Lower Serologic Response to COVID-19 mRNA Vaccine in Patients With Inflammatory Bowel Diseases Treated With Anti-TNFα.

BACKGROUND & AIM: Patients with inflammatory bowel diseases (IBD), specifically those treated with anti-tumor necrosis factor (TNF)α biologics, are at high risk for vaccine-preventable infections. Their ability to mount adequate vaccine responses is unclear. The aim of the study was to assess serologic responses to messenger RNA-Coronavirus Disease 2019 vaccine, and safety profile, in patients with IBD stratified according to therapy, compared with healthy controls (HCs). METHODS: Prospective, controlled, multicenter Israeli study. Subjects enrolled received 2 BNT162b2 (Pfizer/BioNTech) doses. Anti-spike antibody levels and functional activity, anti-TNFα levels and adverse events (AEs) were detected longitudinally. RESULTS: Overall, 258 subjects: 185 IBD (67 treated with anti-TNFα, 118 non-anti-TNFα), and 73 HCs. After the first vaccine dose, all HCs were seropositive, whereas ∼7% of patients with IBD, regardless of treatment, remained seronegative. After the second dose, all subjects were seropositive, however anti-spike levels were significantly lower in anti-TNFα treated compared with non-anti-TNFα treated patients, and HCs (both P < .001). Neutralizing and inhibitory functions were both lower in anti-TNFα treated compared with non-anti-TNFα treated patients, and HCs (P < .03; P < .0001, respectively). Anti-TNFα drug levels and vaccine responses did not affect anti-spike levels. Infection rate (∼2%) and AEs were comparable in all groups. IBD activity was unaffected by BNT162b2. CONCLUSIONS: In this prospective study in patients with IBD stratified according to treatment, all patients mounted serologic response to 2 doses of BNT162b2; however, its magnitude was significantly lower in patients treated with anti-TNFα, regardless of administration timing and drug levels. Vaccine was safe. As vaccine serologic response longevity in this group may be limited, vaccine booster dose should be considered.

Antibiotic use differentially affects the risk of anti-drug antibody formation during anti-TNFα therapy in inflammatory bowel disease patients: a report from the epi-IIRN.

OBJECTIVE: Anti-drug antibodies (ADA) to anti-tumour necrosis factor (anti-TNF) therapy drive treatment loss of response. An association between intestinal microbial composition and response to anti-TNF therapy was noted. We therefore aimed to assess the implications of antibiotic treatments on ADA formation in patients with inflammatory bowel disease (IBD). DESIGN: We analysed data from the epi-IIRN (epidemiology group of the Israeli IBD research nucleus), a nationwide registry of all patients with IBD in Israel. We included all patients treated with anti-TNF who had available ADA levels. Survival analysis with drug use as time varying covariates were used to assess the association between antibiotic use and ADA development. Next, specific pathogen and germ-free C57BL mice were treated with respective antibiotics and challenged with infliximab. ADA were assessed after 14 days. RESULTS: Among 1946 eligible patients, with a median follow-up of 651 days from initiation of therapy, 363 had positive ADA. Cox proportional hazard model demonstrated an increased risk of ADA development in patients who used cephalosporins (HR=1.97, 95% CI 1.58 to 2.44), or penicillins with ß-lactamase inhibitors (penicillin-BLI, HR=1.4, 95% CI 1.13 to 1.74), whereas a reduced risk was noted in patients treated with macrolides (HR=0.38, 95% CI 0.16 to 0.86) or fluoroquinolones (HR=0.20, 95% CI 0.12 to 0.35). In mice exposed to infliximab, significantly increased ADA production was observed in cephalosporin as compared with macrolide pretreated mice. Germ-free mice produced no ADA. CONCLUSION: ADA production is associated with the microbial composition. The risk of ADA development during anti-TNF therapy can possibly be reduced by avoidance of cephalosporins and penicillin-BLIs, or by treatment with fluoroquinolones or macrolides.

De-escalation from Dose-Intensified Anti-TNF Therapy Is Successful in the Majority of IBD Patients at 12 Months.

BACKGROUND: Data on outcomes following de-escalation of intensified anti-TNF therapy in inflammatory bowel disease (IBD) are limited and concerns about relapse limit willingness to de-escalate. AIMS: To evaluate rates of successful de-escalation at 12 months and to determine factors that may predict success. METHODS: Single-centre experience of IBD patients that were de-escalated following deep remission on dose-intensified infliximab (IFX) or adalimumab (ADA) for secondary loss of response. Patients were classified as 'successes' if remaining on reduced anti-TNF or 'failures' if requiring re-escalation, steroids, surgery or enrolment into a clinical trial at 12 months. Patient demographics, disease characteristics, biomarkers (faecal calprotectin, C-reactive protein, albumin) and anti-TNF drug levels were collected 6-monthly. RESULTS: Of 25 patients (20 CD, 5 UC), 16 (64%) were successes 12 months post-de-escalation. Median time to failure was 6 months. Six of the nine failures required anti-TNF re-escalation and three entered a clinical trial. Re-escalation recaptured response in all six patients. There was no significant difference in baseline biomarker activity between the two groups. There was no difference in infliximab levels between successes and failures at the time of de-escalation (5.5 vs. 5.3, p = 0.63) as well as 6 months (3.1 vs. 4.6, p = 0.95) and 12 months (3.2 vs. 4.5, p = 0.58) post-de-escalation. CONCLUSION: Nearly two-thirds of patients remained on reduced anti-TNF dosing 12 months after de-escalation. All patients who failed de-escalation were recaptured after dose re-escalation. De-escalation with close monitoring may be considered in patients on intensified anti-TNF therapy in sustained remission.

Long-term exposure to monoclonal anti-TNF is associated with an increased risk of lymphoma in BAFF-transgenic mice.

The impact of treatment on the risk of lymphoma in patients with rheumatoid arthritis (RA) is unclear. Here, we aimed to assess if the risk of lymphoma differs according to the type of tumor necrosis factor inhibitor (TNFi), comparing monoclonal anti-TNF antibodies to the soluble TNF receptor. We used B cell activating factor belonging to the TNF family (BAFF)-transgenic (Tg) mice as a model of autoimmunity-associated lymphoma. Six-month-old BAFF-Tg mice were treated with TNFi for 12 months. Histological examination of the spleen, assessment of the cellular composition of the spleen by flow cytometry and assessment of B cell clonality were performed at euthanasia. Crude mortality and incidence of lymphoma were significantly higher in mice treated with monoclonal anti-TNF antibodies compared to both controls and mice treated with the soluble TNF receptor, even at a high dose. Flow cytometry analysis revealed decreased splenic macrophage infiltration in mice treated with monoclonal anti-TNF antibodies. Overall, this study demonstrates, for the first time, that a very prolonged treatment with monoclonal anti-TNF antibodies increase the risk of lymphoma in B cell-driven autoimmunity. These data suggest a closer monitoring for lymphoma development in patients suffering from B cell-driven autoimmune disease with long-term exposure to monoclonal anti-TNF antibodies.

Prevalence of hepatitis B virus infection and risk of reactivation in rheumatic population undergoing biological therapy.

OBJECTIVES: Hepatitis B (HBV) is a common comorbidity among rheumatic patients. The prevalence of HBV infection and the rate of reactivation remain unclear. The literature data suggested a higher risk in chronic than in past infection. Currently, the literature data are mostly focused on anti-TNF and rituximab. This retrospective observational study aimed to analyse the prevalence of HBV infection and the risk of viral reactivation in a population of rheumatic patients undergoing anti-TNF and non-anti-TNF agents. METHODS: We analysed 1216 rheumatic patients, treated with both csDMARDs and bDMARDs between 2006 and 2017. Serologic markers for HBV (HBsAg, anti-HBs, anti-HBc) were performed prior and during biologic treatment. Patients with chronic or resolved infection were monitored every 3 months. RESULTS: The prevalence of HBV in our cohort was 15.7% (chronic infection: 0.4%, resolved infection: 12.6%, anti-HBc positivity alone: 2.6%). 12 (6.2%) out of 191 HBV infected patients experienced a reactivation. All of them showed markers of past infection. One patient experienced HBV reactivation despite lamivudine. Only one patient experienced acute hepatitis, probably due to the interruption of immunosuppressors in anticipation of surgery, not preceded by any HBV prophylactic treatment. CONCLUSIONS: HBV reactivation is a rare event in patients treated with a bDMARD and it can also occur while taking lamivudine, not only in chronic carriers (as per the literature data) but also in inactive ones. Regular screening followed by prompt treatment can prevent symptoms or complications. Due to the risk of hepatitis following the immune reconstitution, an antiviral therapy should be considered in the case of sudden discontinuation of csDMARDs or bDMARD.

Aseptic meningitis in rheumatoid arthritis after anti-TNF administration: a case-based literature review.

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by articular and extra-articular manifestations. Among extra-articular involvement, rheumatoid meningitis (RM) is a rare condition, which may exhibit variable symptoms including headache, focal and/or generalized neurologic deficits. It may develop as the preceding manifestation of RA or occur at any time of the disease course. Some drugs used for the treatment of RA may give rise to aseptic meningitis or create a tendency to infectious meningitis due to their immunosuppressive effect. All these possibilities may lead to difficulties in the differential diagnosis. Achieving a diagnosis in a short time is crucial in terms of prognosis. Here, we would like to report a case with longstanding RA manifested by left-sided weakness and seizure shortly after initiating etanercept (ETA) therapy. ETA-induced meningitis was confirmed with appropriate diagnostic tools. Our aim with this case-based review is to attract the attention of this rare condition and discuss diagnostic challenges.

Infliximab-Tumor Necrosis Factor Complexes Elicit Formation of Anti-Drug Antibodies.

BACKGROUND & AIMS: Some patients develop anti-drug antibodies (ADAs), which reduce the efficacy of infliximab, a monoclonal antibody against tumor necrosis factor (TNF), in the treatment of immune-mediated diseases, including inflammatory bowel diseases. ADAs arise inconsistently, and it is not clear what factors determine their formation. We investigated features of the immune system, the infliximab antibody, and its complex with TNF that might contribute to ADA generation. METHODS: C57BL/6 mice were given injections of infliximab and recombinant human TNF or infliximab F(ab')2 fragments. Blood samples were collected every 2-3 days for 2 weeks and weekly thereafter for up to 6 weeks; infliximab-TNF complexes and ADAs were measured by enzyme-linked immunosorbent assay (ELISA). Intestinal biopsy and blood samples were obtained from patients having endoscopy who had received infliximab therapy for inflammatory bowel diseases; infliximab-TNF complexes were measured with ELISA. Infliximab-specific plasma cells were detected in patient tissue samples by using mass cytometry. We studied activation of innate immune cells in peripheral blood mononuclear cells (PBMCs) from healthy donors incubated with infliximab or infliximab-TNF complexes; toll-like receptors (TLRs) were blocked with antibodies, endocytosis was blocked with the inhibitor PitStop2, and cytokine expression was measured by real-time polymerase chain reaction and ELISAs. Uptake of infliximab and infliximab-TNF complexes by THP-1 cells was measured with confocal microscopy. RESULTS: Mice given increasing doses of infliximab produced increasing levels of ADAs. Blood samples from mice given injections of human TNF and infliximab contained infliximab-TNF complexes; complex formation was associated with ADA formation with an area under the curve of 0.944 (95% confidence interval, 0.851-1.000; P = .003). Intestinal tissues from patients, but not blood samples, contained infliximab-TNF complexes and infliximab-specific plasma cells. Incubation of PBMCs with infliximab-TNF complexes resulted in a 4.74-fold increase in level of interleukin (IL) 1ß (IL1B) messenger RNA (P for comparison = .005), increased IL1B protein secretion, and a 2.69-fold increase in the expression of TNF messenger RNA (P for comparison = 0.013) compared with control PBMCs. Infliximab reduced only IL1B and TNF expression. Antibodies against TLR2 or TLR4 did not block the increases in IL1B or TNF expression, but endocytosis was required. THP-1 cells endocytosed higher levels of infliximab-TNF complexes than infliximab alone. CONCLUSIONS: In mice, we found ADA formation to increase with dose of infliximab given and concentration of infliximab-TNF complexes detected in blood. Based on studies of human intestinal tissues and blood samples, we propose that infliximab-TNF complexes formed in the intestine are endocytosed by and activate innate immune cells, which increase expression of IL1B and TNF and production of antibodies against the drug complex. It is therefore important to optimize the infliximab dose to a level that is effective but does not activate an innate immune response against the drug-TNF complex.

Therapeutic drug monitoring of adalimumab in RA: no predictive value of adalimumab serum levels and anti-adalimumab antibodies for prediction of response to the next bDMARD.

BACKGROUND: After adalimumab treatment failure, tumour necrosis factor inhibition (TNFi) and non-TNFi biological disease-modifying anti-rheumatic drugs (bDMARDs) are equally viable options on a group level as subsequent treatment in rheumatoid arthritis (RA) based on the current best evidence synthesis. However, preliminary data suggest that anti-adalimumab antibodies (anti-drug antibodies, ADA) and adalimumab serum levels (ADL) during treatment predict response to a TNFi as subsequent treatment. OBJECTIVE: To validate the association of presence of ADA and/or low ADL with response to a subsequent TNFi bDMARD or non-TNFi bDMARD. Sub-analyses were performed for primary and secondary non-responders. METHODS: A diagnostic test accuracy retrospective cohort study was done in consenting RA patients who discontinued adalimumab after >3 months of treatment due to inefficacy and started another bDMARD. Inclusion criteria included the availability of (random timed) serum samples between ≥8 weeks after start and ≤2 weeks after discontinuation of adalimumab, and clinical outcome measurements Disease Activity Score in 28 joints - C-reactive protein (DAS28-CRP) between 3 to 6 months after treatment switch. Test characteristics for EULAR (European League Against Rheumatism) good response (DAS28-CRP based) after treatment with the next (non-)TNFi bDMARD were assessed using area under the receiver operating characteristic and sensitivity/specificity. RESULTS: 137 patients were included. ADA presence was not predictive for response in switchers to a TNFi (sensitivity/specificity 18%/75%) or a non-TNFi (sensitivity/specificity 33%/70%). The same was true for ADL levels in patients that switched to a TNFi (sensitivity/specificity 50%/52%) and patients that switched to a non-TNFi (sensitivity/specificity 32%/69%). Predictive value of ADA and ADL were similar for both primary and secondary non-responders to adalimumab. CONCLUSIONS: In contrast to earlier research, we could not find predictive value for response to a second TNFi or non-TNFi for either ADA or random timed ADL.

The Laboratory Role in anti-TNF Biological Therapy Era.

Along years, the advent of biological therapy widely modified treatment of rheumatic diseases and other disorders. However, many agents may elicit in anti-drug antibodies (ADAbs) upon consecutive infusions, with a loss of response. For the right strategy of a personalized medicine, the therapeutic monitoring of TNF-α inhibitors and ADAbs represents an important effort in diagnostic-therapeutic pathway, to improve overall patient management and favoring an appropriate clinical approach. A raising number of diagnostic tests have been designed to elucidate the efficacy and/or safety of a specific drug or class of drugs for a targeted patient's group. Our paper reviewed the current understanding of the immunogenicity of biological drugs employed in the treatment of inflammatory diseases underlying the laboratory role.

Appropriate Therapeutic Drug Monitoring of Biologic Agents for Patients With Inflammatory Bowel Diseases.

BACKGROUND & AIMS: Therapeutic drug monitoring (TDM) is widely available for biologic therapies in patients with inflammatory bowel disease (IBD). We reviewed current data and provided expert opinion regarding the clinical utility of TDM for biologic therapies in IBD. METHODS: We used a modified Delphi method to establish consensus. A comprehensive literature review was performed regarding the use of TDM of biologic therapy in IBD and presented to international IBD specialists. Subsequently, 28 statements on the application of TDM in clinical practice were rated on a scale of 1 to 10 (1 = strongly disagree and 10 = strongly agree) by each of the panellists. Statements were accepted if 80% or more of the participants agreed with a score ≥7. The remaining statements were discussed and revised based on the available evidence followed by a second round of voting. RESULTS: The panel agreed on 24 (86%) statements. For anti-tumor necrosis factor (anti-TNF) therapies, proactive TDM was found to be appropriate after induction and at least once during maintenance therapy, but this was not the case for the other biologics. Reactive TDM was appropriate for all agents both for primary non-response and secondary loss of response. The panellists also agreed on several statements regarding TDM and appropriate drug and anti-drug antibody (ADA) concentration thresholds for biologics in specific clinical scenarios. CONCLUSION: Consensus was achieved towards the utility of TDM of biologics in IBD, particularly anti-TNF therapies. More data are needed especially on non-anti-TNF biologics to further define optimal drug concentration and ADA thresholds as these can vary depending on the therapeutic outcomes assessed.

Clinical relevance of monitoring serum adalimumab levels in axial spondyloarthritis.

Our aim was to assess the relationship between serum adalimumab levels, anti-drug antibodies (ADA) and disease activity in patients with axial spondylarthritis (SpA). We have carried out a single-centre cross-sectional study. adalimumab and ADA levels were analysed with ELISA and correlated with SpA activity using BASDAI and ASDAS scores. Adalimumab cut-off value was calculated to discriminate inactive disease/low disease activity (BASDAI < 4; ASDAS < 2.1) from moderate/high disease activity (BASDAI ≥ 4; ASDAS ≥ 2.1), using a receiver operating characteristic (ROC) curve. Up to January 2016, 51 consecutive patients were included. The median (range) age was 46.6 (18-68) and 47.1% were women. ADA prevalence was 27.5%, with none detected in the 21.6% receiving concomitant disease-modifying antirheumatic drugs (DMARDs) (p = 0.021). Adalimumab level was normal (> 3 mg/l) in 36 patients (70.6%), all without ADA. Fifteen patients (29.4%) had subtherapeutic adalimumab levels (< 3 mg/l), with ADA in 14 (93%). Median adalimumab (mg/l) was significantly higher in patients with inactive disease/low disease activity: BASDAI < 4 vs ≥ 4: 9.5 vs 2.6 (p < 0.01); ASDAS-CRP < 2.1 vs ≥ 2.1: 9.3 vs 0.3 (p < 0.001); ASDAS-ESR < 2.1 vs ≥ 2.1: 9.9 vs 3.0 (p < 0.001), and this finding was consistent with the result of the multivariate model. Patients with inactive disease/low disease activity presented significantly lower ADA levels. The adalimumab level cut-offs and area under the curve (AUC) obtained in the ROC curves were: ASDAS-CRP (< 2.1) 4.6 mg/l (AUC 81.2%; 95% CI 67.5-94.9; p < 0.001); ASDAS-ESR (< 2.1) 7.7 mg/l (AUC 82.4%; 95% CI 69.3-95.5; p < 0.001); BASDAI (< 4) 6.4 mg/l (AUC 73.5%; 95% CI 58.6-88.3; p < 0.01). In conclusion, presence of ADA in axial SpA patients treated with adalimumab was associated with lower serum drug levels. ADA levels were lower and adalimumab levels were higher in patients with inactive disease/low disease activity based on BASDAI and ASDAS indices. Concomitant treatment with MTX reduces de likelihood of finding ADA. Serum adalimumab levels above 4.6 mg/l are recommended to avoid compromising efficacy.

Novel Bispecific Antibody for Synovial-Specific Target Delivery of Anti-TNF Therapy in Rheumatoid Arthritis.

Biologic drugs, especially anti-TNF, are considered as the gold standard therapy in rheumatoid arthritis. However, non-uniform efficacy, incidence of infections, and high costs are major concerns. Novel tissue-specific agents may overcome the current limitations of systemic administration, providing improved potency, and safety. We developed a bispecific antibody (BsAb), combining human arthritic joint targeting, via the synovial-specific single-chain variable fragment (scFv)-A7 antibody, and TNFα neutralization, via the scFv-anti-TNFα of adalimumab, with the binding/blocking capacity comparable to adalimumab -immunoglobulin G (IgG). Tissue-targeting capacity of the BsAb was confirmed on the human arthritic synovium in vitro and in a synovium xenograft Severe combined immune deficient (SCID) mouse model. Peak graft accumulation occurred at 48 h after injection with sustained levels over adalimumab-IgG for 7 days and increased therapeutic effect, efficiently decreasing tissue cellularity, and markers of inflammation with higher potency compared to the standard treatment. This study provides the first description of a BsAb capable of drug delivery, specifically to the disease tissue, and a strong evidence of improved therapeutic effect on the human arthritic synovium, with applications to other existing biologics.

Pharmacokinetics, safety, and immunogenicity of HLX03, an adalimumab biosimilar, compared with reference biologic in healthy Chinese male volunteers: Results of a randomized, double-blind, parallel-controlled, phase 1 study.

The primary objective of this randomized, double-blind, parallel-controlled study (from December 2016 to October 2018) was to evaluate pharmacokinetic (PK) equivalence of adalimumab biosimilar HLX03 and reference adalimumab in healthy volunteers, and to assess safety, and immunogenicity of HLX03. The primary PK endpoints were maximum observed plasma concentration (Cmax ) and area under the concentration curve from time zero to the last quantifiable concentration (AUC0-t ). Equivalence was determined if the 90% confidence interval (CI) of geometric least square mean ratio between the two treatment groups were within the predefined range of 80%-125%. Safety and immunogenicity were monitored during the study. Healthy Chinese males (N = 220) were randomized 1:1 to receive a single subcutaneous 40 mg dose of HLX03 or China (CN)-sourced adalimumab. The ratios of the geometric mean of Cmax and AUC0-t were 102.2% and 105.7%, respectively, with corresponding 90% CIs falling in the predefined margins, which demonstrated PK equivalence between HLX03 and CN-adalimumab. The incidence of treatment-emergent adverse events (TEAEs) was similar in the two groups (73.8% and 66.0% in the HLX03 and CN-adalimumab groups, respectively). Grade 3-4 TEAEs were reported in 7.5% and 5.7% of participants, respectively. The incidences of participants with antidrug antibodies (HLX03: 96.2%; CN-adalimumab: 93.4%) or neutralizing antibodies (HLX03: 40.6%, CN-adalimumab: 41.4%) were comparable between groups. This study demonstrated PK bioequivalence between HLX03 and CN-adalimumab, with similar safety and immunogenicity profiles. These data support further clinical development of HLX03 as an adalimumab biosimilar.

Safety and tolerability of a humanized rabbit monoclonal antibody (SSS07) in healthy adults: Randomized double-blind placebo-controlled single ascending dose trial.

BACKGROUND/OBJECTIVE: SSS07, a humanized rabbit monoclonal antibody, can selectively block human tumor necrosis factor-α (TNF-α). The objective of this study was to assess the safety, tolerability, and relative immunogenicity of SSS07 after multiple single subcutaneous (SC) doses in healthy volunteers. METHODS: A total of 71 healthy volunteers were randomized to six sequential ascending-dose groups (5, 15, 30, 50, 75, and 100 mg), and except for the 100 mg group that only had one subject who received a placebo, all of the other groups included two placebo-control subjects. Safety, tolerability, and immunogenicity were assessed by physical examinations, vital signs, electrocardiography (ECG), clinical laboratory tests, and plasma anti-drug antibody (ADA) over 28 days for each group. Their concentrations of TNF-α were also analyzed. Only after safety and tolerance were determined in the lower-dose groups was the next dose group initiated. The dose increments did not exceed 100 mg. RESULTS: No serious adverse events or dose-limited toxicity (DLT) were observed, so 100 mg was defined as the maximum tolerated dose (MTD). Overall, 71 AEs and 59 treatment-related adverse events (TRAEs) were reported in 36 (60.0%) and 30 (50.0%) volunteers, respectively, who received SSS07. All AEs and TRAEs were mild or moderate and expected based on previous results with similar types of drugs, without new safety concerns. Except for infections and administration site reactions, the frequency and intensity of the other TRAEs were similar for SSS07 and placebo. No severe acute immune reactions occurred. The lower dose's immunogenicity was stronger than the higher doses. The highest ADA titer was observed 3 to 6 months after administration. CONCLUSION: SSS07 was generally safe and well tolerated in healthy Chinese volunteers. Higher immunogenicity was observed at low SSS07 concentration levels. The infections and administration site conditions might have been related to the immunogenicity and the degree of inhibition of TNF-α. However, the existence of ADA did not appear to affect the safety of the subjects throughout the follow-up period. These findings could support further investigations of treatments with humanized monoclonal antibodies.

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).

BACKGROUND: Anti-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. METHODS: Patients' 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. RESULTS: We 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). CONCLUSIONS: In 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.

Factors associated with reduced infliximab exposure in the treatment of pediatric autoimmune disorders: a cross-sectional prospective convenience sampling study.

BACKGROUND: Inadequate systemic exposure to infliximab (IFX) is associated with treatment failure. This work evaluated factors associated with reduced IFX exposure in children with autoimmune disorders requiring IFX therapy. METHODS: In this single-center cross-sectional prospective study IFX trough concentrations and anti-drug antibodies (ADAs) were measured in serum from children diagnosed with inflammatory bowel disease (IBD) (n = 73), juvenile idiopathic arthritis (JIA) (n = 16), or uveitis (n = 8) receiving maintenance IFX infusions at an outpatient infusion clinic in a tertiary academic pediatric hospital. IFX concentrations in combination with population pharmacokinetic modeling were used to estimate IFX clearance. Patient demographic and clinical data were collected by chart review and evaluated for their relationship with IFX clearance. RESULTS: IFX trough concentrations ranged from 0 to > 40 µg/mL and were 3-fold lower in children with IBD compared to children with JIA (p = 0.0002) or uveitis (p = 0.001). Children with IBD were found to receive lower IFX doses with longer dosing intervals, resulting in dose intensities (mg/kg/day) that were 2-fold lower compared to children with JIA (p = 0.0002) or uveitis (p = 0.02). Use of population pharmacokinetic analysis to normalize for variation in dosing practices demonstrated that increased IFX clearance was associated with ADA positivity (p = 0.004), male gender (p = 0.02), elevated erythrocyte sedimentation rate (ESR) (p = 0.02), elevated c-reactive protein (CRP) (p = 0.001), reduced serum albumin concentrations (p = 0.0005), and increased disease activity in JIA (p = 0.009) and IBD (p ≤ 0.08). No significant relationship between diagnosis and underlying differences in IFX clearance was observed. Multivariable analysis by covariate population pharmacokinetic modeling confirmed increased IFX clearance to be associated with anti-IFX antibody positivity, increased ESR, and reduced serum albumin concentrations. CONCLUSIONS: Enhanced IFX clearance is associated with immunogenicity and inflammatory burden across autoimmune disorders. Higher systemic IFX exposures observed in children with rheumatologic disorders are driven primarily by provider drug dose and interval selection, rather than differences in IFX pharmacokinetics across diagnoses. Despite maintenance IFX dosing at or above the standard recommended range for IBD (i.e., 5 mg/kg every 8 weeks), the dosing intensity used in the treatment of IBD is notably lower than dosing intensities used to treat JIA and uveitis, and may place some children with IBD at risk for suboptimal maintenance IFX exposures necessary for treatment 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.