Immunogenicity of TNF-Inhibitors

Long-term retention rates of anti-tumour necrosis factor and anti-interleukin-17 antibodies for patients with psoriatic arthritis

OBJECTIVE

While biologics have been used for the patients with psoriatic arthritis, there remains to be unknown concerning long-term retention rates. This study aims to present real-world data about long-term retention rates of biologics for the patients with psoriatic arthritis, and to undertake an analysis of the contributing factors.

METHODS

We examined retention rates and the reasons for discontinuation for biologics (adalimumab, certolizumab pegol, secukinumab, and ixekizumab) in 146 prescriptions (of which, 109 prescriptions were as naive) at our hospital since March 2010.

RESULTS

Throughout the entire course of the study, the 10-year retention rates were approximately 70% for adalimumab, 50% for ixekizumab, and 40% for secukinumab. When evaluating retention rates in the biologic-naïve subgroups, the 10-year retention rates were all approximately 70%. Regarding certolizumab pegol, the 3-year retention rate was approximately 75%. For adalimumab, a higher degree of arthritis at the initiation of treatment was found to correlate with an increased likelihood of secondary inefficacy. The main reason for discontinuation was secondary inefficacy, except for ixekizumab.

CONCLUSIONS

Each biologic exhibited a favourable long-term retention rate. The main reason for discontinuation was secondary inefficacy. Regarding adalimumab, secondary inefficacy was linked to the extent of arthritis upon treatment initiation.

Drug survival analysis of etanercept compared with monoclonal antibody tumour necrosis factor-α inhibitors in rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis: a propensity score-matched analysis from the Czech ATTRA registry

OBJECTIVES

To compare the drug survival of etanercept to monoclonal tumour necrosis factor-α inhibitors in rheumatoid arthritis, ankylosing spondylitis and psoriatic arthritis.

METHODS

Patients initiating first line biological therapy with tumour necrosis factor-α were propensity score matched and compared for drug survival with a Kaplan-Meier analysis.

RESULTS

We matched 657 to 657 patients in rheumatoid arthritis, the median survival time on etanercept was 44.6 months vs. 36.8 months on monoclonal antibody tumour necrosis factor-α inhibitors, with a hazard ratio of 0.94, p = 0.416 We matched 187 to 356 patients in ankylosing spondylitis, the median survival time on etanercept was 75.1 compared to 68.0 months, hazard ratio of 0.78, p = 0.087 We matched 81 to 160 psoriatic arthritis patients, the median survival time on etanercept was 35.8. compared to 65.7 months, hazard ratio 1.61, p = 0.011. Patients treated with etanercept had significantly worse psoriasis scoring during follow up.

CONCLUSIONS

We found comparable survival in rheumatoid arthritis and ankylosing spondylitis. In psoriatic arthritis, we found significantly shorter survival on etanercept, possibly due to worse response of skin and nail manifestations.

Evaluating the Performance of Two Automated Anti-drug Antibodies Assays for Infliximab and Adalimumab Without Acid Dissociation

Monitoring anti-drug antibodies (ADAs) to infliximab and adalimumab is critical to treatment management in various autoimmune disorders. The growing need for proactive therapeutic monitoring further requires the detection of ADAs in the presence of measurable concentrations of infliximab or adalimumab. To provide robust analytical assays for clinical application, we evaluated two automated immunoassays developed using ImmunoCAP™ technology and based on the bridging format to measure serum ADAs to infliximab and adalimumab respectively. Without an acid-dissociation step, these research prototype assays can detect a positive control monoclonal ADA towards infliximab and adalimumab, ranging from < 25 ng/ml to 10,000 ng/mL. Both assays exhibit imprecision less than 20% at different ADA titer levels and can distinguish ADAs towards different drug targets. In method comparison using authentic patient samples, the quantitative results of the ADA assays are not directly comparable to two existing clinical immunoassays for ADAs (correlation coefficient rs = 0.673 for infliximab ADAs; rs = 0.510 for adalimumab ADAs), presumably due to the lack of commutable ADA standards and the polyclonal nature of ADAs. Nevertheless, there is qualitative agreement between the methods when evaluating putative positive and negative patient samples (overall agreement 0.83 for infliximab ADAs; 0.76 for adalimumab ADAs). Biotin and high levels of rheumatoid factors may interfere with the performance of the automated assays due to competitive binding with the biotinylated drug and non-specific formation of bridging complexes. The two ImmunoCAP assays can provide new analytical methods for proactive therapeutic monitoring of adalimumab and infliximab.

Population Pharmacokinetics of Adalimumab in Juvenile Idiopathic Arthritis Patients: A Retrospective Cohort Study Using Clinical Care Data

BACKGROUND AND OBJECTIVE

Juvenile idiopathic arthritis (JIA) is a chronic autoimmune disorder that primarily affects the joints in children. Notably, it is known to co-occur with uveitis. Adalimumab, a monoclonal anti-TNF antibody, is effective in treating both conditions. A deeper understanding of the pharmacokinetics (PK) of adalimumab in JIA is crucial to advance in more personalized treatment approaches. The objective of this study is to evaluate the population PK profile of adalimumab in JIA and to explain causes for its variability.

MATERIALS AND METHODS

Adalimumab and antidrug antibody concentrations were retrospectively retrieved from the charts of patients with JIA. Initially, five literature-based population PK models of adalimumab were evaluated to assess their ability to describe the observed concentration-time profiles in the JIA cohort. These models included one specifically for the pediatric Crohn's disease population and four derived from studies in adult populations in healthy subjects and rheumatoid arthritis patients. Subsequently, a novel population PK model tailored to the JIA population was developed using NONMEM software. Monte Carlo simulations were then conducted utilizing the final PK model to visualize the concentration-time profile of adalimumab in patients with JIA and the impact of covariates.

RESULTS

A cohort of 50 patients with JIA with 78 available adalimumab samples was assessed. The mean age was 11.8 ± 3.9 years, with a median body weight of 49 kg (interquartile range 29.4-59.8 kg). All literature models adequately described the concentration-time profiles in JIA. The best model, which was developed in patients with rheumatoid arthritis during the maintenance phase of treatment, served as a basis for estimating clearance in JIA, resulting in a value of 0.37 L per day per 70 kg. Patient body weight, antidrug antibodies, methotrexate use, CRP level, and comorbidity of uveitis were found to have a significant impact on adalimumab clearance, and these reduced the inter-patient variability from 58.6 to 28.0%. On steady state in the simulated patient population, the mean trough level was 7.4 ± 5.5 mg/L. The two dosing regimens of 20 and 40 mg every other week, based on patients' body weight, resulted in comparable simulated overall drug exposure.

CONCLUSIONS

Five literature models effectively described adalimumab PK in this pediatric cohort, highlighting the potential for extrapolating existing models to the pediatric population. The new JIA model confirmed the effect of several known covariates and found a novel association for drug clearance with methotrexate use (lower) and uveitis (higher), which might have clinical relevance for personalized dosing in JIA.

Combination Therapy With Guselkumab and Golimumab in Patients With Moderately to Severely Active Ulcerative Colitis: Pharmacokinetics, Immunogenicity and Drug-Drug Interactions

A proof-of-concept study with the combination of guselkumab and golimumab in patients with ulcerative colitis (UC) has shown that the combination therapy resulted in greater efficacy than the individual monotherapies. The current analysis evaluated the pharmacokinetics (PK) and immunogenicity of guselkumab and golimumab in both the combination therapy and individual monotherapies. Blood samples were collected to evaluate serum concentrations and immunogenicity of guselkumab and golimumab. Population PK (PopPK) models were developed to assess the effects of combination therapy and other potential covariates on the PK of guselkumab and golimumab. The guselkumab PK was comparable between monotherapy and combination therapy, whereas golimumab concentrations were slightly higher with combination therapy. The anti-guselkumab antibody incidence was low with both monotherapy and combination therapy, and guselkumab immunogenicity did not impact the clearance. Conversely, the anti-golimumab antibody incidence with combination therapy was lower than that for monotherapy. PopPK analysis suggested that the slightly higher golimumab concentrations with combination therapy were partially due to lower immunogenicity and thus lower clearance with combination therapy. C-reactive protein (CRP) was also a significant covariate on golimumab clearance. The greater improvement of inflammation with combination therapy, as shown by reductions in CRP, may have also contributed to the higher golimumab concentrations. Combination therapy slightly decreased the clearance of golimumab, but not guselkumab clearance, in patients with UC. Lower immunogenicity and greater improvement of inflammation with combination therapy were potential mechanisms for slightly increased golimumab concentrations with combination therapy as compared with golimumab monotherapy.

Infliximab-Induced Improvement in Dercum's Disease

Dercum's disease (DD) is a rare and poorly understood disease characterized by obesity and painful lipomas throughout the body. Although the entity is well described in the literature, its etiology, prevalence, and treatment remain unclear. Currently, treatment is focused on pain management. We describe a case of a patient with DD who showed improvement with infliximab and methotrexate.

Meta-analysis: Persistence of advanced therapies in the treatment of inflammatory bowel disease

BACKGROUND

The expanding options in advanced therapies for ulcerative colitis (UC) and Crohn's disease (CD) present challenges in treatment selection. Persistence analysis assesses drug durability in real-world settings, acting as a surrogate marker for medication efficacy and tolerance. Unlike traditional comparative studies, persistence analysis provides insights extending beyond the initial year of treatment.

AIM

To provide real-world evidence on treatment effectiveness, tolerability and preferences of physicians and patients regarding various advanced therapies for IBD.

METHODS

We conducted a systematic review of observational studies up to March 2023 assessing advanced therapies' persistence in UC and CD. Advanced therapies under examination included infliximab, adalimumab, vedolizumab, ustekinumab, golimumab, certolizumab and tofacitinib. We pooled the persistence of each agent and conducted a meta-analysis to compare the persistence of newer agents with traditional TNF inhibitors (TNFi)-specifically infliximab and adalimumab.

RESULTS

Among 63 observational studies, vedolizumab had the highest 1-year persistence in UC (73.8%, 95% CI: 70.0%-77.6%) and ustekinumab in CD (77.5%, 95% CI: 72.9%-82.1%). Compared to TNFi, vedolizumab demonstrated increased persistence with a relative risk (RR) of 1.30 (95% CI: 1.19-1.41) for UC and 1.14 (95% CI: 1.09-1.20) for CD at 1 year, while ustekinumab demonstrated a RR of 1.15 (95% CI: 1.07-1.23) for CD at 1 year. Vedolizumab exhibited sustained increased persistence in UC over 2 years compared to TNFi (RR: 1.33, 95% CI 1.14-1.54).

CONCLUSION

This meta-analysis highlights the superior persistence of ustekinumab and vedolizumab over TNFi, and offers valuable insights for clinicians navigating the challenging landscape of UC and CD therapeutic choices.

Long-Term Follow-Up of Anti-Infliximab Antibodies in Patients With Radiographic Axial Spondyloarthritis: A Marker of Drug Survival and Tapering

OBJECTIVE

The aim of this study was to evaluate the influence of anti-infliximab (IFX) antibodies on three different points of care: response/tolerance to IFX, tapering strategy, and in a subsequent treatment with a second tumor necrosis factor inhibitor (TNFi).

METHODS

A prospective cohort of 60 patients with radiographic axial spondyloarthritis who received IFX were evaluated retrospectively regarding clinical/laboratorial data, IFX levels, and anti-IFX antibodies at baseline, after 6, 12 to 14, 22 to 24, 48 to 54, 96 to 102 weeks, and before tapering or switching.

RESULTS

Anti-IFX antibodies were detected in 27 patients (45%), of whom 23 (85.1%) became positive in the first year of IFX treatment. In comparison to the group that was negative for anti-IFX antibodies, patients who were positive for anti-IFX antibodies demonstrated the following: less use of methotrexate as a concomitant treatment to IFX (5 [18.5%] vs 14 [42.4%]; P = 0.048), more infusion reactions at 22 to 24 weeks (P = 0.020) and 48 to 54 weeks (P = 0.034), more treatment failures (P = 0.028) at 48 to 54 weeks, reduced overall IFX survival (P < 0.001), and lower sustained responses (P = 0.044). Of note, patients who were positive for anti-IFX antibodies exhibited a shorter tapering survival (9.9 months [95% confidence interval (CI) 4.0-15.8] vs 63.4 months [95% CI 27.9-98.8]; P = 0.004) in comparison with patients who were negative for anti-IFX antibodies. Conversely, for patients who failed IFX, patients who were positive for anti-IFX antibodies had better clinical response to the second TNFi at three months (15 [83.3%] vs 3 [27.3%]; P = 0.005) and six months (15 [83.3%] vs 4 [36.4%]; P = 0.017) than the patients who were negative for anti-IFX antibodies after switching.

CONCLUSION

This study provided novel data that anti-IFX antibodies is a parameter for reduced tapering survival, reinforcing its detection to guide clinical decision. Additionally, we confirmed in a long-term cohort the anti-IFX antibody association with worse IFX performance and as predictor of the second TNFi good clinical response.

Individual and population-level variability in HLA-DR associated immunogenicity risk of biologics used for the treatment of rheumatoid arthritis

Hypothesis

While conventional in silico immunogenicity risk assessments focus on measuring immunogenicity based on the potential of therapeutic proteins to be processed and presented by a global population-wide set of human leukocyte antigen (HLA) alleles to T cells, future refinements might adjust for HLA allele frequencies in different geographic regions or populations, as well for as individuals in those populations. Adjustment by HLA allele distribution may reveal risk patterns that are specific to population groups or individuals, which current methods that rely on global-population HLA prevalence may obscure.

Key findings

This analysis uses HLA frequency-weighted binding predictions to define immunogenicity risk for global and sub-global populations. A comparison of assessments tuned for North American/European versus Japanese/Asian populations suggests that the potential for anti-therapeutic responses (anti-therapeutic antibodies or ATA) for several commonly prescribed Rheumatoid Arthritis (RA) therapeutic biologics may differ, significantly, between the Caucasian and Japanese populations. This appears to align with reports of differing product-related immunogenicity that is observed in different populations.

Relevance to clinical practice

Further definition of population-level (regional) and individual patient-specific immunogenic risk profiles may enable prescription of the RA therapeutic with the highest probability of success to each patient, depending on their population of origin and/or their individual HLA background. Furthermore, HLA-specific immunogenicity outcomes data are limited, thus there is a need to expand HLA-association studies that examine the relationship between HLA haplotype and ATA in the clinic.

Real-World Effectiveness of Pegloticase Associated With Use of Concomitant Immunomodulatory Therapy

OBJECTIVE

The objective of this study was to ascertain pegloticase persistence and adverse events associated with concomitant immunomodulatory drug treatment in patients with gout.

METHODS

We conducted a retrospective analysis of patients with gout using the American College of Rheumatology's Rheumatology Informatics System for Effectiveness registry from January 2016 through June 2020. The first pegloticase infusion defined the index date. Based on concomitant immunomodulatory drug treatment, we identified three exposure groups: (1) immunomodulatory drug initiators (patients initiating an immunomodulatory prescription ±60 days from the index date), (2) prevalent immunomodulatory drug recipients (patients receiving their first immunomodulatory drug prescription >60 days before the index date with at least one prescription within ±60 days of the index date), and (3) immunomodulatory nonrecipients (patients receiving pegloticase without concomitant immunomodulatory drugs). We calculated the proportion of patients who achieved serum urate levels ≤6 mg/dL and who had laboratory abnormalities (white blood cell count <3.4 x 109/L, platelet count <135,000, hematocrit level <30%, alanine aminotransferase or aspartate aminotransferase level ≥1.5 times the upper limit normal value) within 180 days after the index date. Cox regression analyzed time to pegloticase discontinuation, controlling for potential confounders.

RESULTS

We identified 700 pegloticase recipients (91 immunomodulatory drug initiators, 33 prevalent immunomodulatory drug recipients, and 576 nonrecipients), with a median follow-up of 14 months. Immunomodulatory drug recipients were less likely to discontinue pegloticase. The adjusted hazard ratios of pegloticase discontinuation associated with concomitant immunomodulatory drug initiation and prevalent treatment were 0.52 (95% confidence interval [CI] 0.37-0.75) and 0.69 (95% CI 0.42-1.16), respectively. Laboratory abnormalities were uncommon (<5%) and were not higher in concomitant immunomodulatory drug treatment.

CONCLUSION

Consistent with clinical trials, results from this large observational registry suggest that concomitant immunomodulatory drug treatment improves pegloticase persistence.

Infliximab desensitization in patients with inflammatory bowel diseases: a safe therapeutic alternative

BACKGROUND

Hypersensitivity reactions (HSR) to the administration of infliximab (IFX) in Inflammatory Bowel Diseases (IBD) patients are not rare and usually lead to drug discontinuation. We report data on safety and effectiveness of desensitization to IFX in patients with previous HSR.

METHODS

We conducted a retrospective monocentric observational study. Patients for whom a desensitization protocol to IFX was realized after a previous HSR were included. Anti-drug antibodies (ADA) and IFX trough levels at both inclusion and six months after desensitization were collected. Clinical outcomes, including recurrence of HSR were evaluated.

RESULTS

From 2005 to 2020, 27 patients (Crohn's Disease: 26 (96%) were included). Desensitization after HSR was performed after a median time of 10.4 months (2.9-33.1). Nineteen (70%) patients received immunosuppressants at time of desensitization. Eight (30%) patients presented HSR at first (n = 2), second (n = 4) or third (n = 2) IFX perfusion after desensitization. None led to intensive care unit transfer or death. Thirteen (48%) had clinical response at 6 months and 8 (29%) were still under IFX treatment two years after desensitization. IFX trough levels and ADA were available for 14 patients at time of desensitization. Most patients (12 out of 14) had ADA at a high level. At 6 months, among the 7 patients with long term response to IFX, 4 presented a decrease of ADA titers and 2 had a significant trough level of IFX.

CONCLUSION

IFX desensitization in patients with IBD is a safe therapeutic alternative and represents a potential option for patients refractory to multiple biologics.What is already known? Hypersensitivity reactions to the administration of infliximab is frequent. Occurrence of hypersensitivity reaction, either immediate or delayed, usually leads to permanent drug discontinuation.What is new here? Infliximab desensitization is well tolerated with no hypersensitivity reaction recurrence in 70% of patients. Clinical success at 6 months was of 48% and around a third of patients remained under infliximab therapy two years after desensitization. Antidrug antibodies decreased and infliximab trough levels increased in these patients showing the impact of desensitization on immunogenicity.How can this study help patient care? Infliximab desensitization represents a potential option for patients refractory to multiple biologics who presented hypersensitivity reaction to the drug.

Safety, tolerability, and pharmacokinetics of single- and multiple-ascending doses of olamkicept: Results from randomized, placebo-controlled, first-in-human phase I trials

Olamkicept selectively inhibits the cytokine interleukin-6 (IL-6) trans-signaling pathway without blocking the classic pathway and is a promising immunoregulatory therapy for inflammatory bowel disease (IBD). These first-in-human, randomized, placebo-controlled, single- (SAD) and multiple-ascending dose (MAD) trials evaluated olamkicept safety, tolerability, pharmacokinetic, and pharmacodynamic characteristics. Doses tested in the SAD trial included seven single intravenous doses (0.75, 7.5, 75, 150, 300, 600, and 750 mg) and one subcutaneous (SC) dose (60 mg) given to healthy subjects (N = 64), and three intravenous doses (75 mg, 300 mg, and 750 mg) given to patients with Crohn's disease (CD; N = 24). Doses tested in the MAD trial included multiple intravenous doses (75, 300, and 600 mg once weekly for 4 weeks) given to healthy subjects (N = 24). No severe or serious treatment-emergent adverse events (TEAEs) were recorded. The most common TEAEs were headache, nasopharyngitis, and myalgia in the SAD trial, and diarrhea, headache, and cough in the MAD trial. Infusion-related reactions occurred in one and two subjects in the SAD and MAD trial, respectively, leading to treatment discontinuation in the MAD trial. Olamkicept showed dose-independent pharmacokinetics after single and multiple administrations, and there was no major difference in systemic exposure between healthy subjects and patients with CD. Complete target engagement (inhibition of phosphorylation of signal transducer and activator of transcription-3) was achieved in blood around or above olamkicept serum concentrations of 1-5 μg/mL. Overall, these results suggest that olamkicept is safe and well-tolerated in healthy subjects and patients with CD after single intravenous/SC and multiple intravenous administrations.

Evaluation of the Homogenous Mobility Shift Assay for Infliximab and Adalimumab Anti-drug Antibody Detection in the Clinical Laboratory

BACKGROUND

Detecting antidrug antibodies (ADAs) against infliximab or adalimumab is useful for therapeutic drug monitoring. Various ADA detection methods exist, and antibody titer is an output in some algorithms. Homogenous mobility shift assay (HMSA) measures relative ADA concentration and determines drug-ADA complex size in vitro. However, the relevance of complex size determination in drug monitoring remains unclear. Hence, the association between complex size, ADA concentration, and sample detectable neutralizing activity was evaluated.

METHODS

Sera from infliximab-treated and adalimumab-treated patients who tested positive for ADA in the National Screening Service were analyzed using 3 ADA assays. HMSA determined the relative ADA concentrations and complex sizes, competitive ligand-binding assay evaluated the sample neutralizing capacity, and enzyme-linked immunosorbent assay detected immunoglobulin (Ig)G4 ADA.

RESULTS

Most ADA-positive samples (>80%) formed drug-ADA dimer complexes, whereas 17% had dimer and multimer complexes, and 3% had multimeric complexes. Multimer presence had 100% positive predictive value for detectable neutralizing activity. ADA concentration and detectable neutralizing activity were moderately correlated (r = 0.65) in adalimumab-treated patients and strongly correlated (r = 0.81) in infliximab-treated patients. In adalimumab-treated patients, multimer presence was a stronger predictor of neutralizing activity than ADA concentration was, but not in infliximab-treated patients. However, in infliximab-treated patient samples, multimer presence revealed a distinct subset with high ADA concentrations, neutralizing activity, and IgG4 ADA.

CONCLUSIONS

Multimers detected using HMSA had a strong positive predictive value for competitive ligand-binding assay detectable neutralizing activity. Multimeric IgG4-containing ADA-drug complexes revealed a distinct subset of infliximab-treated patient samples, whose clinical relevance merits further investigation.

Formation and clearance of TNF-TNF inhibitor complexes during TNF inhibitor treatment

BACKGROUND AND PURPOSE

Millions of patients with inflammatory diseases are treated with tumour necrosis factor (TNF) inhibitors (TNFi). Individual treatment response varies, in part related to variable drug clearance. The role of TNF-TNFi complexes in clearance of the different TNFi is controversial. Moreover, mechanistic insight into the structural aspects and biological significance of TNF-TNFi complexes is lacking. We hypothesized a role for Fc-mediated clearance of TNF-TNFi immune complexes. Therefore, we investigated circulating TNF-TNFi complexes upon treatment with certolizumab-lacking Fc tails-in comparison with adalimumab, golimumab, infliximab and etanercept.

EXPERIMENTAL APPROACH

Drug-tolerant ELISAs were developed and used to quantify TNF during adalimumab, golimumab, etanercept, certolizumab and infliximab treatment in patients with inflammatory arthritis or ulcerative colitis for a maximum follow-up of 1 year. Effects on in vitro TNF production and Fc-mediated uptake of TNF-TNFi complexes were investigated for all five TNFi.

KEY RESULTS

Circulating TNF concentrations were >20-fold higher during certolizumab treatment compared with adalimumab, reaching up to 23.1 ng·ml-1 . Internalization of TNF-TNFi complexes by macrophages depended on Fc valency, with efficient uptake for the full antibody TNFi (three Fc tails), but little or no uptake for etanercept and certolizumab (one and zero Fc tail, respectively). TNF production was not affected by TNFi. Total TNF load did not affect clearance rate of total TNFi.

CONCLUSIONS AND IMPLICATIONS

Differences in TNFi structure profoundly affect clearance of TNF, while it is unlikely that TNF itself significantly contributes to target-mediated drug disposition of TNFi.

Clinical Pharmacology in Sarcoidosis: How to Use and Monitor Sarcoidosis Medications

When sarcoidosis needs treatment, pharmacotherapy is usually required. Although glucocorticoids work reliably and relatively quickly for sarcoidosis, these drugs are associated with numerous significant side effects. Such side effects are common in sarcoidosis patients, as the disease frequently has a chronic course and glucocorticoid treatment courses are often prolonged. For these reasons, corticosteroid-sparing and corticosteroid-replacing therapies are often required for sarcoidosis. Unfortunately, many healthcare providers who care for sarcoidosis patients are not familiar with the use of these agents. In this manuscript, we provide a review of the pharmacotherapy of sarcoidosis. We discuss the mechanism of action, dosing, side-effect profile, approach to monitoring and patient counselling concerning glucocorticoids, and the common alternative drugs recommended for use in the recent European Respiratory Society (Lausanne, Switzerland) Sarcoidosis Treatment Guidelines. We also discuss the use of these agents in special situations including hepatic insufficiency, renal insufficiency, pregnancy, breastfeeding, vaccination, and drug-drug interactions. It is hoped that this manuscript will provide valuable practical guidance to clinicians who care for sarcoidosis patients.

Adalimumab exhibits superiority over etanercept in terms of a numerically higher response rate and equivalent adverse events: A real-world finding

INTRODUCTION

Adalimumab (ADA) and etanercept (ETN) are the most commonly applied biologics for rheumatoid arthritis (RA) management in China; however, the evidence regarding their superiority is controversial. In addition, in real-world clinical settings, many factors may affect the application of these agents, such as dosage and administration period. Therefore, the present real-world study aimed to compare the efficacy and safety of ADA and ETN treatment in RA patients via the propensity score matching method.

METHODS

In total, 105 RA patients receiving ADA (n = 66) or ETN (n = 39) were reviewed in this retrospective study. The propensity score matching method was used to eliminate discrepancies in baseline features. Clinical response, low disease activity (LDA), and remission were evaluated based on the DAS28.

RESULTS

Before propensity score matching, compared with ETN, ADA yielded higher rates of clinical response at W24 (97.0% vs. 84.6%, p = .021), LDA at W12 (78.8% vs. 51.3%, p = .003), and remission at W24 (75.8% vs. 46.2%, p = .002). After propensity score matching, compared with ETN, ADA only achieved a higher rate of clinical response at W24 (96.3% vs. 77.8%, p = .043), whereas the rates of LDA and remission were not different between ADA and ETN treatments at any time point (all p > .05). In addition, the incidence of adverse events was not significantly different between the ADA and ETN treatments (all p > .05).

CONCLUSION

ADA shows superiority over ETN in terms of a numerically greater response rate and equivalent adverse events.

Analysis of ocular fluid in patients with ranibizumab-recalcitrant neovascular age-related macular degeneration who have serum anti-ranibizumab antibodies

PURPOSE

To evaluate whether anti-drug antibodies (ADAs) are present in the ocular fluid of patients with ranibizumab-recalcitrant neovascular age-related macular degeneration (nAMD).

METHODS

Two serum ADA-positive ranibizumab-recalcitrant patients and two serum ADA-negative controls were recruited from patients with nAMD treated with ranibizumab monotherapy. Recalcitrance was defined as persistent fluid after ≥6 monthly ranibizumab injections. Serum and aqueous humor ADAs were detected by enzyme-linked immunosorbent assay and immunoprecipitation, respectively.

RESULTS

Two of 156 ranibizumab-treated patients were ADA-positive. The patients received six and 14 ranibizumab injections, respectively, up to 4 weeks prior to blood collection. The serum ADA concentration was estimated to be approximately 50,000 ng/mL. Neutralizing ADAs were confirmed in both samples. A specific band was detected by immunoprecipitation only in ADA-positive samples, consistent with the results of enzyme-linked immunosorbent assay. Based on an assessment of the degree of sensitivity of commercially available anti-ranibizumab antibodies, it was estimated that the immunoprecipitation method could detect ADA levels >30 ng. Nevertheless, ADAs were not detected in the aqueous humor of either the experimental or control group.

CONCLUSION

In the aqueous humor, ADAs are either not present or are present at a lower concentration than that which can be detected by immunoprecipitation. This presumably reflects the fact that blood ADA is the product of systemic circulation clearance through anterior elimination of intravitreal ranibizumab. Based on our results, ADAs do not return to the eye in sufficient quantities to interfere with the action of ranibizumab in the vitreous cavity.

Development and validation of enzyme-linked immunosorbent assays for the measurement of infliximab and anti-drug antibody levels

Infliximab and its anti-drug antibody (ADA) serum concentrations exhibit a strong correlation with clinical response and loss of response. The use of therapeutic drug monitoring to measure the concentration of infliximab and ADA can facilitate clinical decision-making, helping patients attain optimal therapeutic effects. However, there are still limitations to the existing infliximab and its ADA detection methods. Therefore, this study aimed to develop and validate enzyme-linked immunosorbent assay (ELISA)-based methods for measuring infliximab and its ADA levels in human plasma according to the general recommendations for immunoassays. Free infliximab is bound by recombinant TNF-α and detected using HRP-labeled anti-human antibody. The ADA is captured by on-plate-coated infliximab and recognized by biotin-labeled infliximab. Two bridging ELISA assays were developed and after assay optimization and validation, these assays have been applied in ten patients with inflammatory bowel disease (IBD). In infliximab detection assay, a standard curve ranging from 0.10 μg/mL to 8.0 μg/mL with great precision and accuracy has been established. Drug tolerance of the ADA assay was that 100 ng/mL ADA could tolerate at least 5.0 μg/mL infliximab in the plasma using a commercially available monoclonal anti-infliximab antibody as the positive control. The ADA screening and confirmatory assays achieved a sensitivity of 36.74 ng/mL and 37.15 ng/mL, respectively. All other assay characteristics met the requirements. The mean concentration of infliximab in eight patients with IBD was 7.88 (1.87-21.1) μg/mL, and the ADA levels were all negative. Moreover, the concentrations of infliximab in the remaining two patients were below the LLOQ and the ADAs were positive. Thus, accurate and sensitive ELISA methods have been developed and validated for the detection of infliximab and its ADA concentrations and have been successfully applied to clinical therapeutic drug monitoring.

Interplay between inflammatory bowel disease therapeutics and the gut microbiome reveals opportunities for novel treatment approaches

Inflammatory bowel disease (IBD) is a complex heterogeneous disorder defined by recurring chronic inflammation of the gastrointestinal tract, attributed to a combination of factors including genetic susceptibility, altered immune response, a shift in microbial composition/microbial insults (infection/exposure), and environmental influences. Therapeutics generally used to treat IBD mainly focus on the immune response and include non-specific anti-inflammatory and immunosuppressive therapeutics and targeted therapeutics aimed at specific components of the immune system. Other therapies include exclusive enteral nutrition and emerging stem cell therapies. However, in recent years, scientists have begun to examine the interplay between these therapeutics and the gut microbiome, and we present this information here. Many of these therapeutics are associated with alterations to gut microbiome composition and functionality, often driving it toward a "healthier profile" and preclinical studies have revealed that such alterations can play an important role in therapeutic efficacy. The gut microbiome can also improve or hinder IBD therapeutic efficacy or generate undesirable metabolites. For certain IBD therapeutics, the microbiome composition, particularly before treatment, may serve as a biomarker of therapeutic efficacy. Utilising this information and manipulating the interactions between the gut microbiome and IBD therapeutics may enhance treatment outcomes in the future and bring about new opportunities for personalised, precision medicine.

Treatment overview of axial spondyloarthritis in 2023

The treatment of patients with axial spondyloarthritis (axSpA) is characterized by non-pharmacological and pharmacological treatment options. It may depend on the type and extent of musculoskeletal and extramusculoskeletal manifestations. Recent data on non-pharmacological treatment options, such as physical activity, physiotherapy, and modification of lifestyle factors, are summarized in this review. Moreover, we have provided an overview on non-steroidal anti-inflammatory drugs and the ever-expanding number of biological and targeted synthetic disease-modifying antirheumatic drugs (bDMARDs and tsDMARDs, respectively). In addition to data on efficacy and safety, the review also encompasses data on switching/cycling, tapering, and treatment selection for specific patient subgroups to optimize treatment outcomes.

Real-world Comparative Effectiveness of Methotrexate-based Combinations for Rheumatoid Arthritis: A Retrospective Cohort Study

PURPOSE

Guidelines recommend using disease-modifying antirheumatic drugs (DMARDs) in combination with methotrexate (MTX) for patients with rheumatoid arthritis (RA) after monotherapy. Little is known about the real-world comparative effectiveness of these MTX-DMARD combinations. This study compared the effectiveness of various MTX-based DMARD combinations for patients with RA initiating MTX-DMARD combination therapy using administrative claims database.

METHODS

This retrospective cohort study included adults (aged ≥18 years) with RA who initiated MTX combination treatment with conventional synthetic DMARDs (csDMARDs), tumor necrosis factor inhibitor (TNFi) biologic DMARDs (bDMARDs), non-TNFi bDMARDs, or targeted synthetic DMARDs (tsDMARDs) between July 1, 2012, and December 31, 2013 (index date), from the MarketScan Commercial Claims Data. Patients had continuous enrollment from the 6 months of preindex period until the 12 months of postindex period. The MTX-based DMARD combination therapy cohort was defined as ≥1 MTX prescription in the first 30 days from the index date and ≥14 days overlapping use of the prescription fills of the MTX and the index DMARD. Effectiveness was measured by using the claims algorithm (dosing, switching, addition, oral glucocorticoid use, or multiple glucocorticoid injection). Propensity score analysis with the inverse probability of treatment weighting (PS-IPTW), estimated by using the generalized boosted machine learning method, was used to balance the distribution of baseline variables between the combination groups. Multivariable logistic regression using PS-IPTW was conducted to compare the effectiveness of the combination groups. Sensitivity analysis evaluated the modified effectiveness algorithms or the time to the first treatment failure.

FINDINGS

A total of 3174 adult patients with RA starting an MTX-DMARD combination therapy were identified (mean [SD] age, 50 [9] years), including 1568 (49%) initiating a csDMARD + MTX, 1343 (42%) initiating TNFi + MTX, and 240 (8%) initiating non-TNFi bDMARD + MTX, and 23 (1%) initiating tsDMARD + MTX. Owing to the small sample, the tsDMARD combination group was not included in the comparative analysis. Algorithm-based therapy effectiveness was found in 9.95% of the csDMARD + MTX, 20.48% of the TNFi + MTX, and 20.83% of the non-TNFi + MTX groups. PS-IPTW showed that the csDMARD combination is less effective (adjusted odds ratio, 0.422; 95% CI, 0.341-0.524) than the TNFi combination; however, the non-TNFi biologic combination had similar effectiveness (aOR, 1.063; 95% CI, 0.680-1.662) compared to the TNFi combination. Sensitivity analyses confirmed the main results.

IMPLICATIONS

Among RA patients initiating MTX-DMARD combinations, both non-TNFi biologics and TNFi-based combinations with MTX were equally effective, but csDMARD + MTX was less effective than the TNFi plus MTX.

TNFα rs1800629 Polymorphism and Response to Anti-TNFα Treatment in Behçet Syndrome: Data from an Italian Cohort Study

Tumor Necrosis Factor-alpha (TNFα) rs1800629 (-308G>A) is a single nucleotide polymorphism (SNP) related to variable responses to anti-TNFα therapy. This therapy is efficient in severe and refractory manifestation of Behçet syndrome (BS), an auto-inflammatory systemic vasculitis. We investigated (1) the association between rs1800629 genotypes and responses to therapy and (2) the correlation between SNP and clinical patterns in a cohort of 74 BS Italian patients receiving anti-TNFα therapy with a follow-up of at least 12 months. The rs1800629 was genotyped through amplification, direct sequencing and bioinformatics analyses. The rs1800629 GG and GA genotypes were assessed as predictors of outcomes dividing the patients between therapy responders and non-responders. The rs1800629 GG and GA genotypes were found, respectively, in 59/74 (79.7%) and 15/74 BS patients (21.3%) (p < 0.05). We identified 16/74 (21.9%) non-responder patients, of which 9/16 (56.3%) showed the GG genotype and 7/16 (43.7%) the GA genotype. A total of 50/58 (86.2%) responder patients showed the GG genotype, and 8/58 (13.8%) the GA genotype (p < 0.05). The percentage of non-responder females (68.8%) was significantly higher than non-responder males (31.2%) (p < 0.05). No correlation between SNP and clinical patterns was observed. To successfully include rs1800629 as a predictive biomarker of TNFα inhibitor response, genome-wide association studies in larger, well-characterised cohorts are required.

Surface plasmon resonance assays for the therapeutic drug monitoring of infliximab indicate clinical relevance of anti-infliximab antibody binding properties

OBJECTIVES

The therapeutic antibody infliximab (IFX) has improved the life quality of numerous autoinflammatory disease patients. However, IFX can trigger the generation of anti-drug antibodies (ADA), whose optimal evaluation and management are currently subject of controversial discussions. We present two novel surface plasmon resonance (SPR) biosensor assays for therapeutic drug monitoring of IFX and characterization of ADA and investigated the diagnostic value of ADA binding properties.

METHODS

IFX and ADA were quantified via developed SPR biosensor assays (IFXmon and ADAmon, respectively) and diagnostics-approved ELISA in sera from inflammatory bowel disease patients. Pre-analytic ADA enrichment with magnetic beads enabled analytical drug tolerance of the ADAmon assay. The dissociation ratio (DissR) as an index for ADA:IFX binding stability was calculated from the SPR sensorgrams of ADA quantification runs.

RESULTS

IFX levels determined by IFXmon assay and ELISA showed high agreement, whereas ADA quantification concordance between ADAmon assay and ELISA was poor. In patients, DissR was predominantly constant over time and differed significantly between therapy outcomes. A DissR cut-off of 1.524 indicated undetectable IFX levels with 71.4% sensitivity and 88.9% specificity. Additionally, the SPR reference surface was exploited as serum-individual negative control to check result plausibility within multi-sample run sequences.

CONCLUSIONS

Overall, both SPR biosensor assays exhibited reliable quantitative performance with accuracies superior to their ELISA counterparts and precision inferior to ELISA only for ADAmon. DissR presented itself as promising ADA binding parameter and could contribute to both earlier and more tailored therapeutic decisions.

Comparative Evaluation of Four Commercially Available Immunoassays for Therapeutic Drug Monitoring of Infliximab and Adalimumab

Therapeutic drug monitoring (TDM) of anti-TNF-α is an important tool in clinical practice for inflammatory diseases. In this study, we have evaluated the performance of several assays for drug and antidrug antibodies (ADA) measurement in the serum. 50 sera from patients treated with infliximab (IFX) and 49 sera from patients treated with adalimumab (ADAL) were monitored with four immunoassays. We have compared Promonitor, i-Track10^®, and ez-track1 assays to our gold standard Lisa Tracker^® ELISA using Cohen's kappa, Passing-Bablok, and Bland-Altman analysis. The qualitative analysis evaluated by Cohen's kappa values found for IFX measurements an "almost perfect" concordance for Promonitor, "moderate" for i-Track10^® and "substantial" for ez-Track1. For ADAL, kappa values were "moderate" for all tested methods. For anti-IFX, kappa values were "almost perfect" for Promonitor, "fair" for i-Track10^®, and "substantial" for ez-Track1. For anti-ADAL, kappa values were "almost perfect" for all three assays. For quantitative analysis of drug measurements, Pearson's r values were all above 0.9 and Lin's concordance coefficients of all immunoassays were around 0.80. Performances of the four evaluated immunoassays were acceptable for TDM based on our laboratory experience. Nevertheless, concordance between the four methods for IFX measurement was not perfect and we recommend the use of the same assay for the follow-up of a given patient. The performances of the four immunoassays evaluated were similar and are acceptable for TDM based on our laboratory experience.

Case Report: Patient with deficiency of ADA2 presenting leukocytoclastic vasculitis and pericarditis during infliximab treatment

Deficiency of adenosine deaminase 2 (DADA2), first reported in 2014, is a disease with great phenotypic variability, which has been increasingly reported. Therapeutic response depends on the phenotype. We present a case of an adolescent with recurrent fever, oral aphthous ulcers, and lymphadenopathy from 8 to 12 years of age and subsequently presented with symptomatic neutropenia. After the diagnosis of DADA2, therapy with infliximab was started, but after the second dose, she developed leukocytoclastic vasculitis and showed symptoms of myopericarditis. Infliximab was switched to etanercept, with no relapses. Despite the safety of tumor necrosis factor alpha inhibitors (TNFi), paradoxical adverse effects have been increasingly reported. The differential diagnosis between disease new-onset manifestations of DADA2 and side effects of TNFi can be challenging and warrants further clarification.

Drug Survival of Tumor Necrosis Factor-Alpha Inhibitors and Switched Subsequent Biologic Agents in Patients with Psoriasis: A Retrospective Study

INTRODUCTION

This study aimed to retrospectively examine the drug survival of tumor necrosis factor (TNF)-alpha inhibitors and switched subsequent biologic agents after discontinuation of TNF inhibitors.

METHODS

This real-world setting study was conducted at a single academic center. We included patients who were treated with adalimumab (n = 111), certolizumab pegol (n = 12), and infliximab (n = 74) at Jichi Medical University Hospital from 1 January 2010 to 31 July 2021.

RESULTS

No significant differences were noted in drug survival between the three TNF inhibitors. The 10-year drug survival rate for adalimumab and infliximab was 14% and 18%, respectively. Of the patients who discontinued TNF inhibitors for any reason (n = 137), 105 chose biologics as their subsequent treatment. The subsequent biologics included 31 cases of TNF inhibitors (adalimumab in 20, certolizumab pegol in 1, and infliximab in 10), 19 of interleukin-12/23 inhibitor (ustekinumab), 42 of interleukin-17 inhibitors (secukinumab in 19, brodalumab in 9, and ixekizumab in 14) and 13 of interleukin-23 inhibitors (guselkumab in 11, risankizumab in 1, and tildrakizumab in 1). Cox proportional hazards analysis for the subsequent drugs in cases of discontinuation due to inadequate efficacy revealed that female sex was a predictor of drug discontinuation (hazard ratio 2.58, 95% confidence interval 1.17-5.70) and that taking interleukin-17 inhibitors rather than TNF inhibitors was a predictor of drug persistence (hazard ratio 0.37, 95% confidence interval 0.15-0.93).

CONCLUSIONS

Interleukin-17 inhibitors may be a favorable option for patients who need to switch from TNF inhibitors due to inadequate efficacy. However, this study is limited by the small number of cases and its retrospective design.

Free antibodies-to-infliximab are biomarker for predicting the effect of dose intensification in pediatric Crohn's disease patients with secondary loss of response

Background

Immunogenicity to antitumor necrosis factor alpha agents, such as infliximab (IFX), may lead to therapeutic failure.

Objectives

This study evaluated the relationship between free and total antibodies-to-infliximab (ATIs), trough levels (TLs) of IFX, and the response to dose intensification.

Design

We performed a prospective, observational study including pediatric patients with Crohn's disease (CD) receiving IFX maintenance therapy without dose intensification.

Methods

We compared clinical and laboratory outcomes according to the presence of free and total ATIs. Factors associated with response to IFX dose intensification were investigated by analyzing IFX TLs and free and total ATIs.

Results

Of the 98 patients, 9 patients had detectable free ATIs and 38 patients had total ATIs. Patients with free ATIs had significantly lower TLs (0.7 versus 5.1 µg/mL, p < 0.001) than patients without free ATIs. However, there was no difference in the IFX TLs according to the presence of total ATIs (p = 0.2523). Analysis of the 38 samples with total ATIs showed that response to dose intensification was significantly lower in patients with free ATIs than those without free ATIs (22.2% versus 65.5%, p < 0.001). In addition, free ATIs were the only factor with poor response to dose intensification [odds ratio (OR): 14.15, 95% confidence interval (CI): 1.31-151.97, p = 0.0140]. According to the receiver operating characteristic analysis, the optimal cutoff level indicating non-response to IFX dose intensification was 30.0 AU/mL for free ATIs concentration (area under curve, 0.792; 95% CI: 0.590-0.942; sensitivity, 60.0%; specificity, 96.7%; p = 0.0241).

Conclusion

Free ATIs, but not total ATIs, have a negative impact on the course of CD. Free ATIs are potential reliable biomarker for predicting the effect of dose intensification in patients with loss of response to IFX. Future studies based on serial and proactive therapeutic drug monitoring are required in the future.

Anti-Drug Antibodies in the Biological Therapy of Autoimmune Rheumatic Diseases

Autoimmune rheumatic diseases are a cluster of heterogeneous disorders that share some clinical symptoms such as pain, tissue damage, immune deregulation, and the presence of inflammatory mediators. Biologic disease-modifying antirheumatic drugs are some of the most effective treatments for rheumatic diseases. However, their molecular and pharmacological complexity makes them potentially immunogenic and capable of inducing the development of anti-drug antibodies. TNF inhibitors appear to be the main contributors to immunogenicity because they are widely used, especially in rheumatoid arthritis. Immunogenicity response on these treatments is crucial since the appearance of ADAs has consequences in terms of safety and efficacy. Therefore, this review proposes an overview of the immunogenicity of biological agents used in autoimmune rheumatic diseases highlighting the prevalence of anti-drug antibodies.

Impact of Stress on the Immunogenic Potential of Adalimumab

Monoclonal antibodies against tumor necrosis factor-alpha (TNFα) are widely used for treatment of inflammatory diseases. However, despite the inhibitory effect this class of drugs has on the immune system, anti-drug antibodies are often formed with continuous use. Particles formed during stress conditions, which can be used to simulate storage and handling conditions of commercial antibodies, have previously been associated with the formation of anti-drug antibodies. This study investigates the relationship between particles, oligomerization, folding and chemical degradation on the in vitro cytokine response toward the TNFα inhibitor adalimumab. Adalimumab aggregates generated using stir and heat stress were fractionated into distinct sub-populations, and their structure and immunogenic potential were evaluated. A chemically degraded sample of adalimumab was included to compare particle composition with the milder accelerated heat and stir stressed conditions. Particles from stressed adalimumab samples induced elevated cytokine levels and CD4+ T cell proliferation in vitro compared to non-stressed samples. Samples enriched with both submicron and subvisible particles of adalimumab induced the strongest cytokine release and the strongest CD4+ T cell proliferation despite maintaining some TNFα inhibitory functionality. Samples that were stressed and subsequently purified of subvisible and submicron particles did not elicit a significantly higher cytokine response or show increased CD4+ T cell proliferation compared to a non-stressed sample. Oxidation-induced chemical modifications in adalimumab, mainly in Met, His, Trp, and Tyr, were not found to be sufficient in absence of particle formation to induce increased CD4+ T cell proliferation or cytokine release despite less decreased TNFα inhibitory activity of adalimumab. These observations provide further evidence that particles do indeed potentiate the immunogenic potential of adalimumab.

Subcutaneous Infliximab Monotherapy Versus Combination Therapy with Immunosuppressants in Inflammatory Bowel Disease: A Post Hoc Analysis of a Randomised Clinical Trial

BACKGROUND AND OBJECTIVE

Whether benefits and risks of intravenous (IV) infliximab combotherapy with immunosuppressants versus infliximab monotherapy apply to subcutaneous (SC) infliximab is unknown. This post hoc analysis of a pivotal randomised CT-P13 SC 1.6 trial aimed to compare SC infliximab monotherapy with combotherapy in inflammatory bowel disease (IBD).

METHODS

Biologic-naïve patients with active Crohn's disease or ulcerative colitis received CT-P13 IV 5 mg/kg at Week (W) 0 and 2 (dose-loading phase). At W6, patients were randomised (1:1) to receive CT-P13 SC 120 or 240 mg (patients < 80 or ≥ 80 kg) every 2 weeks until W54 (maintenance phase), or to continue CT-P13 IV every 8 weeks until switching to CT-P13 SC from W30. The primary endpoint-non-inferiority of trough serum concentrations-was assessed at W22. We report a post hoc analysis comparing pharmacokinetic, efficacy, safety and immunogenicity outcomes up to W54 for patients randomised to CT-P13 SC, stratified by concomitant immunosuppressant use.

RESULTS

Sixty-six patients were randomised to CT-P13 SC (37 monotherapy, 29 combotherapy). At W54, there were no significant differences in the proportions of patients achieving target exposure (5 µg/mL; 96.6% monotherapy vs 95.8% combotherapy; p > 0.999) or meeting efficacy or biomarker outcomes including clinical remission (62.9% vs 74.1%; p = 0.418). Monotherapy and combotherapy groups had comparable immunogenicity (anti-drug antibodies [ADAs]: 65.5% vs 48.0% [p = 0.271], neutralising antibodies [in ADA-positive patients]: 10.5% vs 16.7% [p = 0.630], respectively).

CONCLUSIONS

Pharmacokinetics, efficacy and immunogenicity were potentially comparable between SC infliximab monotherapy and combotherapy in biologic-naïve IBD patients.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02883452.

Efficacy and Safety of CMAB008 Compared with Innovator Infliximab in Patients with Moderate-to-Severe Rheumatoid Arthritis Receiving Concomitant Methotrexate: A Randomized, Double-blind, Multi-center, Phase III Non-inferiority Study

OBJECTIVES

The aim of this work is to verify the non-inferior efficacy and safety of CMAB008 compared with innovator infliximab in rheumatoid arthritis patients combined with methotrexate.

METHODS

We conducted a randomized, double-blinded, parallel, positive control design, multicenter study, with a stable dose of methotrexate. Patients were enrolled randomly with a ratio of 1:1 to receive intravenously CMAB008 3 mg/kg or innovator infliximab 3 mg/kg at weeks 0, 2, 6, 14, 22 and 30. The primary efficacy endpoint was American College of Rheumatology 20% improvement criteria (ACR20) response rate at week 30. The non-inferiority was established if the lower limit of the one-sided 97.5% confidence interval (CI) for the difference was more than - 15% and the equivalence was established if the two-sided 95% CI was within ± 15% in an exploratory equivalence analysis. The secondary endpoints included other efficacy assessment parameters, as well as immunogenicity, safety, and pharmacokinetics.

RESULTS

In the full analysis population (FAS), 110 (57.6%) of 191 patients in the CMAB008 group and 120 (62.2%) of 193 patients in the innovator infliximab group reached the primary outcome of ACR20 at week 30. The differences of the rates were - 4.6% and the lower limit of one-sided 97.5% confidence interval was - 14.29%, not less than the lower limit of the non-inferiority margin (- 15%); so CMAB008 was non-inferior to innovator infliximab. Further, CMAB008 was equivalent to innovator infliximab both in FAS (difference - 4.6%, 95% CI - 14.29% to 5.12%) and PPS (difference - 3.3%, 95% CI - 13.18% to 6.62%). The efficacy, safety, immunogenicity, and pharmacokinetics are highly similar between CMAB008 and innovator infliximab.

CONCLUSIONS

Non-inferior efficacy of CMAB008 to innovator infliximab is illustrated with similar early and lasting therapeutic effects, and the equivalence is further demonstrated. CMAB008 is well tolerated and has semblable safety compared with the innovator infliximab.

TRIAL REGISTRATION NUMBER

NCT03478111.

Non-anti TNFα biologic agents for non-infectious uveitis associated with systemic inflammatory diseases: a systematic review

INTRODUCTION

Non-infectious uveitis related to systemic inflammatory diseases represents a leading cause of blindness. Anti-TNFα agents are the first-line biologic therapy after traditional immunosuppressants, both for the control of ocular and systemic involvement. However, a subgroup of patients fails anti-TNFα agents, due to primary inefficacy, loss of efficacy or adverse events.

AREAS COVERED

This systematic review summarizes current evidence on the efficacy and safety of non-anti-TNFα biologics in adult patients with non-infectious uveitis associated with systemic inflammatory diseases. The systematic review of PubMed and Embase yielded 3663 records, from which 16 studies were included (13 non-controlled, 3 controlled trials). Most studies focused on Behçet's syndrome (BS) and juvenile idiopathic arthritis (JIA) and assessed the efficacy of tocilizumab (n=11), rituximab (n=3), secukinumab (n=1), or anakinra/canakinumab (n=1). A body of evidence supports the use of tocilizumab BS and JIA-associated uveitis, for improving visual acuity, reducing central macular thickness, inducing ocular remission, and sparing corticosteroids. Preliminary data suggest that rituximab may represent a valid alternative, particularly in JIA, while anakinra/canakinumab might play a role in BS-associated uveitis. Conversely, the role of secukinumab appears limited.

EXPERT OPINION

Current evidence encourages further investigations on the efficacy and safety of non-anti-TNFα agents in non-infectious non-idiopathic uveitis.

Perspectives of Therapeutic Drug Monitoring of Biological Agents in Non-Infectious Uveitis Treatment: A Review

Biological drugs, especially those targeting anti-tumour necrosis factor α (TNFα) molecule, have revolutionized the treatment of patients with non-infectious uveitis (NIU), a sight-threatening condition characterized by ocular inflammation that can lead to severe vision threatening and blindness. Adalimumab (ADA) and infliximab (IFX), the most widely used anti-TNFα drugs, have led to greater clinical benefits, but a significant fraction of patients with NIU do not respond to these drugs. The therapeutic outcome is closely related to systemic drug levels, which are influenced by several factors such as immunogenicity, concomitant treatment with immunomodulators, and genetic factors. Therapeutic drug monitoring (TDM) of drug and anti-drug antibody (ADAbs) levels is emerging as a resource to optimise biologic therapy by personalising treatment to bring and maintain drug concentration within the therapeutic range, especially in those patients where a clinical response is less than expected. Furthermore, some studies have described different genetic polymorphisms that may act as predictors of response to treatment with anti-TNFα agents in immune-mediated diseases and could be useful in personalising biologic treatment selection. This review is a compilation of the published evidence in NIU and in other immune-mediated diseases that support the usefulness of TDM and pharmacogenetics as a tool to guide clinicians’ treatment decisions leading to better clinical outcomes. In addition, findings from preclinical and clinical studies, assessing the safety and efficacy of intravitreal administration of anti-TNFα agents in NIU are discussed.

Past, Present and (Foreseeable) Future of Biological Anti-TNF Alpha Therapy

Due to the key role of tumor necrosis factor-alpha (TNF-α) in the pathogenesis of immunoinflammatory diseases, TNF-α inhibitors have been successfully developed and used in the clinical treatment of autoimmune disorders. Currently, five anti-TNF-α drugs have been approved: infliximab, adalimumab, golimumab, certolizumab pegol and etanercept. Anti-TNF-α biosimilars are also available for clinical use. Here, we will review the historical development as well as the present and potential future applications of anti-TNF-α therapies, which have led to major improvements for patients with several autoimmune diseases, such as rheumatoid arthritis (RA), ankylosing spondylitis (AS), Crohn's disease (CD), ulcerative colitis (UC), psoriasis (PS) and chronic endogenous uveitis. Other therapeutic areas are under evaluation, including viral infections, e.g., COVID-19, as well as chronic neuropsychiatric disorders and certain forms of cancer. The search for biomarkers able to predict responsiveness to anti-TNF-α drugs is also discussed.

Antidrug Antibodies to Tumor Necrosis Factor α Inhibitors in Patients With Noninfectious Uveitis

Importance

Tumor necrosis factor inhibitors (TNFis) can induce antidrug antibody (ADA) formation and loss of therapeutic response. However, the utility of ADA testing and the association between ADAs and treatment response in patients with noninfectious uveitis (NIU) is not well understood.

Objective

To assess the frequency of ADAs and their association with drug levels and clinical response in patients with NIU treated with adalimumab or infliximab.

Design, Setting, and Participants

This retrospective cross-sectional study included patients diagnosed with NIU who received adalimumab or infliximab and underwent testing for serum drug level and ADAs at the National Eye Institute from September 2017 to July 2021.

Exposures

Serum drug level testing with reflex testing for ADA levels was performed.

Main Outcomes and Measures

The main outcome was the association between drug levels and ADAs, clinical response, and concurrent antimetabolite use in patients treated with TNFis for NIU.

Results

Of 54 patients included in the study, 42 received adalimumab (mean [SD] age, 43.6 [19.6] years; 25 [59.5%] female) and 12 received infliximab (mean [SD] age, 42.7 [20.4] years; 7 [58.3%] male). In the adalimumab group, mean (SD) drug level was 9.72 (6.82) μg/mL, mean (SD) ADA level was 84.2 (172.9) arbitrary units/mL, and ADA frequency was 35.7% (15 of 42 patients). Mean drug level was lower in those with ADAs compared with those without ADAs (mean [SD], 2.8 [2.6] μg/mL vs 13.6 [5.2] μg/mL; difference: 10.8 μg/mL; 95% CI, 8.3-13.2 μg/mL; P < .001). There was a higher mean drug level with concurrent antimetabolite use compared with monotherapy (mean [SD], 11.0 [7.3] μg/mL vs 6.8 [4.5] μg/mL; difference: -4.2 μg/mL; 95% CI, -8.7 to 0.2 μg/mL; P = .06). Multivariable modeling showed that a 1-arbitrary unit increase in ADAs was associated with a -0.02 μg/mL (95% CI, -0.01 to -0.34 μg/mL) difference in mean drug level (P < .001). Favorable clinical response was associated with a threshold drug level above 2.7 μg/mL or an antibody level below 15.2 μg/mL. The mean (SD) drug level in the infliximab group was 27.02 (18.15) μg/mL, and no ADAs were detected.

Conclusions and Relevance

In this study, 35.7% of adalimumab-treated patients with NIU had ADAs. The presence of ADAs was associated with lower drug levels, and higher ADA levels were associated with increased risk of TNFi treatment failure. Although limited by the retrospective design, our results suggest that therapeutic drug monitoring may be considered among patients experiencing therapy failure to help exclude ADAs as a potential cause of treatment failure.

A bioengineered probiotic for the oral delivery of a peptide Kv1.3 channel blocker to treat rheumatoid arthritis

Engineered microbes for the delivery of biologics are a promising avenue for the treatment of various conditions such as chronic inflammatory disorders and metabolic disease. In this study, we developed a genetically engineered probiotic delivery system that delivers a peptide to the intestinal tract with high efficacy. We constructed an inducible system in the probiotic Lactobacillus reuteri to secrete the Kv1.3 potassium blocker ShK-235 (LrS235). We show that LrS235 culture supernatants block Kv1.3 currents and preferentially inhibit human T effector memory (T_EM) lymphocyte proliferation in vitro. A single oral gavage of healthy rats with LrS235 resulted in sufficient functional ShK-235 in the circulation to reduce inflammation in a delayed-type hypersensitivity model of atopic dermatitis mediated by T_EM cells. Furthermore, the daily oral gavage of LrS235 dramatically reduced clinical signs of disease and joint inflammation in rats with a model of rheumatoid arthritis without eliciting immunogenicity against ShK-235. This work demonstrates the efficacy of using the probiotic L. reuteri as a novel oral delivery platform for the peptide ShK-235 and provides an efficacious strategy to deliver other biologics with great translational potential.

Have Therapeutics Enhanced Our Knowledge of Axial Spondyloarthritis?

PURPOSE OF REVIEW

An overview of how the treatment landscape of axial spondyloarthritis (axSpA) has shaped our understanding of the disease.

RECENT FINDINGS

Prior to the millennium, non-steroidal anti-inflammatory drugs (NSAIDs) were the only treatment for axSpA, yet only 30% of patients responded and many developed side effects. In 2003, the first biological disease-modifying drug (bDMARD) was licensed for axSpA which substantially improved outcomes in comparison to NSAIDs. In 2022, there are now several bDMARDs for axSpA; however, they too are not universally efficacious in treating axial inflammation and may have deleterious effects on extramusculoskeletal manifestations. Nevertheless, successful or not, each bDMARD gives invaluable insight into axSpA immunobiology. This review discusses how much we have learned from the use of bDMARDs in axSpA, how this has redefined our understanding of the disease, and how we might use this knowledge to develop new and better treatments for axSpA in the future.

Therapeutic Protein Drug Interactions: A White Paper From the International Consortium for Innovation and Quality in Pharmaceutical Development

Typically, therapeutic proteins (TPs) have a low risk for eliciting meaningful drug interactions (DIs). However, there are select instances where TP drug interactions (TP-DIs) of clinical concern can occur. This white paper discusses the various types of TP-DIs involving mechanisms such as changes in disease state, target-mediated drug disposition, neonatal Fc receptor (FcRn), or antidrug antibodies formation. The nature of TP drug interaction being investigated should determine whether the examination is conducted as a standalone TP-DI study in healthy participants, in patients, or assessed via population pharmacokinetic analysis. DIs involving antibody-drug conjugates are discussed briefly, but the primary focus here will be DIs involving cytokine modulation. Cytokine modulation can occur directly by certain TPs, or indirectly due to moderate to severe inflammation, infection, or injury. Disease states that have been shown to result in indirect disease-DIs that are clinically meaningful have been listed (i.e., typically a twofold change in the systemic exposure of a coadministered sensitive cytochrome P450 substrate drug). Type of disease and severity of inflammation should be the primary drivers for risk assessment for disease-DIs. While more clinical inflammatory marker data needs to be collected, the use of two or more clinical inflammatory markers (such as C-reactive protein, albumin, or interleukin 6) may help broadly categorize whether the predicted magnitude of inflammatory disease-DI risk is negligible, weak, or moderate to strong. Based on current knowledge, clinical DI studies are not necessary for all TPs, and should no longer be conducted in certain disease patient populations such as psoriasis, which do not have sufficient systemic inflammation to cause a meaningful indirect disease-DI.

Trajectories of systemic agent use and associated depression- and anxiety-related health care costs among patients with psoriasis

Background

Systemic treatment patterns and related mental health disorders and economic burden among patients with psoriasis are largely unknown.

Objective

To assess systemic treatment patterns and associated depression and anxiety-related health care costs among patients with psoriasis initiating a conventional systemic treatment (CST).

Methods

Using a retrospective cohort design with sequence and cluster analyses, we assessed systemic treatment trajectories (CST and tumor necrosis factor inhibitors or ustekinumab, [TNFi/UST]) over a 2-year period following CST initiation. We compared health care costs between trajectories using 2-part models.

Results

We included 781 patients and identified 8 trajectories: persistent methotrexate users, persistent acitretin users, early CST discontinuation, late methotrexate discontinuation, switch to TNFi/UST, adding TNFi/UST, discontinuation then restart on methotrexate, and discontinuation then restart on acitretin or multiple CST switches. Overall, 165 (21%) patients incurred depression- and anxiety-related health care costs (median annual cost, CAN$56; quartiles, $14-$127). Compared with persistent methotrexate users, adding a TNFi/UST (cost ratio, 3.63; 95% CI, 1.47-5.97) and discontinuation then restart on acitretin or multiple switches between systemic agents (cost ratio, 13.3; 95% CI 5.76-22.47) had higher costs.

Limitations

Trajectory misclassification may have occured. These date represent an association, and causality cannot be inferred, particularly given the risk of confounding.

Conclusion

Depression- and anxiety-related health care costs were high among patients adding TNFi/UST and those discontinuing then restarting on acitretin or experiencing multiple switches between systemic agents.

Saudi Arabia consensus guidance for the diagnosis and management of adults with inflammatory bowel disease

Optimal management of inflammatory bowel disease (IBD) relies on a clear understanding and tailoring evidence-based interventions by clinicians in partnership with patients. This article provides concise guidelines for the management of IBD in adults, based on the most up-to-date information at the time of writing and will be regularly updated. These guidelines were developed by the Saudi Ministry of Health in collaboration with the Saudi Gastroenterology Association and the Saudi Society of Clinical Pharmacy. After an extensive literature review, 78 evidence-and expert opinion-based recommendations for diagnosing and treating ulcerative colitis and Crohn's disease in adults were proposed and further refined by a voting process. The consensus guidelines include the finally agreed on statements with their level of evidence covering different aspects of IBD diagnosis and treatment.

Proposal of International Council for Harmonization (ICH) Guideline for the Approval of Biosimilars

OBJECTIVES

Since the initial release of biosimilars 18 years ago, regulations for their licensing have changed considerably; however, there is no global consensus on these regulations. Establishing harmonized regulatory guidelines for the approval of biosimilars with support from the ICH, an independent, non-profit association under Swiss law, will significantly enhance the affordability of biological drugs.

METHODS

Regulatory guidelines from the Food and Drug Administration (FDA), European Medicines Agency (EMA), Medicines and Healthcare products Regulatory Agency (MHRA), and World Health Organization (WHO) were analyzed for historical changes and elements critical to the safety and efficacy of biosimilars.

RESULTS

Analysis of all EMA and FDA filings show that none of the animal testing and clinical efficacy testing failed because animals do not have the required receptors to initiate pharmacologic responses, and efficacy studies cannot be statistically powered to conclude any results. New analytical technologies will enable good biosimilarity determination, avoiding both tests.

CONCLUSION

Scientifically based ICH guidelines that remove redundant studies will reduce development costs, improve safety, and allow global drug distribution based on single compliance. These guidelines are particularly necessary for emerging countries lacking the expertise and resources to evaluate biosimilar filings.

Assessing Immunogenicity of Biologic Drugs in Inflammatory Joint Diseases: Progress Towards Personalized Medicine

Biologic drugs have greatly improved treatment outcomes of inflammatory joint diseases, but a substantial proportion of patients either do not respond to treatment or lose response over time. Drug immunogenicity, manifested as the formation of anti-drug antibodies (ADAb), constitute a significant clinical problem. Anti-drug antibodies influence the pharmacokinetics of the drug, are associated with reduced clinical efficacy, and an increased risk of adverse events such as infusion reactions. The prevalence of ADAb differs among drugs and diseases, and the detection of ADAb also depends on the assay format. Most data exist for the tumor necrosis factor-alpha inhibitors infliximab and adalimumab, with a frequency of ADAb that ranges from 10 to 60% across studies. Measurement of ADAb and serum drug concentrations, therapeutic drug monitoring, has been suggested as a strategy to optimize therapy with biologic drugs. Although the recent randomized clinical Norwegian Drug Monitoring (NOR-DRUM) trials show promise towards a personalized medicine prescribing approach by therapeutic drug monitoring, several challenges remain. A plethora of assay formats, with widely differing properties, is currently used for measuring ADAb. Comparing results between different assays and laboratories is difficult, which complicates the development of cut-offs necessary for guidelines and the implementation of ADAb measurements in clinical practice. With the possible exception of infliximab, limited data on clinical relevance and cost effectiveness exist to support therapeutic drug monitoring as a routine clinical strategy to monitor biologic drugs in inflammatory joint diseases. The aim of this review is to provide an overview of the characteristics and prevalence of ADAb, predisposing factors to ADAb formation, commonly used assessment methods, clinical consequences of ADAb, and the potential implications of ADAb assessments for everyday treatment of inflammatory joint diseases.

Case Report: Severe thrombocytopenia induced by adalimumab in rheumatoid arthritis: A case report and literature review

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by persistent joint inflammation. In recent decades, biological agents such as anti-tumor necrosis factor-α (TNF-α) drugs have been applied in the treatment of RA and it achieved great improvement. The treatment has its side effects, but severe thrombocytopenia is very rare. In this case report we described the occurrence of severe thrombocytopenia in a patient with RA who was treated with adalimumab. Specially, the symptoms of the RA are not significantly improved by adalimumab treatment and severe thrombocytopenia it induced is resistant to treatment. After receiving four doses of adalimumab, the patient’s platelet count dropped to 4 × 103/μl. We halted adalimumab and administered glucocorticoids, interleukins, and platelet transfusion. On the sixth day, the platelet count rose to 52 × 103/μl. Lab tests and bone marrow pictures were unremarkable. Patient was treated with prednisone for maintenance. On day 17, the platelet count declined to 12 × 103/μl. We started the patient on methylprednisolone and recombinant human thrombopoietin (rh-TPO), but the effect was not significant. On day 25, intravenous immune globulin (IVIG) was applied in place of the rh-TPO. On 29th day, the patient’s platelets returned to normal. We summarized the existing literature on thrombocytopenia induced by anti-TNF-α drugs. This case suggested immunoglobulins could be considered for the treatment of refractory thrombocytopenia.

Risk factors for anti-drug antibody formation to infliximab: Secondary analyses of a randomised controlled trial

BACKGROUND

Anti-drug antibodies (ADAb) frequently form early in the treatment course of infliximab and other tumour necrosis factor (TNF) inhibitors, leading to treatment failure and adverse events.

OBJECTIVE

To identify risk factors for ADAb in the early phase of infliximab treatment.

METHODS

Patients (n = 410) with immune-mediated inflammatory diseases who initiated infliximab treatment were included in the 38-week Norwegian Drug Monitoring Trial (NOR-DRUM) A and randomised 1:1 to therapeutic drug monitoring (TDM) or standard therapy. Serum levels of infliximab and ADAb were measured at each infusion. Possible risk factors for ADAb formation were assessed using logistic regression, adjusting for potential confounders.

RESULTS

ADAb were detected in 78 (19%) patients. A diagnosis of rheumatoid arthritis (RA) (odds ratio [OR], 1.9 [95% confidence interval [CI] 1.0-3.6]) and lifetime smoking (OR, 2.0 [CI 1.1-3.6]) were baseline risk factors, while baseline use of concomitant immunosuppressors (OR, 0.4 [CI 0.2-0.8]) and a diagnosis of spondyloarthritis (SpA) (OR, 0.4 [CI 0.2-0.8]) reduced the risk of ADAb. Higher disease activity during follow-up (OR, 1.1 [CI 1.0-1.1]) and "drug holidays" of more than 11 weeks (OR, 4.1 [CI 1.2-13.8]) increased the risk of ADAb, whereas higher infliximab doses (OR, 0.1 [CI 0.0-0.3) and higher serum infliximab concentrations (OR, 0.7 [CI 0.6-0.8]) reduced the risk of immunogenicity.

CONCLUSION

Several risk factors for ADAb formation during early-phase infliximab treatment were identified. This knowledge provides a basis for treatment strategies to mitigate the formation of ADAb and identify patients in whom these measures are of particular importance.

Validation Study of a New Random-Access Chemiluminescence Immunoassay Analyzer i-TRACK10® to Monitor Infliximab and Adalimumab Serum Trough Levels and Anti-Drug Antibodies

Background. Monitoring of biological TNF inhibitors is a very important tool to guide clinical decisions using specialized algorithms, especially in gastroenterology. A new chemiluminescent instrument (i-TRACK^10® from Theradiag) could replace ELISA techniques to calculate the dosage of drugs and anti-drug antibodies. In this bi-centric study, we explored the analytical performances of i-TRACK^10® using manual or automated (DS2^®) ELISA Lisa-Tracker^® assays, and compared the results. Patients and methods. Intra- and inter-run performances were evaluated with i-TRACK^10® in two different laboratories and for two different ranges of values for infliximab, adalimumab, and their respective antibodies. Patients’ samples were used in the labs to compare the results obtained between the new instrument and either the manual Lisa-Tracker^® or the automated DS2. Results. Intra- and inter-run performances were satisfactory, with values between 1.8% and 16.1% (for inter-run imprecision at low/medium values of infliximab). Results were generally comparable between assays. with the lowest value of correlation at 0.59 (anti-adalimumab dosage between i-TRACK^10® and manual ELISA). Most often, values of drugs and anti-drug antibodies were higher with i-TRACK^10® than with manual ELISA assay, and correlation values were better with automated ELISA. Agreements were globally acceptable, and the lowest coefficients of 0.7 was obtained for adalimumab values between i-TRACK^10® and the two ELISA methods, and for anti-adalimumab values between i-TRACK^10® and manual ELISA. The type of assay can potentially induce a change in the class of patients and lead to divergent therapeutic decisions. Conclusions. The new random-access instrument i-TRACK^10® presents many advantages in a routine laboratory: rapidity, the possibility of standardization, usability, and expansion of the measurement range. Despite the relatively good agreement of results, it is preferable to use the same assay in longitudinal follow-up of a patient, because quantitative results were not completely equivalent especially for anti-drug antibodies.

Under the Umbrella of Clinical Pharmacology: Inflammatory Bowel Disease, Infliximab and Adalimumab, and a Bridge to an Era of Biosimilars

Monoclonal antibodies (MAbs) have revolutionized the treatment of many chronic inflammatory diseases, including inflammatory bowel disease (IBD). IBD is a term that comprises two quite similar, yet distinctive, disorders—Crohn’s disease (CD) and ulcerative colitis (UC). Two blockbuster MAbs, infliximab (IFX) and adalimumab (ADL), transformed the pharmacological approach of treating CD and UC. However, due to the complex interplay of pharmacology and immunology, MAbs face challenges related to their immunogenicity, effectiveness, and safety. To ease the burden of IBD and other severe diseases, biosimilars have emerged as a cost-effective alternative to an originator product. According to the current knowledge, biosimilars of IFX and ADL in IBD patients are shown to be as safe and effective as their originators. The future of biosimilars, in general, is promising due to the potential of making the health care system more sustainable. However, their use is accompanied by misconceptions regarding their effectiveness and safety, as well as by controversy regarding their interchangeability. Hence, until a scientific consensus is achieved, scientific data on the long-term effectiveness and safety of biosimilars are needed.

An Engineered Monovalent Anti-TNF-α Antibody with pH-Sensitive Binding Abrogates Immunogenicity in Mice following a Single Intravenous Dose

Therapeutic Abs directed toward TNF-α display significant immunogenicity in humans, frequently leading to lower serum concentrations of the Ab that are associated with lower treatment efficacy. The enhanced incidence of immunogenicity observed with this class of therapeutics may be mediated by the expression of TNF-α as a homotrimer, both as a soluble serum protein and as a membrane-associated protein (mTNF-α) on the surface of dendritic cells. The TNF-α homotrimer enables the formation of polyvalent Ab-TNF-α immune complexes (ICs) that enhance binding to FcR and neonatal FcR. Polyvalent ICs and Ab bound to mTNF-α on the surface of dendritic cells can internalize, traffic to the lysosomes, and be processed for presentation by MHC molecules. To diminish immunogenicity caused by trafficking of ICs and mTNF-α to the lysosomes, we engineered a monovalent format of adalimumab with pH-sensitive binding to TNF-α. The engineered variant, termed AF-M2637, did not cross-link TNF-α trimers and consequently formed small, nonprecipitating ICs only. AF-M2637 bound TNF-α with high affinity at pH 7.4 (EC50 = 1.1 nM) and displayed a significantly faster dissociation rate than adalimumab at pH 6.0. No immune response to AF-M2637 was detected in mice following a single i.v. dose. In contrast, rapid immunization was detected following the injection of a single i.v. dose of adalimumab, monovalent adalimumab, or the bivalent form of the pH-sensitive variant. These data suggest that ICs and mTNF-α both contribute to the immunogenicity of adalimumab in mice and provide a general strategy for engineering less immunogenic therapeutic TNF-α Abs.