less likely among steroid-refractory versus -responsive but -dependent patients (adjusted odds ratio [aOR] 0.71 [95% CI 0.57-0.89] and 0.54 [95% CI 0.45-0.66], respectively).

CONCLUSION

The majority of children presenting with ASUC escalate therapy to biologics. Predictors of need for advanced therapy may guide selection of optimal maintenance therapy.

Poor prognostic factors of pharmacokinetic origin predict outcomes in inflammatory bowel disease patients treated with anti-tumor necrosis factor-α

Introduction

We evaluated baseline Clearance of anti-tumor necrosis factors and human leukocyte antigen variant (HLA DQA1*05) in combination as poor prognostic factors (PPF) of pharmacokinetic (PK) origin impacting immune response (formation of antidrug antibodies) and disease control of inflammatory bowel disease (IBD) patients treated with infliximab or adalimumab.

Methods

Baseline Clearance was estimated in IBD patients before starting treatment using weight and serum albumin concentrations. HLA DQA1*05 carrier status (rs2097432 A/G or G/G variant) was measured using real time polymerase chain reaction. The outcomes consisted of immune response, clinical and biochemical remission (C-reactive protein<3 mg/L in the absence of symptoms), and endoscopic remission (SES-CD<3). Statistical analysis consisted of logistic regression and nonlinear mixed effect models.

Results and discussion

In 415 patients enrolled from 4 different cohorts (median age 27 [IQR: 15-43] years, 46% females), Clearance>0.326 L/day and HLA DQA1*05 carrier status were 2-fold more likely to have antidrug antibodies (OR=2.3, 95%CI: 1.7-3.4; p<0.001, and OR=1.9, 95%CI: 1.4-2.8; p<0.001, respectively). Overall, each incremental PPF of PK origin resulted in a 2-fold (OR=2.16, 95%CI: 1.7-2.7; p<0.11) [corrected] higher likelihood of antidrug antibody formation. The presence of both PPF of PK origin resulted in higher rates of antidrug antibodies (p<0.01) and lower clinical and biochemical remission (p<0.01). Each incremental increase in PPF of PK origin associated with lower likelihood of endoscopic remission (OR=0.4, 95%CI: 0.2-0.7; p<0.001). Prior biologic experience heightened the negative impact of PPF of PK origin on clinical and biochemical remission (p<0.01). Implementation of proactive therapeutic drug monitoring reduced it, particularly during maintenance and in the presence of higher drug concentrations (p<0.001). We conclude that PPF of PK origin, including both higher Clearance and carriage of HLA DQA1*05, impact outcomes in patients with IBD.

Drug Clearance in Patients with Inflammatory Bowel Disease Treated with Biologics

Biological therapy is very effective for treating patients with moderate to severe inflammatory bowel disease (IBD). However, up to 40% can have primary non-response, and up to 50% of the patients can experience a loss of response to anti-tumor necrosis factor therapy. These undesirable outcomes can be attributed to either a mechanistic failure or pharmacokinetic (PK) issues characterized by an inadequate drug exposure and a high drug clearance. There are several factors associated with accelerated clearance of biologics including increased body weight, low serum albumin and immunogenicity. Drug clearance has gained a lot of attention recently as cumulative data suggest that there is an association between drug clearance and therapeutic outcomes in patients with IBD. Moreover, clearance is used by model informed precision dosing (MIDP) tools, or PK dashboards, to adjust the dosing for reaching a target drug concentration threshold towards a more personalized application of TDM. However, the role of drug clearance in clinical practice is yet to be determined. This comprehensive review aims to present data regarding the variables affecting the clearance of specific biologics, the association of clearance with therapeutic outcomes and the role of clearance monitoring and MIPD in patients with IBD.

The current role of Tofacitinib in acute severe ulcerative colitis in adult patients: A systematic review

BACKGROUND

Despite rescue therapy, acute severe ulcerative colitis (ASUC) is associated with a high risk of colectomy, while treatment options remain limited. Tofacitinib, a rapidly acting Janus Kinase (JAK) inhibitor, is gaining ground as an effective alternative treatment option for the management of acute severe ulcerative colitis, which may prevent emergency colectomy.

METHODS

A systematic literature search of PubMed and Embase was undertaken for studies of adult patients with ASUC treated with tofacitinib.

RESULTS

In total, two observational studies, seven case series and five case reports incorporating 134 patients who received tofacitinib in ASUC were identified with a follow-up period ranging from 30 days to 14 months. Overall, the pooled colectomy rate was 23.9% (95% CI 16.6-31.2). The pooled 90-day and 6-month colectomy free rate were 79.9% (95% CI 73.1-86.7) and 71.6% (95% CI 64-79.2) respectively. The most frequent adverse event was C. Difficile infection.

CONCLUSIONS

Tofacitinib appears to be a promising option for the treatment of ASUC. Randomized clinical trials are required to further access the efficacy, safety and optimal dose of tofacitinib in cases of ASUC.

The Combination of Predictive Factors of Pharmacokinetic Origin Associates with Enhanced Disease Control during Treatment of Pediatric Crohn's Disease with Infliximab

Infliximab (IFX) concentrations are a predictive factor (PF) of pharmacokinetic (PK) origin in the treatment of Crohn's disease (CD). We evaluated Clearance, another PF of PK origin, either alone or in combination with concentrations. They were evaluated from two cohorts, the first designed to receive standard dosing (n = 37), and the second designed to proactively target therapeutic IFX concentrations (n = 108). Concentrations were measured using homogeneous mobility shift assay. Clearance was estimated using the nonlinear mixed effects methods with Bayesian priors. C-reactive protein-based clinical remission (<3 mg/L in the absence of symptoms) was used for the disease control outcome measure. Longitudinal changes in disease control due to factors including time, IFX concentration, and Clearance were analyzed using repeated event analysis. Change in objective function value (∆OFV) was calculated to compare concentration and Clearance. The results indicated that lower baseline Clearance and proactive dosing associated with enhanced disease control during induction (p < 0.01). Higher IFX concentrations and lower Clearance measured at the second, third, and fourth infusion yielded improved disease control during maintenance (p < 0.032). During maintenance, the association with disease control was better with Clearance than with concentrations (∆OFV = -19.2; p < 0.001), and the combination of both further minimized OFV (p < 0.001) with markedly improved clinical yield in the presence of both PF of PK origin. We conclude that the combination of IFX concentration and Clearance are better predictors of therapeutic outcome compared with either one alone.

Efficacy and Safety of Tacrolimus or Infliximab Therapy in Children and Young Adults With Acute Severe Colitis

INTRODUCTION

One-third of children and young adults admitted for management of acute severe colitis (ASC) fail intravenous corticosteroids. Infliximab (IFX) or tacrolimus (TAC) is often used to prevent urgent colectomy in these patients. However, no prior studies have reviewed the outcome of pediatric patients with ASC who were treated with either IFX or TAC.

METHODS

We retrospectively identified 170 pediatric patients with ASC admitted to our institution who did not respond to intravenous corticosteroids and were subsequently treated with either IFX or TAC. We compared 6-month colectomy rates, time to colectomy, improvement in disease activity indices, and adverse effects.

RESULTS

The mean age of patients in the IFX (n = 84) and TAC (n = 86) groups were 14 and 13.8 years, respectively. The median study follow-up time was 23 months. The rate of colectomy 6 months from rescue therapy was similar whether patients received IFX or TAC (22.6% vs 26.7%, respectively, P = 0.53). The mean decline in Pediatric Ulcerative Colitis Activity Index scores from admission to discharge in those treated with IFX (31.9) or TAC (29.8) was similar (P = 0.63). Three patients treated with IFX experienced infusion reactions. Six patients treated with TAC experienced changes in renal function or electrolytes, and 4 patients reported neurologic symptoms.

CONCLUSIONS

There were no significant differences in the likelihood of colectomy 6 months after initiating IFX or TAC rescue therapy. Efficacy of both agents was comparable. The types of adverse effects differed by therapy. These data support the use of either TAC or IFX in children with ASC refractory to intravenous corticosteroids.

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.

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.

Multicenter Cohort Study of Infliximab Pharmacokinetics and Therapy Response in Pediatric Acute Severe Ulcerative Colitis

BACKGROUND & AIMS

We aimed to model infliximab (IFX) pharmacokinetics (PK) in pediatric acute severe ulcerative colitis (ASUC) and assess the association between PK parameters, including drug exposure, and clinical response.

METHODS

We studied a multicenter prospective cohort of hospitalized children initiating IFX for ASUC or IBD-unclassified. Serial IFX serum concentrations over 26 weeks were used to develop a PK model. We tested the association of PK parameter estimates with day 7 clinical response, week 8 clinical remission, week 26 corticosteroid-free clinical remission (CSF-CR) (using the Pediatric Ulcerative Colitis Activity Index), and colectomy-free survival.

RESULTS

Thirty-eight participants received IFX (median initial dose, 9.9 mg/kg). Day 7 clinical response, week 8 clinical remission, and week 26 CSF-CR occurred in 71%, 55%, and 43%, respectively. Albumin, C-reactive protein, white blood cell count, platelets, weight, and antibodies to IFX were significant covariates incorporated into a PK model. Week 26 non-remitters exhibited faster IFX clearance than remitters (P = .013). However, cumulative IFX exposure did not differ between clinical response groups. One (2.7%) and 4 (10.8%) participants underwent colectomy by week 26 and 2 years, respectively. Day 3 IFX clearance >0.02 L/h was associated with colectomy (hazard ratio, 58.2; 95% confidence interval, 6.0-568.6; P < .001).

CONCLUSIONS

At median higher-than-label IFX dosing for pediatric ASUC, baseline faster IFX CL was associated with colectomy and at week 26 with lack of CSF-CR. IFX exposure was not predictive of clinical outcomes. Higher IFX dosing may sufficiently optimize early outcomes in pediatric ASUC. Larger studies are warranted to determine whether sustained intensification can overcome rapid clearance and improve later outcomes.

CLINICALTRIALS

gov identifier: NCT02799615.

Multi-utility of therapeutic drug monitoring in inflammatory bowel diseases

Inflammatory bowel disease (IBD) treatment targets have progressed over time from clinical response to clinical and endoscopic remission. Several data have shown a positive correlation between serum biologic drug concentrations and favorable therapeutic outcomes. Therapeutic drug monitoring (TDM) has evolved as an important approach for optimizing the use of immunobiologics, especially antitumor necrosis factor therapy, in patients with IBD. The use of TDM is supported by medical societies and IBD experts in different contexts; however, challenges remain due to knowledge gaps that limit the widespread use of it. The aim of this review is to assess the role of TDM in IBD, focusing on the implementation of this strategy in different scenarios and demonstrating the multi-utility aspects of this approach in clinical practice.

Therapeutic drug monitoring of biologics in inflammatory bowel disease: unmet needs and future perspectives

Therapeutic drug monitoring (TDM) has emerged as a useful tool for optimising the use of biologics, and in particular anti-tumour necrosis factor (anti-TNF) therapy, in inflammatory bowel disease (IBD). However, challenges remain and are hindering the widespread implementation of TDM in clinical practice. These barriers include identification of the optimal drug concentration to target, the lag time between sampling and results, and the proper interpretation of anti-drug antibody titres among different assays. Solutions to overcome these barriers include the harmonisation of TDM assays and the use of point-of-care testing. Other unmet needs include well designed prospective studies and randomised controlled trials focusing on proactive TDM, particularly during induction therapy. Future studies should also investigate the utility of TDM for biologics other than anti-TNF therapies in both IBD and other immune-mediated inflammatory diseases such as rheumatoid arthritis and psoriasis, and the use of pharmacokinetic modelling dashboards and pharmacogenetics towards individual personalised medicine.

Recent advancements in clearance monitoring of monoclonal antibodies in patients with inflammatory bowel diseases

INTRODUCTION

Less than 50% of patients with inflammatory bowel diseases (IBD) receiving monoclonal antibody (mAb) therapy achieve endoscopic remission. Poor outcomes may indicate a need for dose optimization. During therapeutic drug monitoring (TDM), drug concentrations are measured, and when found too low, dosage regimen escalations are performed. To date, benefits of TDM of mAbs in patients with IBD are uncertain.

AREAS COVERED

This review presents an overview of what clearance monitoring is, how it can be performed, and why and when it may be valuable in treating patients with IBD. Virtual patients were used for illustration. A literature search was performed to summarize current evidence for clearance monitoring in IBD and other disease settings.

EXPERT OPINION

During clearance monitoring, mAb clearance is calculated and monitored over time. Higher mAb clearance in patients with IBD has been associated with higher target load (target-mediated drug disposition), protein-losing enteropathy (fecal drug loss), and immunogenicity. Although not prospectively confirmed, clearance monitoring might facilitate identification of (yet) asymptomatic disease flares or presence of (yet) undetectable anti-drug antibodies. Furthermore, clearance monitoring may be used to predict treatment outcomes. Whether dosage regimen adjustments can modify the clearance time course and the treatment outcome is to be determined.

Therapeutic Drug Monitoring of Biologics in IBD: Essentials for the Surgical Patient

Despite significant development in the pharmacological treatment of inflammatory bowel diseases (IBD) along with the evolution of therapeutic targets and treatment strategies, a significant subset of patients still requires surgery during the course of the disease. As IBD patients are frequently exposed to biologics at the time of abdominal and perianal surgery, it is crucial to identify any potential impact of biological agents in the perioperative period. Even though detectable serum concentrations of biologics do not seem to increase postoperative complications after abdominal procedures in IBD, there is increasing evidence on the role of therapeutic drug monitoring (TDM) in the perioperative setting. This review aims to provide a comprehensive summary of published studies reporting the association of drug concentrations and postoperative outcomes, postoperative recurrence (POR) after an ileocolonic resection for Crohn’s disease (CD), colectomy rates in ulcerative colitis (UC), and perianal fistulizing CD outcomes in patients treated with biologics. Current data suggest that serum concentrations of biologics are not associated with an increased risk in postoperative complications following abdominal procedures in IBD. Moreover, higher concentrations of anti-TNF agents are associated with a reduction in colectomy rates in UC. Finally, higher serum drug concentrations are associated with reduced rates of POR after ileocolonic resections and increased rates of perianal fistula healing in CD. TDM is being increasingly used to guide clinical decision making with favorable outcomes in many clinical scenarios. However, given the lack of high quality data deriving mostly from retrospective studies, the evidence supporting the systematic application of TDM in the perioperative setting is still inconclusive.

Model-Informed Precision Dosing during Infliximab Induction Therapy Reduces Variability in Exposure and Endoscopic Improvement between Patients with Ulcerative Colitis

Model-informed precision dosing (MIPD) may be a solution to therapeutic failure of infliximab for patients with ulcerative colitis (UC), as underexposure could be avoided, and the probability of endoscopic improvement (pEI; Mayo endoscopic subscore ≤ 1) could be optimized. To investigate in silico whether this claim has merit, four induction dosing regimens were simulated: 5 mg/kg (label dosing), 10 mg/kg, covariate-based MIPD (fat-free mass, corticosteroid use, and presence of extensive colitis at baseline), and concentration-based MIPD (based on the trough concentration at day 14). Covariate- and concentration-based MIPD were chosen to target the same median area under the infliximab concentration-time curve up to endoscopy at day 84 (AUC_d84), as was predicted from 10 mg/kg dosing. Dosing at 5 mg/kg resulted in a mean ± standard deviation pEI of 55.7 ± 9.0%. Increasing the dose to 10 mg/kg was predicted to improve pEI to 65.1 ± 6.1%. Covariate-based MIPD reduced variability in exposure and pEI (65.1 ± 5.5%). Concentration-based MIPD decreased variability further (66.0 ± 3.9%) but did so at an increased average dose of 2293 mg per patient, as compared to 2168 mg for 10 mg/kg dosing. Mean pEI remained unchanged between 10 mg/kg dosing and MIPD, since the same median AUC_d84 was targeted. In conclusion, quantitative simulations predict MIPD will reduce variability in exposure and pEI between patients with UC during infliximab induction therapy.

A Comprehensive Literature Review and Expert Consensus Statement on Therapeutic Drug Monitoring of Biologics in Inflammatory Bowel Disease

Therapeutic drug monitoring (TDM) of biologics is a rapidly evolving field. We aimed to provide a consensus statement regarding the clinical utility of TDM for biologics in inflammatory bowel disease (IBD). A modified Delphi method was applied to develop consensus statements. A comprehensive literature review was performed regarding TDM of biologic therapies in IBD, and 45 statements were subsequently formulated on the potential application of TDM in IBD. The statements, along with literature, were then presented to a panel of 10 gastroenterologists with expertise in IBD and TDM who anonymously rated them on a scale of 1-10 (1 = strongly disagree and 10 = strongly agree). An expert consensus development meeting was held virtually to review, discuss, refine, and reformulate statements that did not meet criteria for agreement or that were ambiguous. During the meeting, additional statements were proposed. Panelists then confidentially revoted, and statements rated ≥7 by 80% or more of the participants were accepted. During the virtual meeting, 8 statements were reworded, 7 new statements were proposed, and 19 statements were rerated. Consensus was finally reached in 48/49 statements. The panel agreed that reactive TDM should be used for all biologics for both primary nonresponse and secondary loss of response. It was recommended that treatment discontinuation should not be considered for infliximab or adalimumab until a drug concentration of at least 10-15 μg/mL was achieved. Consensus was also achieved regarding the utility of proactive TDM for anti-tumor necrosis factor therapy. It was recommended to perform proactive TDM after induction and at least once during maintenance. Consensus was achieved in most cases regarding the utility of TDM of biologics in IBD, specifically for reactive and proactive TDM of anti-tumor necrosis factors.

Tofacitinib for Biologic-Experienced Hospitalized Patients With Acute Severe Ulcerative Colitis: A Retrospective Case-Control Study

BACKGROUND & AIMS

Despite rescue therapy, more than 30% of patients with acute severe ulcerative colitis (ASUC) require colectomy. Tofacitinib is a rapidly acting Janus kinase inhibitor with proven efficacy in ulcerative colitis. Tofacitinib may provide additional means for preventing colectomy in patients with ASUC.

METHODS

A retrospective case-control study was performed evaluating the efficacy of tofacitinib induction in biologic-experienced patients admitted with ASUC requiring intravenous corticosteroids. Tofacitinib patients were matched 1:3 to controls according to gender and date of admission. Using Cox regression adjusted for disease severity, we estimated the 90-day risk of colectomy. Rates of complications and steroid dependence were examined as secondary outcomes.

RESULTS

Forty patients who received tofacitinib were matched 1:3 to controls (n = 113). Tofacitinib was protective against colectomy at 90 days compared with matched controls (hazard ratio [HR], 0.28, 95% confidence interval [CI], 0.10-0.81; P = .018). When stratifying according to treatment dose, 10 mg three times daily (HR, 0.11; 95% CI, 0.02-0.56; P = .008) was protective, whereas 10 mg twice daily was not significantly protective (HR, 0.66; 95% CI, 0.21-2.09; P = .5). Rate of complications and steroid dependence were similar between tofacitinib and controls.

CONCLUSIONS

Tofacitinib with concomitant intravenous corticosteroids may be an effective induction strategy in biologic-experienced patients hospitalized with ASUC. Prospective trials are needed to identify the safety, optimal dose, frequency, and duration of tofacitinib for ASUC.

Biomarker dynamics during infliximab salvage for acute severe ulcerative colitis: C-reactive protein (CRP)-lymphocyte ratio and CRP-albumin ratio are useful in predicting colectomy

Background/Aims

The residual risk of colectomy after infliximab salvage in steroid-refractory acute severe ulcerative colitis (ASUC) is required to inform the need for subsequent maintenance biologic therapy. The aim of this study was to determine the dynamic response of common serum biomarkers to infliximab salvage and assess their utility in predicting subsequent colectomy.

Methods

A retrospective single-center cohort study was conducted on all patients who received infliximab salvage for steroid-refractory ASUC between January 1, 2010, and July 31, 2019. Biomarkers were assessed on admission and days 1 and 3 post infliximab, and included C-reactive protein (CRP)-albumin-ratio (CAR), CRP-lymphocyte-ratio (CLR), platelet-lymphocyte-ratio (PLR) and neutrophil-lymphocyte-ratio (NLR).

Results

Of 94 patients (median age, 35 years; 67% of male), 20% required colectomy at 12 months. Biomarkers on day 3 post-infliximab best differentiated nonresponders, who had higher CRP, lower albumin and lower lymphocyte count (each P < 0.05). Day 3 predictive performance (area under the curve) for 12-month colectomy was best for CAR (0.871) and CLR (0.874), which were similar to Lindgren (0.829; P > 0.05) but superior to Mayo (0.726), partial Mayo (0.719), PLR (0.719), Ho index (0.714), NLR (0.675), Travis score (0.657) and endoscopic Mayo (0.609) (each P < 0.05). A day 3 CAR cutoff of 0.47 mg/g had 79% sensitivity, 80% specificity, 94% negative predictive value (NPV) to predict colectomy; while a day 3 CLR cutoff of 6.0 mg/10⁹ had 84% sensitivity, 84% specificity, 96% NPV.

Conclusions

CAR and CLR measured on day 3 post infliximab salvage for steroid-refractory ASUC represent simple and routinely performed biomarkers that appear to be strong predictors of colectomy. Prospective studies are required to confirm the utility of these predictive scores.

Treatment of acute severe ulcerative colitis

Acute severe ulcerative colitis (ASUC) is a potentially life-threatening medical emergency. Due to the increasing incidence of ulcerative colitis in recent years, ASUC has become increasingly common in clinical practice. Presently, corticosteroids remain the first choice, whose efficacy should be evaluated after 3 d. If unsatisfactory, it should be switched to infliximab or cyclosporine salvage treatment timely. Besides, colectomy may be an option when medical treatment is ineffective or serious complications occur. This review describes the current treatment regimens for ASUC, with an aim to help develop treatment plans and improve the prognosis and life quality of patients with ASUC .

Predicting Therapeutic Response in Pediatric Ulcerative Colitis-A Journey Towards Precision Medicine

Ulcerative colitis (UC) is a disabling disease, characterized by chronic inflammation of the colon, with a rising prevalence worldwide in the pediatric age group. Although UC presents in children with varying severity, disease extent, and comorbidities, initial treatment is essentially uniform, consisting of 5-aminosalicylate drugs with corticosteroid induction for those with moderately to severely active disease. With the advent of anti-tumor necrosis factor (TNF) biologic therapy and several new biologics and small-molecule drugs for UC, precision medicine approaches to treatment are needed to more rapidly achieve sustained remission, restore quality of life, normalize development, and limit exposure to toxic corticosteroids in children with UC. Here, we review available data on clinical, biochemical, histopathologic, and molecular predictors of treatment response in UC. We also address known predictors and special treatment considerations in specific relevant scenarios such as very-early-onset UC, acute severe UC, ileal pouch anal anastomosis, and UC with concomitant primary sclerosing cholangitis. The review concludes with a prediction of how machine learning will integrate multimodal patient data to bring precision medicine to the bedside of children with UC in the future.