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Contains fulltext : 88618.pdf (Publisher’s version ) (Closed access) OBJECTIVES: To investigate the extent antibodies to adalimumab are formed in patients with plaque psoriasis and whether these antibodies have clinical consequences. Also, to examine the relationship between antibodies to adalimumab and adalimumab trough titers. DESIGN: Prospective observational cohort study. SETTING: Two Dutch dermatology departments in university hospitals. PATIENTS: All consecutive patients starting a regimen of adalimumab for chronic plaque psoriasis. Patients were screened and fulfilled the Dutch reimbursement criteria for adalimumab to treat psoriasis. INTERVENTION: Adalimumab treatment (per label). MAIN OUTCOME MEASURES: The titer of antibodies to adalimumab, the adalimumab trough concentration, and the Psoriasis Area and Severity Index at weeks 12 and 24. RESULTS: Antibodies to adalimumab were detected in 13 of 29 patients (45%) during 24 weeks of treatment. Differences in response rates among patients with low, high, and no titers of antibodies to adalimumab were significant at weeks 12 and 24 (P = .04 and P < .001, respectively). The median adalimumab trough concentrations varied significantly among patients with low, high, and no titers of antibodies to adalimumab (1.30 [range, 0.01-5.50], 0.0 [range, 0.0-0.0], and 9.6 [range, 0.0-22.6] mg/L, respectively; P < .001). At week 24, the median adalimumab trough concentrations also differed significantly among good responders, moderate responders, and nonresponders (9.7 [range, 0.0-22.6], 8.9 [range, 3.2-12.6], and 0.0 [range, 0.0-13.3] mg/L, respectively; P = .01). CONCLUSION: Antibodies to adalimumab are associated with lower serum adalimumab trough concentrations and with nonresponse or loss of response to adalimumab in patients with plaque psoriasis. 01 februari 2010

OBJECTIVE: To investigate how antibodies against anti-tumour necrosis factor (anti-TNF) agents influence response after switching from infliximab to adalimumab in rheumatoid arthritis (RA). METHODS: This cohort study consisted of 235 patients with RA, all treated with adalimumab. At baseline 52 patients (22%) had been previously treated with infliximab ('switchers'), and 183 (78%) were anti-TNF naive. Disease activity (using the 28-joint count Disease Activity Score (DAS28)) and presence of antibodies against infliximab and adalimumab were assessed. Clinical response to adalimumab was compared between switchers and anti-TNF naive patients and their anti-infliximab and anti-adalimumab antibody status. RESULTS: After 28 weeks of adalimumab treatment the decrease in DAS28 (Delta DAS28) for the 235 patients was 1.6+/-1.5 (mean+/-SD). Anti-adalimumab antibodies were detected in 46 patients (20%). Delta DAS28 was 1.8+/-1.4 in patients without anti-adalimumab and 0.6+/-1.3 in patients with anti-adalimumab (p

Background:Immunogenicity, specifically the onset of antibodies against tumour necrosis factor (TNF) blocking agents, seems to play an important role in non-response to treatment with these drugs.Objectives:To assess the relation of clinical response of ankylosing spondylitis (AS) to etanercept with etanercept levels, and the presence of antibodies to etanercept.Methods:Patients with AS were treated with etanercept 25 mg twice weekly, according to the international Assessment in Ankylosing Spondylitis (ASAS) working group consensus statement. Sera were collected at baseline and after 3 and 6 months of treatment. Clinical response was defined as a 50% improvement or as an absolute improvement of 2 points on a (0–10 scale) Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score. Functional etanercept levels were measured by a newly developed ELISA, measuring the binding of etanercept to TNF. Antibodies against etanercept were measured with a two-site assay and antigen binding test. Clinical data were used to correlate disease activity with serum etanercept levels.Results:In all, 53 consecutive patients were included. After 3 months of treatment 40 patients (76%) fulfilled the response criteria. Mean etanercept levels were 2.7 mg/litre and 3.0 mg/litre after 3 and 6 months respectively. Characteristics and etanercept levels of responders and non-responders were similar. No antibodies to etanercept were detected with any of the assays.Conclusion:Etanercept levels of responders and non-responders were similar and no antibodies to etanercept were detected with any of the assays. This study indicates that etanercept is much less immunogenic compared with the other TNF-blocking agents.

Objective Treatment of patients with infliximab, a chimeric monoclonal IgG1 antibody against tumor necrosis factor, may result in the formation of infliximab-specific IgG antibodies. This study evaluated the clinical significance of these antibodies in patients with rheumatoid arthritis (RA). Methods Antiinfliximab antibodies were measured using a newly developed radioimmunoassay in a cohort of 51 consecutive patients with RA treated with infliximab, with a followup of 1 year. In addition, serum infliximab levels were determined by enzyme-linked immunosorbent assay. The results were analyzed in relation to the clinical response to treatment according to the European League Against Rheumatism criteria. Results Antibodies against infliximab were detected in 22 patients (43%). Patients without detectable antiinfliximab antibodies (n = 29 [57%]) were significantly more often classified as responders (20 of 29 [69%]) compared with patients with detectable antiinfliximab antibodies (8 of 22 [36%]; P = 0.04). Three patients had an infusion-related allergic reaction, all of whom had detectable antiinfliximab antibodies. Conclusion In this study, nearly half of the RA patients treated with infliximab developed antiinfliximab antibodies within the first year of treatment. This seems to be clinically relevant, since development of antiinfliximab antibodies is associated with a reduced response to treatment.

Objective The most cost-effective dosing regimen for rituximab treatment in RA is currently unknown. The objective of this study is to determine whether low rituximab serum levels are associated with progression of structural damage in RA patients. Methods Sixty-two RA patients were treated with rituximab in three different centres. Structural damage was assessed on radiographs of hands and feet before and 1 year after therapy using the Sharp-van der Heijde scoring method (SHS). Patients were divided into progressors vs non-progressors based on different cut-off values. Rituximab serum levels were measured by sandwich ELISA after 4 and 12 weeks (Leiden University Medical Center and University Medical Centre, Utrecht cohorts) or 4 and 16 weeks (Academic Medical Center/University of Amsterdam cohort). Results There was no difference in rituximab levels between progressors and non-progressors 4 weeks and 12 or 16 weeks after initiation of treatment in the different cohorts. There was also no correlation between rituximab levels at week 4 or week 12 or 16 and change in SHS score after 1 year. Conclusion Low rituximab serum levels are not associated with progression of structural damage in RA patients. The results do not support the use of dosages higher than 2 × 1000 mg rituximab to inhibit progression of joint destruction.

Rheumatoid factors are antibodies directed against IgG that may confound immunogenicity testing for therapeutic monoclonal antibodies. We developed antigen-binding assays to monitor anti-drug-antibody (ADA) responses against infliximab and adalimumab using F(ab')2 fragments of the drug. This avoids possible detection of rheumatoid factor activity. During development of these assays, a number of sera from patients before treatment as well as several healthy control sera were tested positive. None of these sera contained antibodies specific for the therapeutic mAb. Instead, they were found to contain anti-hinge antibodies. We demonstrate that this aspecific antibody binding can be inhibited by adding F(ab')2 of intravenous immunoglobulin (IVIG), which consists of pooled polyclonal IgG derived from plasma. Using this protocol, anti-infliximab antibodies can be measured specifically without interference by anti-hinge antibodies. (C) 2011 Elsevier B.V. All rights reserved

Objective The aim of this study was to test the hypothesis that the reason for non-response (caused by immunogenicity or not) to a fi rst tumour necrosis factor (TNF) inhibitor defi nes whether a second TNF inhibitor will be effective. Methods This cohort study consisted of 292 consecutive patients with rheumatoid arthritis (RA), all treated with etanercept. A total of 89 patients (30%) were treated previously with infl iximab or adalimumab (‘switchers’), and the remaining 203 (70%) were anti-TNF naive. All switchers were divided into two groups: with and without antibodies against the previous biological. Differences in clinical response to etanercept between switchers with and without antibodies and patients who were anti-TNF naive were assessed after 28 weeks of treatment using changes in Disease Activity Score in 28 joints (DAS28). Results After 28 weeks of treatment, response to etanercept did not differ between patients who were anti-TNF naive and switchers with anti-drug antibodies (ΔDAS28=2.1±1.3 vs ΔDAS28=2.0±1.3; p=0.743). In contrast, switchers without anti-drug antibodies had a diminished response to etanercept treatment compared to patients who were TNF naive (ΔDAS28=1.2±1.3 vs ΔDAS28=2.1±1.3; p=0.001) and switchers with antibodies (ΔDAS28=1.2±1.3 vs ΔDAS28=2.0±1.3; p=0.017). Conclusion Patients with RA with an immunogenic response against a fi rst TNF-blocking agent had a better clinical response to a subsequent TNF blocker compared to patients with RA without anti-drug antibodies. Hence, determining immunogenicity can be helpful in deciding in which patient switching could be benefi cial and can be part of a personalised treatment regimen.

The aim was comparing the capability of a set of analytical methods to detect physical instability (focus on aggregation and structural changes) of etanercept during thermal stress testing as early as possible. Pre-filled syringes of Enbrel® 50 mg from three batches were thermally stressed for one week at 50 °C. Samples were taken at days 0, 1, 2, 3, 4 and 7, and analyzed with high-performance liquid size exclusion chromatography (HP-SEC), SDS–PAGE gel electrophoresis, dynamic light scattering (DLS), light obscuration, extrinsic fluorescence (Bis-ANS), far-UV circular dichroism (CD) spectroscopy, second derivative UV spectroscopy (UV), and enzyme-linked immunosorbent assay (ELISA). Thermal stress resulted in the formation of small soluble aggregates (HP-SEC, DLS) which were in part covalent (SDS–PAGE), and conformationally changed (Bis-ANS, CD, UV). No significant increase in subvisible particles was detected by light obscuration. An apparent increase in TNF-α binding to etancercept in the stressed formulations was found by ELISA. The three batches were comparable when unstressed, but showed slight differences in aggregation tendency. Bis-ANS fluorescence was most sensitive with respect to early-stage detection of heat-induced instability of etanercept (significant changes already at day 1), followed by HP-SEC (day 2) and DLS (day 3). This points towards a degradation mechanism involving exposure of hydrophobic patches due to partial unfolding followed by aggregation.

Objectives:To analyse whether persistence of synovial B lineage cells and lack of clinical response to rituximab treatment in patients with rheumatoid arthritis (RA) are associated with low rituximab serum levels and anti-rituximab antibody (ARA) formation.Methods:Fifty-eight patients with RA were treated with rituximab. The clinical response was determined 24 weeks after each treatment course using the Disease Activity Score evaluated in 28 joints (DAS28) and EULAR response criteria. Rituximab serum levels, ARAs and synovial B lineage cell numbers were determined before and after treatment.Results:Four weeks after treatment rituximab serum levels were highly variable. Low rituximab levels were associated with ARA formation (in five patients (8.6%)) and high baseline erythrocyte sedimentation rate. Interestingly, serum rituximab levels were not related to persistence of synovial B lineage cells or clinical response. Furthermore, response to treatment and re-treatment was similar in ARA-positive and ARA-negative patients.Conclusion:There is clear variability in serum levels after rituximab treatment, but rituximab levels are not lower in patients with persistence of synovial B lineage cells or lack of clinical response. The current treatment schedule suffices to induce and maintain a clinical response, even when ARAs are formed.

The development of anti-infliximab antibodies in 8% to 43% of infliximab-treated patients is associated with decreased efficiency and increased risk of adverse effects.1–3 An intervention that can diminish anti-infliximab antibody formation is therefore warranted. Rituximab, a chimeric monoclonal antibody that selectively depletes CD20-positive B lymphocytes, could potentially inhibit the human antibody response against infliximab. Therefore, we assessed the proportion of patients with rheumatoid arthritis (RA) in which treatment with rituximab resulted in the depletion of anti-infliximab antibodies. Consecutive patients with RA with detectable anti-infliximab antibodies, who were initiated on treatment with either rituximab or adalimumab, were included in this prospective controlled cohort study. …

BACKGROUND: A substantial proportion of patients with rheumatoid arthritis (RA) do not respond, or lose initial response, to adalimumab treatment. One explanation for non-response is that patients develop anti-adalimumab antibodies.OBJECTIVES: To evaluate the incidence of formation of antibody against adalimumab and the association with serum adalimumab concentrations and clinical response.METHODS: In a cohort of 121 consecutive patients with RA treated with adalimumab, serum adalimumab concentrations and antibodies against adalimumab were measured together with clinical response variables before and up to 28 weeks after the start of treatment.RESULTS: Anti-adalimumab antibodies were detected in 21 patients (17%) during 28 weeks of treatment. EULAR non-responders had antibodies significantly more often than good responders (34% vs 5%; p = 0.032). Patients with antibodies showed less improvement in disease activity (mean (SD) delta DAS28 0.65 (1.35)) than patients without antibodies (mean delta DAS28 1.70 (1.35)) (p = 0.001). Patients with antibodies during follow-up had lower serum adalimumab concentrations at 28 weeks than patients without antibodies (median 1.2 mg/l, range 0.0-5.6 vs median 11.0 mg/l, range 2.0-33.0, respectively; pCONCLUSIONS: Serum antibodies against adalimumab are associated with lower serum adalimumab concentrations and non-response to adalimumab treatment.

OBJECTIVES: Correlation of serum trough infliximab levels and antibodies to infliximab (anti-infliximab) with clinical response in ankylosing spondylitis. METHODS: In accordance with the international ASsessment in Ankylosing Spondylitis (ASAS) consensus statement, patients were treated with infliximab (5 mg/kg) every 6 weeks after a starting regimen. Preinfusion sera were collected at baseline, 24 and 54 weeks. At every visit, the 20% improvement response (ASAS-20) was assessed and laboratory tests performed. RESULTS: 24 of the 38 (63%) patients fulfilled ASAS-20 response criteria after 24 weeks of treatment and 21 (53%) after 54 weeks. After 54 weeks, 11 (29%) patients showed undetectable serum trough infliximab levels and detectable anti-infliximab; six of these patients developed an infusion reaction. Anti-infliximab was found significantly more often (p = 0.04) in ASAS-20 non-responders compared with responders at week 54. Serum trough infliximab levels were significantly (p

Tumour necrosis factor blocking agents such as infliximab have proved to be effective in patients with ankylosing spondylitis as up to 60–70% of the patients meet the 20% response criteria of assessment in ankylosing spondylitis (ASAS).1,2 However, it cannot be explained why 30% of patients fail to respond and develop adverse reactions. In rheumatoid arthritis, inefficacy to infliximab was associated with low serum trough infliximab levels and the presence of antibodies to infliximab (ATI).3 This study was designed to identify whether infliximab levels and ATI predict clinical inefficacy and adverse events in ankylosing spondylitis. Eight patients with active ankylosing spondylitis (fulfilling the 1984 modified New York Criteria …

Adalimumab is an effective treatment for rheumatoid arthritis. However, a substantial proportion of patients with rheumatoid arthritis either do not respond or lose their initial response.1 We report a patient who initially responded to adalimumab treatment, but in whom disease activity increased as treatment continued. We believe that this lack of response to adalimumab is probably caused by the formation of human anti-human antibodies (HAHAs). A 69-year-old woman with rheumatoid arthritis (diagnosed in 1991) and progressive joint destruction had active disease despite treatment with methotrexate 10 mg weekly and prednisone 7.5 mg/day. Therefore, treatment with adalimumab, 40 mg every other week, was started, in combination …

Background: Production of both antigen-specific immunoglobulin (Ig)E and IgG4 antibodies is dependent on stimulation of B cells by T helper 2 cell-derived cytokines. However, there is controversy as to their interaction. In this study, we investigated the interdependency of IgE and IgG4 antibody responses to a relatively high range of airway exposure to animal-derived proteins in an occupational setting. Moreover, associations with self-reported airway symptoms and bronchial hyperresponsiveness were established. Methods: In a cross-sectional design, employees of an animal plasma spray-drying factory were questioned about airway symptoms, exposure was measured with personal sampling technique, and serology was performed. In a selection of subjects from this population, serology was repeated 15 months later, and bronchial hyperresponsiveness was measured. Results: IgE and IgG4 antibodies were detected in 17 and 57% of all employees and were both associated with degree of exposure. Only IgE antibodies showed an independent association with self-reported airway symptoms and bronchial hyperresponsiveness. The presence of IgE antibodies was limited to employees with high levels of IgG4. Employees with IgE and symptoms appeared to have less IgG4 than asymptomatic IgE-positive individuals. The level of specific IgG4 antibodies was stable over a 15-month period. Conclusions: In high-range airway exposure, development of IgE and IgG4 antibodies depended on the level of exposure. The threshold for development of IgG4 antibodies appeared to be less than that for IgE antibodies, and IgG4 antibodies may protect against the development of symptoms.

While the majority of patients with psoriatic arthritis (PsA) respond well to treatment with adalimumab, some patients lose response.1 An explanation might be the development of antiadalimumab antibodies, which has been reported in rheumatoid arthritis.2 3 Therefore, we studied the incidence of antiadalimumab antibodies in PsA, and the relationship with serum adalimumab concentration and clinical response. Twenty-two patients with active PsA, fulfilling CASPAR classification criteria,4 started adalimumab treatment (table 1). The patients met the requirements of the Dutch consensus on initiation of tumour necrosis factor blocking therapy in PsA5 and were seen at baseline, and after 3 and 12 months. Serum samples were collected just before the next injection with adalimumab. The Disease Activity Score in 28 joints (DAS28), which has been shown to discriminate between active drug and placebo in clinical trials in …

Cat-allergic patients frequently have IgG antibodies directed against Fel d 1. The aim of this study was to investigate whether these IgG antibodies influence the results of the skin test. Titrated skin tests were performed with Fel d 1 and IgE and IgG antibody levels were measured in 59 patients with cat allergy. Levels of specific IgG against Fel d 1 ranged from less than 0.25 to 3.5 microgram/ml. By means of a multiple regression analysis it was shown that the amount of specific IgG antibodies contributes significantly to the results of the skin test. Presence of specific IgG against Fel d 1 was accompanied by higher skin thresholds for Fel d 1. In conclusion, this study indicates that even low levels of specific IgG, induced by natural exposure to cat allergens, have a blocking effect on the early phase skin reaction.