Wide variation in the use and understanding of therapeutic drug monitoring for anti-TNF agents in inflammatory bowel disease: an inexact science?

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.

Real-World Implementation and Outcomes of Adalimumab Therapeutic Drug Monitoring in Psoriasis: A National Specialized Center Experience

Serum adalimumab concentration is a biomarker of treatment response but therapeutic drug monitoring (TDM) is yet to be implemented in routine psoriasis care. We incorporated adalimumab TDM in a national specialized psoriasis service and evaluated it using the RE-AIM (Reach, Effectiveness, Adoption, Implementation, and Maintenance) implementation science framework. We undertook pre-implementation planning (validating local assays) and implementation interventions targeted to patients (pragmatic sampling at routine reviews), clinicians (introduction of a TDM protocol), and healthcare systems (adalimumab TDM as a key performance indicator). Over 5 months, 170 of 229 (74%) individuals treated with adalimumab received TDM. Clinical improvement after TDM-guided dose escalation occurred in 13 of 15 (87%) nonresponders with serum drug concentrations <8.3 μg/ml (median PASI reduction of 3.2 [interquartile range = 2.2-8.2] after 23.4 weeks) and in all nonresponders who had TDM-guided switch in biologic due to supratherapeutic drug concentrations (>8.3 μg/ml; n = 2) or positive antidrug antibody (n = 2) (PASI reduction of 7.8 [interquartile range = 7.5-12.9] after 20.0 weeks). Proactive TDM led to dose reduction in five individuals with clear skin and subtherapeutic or supratherapeutic drug concentrations; four (80%) sustained clear skin after 50 weeks (range = 42-52). Adalimumab TDM based on pragmatic serum sampling is clinically viable and may lead to patient benefit. Context-specific implementation interventions and systematic implementation assessment may bridge the biomarker research-to-practice gap.

Therapeutic drug monitoring in inflammatory bowel disease: implementation, utilization, and barriers in clinical practice in Scandinavia

BACKGROUND AND AIMS

Therapeutic drug monitoring (TDM) may optimize biologic and thiopurine therapies in inflammatory bowel disease (IBD). The study aimed to investigate implementation and utilization of TDM in Scandinavia.

METHODS

A web-based questionnaire on the use of TDM was distributed to Scandinavian gastroenterologists via the national societies.

RESULTS

In total, 297 IBD physicians prescribing biologic therapies, equally distributed between community and university hospitals, were included (response rate 42%) (Norway 118 (40%), Denmark 86 (29%), Sweden 50 (17%), Finland 33 (11%), Iceland 10 (3%)). Overall, TDM was applied during biologic therapies by 87%, and for TNF-inhibitors >90%. Among the users, reactive and proactive TDM were utilized by 90% and 63%, respectively. Danish physicians were significantly less inclined to use TDM compared to other Scandinavian countries; (58% vs 98%); OR 0.03 [0.01-0.09], p < 0.001). Reactive TDM was commonly applied at primary (74%) and secondary (99%) treatment failure. Proactive TDM was used by 80% during maintenance therapy and 56% during induction and more commonly utilized in Norway (p < 0.001), and by physicians managing >10 IBD patients/week (p = 0.005). TDM scenarios were interpreted in accord with available evidence but with discrepancies for proactive TDM. The main barriers to TDM were lack of guidelines (51%) and time lag between sampling and results (49%). TDM of thiopurines was routinely used by 87%.

CONCLUSION

TDM of biologic and thiopurine therapies has been broadly implemented into clinical practice in Scandinavia. However, physicians call for TDM guidelines detailing indications and interpretations of test results along with improved test response times.

Pharmacist-Managed Therapeutic Drug Monitoring Programs within Australian Hospital and Health Services—A National Survey of Current Practice

Pharmacist-managed therapeutic drug monitoring (TDM) services have demonstrated positive outcomes in the literature, including reduced duration of therapy and decreased incidence of the adverse effects of drug therapy. Although the evidence has demonstrated the benefits of these TDM services, this has predominately been within international healthcare systems. The extent to which pharmacist-managed TDM services exist within Australia, and the roles and responsibilities of the pharmacists involved compared to their counterparts in other countries, remains largely unknown. A cross-sectional online survey was conducted evaluating pharmacist-managed TDM programs within Australian hospital and healthcare settings. Pharmacist perceptions were also explored about the strengths, weaknesses, opportunities, and barriers associated with implementing a pharmacist-managed TDM service. A total of 92 surveys were returned, which represents a response rate of 38%. Pharmacist-managed TDM programs were present in 15% of respondents. It is only in the minority of hospitals where there is a pharmacist-managed service, with pharmacists involved in recommending pathology and medication doses. The programs highlighted improved patient outcomes but had difficulty maintaining the educational packages and training. For hospitals without a service, a lack of funding and time were highlighted as barriers. Based on the findings of this survey, there is minimal evidence of pharmacist-managed TDM models within Australian hospital and health services. A standardized national approach to pharmacist-managed TDM services and recognition of this specialist area for pharmacists could be a potential solution to this.

A systematic monitoring approach to biologic therapies in inflammatory bowel disease: patients' and physicians' preferences and adherence

OBJECTIVES

Treatment of patients with inflammatory bowel disease (IBD) should aim at achieving mucosal healing. However, monitoring schedules to support this goal remain undefined. We aimed to identify patients' and physicians' preferences regarding monitoring strategy and investigated the feasibility of such a strategy.

METHODS

Elements considered relevant for monitoring were identified in questionnaire surveys among 1) patients with IBD receiving biologic agents (n = 172) and 2) their physicians (n = 87). Adherence to a monitoring strategy incorporating these elements was investigated in a retrospective cohort of patients with IBD treated with biologic agents (n = 139).

RESULTS

Patients considered blood and stool samples, endoscopies, and magnetic resonance imaging (MRI) to be relevant aspects of monitoring their disease. However, patients also considered stool samples and endoscopies unpleasant. Physicians considered blood samples (99%), medical consultations (99%), fecal calprotectin (85%), endoscopy (78%), and MRI (71%) to be important aspects of IBD monitoring but considered endoscopies and MRI relevant only at clinical signs of relapse. A review of the clinical use of monitoring strategies including the elements identified above revealed high adherence for blood samples and disease activity indices (92%), but low adherence for fecal calprotectin (38%), therapeutic drug monitoring (38%), and endoscopies (32%).

CONCLUSION

Important tools for evaluating mucosal healing (e.g., endoscopy) were rated highly unpleasant by patients, and physicians found endoscopies/MRI relevant only in case of relapse. These findings were reflected by low rates of adherence to use of these monitoring tools. In defining monitoring schedules to help achieve treatment goals, these important barriers must be addressed.

Value-based care pathway for inflammatory bowel disease: a protocol for the multicentre longitudinal non-randomised parallel cluster IBD Value study with baseline period

INTRODUCTION

Biologics are effective for the treatment of inflammatory bowel disease (IBD). However, unwarranted variation in processes and outcomes has been reported in the treatment of IBD. A care pathway for the treatment of IBD has the potential to reduce practice variation and improve outcomes. This study aims to compare the effect of a uniform care pathway for the treatment of patients with IBD with biologics to the current situation.

METHODS AND ANALYSIS

IBD Value is a longitudinal multicentre non-randomised parallel cluster trial with a baseline period. The study takes place in eight centres in the Netherlands. The baseline period will run for 12 months, after which the care pathway will be implemented in 6 of the 8 participating hospitals during the implementation phase of 3 months. Hereafter, the effect of the care pathway will be assessed for 12 months. Total study period is 27 months. The primary outcome is the effect of the care pathway on disease control (IBD-Control questionnaire). Secondary outcomes are the effect of the care pathway on the other outcomes of the International Consortium of Health Outcomes Measurement IBD standard set, health-related generic quality of life, patient experiences and degree of variation; cost effectiveness of the care pathway; and the variation between hospitals in the aforementioned outcomes in the baseline period. Outcomes will be measured every 6 months. The study started on 1 December 2020 and a minimum of 200 patients will be included.

ETHICS AND DISSEMINATION

The study was deemed not to be subject to Dutch law (WMO; Medical Research Involving Human Subjects Act) by the Medical Ethics Committee of the Erasmus MC, the Netherlands (registration number: MEC-2020-075) and a waiver was provided. Results will be disseminated through peer-reviewed journals and presented at (inter)national conferences.

TRIAL REGISTRATION NUMBER

NL8276.

Infliximab Therapeutic Drug Monitoring in Inflammatory Bowel Disease Virtual Biologics Clinic Leads to Durable Clinical Results

Background

Therapeutic drug monitoring (TDM) of infliximab (IFX) trough levels and anti-drug antibodies in conjunction with symptoms, disease history, and investigations can aid decision-making. This study evaluated 1-year outcomes of patients with decisions that were altered on the basis of TDM results, in order to investigate whether outcomes from TDM-based decisions to adjust or stop IFX treatment are durable.

Methods

We retrospectively collected clinical outcomes 12 months post treatment decisions based on proactive TDM. Patients whose initial treatment decisions were altered on the basis of TDM results were compared with those where the decision remained unchanged. Events of interest were inpatient admissions with active inflammatory bowel disease (IBD), further changes to biologic therapy, and IBD-related health-care costs.

Results

Of 189 patients, 54 (28%) had initial treatment decisions altered in the light of TDM results. The 135 patients whose initial decision was not altered in light of TDM results served as the comparator. There were no differences in hospitalization rates or subsequent biologic switches between the altered decision groups and the comparator group. IBD-related health-care costs were higher in those whose initial decision was altered (median GBP 7,912 vs. GBP 6,521; p < 0.0001) due to higher drug costs (median GBP 7,062 vs. GBP 6,012; p < 0.0001).

Conclusion

Our study demonstrates good outcomes from changes to IFX treatment based on TDM. Patients with a decision to stop, switch, or continue with an adjusted IFX dose experienced comparable clinical outcomes but had higher drug-related expenditure than those whose treatment decision was not altered in light of TDM.

Drug Levels Associated with Optimal Discrimination Between Remission and Non-Remission and Comparison of Antibody Assays During First Year of Stable Infliximab Maintenance Therapy in Inflammatory Bowel Disease

BACKGROUND

In order to implement therapeutic drug monitoring (TDM)-based strategies for infliximab (IFX) in inflammatory bowel disease (IBD), the authors assessed IFX levels for optimal discrimination between remission and non-remission and compared assays for anti-IFX antibodies (Abs).

METHODS

The retrospective cohort comprised 163 bionaïve patients with IBD who received stable IFX maintenance therapy (5 mg/kg every 8 weeks [q8w]) for one year. The clinical and biochemical remission status was assessed at all infusions (weeks 14-22-30-38-46-54), and IFX and anti-IFX Abs were estimated using a time-resolved fluorometric assay (n=690; 88% of infusions). Samples positive for anti-IFX Abs or IFX levels <limit of detection (LOD; n=102) were analyzed by two binding assays (ELISA) and functional reporter gene assay/drug-tolerant enzyme immunoassay (RGA/EIA).

RESULTS

At all assessed time points, IFX levels were more than double in patients presenting clinical or biochemical remission. An IFX concentration of 4.5 µg/mL was associated with clinical remission during the entire first year of therapy (sensitivity 54% [49-59], specificity 73% [67-78], AUCROC 0.65 [0.60-0.69], p<0.0001); these values were comparable with biochemical remission. Exploratory assessments for endoscopic remission (n=131) were performed at the discretion of the treating physician. Anti-IFX Abs were associated with undetectable IFX and treatment failure (OR 2.9 [1.4-6.0], p<0.01), irrespective of persistency or transiency. All performed assays detected anti-IFX Abs in [SWUNG DASH]2/3 of samples. Binding assays demonstrated a higher sensitivity to anti-IFX Abs.

CONCLUSION

IFX at [SWUNG DASH]5 µg/mL was associated with clinical and biochemical remission during the first year of maintenance therapy. During this phase of therapy, standard binding assays are appropriate for TDM.

Treat-to-target approach in the management of inflammatory Bowel disease

With the advent of biologic and small molecule therapies, there has been a substantial change in the treatment of inflammatory bowel disease. These advances have had a great impact in preventing disease progression, intestinal damage and, therefore, have contributed to a better quality of life. Discordance between symptom control and mucosal healing has been demonstrated. This has led to the search for new disease control targets. The treat to target strategy, based on expert recommendations and now a randomized controlled trial, has determined that clinical and endoscopic remission should be the goal of therapy. Biomarkers (fecal calprotectin) can be a surrogate target. Although histological healing has shown benefits, there is inadequate evidence and inadequate therapy for that to be a fixed goal at this time. This review will focus on therapeutic goals, according to the evidence currently available, and evaluate strategies to achieve them.

An Indian national survey of therapeutic drug monitoring with anti-tumor necrosis (TNF) medications in inflammatory bowel disease

BACKGROUND

Evidence supports therapeutic drug monitoring (TDM) in improving efficacy and cost-effectiveness of anti-TNF therapy in inflammatory bowel disease (IBD). Data on perceptions and barriers to TDM use are limited and no data are available from India. Our objective was to assess clinicians' attitudes and barriers to TDM use in IBD.

METHODS

A 16-question survey was distributed to members of the Indian Society of Gastroenterology. Information on clinician characteristics, demographics, use and barriers towards TDM with anti-TNFs was collected. Logistic regression was used to predict factors influencing TDM use.

RESULTS

Two hundred and forty-two respondents participated (92.5% male); 83% were consultant gastroenterologists. Of 104 respondents meeting inclusion criteria (treating > 5 IBD patients and at least 1 with an anti-TNF per month), complete responses were available for 101 participants. TDM was utilized by 20% (n = 20) of respondents. Of them, 89.5% (n = 17) used TDM for secondary loss of response; 73.7% (n = 14) for primary non-response and 5.3% (n = 1) proactively. Barriers to TDM use were cost (71.2%), availability (67.8%), time lag in results (58.7%) and the perception that TDM is time-consuming (45.7%). Clinicians treating > 30 IBD patients were more likely to check TDM (OR = 4.9, p = 0.02). Of 81 respondents not using TDM, 97.5% (n = 79) would do so if all the barriers were removed.

CONCLUSION

Significant barriers to TDM use were availability, cost and time lag for results. If these barriers were removed, almost all the clinicians would use TDM at least reactively and 25% would use proactively. There is an urgent need to address these barriers and optimize anti-TNF therapy for optimal outcomes.

A 3-year prospective study of a multidisciplinary early proactive therapeutic drug monitoring programme of infliximab treatments in inflammatory bowel disease

AIMS

Therapeutic drug monitoring (TDM) of trough serum infliximab concentrations has been mainly used in case of loss of response in patients with inflammatory bowel disease (IBD). The aim of this study was to evaluate the effectiveness and safety of a multidisciplinary early proactive TDM (mep-TDM) programme for dose adjustment.

METHODS

A 3-year prospective study was conducted based on a sample of 81 patients who started treatment and were subsequently subjected to mep-TDM with the first control at week 14. Data of a historical control group of 72 patients treated with infliximab and managed with empirical dosing were included. Effectiveness variables were treatment failure, IBD-related surgery and IBD-related hospitalization. Safety variables were serious infusion reactions (SIRs) and adverse reactions. Cox regression was used for survival analysis.

RESULTS

In the mep-TDM study group, compared to the control group, there was a significant reduction in the risk of treatment failure (hazard ratio [HR]: 0.51; 95% confidence interval [CI]: 0.27-0.92; P = .037), IBD-related surgery (HR: 0.14; 95% CI: 0.03-0.65; P = .012) and hospitalization (HR: 0.38; 95% CI: 0.17-0.87; P = .022). SIRs were lower in the mep-TDM group (2.5% vs 10.4%; P < .050); the incidence of adverse reactions was similar (3.7% vs 3.9%; p > .999).

CONCLUSION

This study found that compared to empirical dosing, mep-TDM is associated with improved efficacy and safety of infliximab therapy, reduced IBD-related hospitalization and surgery and incidence of SIRs, and increasing long-term durability of treatment effects.

UK National Survey of Gastroenterologists' attitudes and barriers toward therapeutic drug monitoring of anti-TNF therapy in inflammatory bowel disease

BACKGROUND

Evidence supports use of therapeutic drug monitoring (TDM) in improving efficacy and cost-effectiveness of anti-tumour necrosis factor (TNF) therapy in inflammatory bowel disease (IBD). Our objective was to assess attitudes and barriers towards TDM use with anti-TNF's in the UK.

METHODS

A 17-question survey was distributed to members of the British Society of Gastroenterology by email.

RESULTS

Of 243 respondents (51.6% male), 237 respondents met inclusion criteria. Of these, 46% were consultants (gastroenterologist, GI), 39.2% IBD nurse specialists (clinical nurse specialists, CNS), 14.8% registrars. TDM is used by 96.9% for secondary loss of response; 72.5% for primary non-response and 54.1% used TDM proactively. Barriers were time lag in receiving results (49.8%), lack of awareness of guidelines (46.4%) and cost (29.9%). Clinicians working at a teaching hospital (OR 2.6, 95% CI 0.71 to 9.8), IBD CNS and GI registrars (OR 2.6, 95% CI 0.7 to 10 and OR 1.5, 95% CI 0.3 to 7.2, respectively) were more likely to use TDM. Clinicians practising for >20 years (OR 4.1, 95% CI 0.4 to 41.8) and a large volume IBD practice (>50% IBD patients per month) were more likely to use TDM (OR 45.7, 95% CI 7.5 to 275). Proactive TDM, was more likely to be used in tertiary care (OR 2.25, 95% CI 0.84 to 6.1), IBD CNS (OR 1.2, 95% CI 0.7 to 2.1) and clinicians managing >50% IBD patients per month (OR 10.8, 95% CI 1.3 to 90.3). Clinicians with 5-9 years of experience in practice were more likely to use proactive TDM (OR 2.6 and CI 1.04 to 6.4).

CONCLUSION

Validation of point of care and lower cost assays, reduced time lag from test to result, lower cost of testing and dissemination of current recommendations may further optimise treatment strategies.