HLA-DQA1∗05 Genotype and Immunogenicity to Tumor Necrosis Factor-α Antagonists: A Systematic Review and Meta-analysis.

BACKGROUND & AIMS: Identifying patients at high risk of immunogenicity is important when selecting tumor necrosis factor (TNF)-α antagonists in patients with immune-mediated inflammatory diseases (IMIDs). We evaluated the association HLA-DQA1∗05 genotype and risk of immunogenicity with TNF-α antagonists. METHODS: Through a systematic review through July 14, 2022, we identified studies in patients with IMIDs treated with TNF-α antagonists, which reported the risk of immunogenicity and/or secondary loss of response in patients with HLA-DQA1∗05 variants. Primary outcome was risk of immunogenicity. We performed random effects meta-analysis and used GRADE to appraise certainty of evidence. RESULTS: On meta-analysis of 13 studies (3756 patients; median follow-up, 12 months; 41% with variants), HLA-DQA1∗05 variants were associated with 75% higher risk of immunogenicity compared with non-carriers (relative risk, 1.75; 95% confidence interval, 1.37-2.25) with considerable heterogeneity (I2 = 62%) (low certainty evidence). Positive and negative predictive values of HLA-DQA1∗05 variants for predicting immunogenicity were 30% and 80%, respectively. Proactive therapeutic drug monitoring, but not concomitant use of IMMs, IMIDs, and TNF-α antagonist-type, modified this association. Patients with HLA-DQA1∗05 variants experienced 2.2-fold higher risk of secondary loss of response (6 cohorts; relative risk, 2.24; 95% confidence interval, 1.67-3.00; I2 = 0%) (moderate certainty evidence). CONCLUSION: Variants in HLA-DQA1∗05 are associated with an increased risk in immunogenicity and secondary loss of response in patients with IMIDs treated with TNF-α antagonists. However, the positive and negative predictive value is moderate, and decisions on concomitant use of IMMs to prevent immunogenicity should be individualized based on all factors that influence drug clearance.

Proactive Therapeutic Drug Monitoring Versus Conventional Management for Inflammatory Bowel Diseases: A Systematic Review and Meta-Analysis.

BACKGROUND & AIMS: Proactive therapeutic drug monitoring (TDM) has been proposed to improve outcomes in patients with inflammatory bowel disease (IBD) treated with tumor necrosis factor (TNF)α antagonists. We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing proactive TDM with conventional management in patients with IBD. METHODS: We identified RCTs in patients with IBD treated with TNFα antagonists comparing proactive TDM (routine assessments of trough concentration with dose adjustments to maintain predetermined trough concentration, regardless of disease activity) with conventional management (clinically driven dose adjustments). The primary outcome was failure to maintain clinical remission. Certainty of evidence was appraised using Grading of Recommendations, Assessment, Development and Evaluations. RESULTS: On meta-analysis of 9 RCTs (8 RCTs in adults, and focusing on maintenance phase), there was no significant difference in the risk of failing to maintain clinical remission in patients who underwent proactive TDM (267/709; 38%) vs conventional management (292/696; 42%) (relative risk [RR], 0.96; 95% confidence interval [CI], 0.81-1.13) with moderate heterogeneity (inconsistency index = 36%) (Grading of Recommendations, Assessment, Development and Evaluations; low certainty evidence), with no differences in patients with Crohn's disease (RR, 0.87 ; 95% CI, 0.66-1.15) and ulcerative colitis (RR, 0.88; 95% CI, 0.72-1.07). Disease duration, concomitant immunomodulators, disease activity at baseline, and optimization of therapy before randomization did not modify this association. No differences were observed in risk of developing antidrug antibodies or serious adverse events. Patients in the proactive TDM arm were more likely to undergo dose escalation (RR, 1.56; 95% CI, 1.25-1.94). CONCLUSIONS: Routine proactive TDM to target biologic concentration to specific thresholds, regardless of disease activity, did not offer clinical benefit in patients with IBD treated with TNFα antagonists in RCTs conducted to date. We cannot exclude the possibility of benefit in disease subtypes and phases of therapy (induction) not represented in these RCT populations.

Rheumatoid factor and falsely elevated results in commercial immunoassays: data from an early arthritis cohort.

The aim of the study was to  assess RF cross-reactivity to animal antibodies used in immunoassays, and to test if selected commercial immunoassays are vulnerable to interference from RF, causing false test results. Our study included samples from patients with RF-positive rheumatoid arthritis (RA) and controls (patients with RF-negative RA and psoriatic arthritis), included in an early arthritis-cohort. Reactivity to mouse IgG1, mouse IgG2a, rabbit IgG, bovine IgG, sheep/goat IgG and human IgG was analysed using in-house interference assays. RF-positive sera with strong reactivity to mouse IgG1 were analysed in three commercial immunoassays. To reveal interference, results before and after addition of blocking aggregated murine IgG1 were compared. Samples from 124 RF-positive RA patients and 66 controls were tested. We found considerably stronger reactivity toward animal antibodies, particularly mouse IgG1 (73% vs. 12%) and rabbit IgG (81% vs. 6%), in sera from RF-positive RA-patients compared to controls (p < 0.001). After selecting samples for testing in commercial assays, interference was revealed in 6/30 sera in the Architect ß-hCG assay, 7/10 sera in the 27-plex cytokine assays, and in 2/33 samples in the Elecsys Soluble Transferrin Receptor assay. Our study revealed considerable RF reactivity to animal antibodies used in immunoassays and RF was associated with falsely elevated results in immunoassays used in clinical care and research. Clinicians, laboratorians, researchers and assay manufacturers must be alert to the risk of falsely elevated test results in RF-positive RA patients.

Association between high plasma levels of hepatocyte growth factor and progression of radiographic damage in the joints of patients with rheumatoid arthritis.

OBJECTIVE: Hepatocyte growth factor (HGF) and dickkopf-1 (Dkk-1) inhibit osteoblast differentiation. The present study was thus undertaken to investigate whether plasma levels of HGF and Dkk-1 are related to bone damage in patients with rheumatoid arthritis (RA). METHODS: RA patients with a disease duration of <4 years were followed up prospectively with collection of demographic, clinical, and radiographic data at study enrollment (1992) and after 1, 2, 5, and 10 years. Hand radiographs were scored according to the modified Sharp/van der Heijde score (SHS). Levels of HGF and Dkk-1 in stored plasma samples obtained from 136 patients at the time of enrollment were measured by enzyme-linked immunosorbent assay. Associations between cytokine levels and radiographic progression were examined by linear regression analysis. RESULTS: Patients with above-median levels of HGF at enrollment had a significantly greater change in the SHS after 1, 2, 5, and 10 years than did patients with below-median levels of HGF (P < 0.001, P = 0.006, P = 0.01, and P = 0.01, respectively). In an unadjusted analysis, baseline HGF levels predicted the severity of joint damage at all time points studied. After adjustment for other known predictors of radiographic progression, baseline HGF levels remained significantly associated with radiographic progression. Plasma levels of Dkk-1 at enrollment were not significantly associated with radiographic progression at any time point studied. CONCLUSION: Plasma levels of HGF predict joint damage in RA, and this finding suggests that HGF plays a role in RA joint destruction. The role of HGF as a potential prognostic biomarker or target for treatment warrants further exploration.

Immunogenicity and Safety of Standard and Third-Dose SARS-CoV-2 Vaccination in Patients Receiving Immunosuppressive Therapy.

OBJECTIVE: Immunogenicity and safety following receipt of the standard SARS-CoV-2 vaccination regimen in patients with immune-mediated inflammatory diseases (IMIDs) are poorly characterized, and data after receipt of the third vaccine dose are lacking. The aim of the study was to evaluate serologic responses and adverse events following the standard 2-dose regimen and a third dose of SARS-CoV-2 vaccine in IMID patients receiving immunosuppressive therapy. METHODS: Adult patients receiving immunosuppressive therapy for rheumatoid arthritis, spondyloarthritis, psoriatic arthritis, Crohn's disease, or ulcerative colitis, as well as healthy adult controls, who received the standard 2-dose SARS-CoV-2 vaccination regimen were included in this prospective observational study. Analyses of antibodies to the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein were performed prior to and 2-4 weeks after vaccination. Patients with a weak serologic response, defined as an IgG antibody titer of ≤100 arbitrary units per milliliter (AU/ml) against the receptor-binding domain of the full-length SARS-Cov-2 spike protein, were allotted a third vaccine dose. RESULTS: A total of 1,505 patients (91%) and 1,096 healthy controls (98%) had a serologic response to the standard regimen (P < 0.001). Anti-RBD antibody levels were lower in patients (median 619 AU/ml interquartile range [IQR] 192-4,191) than in controls (median 3,355 AU/ml [IQR 896-7,849]) (P < 0.001). The proportion of responders was lowest among patients receiving tumor necrosis factor inhibitor combination therapy, JAK inhibitors, or abatacept. Younger age and receipt of messenger RNA-1273 vaccine were predictors of serologic response. Of 153 patients who had a weak response to the standard regimen and received a third dose, 129 (84%) became responders. The vaccine safety profile among patients and controls was comparable. CONCLUSION: IMID patients had an attenuated response to the standard vaccination regimen as compared to healthy controls. A third vaccine dose was safe and resulted in serologic response in most patients. These data facilitate identification of patient groups at risk of an attenuated vaccine response, and they support administering a third vaccine dose to IMID patients with a weak serologic response to the standard regimen.

Distinct ACPA fine specificities, formed under the influence of HLA shared epitope alleles, have no effect on radiographic joint damage in rheumatoid arthritis.

OBJECTIVES: Human leucocyte antigen shared epitope (SE) alleles are associated with joint destruction, the presence of anticitrullinated protein antibodies (ACPA) and the ACPA fine specificity repertoire in rheumatoid arthritis (RA). A large variation in joint destruction is seen within the ACPA-positive patient population, and it is conceivable that certain ACPA reactivities contribute to radiological damage. The authors investigated whether ACPA fine specificities, which are formed under the influence of SE alleles, associate with the extent of radiographic joint damage. METHODS: Antibodies recognising six citrullinated epitopes were determined in sera of 330 ACPA-positive RA patients genotyped for SE alleles. The association between SE alleles, ACPA fine specificity and radiographic joint damage was assessed using radiographic follow-up data. A second cohort of 154 RA patients with 5 and 10-year radiographic follow-up was used for replication. RESULTS: SE alleles predisposed to the recognition of certain citrullinated epitopes. However, none of the ACPA fine specificities studied influenced radiographic joint damage. Importantly, although SE alleles associated with radiographic damage in the total RA population, this association was no longer detectable after stratification for the presence of ACPA. CONCLUSIONS: SE alleles are instrumental in shaping the ACPA repertoire. However, ACPA fine specificities formed under the influence of SE alleles do not seem to affect joint destruction.

Biomarkers in early rheumatoid arthritis: longitudinal associations with inflammation and joint destruction measured by magnetic resonance imaging and conventional radiographs.

OBJECTIVE: To examine associations between a panel of soluble biomarkers and progressive joint destruction assessed by magnetic resonance imaging (MRI) and conventional radiographs as well as longitudinal associations with disease activity assessed clinically and by MRI in early rheumatoid arthritis (RA) patients. METHODS: 84 early RA patients were evaluated at baseline, 3, 6 and 12 months with clinical examination, serum and urine sampling, MRI scans of the dominant wrist and conventional radiographs of the hands. A panel of biomarkers (sCTX-I, uCTX-II, sOPG, sYKL-40, sCOMP and sMMP-3) was assessed by ELISA. MRI images and conventional radiographs were scored according to the RA MRI score (RAMRIS) and the van der Heijde modified Sharp score (SHS), respectively. Longitudinal associations between biomarkers and MRI inflammation and disease activity score (DAS28) and association with the progression of damage were examined with adjustments for known predictors. RESULTS: The baseline sCTX-I level predicted progression in joint destruction assessed by MRI and conventional radiographs, whereas the uCTX-II level was a predictor of progression in SHS but not RAMRIS. Consistent associations, both with MRI inflammation (synovitis and bone marrow oedema) and DAS28 were found for sYKL-40 and sMMP-3 in addition to C-reactive protein at baseline and in longitudinal analyses. Associations remained significant in multivariate analyses. CONCLUSION: Levels of sCTX-I and uCTX-II were significant predictors of progressive joint destruction, whereas sMMP-3 and sYKL-40 were merely markers of joint inflammation. The clinical value of these markers for use in individual patients is limited due to a considerable overlap in levels of patients with progression and no progression.

The ACPA isotype profile reflects long-term radiographic progression in rheumatoid arthritis.

BACKGROUND: The presence of anti-citrullinated protein antibodies (ACPA) is a powerful predictive factor for the development and progression of rheumatoid arthritis (RA). The ACPA response has been shown to consist of various isotypes, but the consequences of differences in isotype distribution have not been extensively investigated. OBJECTIVE: To investigate the relationship between ACPA isotypes, disease progression and radiological outcome. METHODS: ACPA isotypes were determined in sera of anti-cyclic citrullinated peptide 2-positive patients by enzyme-linked immunosorbent assay (ELISA). To investigate whether the ACPA response continues to evolve during disease development, the ACPA isotype profile during progression of undifferentiated arthritis (UA) to RA was studied. The association of disease progression with ACPA isotype use was assessed using long-term radiographic follow-up data from patients with RA in two independent cohorts. RESULTS: The ACPA isotype distribution did not expand during disease progression from UA to RA, but was relatively stable over time. In both RA cohorts, the baseline ACPA isotype profile was a significant predictor of disease severity, with more isotypes indicating a higher risk of radiographic damage (odds ratio for every additional isotype: 1.4 (95% CI 1.1 to 1.9) p<0.001). ACPA isotypes supplied additional prognostic information to ACPA status alone, even after correction for other predictive factors. CONCLUSIONS: The magnitude of the ACPA isotype profile at baseline reflects the risk of future radiographic damage. These results indicate that the presence and the constitution of the ACPA response are relevant to the disease course of RA.

Therapeutic drug monitoring of infliximab compared to standard clinical treatment with infliximab: study protocol for a randomised, controlled, open, parallel-group, phase IV study (the NOR-DRUM study).

BACKGROUND: Infliximab (INX) and other tumour necrosis factor inhibitors (TNFi) have revolutionised the treatment of several immune mediated inflammatory diseases. Still, many patients do not respond sufficiently to therapy or lose efficacy over time. The large interindividual variation in serum drug concentrations on standard doses and the development of anti-drug antibodies are thought to be major reasons for treatment failures. Therapeutic drug monitoring (TDM), an individualised treatment strategy based on systematic assessments of serum drug concentrations, has been proposed as a clinical tool to optimise efficacy of INX treatment. TDM seems reasonable both from a clinical and an economical point of view, but the effectiveness of this treatment strategy has not yet been demonstrated in randomised clinical trials. The NORwegian DRUg Monitoring study (NOR-DRUM) aims to assess the effectiveness of TDM, both with regard to the achievement of remission in patients starting INX treatment (part A) as well as to maintain disease control in patients on INX treatment (part B). METHODS: The NOR-DRUM study is a randomised, open, controlled, parallel-group, comparative, multi-centre, national, superiority, phase IV study with two separate parts, NOR-DRUM A and NOR-DRUM B. Patients with rheumatoid arthritis, psoriatic arthritis, spondyloarthritis, ulcerative colitis, Crohn's disease and psoriasis are included. In both study parts participants are randomised 1:1 to either TDM of infliximab (intervention group) or to standard treatment with infliximab without knowledge of drug levels or ADAb status (control group). NOR-DRUM A will include 400 patients starting INX therapy. The primary outcome is remission at 30 weeks. In NOR-DRUM B, 450 patients on maintenance treatment with INX will be included. The primary endpoint is occurrence of disease worsening during the 52-week study period. DISCUSSION: As the first trial to assess the effectiveness, safety and cost-effectiveness of TDM in patients receiving TNFi for a range of immune mediated inflammatory diseases, we hope that the NOR-DRUM study will contribute to the advancement of evidence based personalised treatment with biological medicines. TRIAL REGISTRATION: Clinicaltrials.gov, NCT03074656. Registered on 090317.

FCRL3 -169C/C genotype is associated with anti-citrullinated protein antibody-positive rheumatoid arthritis and with radiographic progression.

OBJECTIVE: Studies of Caucasian populations have shown conflicting results concerning the association between a promoter polymorphism -169T>C of the Fc receptor-like 3 (FCRL3) gene and rheumatoid arthritis (RA). It is unknown whether FCRL3 is associated with autoantibody status and disease severity. We investigated associations between FCRL3 -169T>C and autoantibody status and joint damage in patients with RA. METHODS: A total of 652 Norwegian patients with RA from 2 cohorts and 981 Norwegian controls, previously genotyped for FCRL3 -169T>C (rs7528684), were studied. Data on anticitrullinated protein antibodies (ACPA) and rheumatoid factor (RF) were available. The EURIDISS cohort (disease duration ≤ 4 yrs at baseline) was followed longitudinally, with assessment of radiographic hand damage at baseline and after 10 years (n = 117) according to the van der Heijde-modified Sharp score. RESULTS: We found significant associations with ACPA-positive RA for both the C allele (OR 1.28, 95% CI 1.08-1.52, p = 0.004) and the C/C genotype (OR 1.57, 95% CI 1.18-2.10, p = 0.002). Similar associations were seen with RF-positive RA. No association was found with ACPA-negative or RF-negative RA. The C/C genotype was found to be associated with 10-year radiographic progression in multivariate linear and logistic regression analyses, after adjustment for ACPA, erythrocyte sedimentation rate, age, and sex. CONCLUSION: The promoter polymorphism of FCRL3 was associated with autoantibody-positive RA. Despite the low number of patients, the C/C genotype of the FCRL3 polymorphism consistently and independently predicted radiographic progression. These findings suggest that FCRL3 is involved in both disease susceptibility and progression.

Antibodies to cyclic citrullinated protein and erythrocyte sedimentation rate predict hand bone loss in patients with rheumatoid arthritis of short duration: a longitudinal study.

INTRODUCTION: Radiographic progression in rheumatoid arthritis (RA) has in several studies been shown to be predicted by serological markers widely used in daily clinical practice. The objective of this longitudinal study was to examine if these serological markers also predict hand bone mineral density (BMD) loss in patients with RA of short disease duration. METHODS: 163 patients with RA of short disease duration (2.4 years) were included and followed longitudinally. Antibodies to cyclic citrullinated protein (anti-CCP), rheumatoid factor (RF), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) were analysed from baseline blood-samples. Hand BMD was measured by digital X-ray radiogrammetry (DXR) based on hand and wrist radiographs obtained at baseline and 1, 2 and 5-year follow-up. RESULTS: During the study period, DXR-BMD decreased by median (inter quartile range) 1.7% (4.1 to 0.4), 2.8% (5.3 to 0.9) and 5.6% (11.7 to 2.3) after 1, 2 and 5 years, respectively. Elevated baseline anti-CCP, RF, ESR and CRP levels were in univariate linear regression analyses consistently associated with DXR-BMD change at all time-points. Anti-CCP and ESR were independently associated with hand DXR-BMD in multivariate linear regression analyses. Elevated anti-CCP levels were consistent and independent predictors of loss in cortical hand bone during the study period, with the odds ratios (95% confidence interval) 2.2 (1.0 to 4.5), 2.6 (1.1 to 6.2) and 4.9 (1.4 to 16.7) for the 1, 2, and 5-year follow-up periods, respectively. CONCLUSIONS: Anti-CCP and ESR were found to be independent predictors of early localised BMD loss. This finding adds to the understanding of anti-CCP and ESR as important predictors of bone involvement in RA.

Cartilage and bone biomarkers in rheumatoid arthritis: prediction of 10-year radiographic progression.

OBJECTIVE: As current predictors of joint destruction have low specificity, serological biomarkers reflecting bone and cartilage destruction have been proposed as tools in assessing prognosis of rheumatoid arthritis (RA). We examined whether serum concentrations of a panel of biomarkers could predict radiographic progression in patients with RA. METHODS: A cohort of 238 patients with RA was followed longitudinally for 10 years with collection of clinical data and serum samples. These analyses focus on the 136 patients with radiographs of the hands available at baseline and at 5 and/or 10 years. Radiographs were scored according to the van der Heijde-modified Sharp score (SHS). Baseline sera were analyzed for receptor activator of nuclear factor-kappaB ligand (RANKL), osteoprotegerin (OPG), human cartilage glycoprotein-39 (YKL-40), C2C, collagen cross-linked C-telopeptide (CTX-I), and cartilage oligomeric matrix protein (COMP). Multivariate linear and logistic regression analyses were used to identify predictors of radiographic progression. RESULTS: Baseline CTX-I levels were higher in progressors [0.41 ng/ml (interquartile range 0.31-0.75)] than in nonprogressors [0.32 ng/ml (IQR 0.21-0.49)], and were independently associated with 10-year change in radiographic damage score [ss = 16.4 (IQR 5.7-27.1)]. We found no association between radiographic progression and baseline serum levels of RANKL, OPG, C2C, YKL-40, or COMP. CONCLUSION: This longterm followup study of patients with RA indicates a relationship between elevated CTX-I levels in serum and subsequent joint destruction. This association was, however, weak, and our study does not support that serum CTX-I or any of the other tested biomarkers will serve as more useful prognostic markers than current predictors such as anti-cyclic citrullinated peptide, radiographic damage early in the disease course, and signs of inflammation.

Testing of the OMERACT 8 draft validation criteria for a soluble biomarker reflecting structural damage in rheumatoid arthritis: a systematic literature search on 5 candidate biomarkers.

OBJECTIVE: To test the OMERACT 8 draft validation criteria for soluble biomarkers by assessing the strength of literature evidence in support of 5 candidate biomarkers. METHODS: A systematic literature search was conducted on the 5 soluble biomarkers RANKL, osteoprotegerin (OPG), matrix metalloprotease (MMP-3), urine C-telopeptide of types I and II collagen (U-CTX-I and U CTX-II), focusing on the 14 OMERACT 8 criteria. Two electronic voting exercises were conducted to address: (1) strength of evidence for each biomarker as reflecting structural damage according to each individual criterion and the importance of each individual criterion; (2) overall strength of evidence in support of each of the 5 candidate biomarkers as reflecting structural damage endpoints in rheumatoid arthritis (RA) and identification of omissions to the criteria set. RESULTS: The search identified 111 articles. The strength of evidence in support of these biomarkers reflecting structural damage was low for all biomarkers and was rated highest for U-CTX-II [score of 6.5 (numerical rating scale 0-10)]. The lowest scores for retention of specific criteria in the draft set went to criteria that refer to the importance of animal studies, correlations with other biomarkers reflecting damage, and an understanding of the metabolism of the biomarker. CONCLUSION: Evidence in support of any of the 5 tested biomarkers (MMP-3, CTX-I, CTX-II, OPG, RANKL) was inadequate to allow their substitution for radiographic endpoints in RA. Three of the criteria in the draft criteria set might not be required, but few omissions were identified.

Reappraisal of OMERACT 8 draft validation criteria for a soluble biomarker reflecting structural damage endpoints in rheumatoid arthritis, psoriatic arthritis, and spondyloarthritis: the OMERACT 9 v2 criteria.

OBJECTIVES: A draft set of criteria for the validation of soluble biomarkers reflecting damage endpoints was proposed at OMERACT 8. At OMERACT 9 we aimed to scrutinize the necessity for each of these criteria according to the objectives of the working group. METHODS: The OMERACT 8 draft criteria and the principle objectives of the validation process were clarified at a meeting of the working group in London, December 2007. A new framework was proposed after the following steps were conducted: (A) A systematic review of the literature focusing on the draft criteria and a preselected group of biomarkers (MMP3, CTX-II, RANKL, OPG, CTX-I) followed by a Delphi consensus exercise addressing the importance of individual criteria and identification of omissions in the draft set. (B) Formal debate as well as group discussion centered on the key arguments for inclusion/exclusion of specific criteria. (C) Onsite interactive electronic voting on the importance of specific criteria. The framework was presented and discussed at OMERACT 9 in both breakout and plenary sessions followed by a vote on its acceptance. RESULTS: The objectives of rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis biomarkers in relation to their predictive validity for damage endpoints was clarified and supported by OMERACT 9 participants. The OMERACT 8 draft validation criteria were reformulated into an essential category focused on criteria addressing the OMERACT Filter elements of discrimination (incorporating truth) and feasibility, and a desirable but nonessential category of other criteria addressing truth. This revised draft set was endorsed by participants at OMERACT 9. CONCLUSION: A revised set of validation criteria has been drafted by consensus at OMERACT 9 that focuses on the performance characteristics of biomarker assays, the importance of addressing potential confounders, and the essential requirement for clinical validation studies.

Proposal for levels of evidence schema for validation of a soluble biomarker reflecting damage endpoints in rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis, and recommendations for study design.

OBJECTIVE: At OMERACT 8 a framework for levels of evidence was proposed for the validation of biomarkers as surrogate outcome measures. We aimed to adapt this scheme in order to apply it in the setting of soluble biomarkers proposed to replace the measurement of damage endpoints in rheumatoid arthritis (RA), psoriatic arthritis (PsA), and ankylosing spondylitis (AS). We also aimed to generate consensus on minimum standards for the design of longitudinal studies aimed at validating biomarkers. METHODS: Before the meeting, the Soluble Biomarker Working Group prepared a preliminary framework and discussed various models for association and prediction related to the statistical strength domain. In addition, 3 Delphi exercises addressing longitudinal study design for RA, PsA, and AS were conducted within the working group and members of the Assessments in SpondyloArthritis International Society (ASAS) and the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA). This formed the basis for discussions among OMERACT 9 participants. RESULTS: The proposed framework was accepted by consensus. In the study design domain a requirement for both prospective observational studies and randomized controlled trials (RCT) in different drug classes was noted. A template for determining the level of statistical strength was proposed. The addition of a new domain on biomarker assay performance was considered essential, and participants suggested that for any biomarker this domain should be addressed first, i.e., before starting clinical validation studies. Participants agreed on most elements of a longitudinal study design template. Where consensus was lacking the working group has drafted solutions that constitute a basis for prospective validation studies. CONCLUSION: The OMERACT 9 Soluble Biomarker Group has successfully formulated a levels of evidence scheme and a study design template that will provide guidance to conduct validation studies in the setting of soluble biomarkers proposed to replace the measurement of damage endpoints in RA, PsA, and AS.

A high serum level of eotaxin (CCL 11) is associated with less radiographic progression in early rheumatoid arthritis patients.

INTRODUCTION: Prognosis in rheumatoid arthritis (RA) is difficult to assess. The aim of this study was to examine whether serum levels of a spectrum of cytokines were predictive of radiographic progression in early RA patients. METHODS: A total of 82 early RA patients (disease duration < 1 year) were followed for 12 months. Clinical assessments, X-rays of hands and magnetic resonance imaging (MRI) of the dominant wrist were assessed at baseline and after 3, 6 and 12 months. The X-rays were scored according to the van der Heijde modified Sharp score (vdHSS). Cytokine analyses were performed with multiplex technology. Associations between cytokines and radiographic progression were examined by logistic regression. RESULTS: In all, 49% of the patients developed radiographic progression. The median (interquartile range (IQR)) baseline eotaxin level (pg/ml) was significantly lower in patients with (193 (119 to 247)) than without progression (265 (166 to 360)). In the univariate logistic regression analyses, eotaxin was negatively associated to radiographic progression, and this association was maintained in the multivariate model with an odds ratio (OR) (95% confidence interval (CI)) for progression of 0.58 (0.41 to 0.82) per 50 pg/ml increase in eotaxin level. None of the other measured cytokines showed any association to radiographic progression. CONCLUSION: This study raises the hypothesis that high serum levels of eotaxin predict less radiographic progression in early RA patients.

Testing of the preliminary OMERACT validation criteria for a biomarker to be regarded as reflecting structural damage endpoints in rheumatoid arthritis clinical trials: the example of C-reactive protein.

OBJECTIVE: A list of 14 criteria for guiding the validation of a soluble biomarker as reflecting structural damage endpoints in rheumatoid arthritis (RA) clinical trials was drafted by an international working group after a Delphi consensus exercise. C-reactive protein (CRP), a soluble biomarker extensively studied in RA, was then used to test these criteria. Our objectives were: (1) To assess the strength of evidence in support of CRP as a soluble biomarker reflecting structural damage in RA according to the draft validation criteria. (2) To assess the strength of recommendation for inclusion of individual criteria in the draft set. METHODS: A systematic literature review was conducted to elicit evidence in support of each specific criterion composing the 14-criteria draft set. A summary of the key literature findings per criterion was presented to both the working group and to participants in a special interest soluble biomarker group at OMERACT 8. Participants at OMERACT 8 were asked to rate the strength of evidence and the strength of the recommendation in support of each individual criterion on a 0-10 numerical rating scale. Working group members not present at OMERACT voted by a Web-based survey. RESULTS: Minimal data were extracted from the literature pertaining to those criteria listed under the category of truth. Ratings for strength of evidence were moderate to low (< 7) for CRP as a biomarker reflecting structural damage in RA; this was true for all criteria except those listed under the category of feasibility and 2 listed under the category of discrimination pertaining to assay reproducibility and evidence regarding sources of variability. Ratings for strength of recommendation for inclusion of each of the 14 criteria in the draft set were high (> 7) except for those criteria listed under the category of truth. CONCLUSION: The draft criteria serve as a useful template in the evaluation of the strength of evidence in support of a particular soluble biomarker as reflecting structural damage in RA.