A W R van Kuijk

Detailed analysis of the cell infiltrate and the expression of mediators of synovial inflammation and joint destruction in the synovium of patients with psoriatic arthritis: implications for treatment

Background: The synovial tissue is a primary target of many inflammatory arthropathies, including psoriatic arthritis (PsA). Identification of proinflammatory molecules in the synovium may help to identify potentially therapeutic targets. Objective: To investigate extensively the features of cell infiltration and expression of mediators of inflammation and joint destruction in the synovium of patients with PsA compared with patients with rheumatoid arthritis matched for disease duration and use of drugs. Methods: Multiple synovial tissue biopsy specimens were obtained by arthroscopy from an inflamed joint in 19 patients with PsA (eight oligoarthritis, 11 polyarthritis) and 24 patients with rheumatoid arthritis. Biopsy specimens were analysed by immunohistochemistry to detect T cells, plasma cells, fibroblast-like synoviocytes, macrophages, proinflammatory cytokines, matrix metalloproteinases and tissue inhibitor metalloproteinase-1, adhesion molecules and vascular markers. Stained sections were evaluated by digital image analysis. Results: The synovial infiltrate of patients with PsA and rheumatoid arthritis was comparable with regard to numbers of fibroblast-like synoviocytes and macrophages. T cell numbers were considerably lower in the synovium of patients with PsA. The number of plasma cells also tended to be lower in PsA. The expression of tumour necrosis factor alpha (TNFα), interleukin (IL) 1β, IL6 and IL18 was as high in PsA as in rheumatoid arthritis. The expression of matrix metalloproteinases, adhesion molecules and vascular markers was comparable for PsA and rheumatoid arthritis. Conclusion: These data show increased proinflammatory cytokine expression in PsA synovium, comparable to results obtained for rheumatoid arthritis, and support the notion that, in addition to TNFα blockade, there may be a rationale for treatments directed at IL1β, IL6 and IL18.

A prospective, randomised, placebo-controlled study to identify biomarkers associated with active treatment in psoriatic arthritis: effects of adalimumab treatment on synovial tissue

Objective: To determine which of the changes in synovial tissue correlates best with clinical response associated with effective therapy (adalimumab) to facilitate the planning of future studies with therapeutic agents for psoriatic arthritis (PsA). Methods: A total of 24 patients with active PsA were randomised to receive adalimumab (n = 12) or placebo (n = 12) for 4 weeks. Synovial biopsies were obtained before and after 4 weeks of treatment. Immunohistochemical analysis was performed to characterise the cell infiltrate, expression of cytokines and matrix metalloproteinases (MMPs) and vascularity. Sections were analysed by digital image analysis. Statistical analysis was performed using covariance analysis. Results: The mean Disease Activity Score in 28 joints (DAS28) after 4 weeks was 1.92 units lower (95% confidence interval (CI) 1.07 to 2.77) after adalimumab therapy compared with placebo. Paired pretreatment and post-treatment synovial samples were available from 19 patients. Many cell types were reduced after adalimumab treatment compared to placebo. After applying a ranked analysis of covariance (ANCOVA) model to correct for baseline imbalances, a significant effect of treatment was observed on CD3-positive cells: there was a median reduction of 248 cells/mm2 after adalimumab versus placebo treatment (p = 0.035). In addition, the expression of MMP13 was significantly reduced after active treatment: the integrated optical density (IOD)/mm2 was 18 190 lower after adalimumab treatment as compared to placebo (p = 0.033). Conclusion: Adalimumab therapy in PsA is associated with a marked reduction in T cell infiltration and MMP13 expression in synovial tissue, suggesting that these parameters could be used as biomarkers that are sensitive to change after active treatment in small proof of concept studies in PsA.

TWEAK and its receptor Fn14 in the synovium of patients with rheumatoid arthritis compared to psoriatic arthritis and its response to tumour necrosis factor blockade

Objective: To investigate the expression of tumour necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK) and its receptor fibroblast growth factor inducible 14 (Fn14) in the inflamed synovium of patients with arthritis, as TWEAK blockade has been observed to have a beneficial effect in an animal model of rheumatoid arthritis (RA). Methods: Synovial tissue (ST) biopsies were obtained from 6 early, methotrexate-naive patients with RA as well as 13 patients with RA and 16 patients with psoriatic arthritis (PsA) who were matched for treatment and disease duration. Serial ST samples were obtained from a separate cohort of 13 patients with RA before and after infliximab treatment. TWEAK and Fn14 expression was evaluated by immunohistochemistry and digital image analysis. Results: TWEAK and Fn14 were clearly expressed in ST of patients with RA and PsA. TWEAK expression was significantly higher in RA (sub)lining samples compared to PsA (p = 0.005 and p = 0.014, respectively), but Fn14 expression was comparable. Double immunofluorescence showed TWEAK and Fn14 expression on fibroblast-like synoviocytes and macrophages, but not T cells. Of interest, persistent TWEAK and Fn14 expression was found after anti-TNF therapy. Conclusions: TWEAK and Fn14 are abundantly expressed in the inflamed synovium of patients with RA and PsA. This raises the possibility that blocking TWEAK/Fn14 signalling could be of therapeutic benefit in inflammatory arthritis.

SAT0391 A Diminished Clinical Response at 28 and 52 Weeks of Adalimumab Treatment in Patients with Psoriatic Arthritis is Associated with Anti-Drug Antibodies

Background Immunogenicity, the formation of anti-drug antibodies (ADA), has important clinical implications for the treatment with adalimumab of patients with rheumatic diseases, since ADA are associated with lower effective drug levels, resulting in an absent or diminished response in some patients. In contrast to rheumatoid arthritis research on immunogenicity and clinical response in patients with psoriatic arthritis (PsA) is scarce. Objectives To investigate the relationship between ADA, adalimumab drug levels and clinical response in a large, long-term follow-up cohort of patients with PsA during 52 weeks of follow-up. Methods This prospective cohort study included 103 consecutive patients diagnosed with PsA and treated with 40 mg adalimumab subcutaneously every other week. Disease activity score in 28 joints (DAS28), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and psoriasis area and severity index (PASI) were assessed at baseline and after 4, 16, 28, 40 and 52 weeks of treatment. Adalimumab concentrations and ADA were measured in serum trough samples, using an enzyme linked immunosorbent assay (ELISA) and a radio immunoassay (RIA), respectively. Results After 52 weeks of treatment, 23 (22%) patients had detectable ADA. Serum adalimumab concentrations were significantly lower at 28 and 52 weeks in patients with detectable ADA compared to patients without detectable ADA (at week 28: 1.3 mg/L [IQR 0.0-3.2] vs 8.7 mg/L [IQR 5.7-11.5], p<0.0001; at week 52: 0.9 mg/L [IQR 0.0-2.9] vs 9.4 mg/L [IQR 5.7-12.1], p=0.0001). DAS28 at 28 weeks (2.16 vs 2.95, p=0.023) and 52 weeks (2.19 vs 2.95, p=0.024) showed a significant difference; patients with detectable ADA had a poorer clinical outcome than patients without (see Table 1). Conclusions ADA was detected in 22% of the adalimumab treated PsA patients during 52 weeks of follow-up. These patients had lower adalimumab serum concentrations and a significantly poorer clinical outcome for DAS28 and CRP at week 28 and 52 compared to patients in whom ADA were not detected. Disclosure of Interest E. Vogelzang: None declared, E. Kneepkens: None declared, M. Nurmohamed: None declared, A. van Kuijk: None declared, T. Rispens Speakers bureau: Pfizer and Abbvie, G. Wolbink Grant/research support: Pfizer, Speakers bureau: Pfizer and Amgen, C. Krieckaert Speakers bureau: Pfizer and Abbvie DOI 10.1136/annrheumdis-2014-eular.2162

OP0074 A Concentration-Effect Curve of Adalimumab in Patients with Psoriatic Arthritis

Background In rheumatoid arthritis the concentration-effect relationship of adalimumab has been investigated.[1] However, in psoriatic arthritis (PsA) there is a lack of knowledge about the pharmacodynamics and pharmacokinetics of adalimumab. Objectives To investigate the relationship between serum adalimumab trough concentrations and clinical response in PsA patients after 28 weeks of treatment, using a concentration-effect curve. Methods In this prospective cohort study 103 consecutive patients diagnosed with PsA were included and treated with 40 mg adalimumab subcutaneously every other week. Adalimumab concentrations at 28 weeks of treatment were measured in serum trough samples, using an enzyme linked immunosorbent assay (ELISA). Clinical response was defined as a change in disease activity score in 28 joints (ΔDAS28) between baseline and week 28. All patients were sorted from low to high adalimumab concentration (mg/L). Each dot represents 10 patients (the last dot represents 13 patients) and their mean adalimumab trough concentration and mean ΔDAS28. Results At 28 weeks of treatment serum trough concentrations ranged from 0.0 to 18.8 mg/L, with a mean of 7.2 mg/L. Concentrations of approximately 1.0 mg/L already showed reasonable efficacy. Adalimumab concentrations of 5-8 mg/L appear most optimal. (see figure 1) Concentrations above 8 mg/L appear to have no additional benefit. In 48 (47%) patients adalimumab concentrations exceeded 8 mg/L. Furthermore 36 (35%) patients had adalimumab concentration below 5 mg/L. Conclusions Adalimumab concentrations of 5-8 mg/L appear necessary for achieving the most optimal clinical benefit. A substantial group of PsA patients that uses adalimumab are not able to profit from this optimal clinical benefit. This study, in patients with PsA, confirms the results that have been found in RA patients. References Pouw MF et al. Key findings towards optimising adalimumab treatment: the concentration-effect curve. Ann Rheum Dis. 2013 [Epub ahead of print]. Disclosure of Interest E. Vogelzang: None declared, E. Kneepkens: None declared, M. Nurmohamed: None declared, A. van Kuijk: None declared, T. Rispens Speakers bureau: Pfizer and Abbvie, G. Wolbink Grant/research support: Pfizer, Speakers bureau: Pfizer and Amgen, C. Krieckaert Speakers bureau: Pfizer and Abbvie DOI 10.1136/annrheumdis-2014-eular.1863

Synovial synoviolin in relation to response to TNF blockade in patients with rheumatoid arthritis and psoriatic arthritis

Recently, synoviolin, a novel E3 ubiquitin ligase, was identified in rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLS) and synovial tissue, where it may contribute to the dysregulated proliferation and apoptosis seen in RA.1 2 Synoviolin expression is also associated with arthritis development in mice.1 The exact mechanism of synoviolin regulation and expression remains to be elucidated, but recently a role for tumour necrosis factor α (TNFα) and interleukin 1b was suggested as these cytokines increased the expression of synoviolin in RA FLS.3 Another interesting observation is that high level sustained expression of synoviolin in whole peripheral blood was related to decreased clinical response in RA patients treated with TNF blockade.4 Therefore, we investigated synoviolin expression in synovium and its relationship to later response to TNF blockade in patients with RA compared with psoriatic arthritis (PsA) and osteoarthritis (OA). Synovial tissue samples were obtained …

THU0443 Unmet Needs in Psoriatic Arthritis: One Third of The Patients with Quiescent Disease According To The Rheumatologist's Opinion Do Not Achieve Minimal Disease Activity: Table 1

Background Several new drugs, including ustekinumab, apremilast, and secukinumab, became available for the treatment of psoriatic arthritis (PsA) over the last years, broadening our possibilities to treat the disease effectively. The new therapeutic modalities open a new perspective for patients not responding to conventional DMARDs and TNF inhibitors (TNFi). As achieving the lowest possible level of disease activity in all domains of disease is associated with better long-term outcomes, the new therapeutic modalities may potentially also benefit patients with partial but not full disease control with cDMARDs and/or TNFi.1 Therefore, defining an acceptable disease state in routine clinical practice is becoming increasingly important to identify who could potentially benefit from treatment adjustment. Objectives The aim of the study was to assess how many patients with quiescent disease according to the treating rheumatologist have an acceptable disease state defined as minimal disease activity. Methods This cross-sectional study was performed in 2 rheumatology outpatient clinics and included a total of 250 PsA patients between Feb 2013 and June 2015. Key inclusion criteria were fulfillment of the CASPAR criteria and quiescent disease in the opinion of the treating rheumatologists, defined by the fact that the rheumatologist did not consider to modify the current treatment. Patients were systematically evaluated by an independent research physician for current disease activity including clinical assessments and patient reported outcomes (PRO). Minimal disease activity (MDA) was defined as the fulfillment of ≥5 of the following: TJC68≤1, SJC68≤1, PASI≤1, VASpain≤15mm, VASptglobal≤20mm, HAQ≤0.5, tender entheseal points≤1. Results One third (88/250) of the PsA patients with quiescent disease according to the treating rheumatologist did not fulfill MDA criteria (MDA-). A high TJC, VASpain and VASptglobal were the items most frequently contributing to the failure to achieve MDA (not achieved in 83%, 82% and 80%). However, also objective signs of disease activity were higher in MDA- vs MDA+ patients: a SJC>1 occurred in 35% vs 7% (p=0.000), enthesitis>1 in 14% vs 3% (p=0.002), and PASI>1 in 43% vs 26% (p=0.002). There was no difference in treatment use (including cDMARD and TNFi) between MDA- and MDA+. See table 1 for additional patient characteristics.Table 1 All pts MDA+ MDA- p-value (<0.05 = sign.) N 250 162 88 Patient characteristics mean (SD)  Age 55 (11) 53 (12) 59 (10) 0.000  Gender (%♀ ) 33% 50% 26% 0.002  Age at arthritis onset 43 (12) 41 (12) 45 (11) 0.021 PRO scores median (IQR)  HAQ 0.25 (0–0.63) 0.0 (0–0.38) 0.75 (0.5–1.38) 0.000  DLQI 1 (0–3) 0 (0–1) 2 (0–5) 0.000  SF-36 PCS 46 (39–54) 51 (46–54) 38 (31–43) 0.000  VAS pt global (mm) 10 (3–29) 6 (1–11) 37 (23–56) 0.000  WPAI (daily activities) 1 (0–4) 1 (0–2) 4 (2–7) 0.000 Laboratory median (IQR)  ESR (mm/hr) 6 (4–11) 5 (3–9) 8 (5–16) 0.000 Conclusions One third of the PsA patients with quiescent disease according to the treating rheumatologist do not achieve the MDA criteria. These patients have higher disease activity both on subjective and objective disease activity measurements. As this is associated with worse PROs, further research should evaluate if treatment adjustments may be beneficial for this patient group with residual disease activity. References L. Coates et.al, GRAPPA Treatment Recs for PsA, Arhtritis & rheumatology 2015 Disclosure of Interest L. Van Mens: None declared, A. van Kuijk Consultant for: Celgene, Janssen, MSD, Novartis, Speakers bureau: BMS, Roche, D. Baeten Grant/research support from: Pfizer, MSD, AbbVie, UCB, Novartis, Janssen, Boehringer Ingelheim, This study was supported by an unrestricted grant from Pfizer to DB, Consultant for: Pfizer, MSD, AbbVie, UCB, Novartis, Janssen, Boehringer Ingelheim, Eli Lilly, Roche, BMS, Glenmark

SAT0558 Association Between Etanercept Concentrations and Disease Activity in Psoriatic Arthritis During 52 Weeks of Follow-Up

Background In registration trials, etanercept has shown to improve clinical outcome for patients with psoriatic arthritis (PsA).[1] However a proportion of patients does not respond or lose response to the drug. In patients with rheumatoid arthritis (RA) it was observed that etanercept trough concentrations were significantly lower in EULAR moderate and non responders compared to good responders.[2] Thus far, etanercept concentrations, have not yet been investigated in PsA. Objectives To investigate the relationship between etanercept concentrations and clinical response in a prospective cohort of PsA patients starting etanercept treatment. Methods This prospective cohort study comprised 154 consecutive PsA patients with mainly peripheral joint involvement and treated with etanercept once 50 mg or twice 25 mg every week. At baseline and during follow up at 4, 16, 28, 40 and 52 weeks trough serum samples were collected and disease activity was assessed using the disease activity score using 28 joint count (DAS28), C-reactive protein (CRP) and Psoriasis Area Severity Index (PASI). Low disease activity was defined as DAS28<2.6. Etanercept trough concentrations were measured using an enzyme-linked immunosorbent assay (ELISA). Patients were categorised into tertiles based on etanercept trough concentrations at week 52 as followed: low, intermediate and high. Generalized estimating equation (GEE) and χ2 were used for statistical analysis. Results Etanercept concentration tertiles were: high concentrations >2.12 mg/L with median 2.80 mg/L (IQR 2.43-3.12), intermediate concentrations 1.35-2.12 mg/L with median 1.76 mg/L (IQR 1.58-1.92) and low concentrations <1.34 mg/L with median 0.99 mg/L (IQR 0.72-1.19). A significant difference was shown in the percentage of patients that achieved low disease activity between low and high etanercept levels; 30% vs. 38%, respectively, p=0.023 (figure 1). No significant difference in low disease activity percentages were found for intermediate vs. low and intermediate vs. high etanercept concentrations. Furthermore, using GEE, patients with higher disease activity during 52 weeks of follow-up, had significantly lower etanercept concentrations (β -0.114, 95%CI -0.204 - -0.024, p=0.013). However, no significant difference was found for CRP (β -0.365, 95%CI -0.911 - 0.181, p=0.190) or PASI (β 0.281, 95%CI -0.283 - 0.845, p=0.328). Conclusions Patients with high etanercept trough concentrations did achieve low disease activity more often compared to patients with low etanercept concentrations. For CRP and PASI no association was found. References Mease PJ, Goffe BS, Metz J, et al. Etanercept in the treatment of psoriatic arthritis and psoriasis: a randomised trial. Lancet 2000; 356:385-90. Jamnitski A, Krieckaert CL, Nurmohamed MT, et al. Patients non-responding to etanercept obtain lower etanercept concentrations compared with responding patients. Ann Rheum Dis 2012;71:88–91. Disclosure of Interest E. Vogelzang: None declared, C. Krieckaert Speakers bureau: Pfizer and Abbvie, M. Nurmohamed Consultant for: Abbott, Roche, Pfizer, MSD, UCB, SOBI and BMS, Speakers bureau: Abott, Roche and Pfizer, E. Kneepkens Speakers bureau: Pfizer, T. Rispens Speakers bureau: Pfizer and Abbvie, A. Van Kuijk: None declared, G. Wolbink Grant/research support from: Pfizer (paid to the institution), Speakers bureau: Pfizer and Amgen

SAT0246 Proteomic analysis of synovial tissue: A unique tool to predict response to anti-TNF-α therapy in patients with inflammatory arthritis

Background Inflammatory arthritis, which includes rheumatoid arthritis (RA) and psoriatic arthritis (PsA), is a leading cause of joint deformity, disability and reduced quality of life with a high economic cost [1]. A common target for therapeutic intervention is TNF-α, a key cytokine that drives the inflammatory and destructive processes of these diseases. However, due to common drug failure, diverse degree of response to therapy, cost of treatment as well as adverse drug events [2, 3] there is an urgent need for personalised medicine [4]. Objectives We hypothesized that there are distinct proteins or peptides within the synovial tissue that may predict the degree of response to anti TNF-α therapy in patients with inflammatory arthritis. Hence we aim to discover, develop and validate potential predictive biomarkers of treatment outcomes and map the protein changes to potential pathways. Methods Baseline protein expressions were investigated and compared in the synovium of 20 PsA patients with diverse responses to adalimumab (a monoclonal antibody against TNF-α) [5]. The EULAR response criteria were used to classify patients’ treatment response categories at 3 months follow-up. Synovial proteins were extracted, subjected to digestion with trypsin and the resulting peptides were analysed by label free liquid chromatography-mass spectrometry (LC-MS) on an Agilent 6520 QTOF with HPLC chip cube source attached. Progenesis LC-MS software (version 2.6) was used for the differential proteomic expression analysis. Results The protein profile of the different response categories varied. 313 proteins were differentially expressed between responders and non-responders. The majority of these proteins have been found to be associated with inflammation. The identified proteins were quantified. 68 proteins were over expressed and 64 proteins under expressed in responders. Looking at the data, a cut off p-value<0.05 and fold change>2 were used to select the biomarker panel. This resulted into 19 proteins significantly over expressed in responders and 22 proteins over expressed in non responders. Conclusions Label-free LC-MS of synovial tissue is a robust approach to the discovery of differentially expressed proteins that might predict response in PsA patients. These proteins are potential candidate synovial biomarkers of response to anti-TNF-α therapy and will be validated on a larger cohort of patients. The possibility of detecting and measuring these candidate markers in the serum will be explored. References Heuber and Robinson Proteomics Clin. Appl.6, 4100-4105(2006) Fitzgerald and Winchester. Arthritis Res. Ther., 11(1), 214(2009) Bennett et al; Rheumatology, 44(8), 1026(2005) Liao et al. Arthr& Rheum.,50(12),3792-3803(2004) van Kuijk et al. Ann Rheum Dis. 68(8), 1303-1309 (2009) Disclosure of Interest None Declared

FRI0045 Expression of IL-17A, IL-17F and their receptors in inflammatory arthritis: IL-17A expression in synovium and skin is differentially regulated by adalimumab

Background Accumulating evidence suggests an important role for interleukin (IL)-17 in the pathogenesis of several inflammatory diseases, including rheumatoid arthritis (RA), psoriatic arthritis (PsA) and psoriasis. IL-17A has been well studied in models of arthritis, but little is known about the relative expression and cellular source(s) of IL-17A, IL-17F, and their receptors in human synovial tissue and psoriatic skin. Objectives To determine the origin and expression of IL-17A, IL-17F and their receptors IL-17RA and IL-17RC in synovium and skin of patients with arthritis and their change upon anti-TNF treatment. Methods Synovial biopsies were obtained from patients with RA (n=13), PsA (n=15) and inflammatory osteoarthritis (OA, n=14). In addition, paired synovial and skin (paired lesional and non-lesional skin) samples from adalimumab treated PsA patients (n=12) were obtained before and 4 weeks after treatment. For comparison synovium (n=7) and skin (n=14) from non-inflammatory controls were included. Frozen sections were stained for IL-17A, IL-17F, IL-17RA and IL-17RC, and evaluated by digital image analysis. To determine which cells in the synovium produce IL-17A and IL-17F, double staining with CD4, CD8, CD15, CD68, CD163, CD19, CD31, Von Willebrand Factor, PNAd, Lyve-1 and tryptase was performed and evaluated by confocal microscopy. Results Levels of IL-17A, IL-17F, IL-17RA and IL-17RC were abundantly present in synovial tissues of all patient groups and highly variable between patients. Whereas IL-17RA was mostly present in the synovial sublining, IL-17RC was abundantly expressed in the intimal lining layer. Digital image analysis showed a significant increase of only IL-17A in arthritis patients compared to non-inflamed control tissues. The expression of IL-17A, IL-17F and IL-17RA was similar in the different patient groups, while expression of IL-17RC in the intimal lining layer was significantly increased in PsA compared to OA patients. CD4 and CD8 positive cells co-stained with IL-17A and to a lesser extent with IL-17F. IL-17A and IL-17F were not expressed by CD15 en CD19 positive cells. Mast cells occasionally were positive for IL-17A/IL-17F. Interestingly, IL-17A and IL-17F staining was also observed in some macrophages as well as in endothelial cells and lymphatics. Strikingly, PsA patients treated with anti-TNF showed a significant upregulation of synovial IL-17A. In both lesional and non-lesional psoriatic skin, IL-17A and IL-17RC were abundantly present in the epidermis. Anti-TNF treatment had no effect on IL-17A and IL-17RC expression in psoriatic skin. Conclusions Increased expression of IL-17A is not restricted to synovial tissues of RA and PsA patients but also observed in inflammatory OA. In inflamed synovium various cell types contribute to the production of IL-17A and IL-17F. Regulation of IL-17A by anti-TNF is dependent on the local tissue environment. Disclosure of Interest None Declared