Performance of Eight Infliximab Population Pharmacokinetic Models in a Cohort of Dutch Children with Inflammatory Bowel Disease.

BACKGROUND AND OBJECTIVE: Efficacy of infliximab in children with inflammatory bowel disease can be enhanced when serum concentrations are measured and further dosing is adjusted to achieve and maintain a target concentration. Use of a population pharmacokinetic model may help to predict an individual's infliximab dose requirement. The aim of this study was to evaluate the predictive performance of available infliximab population pharmacokinetic models in an independent cohort of Dutch children with inflammatory bowel disease. METHODS: In this retrospective study, we used data of 70 children with inflammatory bowel disease (443 infliximab concentrations) to evaluate eight models that focused on infliximab pharmacokinetic models in individuals with inflammatory bowel disease, preferably aged ≤ 18 years. Predictive performance was evaluated with prior predictions (based solely on patient-specific covariates) and posterior predictions (based on covariates and infliximab trough concentrations). Model accuracy and precision were calculated with relative bias and relative root mean square error and we determined the classification accuracy at the trough concentration target of ≥ 5 mg/L. RESULTS: The population pharmacokinetic model by Fasanmade was identified to be most appropriate for the total dataset (relative bias before/after therapeutic drug monitoring: -20.7%/11.2% and relative root mean square error before/after therapeutic drug monitoring: 84.1%/51.6%), although differences between models were small and several were deemed suitable for clinical use. For the Fasanmade model, sensitivity and specificity for maximum posterior predictions for the next infliximab trough concentration to be ≥ 5 mg/L were respectively 83.5% and 80% with an area under the receiver operating characteristic curve of 0.870. CONCLUSIONS: In our paediatric cohort, various models provided acceptable predictive performance, with the Fasanmade model deemed most suitable for clinical use. Model-informed precision dosing can therefore be expected to help to maintain infliximab trough concentrations in the target range.

Infliximab Concentrations during Induction Are Predictive for Endoscopic Remission in Pediatric Patients with Inflammatory Bowel Disease under Combination Therapy.

OBJECTIVES: To study infliximab (IFX) pharmacokinetics in children with inflammatory bowel disease (IBD) during induction therapy to predict outcome and explore if other covariates influenced outcome. STUDY DESIGN: All children with IBD starting IFX therapy (5 mg/kg at weeks 0, 2, 6, and 12) for active luminal disease from May 2017 to May 2019 were included and followed prospectively. Patients were sampled at multiple timepoints during induction (trough concentrations and peak concentration at weeks 0, 2, 6, and 12, and intermediate concentration at weeks 1-4). IFX concentrations and cumulative drug exposure were correlated with outcome at 6 months. Endoscopic remission was defined as Simple Endoscopic Score for Crohn's Disease of <3 or Mayo endoscopic subscore of 0, and deep remission as endoscopic with clinical remission (Pediatric Ulcerative Colitis Activity Index/Pediatric Crohn's Disease Activity Index of <10). RESULTS: There were 252 serum induction concentrations obtained from 32 patients (81% on concomitant thiopurines). Children in endoscopic remission (all in deep remission) at 6 months had significantly higher drug concentrations from week 4 onward. A receiver operating characteristics curve analysis identified IFX trough concentrations at week 12 of ≥5.0 µg/mL and area under the curve at weeks 0-12 of ≥4056.0 µg∗day/mL as the minimal target to achieve endoscopic remission at 6 months (area under the receiver operating characteristics curve, 0.796 [95% CI, 0.62-0.97] and area under the receiver operating characteristics curve, 0.778 [95% CI, 0.61-0.94], respectively). In addition, our findings suggest that proteomic analysis may help to understand IFX response. CONCLUSIONS: Higher IFX exposure during induction therapy in pediatric patients with IBD is associated with significantly better endoscopic and deep remission rates at 6 months. Drug concentrations differentiate remitters from nonremitters from week 4 after induction onward.

Management of inflammatory bowel disease and serum level of infliximab in newborn exposed to anti-TNF therapy during pregnancy: Case report and literature review.

RATIONALE: Heightened inflammatory bowel disease (IBD) activity during pregnancy is associated with higher rates of preterm birth, miscarriage, and low birth weight. Therefore, its adequate treatment is essential, considering the risk-benefit of medication use. Although previous literature has described the management of IBD during pregnancy, few studies have assessed the pharmacokinetics of IBD drugs in the newborn. In this case report, we describe the management of ulcerative colitis during pregnancy and discuss the benefits of checking serum levels of infliximab in newborns exposed to the medication during pregnancy. PATIENT CONCERN: A 37-year-old patient with ulcerative colitis in clinical and endoscopic remission had been undergoing treated with infliximab since 2008. The patient became pregnant in 2018. DIAGNOSIS AND INTERVENTION: Infliximab medication was discontinued at the 29th week of pregnancy. OUTCOMES: The pregnancy was uneventful, and the levels of infliximab in the umbilical cord were >20 µg/dL. Live vaccinations were postponed until the baby was 6 months old, when a new serum drug level proved to be undetectable. LESSONS: Our case suggests that the use of infliximab is safe in pregnancy, and drug discontinuation could be considered from the 24th week of pregnancy onward to reduce placental transfer to the newborn in patients at low risk of relapse. Vaccines with live attenuated organisms should be delayed for at least 6 months or until the serum level of the medication is undetectable.

Single- and Multiple-Dose Pharmacokinetics and Pharmacodynamics of PN-943, a Gastrointestinal-Restricted Oral Peptide Antagonist of α4ß7, in Healthy Volunteers.

PN-943 is an orally stable, gastrointestinal-restricted peptide that binds specifically to α4ß7 integrin on leukocytes, blocking leukocyte trafficking to and activation in the gut, inhibiting colon inflammation and reducing signs and symptoms of active ulcerative colitis. Two pharmacokinetic/pharmacodynamic studies were conducted in healthy volunteers. Study 1 was a first-in-human study with 40 male subjects receiving PN-943, 100 to 1400 mg or placebo, as single doses and 57 male subjects receiving PN-943, 100 to 1000 mg or placebo, as multiple doses. Study 2 was a randomized, crossover study comparing multiple doses of 450-mg PN-943 twice daily as a liquid solution and as an immediate-release tablet in 10 subjects. No subjects discontinued due to treatment-emergent adverse events. Consistent with the gastrointestinal-restricted nature of the peptide, systemic exposure was minimal; there was an approximate dose-proportional increase in area under the plasma concentration-time curve. There was minimal accumulation with once-daily dosing and an absence of time-dependent changes in pharmacokinetics. Administration of PN-943 after a high-fat meal reduced peak plasma concentration and area under the plasma concentration-time curve. There was minimal (<0.1%) urinary excretion of intact drug, and there was a dose-related increase in fecal excretion of intact PN-943. Dose-dependent increases in blood receptor occupancy and reduction in blood receptor expression were observed, supporting target engagement. Twice-daily dosing resulted in sustained receptor occupancy with low plasma fluctuations (143%). PN-943 was generally well tolerated following single and multiple oral doses with low systemic exposure. Twice-daily dosing resulted in sustained pharmacokinetics and pharmacodynamics, supporting further investigation in efficacy studies.

Higher Postinduction Infliximab Concentrations Are Associated With Improved Clinical Outcomes in Fistulizing Crohn's Disease: An ACCENT-II Post Hoc Analysis.

INTRODUCTION: There are only limited data regarding the role of therapeutic drug monitoring in fistulizing Crohn's disease (CD). We investigated the association between both induction and maintenance serum infliximab concentrations and favorable therapeutic outcomes in patients with fistulizing CD. METHODS: This was a post hoc analysis of the ACCENT-II trial evaluating patients with fistulizing CD receiving induction (n = 282) and maintenance infliximab therapy (n = 139). Investigated therapeutic outcomes at both week 14 and week 54 included fistula response, complete fistula response, C-reactive protein (CRP) normalization (≤5 mg/L) in patients with an elevated baseline CRP, and a more stringent outcome of composite remission, defined as combined complete fistula response and CRP normalization. Associations between serum infliximab concentrations and outcomes were assessed by multivariable logistic regression models. RESULTS: Higher week 14 infliximab concentrations were independently associated with week 14 fistula response (odds ratio [OR]: 1.16; 95% confidence interval [CI]: 1.02-1.32; P = 0.019), and composite remission (OR: 2.32; 95% CI: 1.55-3.49; P < 0.001). Higher week 14 infliximab concentrations were also independently associated with week 54 composite remission (OR: 2.05; 95% CI: 1.10-3.82; P = 0.023). Based on receiver operating characteristic curve analysis, week 14 infliximab concentrations thresholds with combined maximal sensitivity and specificity of ≥20.2 µg/mL at week 2, ≥15 µg/mL at week 6, and ≥7.2 µg/mL at week 14 were associated with week 14 composite remission. DISCUSSION: Higher post-induction infliximab concentrations are associated with early and long-term favorable therapeutic outcomes in patients with fistulizing CD.

Optimization of infliximab therapy in inflammatory bowel disease using a dashboard approach-an Indian experience.

PURPOSE: Infliximab (IFX) therapy in inflammatory bowel disease (IBD) is associated with loss of response in half the patients, due to complex pharmacokinetic and immunological factors. Dashboard's Bayesian algorithms use information from model and individual multivariate determinants of IFX concentration and can predict dose and dosing interval. AIM: To compare measured IFX concentrations in our laboratory with values predicted by iDose dashboard system and report its efficacy in managing patients not responding to conventional dosing schedule. METHOD: Clinical history, demographic details, and laboratory findings such as albumin and C-reactive protein (CRP) data of IBD patients (n = 30; median age 23 years (IQR: 14.25 - 33.5)) referred for IFX drug monitoring in our laboratory from November 2017 to November 2019 were entered in iDose software. The IFX concentration predicted by iDose based on this information was compared with that measured in our laboratory. In addition, a prospective dashboard-guided dosing was prescribed in 11 of these 30 patients not responding to conventional dosing and was followed to assess their clinical outcome. RESULT: IFX monitoring in our 30 patients had shown therapeutic concentration in 12, supratherapeutic in 2 and subtherapeutic concentration in 16 patients. The iDose predicted concentration showed concordance in 21 of these 30 patients. Of 11 patients managed with iDose-assisted prospective dosing, 8 achieved clinical remission, 2 showed partial response, and one developed antibodies. CONCLUSION: Retrospective data analysis showed concordance between laboratory measured and iDose-predicted IFX level in 70% of patients. iDose-assisted management achieved clinical remission and cost reduction.

Association Between Vedolizumab Levels, Anti-vedolizumab Antibodies, and Endoscopic Healing Index in a Large Population of Patients with Inflammatory Bowel Diseases.

BACKGROUND: The aim of this study was to assess the relationship between serum vedolizumab (VDZ) concentrations and antibodies to VDZ (ATV) in a large cohort of patients with inflammatory bowel diseases. Furthermore, we evaluated the association between serum VDZ concentrations and a novel serum-based biomarker panel designated as the endoscopic healing index (EHI), developed and validated for identifying mucosal inflammation in patients with Crohn's disease (CD). METHODS: Retrospective study where results from patient samples submitted to a commercial clinical laboratory were included. Serum VDZ and ATV levels were analyzed using a drug-tolerant assay. In CD patients for whom both VDZ and EHI were available, VDZ concentrations were correlated with EHI. serum VDZ threshold analysis was performed using ROC curves, and the serum VDZ concentrations that best differentiated EHI < 20 (previously associated with endoscopic remission) were chosen. RESULTS: A total of 9356 patients were included in the VDZ/ATV analysis. Detectable ATV was observed in 2.9% patients with significantly lower serum VDZ concentrations when compared to those with undetectable ATV [3.9 µg/mL (0-9.0) vs. 11.3 µg/mL (5.9-20.6), p < 0.0001]. Of the patients with serum VDZ result, 287 patients had a concomitant EHI test. An inverse correlation was observed between VDZ concentration and EHI (rho = - 0.20, p < 0.001). A serum VDZ concentration ≥ 15.7 µg/ml was best correlated wi th an EHI < 20 [AUROC: 0.67 (95% CI 0.57-0.77)]. CONCLUSIONS: Incidence of ATVs was low, but significantly associated with lower VDZ levels. A serum VDZ concentration threshold of ≥ 15.7 µg/ml was associated with endoscopic remission as defined by an EHI < 20.

Infliximab Trough Levels Are Not Predictive of Relapse in Patients with IBD in Endoscopic Remission: A Multicenter Cohort Study.

BACKGROUND: Therapeutic drug monitoring (TDM) is important in optimizing use of biologics in inflammatory bowel diseases (IBD). However, the role of proactive TDM during remission remains uncertain. METHODS: This retrospective study included patients receiving infliximab (IFX) therapy at Massachusetts General Hospital or Erasmus University Medical Center. All eligible patients had completed induction phase of IFX and were in clinical and endoscopic remission. Our primary outcome was clinical relapse within 2 years after baseline. Multivariable regression models examined the association between infliximab trough levels during remission and relapse, need for IBD-related surgery or hospitalization. RESULTS: Our study cohort included 110 patients with IBD (72 CD, 38 UC) on IFX maintenance therapy. In total, 12 patients (10.9%) experienced relapse of disease over 2 years. The mean IFX trough level at baseline was 8.0 µg/mL (± 8.6) and did not differ between the institutions. 49.1% of patients had levels < 5 µg/mL and 2.7% had antibodies to infliximab at baseline. There was no difference in the mean IFX trough levels between patients who relapsed (7.5 µg/mL ± 3.7 µg/mL) over 24 months compared to those who did not (8.1 µg/mL ± 7.9 µg/mL, p = 0.815). On multivariable logistic regression analysis, IFX trough levels at baseline were not associated with relapse of disease over 24 months (OR 1.01, 95% CI 0.93-1.09, p = 0.856). CONCLUSION: This retrospective multicenter study provides evidence that IFX trough levels during quiescent disease do not predict relapse over 2 years, suggestive that proactive TDM in this setting is not warranted.

Higher vedolizumab serum levels do not increase the risk of adverse events in patients with inflammatory bowel disease.

Background: Although its mechanism of action may confer a safety benefit, vedolizumab has still been associated with adverse events (AE). We investigated whether inflammatory bowel disease (IBD) patients with higher trough vedolizumab serum levels experienced an increased risk of AEs.Methods: This was a retrospective study of 76 IBD patients with at least one measurement of serum vedolizumab available. Vedolizumab levels ranged from <3.5 mcg/mL to 87.2 mcg/mL (median = 15.8 mcg/mL). The primary outcome was the rate of overall AEs. Secondary outcomes included the rates of infections, dermatologic reactions, infusion reactions, and other AEs. Multivariate logistic regression analysis was performed to evaluate the relationship between serum vedolizumab levels and AEs.Results: 19 patients out of 76 reported AEs. In patients with higher vedolizumab levels, there were 10 AEs reported out of 38 patients, which was not significantly different from the 9 AEs reported in 38 patients with lower vedolizumab levels (26.3% vs. 23.7%, p = .79). After adjustment for potential covariates, IBD patients with higher vedolizumab levels did not have higher odds of an AE than patients with lower levels (OR 0.92, 95% CI 0.30-2.81). Longer duration of therapy had higher odds of AEs, (OR of 1.04 at 95% CI 1.00-1.09, p = .0494 per additional month). None of the other variables were associated with a greater risk of AEs.Conclusions: There does not appear to be an increased risk of adverse events in IBD patients with higher vedolizumab levels, but duration of therapy may increase the risk of AEs.

Interspecies differences on pharmacokinetics of rebamipide following oral administration to rats and dogs.

Rebamipide is used widely in East Asia for the treatment of gastric ulcers, acute gastritis, and exacerbated chronic gastritis. The objective of this study was to investigate the pharmacokinetic (PK) properties of rebamipide following single oral administration in rats and dogs. Eleven rats and dogs received single oral administrations of rebamipide (35 mg/kg and 100 mg, respectively). Blood samples were collected according to the assigned schedule, and the plasma concentration of rebamipide was determined using liquid chromatography-tandem mass spectrometry. A double-peak phenomenon was observed in the PK profile of rebamipide in rats. In contrast, rebamipide showed a conventional PK profile without double peaks in dogs. The half-life of rebamipide in rats (12.85 ± 7.86 h) was longer than that in dogs (5.62 ± 2.24 h), and the apparent total clearance (Clt /F) of rebamipide in rats (3.32 ± 1.18 L/h) was lower than that in dogs (105.01 ± 42.37 L/h). Simple allometric approaches showed that the correlation between body weight and Clt /F (R2 = 0.9287) among rats, dogs, and humans appeared satisfactory. This finding will help not only in understanding the pharmacology of rebamipide but also in establishing a strategy for in vivo evaluation of novel rebamipide formulations.

Infliximab levels and antibodies in IBD-related peripheral arthralgia.

BACKGROUND: Extra-intestinal manifestations (EIM) are common in inflammatory bowel diseases (IBD) and may affect up to 40% of the patients during the course of the disease. Peripheral arthralgia (PA) is by far the most common EIM. To date, TNFα inhibitors are the most established treatment for EIMs in IBD. Infliximab (IFX) trough levels (TL) and anti-IFX antibodies (ATI) are correlated with multiple outcomes in IBD such as clinical response and remission, mucosal healing, fistular healing, and more. So far, a correlation between PA and IFX TL\ATI has not been evaluated. METHODS: This retrospective study included IBD patients followed by the gastroenterology department of Sheba Medical Center. Patients with active PA at onset of IFX treatment were included. IFX TL and ATI were evaluated at week 6, 14, and 26 and correlated with PA persistence. RESULTS: Forty patients (37 Crohn's and 3 ulcerative colitis) with IBD-related PA were included. The overall prevalence of PA was 55% (22/40), 42.5% (17/40), and 55% (22/40) after 6, 14, and 26 weeks, respectively. IFX trough drug levels were not associated with reported PA at week 6 [median, 11.8 µg/ml (IQR 6.6-15.5) vs 10.05 µg/ml (IQR 7.35-12.87), p = 0.56], week 14 [median, 4.7 µg/ml (IQR 2.3-7) vs 3.1 µg/ml (IQR 1.35-7.35), p = 0.55], and week 26 [median, 3 µg/ml (IQR 1.15-5.17) vs 3.4 µg/ml (IQR 0.13-6.75), p = 0.94]. Detectable ATI were significantly more prevalent in patients with PA than in patients without PA at week 26 [11/22 (50%) vs 3/18 (16.7%), p = 0.028]. CONCLUSIONS: In patients with IBD-related PA, ATI are associated with an increased risk of persistence of PA. No direct correlation was demonstrated between IFX TL and persistence of PA.

Population Pharmacokinetics and Pharmacodynamics of Ontamalimab (SHP647), a Fully Human Monoclonal Antibody Against Mucosal Addressin Cell Adhesion Molecule-1 (MAdCAM-1), in Patients With Ulcerative Colitis or Crohn's Disease.

Ontamalimab (SHP647) is a fully human, immunoglobulin G2 , antihuman mucosal addressin cell adhesion molecule-1 (MAdCAM-1) monoclonal antibody being developed for the treatment of ulcerative colitis (UC) and Crohn's disease (CD). A population pharmacokinetic/pharmacodynamic (PK/PD) analysis was conducted using clinical phase 2 study data to evaluate the PK and PD of ontamalimab following subcutaneous administrations of 7.5, 22.5, 75, and 225 mg every 4 weeks in patients with moderate to severe UC or CD. A total of 440 patients with UC (n = 249; 56.6%) or CD (n = 191; 43.4%) were included in the analysis. A 2-compartment model with parallel linear and nonlinear elimination adequately characterized concentration-time profiles of ontamalimab. The apparent clearance and volume of distribution were 0.0127 L/h (0.305 L/day) and 6.53 L, respectively. Apparent clearance and volume of distribution were mainly dependent on baseline albumin and body weight, respectively. No differences in the PK properties of ontamalimab were observed between patients with UC or CD. The presence of antidrug antibodies did not impact the PK of ontamalimab. Nonlinear elimination occurred at very low concentrations and was unlikely to contribute to the elimination half-life under steady-state conditions. A linear PK/PD model described the relationship between ontamalimab and free MAdCAM-1. Minimum concentrations of ontamalimab at steady state following 75 mg every 4 weeks were associated with >95% suppression of circulating free MAdCAM-1. The PK/PD properties characterized support phase 3 testing in UC and CD.

Prediction of treatment failure during infliximab induction therapy in inflammatory bowel disease patients based on pharmacokinetic and pharmacodynamic modeling.

BACKGROUND: In infliximab (IFX) treatment for Crohn's disease (CD) and ulcerative colitis (UC), it is difficult to predict treatment failure during the induction phase. In the present study for optimal IFX treatment, we attempted to estimate serum IFX concentration and clinical response in individual patients during the induction phase to predict the indication of therapeutic effect and the possibility of treatment failure in the maintenance phase. METHODS: We estimated pharmacokinetic and pharmacodynamic (PK/PD) parameters and predicted the serum IFX concentration and clinical response using a PK/PD model and Markov chain Monte Carlo Bayesian analysis method during the induction phase. Then, we determined whether the indication of therapeutic effect between predicted and observed clinical response were matched during the maintenance phase. RESULTS: Data obtained from 15 patients were analyzed. The correlation between predicted and observed values of serum IFX concentration (Pearson product-moment correlation coefficient, 0.700; P < 0.0001, n = 68) and clinical response of CD patients (0.790; P < 0.0001, n = 25) and UC patients (0.702; P = 0.0004, n = 21) were significantly high. The indication of therapeutic effect at the final time point of each patient (from day 115 to day 203) were successfully predicted in 14 of 15 patients (93.3%). CONCLUSIONS: This study presents prediction of serum IFX concentration and clinical response in individual patients during induction therapy, with presumption of the indication of therapeutic effect and the treatment failure in the maintenance phase. Our results show the possibility of optimizing IFX therapy during the induction phase.

Comparison of drug survival between infliximab and adalimumab in inflammatory bowel disease.

Background Conventional therapy of inflammatory bowel disease with traditional immunosuppressant medication is increasingly being replaced by biological agents. However, the response to these biological agents may be lost over time, with discontinuation being a marker of loss of effectiveness. There are few published reports on the treatment drug survival of infliximab and adalimumab in patients with inflammatory bowel disease. Objective This study compared the drug survival of infliximab versus adalimumab as first- and second-line treatments, identified factors associated with drug survival, and described reasons for treatment withdrawal. Setting A pharmacy department of a university hospital in Spain. Method A retrospective single-centre cohort study of all patients with inflammatory bowel disease treated with biological agents between 2008 and 2017 at a regional referral hospital. The primary outcome was drug survival and associated factors during a follow-up of 52 months. Main outcome measure Drug survival of infliximab versus adalimumab. Results One hundred thirty-four patients with inflammatory bowel disease (73.9% Crohn's disease and 26.1% ulcerative colitis) were treated with biological therapy. The overall mean drug survival of first-line treatment with an anti-tumour necrosis factor agent was 18.6 months (SD 14.9), with mean values of 20.2 months (SD 16.6) for adalimumab and 17.1 months (SD 13.1) for infliximab. As a second-line treatment, the drug survival of anti-tumour necrosis factor agents was 17.9 months (SD 15.6), with mean values of 22.9 months (SD 17.1) for adalimumab and 12.5 months (SD 11.7) for infliximab. The difference in time to discontinuation at 52 months of follow-up between the infliximab and adalimumab subgroups, as either first- or second-line treatment, was not statistically significant (p = 0.547 and p = 0.676, respectively). Therapeutic drug monitoring was the only factor associated with greater drug survival in first-line treatment (HR 0.27; 95% confidence interval, CI 0.15-0.50) and second-line treatment (HR 0.26; 95% CI 0.10-0.65). Secondary failure to treatment was the most frequent reason for withdrawal. Conclusion Infliximab and adalimumab showed similar drug survival as first- and second-line anti-tumour necrosis factor treatments. Therapeutic drug monitoring was associated with higher drug survival for both first- and second-line anti-tumour necrosis factor treatments.

Switching From Originator Adalimumab to the Biosimilar SB5 in Patients With Inflammatory Bowel Disease: Short-term Experience From a Single Tertiary Clinical Centre.

BACKGROUND AND AIMS: Patients' perspectives after switching from originator to biosimilar adalimumab have yet to be assessed. We evaluated the efficacy of switching from the originator adalimumab to a biosimilar compound [SB5] in patients with inflammatory bowel disease [IBD]. METHODS: Data on IBD patients who were switched from the originator to biosimilar adalimumab [SB5] at IBD Center ISCARE were analysed. Disease activity was assessed using standard clinical indices (Harvey-Bradshaw index [HBI] for Crohn's disease [CD] and partial Mayo score for ulcerative colitis [UC]), and laboratory parameters (C-reactive protein [CRP] and faecal calprotectin [FC]). Trough levels and anti-drug antibodies were measured. Patients were evaluated 10 weeks [W10] after the switch, and results were compared with the control group of patients on originator compound. RESULTS: A total of 93 patients switched to biosimilar adalimumab were included [CD 86%] and were matched to 93 controls for age, gender, diagnosis, and disease activity. There was no difference in the disease activity in either SWITCH or ORIGINATOR cohorts between Weeks 0 and 10. Similarly, no difference was found between cohorts at both prespecified time points. Moreover, no significant differences in CRP or FC concentrations were seen between W0 and W10 either in the SWITCH, or in the ORIGINATOR cohort [p >0.05]. Adalimumab serum trough levels remained stable after the switch. No new safety signals were detected. CONCLUSIONS: Our study confirmed that switching IBD patients from the originator adalimumab to a biosimilar compound [SB5] does not affect treatment efficacy.

Proactive Infliximab Drug Monitoring Is Superior to Conventional Management in Inflammatory Bowel Disease.

BACKGROUND: Increasing evidence supports the use of reactive therapeutic drug monitoring (TDM) in Crohn's disease (CD) and ulcerative colitis (UC) following secondary loss of response. It is still unknown if proactive TDM can improve clinical outcomes. METHODS: Consecutive patients completing infliximab (IFX) induction therapy were prospectively allocated into a proactive TDM protocol (pTDM). Before the fourth infusion and every 2 infusions, IFX trough levels and antidrug antibodies were measured using a drug-sensitive assay (Theradiag, Lisa Tracker). Treatment was proactively escalated aiming at an IFX trough level between 3 and 7 ug/mL (CD) and 5 and 10 ug/mL (UC). A retrospective cohort treated with IFX but without TDM served as the reference group. End points included the need for surgery, hospitalization, treatment discontinuation, and mucosal healing at 2 years of follow-up. RESULTS: Two hundred five patients were included, 56 in the proactive regimen. Treatment escalation was more common in pTDM patients (76.8% vs 25.5%; P < 0.001), who also required less surgery (8.9% vs 20.8%; P = 0.032) and presented higher rates of mucosal healing (73.2% vs 38.9%; P < 0.0001). Proactive TDM significantly decreased the odds of reaching any unfavorable outcome (odds ratio, 0.358; 95% confidence interval, 0.188-0.683; P = 0.002). CONCLUSIONS: Proactive TDM is associated with fewer surgeries and higher rates of mucosal healing than conventional non-TDM-based management.

Improved Population Pharmacokinetic Model for Predicting Optimized Infliximab Exposure in Pediatric Inflammatory Bowel Disease.

BACKGROUND: Many pediatric patients with inflammatory bowel disease (IBD) lose response to infliximab (IFX) within the first year, and achieving a minimal target IFX trough concentration is associated with higher remission rates and longer durability. Population pharmacokinetic (PK) modeling can predict trough concentrations for individualized dosing. The object of this study was to refine a population PK model that accurately predicts individual IFX exposure during maintenance therapy using longitudinal real-practice data. METHODS: We exported data from the electronic health records of pediatric patients with IBD treated with originator IFX at a single center between January 2011 and March 2017. Subjects were divided into discovery and validation cohorts. A population PK model was built and then validated. RESULTS: We identified 228 pediatric patients with IBD who received IFX and had at least 1 drug concentration measured, including 135 and 93 patients in the discovery and validation cohorts, respectively. Weight, albumin, antibodies to IFX (ATI) detected by a drug-tolerant assay, and erythrocyte sedimentation rate (ESR) were identified as covariates significantly associated with IFX clearance and incorporated into the model. The model exhibited high accuracy for predicting target IFX trough concentrations with an area under the receiver operating characteristic curve (AUROC) of 0.86 (95% confidence interval [CI], 0.81-0.91) for population-based predictions without prior drug-level input. Accuracy increased further for individual-based predictions when prior drug levels were known, with an AUROC of 0.93 (95% CI, 0.90-0.97). CONCLUSIONS: A population PK model utilizing weight, albumin, ordinal drug-tolerant ATI, and ESR accurately predicts IFX trough concentrations during maintenance therapy in real-practice pediatric patients with IBD. This model, which incorporates dynamic clinical information, could be used for individualized dosing decisions to increase response durability.

Proactive Vs Reactive Therapeutic Drug Monitoring of Infliximab in Crohn's Disease: A Cost-Effectiveness Analysis in a Simulated Cohort.

BACKGROUND: Therapeutic drug monitoring (TDM) is increasingly performed for Infliximab (IFX) in patients with Crohn's disease (CD). Reactive TDM is a cost-effective strategy to empiric IFX dose escalation. The cost-effectiveness of proactive TDM is unknown. The aim of this study is to assess the cost-effectiveness of proactive vs reactive TDM in a simulated population of CD patients on IFX. METHODS: We developed a stochastic simulation model of CD patients on IFX and evaluated the expected health costs and outcomes of a proactive TDM strategy compared with a reactive strategy. The proactive strategy measured IFX concentration and antibody status every 6 months, or at the time of a flare, and dosed IFX to a therapeutic window. The reactive strategy only did so at the time of a flare. RESULTS: The proactive strategy led to fewer flares than the reactive strategy. More patients stayed on IFX in the proactive vs reactive strategy (63.4% vs 58.8% at year 5). From a health sector perspective, a proactive strategy was marginally cost-effective compared with a reactive strategy (incremental cost-effectiveness ratio of $146,494 per quality-adjusted life year), assuming a 40% of the wholesale price of IFX. The results were most sensitive to risk of flaring with a low IFX concentration and the cost of IFX. CONCLUSIONS: Assuming 40% of the average wholesale acquisition cost of biologic therapies, proactive TDM for IFX is marginally cost-effective compared with a reactive TDM strategy. As the cost of infliximab decreases, a proactive monitoring strategy is more cost-effective.