Serum Infliximab Concentrations Research Articles

Subcutaneous versus intravenous infliximab therapy - a real-world study: toward higher drug concentrations.

Recently, a formula of subcutaneous infliximab (SC-IFX) has been approved for inflammatory bowel disease (IBD), demonstrating a better pharmacokinetic and immunogenic profiles, compared to intravenous infliximab (IV-IFX), with similar efficacy and safety. The aim of this study is to evaluate the clinical, biochemical, and pharmacological outcomes of IBD patients in clinical remission, who switched from IV-IFX to SC-IFX, with a follow-up period of 6 months. Retrospective cohort study, including IBD patients in clinical remission, previously medicated with IV-IFX, who switched to SC-IFX 120 mg every other week. Biochemical parameters were evaluated before the switch and 6 months after, namely infliximab serum concentrations, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and fecal calprotectin. Included 41 patients in clinical remission, 32 with Crohn's disease (78.0%) and 9 with ulcerative colitis (22.0%). All patients maintained clinical remission during the 6 months after the switch, with a treatment persistence rate of 100%, and no patients requiring corticosteroid therapy, switching back to IV-IFX, or IBD-related hospitalization. The mean infliximab serum concentrations were significantly higher after 6 months of SC-IFX (17.3 ± 6.6 vs. 9.1 ± 5.5 µg/ml, P < 0.001). However, there were no differences between values of ESR, CRP, and fecal calprotectin, before and after the switch ( P = 0.791, P = 0.246, and P = 0.639). Additionally, none of the patients developed antibodies to infliximab. Switching from IV-IFX to SC-IFX in IBD patients in clinical remission is effective and leads to higher infliximab serum concentrations, regardless of the combination with immunomodulatory therapy.

Subcutaneous infliximab in Crohn’s disease patients with previous immunogenic failure of intravenous infliximab

PurposeImmunogenicity is a major reason for secondary loss of response to infliximab (IFX). Recent work suggested potentially lower immunogenicity of subcutaneous (SC) compared to intravenous (IV) IFX. However, it is unknown whether re-exposure to IFX SC after secondary loss of response and immunogenicity to its intravenous formulation is safe and effective.MethodsIn a retrospective cohort study conducted at two medical centers, patients with clinically (Harvey-Bradshaw Index ≥ 5) and/or biochemically (fecal calprotectin > 250 µg/g) active Crohn’s disease (CD) and previous immunogenic failure of IFX IV underwent exposure to IFX SC. Harvey-Bradshaw Index, fecal calprotectin, IFX serum concentration, and anti-drug antibodies were assessed until month 12.ResultsTwenty CD patients were included. The majority of patients (90%) had previous treatment with three or more biologics. Fifteen (75%) and ten (50%) of 20 patients continued IFX SC treatment until months 6 and 12, respectively. No immediate hypersensitivity reactions were observed. Two patients discontinued IFX SC treatment because of delayed hypersensitivity at week 2 and week 4. IFX serum concentrations increased from baseline to month 12, while anti-drug antibody levels decreased. Combined clinical and biochemical remission at month 12 was observed in seven of 20 patients (35%).ConclusionSubcutaneous infliximab treatment of Crohn’s disease patients with previous immunogenic failure of intravenous infliximab was well tolerated and effective in a cohort of patients with refractory Crohn’s disease.

Therapeutic Drug Monitoring of Infliximab and Adalimumab through Concentration and Anti-Drug Antibodies Assessment; Comparison of Sanquin Diagnostics and Theradiag Assays.

Therapeutic drug monitoring of biological Tumor Necrosis Factor (TNF)-alpha inhibitors is of critical importance. In this study, the performance of practically advantageous chemiluminescent immunoassays of Theradiag, assessing Infliximab and Adalimumab serum concentrations and anti-drug antibodies (ADA) against these biologics, were compared to the Enzyme-Linked Immuno-Sorbent Assays (ELISAs) from Sanquin Diagnostics. Leftover serum samples (n = 80 for each parameter) from patients treated with Infliximab or Adalimumab were collected. Correlation and agreement analyses for serum concentration and ADAs, respectively, were performed. Both Theradiag ADA assays, an assay targeting both free and bound ADAs and an assay targeting solely free ADAs, were investigated and compared to the Sanquin Diagnostics ADA assay, targeting both free and bound ADAs. Strong positive correlations were observed between the biologic concentration assessment of Infliximab (Spearman's Rho = 0.91) and Adalimumab (Spearman's Rho = 0.94). However, there appeared to be significant bias in the Theradiag assay when compared to Sanquin (Infliximab median (Confidence Interval (CI)) = 2.1 (1.7-2.6) µg/mL; Adalimumab median (CI) = 0.8 (0.5-0.9) µg/mL). Agreement analyses showed moderate to good agreement for the Theradiag and Sanquin Diagnostics ADA assays, when detecting both free and bound ADAs, for Infliximab (Cohen's k = 0.717) and Adalimumab (Cohen's k = 0.802). In contrast, the Theradiag ADA assay detecting solely free ADAs had zero to poor agreement for Infliximab (Cohen's k = 0.458) and Adalimumab (Cohen's k = 0.119), respectively. This study demonstrated strong correlations and good agreement between the Theradiag and Sanquin Diagnostics assays measuring Infliximab and Adalimumab serum concentrations and ADAs, both free and bound, against these biologics. Discordance analyses showed significantly decreased drug concentrations in the solely free assays, indicating that the combined detection of free and bound ADAs better aligns with drug levels.

No Correlation between Anti-drug Antibodies and Therapeutic Response in Tunisian Patients with Chronic Inflammatory Diseases Treated by TNF Blockers.

Tumor necrosis factor alpha (TNF alpha) blockers such as infliximab (IFX) and adalimumab (ADA) had significantly changed the course of inflammatory diseases such as rheumatoid arthritis (RA), spondyloarthritis (SpA) and Crohn's disease (CD). However, about 30% of patients do not respond to these treatments. This lack of response may be due to the formation of antibodies against these drugs (anti-drug antibodies: ADAbs). The aim of this study was to determine the prevalence of ADAbs against IFX and ADA, and the trough serum concentration of IFX and ADA in RA, SpA or CD patients and to assess their impact on the therapeutic response. A cross sectional, multi-centric study was conducted, including patients with RA, SpA or CD treated with IFX or ADA as a first biotherapy for at least 6 months. ADAbs and trough levels were measured by an Enzyme Linked Immunosorbent assay (ELISA). 197 patients were included (57 RA, 73 SpA and 67 CD). ADAbs were positive in 40% of cases for IFX and 25% for ADA. They were positive in 40% of SpA, 35% of RA, and 21% of CD. The presence of ADAbs was inversely correlated to the trough levels of IFX and ADA during RA (p = 0.01 and p < 0.0001), SpA (p < 0.01 and p < 0.0001) and CD (p = 0.001 and p = 0.04). For all pathologies, the presence of ADAbs was not correlated with disease activity. Concomitant methotrexate significantly reduced immunogenicity. In our study, the presence of ADAb and low trough levels seem to not affect the therapeutic response in patients on TNF alpha antagonists. Other tracks more than immunogenicity should be investigated to explain the loss of response to these biotherapies.

Infliximab serum concentrations in luminal Crohn's disease and its relationship with disease activity: A multicentric cross-sectional study

ObjectivesIn Latin America, experience with monitoring serum Infliximab (IFX) concentrations is scarce. Our study aimed to compare IFX serum concentrations between patients with active disease or in remission. Patients and methodsA cross-sectional study was performed in patients with luminal Crohn's disease (CD) during maintenance treatment with IFX. Patients were classified as in remission or disease activity according to clinical scores and endoscopic, radiological, and laboratory markers. A comparison of IFX trough levels between the two groups was performed. Results80 CD patients were included [41 (51%) in remission and 39 (49%) with active disease]. In the analysis of general disease activity, the median serum levels of IFX in patients with remission and with active CD were 5.63 [0.03–14.40] vs. 3.84 [0.03–14.40] (p=0.287). Furthermore, there was no difference in serum IFX concentrations in endoscopic, radiological, and laboratory activities. Only in the clinical evaluation there was a significant difference in the median serum IFX levels between patients in remission and disease activity, 5.63 [0.03–14.40] vs. 2.14 [0.32–10.54] (p=0.042). ConclusionsIFX serum concentrations during maintenance treatment were similar in patients with luminal CD in remission and general, endoscopic, radiological, and laboratory disease activity. Patients with clinically active disease had lower IFX concentrations than patients in remission.

Infliximab serum concentrations and disease activity in perianal fistulizing Crohn's disease: a cross-sectional study.

Several studies associate the presence of higher serum concentrations of infliximab (IFX) with fistula healing in perianal Crohn's disease (CD). This study aimed to evaluate serum IFX concentrations in patients with perianal fistulizing CD (PFCD) in the presence or absence of general, clinical, and radiological activities. This was a cross-sectional study in patients with PFCD during maintenance treatment with IFX from two centers. Serum IFX concentrations were measured before their next infusion and anal fistulas were evaluated by clinical examination and magnetic resonance imaging (MRI), whenever possible, performed 90days before or after serum collection. According to clinical scores, radiological activity, and disease markers, patients were classified as in remission or active disease.Mean serum IFX concentrations were compared between the groups. Thirty-eight patients with PFCD were included. Demographic characteristics were similar in patients with remission or active disease. The overall mean serum IFX concentration of the entire sample (n = 38) was 5.21 ± 4.75 μg/mL (median 3.63; IQR 1.44-8.82). Serum IFX levels were 6.25 ± 5.34 μg/mL (median 3.62; IQR 1.95-11.03) in the 23 (60.5%) patients in remission and 3.63 ± 3.24 μg/mL (median 3.63; IQR 1.32-6.43; p = 0.226) in the 15 (39 .5%) who presented active disease. When evaluating general, clinical, and radiological activity of PFCD, and deep remission in isolation, no statistical difference between the groups was observed (p = 0.226, p = 0.418, p = 0.126, and p = 0.232, respectively). The 13 (34.2%) patients with an optimized dose of IFX had significantly higher serum concentrations than the remaining 25 (65.8%) with a standard dose: 8.33 ± 4.41 μg/mL (median 8.36; IQR 3.82-11.20) vs. 3.59 ± 4.13 μg/mL (median 1.97; IQR 1.18-3.85)-p = 0.002. Patients in remission and with an optimized IFX dose had significantly higher serum IFX concentrations than those with a standard dose (p = 0.006), whereas no significant difference was observed among those with active disease (p = 0.083). There were no differences in IFX serum concentrations in patients with clinical or radiological active PFCD as compared with those in remission. Patients with an optimized IFX dose had significantly higher serum concentrations than those with a standard dose. Patients in remission and with an optimized IFX dose had significantly higher serum concentrations than those with a standard dose.

Antibiotics influence the risk of anti-drug antibody formation during anti-TNF therapy in Chinese inflammatory bowel disease patients.

Aims: The formation of anti-drug antibodies (ADAs) during anti-tumor necrosis factor (anti-TNF) therapy is reported to lead to reducing serum drug levels, which may bring about a loss of response to treatment. Previous research has suggested an association between specific antibiotic classes and ADA formation during anti-TNF therapy. However, there are few studies specifically examining this association in Chinese inflammatory bowel disease (IBD) patients. Therefore, our study aimed to evaluate the possible effect of antibiotic use on ADA formation to anti-TNF therapy in Chinese patients with IBD. Methods: A total of 166 patients with IBD, including 149 with Crohn's disease (CD) and 17 with ulcerative colitis (UC), were included in this retrospective analysis. These patients were initially treated with anti-TNF therapy (infliximab or adalimumab) after January 2018 and reviewed with available ADA levels before October 2023. After univariable analysis of all the variables, a multivariate Cox proportional hazards model was used to assess the association between antibiotic use and ADA development. Results: Among 166 IBD patients treated with infliximab (108/166, 65.1%) or adalimumab (58/166, 34.9%), 31 patients (18.7%) were measured as positive ADA levels. Cox proportional hazard model demonstrated an increased risk of ADA formation in IBD patients who used β-lactam-β-lactamase inhibitor combinations (BL-BLIs) (HR = 5.143, 95%CI 1.136-23.270, p = 0.033), or nitroimidazoles (HR = 4.635, 95%CI 1.641-13.089, p = 0.004) during 12months before the ADA test. On the contrary, a reduced risk was noted in patients treated with fluoroquinolones (HR = 0.258, 95% CI 0.072-0.924, p = 0.037). Moreover, the median serum infliximab or adalimumab concentration in patients with positive ADA levels was significantly lower than that in patients with negative ADA levels (infliximab: 0.30 vs. 1.85μg/mL, p < 0.0001; adalimumab: 0.45 vs. 7.55μg/mL, p = 0.0121). Conclusion: ADA development is associated with various antibiotic classes. BL-BLIs and nitroimidazoles might increase the risk of ADA formation during anti-TNF therapy in Chinese IBD patients, while the treatment with fluoroquinolones could probably reduce such risk. There were certain limitations in the retrospective analysis of the study, therefore, the results are just for reference, and other studies are needed to further confirm our findings.

The Effect of Polymorphisms and Other Biomarkers on Infliximab Exposure in Paediatric Inflammatory Bowel Disease: Development of a Population Pharmacokinetic Model.

Therapeutic drug monitoring (TDM) of infliximab has been shown to be a effective strategy for inflammatory bowel disease (IBD). Population pharmacokinetic (PopPK) modeling can predict trough concentrations for individualized dosing. The aim of this study was to develop a PopPK model of infliximab in a paediatric population with IBD, assessing the effect of single nucleotide polymorphisms (SNPs) and other biomarkers on infliximab clearance. This observational and ambispective single-centre study was conducted in paediatric patients with IBD treated with infliximab between July 2016 and July 2022 in the Paediatric Gastroenterology Service of the Hospital Universitari Vall d'Hebron (HUVH) (Spain). Demographic, clinical, and analytical variables were collected. Twenty SNPs potentially associated with variations in the response to infliximab plasma concentrations were analysed. infliximab serum concentrations and antibodies to infliximab (ATI) were determined by ELISA. PopPK modelling was performed using nonlinear mixed-effects analysis (NONMEM). Thirty patients (21 males) were included. The median age (range) at the start of infliximab treatment was 13 years (16 months to 16 years). A total of 190 samples were obtained for model development (49 [25.8%] during the induction phase). The pharmacokinetics (PK) of infliximab were described using a two-compartment model. Weight, erythrocyte sedimentation rate (ESR), faecal calprotectin (FC), and the SNP rs1048610 (ADAM17) showed statistical significance for clearance (CL), and albumin for inter-compartmental clearance (Q). Estimates of CL1 (genotype 1-AA), CL2 (genotype 2-AG), CL3 (genotype 3-GG), Q, Vc, and Vp (central and peripheral distribution volumes) were 0.0066L/h/46.4kg, 0.0055L/h/46.4kg, 0.0081L/h/46.4kg, 0.0029L/h/46.4kg, 0.6750L/46.4kg, and 1.19L/46.4kg, respectively. The interindividual variability (IIV) estimates for clearance, Vc, and Vp were 19.33, 16.42, and 36.02%, respectively. A popPK model utilising weight, albumin, FC, ESR, and the SNP rs1048610 accurately predicted infliximab trough concentrations in children with IBD.

EFFICACY, SAFETY AND IMMUNOGENICITY OF SUBCUTANEOUS INFLIXIMAB (CT-P13 SC) MONOTHERAPY VERSUS COMBINATION THERAPY WITH IMMUNOSUPPRESSANTS – POST HOC ANALYSIS OF LIBERTY-CD AND LIBERTY-UC STUDY

Abstract INTRODUCTION CT-P13 subcutaneous (SC) infliximab formulation demonstrated superiority over placebo in maintenance therapy in Crohn's disease (CD) and Ulcerative Colitis (UC) patients in two parallel 54 weeks studies (LIBERTY-CD and LIBERTY-UC). We performed a post-hoc subgroup analysis comparing patients treated with CT-P13 SC with and without combination immunosuppressants (IS) at baseline in CD and UC. AIMS &amp; METHODS Patients with moderately to severely active CD and UC who responded at W10 to CT-P13 intravenous infliximab 5mg/kg (Weeks 0, 2 and 6) were randomized (2:1) to receive CT-P13 SC 120 mg (CT-P13 SC) or placebo every 2 weeks until W54 as maintenance therapy. IS (azathioprine [AZA], 6-mercaptopurine [6-MP], or methotrexate [MTX]) were allowed if patients maintained stable doses at least 8 weeks prior to W0, and stable doses were maintained up to W54. RESULTS 231 CD and 294 UC patients were randomized to receive CT-P13 SC maintenance therapy. Among them, 71 (30.7%) and 65 (22.1%) patients received CT-P13 SC with IS in CD and UC, respectively (In CD; 63, 4 and 4 patients of AZA, 6-MP, MTX, respectively, In UC; 63, 2 and 0 patients of AZA, 6-MP, MTX, respectively). There were no meaningful differences in efficacy outcomes at Week 54 by CT-P13 concentration tertiles at Week 54 between monotherapy and combination therapy groups in both studies (Table 1). In combined analysis of CD and UC patients, no statistically significant differences were seen in safety profile between monotherapy and combination therapy groups in the maintenance period except for infection rate (Table 2). In combined analysis of CD and UC patients, rate of anti-drug antibody [ADA] positive conversion up to W54 was statistically lower in combination therapy group (70.2% monotherapy vs 47.8% combination therapy [p&amp;lt;0.0001]). CONCLUSION No meaningful differences in efficacy outcomes at W54 were observed between monotherapy and combination therapy of CT-P13 SC in CD and UC patients. Concomitant IS use was associated with less ADA formation, whereas more infections are seen for combination therapy during maintenance period in CD and UC patients. The overall safety profile during maintenance period was otherwise comparable between monotherapy and combination therapy in CD and UC patients. This post-hoc analysis suggests limited benefit of concomitant IS with CT-P13 SC but a higher infection risk. Notably, patients were not randomized according to IS use nor were the studies ‘powered’ to demonstrate differences. Proportion of patients achieving efficacy outcomes at W54 by tertile of Serum concentrations of Infliximab (ng/mL) at W54 (Pharmacokinetic population) Safety results in maintenance period (Safety population)

P767 Pharmacokinetics of subcutaneous infliximab induction and maintenance in patients with moderate-to-severely active Crohn’s disease

Abstract Background Since 2021, subcutaneous (SC) infliximab (IFX) has been available for maintenance treatment of Crohn’s disease (CD) after an induction phase of 2 intravenous administrations of 5 mg/kg. The DIRECT-CD study is an ongoing randomised multicentre trial in which CD patients receive SC IFX also during induction. The applied SC IFX doses in the DIRECT-CD are based on population pharmacokinetics derived during maintenance treatment with SC IFX. We aimed to validate our induction regimen and correlate serum concentrations with clinical efficacy. Methods Patients with moderate-to-severe CD (Crohn’s disease activity index [CDAI]) &amp;gt;220 and endoscopic ulceration) received fixed SC IFX induction doses of 240 mg at week 0 and 2, followed by maintenance treatment (120 mg every other week). IFX serum concentrations and CDAI were evaluated at week 2, 4, 8, 14 and 26. Clinical remission was defined as a CDAI ≤150. For this analysis, body weight is defined as low if &amp;lt;80 kg and high if ≥80 kg. Results In total, 48 samples of 12 Crohn’s disease patients were analysed (Table 1). During the induction phase (week 2 and 4), observed IFX serum concentrations were lower than expected by the population pharmacokinetic model for all patients (median 15.0 µg/mL [IQR 9.4-20.0]). Moreover, concentrations were significantly lower in patients with a low versus high body weight (median 20.0 µg/mL [IQR 15.0-21.0] vs median 10.2 µg/mL [IQR 4.4-15.8], resp., P=0.004). During the maintenance phase (week 8, 14 and 26), median IFX serum concentrations were also higher in patients with a low body weight compared to patients with a high body weight (17.5 µg/mL [IQR 14.8-19.5] vs 8.9 µg/mL [IQR 5.8-13.8], P&amp;lt;0.001). No patients in the first quartile of IFX serum concentrations (≤7.0 µg/mL) at week 2 reached clinical remission at Week 8, whereas all patients who had an IFX serum concentration at week 2 of ≥15.0 µg/mL reached clinical remission at week 8. At the end of the study (week 26), clinical remission was reached in 67% of patients with a low body weight whereas only 33% of patients with a high body weight reached clinical remission. Conclusion These data implicate the importance of body weight in SC IFX dosing strategies. Based on these findings, SC IFX induction and maintenance treatment is changed to a weight-based dosing scheme in the ongoing DIRECT-CD trial.

P1049 Effectiveness and safety of subcutaneous infliximab in Crohn’s disease patients with immunogenic failure of intravenous infliximab

Abstract Background Immunogenicity is a major reason for secondary loss of response to infliximab (IFX). Recent work suggested potentially lower immunogenicity of subcutaneous compared to intravenous infliximab. However, it is unknown whether re-exposure of patients with immunogenic failure of IFX to its subcutaneous formulation is safe and effective. Here, we analysed the safety and effectiveness of subcutaneous IFX (CT-P13) in patients with Crohn’s disease (CD) and history of secondary loss of response of intravenous IFX due to anti-drug antibodies (ADA). Methods In a retrospective analysis conducted at medical centers in Germany (Dresden) and the Czech Republic (Prague), patients with clinical (Harvey-Bradshaw Index ≥ 5) and/or biochemical (faecal calprotectin &amp;gt;250 µg/g) active CD and previous treatment failure in the context of IFX immunogenicity underwent re-exposure to subcutaneous IFX. Treatment was initiated with either 4 subcutaneous injections 120 mg CT-P13 weekly followed by biweekly injections, or directly with 120 mg CT-P13 subcutaneous biweekly. Harvey-Bradshaw Index, faecal calprotectin, IFX serum concentration and ADA were assessed until month 12. Results Twenty CD patients were included (table 1). The majority of patients (90 %) had previous treatment with ≥ 3 biologics. 75% and 50 % of patients continued IFX treatment until month 6 and 12, respectively. No immediate hypersensitivity reactions were observed. Two patients (10%) discontinued IFX due to delayed hypersensitivity. Lack of treatment effectiveness led to infliximab withdrawal in 7 cases (35%) and one patient (5%) was lost to follow up after month 6. IFX serum concentrations increased from baseline (median 0 µl/ml ± 0 interquartile range/IQR) until month 12 (median 22.8 µl/ml, 10.0 IQR), while ADA levels decreased (50.6 AU/ml, 48.3 IQR and 0.0 AU/ml, 0 IQR at baseline and month 12, respectively). Clinical remission at month 12 was observed in 27% and biochemical remission in 38% of patients with active Crohn's disease at baseline. 67 % of patients with clinical inactive Crohn's disease at baseline remained in clinical remission until month 12. Conclusion Subcutaneous infliximab after previous failure and immunogenicity of intravenous infliximab was well tolerated and effective in a cohort of patients with refractory Crohn’s disease.

Development and validation of a novel therapeutic drug monitoring-based nomogram for prediction of primary endoscopic response to anti-TNF therapy in active Crohn's disease.

Anti-tumor necrosis factor (TNF) monoclonal antibodies, especially infliximab (IFX) and adalimumab (ADA), are considered the first-line treatment for active Crohn's disease (CD). However, the predictive role of therapeutic drug monitoring (TDM) of serum anti-TNF in monitoring the treatment of inflammatory bowel disease (IBD) remains controversial. To explore the correlation between serum anti-TNF levels and early endoscopic response in active CD using a TDM-based nomogram. Cross-sectional study. The simplified endoscopic activity score for CD (SES-CD), Crohn's disease activity index (CDAI), laboratory parameters, and the serum trough levels of IFX and ADA were assessed. The trough levels of IFX or ADA were significantly higher in patients with endoscopic response compared to non-responders in the development cohort (p < 0.001). The IFX and ADA levels showed a weak but significantly negative correlation with SES-CD (p < 0.001), CDAI (p < 0.001), and C-reactive protein (CRP) (p < 0.001) at week 14 post-IFX therapy in the development cohort. Furthermore, the receiver operating characteristic curve revealed that an optimal level of IFX (4.80 μg/mL) and ADA (8.80 μg/mL) exhibited the best performance in predicting endoscopic response. Concomitantly, we developed a novel nomogram prediction model based on the results of multivariate logistic regression analysis, which consisted of CRP, albumin (Alb), and anti-TNF trough levels at week 14. The nomogram showed significant discrimination and calibration for both IFX and ADA in the development cohort and performed well in the external validation cohort. This study demonstrates a robust association between serum concentrations of IFX, ADA, Alb, and CRP and primary endoscopic response in active CD patients. Importantly, the TDM- and laboratory marker-based nomogram may be used to evaluate the primary endoscopic response to anti-TNF therapy, especially for optimizing treatment strategies and switching therapy in CD patients.

Infliximab serum concentrations in luminal Crohn's disease and its relationship with disease activity: A multicentric cross-sectional study

ObjectivesIn Latin America, experience with monitoring serum Infliximab (IFX) concentrations is scarce. Our study aimed to compare IFX serum concentrations between patients with active disease or in remission. Patients and methodsA cross-sectional study was performed in patients with luminal Crohn's disease (CD) during maintenance treatment with IFX. Patients were classified as in remission or disease activity according to clinical scores and endoscopic, radiological, and laboratory markers. A comparison of IFX trough levels between the two groups was performed. Results80 CD patients were included [41 (51%) in remission and 39 (49%) with active disease]. In the analysis of general disease activity, the median serum levels of IFX in patients with remission and with active CD were 5.63 [0.03–14.40] vs. 3.84 [0.03–14.40] (p=0.287). Furthermore, there was no difference in serum IFX concentrations in endoscopic, radiological, and laboratory activities. Only in the clinical evaluation there was a significant difference in the median serum IFX levels between patients in remission and disease activity, 5.63 [0.03–14.40] vs. 2.14 [0.32–10.54] (p=0.042). ConclusionsIFX serum concentrations during maintenance treatment were similar in patients with luminal CD in remission and general, endoscopic, radiological, and laboratory disease activity. Patients with clinically active disease had lower IFX concentrations than patients in remission.

Therapeutic Drug Monitoring in Inflammatory Bowel Disease

AbstractInflammatory bowel disease (IBD) is a problem that directly affects the quality of life of patients suffering from this condition. Monitoring the serum level of infliximab (IFX) (TDM) is an important tool for guiding therapeutic decisions in IBD patients. The purpose of this study was to determine the significance of quantitatively measuring the serum level of IFX (TDM) and antibody to IFX (ATI). Methods and materials: Prospective observational study involving 40 IBD patients on IFX therapy, including 14 Proactive (week 06 of the induction phase) and 26 Reactive (maintenance phase). Immediately prior to the infusion, blood samples were drawn and measured using a Bulhlmann rapid test instrument. Serum concentrations of IFX were categorized as supratherapeutic (&gt;7.0 micrograms/ml), therapeutic (between 3.0 and 7.0 micrograms/ml), and subtherapeutic (3.0 micrograms/ml). When the serum concentration of IFX was 3 mcg/ml (subtherapeutic), the ATI was measured. 25 patients with CD and 15 patients with UC were evaluated. Only three of the twenty patients with subtherapeutic serum levels had a positive ATI, and both were reactive; two had CD and one had UC. There was a statistically significant difference between reactive and proactive patients with respect to levels of CRP (p = 0.042), with proactive DNS patients suffering greater alterations in CRP and albumin.

Comparison of monoclonal antibody disposition predictions using different physiologically based pharmacokinetic modelling platforms.

Physiologically based pharmacokinetic (PBPK) models can be used to leverage physiological and in vitro data to predict monoclonal antibody (mAb) concentrations in serum and tissues. However, it is currently not known how consistent predictions of mAb disposition are across PBPK modelling platforms. In this work PBPK simulations of IgG, adalimumab and infliximab were compared between three platforms (Simcyp, PK-Sim, and GastroPlus). Accuracy of predicted serum and tissue concentrations was assessed using observed data collected from the literature. Physiological and mAb related input parameters were also compared and sensitivity analyses were carried out to evaluate model behavior when input values were altered. Differences in serum kinetics of IgG between platforms were minimal for a dose of 1mg/kg, but became more noticeable at higher dosages (> 100mg/kg) and when reference (healthy) physiological input values were altered. Predicted serum concentrations of both adalimumab and infliximab were comparable across platforms, but were noticeably higher than observed values. Tissue concentrations differed remarkably between the platforms, both for total- and interstitial fluid (ISF) concentrations. The accuracy of total tissue concentrations was within a three-fold of observed values for all tissues, except for brain tissue concentrations, which were overpredicted. Predictions of tissue ISF concentrations were less accurate and were best captured by GastroPlus. Overall, these simulations show that the different PBPK platforms generally predict similar mAb serum concentrations, but variable tissue concentrations. Caution is therefore warranted when PBPK models are used to simulate effect site tissue concentrations of mAbs without data to verify the predictions.

Higher Serum Infliximab Concentrations Following Subcutaneous Dosing are Associated with Deep Remission in Patients with Inflammatory Bowel Disease

Abstract Background The relationship between subcutaneous infliximab [SC-IFX] concentrations and favourable therapeutic outcomes in patients with Crohn’s disease [CD] and ulcerative colitis [UC] remains elusive. Patients and Methods This cross-sectional study included consecutive adult patients with inflammatory bowel disease [IBD] treated with SC-IFX at a maintenance dose of 120 mg/2 weeks. Investigated therapeutic outcomes included sustained clinical remission; composite clinical and biomarker remission [clinical remission and C-reactive protein &amp;lt;5 mg/L]; biochemical remission [faecal calprotectin &amp;lt;250 µg/g]; and deep remission [clinical, biological, and biochemical remission]. Results Of 91 patients identified, 71 qualified for inclusion in the study [70% with CD; 27% with concomitant immunomodulators]. At the time of drug concentration measurement [median 13.5 months after switch], 55 [77%] patients had sustained clinical remission; n = 44 [62%] composite clinical and biomarker remission; n = 40 [56%] biochemical remission; and n = 31 [43%] deep remission. The mean SC-IFX concentrations were significantly higher in patients with sustained clinical remission [p = 0.014]; composite clinical and biomarker remission [p = 0.003]; biochemical remission [p &amp;lt; 0.001]; and deep remission [p &amp;lt; 0.001] compared to patients without having these outcomes. In multivariate analysis, SC-IFX concentration was the only factor independently associated with sustained clinical remission (odds ratio [OR]: 4.7, 95% confidence interval [CI]: 3.1–12.2, p = 0.005); clinical and biomarker remission [OR: 9.21, 95% CI: 6.09–18.7, p = 0.006]; biochemical remission [OR: 37, 95% CI: 14–39.3, p &amp;lt; 0.001]; and deep remission [OR: 29, 95% CI: 15.7–37.4, p &amp;lt; 0.001]. The optimal SC-IFX concentration cut-off associated with deep remission based on ROC analysis was 20 µg/mL [sensitivity: 0.91, specificity: 0.80, accuracy: 0.85]. Combination with an immunomodulator failed to improve SC-IFX pharmacokinetics. Conclusion Higher SC-IFX concentrations are associated with higher rates of favourable therapeutic outcomes in IBD patients. Serum SC-IFX concentrations &amp;gt;20 µg/mL were significantly associated with deep remission.

Serum levels of infliximab and adalimumab are associated with deep remission in inflammatory bowel disease

ObjectiveDeep remission defined by clinical-biomarker remission and mucosal healing has emerged as a new therapeutic target in inflammatory bowel disease. The aim of this study was to define an optimal cut-off concentration for infliximab and adalimumab during maintenance therapy associated with deep remission. The secondary objective, was to evaluate the influence of variables on anti tumor necrosis factor-alpha concentrations and deep remission. MethodRetrospective study including 120 and 122 patients inflammatory bowel disease diagnosed who received maintenance therapy with infliximab and adalimumab. Biomarker remission was considered by C-reactive protein < 5 mg/L and fecal calprotectin < 100 µg/g. Crohn's disease clinical remission was defined by a Harvey Bradshaw score < 5 and mucosal healing by a simple endoscopic score for Crohn's disease< 3. In ulcerative colitis, it was defined as a Mayo total score < 3 and Mayo endoscopic subscore < 2. Receiver operating characteristic test was performed to determine drug concentration thresholds associated with deep remission. Anti tumor necrosis factor-alpha concentrations were classified into quartiles. X2 and Kruskal-Wallis test were used to compare discrete and continuous variables between quartile groups. Multivariate logistic regression was performed to identify patient characteristics and serological facto C-reactive protein rs associated with deep remission. ResultsAnti tumor necrosis factor-alpha concentrations were higher in patients with deep remission, in infliximab (4.4, interquartile range: 3.3-6.5 vs 2.3, interquartile range: 1.1-4.2 µg/mL, P < 0.005) and adalimumab (6.3, interquartile range: 4.2-8.2 vs 3.9, interquartile range: 2.4-5.5 µg/mL, P < 0.005). A Receiver operating characteristic test identified a concentration threshold of 3.1 µg/mL in infliximab (area under the Receiver operating characteristic test curve, 0.72) and 6.3 µg/mL in adalimumab (area under receiver operating characteristic test curve, 0.75) associated with deep remission. Factors associated with the highest quartiles of serum infliximab concentration were: elevated body mass index, absence of previous inflammatory bowel disease-surgery, C-reactive protein < 5 mg/L, and fecal calprotectin < 100 µg/g. In adalimumab, higher quartiles were related to concomitant immunosuppressants, low body mass index, absence of previous inflammatory bowel disease-surgery, and C-reactive protein < 5 mg/L and fecal calprotectin < 100 µg/g. Multivariate regression identified fecal calprotectin < 100 µg/g, C-reactive protein < 5 mg/L, infliximab > 3.1 µg/mL and adalimumab concentrations > 6.3 µg/mL as factors significantly associated with deep remission. ConclusionsTrough infliximab and adalimumab concentrations, C-reactive protein < 5 mg/L and fecal calprotectin < 100 µg/g are associated with deep remission during maintenance therapy. Cutoff point of 3.1 and 6.3 g/mL for infliximab and adalimumab respectively, were identified as deep remission predictors.

Serum Concentrations of Infliximab and IL-6 for Predicting One-Year Discontinuation of Infliximab Treatment Owing to Secondary Non-response in Patients with Rheumatoid Arthritis.

Secondary non-response to infliximab (IFX) occurs in some patients with rheumatoid arthritis (RA). Although therapeutic drug monitoring (TDM) is a useful tool to optimize IFX therapy, it is unclear whether it can help to identify the risk of secondary non-response. This study aimed to explore the utility of serum levels of IFX or other biomarkers to predict IFX discontinuation owing to secondary non-response. A single-center, retrospective study was conducted using the Kyoto University Rheumatoid Arthritis Management Alliance cohort database between 2011 and 2020. Serum IFX levels were measured using liquid chromatography-tandem mass spectrometry. An electrochemiluminescence assay was used to quantify serum levels of tumor necrosis factor-α and interleukin-6 and detect anti-drug antibodies. Eighty-four out of 310 patients were eligible for this study. The cutoff levels of biomarkers were determined by receiver operating characteristic analysis. IFX persistence was similar between groups stratified using IFX levels, tumor necrosis factor-α levels, interleukin-6 levels, and anti-drug antibodies positivity. The group with lower IFX and higher interleukin-6 levels had the worst therapy persistence (p = 0.017) and the most frequent disease worsening (90.0%, p < 0.001). Evaluating both interleukin-6 and IFX levels, not just IFX alone, enabled us to identify patients at risk of discontinuing IFX treatment. These findings support the utility of measuring IFX and interleukin-6 levels for successful maintenance therapy for RA.

Validation Study of Novel Point-of-Care Tests for Infliximab, Adalimumab and C-Reactive Protein in Capillary Blood and Calprotectin in Faeces in an Ambulatory Inflammatory Bowel Disease Care Setting.

Background and aims: Point-of-care tests (POCT) allow instant measurement of inflammatory markers and drug concentrations. Here, we studied agreement between a novel POCT device and reference methods of measuring infliximab (IFX) and adalimumab (ADL) serum concentrations and C-reactive protein (CRP) and faecal calprotectin (FCP) concentrations of patients with inflammatory bowel disease (IBD). Methods: In this single-centre validation study, IBD patients were recruited in which IFX, ADL, CRP and/or FCP tests were required. IFX, ADL and CRP POCT were performed on capillary whole blood (CWB), obtained via finger prick. Additionally, IFX POCT was performed on serum samples. FCP POCT was performed on stool samples. Agreement between POCT and reference methods was tested using Passing-Bablok regression, intra-class correlation coefficients (ICC) and Bland-Altman plots. Results: In total, 285 patients participated. Passing-Bablok regression identified differences between the reference method and IFX CWB POCT (intercept = 1.56), IFX serum POCT (intercept = 0.71, slope = 1.10) and ADL CWB POCT (intercept = 1.44). There were also differences in the Passing-Bablok regressions of CRP (intercept = 0.81, slope = 0.78) and FCP (intercept = 51 and slope = 0.46). Bland-Altman plots demonstrated that IFX and ADL concentrations were slightly higher with the POCT and CRP and FCP were slightly lower with POCT. The ICC demonstrated almost perfect agreement with IFX CWB POCT (ICC = 0.85), IFX serum POCT (ICC = 0.96), ADL CWB POCT (ICC = 0.82) and CRP CWB POCT (ICC = 0.91) and moderate agreement with FCP POCT (ICC = 0.55). Conclusions: IFX and ADL results were slightly higher with this novel rapid and user-friendly POCT, whereas CRP and FCP results were slightly lower compared to the reference methods.

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.