Optimizing Therapies Using Therapeutic Drug Monitoring: Current Strategies and Future Perspectives

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.

Mechanisms and management of loss of response to anti-TNF therapy for patients with Crohn's disease: 3-year data from the prospective, multicentre PANTS cohort study

BACKGROUND

We sought to report the effectiveness of infliximab and adalimumab over the first 3 years of treatment and to define the factors that predict anti-TNF treatment failure and the strategies that prevent or mitigate loss of response.

METHODS

Personalised Anti-TNF therapy in Crohn's disease (PANTS) is a UK-wide, multicentre, prospective observational cohort study reporting the rates of effectiveness of infliximab and adalimumab in anti-TNF-naive patients with active luminal Crohn's disease aged 6 years and older. At the end of the first year, sites were invited to enrol participants still receiving study drug into the 2-year PANTS-extension study. We estimated rates of remission across the whole cohort at the end of years 1, 2, and 3 of the study using a modified survival technique with permutation testing. Multivariable regression and survival analyses were used to identify factors associated with loss of response in patients who had initially responded to anti-TNF therapy and with immunogenicity. Loss of response was defined in patients who initially responded to anti-TNF therapy at the end of induction and who subsequently developed symptomatic activity that warranted an escalation of steroid, immunomodulatory, or anti-TNF therapy, resectional surgery, or exit from study due to treatment failure. This study was registered with ClinicalTrials.gov, NCT03088449, and is now complete.

FINDINGS

Between March 19, 2014, and Sept 21, 2017, 389 (41%) of 955 patients treated with infliximab and 209 (32%) of 655 treated with adalimumab in the PANTS study entered the PANTS-extension study (median age 32·5 years [IQR 22·1-46·8], 307 [51%] of 598 were female, and 291 [49%] were male). The estimated proportion of patients in remission at the end of years 1, 2, and 3 were, for infliximab 40·2% (95% CI 36·7-43·7), 34·4% (29·9-39·0), and 34·7% (29·8-39·5), and for adalimumab 35·9% (95% CI 31·2-40·5), 32·9% (26·8-39·2), and 28·9% (21·9-36·3), respectively. Optimal drug concentrations at week 14 to predict remission at any later timepoints were 6·1-10·0 mg/L for infliximab and 10·1-12·0 mg/L for adalimumab. After excluding patients who had primary non-response, the estimated proportions of patients who had loss of response by years 1, 2, and 3 were, for infliximab 34·4% (95% CI 30·4-38·2), 54·5% (49·4-59·0), and 60·0% (54·1-65·2), and for adalimumab 32·1% (26·7-37·1), 47·2% (40·2-53·4), and 68·4% (50·9-79·7), respectively. In multivariable analysis, loss of response at year 2 and 3 for patients treated with infliximab and adalimumab was predicted by low anti-TNF drug concentrations at week 14 (infliximab: hazard ratio [HR] for each ten-fold increase in drug concentration 0·45 [95% CI 0·30-0·67], adalimumab: 0·39 [0·22-0·70]). For patients treated with infliximab, loss of response was also associated with female sex (vs male sex; HR 1·47 [95% CI 1·11-1·95]), obesity (vs not obese 1·62 [1·08-2·42]), baseline white cell count (1·06 [1·02-1·11) per 1 × 109 increase in cells per L), and thiopurine dose quartile. Among patients treated with adalimumab, carriage of the HLA-DQA1*05 risk variant was associated with loss of response (HR 1·95 [95% CI 1·17-3·25]). By the end of year 3, the estimated proportion of patients who developed anti-drug antibodies associated with undetectable drug concentrations was 44·0% (95% CI 38·1-49·4) among patients treated with infliximab and 20·3% (13·8-26·2) among those treated with adalimumab. The development of anti-drug antibodies associated with undetectable drug concentrations was significantly associated with treatment without concomitant immunomodulator use for both groups (HR for immunomodulator use: infliximab 0·40 [95% CI 0·31-0·52], adalimumab 0·42 [95% CI 0·24-0·75]), and with carriage of HLA-DQA1*05 risk variant for infliximab (HR for carriage of risk variant: infliximab 1·46 [1·13-1·88]) but not for adalimumab (HR 1·60 [0·92-2·77]). Concomitant use of an immunomodulator before or on the day of starting infliximab was associated with increased time without the development of anti-drug antibodies associated with undetectable drug concentrations compared with use of infliximab alone (HR 2·87 [95% CI 2·20-3·74]) or introduction of an immunomodulator after anti-TNF initiation (1·70 [1·11-2·59]). In years 2 and 3, 16 (4%) of 389 patients treated with infliximab and 11 (5%) of 209 treated with adalimumab had adverse events leading to treatment withdrawal. Nine (2%) patients treated with infliximab and two (1%) of those treated with adalimumab had serious infections in years 2 and 3.

INTERPRETATION

Only around a third of patients with active luminal Crohn's disease treated with an anti-TNF drug were in remission at the end of 3 years of treatment. Low drug concentrations at the end of the induction period predict loss of response by year 3 of treatment, suggesting higher drug concentrations during the first year of treatment, particularly during induction, might lead to better long-term outcomes. Anti-drug antibodies associated with undetectable drug concentrations of infliximab, but not adalimumab, can be predicted by carriage of HLA-DQA1*05 and mitigated by concomitant immunomodulator use for both drugs.

FUNDING

Guts UK, Crohn's and Colitis UK, Cure Crohn's Colitis, AbbVie, Merck Sharp and Dohme, Napp Pharmaceuticals, Pfizer, and Celltrion Healthcare.

Impact of antitumour necrosis factor therapy on surgery in inflammatory bowel disease: a population-based study

OBJECTIVE

It is unclear whether widespread use of biologics is reducing inflammatory bowel disease (IBD) surgical resection rates. We designed a population-based study evaluating the impact of early antitumour necrosis factor (TNF) on surgical resection rates up to 5 years from diagnosis.

DESIGN

We evaluated all patients with IBD diagnosed in Cardiff, Wales 2005-2016. The primary measure was the impact of early (within 1 year of diagnosis) sustained (at least 3 months) anti-TNF compared with no therapy on surgical resection rates. Baseline factors were used to balance groups by propensity scores, with inverse probability of treatment weighting (IPTW) methodology and removing immortal time bias. Crohn's disease (CD) and ulcerative colitis (UC) with IBD unclassified (IBD-U) (excluding those with proctitis) were analysed.

RESULTS

1250 patients were studied. For CD, early sustained anti-TNF therapy was associated with a reduced likelihood of resection compared with no treatment (IPTW HR 0.29 (95% CI 0.13 to 0.65), p=0.003). In UC including IBD-U (excluding proctitis), there was an increase in the risk of colectomy for the early sustained anti-TNF group compared with no treatment (IPTW HR 4.6 (95% CI 1.9 to 10), p=0.001).

CONCLUSIONS

Early sustained use of anti-TNF therapy is associated with reduced surgical resection rates in CD, but not in UC where there was a paradoxical increased surgery rate. This was because baseline clinical factors were less predictive of colectomy than anti-TNF usage. These data support the use of early introduction of anti-TNF therapy in CD whereas benefit in UC cannot be assessed by this methodology.

Forecasted infliximab concentrations during induction predict time to remission and sustained disease control of inflammatory bowel disease

BACKGROUND

Infliximab (IFX) exposure is established as a predictive factor of pharmacokinetic (PK) origin in inflammatory bowel disease (IBD), and expert consensus is to achieve adequate exposure during induction to achieve and sustain remission.

METHODS

We retrospectively evaluated the performance of a Bayesian PK tool in IBD patients starting IFX. Trough IFX serum levels collected immediately before the third (at week 6) and fourth (at week 14) infusions were evaluated from 307 IBD patients (median age=17 years, 50 % females, 83 % with Crohn's disease). Forecasted IFX concentration at the fourth infusion were estimated using serum IFX, antibodies to IFX, albumin and weight determined immediately before the third infusion using population PK calculator with Bayesian prior. The outcome variable was a clinical & biochemical remission status achieved (CRP levels below 3 mg/L in presence of clinical remission). Statistics consisted of Kaplan Meier analysis with calculation of Hazard ratio (HR), and logistic regression.

RESULTS

IFX concentration above 15 µg/mL immediately before the third infusion associated with shorter time to clinical & biochemical remission than concentration below 15 µg/mL without reaching significance (163±14 days vs 200±16 days, respectively; p=0.052). However, using PK parameters at the third infusion, forecasted IFX concentrations above 10 µg/mL immediately before the fourth infusion were significantly associated with a higher rate (HR=1.6 95 %CI: 1.1 to 2.1 p<0.01) and shorter time to remission (148±18 days vs 200±13 days p<0.01). In the presence of IFX concentration above 15 µg/mL at the third infusion, there was a significant 2.5-fold higher likelihood of sustained clinical & biochemical remission status during maintenance as compared to IFX concentrations below 15 µg/mL (p<0.01). Forecasted IFX level above 10 µg/mL at fourth infusion associated with significantly 3.9-fold higher likelihood of clinical & biochemical remission as compared to forecasted IFX concentrations below 10 µg/mL (p<0.01).

CONCLUSIONS

These data further support that optimized IFX concentrations during induction are associated with enhanced disease control in IBD.

White Paper: American Gastroenterological Association Position Statement: The Future of IBD Care in the United States-Removing Barriers and Embracing Opportunities

Despite incredible growth in systems of care and rapidly expanding therapeutic options for people with inflammatory bowel disease, there are significant barriers that prevent patients from benefiting from these advances. These barriers include restrictions in the form of prior authorization, step therapy, and prescription drug coverage. Furthermore, inadequate use of multidisciplinary care and inflammatory bowel disease specialists limits patient access to high-quality care, particularly for medically vulnerable populations. However, there are opportunities to improve access to high-quality, patient-centered care. This position statement outlines the policy and advocacy goals that the American Gastroenterological Association will prioritize for collaborative efforts with patients, providers, and payors.

Systematic Review and Meta-analysis: The Association Between Serum Ustekinumab Trough Concentrations and Treatment Response in Inflammatory Bowel Disease

BACKGROUND

Optimizing therapy and monitoring response are integral aspects of inflammatory bowel disease treatment. We conducted a systematic review and meta-analysis to determine whether serum ustekinumab trough concentrations during maintenance therapy were associated with ustekinumab treatment response in patients with inflammatory bowel disease.

METHODS

A systematic review was performed to March 21, 2022, to identify studies using MEDLINE, EMBASE, and the Cochrane library. We included studies that reported the association between serum ustekinumab trough concentrations with clinical or endoscopic remission. Outcome measures were combined across studies using the random-effects model with an odds ratio (OR) for binary outcomes of endoscopic and clinical remission.

RESULTS

We identified 14 observational studies that were included in the analysis for clinical remission (919 patients, 63% with Crohn's disease) or endoscopic remission (290 patients, all with Crohn's disease). Median ustekinumab trough concentrations were higher amongst individuals achieving clinical remission compared with those not achieving remission (mean difference, 1.6 ug/mL; 95% confidence interval [CI], 0.21-3.01 ug/mL). Furthermore, individuals with median serum trough concentration in the fourth quartile were significantly more likely to achieve clinical (OR, 3.61; 95% CI, 2.11-6.20) but not endoscopic remission (OR, 4.67; 95% CI, 0.86-25.19) compared with those with first quartile median trough concentrations.

CONCLUSION

Based on the results of this meta-analysis primarily relating to patients with Crohn's disease on maintenance ustekinumab treatment, it appears that there is an association between higher ustekinumab trough concentration and clinical outcomes. Prospective studies are required to determine whether proactive dose adjustments of ustekinumab therapy provides additional clinical benefit.

Greenness assessment of microextraction techniques in therapeutic drug monitoring

Aim: In this study, we evaluated the greenness and whiteness scores for microextraction techniques used in therapeutic drug monitoring. Additionally, the cons and pros of each evaluated method and their impacts on the provided scores are also discussed. Materials & methods: The Analytical Greenness Sample Preparation metric tool and white analytical chemistry principles are used for related published works (2007-2023). Results & conclusion: This study provided valuable insights for developing methods based on microextraction techniques with a balance in greenness and whiteness areas. Some methods based on a specific technique recorded higher scores, making them suitable candidates as green analytical approaches, and some others achieved high scores both in green and white areas with a satisfactory balance between principles.

Is tumor necrosis factor-α monoclonal therapy with proactive therapeutic drug monitoring optimized for inflammatory bowel disease? Network meta-analysis

BACKGROUND

The efficacy and safety of anti-tumor necrosis factor-α (TNF-α) monoclonal antibody therapy [adalimumab (ADA) and infliximab (IFX)] with therapeutic drug monitoring (TDM), which has been proposed for inflammatory bowel disease (IBD) patients, are still controversial.

AIM

To determine the efficacy and safety of anti-TNF-α monoclonal antibody therapy with proactive TDM in patients with IBD and to determine which subtype of IBD patients is most suitable for proactive TDM interventions.

METHODS

As of July 2023, we searched for randomized controlled trials (RCTs) and observational studies in PubMed, Embase, and the Cochrane Library to compare anti-TNF-α monoclonal antibody therapy with proactive TDM with therapy with reactive TDM or empiric therapy. Pairwise and network meta-analyses were used to determine the IBD patient subtype that achieved clinical remission and to determine the need for surgery.

RESULTS

This systematic review and meta-analysis yielded 13 studies after exclusion, and the baseline indicators were balanced. We found a significant increase in the number of patients who achieved clinical remission in the ADA [odds ratio (OR) = 1.416, 95% confidence interval (CI): 1.196-1.676] and RCT (OR = 1.393, 95%CI: 1.182-1.641) subgroups and a significant decrease in the number of patients who needed surgery in the proactive vs reactive (OR = 0.237, 95%CI: 0.101-0.558) and IFX + ADA (OR = 0.137, 95%CI: 0.032-0.588) subgroups, and the overall risk of adverse events was reduced (OR = 0.579, 95%CI: 0.391-0.858) according to the pairwise meta-analysis. Moreover, the network meta-analysis results suggested that patients with IBD treated with ADA (OR = 1.39, 95%CI: 1.19-1.63) were more likely to undergo TDM, especially in comparison with patients with reactive TDM (OR = 1.38, 95%CI: 1.07-1.77).

CONCLUSION

Proactive TDM is more suitable for IBD patients treated with ADA and has obvious advantages over reactive TDM. We recommend proactive TDM in IBD patients who are treated with ADA.

Therapeutic drug monitoring in inflammatory bowel disease: A practical approach

The global burden of inflammatory bowel diseases (IBD) is estimated at 4.9 million and the global prevalence exceeds 0.3%. Multiple newer therapeutic agents have broadened the options for the therapy of IBD in the last three decades. Thiopurines, however, have retained their place as maintenance therapy in IBD, especially in resource-constrained setting. But thiopurines have narrow therapeutic range, often needing discontinuation due to side effects or lack of efficacy. Biologic agents revolutionized the treatment of IBD, but the efficacy is lost in 50% of patient after one year. These outcomes are often due to inadequate drug concentrations that may lead to the development of antibodies as well as pharmacodynamic failure. Therapeutic drug monitoring (TDM) was proposed to reduce loss of response and to optimize the therapy in patients on thiopurine and biologic therapy. TDM is based on exposure-response relationship, suggesting a positive correlation between elevated serum anti-TNF concentrations and favorable therapeutic outcomes. TDM has multiple facets. This article discusses the benefits, evidence and limitations of TDM. The practical use of TDM in clinical practice is highlighted. Newer developments in the field and their relevance in practice are discussed.

Baseline Clinical Factors Are Associated With Risk of Complications in Crohn's Disease: Appraisal of the American Gastroenterological Association Clinical Care Pathway

INTRODUCTION

The American Gastroenterological Association (AGA) has compiled risk factors that may be predictive of disease complications in Crohn's disease (CD) and ulcerative colitis (UC). The aim of this study was to evaluate the performance of the AGA risk factors for risk stratification in UC and CD.

METHODS

We included participants of 2 cohorts: the Ocean State Crohn's and Colitis Area Registry cohort and the Mayo Clinic cohort. Baseline clinical risk factors were extracted according to the AGA pathway. Our primary end point was defined as follows: (i) any inflammatory bowel disease related-hospitalization, (ii) any inflammatory bowel disease-related bowel surgery, or (iii) any progression of disease. We analyzed the association of the number of AGA risk factors with our end point. Statistical multivariable modeling was performed with Cox proportional hazards model.

RESULTS

A total of 412 patients with CD were included. Comparing ≥3 risk factors with 0-1 risk factor, we found a significantly increased risk of complications in both the Ocean State Crohn's and Colitis Area Registry cohort (hazard ratio [HR] 2.75, 95% confidence interval 1.71-4.41) and Mayo Clinic cohort (HR 2.07, 95% confidence interval 1.11-3.84). Diagnosis at younger age (HR 2.07), perianal disease (HR 1.99), and B2/B3 behavior (HR 1.92) were significantly associated with disease complications. We did not observe a consistent association between number of risk factors nor any specific individual risk factors and risk of disease complications in the 265 patients with UC included.

DISCUSSION

We found a significant association between the number of AGA risk factors and the risk of disease complication in CD; this association was not significant in UC. The presence of ≥ 3 risk factors in CD leads to the highest risk of complications. The AGA care pathway is a useful tool to stratify patients who are at higher risk of disease complications in patients with CD.

Overview of therapeutic drug monitoring and clinical practice

With the rapid development of clinical pharmacy in China, therapeutic drug monitoring (TDM) has become an essential tool for guiding rational clinical drug use and is widely concerned. TDM is a tool that combines pharmacokinetic and pharmacodynamic knowledge to optimize personalized drug therapy, which can improve treatment outcomes, reduce drug-drug toxicity, and avoid the risk of developing drug resistance. To effectively implement TDM, accurate and sophisticated analytical methods are required. By researching the literature published in recent years, we summarize the types of commonly monitored drugs, therapeutic windows, and clinical assays and track the trends and hot spots of therapeutic drug monitoring. The purpose is to provide guidelines for clinical blood drug concentration monitoring, to implement individualized drug delivery programs better, to ensure the rational use of drugs for patients, and to provide a reference for the group to carry out related topics in the future.

3D Printing of Dietary Products for the Management of Inborn Errors of Intermediary Metabolism in Pediatric Populations

The incidence of Inborn Error of Intermediary Metabolism (IEiM) diseases may be low, yet collectively, they impact approximately 6-10% of the global population, primarily affecting children. Precise treatment doses and strict adherence to prescribed diet and pharmacological treatment regimens are imperative to avert metabolic disturbances in patients. However, the existing dietary and pharmacological products suffer from poor palatability, posing challenges to patient adherence. Furthermore, frequent dose adjustments contingent on age and drug blood levels further complicate treatment. Semi-solid extrusion (SSE) 3D printing technology is currently under assessment as a pioneering method for crafting customized chewable dosage forms, surmounting the primary limitations prevalent in present therapies. This method offers a spectrum of advantages, including the flexibility to tailor patient-specific doses, excipients, and organoleptic properties. These elements are pivotal in ensuring the treatment's efficacy, safety, and adherence. This comprehensive review presents the current landscape of available dietary products, diagnostic methods, therapeutic monitoring, and the latest advancements in SSE technology. It highlights the rationale underpinning their adoption while addressing regulatory aspects imperative for their seamless integration into clinical practice.

Adalimumab Drug Levels at Secondary Loss of Response Do Not Predict Response to Dose-intensification in Crohn's Disease: A Retrospective, International Multicenter Study

BACKGROUND

The exposure-response relationship is less established for adalimumab (ADA) compared with infliximab in inflammatory bowel disease (IBD). Evidence supporting therapeutic drug monitoring post dose-intensification of ADA is limited. We aimed to explore the association between ADA drug levels and Crohn's disease (CD) activity at loss of response, and at 6 and 12 months post dose-intensification.

METHODS

We performed a retrospective study of adult patients with CD receiving dose-intensified weekly ADA following secondary loss of response at 3 tertiary centers across 5 years. ADA trough levels were analyzed using a drug-sensitive enzyme-linked immunosorbent assay at loss of response, and 6 and 12 months after dose-intensification. Rates of clinical remission, objective remission (C-reactive protein <5 mg/L, fecal calprotectin <150 µg/g, or absence of inflammation at endoscopy or imaging), and ADA failure were investigated.

RESULTS

A total of 131 CD patients were included, with a median disease duration of 9 (interquartile range, 4-17) years. 51% were biologic exposed prior to ADA and 50% received concomitant immunomodulators. Baseline drug levels measured at secondary loss of response did not discriminate between subsequent responders and non-responders at either 6 or 12 months post dose-intensification. However, both higher drug levels at 6 and 12 months and a higher increment from baseline were associated with improved outcomes. On receiver-operating characteristic analyses, post-escalation ADA drug levels >10.7 µg/mL (area under the receiver-operating characteristic curve [AUROC], 0.66; P = .013) and >10.9 µg/mL (AUROC, 0.67; P = .032) were associated with objective remission at 6 and 12 months, respectively.

CONCLUSIONS

Drug levels following dose-intensification rather than at the time of secondary loss of response were associated with subsequent CD remission.

Bioadhesive Microcarriers Encapsulated with IL-27 High Expressive MSC Extracellular Vesicles for Inflammatory Bowel Disease Treatment

Mesenchymal stem cell (MSC) therapy is a promising candidate for inflammatory bowel disease (IBD) treatment, while overcoming the limitations of naive seeding cells function and realizing efficient intestinal targeting remains a challenge. Here, a bioadhesive microparticle carrying interleukin-27 (IL-27) MSC-derived extracellular vesicles (MSCIL-27 EVs) is developed to treat IBD. The MSCIL-27 EVs prepared through lentivirus-mediated gene transfection technology show ideal anti-inflammatory and damage repair function. By encapsulating MSCIL-27 EVs into dopamine methacrylamide-modified hydrogel, a bioadhesive EVs microcarrier via microfluidic technology is fabricated. The resultant microcarriers exhibit ideal MSCIL-27 EVs sustained release effect and effective wet adhesion property. Furthermore, the therapeutic potential of MSCIL-27 EVs-loaded microcarriers in treating IBD is demonstrated. Through giving IBD rats a rectal administration, it is found that the microcarriers can firmly anchor to the surface of colon, reduce the inflammatory response, and repair the damaged barrier. Therefore, the bioadhesive MSCIL-27 EVs-loaded microcarriers provide a promising strategy for the biomedical application of MSC-derived EVs, and broaden the clinical potential of MSC therapy.

A Review of Therapeutic Drug Monitoring in Patients with Inflammatory Bowel Disease Receiving Combination Therapy

Background: Inflammatory Bowel Disease (IBD) impacts millions worldwide, presenting a major challenge to healthcare providers and patients. The advent of biologic therapies has enhanced the prognosis, but many patients exhibit primary or secondary non-response, underscoring the need for rigorous monitoring and therapy optimization to improve outcomes. Objective: This narrative review seeks to understand the role of therapeutic drug monitoring (TDM) in optimizing treatment for IBD patients, especially for those on combination therapies of biologics and immunomodulators. Methods: A comprehensive synthesis of the current literature was undertaken, focusing on the application, benefits, limitations, and future directions of TDM in patients receiving a combination of biologic therapies and immunomodulators. Results: While biological therapies have improved outcomes, rigorous monitoring and therapy optimization are needed. TDM has emerged as a pivotal strategy, enhancing outcomes cost-effectively while reducing adverse events. While most data pertain to monotherapies, TDM's applicability also extends to combination therapy. Conclusion: TDM plays a crucial role in the treatment optimization of IBD patients on combination therapies. Further research is needed to fully understand its potential and limitations in the broader context of IBD management.

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.

One year of experience with combined pharmacokinetic/pharmacogenetic monitoring of anti-TNF alpha agents: a retrospective study

Anti-tumor necrosis factor alpha (anti-TNFα) inhibitors are used extensively for the management of moderate to severe inflammatory bowel disease (IBD) in both adult and pediatric patients. Unfortunately, not all patients show an optimal response to induction therapy, while others lose their response over time for reasons yet poorly understood. We report on a pharmacokinetic/pharmacogenetic approach to monitor the therapy with anti-TNFα in a real-world cohort of seventy-nine pediatric patients affected by IBD that was analyzed retrospectively. We evaluated plasma concentrations of infliximab, adalimumab, and related anti-drug antibodies (ADAs), and single nucleotide polymorphisms (SNPs) in genes involved in immune processes and inflammation on the anti-TNFα response. We found a significant association between the SNP in TNFα promoter (-308G>A) and clinical remission without steroids in patients on infliximab therapy. Additionally, a potential connection between HLA-DQA1*05 genetic variant carriers and a higher risk of anti-TNFα immunogenicity emerged.

Exosomal miR-103a-3p from Crohn's Creeping Fat-Derived Adipose-Derived Stem Cells Contributes to Intestinal Fibrosis by Targeting TGFBR3 and Activating Fibroblasts

BACKGROUND AND AIMS

Mesenteric adipose tissue hypertrophy is a hallmark of Crohn's disease [CD], and creeping fat [CF] is unique to CD. Adipose-derived stem cells [ASCs] from inflammatory tissue exhibited altered biological functions. The role of ASCs isolated from CF in intestinal fibrosis and the potential mechanism remain unclear.

METHODS

ASCs were isolated from CF [CF-ASCs] and disease-unaffected mesenteric adipose tissue [Ctrl-ASCs] of patients with CD. A series of in vitro and in vivo experiments were conducted to study the effects of exosomes from CF-ASCs [CF-Exos] on intestinal fibrosis and fibroblast activation. A micro-RNA microarray analysis was performed. Western blot, luciferase assay and immunofluorescence were performed to further detect the underlying mechanisms.

RESULTS

The results indicated that CF-Exos promoted intestinal fibrosis by activating fibroblasts in a dose-dependent manner. They continuously promoted progression of intestinal fibrosis even after dextran sulphate sodium withdrawal. Further analysis showed that exosomal miR-103a-3p was enriched in CF-Exos and participated in exosome-mediated fibroblast activation. TGFBR3 was identified as a target gene of miR-103a-3p. Mechanistically, CF-ASCs released exosomal miR-103a-3p and promoted fibroblast activation by targeting TGFBR3 and promoting Smad2/3 phosphorylation. We also found that the expression of miR-103a-3p in diseased intestine was positively associated with the degree of CF and fibrosis score.

CONCLUSION

Our findings show that exosomal miR-103a-3p from CF-ASCs promotes intestinal fibrosis by activating fibroblasts via TGFBR3 targeting, suggesting that CF-ASCs are potential therapeutic targets for intestinal fibrosis in CD.

Individualized antibiotic dosage regimens for patients with augmented renal clearance

Objectives: Augmented renal clearance (ARC) is a state of enhanced renal function commonly observed in 30%-65% of critically ill patients despite normal serum creatinine levels. Using unadjusted standard dosing regimens of renally eliminated drugs in ARC patients often leads to subtherapeutic concentrations, poor clinical outcomes, and the emergence of multidrug-resistant bacteria. We summarized pharmaceutical, pharmacokinetic, and pharmacodynamic research on the definition, underlying mechanisms, and risk factors of ARC to guide individualized dosing of antibiotics and various strategies for optimizing outcomes. Methods: We searched for articles between 2010 and 2022 in the MEDLINE database about ARC patients and antibiotics and further provided individualized antibiotic dosage regimens for patients with ARC. Results: 25 antibiotic dosage regimens for patients with ARC and various strategies for optimization of outcomes, such as extended infusion time, continuous infusion, increased dosage, and combination regimens, were summarized according to previous research. Conclusion: ARC patients, especially critically ill patients, need to make individualized adjustments to antibiotics, including dose, frequency, and method of administration. Further comprehensive research is required to determine ARC staging, expand the range of recommended antibiotics, and establish individualized dosing guidelines for ARC patients.

Revolutionizing Precision Medicine: Exploring Wearable Sensors for Therapeutic Drug Monitoring and Personalized Therapy

Precision medicine, particularly therapeutic drug monitoring (TDM), is essential for optimizing drug dosage and minimizing toxicity. However, current TDM methods have limitations, including the need for skilled operators, patient discomfort, and the inability to monitor dynamic drug level changes. In recent years, wearable sensors have emerged as a promising solution for drug monitoring. These sensors offer real-time and continuous measurement of drug concentrations in biofluids, enabling personalized medicine and reducing the risk of toxicity. This review provides an overview of drugs detectable by wearable sensors and explores biosensing technologies that can enable drug monitoring in the future. It presents a comparative analysis of multiple biosensing technologies and evaluates their strengths and limitations for integration into wearable detection systems. The promising capabilities of wearable sensors for real-time and continuous drug monitoring offer revolutionary advancements in diagnostic tools, supporting personalized medicine and optimal therapeutic effects. Wearable sensors are poised to become essential components of healthcare systems, catering to the diverse needs of patients and reducing healthcare costs.

Therapeutic Drug Monitoring of Anti-TNFα Inhibitors: A Matter of Cut-Off Ranges

Therapeutic drug monitoring (TDM) is a useful tool for optimising the use of anti-TNFα inhibitors in patients with inflammatory bowel diseases (IBDs). Recently, point-of-care methods for the quantification of drug levels and anti-drug antibodies (ADAs) have been developed to overcome the limitations of conventional enzyme-linked immunoabsorbent assays (ELISAs). Here, we evaluated the performance, interchangeability, and agreement between an automated ELISA-based immunoassay (CHORUS Promonitor) and the lateral flow assay (RIDA^®QUICK) for the quantification of infliximab (IFX, n = 65) and adalimumab (ADM, n = 58) plasma levels in IBD patients. Thirty-two samples for IFX and twenty-three samples for ADM that tested positively for the presence of ADAs were also used. Overall, data analysis showed a good agreement of ADM trough concentrations (R² = 0.75) between the two assays as well as for ADA measurement (K > 0.8). However, IFX levels highlighted a weak correlation (R² = 0.58) between the two kits, with the RIDA^®QUICK assay overestimating IFX plasma values by 30% when compared to the CHORUS Promonitor kit. Results from this study show that the two assays are not quantitatively and qualitatively interchangeable due to substantial discrepancies in some results. Accordingly, the same assay should be used for the longitudinal follow-up of IBD patients.

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.

Therapeutic drug monitoring of disease-modifying antirheumatic drugs in circulating leukocytes in immune-mediated inflammatory diseases

The treatment of immune-mediated inflammatory diseases (IMIDs) is one of the main challenges of modern medicine. Although a number of disease-modifying antirheumatic drugs (DMARDs) are available, there is wide variability in clinical response to treatment among individuals. Therapeutic drug monitoring (TDM) has been proposed to optimize treatment; however, some patients still experience unsatisfactory outcomes, although the blood concentrations of drugs in these patients remain in the therapeutic range. One possible reason for this is that the conventional samples (e.g., whole blood or plasma) used in TDM may not accurately reflect drug concentrations or concentrations of their metabolites at the target site. Hence, more refined TDM approaches to guide clinical decisions related to dose optimization are necessary. Circulating leukocytes or white blood cells have a critical role in driving the inflammatory process. They are recruited to the site of injury, infection and inflammation, and the main target of small molecule DMARDs is within immune cells. Given this, assaying drug concentrations in leukocytes has been proposed to be of possible relevance to the interpretation of outcomes. This review focuses on the clinical implications and challenges of drug monitoring of DMARDs in peripheral blood leukocytes from therapeutic or toxicological perspectives in IMIDs.

Personalizing therapy selection in inflammatory bowel disease

INTRODUCTION

Inflammatory bowel disease (IBD) is a complex disease, caused by aberrant immune responses to environmental stimuli where genetic, metabolomic, and environmental variables interact to cause mucosal inflammation. This review sheds light on the different drug and patient related factors that affect personalization of biologics in IBD treatment.

AREAS COVERED

We utilized the online research database PubMed to carry out literature search pertaining to therapies in IBD. We incorporated a combination of primary literature as well as review articles and meta-analyses in writing this clinical review. In this paper, we discuss the mechanisms of action for different biologics, the genotype and phenotype of patients, and pharmacokinetics/pharmacodynamics of drugs, as factors that influence response rates. We also touch upon the role of artificial intelligence in treatment personalization.

EXPERT OPINION

The future of IBD therapeutics is one of precision medicine, based on the identification of aberrant signaling pathways unique to individual patients as well as exploring the exposome, diet, viruses, and epithelial cell dysfunction as part of disease pathogenesis. We need global cooperation for pragmatic study designs as well as equitable access to machine learning/artificial intelligence technology to reach the unfulfilled potential of IBD care.

Personalized Dosing of Infliximab in Patients With Inflammatory Bowel Disease Using a Bayesian Approach: A Next Step in Therapeutic Drug Monitoring

Although biological agents have revolutionized the management of inflammatory bowel diseases (IBDs), a significant proportion of patients show primary non-response or develop secondary loss of response. Therapeutic drug monitoring (TDM) is advocated to maintain the efficacy of biologic agents. Reactive TDM can rationalize the management of primary non-response and secondary loss of response and has shown to be more cost-effective compared with empiric dose escalation. Proactive TDM is shown to increase clinical remission and the durability of the response to a biologic agent. However, the efficacy of proactive and reactive TDM has been questioned in recent studies and meta-analyses. Hence, we need a different approach to TDM, which addresses inflammatory burden, the individual patient, and disease factors. Bayesian approaches, which use population pharmacokinetic models, enable clinicians to make better use of TDM for dose adjustment. With rapid improvement in computer technology, these Bayesian model-based software packages are now available for clinical use. Bayesian dashboard systems allow clinicians to apply model-based dosing to understand an individual's pharmacokinetics and achieve a target serum drug concentration. The model is updated using previously measured drug concentrations and relevant patient factors, such as body weight, C-reactive protein, and serum albumin concentration, to maintain effective drug concentrations in the serum. Initial studies have found utility for the Bayesian approach in induction and maintenance, in adult and pediatric patients, in clinical trials, and in real-life situations for patients with IBD treated with infliximab. This needs confirmation in larger studies. This article reviews the Bayesian approach to therapeutic drug monitoring in IBD.

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.

90K/Mac-2 BP Is a New Predictive Biomarker of Response to Infliximab Therapy in IBD Patients

Inflammatory bowel diseases (IBD), comprising Crohn's disease (CD) and Ulcerative Colitis (UC), are multifactorial disorders characterized by a chronic inflammatory status with the secretion of cytokines and immune mediators. Biologic drugs targeting pro-inflammatory cytokines, such as infliximab, are broadly used in the treatment of IBD patients, but some patients lose responsiveness after an initial success. The research into new biomarkers is crucial for advancing personalized therapies and monitoring the response to biologics. The aim of this single center, observational study is to analyze the relationship between serum levels of 90K/Mac-2 BP and the response to infliximab, in a cohort of 48 IBD patients (30 CD and 18 UC), enrolled from February 2017 to December 2018. In our IBD cohort, high 90K serum levels were found at baseline in patients who then developed anti-infliximab antibodies at the fifth infusion (22 weeks after the first), becoming non-responders (9.76 ± 4.65 µg/mL compared to 6.53 ± 3.29 µg/mL in responder patients, p = 0.005). This difference was significant in the total cohort and in CD, but not significant in UC. We then analyzed the relationship between serum levels of 90K, C-reactive protein (CRP), and Fecal calprotectin. A significant positive correlation was found at baseline between 90K and CRP, the most common serum inflammation marker (R = 0.42, p = 0.0032). We concluded that circulating 90K could be considered a new non-invasive biomarker for monitoring the response to infliximab. Furthermore, 90K serum level determination, before the first infliximab infusion, in association with other inflammatory markers such as CRP, could assist in the choice of biologics for the treatment of IBD patients, thereby obviating the need for a drug switch due to loss of response, and so improving clinical practice and patient care.

Exploring human biology with N-of-1 clinical trials

Studies on humans that exploit contemporary data-intensive, high-throughput 'omic' assay technologies, such as genomics, transcriptomics, proteomics and metabolomics, have unequivocally revealed that humans differ greatly at the molecular level. These differences, which are compounded by each individual's distinct behavioral and environmental exposures, impact individual responses to health interventions such as diet and drugs. Questions about the best way to tailor health interventions to individuals based on their nuanced genomic, physiologic, behavioral, etc. profiles have motivated the current emphasis on 'precision' medicine. This review's purpose is to describe how the design and execution of N-of-1 (or personalized) multivariate clinical trials can advance the field. Such trials focus on individual responses to health interventions from a whole-person perspective, leverage emerging health monitoring technologies, and can be used to address the most relevant questions in the precision medicine era. This includes how to validate biomarkers that may indicate appropriate activity of an intervention as well as how to identify likely beneficial interventions for an individual. We also argue that multivariate N-of-1 and aggregated N-of-1 trials are ideal vehicles for advancing biomedical and translational science in the precision medicine era since the insights gained from them can not only shed light on how to treat or prevent diseases generally, but also provide insight into how to provide real-time care to the very individuals who are seeking attention for their health concerns in the first place.

Optimized Infliximab Induction Predicts Better Long-Term Clinical and Biomarker Outcomes Compared to Standard Induction Dosing

OBJECTIVES

To evaluate the efficacy of standard and optimized infliximab induction dosing in attaining corticosteroid (CS) free clinical remission at week 52 and the effect that post-induction trough levels have on long-term outcome.

METHODS

Inflammatory bowel disease (IBD) patients ≤18 years commenced on infliximab between August 1, 2016, and August 1, 2018, from Vancouver, Canada, and Glasgow, Scotland, were included. The Glasgow cohort followed standard induction while the Vancouver cohort undertook induction optimization based on clinical, biomarker, and proactive infliximab trough levels. Baseline characteristics and laboratory values were documented.

RESULTS

In total, 140 children were included [median age 14.1 years (interquartile range (IQR) 12.0-16.0)]; 54% male. CS-free clinical remission at week 52 was higher in the optimized group compared to the standard cohort [65/78 (83%) vs. 32/62 (52%), P < 0.001]. Combined CS-free clinical and biomarker remission (CRP < 5 mg/L) was also higher in the optimized compared to the standard cohort [65/78 (83%) vs 25/62 (40%), P < 0.001]. The median post-induction trough level was higher in children who were in CS-free clinical remission at week 52 [3.6 mg/L (1.5-7.1)] vs. those who were not [2.0 mg/L (0.8-4.1), P = 0.04]. The odds of attaining a therapeutic post-induction trough level were almost 4-fold higher in the optimized group than the standard cohort (OR 3.97, 95% CI: 1.89-8.68, P < 0.001).

CONCLUSIONS

Standard infliximab induction resulted in less favorable long-term outcomes for pediatric IBD patients. Optimizing induction using clinical, biomarker, and proactive trough levels resulted in higher post-induction trough levels and a greater odds of attaining long-term clinical remission.

Proactive Therapeutic Drug Monitoring Versus Conventional Management for Inflammatory Bowel Diseases: A Systematic Review and Meta-Analysis

BACKGROUND & AIMS

Proactive therapeutic drug monitoring (TDM) has been proposed to improve outcomes in patients with inflammatory bowel disease (IBD) treated with tumor necrosis factor (TNF)α antagonists. We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing proactive TDM with conventional management in patients with IBD.

METHODS

We identified RCTs in patients with IBD treated with TNFα antagonists comparing proactive TDM (routine assessments of trough concentration with dose adjustments to maintain predetermined trough concentration, regardless of disease activity) with conventional management (clinically driven dose adjustments). The primary outcome was failure to maintain clinical remission. Certainty of evidence was appraised using Grading of Recommendations, Assessment, Development and Evaluations.

RESULTS

On meta-analysis of 9 RCTs (8 RCTs in adults, and focusing on maintenance phase), there was no significant difference in the risk of failing to maintain clinical remission in patients who underwent proactive TDM (267/709; 38%) vs conventional management (292/696; 42%) (relative risk [RR], 0.96; 95% confidence interval [CI], 0.81-1.13) with moderate heterogeneity (inconsistency index = 36%) (Grading of Recommendations, Assessment, Development and Evaluations; low certainty evidence), with no differences in patients with Crohn's disease (RR, 0.87 ; 95% CI, 0.66-1.15) and ulcerative colitis (RR, 0.88; 95% CI, 0.72-1.07). Disease duration, concomitant immunomodulators, disease activity at baseline, and optimization of therapy before randomization did not modify this association. No differences were observed in risk of developing antidrug antibodies or serious adverse events. Patients in the proactive TDM arm were more likely to undergo dose escalation (RR, 1.56; 95% CI, 1.25-1.94).

CONCLUSIONS

Routine proactive TDM to target biologic concentration to specific thresholds, regardless of disease activity, did not offer clinical benefit in patients with IBD treated with TNFα antagonists in RCTs conducted to date. We cannot exclude the possibility of benefit in disease subtypes and phases of therapy (induction) not represented in these RCT populations.