Association of adalimumab trough concentrations and treatment response in patients with juvenile idiopathic arthritis.

OBJECTIVE: The objective of this study was to assess the relationship between adalimumab trough concentrations and treatment response in paediatric patients with JIA. METHODS: This was a monocentric cohort study of JIA patients treated with adalimumab. Clinical data and samples were collected during routine follow-up. Adalimumab trough concentrations were quantified by a novel liquid chromatography-tandem mass spectrometry assay. Anti-adalimumab antibodies were measured in samples with trough concentrations of ≤5mg/l. Disease activity was evaluated using the clinical Juvenile Arthritis DAS with 71-joint count (cJADAS71). Response to adalimumab was defined according to recent international treat-to-target guidelines. RESULTS: A total of 35 adalimumab trough samples were available from 34 paediatric patients with JIA. Although there was no significant difference in adalimumab dose, trough concentrations were significantly lower in patients with secondary failure [median 1.0 mg/l; interquartile range (IQR) 1.0-5.3] compared with patients with primary failure (median 13.97 mg/l; IQR 11.81-16.67) or an adequate response (median 14.94 mg/l; IQR 10.31-16.19) to adalimumab. CONCLUSION: Adalimumab trough concentrations were significantly lower in JIA patients with secondary failure compared with patients with primary failure or an adequate response to adalimumab. Our results suggest that trough concentration measurements could identify JIA patients who require increased adalimumab doses to achieve or maintain therapeutic drug concentrations.

Higher Maintenance Adalimumab Trough Levels are Associated With Achievement of Advanced Remission Targets in Patients With Inflammatory Bowel Disease.

BACKGROUND: Biomarker normalization and endoscopic remission are superior to clinical remission in achieving improved long-term clinical outcomes in patients with inflammatory bowel diseases. GOAL: To study whether higher maintenance adalimumab levels are associated with clinical remission, biomarker normalization, and endoscopic remission. STUDY: Data were collected retrospectively from the patients' medical records. We defined clinical remission as a Harvey Bradshaw Index ≤5 or a partial Mayo score ≤2 for Crohn's disease (CD) and ulcerative colitis (UC), respectively, biomarker normalization as a C-reactive protein <0.5 mg/dL and/or calprotectin <250 (mg/kg), endoscopic remission as a (simple endoscopic score-CD) ≤3/4 for ileal/extensive CD, respectively, or an endoscopic Mayo score ≤1 for UC, and deep remission as the combination of clinical and endoscopic remission with normal biomarkers. RESULTS: Ninety-seven patients were included (82 CD and 15 UC). Patients who achieved clinical remission, biomarker normalization, or endoscopic remission had higher serum trough adalimumab levels compared with patients not in remission [mean (M)±standard error (SE)=8.98±0.78 vs. 5.92±0.96 µg/mL; P=0.016, 9.38±0.85 vs. 5.48±0.87 µg/mL; P=0.002; 9.13±0.88 vs. 6.02±0.77 µg/mL; P=0.019, respectively]. Receiver-operating curve analysis showed that an adalimumab level of ≥8.25 µg/mL was associated with deep remission (sensitivity 84%, specificity 70%, area under the curve 0.775; P<0.001). CONCLUSION: Clinical remission, biomarker normalization, and endoscopic remission are positively associated with adalimumab trough levels. Adalimumab level of ≥8.25 µg/mL is associated with deep remission. This study provides additional data to guide therapeutic drug monitoring with adalimumab.

Adalimumab Concentration Changes After Dose Escalation in Inflammatory Bowel Disease.

BACKGROUND: Dose escalation of adalimumab (ADA) for loss or response in inflammatory bowel disease (IBD) is a common practice. Recent data suggest improved outcomes with an ADA concentration of 12 mcg/mL, but limited data are available on the ability to achieve a target concentration. The aim of this study was to determine the expected change in serum ADA concentration after a dose escalation performed every 7 days in patients with IBD. METHODS: A retrospective cohort of patients with IBD receiving ADA was divided into every fourteen-day dosing, every 7-day dosing, and dose escalation (ie, q14 to q7 day dosing). The primary outcome was the change in ADA concentration. Multiple logistic regression was performed to identify predictors of achieving a target ADA concentration of ≥12 mcg/mL. RESULTS: Overall, 380 patients were identified, of whom 200 underwent dose escalation, 100 remained on q14 days dosing, and 80 were maintained on q7 day dosing. After dose escalation, the mean ADA concentration increased by 5.5 mcg/mL (P < 0.0001). After dose escalation, a significant proportion of patients achieved an ADA concentration ≥12 mcg/mL (P = 0.0019), as well as clinical remission (P = 0.0053). Based on multiple logistic regression, age of <46 years [odds ratio (OR): 2.4; 95% confidence interval (CI): 1.3, 4.6; P < 0.01], body mass index of <29 (OR: 0.21; 95% CI: 0.1, 0.5; P < 0.0001), and initial ADA concentration of ≥3.0 mcg/mL were found to be associated with a target ADA concentration ≥12 mcg/mL (OR: 4.76; 95% CI: 2.3, 9.7; P < 0.0001). CONCLUSIONS: The average expected increase in serum ADA concentration after dose escalation from q14 to q7 days was 5.5 mcg/mL. The initial ADA concentration, age, and body mass index may influence the ability to achieve a target ADA concentration after dose escalation.

No Difference of Adalimumab Pharmacokinetics When Dosed at 40 mg Every Week or 80 mg Every Other Week in IBD Patients in Clinical Remission After Adalimumab Dose Intensification.

INTRODUCTION: The pharmacokinetic equivalence of dose intensification with adalimumab (ADA) 80 mg every other week (EOW) compared to weekly 40 mg has only been supported by modeling systems. AIM OF THE STUDY: To compare the trough levels of ADA (TLA) and the occurrence of anti-ADA antibodies (AAA) between these two treatment regimens. PATIENTS AND METHODS: This was a prospective study including all consecutive patients with inflammatory bowel disease (IBD) who had reached a longstanding and deep remission under treatment with ADA 40 mg once a week. In these patients, the ADA regimen was changed from 40 mg/week to 80 mg EOW. TLA and AAA levels using a drug-tolerant assay were monitored before and ten weeks after from the change in the ADA regimen and the results compared by a Wilcoxon paired test. RESULTS: Sixty-two patients (60% CD, mean age 35 years) were included. Before and ten weeks after the changes of ADA regimen, the median TLA were (6.9 µg/mL versus 7.0 µg/mL, respectively; P = 0.34) and the AAA levels (3.4 µg/ml-eq versus 3.0 µg/ml-eq, respectively; P = 0.25.) were quite similar. Likewise, quartiles of TLA (Kendall test r = 0.91; P < 0.001) and AAA (r = 0.78; P < 0.001) did not differ before and after ADA regimen. When stratifying all the patients into 4 groups based on drug/antibody levels (immunogenic, subtherapeutic, therapeutic, or supratherapeutic), no patient needed for returning to the previous weekly regimen. In terms of acceptability, more than 60% of patients preferred an injection EOW compared once a week. CONCLUSIONS: In IBD patients who achieved a deep clinical remission under ADA 40 mg once a week, the pharmacokinetic of ADA was similar when ADA regimen was changed to 80 mg EOW. Given the patient's preference for the latter regimen, a modification of injection regimen should be systematically proposed.

Proactive Monitoring of Adalimumab Trough Concentration Associated With Increased Clinical Remission in Children With Crohn's Disease Compared With Reactive Monitoring.

BACKGROUND & AIMS: Proactive monitoring of drug trough concentrations and antibodies against drugs might help determine whether patients are likely to respond to treatment and increase efficacy. We investigated whether proactive drug monitoring is associated with higher rates of clinical remission in pediatric patients with Crohn's disease (CD). METHODS: We performed a nonblinded, randomized controlled trial of 78 children with CD (6-18 years old; 29% female; mean age, 14.3 ± 2.6 years) who had not received prior treatment with a biologic agent but had responded to adalimumab induction therapy, under scheduled monitoring of clinical and biologic measures (based on clinical factors and levels of C-reactive protein and fecal calprotectin), at pediatric gastroenterology units in Israel from July 2015 through December 2018. The patients were randomly assigned to groups that received proactive monitoring (trough concentrations measured at weeks 4 and 8 and then every 8 weeks until week 72, n = 38) or reactive monitoring (physicians were informed of trough concentrations after loss of response, n = 40). In both groups, doses and intervals of adalimumab were adjusted to achieve trough concentrations of 5 µg/mL. The primary endpoint was sustained corticosteroid-free clinical remission at all visits (week 8 through week 72). RESULTS: The primary endpoint was achieved by 31 children (82%) in the proactive group and 19 children (48%) in the reactive group (P = .002). Sixteen patients in the proactive monitoring group (42%) achieved a composite outcome of sustained corticosteroid-free remission, C-reactive protein ≤0.5 mg/dL, and level of fecal calprotectin ≤150 µg/g compared with 5 patients in the reactive monitoring group (12%) (P = .003). By week 72 of treatment, 33 patients in the proactive monitoring group had received adalimumab intensification (87%) compared with 24 patients in the reactive monitoring group (60%) (P = .001). CONCLUSIONS: In a randomized controlled trial of pediatric patients with CD, we found that proactive monitoring of adalimumab trough concentrations and adjustment of doses and intervals resulted in significantly higher rates corticosteroid-free clinical remission than reactive monitoring (measuring trough concentration after loss of response). Clinicaltrials.gov no.: NCT02256462.

Comparative nonclinical assessments of the biosimilar PF-06410293 and originator adalimumab.

Adalimumab, a recombinant fully human monoclonal antibody targeting tumor necrosis factor (TNF), is approved in the United States and Europe to treat various inflammatory and autoimmune indications. Biosimilars are approved biologics highly similar, but not identical, to approved biotherapeutics. To support clinical development of PF-06410293, an adalimumab biosimilar, nonclinical studies evaluated the structural, functional, toxicologic, and toxicokinetic similarity to originator adalimumab sourced from the United States (adalimumab-US) and European Union (adalimumab-EU). Structural similarity was assessed by peptide mapping. Biologic activity was measured via inhibition of TNF-induced apoptosis and Fc-based functionality assessments. In vivo nonclinical similarity was evaluated in a toxicity study in cynomolgus monkeys administered subcutaneous PF-06410293 or adalimumab-EU (0 or 157 mg/kg/week). Peptide mapping demonstrated PF-06410293, adalimumab-US, and adalimumab-EU had identical amino acid sequences. Comparative functional and binding assessments were similar. Effects of PF-06410293 and adalimumab-EU were similar and limited to pharmacologically mediated decreased cellularity of lymphoid follicles and germinal centers in spleen. Toxicokinetics were similar; maximum plasma concentration and area-under-the-concentration-time curve ratio of PF-06410293:adalimumab-EU ranged from 1.0 to 1.2. These studies supported PF-06410293 entry into clinical development. Many regulatory agencies now only request nonclinical in vivo testing if there is residual uncertainty regarding biosimilarity after in vitro analytical studies.

Methotrexate Reduces the Clearance of Adalimumab by Increasing the Concentration of Neonatal Fc Receptor in Tissues.

PURPOSE: Although pharmacokinetic (PK) interaction effects of methotrexate (MTX) on adalimumab have been found, the mechanism of these effects is still unclear. In this work, effects of MTX on the concentration of neonatal Fc receptor (FcRn) and the role of FcRn in the interaction between MTX and adalimumab were investigated. METHODS: The experiment was performed in rats whose FcRn had normal physiological function and also in rats whose FcRn was blocked with FcRn antibody. Rats were randomly assigned to receive placebo or 0.2 mg/kg MTX orally every week while taking one abdominal subcutaneous injection of 0.5 mg/kg adalimumab. The FcRn concentration in tissues and the PK parameters of adalimumab were compared between MTX-treated and placebo groups. RESULTS: In rats with normally functioning FcRn, the concentrations of FcRn were significantly increased in the liver (F=105.5, p=0.000) and kidney (F=996.312, p=0.000) after treatment with MTX, and the clearance (CL/F) of adalimumab was decreased accordingly (F=4.423, p=0.048). However, in rats injected with FcRn antibody, the concentrations of FcRn in MTX-treated rats were close to that of the placebo rats in the tissues of the liver (F=1.279, p=0.268) and kidney (F=0.661, p=0.424). The CL/F of adalimumab in rats was also not affected by MTX (F=0.002, p=0.961). CONCLUSIONS: FcRn may play a vital role in the interaction between adalimumab and MTX.

High anti-TNF alfa drugs trough levels are not associated with the occurrence of adverse events in patients with inflammatory bowel disease.

Objectives: Up to 40% of inflammatory bowel disease (IBD) patients treated with anti-TNF drugs lose response within 1 year of treatment, therefore requiring drug optimization. Although higher drug trough levels (TLs) are associated with sustained clinical outcomes, there are concerns that they may be associated with a higher risk of adverse events (AEs). The aim was to evaluate the presence of a possible association between drug TLs and the occurrence of AEs in IBD patients treated with anti-TNF drugs.Methods: We retrospectively studied a cohort of 113 IBD patients treated with adalimumab or infliximab, of whom 27 were in combination therapy with immunosuppressants. TLs were measured using a homogeneous mobility shift assay.Results: During a median follow-up of 16 months (range 1-144), we observed 103 AEs occurring in 58 patients. We found no statistically significant difference (p = .21) in median TLs between patients who did 6.7 mcg/mL; range 0.0-36.2) or did not (7.7 mcg/mL; range 0.0-20.7) experience an AE. No difference was observed in the rate of AEs between patients in mono- or combination therapy (p = .38), as well as between elderly (i.e., >65 years) and younger patients (p = .32). Considering a TL cutoff of 7 mcg/mL for infliximab and 12 mcg/mL for adalimumab, or even double these TL values, we observed no statistically significant difference in the rate of AEs occurrence.Conclusion: Our study suggests that, when clinically required, anti-TNF drug dosage may be increased without particular concerns regarding the risk of AEs occurrence in IBD patients, even in patients on combination therapy and elderly ones.

Correlation Between Anti-TNF Serum Levels and Endoscopic Inflammation in Inflammatory Bowel Disease Patients.

OBJECTIVES: (a) To evaluate the diagnostic accuracy of anti-TNF trough levels to predict mucosal healing in inflammatory bowel disease (IBD); (b) to determine the best cut-off point to predict mucosal healing in IBD patients treated with anti-TNF. METHODS: This is a multicenter, prospective study. IBD patients under anti-TNF treatment for at least 6 months that had to undergo an endoscopy were included. Mucosal healing was defined as: Simple endoscopic score for Crohn's Disease < 3 for Crohn's disease (CD), Rutgeerts score < i2 for CD in postoperative setting, or Mayo endoscopic score ≤ 1 for ulcerative colitis (UC). Anti-TNF concentrations were measured using SMART ELISAs at trough. RESULTS: A total of 182 patients were included. Anti-TNF trough levels were significantly higher among patients that had mucosal healing than among those who did not. The area under the curve of infliximab for mucosal healing was 0.63 (best cutoff value 3.4 µg/mL), and for adalimumab 0.60 (best cutoff value 7.2 µg/mL). In the multivariate analysis, having anti-TNF drug levels above the cutoff values [odds ratio (OR) 3.1]) and having UC instead of CD (OR 4) were associated with a higher probability of having mucosal healing. Additionally, the need for an escalated dosage (OR 0.2) and current smoking habit (OR 0.2) were also associated with a lower probability of mucosal healing. CONCLUSIONS: There was an association between anti-TNF trough levels and mucosal healing in IBD patients; however, the accuracy of the determination of infliximab and adalimumab concentrations able to predict mucosal healing was suboptimal.

Demonstration of functional similarity of a biosimilar adalimumab SB5 to Humira®.

A biosimilar is a biological medicinal product that is highly similar to an authorized biological product in terms of quality, biological activity, safety and efficacy. SB5 was developed by Samsung Bioepis as a biosimilar referencing adalimumab, and was authorized by the European Commission (EC) in August 2017 (Imraldi®). Extensive characterization studies were performed to demonstrate functional similarity of SB5 to reference adalimumab (Humira®, AbbVie Inc. and AbbVie Deutschland GmbH & Co. KG). SB5 and Humira® showed highly similar soluble TNF-α binding and neutralizing activity, as well as transmembrane TNF-α binding activity and reverse signaling induced in the membrane TNF-α expressing cell line. Both products exhibited similar binding of the Fc gamma receptors and Fc-related effector functions such as antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC). In addition, additional mechanisms of action induced by TNF-α, such as cytokine release and expression of adhesion molecules, were analyzed and shown to be similar between SB5 and Humira®. Taken together, our results demonstrate that SB5 and Humira® are highly similar in terms of their functional characteristics.

Validation of a population pharmacokinetic model of adalimumab in a cohort of patients with inflammatory bowel disease.

BACKGROUND: therapeutic monitoring of anti-TNF drugs and anti-drug antibody levels are useful for clinical decision-making, via the rationalization and optimization of the use of anti-TNF treatments. The objective of the present study was to validate the model of Ternant et al., in a cohort of patients with inflammatory bowel diseases (IBD). This model was originally established for patients with rheumatoid arthritis and was used in this study to optimize the adalimumab (ADA) dose and predict ADA trough levels (ATL). METHODS: this study used concentration data points from 30 IBD patients who received ADA treatment between 2014 and 2015. A goodness-of-fit of the model was determined by evaluating the relationship between the observed ATL values and population model-predicted values (PRED) or individual model-predicted values (IPRED). RESULTS: a total of 51 ADA concentration points were analyzed. The bias of the model was 2.39 (95% CI, 1.63-3.15) for PRED and 0.63 (95% CI, 0.23-1.03) for IPRED. The precision was 3.57 (95% CI, 2.90-4.13) and 1.53 (95% CI, 1.22-1.80), respectively. CONCLUSIONS: therapeutic drug monitoring involving ATL may allow the optimization of the treatment of IBD patients. The validation results of the phamacokinectic (PK) model for ADA in IBD patients are inadequate. However, additional studies will strengthen the bias and precision of the model.

Clinical and Pharmacokinetic Factors Associated With Adalimumab-Induced Mucosal Healing in Patients With Crohn's Disease.

BACKGROUND & AIMS: We previously reported results from a prospective randomized controlled trial comparing the efficacy of adalimumab monotherapy versus combination with azathioprine for patients with Crohn's disease (CD) who were naive to biologics and thiopurines. We performed a subanalysis of data from this study to evaluate factors associated with endoscopic response and mucosal healing in study participants. METHODS: We compared simple endoscopic scores for CD between patients with moderate to severe active CD randomly assigned groups that received adalimumab monotherapy (n = 85) or adalimumab in combination with azathioprine (n = 91), from June 2011 to June 2014 in Japan. We evaluated associations of simple endoscopic scores for CD with clinical factors and trough levels of adalimumab. Ultimately, 135 patients at Week 26 and 139 patients at Week 52 from 44 referral sites were analyzed for the present investigation. RESULTS: The odds for endoscopic response were significantly higher in the combination group than in the monotherapy group at Week 26 (odds ratio [OR], 2.12; 95% confidence interval [CI], 1.04-4.32) but not at Week 52 (OR, 1.50; 95% CI, 0.77-2.94). The odds of mucosal healing did not differ significantly between groups at Weeks 26 or 52. Simple endoscopic scores for CD at Week 0 was significantly associated with mucosal healing at Week 26 (OR, 0.80; 95% CI, 0.72-0.90) and at Week 52 (OR, 0.91; 95% CI, 0.84-0.99). Higher adalimumab trough level at Week 26 associated with mucosal healing at Week 52 (OR, 1.34; 95% CI, 1.14-1.58; P for trend = .001) and was significantly higher in patients with endoscopic response than in patients without endoscopic response at Weeks 26 and 52 (P < .001). CONCLUSIONS: In a post hoc analysis of data from a randomized controlled trial of patients with moderate to severe CD, we found that adalimumab in combination with azathioprine increased trough levels of adalimumab. Higher trough levels of adalimumab associated with endoscopic response and mucosal healing at Weeks 26 and 52. UMIN registration No: 000005146.

Phase III randomized study of the proposed adalimumab biosimilar GP2017 in psoriasis: impact of multiple switches.

BACKGROUND: Adalimumab is used to treat several inflammatory diseases, including plaque psoriasis. GP2017 is a proposed adalimumab biosimilar. OBJECTIVES: To assess the impact of multiple switches between GP2017 and reference adalimumab (ref-ADMB) following the demonstration of equivalent efficacy and similar safety and immunogenicity, in adult patients with active, clinically stable, moderate-to-severe plaque psoriasis. METHODS: This 51-week double-blinded, phase III study randomly assigned patients to GP2017 (n = 231) or ref-ADMB (n = 234) 80 mg subcutaneously at week 0, then 40 mg biweekly from week 1. At week 17, patients were rerandomized to switch (n = 126) or continue (n = 253) treatment. The primary end point was patients achieving ≥ 75% improvement in Psoriasis Area and Severity Index (PASI 75) at week 16, with equivalence confirmed if the 95% confidence interval (CI) for the difference in PASI 75 between treatments was ± 18%. The key secondary end point was the change from baseline to week 16 in continuous PASI. Other end points were PASI over time; PASI 50, 75, 90 and100; pharmacokinetics; safety; tolerability and immunogenicity for the switched and continued treatment groups. RESULTS: Equivalent efficacy between GP2017 and ref-ADMB was confirmed for the primary (66·8% and 65·0%, respectively; 95% CI -7·46 to 11·15) and key secondary end points (-60·7% and -61·5%, respectively; 95% CI -3·15 to 4·84). PASI improved over time and was similar between treatment groups at week 16, and the switched and continued groups from weeks 17 to 51. There were no relevant safety or immunogenicity differences between GP2017 and ref-ADMB at week 16, or the switched and continued groups from weeks 17 to 51. No hypersensitivity to adalimumab was reported upon switching. CONCLUSIONS: Following the demonstration of GP2017 biosimilarity to ref-ADMB, switching up to four times between GP2017 and ref-ADMB had no detectable impact on efficacy, safety or immunogenicity.

Explaining Interpatient Variability in Adalimumab Pharmacokinetics in Patients With Crohn's Disease.

BACKGROUND: A significant proportion of patients with Crohn's disease (CD) require dose escalation or fail adalimumab (ADL) therapy over time. ADL, a monoclonal antibody directed against tumor necrosis factor, is approved for treatment of CD. Understanding pharmacokinetics (PK) of ADL is essential to optimize individual dosing in daily practice. The aim of this study was to evaluate PK of ADL in patients with CD and to identify factors that influence PK of ADL. METHODS: In a retrospective cohort study, the authors reviewed the charts of 96 patients with CD receiving ADL induction and maintenance treatment. This patient cohort was used for external validation of population pharmacokinetic models of ADL available from literature. In addition, a novel population PK model was developed using nonlinear mixed-effects modeling. RESULTS: None of the literature models properly described the PK of ADL in our cohort. Therefore, a novel population pharmacokinetic model was developed. Clearance of ADL increased 4-fold in the presence of anti-ADL antibodies. Patients who received ADL every week had a 40% higher clearance compared with patients receiving ADL every other week. CONCLUSIONS: Clearance of ADL increased in the presence of anti-ADL antibodies and was associated with weekly ADL administrations. In clinical practice, the decision to intensify ADL treatment to weekly administrations is primarily based on disease activity. Increased disease activity may be the result of lower drug concentrations due to higher clearance. However, increased disease activity may also increase clearance due to increased target engagement. The causal relationship between these factors remains to be elucidated.

Comparison of Point-of-Care and Classical Immunoassays for the Monitoring Infliximab and Antibodies Against Infliximab in IBD.

OBJECTIVE: The primary objective is to assess whether the POC assays to measure infliximab residual trough level in the serum of IBD patients were non-inferior to the ELISA techniques available on the market, and to determine which of them was the most robust. The second is to compare three different ELISA kits for monitoring anti-infliximab antibodies (ATI). METHODS: The assays were carried out on patients' sera using four ELISA kits from four different suppliers (three with a monoclonal antibody and one polyclonal) and two rapid techniques provided by BÜHLMANN (Quantum Blue®) and R-Biopharm (Ridaquick) for monitoring infliximab levels. ATI were measured by three ELISA sets (Grifols, Theradiag, and R-Biopharm) which have different positivity limits and different units. RESULTS: We measured infliximab residual level and ATI in the serum of 90 IBD patients (85 treated with infliximab and five with adalimumab). All of the infliximab assays were very well correlated when analyzed with Spearman nonparametric correlation (0.93 ≤ r ≤ 0.99), and the two POC assays were also excellently correlated (r = 0.98). The ATI monitoring kits revealed a correlation ranging from 0.73 to 0.96 when comparing positive and negative patients. When normalizing the quantitative values between the different ELISA tests (expressed arbitrarily by using multiples of the positivity limits defined by each supplier), the Spearman r coefficient ranged from 0.81 to 0.93. CONCLUSION: The available evidence allows us to conclude that all of the infliximab monitoring assays correlate well and may be used for IFX monitoring; albeit variations in measured IFX concentration among different assays remain present, these assays could be interchangeable. The ATI monitoring techniques are all capable of detecting ATI-positive patients, but because of the difference in the positivity limits and the measurement units, it is better to follow a patient rate with one definite kit.

Pharmacokinetic and pharmacodynamic model for analysis of adalimumab administered for Crohn's disease.

Adalimumab (ADA) is used as a therapeutic agent for Crohn's disease (CD). Although the dosage regimen has been established through clinical trial experience, it has not been analysed theoretically. The present study analysed of sequential changes in the Crohn's disease activity index (CDAI) after repeated administrations of adalimumab using a pharmacokinetic and pharmacodynamic model. In addition, we analysed the validity of the dosage regimen, and the potential efficacy gained by increasing the dose and reducing the interval of administration. The sequential changes in CDAI values obtained with our model were in good agreement with observed CDAI values, which is considered to show the validity of our analysis. We consider that our results showed the importance of a loading dose of adalimumab to obtain remission in an early stage of active CD. In addition, we showed that patients who have an incomplete response to adalimumab can obtain similar efficacy from increasing the dose and reducing the dose interval. In conclusion, our results showed that the present model may be applied to predict the CDAI values of adalimumab for CD. They indicate the validity of the dosage regimen, as well as the efficacy of increasing the dose and reducing the dose interval.

Sustained secretion of anti-tumor necrosis factor α monoclonal antibody from ex vivo genetically engineered dermal tissue demonstrates therapeutic activity in mouse model of rheumatoid arthritis.

BACKGROUND: Rheumatoid arthritis (RA) is a symmetric inflammatory polyarthritis associated with high concentrations of pro-inflammatory, cytokines including tumor necrosis factor (TNF)-α. Adalimumab is a monoclonal antibody (mAb) that binds TNF-α, and is widely used to treat RA. Despite its proven clinical efficacy, adalimumab and other therapeutic mAbs have disadvantages, including the requirement for repeated bolus injections and the appearance of treatment limiting anti-drug antibodies. To address these issues, we have developed an innovative ex vivo gene therapy approach, termed transduced autologous restorative gene therapy (TARGT), to produce and secrete adalimumab for the treatment of RA. METHODS: Helper-dependent (HD) adenovirus vector containing adalimumab light and heavy chain coding sequences was used to transduce microdermal tissues and cells of human and mouse origin ex vivo, rendering sustained secretion of active adalimumab. The genetically engineered tissues were subsequently implanted in a mouse model of RA. RESULTS: Transduced human microdermal tissues implanted in SCID mice demonstrated 49 days of secretion of active adalimumab in the blood, at levels of tens of microgram per milliliter. In addition, transduced autologous dermal cells were implanted in the RA mouse model and demonstrated statistically significant amelioration in RA symptoms compared to naïve cell implantation and were similar to recombinant adalimumab bolus injections. CONCLUSIONS: The results of the present study report microdermal tissues engineered to secrete active adalimumab as a proof of concept for sustained secretion of antibody from the novel ex vivo gene therapy TARGT platform. This technology may now be applied to a range of antibodies for the therapy of other diseases.

Pharmacokinetics, safety, tolerability and immunogenicity of FKB327, a new biosimilar medicine of adalimumab/Humira, in healthy subjects.

AIMS: To compare the pharmacokinetics, safety, tolerability and immunogenicity of FKB327, a biosimilar of adalimumab, with European Union (EU)-approved Humira and US-licensed Humira after single subcutaneous doses in healthy subjects. METHODS: In a randomized, double-blind, parallel-group study, 180 healthy subjects received by subcutaneous injection 40 mg of EU-Humira, or US-Humira, or FKB327, in a 1:1:1 ratio, stratified by bodyweight. Pharmacokinetics, local tolerability, immunogenicity, adverse events, vital signs, electrocardiography and laboratory safety tests were assessed prior to and up to 1536 h after treatment. RESULTS: The pharmacokinetics of FKB327 were similar to those of both EU- and US-Humira. The 90% confidence interval for the ratios of AUC0-t , AUC0-inf , and Cmax geometric means were in the acceptance range for bioequivalence of 0.80-1.25 for all three pairwise comparisons by analysis of covariance with baseline characteristics age, body weight and (for Cmax only) sex as covariates. Tolerability of all three treatments was equally acceptable, and there were no differences in safety profile or immunogenicity among the three treatments. Overall, antidrug antibodies were detected in approximately 70% of subjects who received each treatment; higher titres were associated with faster elimination of adalimumab. CONCLUSIONS: The study demonstrated pharmacokinetic similarity of FKB327 with EU- and US-Humira. FKB327 was well tolerated by healthy subjects, with adverse effects similar to Humira. If clinical similarity to Humira, including efficacy, can be shown in patients, FKB327 will meet the criteria for biosimilarity to Humira.

Determination of adalimumab and etanercept trough levels and drug antibodies in long-term psoriasis treatment: a single-centre cohort study.

BACKGROUND: An algorithm based on measurement of a serum tumour necrosis factor antagonists (anti-TNF) and antidrug antibodies (ADA) has been proposed previously to guide dose escalation or therapy switching in the early (i.e. the first months of) treatment of psoriasis by anti-TNF. In long-term treatment of responding patients with psoriasis, it is usual to empirically reduce standard doses of anti-TNF to reduce exposure while maintaining clinical response. The relationship between serum anti-TNF, ADA levels and clinical efficacy in long-term treated patients with psoriasis has not yet been determined, so the potential role of these parameters in guiding dose escalation in this scenario is unknown. AIMS: To evaluate the relationship between drug/ADA levels and clinical efficacy in a group of patients with psoriasis undergoing long-term treatment with adalimumab or etanercept. METHODS: This was a single-centre, prospective, cohort study of patients with psoriasis receiving adalimumab or etanercept for a minimum of 48 weeks. All patients were started on the standard dose, but some adalimumab users had a reduced frequency of administration. Clinical efficacy was measured using the Psoriasis Area and Severity Index. Serum concentrations were measured by ELISA. Clinical assessment and blood sample collection were carried out simultaneously within 24 h before the next drug administration. RESULTS: In total, 21 patients were enrolled (67 simultaneous clinical and serum determinations: 38 receiving adalimumab, 29 receiving etanercept). We did not find any association between serum anti-TNF levels and clinical response. None of the patients developed ADA. CONCLUSIONS: ADA and anti-TNF levels are not related to clinical effectiveness in patients with psoriasis undergoing long-term treatment with adalimumab or etanercept.

A randomized phase I comparative pharmacokinetic study comparing SB5 with reference adalimumab in healthy volunteers.

WHAT IS KNOWN AND OBJECTIVE: SB5 is a biosimilar to the reference adalimumab (ADL) currently in development. The primary study objective was to demonstrate pharmacokinetic (PK) equivalence of SB5 to European Union-sourced adalimumab (EU-ADL), and United States-sourced adalimumab (US-ADL) in healthy subjects. Safety, tolerability and immunogenicity were also assessed as secondary objectives. METHODS: In this phase I, single-blind trial, 189 healthy volunteers were randomized to a single 40 mg dose of SB5, EU-ADL or US-ADL and PK was evaluated for 71 days afterwards. Serum adalimumab concentrations were measured using an enzyme-linked immunosorbent assay (ELISA) test. PK parameters were calculated based on actual sampling times relative to dosing and non-compartmental analysis methods, and equivalence was determined using predefined margins of 0.8-1.25. RESULTS AND DISCUSSION: Baseline characteristics and demographics were comparable between the three groups. Mean values of area under the concentration-time curve from time zero to infinity (AUCinf ), maximum serum concentration (Cmax ) and AUC from time zero to the last quantifiable concentration (AUClast ) were similar between groups, and 90% confidence interval for these parameters were within the predefined equivalence margins for all pairwise comparisons. No discontinuations due to treatment-emergent adverse events (TEAEs) or deaths were reported. Number and kind of TEAEs were comparable between the three groups and considered mild to moderate. The incidence of subjects with antidrug antibodies (ADA) and the overall incidence of neutralizing antibody (NAb) were comparable across the three groups. WHAT IS NEW AND CONCLUSION: The PK of SB5 was equivalent to that of EU-ADL and US-ADL. SB5 was well tolerated with similar safety and immunogenicity profile to EU-ADL and US-ADL.