Presence Of Anti-drug Antibodies Research Articles

Anti-Drug Antibodies in Patients with Inflammatory Bowel Diseases Treated with Biosimilar Infliximab: A Prospective Cohort Study.

Reports of the prevalence of antibodies to infliximab (anti-drug antibodies, ADA) are inconsistent due in part to the various assay formats used to monitor immunogenicity in the clinic and under clinical trial settings. This study aimed to determine the frequency of ADA in patients with inflammatory bowel disease (IBD) during induction and maintenance therapy with biosimilar infliximab (CT-P13) using the ELISA (enzyme-linked immunosorbent assay) method. In this prospective single-center study, we analyzed the incidence of ADA and the relationship between the presence of ADA and the following variables: gender, type of disease, immunosuppressive therapy used, and duration of treatment. A total of 84 patients with IBD received CT-P13 and were followed up for an average of 7 months. We found ADA in 50% of the patients with undetectable levels of the drug. The percentage of persons with antibodies detected during induction treatment was 11.3% compared to 9.6% during maintenance therapy. The analysis showed no relationship between response to treatment and antibody titers (p = 0.381). The study showed a statistically significant relationship between undetectable levels of CT-P13 and the presence of ADA at week 6 of therapy (i.e., ADA were detected in all the patients with undetectable levels of CT-P13). Patients with IBD and undetectable levels of CT-P13 before administration of the third induction dose were at high risk of the presence of anti-drug antibodies as well as primary non-response.

BAFF predicts immunogenicity in older patients with rheumatoid arthritis treated with TNF inhibitors

Immunogenicity related to treatment with TNF inhibitors (TNFi) is one of the causes for the decreased attainment of clinical response in patients with rheumatoid arthritis (RA). The B-cell activating factor (BAFF) may be playing a role in the development of immunogenicity. The objective of this study was to analyse the association of baseline concentration of serum B-cell activating factor (BAFF) with immunogenicity after 6 months of TNFi treatment. A total of 127 patients with RA starting a TNFi (infliximab, adalimumab, certolizumab pegol or golimumab) were followed-up for 6 months. Serum samples were obtained at baseline and at 6 months and anti-drug antibody (ADA) and BAFF concentrations were measured. Logistic regression models were employed in order to analyse the association between BAFF concentrations and immunogenicity. Receiver operating characteristic analysis was performed to determine the BAFF concentrations with a greater likelihood of showing immunogenicity association. At 6 months, 31 patients (24%) developed ADA. A significant interaction between the age and baseline BAFF concentration was found for the development of ADA (Wald chi-square value = 5.30; p = 0.02); therefore, subsequent results were stratified according to mean age (≤ / > 55 years). Baseline serum BAFF concentration was independently associated with ADA development only in patients over 55 years (OR = 1.51; 95% CI 1.03–2.21). Baseline serum BAFF ≥ 1034 pg/mL predicted the presence of ADA at 6 months (AUC = 0.81; 95% confidence interval (CI) 0.69–0.93; p = 0.001; positive likelihood ratio = 3.7). In conclusion, our results suggest that the association of BAFF concentration and immunogenicity depends on the patient’s age. Baseline serum BAFF concentration predicts the presence of ADA within 6 months of TNFi therapy in older patients with RA.

P299 Loss-of-response to anti-tumour necrosis factor-α critically depends on treatment duration in patients with Inflammatory Bowel Disease

Abstract Background Inflammatory bowel disease (IBD) is often managed with anti-tumour necrosis factor-α (anti-TNFα) compounds, but only few studies have reported on long-term outcomes. We aimed to determine whether the incidence of loss-of-response decreases with longer treatment duration. Methods In a multicentre, retrospective cohort study of patients with IBD who received anti-TNFα for at least 4 months between 2011-2019, we compared incidence rates of loss-of-response between different intervals of treatment duration and performed parametric survival modelling to assess changes with longer treatment duration. Cox regression analysis was performed to identify predictors of loss-of-response. Secondary outcomes included overall anti-TNFα discontinuation and dose escalation. Results We included 900 anti-TNFα treatment episodes in 746 individual patients, with up to 9 years of follow-up. During follow-up, the most frequently observed reason for anti-TNFα discontinuation was loss-of-response (Figure 1), which occurred in 231 (25.7%) episodes, with presence of anti-drug antibodies in 67/231 (29%). Within the first year, the incidence of loss-of-response was threefold higher than after four years of treatment (17.3% versus 4.7% per patient-year, p<0.001). The incidence of overall drug discontinuation (28.6% versus 14.0% per patient-year, p<0.001) and dose escalations (36.5% versus 6.4% per patient-year, p<0.001) also decreased significantly from the first year to after four years, respectively. Risk factors for loss-of-response included stricturing or penetrating Crohn’s disease (adjusted hazard ratio [aHR] 1.67, 95% CI 1.14 – 2.44), while male sex (aHR 0.74, 95% CI 0.56 – 0.98) and concomitant immunomodulators (aHR 0.73, 95% CI 0.54 – 0.98) were protective. Conclusion Long-term use of anti-TNFα maintenance treatment is associated with a reduced risk of loss-of-response in patients with IBD.

Results From an Open-Label Extension of the Phase 2 Dose Finding Study of Once Weekly Somatrogon vs Daily Genotropin in Pediatric Patients With Growth Hormone Deficiency (GHD)

Abstract Background: Somatrogon, a long-acting recombinant human growth hormone, is being developed as a once weekly treatment for pediatric patients (pts) with GHD. A phase 2, 12 month study (NCT01592500) in pts with GHD showed that weekly somatrogon at 0.66 mg/kg/week had similar efficacy and safety to daily Genotropin. Pts who completed 12 months of treatment could be enrolled into an open-label extension (OLE). Aims: Evaluate the safety and efficacy of long-term exposure to somatrogon in pediatric pts with GHD who continued in the OLE for up to an additional 5 years. Methods: Methods for the main phase 2 study were published previously (Zelinska et al, 2017), in which 53 pts were randomized to 1 of 3 weekly somatrogon dose cohorts (0.25, 0.48, and 0.66 mg/kg/week) or the daily Genotropin cohort (0.24 mg/kg/week) for 12 months. After the main study (Periods I/II), 48 pts who consented to participate continued in the OLE, consisting of 3 periods: Period III=12 additional months at original somatrogon dose (Genotropin recipients randomized to 1 of the 3 somatrogon dose regimens); Period IV=subsequent years 2-4 with all pts receiving somatrogon at 0.66 mg/kg/week; Period V=ongoing, with pts transitioned from the vial to a pre-filled pen device at the same somatrogon dose (0.66 mg/kg/week). Data up to 1 year of Period V are reported. Results: Overall subject retention in different periods of this long-term study ranged from 87.5% to 97.7%. 39 pts (81.3%) reported at least one treatment-emergent adverse event (TEAE). Most TEAEs were mild or moderate in intensity and most were classified as unrelated to study treatment. 3 pts (6.3%) reported at least 1 serious adverse event (SAE); most SAEs were considered unrelated to study treatment, except for 1 instance of scoliosis. At the end of Period III, the mean annual height velocity (HV) was similar for the 0.25 and 0.48 mg/kg/week dose cohorts (7.73±1.89 and 7.54±1.28 cm/year, respectively) but was higher in the 0.66 mg/kg/week dose cohort (8.81±1.12 cm/year), consistent with the results of the main study. The HV at Periods IV and V showed sustained growth response. Height SDS showed consistent improvement and near normalization of height for age and gender after up to 6 years on somatrogon, irrespective of initial cohort assignment; height SDS at baseline of the main study was -3.98±1.22 and was well within the normal range at -0.69±0.87 at the end of Year 1 in Period V. IGF-1 SDS values remained above baseline and were maintained within the therapeutic target range with weekly somatrogon treatment at all time points in all OLE periods. Anti-drug antibodies (ADAs) were reported in 18 pts, of which 10 pts had ADAs in the main study. The presence of ADAs did not impact efficacy or safety. Conclusions: Somatrogon administered once weekly for up to 5 years after the main study was generally well tolerated and participants showed sustained improvement in annual HV, height SDS, and delta height SDS.

Therapeutic drug monitoring of anti-TNF drugs: an overview of applicability in daily clinical practice in the era of treatment with biologics in juvenile idiopathic arthritis (JIA)

BackgroundAnti-tumor necrosis factor (TNF) drugs have improved the prognosis for juvenile idiopathic arthritis (JIA) significantly. However, evidence for individual treatment decisions based on serum anti-TNF drug levels and the presence of anti-drug antibodies (ADAbs) in children is scarce. We aimed to assess if anti-TNF drug levels and/or ADAbs influenced physician’s treatment decisions in children with JIA.MethodsPatients’ records in our center were retrospectively screened for measurements of anti-TNF drug levels and ADAbs in children with JIA using etanercept, adalimumab or infliximab. Clinical characteristics and disease activity were retrieved from patient charts.ResultsWe analyzed 142 measurements of anti-TNF drug levels in 65 children with JIA. Of these, ninety-seven (68.3%) were trough concentrations. N = 14/97 (14.4%) of these showed trough concentrations within the therapeutic drug range known for adults with RA and IBD. ADAbs against adalimumab were detected in seven patients and against infliximab in one patient. Seven (87,5%) of these ADAb-positive patients had non-detectable drug levels. A flowchart was made on decisions including rational dose escalation, stopping treatment in the presence of ADAbs and undetectable drug levels, showing that 45% of measurements influenced treatment decisions, which concerned 65% of patients (n = 42/65).ConclusionsIn the majority of patients, measurement of anti-TNF drug levels led to changes in treatment. A wide variation of anti-TNF drug levels was found possibly due to differences in drug clearance in different age groups. There is need for determination of therapeutic drug ranges and pharmacokinetic curves for anti-TNF and other biologics in children with JIA.

A nationwide survey on therapeutic drug monitoring of anti-tumour necrosis factor agents for inflammatory bowel disease.

Routine therapeutic drug monitoring (TDM) during treatment with anti-tumour necrosis factor (anti-TNF) agents in inflammatory bowel disease may increase treatment efficacy and cost-effectiveness, and reduce the risk of loss of response. To assess the current use of anti-TNF agent TDM, including trough concentration and anti-drug antibodies, among gastroenterology practitioners in New Zealand. A web-based survey was delivered to gastroenterologists and advanced trainees in New Zealand, identified by the New Zealand Society of Gastroenterology. The response rate was 36% (48/134). Adalimumab was the most common initial anti-TNF agent used (78%, infliximab 22%). Ninety-three percent of those who completed the survey used TDM, mainly in cases of non-response or loss or response. Most respondents (93% and 83% for adalimumab and infliximab, respectively) measured trough concentrations within 24 h prior to the next administration. In patients in clinical remission but with endoscopic inflammation on anti-TNF agents, 72% would measure drug concentrations. In the presence of anti-drug antibodies, 45% would add an immunomodulator in patients with active disease and 47% would add an immunomodulator in patients in remission. With low trough concentrations, 77% would make no changes if the patient was in remission, and 75% would increase the dose in case of active disease. TDM was routinely used among inflammatory bowel disease gastroenterology clinicians who responded to this survey. However, interpretation of results and decision-making is variable, suggesting more guidance is required.

Pharmacokinetic Modelling of Human Recombinant Protein, p75ECD-Fc: A Novel Therapeutic Approach for Treatment of Alzheimer's Disease, in Serum and Tissue of Sprague Dawley Rats.

p75ECD-Fc is a novel antagonist of toxic amyloid beta protein and other neurodegenerative factors with potential for the treatment of Alzheimer's disease (AD). Preclinical studies showed that it can alleviate the AD pathologies in animal models of dementia. In a previous paper, we used non-compartmental pharmacokinetic analysis to obtain preliminary pharmacokinetic data for p75ECD-Fc in Sprague Dawley (SD) rats. We also studied the tissue distribution in terms of drug metabolism that helped us to understand possible mechanisms of action. Here, we aim to develop population pharmacokinetic models that can describe the pharmacokinetics of p75ECD-Fc in serum and tissues. p75ECD-Fc was delivered to SD rats via two routes (intravenous and subcutaneous) at a single dose of 3 mg/kg (n = 15). Blood (n = 12) and tissue samples (n = 10-15) were then separated at different time points for a total duration of 42 days post dosage. The concentration of p75ECD-Fc in serum and tissues was measured using an enzyme-linked immunosorbent assay. Data were best fitted to a 2-compartment model with linear elimination kinetics. The population parameter estimates for clearance, and volume of central and peripheral compartments were 0.000176 L/h, 0.0145 L and 0.0263 L, respectively. The presence of anti-drug antibodies was added to the final model as a covariate on clearance. The subcutaneous bioavailability was estimated to be 53.5% with a first-order absorption rate constant of 0.00745 1/h. By modeling of individual tissue concentrations, p75ECD-Fc was found to exhibit modest tissue distribution with estimated tissue/plasma partition coefficients (R) ranging from 0.004 to 0.2. This is the first report of a pharmacokinetic model for p75ECD-Fc and these results may facilitate the ongoing development of p75ECD-Fc and translation to clinical studies.

Rapid point-of-care anti-infliximab antibodies detection in clinical practice: comparison with ELISA and potential for improving therapeutic drug monitoring in IBD patients.

Anti-drug antibodies can interfere with the activity of anti-tumor necrosis factor (TNF) agents by increasing drug clearance via direct neutralization. The presence of anti-drug antibodies is clinically relevant when trough drug concentrations are undetectable or sub-therapeutic. However, traditional immunoassay is not easily and rapidly accessible, making the translation of the results into treatment adjustment difficult. The availability of a point-of-care (POC) test for therapeutic drug monitoring (TDM) might represent an important step forward for improving the management of inflammatory bowel disease (IBD) patients in clinical practice. In this pilot study, we compared the results obtained with POC tests with those obtained by enzyme-linked immunosorbent assay (ELISA) in a group of IBD patients treated with Infliximab (IFX). We showed that POC test can reliably detect presence of antibody-to-IFX with 100% of specificity and 76% sensitivity, in strong agreement with the ELISA test (k-coefficient = 0.84).

Clinical Relevance of Anti-TNF Antibody Trough Levels and Anti-Drug Antibodies in Treating Inflammatory Bowel Disease Patients

Background and Aims: The majority of patients treated with anti-tumor necrosis factor (TNF) therapy develop anti-drug antibodies (ADAs), which might result in loss of treatment efficacy. Strict guidelines on measuring trough levels (TLs) and ADA in clinical routine do not exist. To provide real-world data, we took advantage of our tertiary inflammatory bowel disease (IBD) center patient cohort and determined indicators for therapeutic drug monitoring (TDM) and actual consequences in patient care. Methods: We retrospectively collected clinical data of 104 IBD patients treated with infliximab or adalimumab in our IBD clinic. Patients with TL and ADA measurements between June 2015 and February 2018 were included. Results: The main reason for determining TL was increased clinical disease. Subtherapeutic TLs were found in 33 patients, therapeutic TLs in 33 patients, and supratherapeutic TLs in 38 patients. Adjustments in anti-TNF therapy occurred more frequently (p = 0.01) in patients with subtherapeutic TL (24 of 33 patients; 73%) as compared to patients with therapeutic and supratherapeutic TLs (26 of 71 patients; 37%). No correlation could be found between TL and disease activity (p = 0.16). Presence of ADA was found in 16 patients, correlated with the development of infusion reactions (OR: 10.6, RR: 5.4, CI: 2.9–38.6), and was associated with subtherapeutic TL in 15 patients (93.8%). Treatment adaptations were based on TL and/or ADA presence in 36 of 63 patients. Conclusions: TDM showed significant treatment adaptations in patients with subtherapeutic TL. Conversely, in patients with therapeutic and supratherapeutic TLs, reasons for adaptations were based on considerations other than TL, such as clinical disease activity. Further studies should focus on decision-making in patients presenting with supratherapeutic TL in remission.

Immunogenicity of Biologic and Biosimilar Therapies for Psoriasis and Impact of Novel Immunoassays for Immunogenicity Detection.

Anti-drug antibodies (ADAs) may develop against originator biologic and biosimilar therapies used for the treatment of psoriasis and may be the cause of initial therapeutic non-response or diminished therapeutic response over time. Comparing immunogenicity between therapeutic agents is challenging owing to the variation in assays used for detection, among other reasons. Using the results of a PubMed search for psoriasis clinical trials disclosing the rates of ADAs for originator biologic and biosimilar therapies approved for the treatment of psoriasis within the last 5 years, this review discusses the rates and potential clinical impact of ADA formation in patients with psoriasis managed with originator biologic and biosimilar therapies, along with novel methods of ADA testing. Anti-drug antibodies are detectable in all biologic and biosimilar therapies approved for the treatment of psoriasis in the last 5 years, and the effect of ADAs on clinical response varies by agent. Novel immunoassays used for the detection of ADAs may have increased sensitivity compared with traditional assays, although the increased rate of detection may not correlate with decreased clinical response and the decision to test for the presence of ADAs may vary from patient to patient. Though ADA formation seems ubiquitous with the use of biologic agents for the treatment of psoriasis, the increased rates of ADAs detected by novel immunoassays may not necessarily correlate with decreased treatment efficacy.

Factors Associated with the Immunogenicity of Anti-Tumor Necrosis Factor Agents in Pediatric Patients with Inflammatory Bowel Disease.

Background/AimsAnti-drug antibodies (ADAs) can develop during treatment with anti-tumor necrosis factor (TNF) agents. We aimed to investigate the factors associated with immunogenicity of anti-TNF agents in pediatric patients with inflammatory bowel disease (IBD) and observe the clinical course of ADA-positive patients.MethodsPediatric IBD patients receiving maintenance treatment with anti-TNF agents who had been tested for ADAs against infliximab (IFX) or adalimumab (ADL) were included in this cross-sectional study. Factors associated with ADA positivity were investigated by analyzing clinicodemographic, laboratory, and treatment-related factors.ResultsA total of 76 patients (Crohn’s disease, 65; ulcerative colitis, 11) were included. Among these, 59 and 17 patients were receiving IFX and ADL, respectively. ADAs were found in 10 patients (13.2%), all of whom were receiving IFX. According to multivariable logistic regression analysis, the IFX trough level (TL) was associated with ADA positivity (odds ratio, 0.25; 95% confidence interval [CI], 0.08 to 0.51; p=0.002). According to the receiver operating characteristic analysis, the optimal cutoff of the IFX TLs for stratifying patients based on the presence of ADAs against IFX was 1.88 μg/mL (area under curve, 0.941; 95% CI, 0.873 to 1.000; sensitivity, 80.0%; specificity, 95.9%; p<0.001). Among the 10 patients with ADAs against IFX, five patients (50%) switched to ADL within 1 year, while five patients (50%) kept receiving IFX. Transient ADAs were observed in three patients (30%).ConclusionsIFX TL was the only factor associated with ADA formation in pediatric IBD patients receiving IFX. Future studies based on serial and proactive therapeutic drug monitoring are required in the future.

Efficacy and Safety of CT-P13 in Inflammatory Bowel Disease after Switching from Originator Infliximab: Exploratory Analyses from the NOR-SWITCH Main and Extension Trials.

BackgroundThe NOR-SWITCH main and extension trials demonstrated that switching from originator to biosimilar infliximab (CT-P13) is efficacious and safe across six diseases. However, a subgroup analysis of Crohn’s disease (CD) in the main trial displayed a close to significant difference favouring originator infliximab, and more scientific data have therefore been requested. ObjectiveThe aim was to assess treatment efficacy, safety, and immunogenicity in an explorative subgroup analysis in CD and ulcerative colitis (UC) in the NOR-SWITCH trials.Patients and MethodsThe 52-week, randomised, non-inferiority, double-blind, multicentre, phase 4 NOR-SWITCH study was followed by a 26-week open extension trial where all patients received treatment with CT-P13. Treatment efficacy, safety, and immunogenicity in CD and UC were assessed throughout the 78-week study period.ResultsThe main and extension trials included 155 and 93 patients with CD and 93 and 80 patients with UC, respectively. Demographic and baseline characteristics were comparable in both treatment arms within patient groups. There were no differences in the main and extension trials regarding changes in activity indices, C-reactive protein, faecal calprotectin, patient’s and physician’s global assessment of disease activity and patient-reported outcome measures in CD and UC. Moreover, comparable results were also demonstrated for trough serum levels, presence of anti-drug antibodies, and reported adverse events.ConclusionEfficacy, safety, and immunogenicity of both the originator and biosimilar infliximab were comparable in CD and UC in the NOR-SWITCH main and extension trials. These explorative subgroup analyses confirm that there are no significant concerns related to switching from originator infliximab to CT-P13 in CD and UC.Trial RegistrationClinicalTrials.gov, number NCT02148640.Electronic supplementary materialThe online version of this article (10.1007/s40259-020-00438-7) contains supplementary material, which is available to authorized users.

Modelling of the relationship between infliximab exposure, faecal calprotectin and endoscopic remission in patients with Crohn's disease.

Evidence for the benefits of pharmacokinetic (PK) and pharmacodynamic (PD) monitoring of infliximab in patients with Crohn's disease (CD) remains scarce. We aimed to develop a population (pop)PK/PD model to characterise the infliximab dose-exposure-biomarker-response (faecal calprotectin [fCal] and endoscopic remission [ER]) relationship. Data were obtained from 116 patients with CD in a phase 4 dose-escalation study. Three sequential models were developed: a 2-compartment popPK model linking infliximab dose to exposure; an indirect response popPK/PD model describing the inhibitory effect of infliximab exposure on fCal; and a first-order Markov popPD model linking fCal to transitions between states of ER, no ER and dropout. Infliximab clearance increased with increasing fCal, decreasing albumin, increasing CD activity index and presence of anti-drug antibodies. Baseline fCal increased with increasing C-reactive protein and decreasing platelet count. Lower fCal increased the probability of attaining ER and decreased the probability of losing ER. Probability of dropping out given an earlier state of absence of ER increased with time. Large interpatient PK and PD variability resulted in a flat dose-response curve. Predicted fraction of patients achieving ER was 45% [30-61] (median [interquartile range], n = 50 000) when on 5 mg/kg infliximab (~46% observed in data). Simulations with 10 mg/kg induction doses predicted an increase to 48% [32-63]. This minor benefit at the population level argues against systematic 10 mg/kg induction dosing in all patients. Model-informed infliximab dose optimisation towards a predefined fCal concentration (while accounting for PK and PD variability) may improve effectiveness of infliximab therapy.

Optimizing Antitumor Necrosis Factor Treatment in Pediatric Inflammatory Bowel Disease With Therapeutic Drug Monitoring.

Biological agents have revolutionized inflammatory bowel disease treatment but primary nonresponse and secondary loss of response are common with resulting adverse outcomes. Clinical trials demonstrated an association between serum drug concentrations, as well as the presence of antidrug antibodies, and loss-of-response. Therapeutic drug monitoring (TDM), defined as the evaluation of drug concentrations and antidrug antibodies, is appearing as a strategy to optimize treatment and take full advantage from these drugs. TDM appears to be a promising tool in clinical practice, especially in pediatric patients, who have pronounced fluctuations in the pharmacokinetics of the drugs.The authors present a literature review about antitumor necrosis factor therapy optimization based on personalized treatment strategies according to TDM and possible strategies to recapture loss of response, including an algorithm for practical management.

Host cell proteins induce inflammation and immunogenicity as adjuvants in an integrated analysis of in vivo and in vitro assay systems

IntroductionHost cell proteins (HCPs) are contaminated proteins remaining after purification of biopharmaceuticals. Recent reports revealed clinical implications of HCPs in anti-drug antibody (ADA) development in patients without any inflammatory effects. Therefore, we evaluated the inflammatory effects and immunogenicity of HCPs in an in vivo study by intravitreal administration to rabbits and an in vitro THP-1 cells assay. MethodsEscherichia coli-derived HCPs at 200 ng/eye with or without ranibizumab at 0.25 mg/eye were administrated intravitreally to rabbits. For in vitro examination, differentiated THP-1 cells were stimulated with HCPs at 0.17 to 10.88 μg/mL with or without ranibizumab at 0.2 mg/mL. ResultsCo-administration of HCPs with ranibizumab, but not HCPs alone, induced ocular inflammation. Presence of ADA (anti-ranibizumab) was detected in the vitreous fluid of rabbits in which HCPs and ranibizumab were co-administered. HCPs increased cytokine release and upregulated cell surface markers involved in the antigen presentation in the THP-1 cell assay, which was enhanced by co-stimulation with ranibizumab. DiscussionThese finding suggests that HCPs may induce inflammation and immunogenicity as an adjuvant. Furthermore, integrated analyses by an in vivo rabbit model and in vitro assay system using THP-1 cells would be useful to evaluate the immunological risk of HCPs.

Pharmacokinetic Variability of Therapeutic Antibodies in Humans: A Comprehensive Review of Population Pharmacokinetic Modeling Publications.

The pharmacokinetics of monoclonal antibodies is highly variable among patients. Several factors of variability, referred to as covariates in pharmacokinetic modeling, are known to influence this variability, such as body size, sex, antigen mass, serum albumin levels, or the presence of anti-drug antibodies. We propose a quantitative overview of the occurrence of assessment and detection of the main covariates associated with monoclonal antibody pharmacokinetics by comprehensively examining all population pharmacokinetic studies of monoclonal antibodies in humans. If some covariates are often assessed and detected (such as body size, antigen mass, or serum albumin levels), others are less frequently assessed but still may be relevant (e.g., anti-drug antibodies or endogenous immunoglobulin G levels). There is still a large heterogeneity in the relevance, availability, measurement, coding, detection, and interpretation of covariates. These issues deserve thorough investigation, which will help to design the optimal dosing strategy for every monoclonal antibody during its entire lifespan.

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.

GloBody Technology: Detecting Anti-Drug Antibody against VH/VL domains

The occurrence of anti-drug antibodies following administration of therapeutic monoclonal antibody to patients is a growing problem that is attracting attention from frontline clinicians. Ideally, an initial indicative point of care test would provide guidance to seek testing approved by the regulatory authorities. Here we describe a platform for the detection of IgG anti-drug antibodies that may provide an initial screen for all therapeutic monoclonal antibodies. Synthetic genes encoding Nanoluciferase polypeptides were inserted between the variable heavy and light domain encoding region of known antibody drugs (alemtuzumab and adalimumab) to generate recombinant single chain GloBodies, which retain the drug antibody paratopes and Nanoluciferase activity. In the presence of anti-drug antibodies, the GloBody is bound by specific IgG in the sample. These complexes are captured on immobilised Protein G and the luciferase activity determined. The amount of light generated being indicative of the anti-drug IgG antibody levels in serum. It should be possible to assemble GloBody reagents for all therapeutic monoclonal antibodies and adapt the capture phase to include additional specific isotypes. The assay has the potential to be developed for use with a drop of blood allowing initial pre-screening in a point of care setting.

In Vitro ELISA and Cell-Based Assays Confirm the Low Immunogenicity of VNAR Therapeutic Constructs in a Mouse Model of Human RA: An Encouraging Milestone to Further Clinical Drug Development.

Anti-drug antibodies (ADAs), specific for biotherapeutic drugs, are associated with reduced serum drug levels and compromised therapeutic response. The impact of ADA on the bioavailability and clinical efficacy of blockbuster anti-hTNF-α monoclonal antibodies is well recognised, especially for adalimumab and infliximab treatments, with the large and complex molecular architecture of classical immunoglobulin antibody drugs, in part, responsible for the immunogenicity seen in patients. The initial aim of this study was to develop solid-phase enzyme-linked immunosorbent assays (ELISA) and an in vitro cell-based method to accurately detect ADA and estimate its impact on the preclinical in vivo efficacy outcomes of two novel, nonimmunoglobulin VNAR fusion anti-hTNF-α biologics (Quad-X™ and D1-NDure™-C4) and Humira®, a brand of adalimumab. Serum drug levels and the presence of ADA were determined in a transgenic mouse model of polyarthritis (Tg197) when Quad-X™ and Humira® were dosed at 1 mg/kg and D1-NDure™-C4 was dosed at 30 mg/kg. The serum levels of the Quad-X™ and D1-NDure™-C4 modalities were consistently high and comparable across all mice within the same treatment groups. In 1 mg/kg and 3 mg/kg Quad-X™- and 30 mg/kg D1-NDure™-C4-treated mice, an average trough drug serum concentration of 8 μg/mL, 50 μg/mL, and 350 μg/mL, respectively, were estimated. In stark contrast, Humira® trough serum concentrations in the 1 mg/kg treatment group ranged from <0.008 μg/mL to 4 μg/mL with trace levels detected in 7 of the 8 animals treated. Trough serum Humira® and Quad-X™ concentrations in 3 mg/kg treatment samples were comparable; however, the functionality of the detected Humira® serum was significantly compromised due to neutralising ADA. The impact of ADA went beyond the simple and rapid clearance of Humira®, as 7/8 serum samples also showed no detectable capacity to neutralise hTNF-α-mediated cytotoxicity in a murine fibrosarcoma (L929) cell assay. The neutralisation capacity of all the VNAR constructs remained unchanged at the end of the experimental period (10 weeks). The data presented in this manuscript goes some way to explain the exciting outcomes of the previously published preclinical in vivo efficacy data, which showed complete control of disease at Quad-X™ concentrations of 0.5 mg/kg, equivalent to 10x the in vivo potency of Humira®. This independent corroboration also validates the robustness and reliability of the assay techniques reported in this current manuscript, and while it comes with the caveat of a mouse study, it does appear to suggest that these particular VNAR constructs, at least, are of low inherent immunogenicity.

P437 Anti-TNF α antibodies in patients with inflammatory bowel disease naive to anti-TNF therapy treated with biosimilar infliximab (CT-P13): a prospective single-centre real-life study

Abstract Background There are several tests for detecting antibodies to infliximab. The tests differ in sensitivity and therefore the detection of antibodies varies significantly between clinical trials, and less data is available for induction compared with the maintenance therapy. The aim of the study was to determine the incidence of anti-drug antibodies (ADAs) in patients during induction and maintenance therapy using the Enzyme-Linked Immunosorbent Assay (ELISA) and to analyse the risk factors for their occurrence. Methods It was a prospective single-centre study involving 84 patients with IBD during treatment with biosimilar infliximab (CT-P13) at the Tertiary IBD Center in South-eastern Poland between 2016 and 2019. All participants were naive to previous anti-TNF α therapy (80 patients). ADAs serum testing was only performed when IFX levels below 3 µg/ml were found during induction or maintenance therapy. The incidence of ADAs was analysed, and the relationship between the presence of ADAs and selected variables was assessed: gender, type of disease, immunosuppressive therapy, and undetectable drug level at week 6. The relationship between response to induction treatment and high//low ADAs titers was also compared using Fisher’s exact test. Results The incidence of ADAs in the study population was 10.7%, which is 20.4% of patients with non-therapeutic and 50% of patients with undetectable levels of IFX. The percentage of people with ADAs in the induction treatment group was 11.3% (n = 6) and in the maintenance group 3.9% (n = 3). There was no statistically significant difference in the frequency of finding ADAs in both groups (p = 0.158). In contrast, a statistically significant relationship between the undetectable level of IFX at week 6 and the presence of ADAs was confirmed, 88.9% of patients with ADAs vs. 16.0% patients without ADAs (p &amp;lt;0.001. Comparison of the relationship between response to induction treatment and high//low ADAs titers did not show a statistically significant relationship between these variables (p = 0.381). Conclusion The overall incidence of ADAs in patients treated with biosimilar infliximab (CT-P13) naive to previous anti_TNF therapy was relatively low, but in the case of undetectable levels of the drug, the phenomenon of immunogenicity was detected in half of the patients. Undetectable level of infliximab at week 6 was a risk factor for the presence of ADAs. There was no significant association between response to induction therapy and ADAs titers.