Patient-perspective and feasibility of home finger-prick testing to complement and facilitate large-scale research in rheumatology

BACKGROUND

During the COVID-19 pandemic, we developed a digital research platform to longitudinally investigate COVID-19-related outcomes in patients with rheumatic diseases and healthy controls. We used home finger-prick testing in order to collect serum samples remotely and increase the overall efficiency of the platform. The aim of the present study was to evaluate the success rate of the finger prick and patients' perspective towards the finger prick.

METHODS

Serum samples were collected up to five times during follow-up, either via a venepuncture at the research institute or a finger prick from participants' home. Participants were asked to complete a digital evaluation questionnaire of the finger prick after their attempts.

RESULTS

A total of 2135 patients and 899 controls performed at least one finger prick and were included in this study. The first finger prick was successfully done by 92% (95% CI: 90% to 93%) of patients, 94% (95% CI: 92% to 95%) of controls, 93% (95% CI: 92% to 94%) of all participants aged ≤70 years and 89% (95% CI: 86% to 92%) of all participants aged >70 years. Sex did not impact these success rates. Repeated failure occurred in 11/439 (0.8%) patients and 4/712 (0.6%) controls. Both patients and controls were less willing to perform a finger prick for individual healthcare compared with scientific research.

CONCLUSION

The vast majority of participants, among which elderly and patients with rheumatic diseases, were able to successfully draw the required amount of blood for serological analyses. This shows that finger-prick testing is suitable for a high-throughput implementation to monitor patients remotely.

Novel DNA methylome biomarkers associated with adalimumab response in rheumatoid arthritis patients

Background and aims

Rheumatoid arthritis (RA) patients are currently treated with biological agents mostly aimed at cytokine blockade, such as tumor necrosis factor-alpha (TNFα). Currently, there are no biomarkers to predict therapy response to these agents. Here, we aimed to predict response to adalimumab (ADA) treatment in RA patients using DNA methylation in peripheral blood (PBL).

Methods

DNA methylation profiling on whole peripheral blood from 92 RA patients before the start of ADA treatment was determined using Illumina HumanMethylationEPIC BeadChip array. After 6 months, treatment response was assessed according to the European Alliance of Associations for Rheumatology (EULAR) criteria for disease activity. Patients were classified as responders (Disease Activity Score in 28 Joints (DAS28) < 3.2 or decrease of 1.2 points) or as non-responders (DAS28 > 5.1 or decrease of less than 0.6 points). Machine learning models were built through stability-selected gradient boosting to predict response prior to ADA treatment with predictor DNA methylation markers.

Results

Of the 94 RA patients, we classified 49 and 43 patients as responders and non-responders, respectively. We were capable of differentiating responders from non-responders with a high performance (area under the curve (AUC) 0.76) using a panel of 27 CpGs. These classifier CpGs are annotated to genes involved in immunological and pathophysiological pathways related to RA such as T-cell signaling, B-cell pathology, and angiogenesis.

Conclusion

Our findings indicate that the DNA methylome of PBL provides discriminative capabilities in discerning responders and non-responders to ADA treatment and may therefore serve as a tool for therapy prediction.

Changes in Tumor Necrosis Factor Inhibitor Drug Survival in Patients With Rheumatoid Arthritis, Psoriatic Arthritis, and Ankylosing Spondylitis Over 15 Years

OBJECTIVE

To study changes in retention of first biologic disease-modifying antirheumatic drug (DMARD) therapy over a period of 15 years in an inception cohort of patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA), and ankylosing spondylitis (AS).

METHODS

We assessed patient and disease characteristics and drug survival of patients starting a biologic (tumor necrosis factor inhibitor [TNFi]) therapy between 2004 and 2019 in routine care at the Amsterdam Rheumatology and Immunology Center, Reade, the Netherlands. Starts were classified as early (2004-2008), intermediate (2009-2013), and recent (2014-2018). Kaplan-Meier plots and log-rank tests assessed the overall difference in drug survival between the 3 observation groups and between diagnoses, followed by Cox regression to estimate hazard ratios (HRs).

RESULTS

We included 1938 consecutive patients starting TNFi therapy, 63% with RA, 19% with PsA, and 19% with AS; 65% were female. Drug survival decreased significantly over time (overall P < 0.001), mostly caused by decreases in the most recent 4-year period. The HR for drug continuation was 2.04 (95% CI 1.71-2.43, P < 0.001) for the early vs the recent group and 1.92 (95% CI 1.58-2.35, P < 0.001) for the intermediate vs the recent group. Drug survival time was significantly different between diseases (overall P < 0.001), mostly caused by shorter survival in RA. The HR for drug continuation was 0.58 (95% CI 0.47-0.73, P < 0.001) for RA vs PsA and 0.63 (95% CI 0.51-0.78, P < 0.001) for RA vs AS.

CONCLUSION

Patients with RA, PsA, and AS currently initiating biologic (TNFi) therapy discontinue the drug much sooner than those starting shortly after the drugs were introduced. This is most likely because of the availability of alternative novel biologic and targeted synthetic DMARD treatments and treat-to-target protocols enabling and necessitating earlier switching.

Drug-tolerant detection of anti-drug antibodies in an antigen-binding assay using europium chelate fluorescence

Accurate anti-drug antibody (ADA) measurements in patient sera requires dissociation of ADA-drug complexes combined with sensitive and specific ADA detection. Bridging type immunoassays are often used despite several disadvantages associated with this approach. A good drug-tolerant alternative is the acid-dissociation radioimmunoassay (ARIA), but this method is not easily implemented in most labs as specialized facilities are required for working with radioactive materials. We describe an innovative method for ADA detection that combines the advantages of antigen binding tests like the ARIA with the convenience of regular immunoassays. This acid-dissociation lanthanide-fluorescence immunoassay (ALFIA) involves dissociation of ADA-drug complexes, followed by binding to an europium-labeled drug derivative and subsequently an IgG pulldown on Sepharose beads. After europium elution, detection is achieved by measuring time-resolved fluorescence originating from europium chelate complexes. We measured anti-adalimumab ADA levels in sera of 94 rheumatoid arthritis patients using the ALFIA and showed this method to be highly drug tolerant, sensitive and specific for anti-adalimumab ADAs.

OP0178 COVID-19 BREAKTHROUGH INFECTIONS IN VACCINATED PATIENTS WITH IMMUNE-MEDIATED INFLAMMATORY DISEASES AND CONTROLS – DATA FROM TWO PROSPECTIVE COHORT STUDIES

Background

Concerns have been raised regarding risks of COVID-19 breakthrough infections in vaccinated patients with immune-mediated inflammatory diseases (IMIDs) treated with immunosuppressants, but data on COVID-19 breakthrough infections in these patients are still scarce.

Objectives

The primary objective was to compare the incidence and severity of COVID-19 breakthrough infections with the SARS-CoV-2 delta variant between fully vaccinated IMID patients with immunosuppressants, and controls (IMID patients without immunosuppressants and healthy controls). The secondary objective was to explore determinants of breakthrough infections.

Methods

In this study we pooled data collected from two large ongoing prospective multi-center cohort studies (Target to-B! [T2B!] study and ARC study). Clinical data were collected between February and December 2021, using digital questionnaires, standardized electronic case record forms and medical files. Post-vaccination serum samples were analyzed for anti-RBD antibodies (T2B! study only) and anti-nucleocapsid antibodies to identify asymptomatic breakthrough infections (ARC study only). Logistic regression analyses were used to assess associations with the incidence of breakthrough infections. Multivariable models were adjusted for age, sex, cardiovascular disease, chronic pulmonary disease, obesity and vaccine type.

Results

We included 3207 IMID patients with immunosuppressants and 1810 controls (985 IMID patients without immunosuppressants and 825 healthy controls). The incidence of COVID-19 breakthrough infections was comparable between patients with immunosuppressants (5%) and controls (5%). The absence of SARS-CoV-2 IgG antibodies after COVID-19 vaccination was independently associated with an increased incidence of breakthrough infections (P 0.044). The proportion of asymptomatic COVID-19 breakthrough cases that were additionally identified serologically in the ARC cohort was comparable between IMID patients with immunosuppressants and controls; 66 (10%) of 695 patients vs. 64 (10%) of 647 controls. Hospitalization was required in 8 (5%) of 149 IMID patients with immunosuppressants and 5 (6%) of 86 controls with a COVID-19 breakthrough infection. Hospitalized cases were generally older, and had more comorbidities compared with non-hospitalized cases (Table 1). Hospitalization rates were significantly higher among IMID patients treated with anti-CD20 therapy compared to IMID patients using any other immunosuppressant (3 [23%] of 13 patients vs. 5 [4%] of 128 patients, P 0.041; Table 1).

Table 1.

Determinants of the severity of COVID-19 breakthrough infections.

Ambulatory care (n = 222)Hospitalized (n = 13)Group - no. (%)IMID patients with immunosuppressants141(64)8(62)IMID patients without immunosuppressants49(22)3(23)Healthy controls32(14)2(15)Patient characteristicsAge, years – mean (SD)51(14)60(11)Female sex – no. (%)143(64)4(31)Comorbidities – no. (%)Cardiovascular disease17(8)5(39)Chronic pulmonary disease17(8)4(31)Diabetes15(7)3(23)Obesity34(15)5(39)Immunosuppressants– no. (%)Methotrexate36(16)2(15)TNF inhibitor48(22)2(15)Anti-CD20 therapy13(6)3(23)Mycophenolate mofetil3(1)0(0)S1P modulator5(2)0(0)Other immunosuppressants70(32)3(23)

Conclusion

The incidence of COVID-19 breakthrough infections in IMID patients with immunosuppressants was comparable to controls, and infections were mostly mild. Anti-CD20 therapy might increase patients’ susceptibility to severe COVID-19 breakthrough infections, but traditional risk factors also continue to have a critical contribution to the disease course of COVID-19. Therefore, we argue that most patients with IMIDs should not necessarily be seen as a risk group for severe COVID-19, and that integrating other risk factors should become standard practice when discussing treatment options, COVID-19 vaccination, and adherence to infection prevention measures with patients.

Disclosure of Interests

None declared

POS1520-HPR RHEUMATOLOGY PATIENTS TREATED WITH A bDMARD PERSPECTIVE TOWARDS THERAPEUTIC DRUG MONITORING

Background

Therapeutic Drug Monitoring (TDM) is a tool to determine the optimal dose of a drug for individual patients using measurement of blood concentrations and, optionally, anti-drug antibodies (ADA). In the field of rheumatology interest in applying TDM is increasing. A recent study by Syversen et al., the NOR-DRUM B trail, supports TDM as a treatment strategy. This study showed that treatment with proactive TDM was more effective then treatment without TDM. Applying TDM creates a more personalized treatment for individual patients, therefore it is relevant to understand the patients perspective towards TDM.

Objectives

To study the perspective of rheumatology patients treated with a bDMARD in a personalized fashion using TDM.

Methods

Adult rheumatology patients from the Amsterdam Rheumatology and immunology Center who participate in the COVID-19 prospective cohort study (Nederlands Trial Register, trial ID NL8513) received a digital questionnaire which comprised, in addition to demographic items, of three TDM topics: familiarity, attitude and risk assessment.

Results

Participants were selected based on the following criteria: treatment with a bDMARD and a fully completed questionnaire (n=888). Table 1 shows characteristics of study population.

Table 1.

Characteristics of study population

Total N= 888Age, yr Mean (SD)55(13)Gender, female - N (%)575(65)Diagnosis* - N (%)RA511(58)PSA172(19)AS203(23)Axial and peripheral SpA21(3)Other17(2)bDMARD** - N (%)Adalimumab242(27)Etanercept352(40)Other297(33)

* Some patients reported more than one diagnosis

** Three patients reported more than one bDMARD

Sixty-six percent (n=582) of the participants had never heard of the concept ‘personalized dosing, using TDM’. After explaining the concept 60% (n=535) of the participants answered they have a positive attitude towards the concept (Figure 1). Participants with a positive attitude received a follow-up question. They were asked which of the following related aspects: individual dosing, costs, safety and other, they thought was most relevant regarding the concept. Multiple answers were possible. Ninety-four percent (n=502) reported as the main reason for having a positive attitude, that the treatment can be personally adjusted. The second and third reasons, respectively, were safety 43% (n=230) and costs 27% (n=142) of the treatment.

Figure 1.

Attitude towards concept of TDM against being familiar with concept of TDM

Five percent (n=43) of the participants had a negative attitude towards the concept. Main reasons were; previous experience with unsuccessful dose reduction and unwillingness to change current treatment due to the fact that several previous treatments were ineffective.

Participants were also asked what amount of risk they are willing to take when presented with five different situations; worsening rheumatologically symptoms: e.g. pain and swelling, increased fatigability, necessary treatment with prednisone, switching to another bDMARD or more frequent visits to rheumatologist. Majority of the patients reported for each of the five situations, respectively: 37% (n=330), 40% (n=359), 51% (n=453), 48% (n= 426) and 29% (n=262) that they would only be willing to take a negligible risk, < 0.1%.

Conclusion

Majority of participants was not familiar with the concept of personalized dosing using TDM. However, the majority had a positive attitude towards the concept. The main reason for a positive attitude is that the treatment can be personally adjusted. On the other hand, patients who are currently being treated with a bDMARD were only willing to take a negligible risk when it comes to their own treatment.

References

[1]Syversen, S. W., Jorgensen, K. K., Goll, G. L., Brun, M. K., Sandanger, O., Bjorlykke, K. H., Haavardsholm, E. A. (2021). Effect of Therapeutic Drug Monitoring vs Standard Therapy During Maintenance Infliximab Therapy on Disease Control in Patients With Immune-Mediated Inflammatory Diseases: A Randomized Clinical Trial. JAMA, 326(23), 2375-2384. doi:10.1001/jama.2021.21316

Disclosure of Interests

Maureen Leeuw: None declared, Sadaf Atiqi: None declared, Fenna de Vries: None declared, Laura Boekel: None declared, Femke Hooijberg: None declared, Michael Nurmohamed Speakers bureau: Abbvie, Jansen, Celgene, Consultant of: Abbvie, Grant/research support from: Abbvie, Amgen, Pfizer, Galapagos, BMS, Gert-Jan Wolbink: None declared, Charlotte Krieckaert: None declared

Breakthrough SARS-CoV-2 infections with the delta (B.1.617.2) variant in vaccinated patients with immune-mediated inflammatory diseases using immunosuppressants: a substudy of two prospective cohort studies

Background

Concerns have been raised regarding the risks of SARS-CoV-2 breakthrough infections in vaccinated patients with immune-mediated inflammatory diseases treated with immunosuppressants, but clinical data on breakthrough infections are still scarce. The primary objective of this study was to compare the incidence and severity of SARS-CoV-2 breakthrough infections between patients with immune-mediated inflammatory diseases using immunosuppressants, and controls (patients with immune-mediated inflammatory diseases not taking immunosuppressants and healthy controls) who had received full COVID-19 vaccinations. The secondary objective was to explore determinants of breakthrough infections of the delta (B.1.617.2) variant of SARS-CoV-2, including humoral immune responses after vaccination.

Methods

In this substudy, we pooled data collected in two large ongoing prospective multicentre cohort studies conducted in the Netherlands (Target to-B! [T2B!] study and Amsterdam Rheumatology Center COVID [ARC-COVID] study). Both studies recruited adult patients (age ≥18 years) with immune-mediated inflammatory diseases and healthy controls. We sourced clinical data from standardised electronic case record forms, digital questionnaires, and medical files. We only included individuals who were vaccinated against SARS-CoV-2. For T2B!, participants were recruited between Feb 2 and Aug 1, 2021, and for ARC-COVID, participants were recruited between April 26, 2020, and March 1, 2021. In this study we assessed data on breakthrough infections collected between July 1 and Dec 15, 2021, a period in which the delta SARS-CoV-2 variant was the dominant variant in the Netherlands. We defined a SARS-CoV-2 breakthrough infection as a PCR-confirmed or antigen test-confirmed SARS-CoV-2 infection that occurred at least 14 days after vaccination. All breakthrough infections during this period were assumed to be due to the delta variant due to its dominance during the study period. We analysed post-vaccination serum samples for anti-receptor binding domain (RBD) antibodies to assess the humoral vaccination response (T2B! study only) and anti-nucleocapsid antibodies to identify asymptomatic breakthrough infections (ARC-COVID study only). We used multivariable logistic regression analyses to explore potential clinical and humoral determinants associated with the odds of breakthrough infections. The T2B! study is registered with the Dutch Trial Register, Trial ID NL8900, and the ARC-COVID study is registered with Dutch Trial Register, trial ID NL8513.

Findings

We included 3207 patients with immune-mediated inflammatory diseases who receive immunosuppressants, and 1807 controls (985 patients with immune-mediated inflammatory disease not on immunosuppressants and 822 healthy controls). Among patients receiving immunosuppressants, mean age was 53 years (SD 14), 2042 (64%) of 3207 were female and 1165 (36%) were male; among patients not receiving immunosuppressants, mean age was 54 years (SD 14), 598 (61%) of 985 were female and 387 (39%) were male; and among healthy controls, mean age was 57 years (SD 13), 549 (67%) of 822 were female and 273 (33%) were male. The cumulative incidence of PCR-test or antigen-test confirmed SARS-CoV-2 breakthrough infections was similar in patients on immunosuppressants (148 of 3207; 4·6% [95% CI 3·9–5·4]), patients not on immunosuppressants (52 of 985; 5·3% [95% CI 4·0–6·9]), and healthy controls (33 of 822; 4·0% [95% CI 2·8–5·6]). There was no difference in the odds of breakthrough infection for patients with immune-mediate inflammatory disease on immunosuppressants versus combined controls (ie, patients not on immunosuppressants and healthy controls; adjusted odds ratio 0·88 [95% CI 0·66–1·18]). Seroconversion after vaccination (odds ratio 0·58 [95% CI 0·34–0·98]; T2B! cohort only) and SARS-CoV-2 infection before vaccination (0·34 [0·18–0·56]) were associated with a lower odds of breakthrough infections.

Interpretation

The incidence and severity of SARS-CoV-2 breakthrough infections in patients with immune-mediated inflammatory diseases on immunosuppressants was similar to that in controls. However, caution might still be warranted for those on anti-CD20 therapy and those with traditional risk factors.

Funding

ZonMw (the Netherlands Organization for Health Research and Development) and Reade foundation.

POS0659 LONG-TERM DYNAMICS OF ANTIBODY RESPONSE TO ADALIMUMAB DETECTED WITH A DRUG TOLERANT ASSAY

Background

Immunogenicity of adalimumab (ADL) has been the subject of extensive research, with the primary focus on its incidence, antibody titers and effects on clinical outcome. However, the temporal evolution of antibodies, i.e. dynamic and variation in titers, time point of emergent and persistence or transience of the response, remains under elucidated. To investigate this further, it is essential to collect samples at regular intervals and over a longer period of time. Also, a drug tolerant assay should be used to conquer with the phenomenon of drug interference (1).

Objectives

To evaluate the temporal evolution and to distinguish dynamic patterns of antibody response. Secondly, to assess the clinical impact and factors influencing these dynamic patterns.

Methods

ADA and adalimumab concentration were measured in sera of 511 consecutive ADL treated rheumatoid arthritis patients. Serum samples were drawn at week 0, 4, 16, 28, 52, 78 and 104. ADA were measured with a drug tolerant assay (Acid dissociation RadioImmunoAssay). Logistic regression analysis was carried out. Benjamini-Hochberg was used to correct for multiple testing.

Results

Baseline characteristics are depicted in Table 1. Fifty-nine percent of patients (n=300) developed ADA. Based on visual observations patients were clustered in 9 groups, taking the next features in to account (Figure 1); the presence or absence of ADA, the height of ADA titers (higher or lower than 100AU/mL), emergent (early vs. late; cutoff week 28) and its persistence. Based on these features 397 (77%) patients were assigned to one of the groups. Due to missing data at crucial time points the remainder of patients were excluded. In the ‘High early’ and High early LTF’ group was the rate of MTX use (adjusted odds ratio (AOR) 0.033 [95%CI 0.01-0.09] P<0.0001 respectively 0.79 [95%CI 0.03-0.22] P <0.0001), adalimumab concentration above 5mg/L (AOR 0.022[95%CI 0.01-0.08] P<0.001 respectively 0.026 [95%CI 0.01-0.09] P<0.001) and low disease activity (DAS28 <3.2) at week 52 (AOR 0.191[95%CI 0.07-0.56] P<0.002 respectively 0.102 [95%CI 0.03-0.31] P<0.001) significantly lower, compared to the negative group. Furthermore, the failure rate was in both groups significantly higher (AOR 9.19 [95%CI 3.7-22.87] P<0.0001 respectively 23.94 [95%CI 8.13-70.53] P<0.0001). In contrast to forgoing studies, our data does not show any differences in clinical outcomes between groups with persistent and transient ADA response.

Table 1.

Baseline characteristics

Totaal N=511Follow-upMedian weeks (IQR)78 (28-104)DemographicsAge mean SD53,7; ± 12,5Female No (%)409 (79.8)Disease statusDisease duration years median (IQR)6,7 (3-13)IgM rheumatoid factor + (%)327 (68.2)Anti-citrullinated protein antibody + (%)315 (73.2)Erosive (%)296 (61.6)DAS28-score mean SD4.5 ± 1.5MedicationMethotrexate use no (%)378 (73)

Conclusion

The majority of patients have an immune response to ADL. Based on ADA concentration, time point of emergence and its persistence, certain patterns of ADA response can be distinguished. Only high ADA concentration at early time points, causing low ADL concentration, are associated with unfavorable clinical effects. All the remaining distinctive patterns does not have any association with clinical outcomes. This suggests a regulated immune response in the majority of patients.

References

[1]Atiqi S, Hooijberg F, Loeff FC, Rispens T, Wolbink GJ. Immunogenicity of TNF-Inhibitors. Front Immunol. 2020 Feb 26;11:312. doi:10.3389/fimmu.2020.00312. PMID: 32174918; PMCID: PMC7055461

Disclosure of Interests

Sadaf Atiqi: None declared, Maureen Leeuw: None declared, Femke Hooijberg: None declared, Laura Boekel: None declared, Floris Loeff: None declared, Karien Bloem: None declared, Charlotte Krieckaert: None declared, Annick de Vries: None declared, Michael Nurmohamed Speakers bureau: AbbVie, Bristol-Myers Squibb, Eli Lilly, Roche, and Sanofi, Grant/research support from: AbbVie, Bristol-Myers Squibb, Celgene, Eli Lilly, Janssen, MSD, Mundipharma, Novartis, Pfizer, Roche, and Sanof, Theo Rispens Speakers bureau: AbbVie, Pfizer, and Regeneron, Grant/research support from: Genmab, Gert-Jan Wolbink Speakers bureau: UCB, Pfizer, AbbVie, Biogen and BMS, Grant/research support from: Pfeizer (paid to institution)

Antibody development and disease severity of COVID-19 in non-immunised patients with rheumatic immune-mediated inflammatory diseases: data from a prospective cohort study

Background

Research on the disease severity of COVID-19 in patients with rheumatic immune-mediated inflammatory diseases (IMIDs) has been inconclusive, and long-term prospective data on the development of SARS-CoV-2 antibodies in these patients are lacking.

Methods

Adult patients with rheumatic IMIDs from the Amsterdam Rheumatology and Immunology Center, Amsterdam were invited to participate. All patients were asked to recruit their own sex-matched and age-matched control subject. Clinical data were collected via online questionnaires (at baseline, and after 1–4 and 5–9 months of follow-up). Serum samples were collected twice and analysed for the presence of SARS-CoV-2-specific antibodies. Subsequently, IgG titres were quantified in samples with a positive test result.

Findings

In total, 3080 consecutive patients and 1102 controls with comparable age and sex distribution were included for analyses. Patients were more frequently hospitalised compared with controls when infected with SARS-CoV-2; 7% vs 0.7% (adjusted OR: 7.33, 95% CI: 0.96 to 55.77). Only treatment with B-cell targeting therapy was independently associated with an increased risk of COVID-19-related hospitalisation (adjusted OR: 14.62, 95% CI: 2.31 to 92.39). IgG antibody titres were higher in hospitalised compared with non-hospitalised patients, and slowly declined with time in similar patterns for patients in all treatment subgroups and controls.

Interpretation

We observed that patients with rheumatic IMIDs, especially those treated with B-cell targeting therapy, were more likely to be hospitalised when infected with SARS-CoV-2. Treatment with conventional synthetic disease-modifying antirheumatic drugs (DMARDs) and biological DMARDs other than B-cell targeting agents is unlikely to have negative effects on the development of long-lasting humoral immunity against SARS-CoV-2.

Immunogenicity of TNF-Inhibitors

Tumor necrosis factor inhibitors (TNFi) have significantly improved treatment outcome of rheumatic diseases since their incorporation into treatment protocols two decades ago. Nevertheless, a substantial fraction of patients experiences either primary or secondary failure to TNFi due to ineffectiveness of the drug or adverse reactions. Secondary failure and adverse events can be related to the development of anti-drug antibodies (ADA). The earliest studies that reported ADA toward TNFi mainly used drug-sensitive assays. Retrospectively, we recognize this has led to an underestimation of the amount of ADA produced due to drug interference. Drug-tolerant ADA assays also detect ADA in the presence of drug, which has contributed to the currently reported higher incidence of ADA development. Comprehension and awareness of the assay format used for ADA detection is thus essential to interpret ADA measurements correctly. In addition, a concurrent drug level measurement is informative as it may provide insight in the extent of underestimation of ADA levels and improves understanding the clinical consequences of ADA formation. The clinical effects are dependent on the ratio between the amount of drug that is neutralized by ADA and the amount of unbound drug. Pharmacokinetic modeling might be useful in this context. The ADA response generally gives rise to high affinity IgG antibodies, but this response will differ between patients. Some patients will not reach the phase of affinity maturation while others generate an enduring high titer high affinity IgG response. This response can be transient in some patients, indicating a mechanism of tolerance induction or B-cell anergy. In this review several different aspects of the ADA response toward TNFi will be discussed. It will highlight the ADA assays, characteristics and regulation of the ADA response, impact of immunogenicity on the pharmacokinetics of TNFi, clinical implications of ADA formation, and possible mitigation strategies.

Diurnal rhythms in the white adipose tissue transcriptome are disturbed in obese individuals with type 2 diabetes compared with lean control individuals

AIMS/HYPOTHESIS

Animal studies have indicated that disturbed diurnal rhythms of clock gene expression in adipose tissue can induce obesity and type 2 diabetes. The importance of the circadian timing system for energy metabolism is well established, but little is known about the diurnal regulation of (clock) gene expression in obese individuals with type 2 diabetes. In this study we aimed to identify key disturbances in the diurnal rhythms of the white adipose tissue transcriptome in obese individuals with type 2 diabetes.

METHODS

In a case-control design, we included six obese individuals with type 2 diabetes and six healthy, lean control individuals. All participants were provided with three identical meals per day for 3 days at zeitgeber time (ZT, with ZT 0:00 representing the time of lights on) 0:30, 6:00 and 11:30. Four sequential subcutaneous abdominal adipose tissue samples were obtained, on day 2 at ZT 15:30, and on day 3 at ZT 0:15, ZT 5:45 and ZT 11:15. Gene expression was measured using RNA sequencing.

RESULTS

The core clock genes showed reduced amplitude oscillations in the individuals with type 2 diabetes compared with the healthy control individuals. Moreover, in individuals with type 2 diabetes, only 1.8% (303 genes) of 16,818 expressed genes showed significant diurnal rhythmicity, compared with 8.4% (1421 genes) in healthy control individuals. Enrichment analysis revealed a loss of rhythm in individuals with type 2 diabetes of canonical metabolic pathways involved in the regulation of lipolysis. Enrichment analysis of genes with an altered mesor in individuals with type 2 diabetes showed decreased activity of the translation initiating pathway 'EIF2 signaling'. Individuals with type 2 diabetes showed a reduced diurnal rhythm in postprandial glucose concentrations.

CONCLUSIONS/INTERPRETATION

Diurnal clock and metabolic gene expression rhythms are decreased in subcutaneous adipose tissue of obese individuals with type 2 diabetes compared with lean control participants. Future investigation is needed to explore potential treatment targets as identified by our study, including clock enhancement and induction of EIF2 signalling.

DATA AVAILABILITY

The raw sequencing data and supplementary files for rhythmic expression analysis and Ingenuity Pathway Analysis have been deposited in NCBI Gene Expression Omnibus (GEO series accession number GSE104674).

Residual disease activity and treatment adjustments in psoriatic arthritis in current clinical practice

BACKGROUND

With expanding therapeutic possibilities for treatment of psoriatic arthritis (PsA) it will be increasingly important to determine residual disease and define when to adjust treatment. The rationale behind treatment decisions in current daily clinical practice and the relationship with residual disease activity has not been investigated. The aim of this study was to assess current clinical practice on defining residual disease and subsequent treatment decisions made in PsA patients.

METHODS

This cross-sectional study scored disease activity and treatment decisions prospectively in 142 consecutive PsA patients visiting the outpatient clinic for routine follow up. Disease activity parameters were scored by patient and the treating rheumatologist; the rheumatologist additionally registered his opinion on the presence of remaining disease activity despite current treatment (further mentioned as remaining disease) and subsequent treatment decisions.

RESULTS

Two thirds (90/142) of patients had remaining disease activity according to the treating rheumatologist. Almost half (46%) of these patients had moderate to high disease activity according to the clinical Disease Activity Index for Psoriatic Arthritis (cDAPSA). Residual disease activity was determined by joint disease and pain rather than by active psoriasis. Demographic and clinical features were similar between groups with or without residual disease. Among patients with remaining disease activity, 74% were treated with either a conventional synthetic disease-modifying anti-rheumatic drug (csDMARD) only or a first TNF-inhibiting biological agent, suggesting opportunities for treatment modification. However, treatment adjustment was initiated in only 21 (23%) of the 90 patients with residual disease. When comparing patients with remaining disease activity with and without treatment adjustment, we found no differences in objective disease activity measures, such as joint counts and patient scores. These data suggest that treatment is not adjusted in a large majority of patients with residual disease activity, although options for treatment changes are available.

CONCLUSIONS

Remaining disease activity is present in almost two thirds of patients with PsA when scored by the treating rheumatologist, but triggers treatment adjustment in only a minority. Further research to understand why disease activity does not lead to treatment adjustment is required to enable implementation of treatment strategies in clinical practice.