OBJECTIVES:In our previously reported trial of intra-articular tolerogenic dendritic cells (tolDC) as a treatment to restore immune tolerance in autoimmune arthritis, high doses of cells appeared to stabilise knee symptoms, although no systemic clinical or immunomodulatory effects were observed. We therefore sought to understand how tolDC affected the local synovial immune landscape. METHODS:Synovial biopsies were taken at baseline and 14 days after intra-articular injection of tolDC or, as a control, saline washout. Histopathological analyses (Krenn evaluation and pathotype) and multiparametric imaging mass cytometry (IMC) were performed on paired synovial tissues from 7 participants (5 tolDC-treated and 2 controls), selected based on tissue availability at both time points. The IMC panel included 27 antibodies defining lymphoid, myeloid, and stromal cells. RESULTS:We observed no changes in the histopathology or the overall distribution of broadly classified cell populations (myeloid, lymphoid, and stromal) before and after tolDC administration. Furthermore, the proportions of CD4+ and CD8+ T cells were not altered, with no indication that tolDC had induced regulatory T cells within the synovium. However, we found a significant increase in a subset of myeloid cells expressing high levels of the inflammation resolution marker Mer tyrosine kinase (MerTKHigh), which positively correlated with tolDC dose. Moreover, the percentages of total MerTK+ myeloid cells inversely correlated with arthroscopic synovitis scores at both time points. CONCLUSIONS:The tolDC-induced increase in synovial Myeloid MerTKHigh cells may have local immune modulatory effects and provide promising evidence for an effect of tolDC treatment on the synovial immune landscape.

OBJECTIVE:CD4 T cells specific for citrullinated (cit) peptides are key players in rheumatoid arthritis (RA) immunopathogenesis. Characterizing these cells and identifying features of healthy and RA-associated autoreactivity will provide valuable insight into disease mechanisms and form the basis of immune state biomarkers to facilitate the next generation of RA treatments. We sought to characterize these cells in a UK early arthritis cohort. METHODS:Cit-peptide-specific (autoreactive) CD4 T cells from human leukocyte antigen (HLA)-DRB1 04:01-positive healthy controls (HCs; n = 9), patients with RA at different disease stages (n = 17 pretreatment and 13 receiving treatment), and six at-risk individuals were assessed using major histocompatibility complex II peptide tetramers combined with spectral flow cytometry. Autoreactive T cell frequency and phenotype were studied, with a particular focus on the memory CD4 T cell compartment. RESULTS:There was no statistically significant difference in autoreactive T cell frequency between comparator groups. In HCs, however, autoreactive T cells were more likely to be naive. In early pretreatment RA, autoreactive memory T cells demonstrated down-regulation of CD27 and CD28 and expression of the fractalkine receptor CX3CR1, features that have been linked to CD4 cytotoxicity. The proportion of CD27-negative autoreactive cells decreased following treatment, and RA-associated features were evident in some at-risk donors before RA onset. CONCLUSION:In RA, CD4 T cell autoreactivity is characterized by a surface phenotype that suggests in vivo activation and the potential to acquire cytotoxic capacity, whereas healthy autoreactivity demonstrates naivety. These observations suggest maturing autoreactivity in RA and may provide novel tools for monitoring disease progression and tolerance.

ISSUE ADDRESSED:The early childhood and education care (ECEC) sector has faced substantial contextual changes over the years. It is unknown whether prevalence of adoption of health promotion policies and practices has been impacted over this time. This study aimed to assess the prevalence of these policies and practices within New South Wales (NSW) ECEC services between 2013 and 2021-2022. METHODS:A repeat cross-sectional survey was undertaken in 2013 and 2021-2022 with NSW ECEC services to assess their adoption of eight evidence-based healthy eating and physical activity practices. Separate logistic regression models were used to compare the difference in prevalence of adoption at the two time points. RESULTS:In 2013, 214 (85.3% consent rate) services participated, while 512 (49.9%) services completed the 2021-2022 survey (271 receiving healthy eating version and 241 physical activity version). The majority of services (> 60%) had adopted each of the practices at both time points. There was a significant increase in prevalence of adoption for five of the eight practices, no difference for two practices, and a reduction in one practice (providing staff professional development for physical activity) between 2013 and 2021-2022. CONCLUSIONS:This study suggests that at a population level, services have maintained or increased their adoption of the majority of health promotion policies and practices over time. SO WHAT?: State-funded implementation support provided to ECECs can result in the continued delivery of health-promoting policies and practices within ECEC services to create Healthy Settings for child health promotion.

OBJECTIVE:Here we investigate the status of the adiponectin-PEPITEM pathway in early, treatment naive rheumatoid arthritis (RA) and psoriatic arthritis (PsA) and the therapeutic efficacy of PEPITEM administration in preclinical models. METHODS:Peripheral blood was isolated from patients with clinical suspect arthralgia and suspected inflammatory arthritis and analyzed by flow cytometry or Western blot. Effect of PEPITEM treatment on inflammatory arthritis was assessed in mice by histology, single-cell RNA sequencing, flow cytometry, or multiplex analysis. RESULTS:Patients newly diagnosed with RA and PsA had significantly reduced expression of adiponectin receptor 2 and its downstream signaling adapter protein APPL-1 on their peripheral-blood mononuclear cells, resulting in diminished response to adiponectin and local synovial concentrations of PEPITEM. Building on these observations, treatment with PEPITEM in three distinct inflammatory arthritis animal models significantly reduced arthritis severity, joint swelling, leukocyte infiltration, and expression of several pro-inflammatory mediators (eg, JE [CCL2], RANTES, interleukin-16) in the synovium. Mechanistically, PEPITEM treatment suppressed the cyclooxygenase 2 and NF-κB signaling pathways. Moreover, PEPITEM altered the composition of leukocyte subsets recruited into the joint. CONCLUSION:Collectively, these findings underscore the importance of understanding the dysregulation of the adiponectin-PEPITEM pathway in different immune-mediated inflammatory diseases (IMIDs), such as RA and PsA. The observed differences in expression and downstream signaling through adiponectin receptors suggest potential targets for therapeutic intervention to restore the balance of this regulatory pathway to mitigate chronic inflammation and disease progression in these patients, paving the way for its clinical use as an alternative and/or combination therapy for early IMIDs.

Objectives Drug withdrawal in rheumatoid arthritis (RA) in remission can reduce toxicity, but with the risk of flare which requires close monitoring. We explored the potential of patient-reported outcomes (PROs) for flare detection among RA patients in sustained remission after conventional synthetic disease-modifying antirheumatic drug (csDMARD) cessation.Methods Four PROs (Factors that Limit sustAined Remission in rhEumatoid arthritis (FLARE-RA), EuroQol-5 Dimensions (EQ5D), Routine Assessment of Patient Index Data-3 (RAPID-3) and RA Flare Questionnaire (RA-FQ)) were captured at baseline and at sequential visits until time-of-flare or end of 6-month follow-up as part of the BIO-FLARE prospective cohort study. Flare was defined as any of (i) Disease Activity Score 28 (DAS28)-C reactive protein (CRP) ≥3.2 at any visit, (ii) DAS28-CRP≥2.4 on two visits within 2 weeks or (iii) resuming DMARD and/or steroid therapy despite DAS28-CRP<2.4. Cox regression models with time-varying covariates were fitted to evaluate associations between PRO changes and likelihood of flare. Receiver-operating characteristic (ROC) curves enabled discriminatory changes in each PRO to be compared as a means of identifying flare.Results 58/121 (47.9%) participants (70.1% females, mean age 64.8 years) experienced a flare. A 1-point change in each PRO score was strongly associated with flare development in the multivariate Cox regression model (p<0.001 in each case). ROC curve analysis confirmed that monitoring adverse changes in PROs from baseline offered robust discriminatory utility for identifying flare occurrence. This was most evident for RA-FQ and FLARE-RA (both areas under the curves 0.90, 95% CI 0.84 to 0.96; p=0.001); for example, an RA-FQ increment of ≥5.5 from baseline identified objective flare with positive and negative predictive values of 80% and 91%, respectively.Conclusions Our data support the potential value of remote PRO monitoring of RA patients in drug-free remission to identify flare occurrence.

Tolerogenic dendritic cells (tolDC) are currently in clinical trials for the treatment of autoimmune diseases such as rheumatoid arthritis and multiple sclerosis. The methods for producing therapeutic tolDC vary widely, with little being known about the commonalities and differences of distinct cell products in terms of their regulatory actions on CD4+ T cells. We compared human monocyte-derived tolDC generated with vitamin D3 alone or in combination with dexamethasone. We found marked differences in the surface expression of HLA-DR and immune regulatory molecules, but also found commonalities, e.g. a strongly reduced capacity to produce interleukin-12 and a concomitant decreased ability to induce interferon-γ secretion by allogeneic CD4+ T cells. To gain a deeper understanding of how these tolDC types exert their regulatory effects, we co-cultured them with CD4+ T cells from rheumatoid arthritis patients or healthy controls and analysed the gene expression profile and function of the responding T cells. We found that tolDC generated with vitamin D3 alone, but not in combination with dexamethasone, induced potent cytotoxic activity in the responding CD4+ T cells as demonstrated by an enhanced cytotoxic gene signature, increased levels of intracellular granzyme B, and superior cytotoxic activity towards myeloid and B cells. These data identify cytotoxicity as an atypical CD4+ T helper cell effector function induced by some but not all tolDC types, with implications for their individual clinical applications.

BACKGROUND:Rheumatoid arthritis increases the risk of generalised muscle wasting, with chronic inflammation contributing to the loss of muscle mass and strength. Tofacitinib, a Janus kinase (JAK) inhibitor used to treat rheumatoid arthritis, increases serum creatinine concentrations without conclusive evidence of nephrotoxicity. In the Rheumatoid Arthritis and Muscle (RAMUS) study, we investigated whether tofacitinib affects muscle volume, strength, and function. METHODS:RAMUS was a prospective, single-arm, single-centre, proof of concept experimental study, done at Freeman Hospital, Newcastle upon Tyne, UK. Patients aged older than 18 years, with rheumatoid arthritis (according to the 2010 American College of Rheumatology and European Alliance of Associations for Rheumatology [ACR-EULAR] classification criteria for rheumatoid arthritis) initiating tofacitinib as standard care were recruited. Additional inclusion criteria were at least one sarcopenia risk factor, no previous treatment with JAK inhibitors, no systemic glucocorticoid treatment for at least 4 weeks before the baseline visit, and serum creatinine 1·5 times the upper limit of normal or less. Participants provided blood samples at baseline, 1 month, and 6 months; vastus lateralis biopsies were performed at baseline and 6 months. The primary outcome was change in lower limb muscle volume, assessed by quantitative MRI at baseline and after 1 and 6 months of tofacitinib treatment, and was assessed in all participants who completed the study. Secondary outcomes included changes in serum creatinine, appendicular lean mass index, muscle strength, muscle function, and disease activity (Disease Activity Score 28-C-reactive Protein [DAS28-CRP] score). Adverse events were recorded. People with lived experience with rheumatoid arthritis were involved in the design and set-up phases of this study. RAMUS was registered with ISRCTN (ISRCTN13364395). FINDINGS:Between Jan 21, 2021, and March 1, 2023, 22 patients were screened, and 15 (68%) were eligible and completed the study. 13 (87%) of 15 patients were female, two (13%) were male, 12 (80%) were White, and the mean age was 59·6 years (SD 10·0). After 6 months, tofacitinib treatment was associated with significant increases in lower limb muscle volume (mean increase 242 cm3 [95% CI 44-441], p=0·017), particularly in the thigh, and significant increases in serum creatinine (p=0·0011). Disease activity (DAS28-CRP) was significantly reduced after 1 month of tofacitinib treatment (p=0·0064) with no further changes at 6 months. No significant changes in appendicular lean mass index, muscle strength, or muscle function were observed. 28 adverse events were recorded in 13 (87%) of 15 participants; one event was classified as severe and serious, and concerned a participant being hospitalised with COVID-19 pneumonitis before commencing tofacitinib. INTERPRETATION:Tofacitinib treatment in patients with rheumatoid arthritis was associated with increased muscle volume after 6 months. The increase in serum creatinine associated with tofacitinib treatment might reflect increased muscle volume via a direct pharmacological effect on skeletal muscle or via reduced inflammation, or a combination. Larger studies are needed to verify our findings, demonstrate functional benefit, and determine whether they are unique to tofacitinib. FUNDING:Pfizer, BMA Foundation, JGW Patterson Foundation and Newcastle Hospitals Charity.

OBJECTIVES:Endogenous retroelements (EREs) stimulate type 1 interferon (IFN-I) production but have not been explored as potential interferonogenic triggers in Rheumatoid Arthritis (RA). We investigated ERE expression in early RA (eRA), a period where IFN-I is increased. METHODS:ERE expression (LTR5, LINE1, SINE) in disease modifying treatment naïve eRA whole blood and bulk synovial tissue was examined by RT-PCR and Nanostring alongside IFN-α activity. Circulating lymphocyte subsets, including B cell subsets, from eRA patients and early psoriatic arthritis (ePsA), were flow cytometrically sorted and similarly examined. Existing established RA and osteoarthritis (OA) synovial single-cell sequencing data was re-interrogated to identify repeat elements, and associations explored. RESULTS:There was significant co-expression of all ERE classes and IFNA in eRA synovial tissue (n=22, p<0.0001) and significant positive associations between whole blood LINE1 expression (n=56) and circulating IFN-α protein (p=0.018) and anti-CCP titres (p<0.0001). ERE expression was highest in circulating eRA B-cells, particularly naïve B-cells compared with ePsA, with possible ERE regulation by SAMDH1 implicated and associations with IFNA again observed. Finally, in established RA synovium, LTRs, particularly ERVK, were most increased in RA compared with OA where, for all synovial subsets (monocytes, B-cells, T-cells and fibroblasts), ERE expression associated with increased IFN-I signalling (p<0.001). CONCLUSIONS:Peripheral blood and synovial ERE expression is examined for the first time in eRA highlighting both a potential causal relationship between ERE and IFN-I production and an intriguing association with anti-CCP autoantibodies. This suggests EREs may contribute to RA pathophysiology with implications for future novel therapeutic strategies.

Background: Seropositive RA is characterised by autoantibodies to citrullinated self-antigens (cit-peptides). CD4 T-cells are presumed key to the immunopathology given a strong HLA class II association and efficacy of co-stimulation blockade[1]. Measuring CD4 T-cells specific to disease relevant autoantigens will be vital to understand the immune dysregulation underpinning RA and in the assessment of novel, antigen specific therapies that aim to restore immune tolerance[2]. Objectives: We sought to characterise cit-peptide specific CD4 T-cells from RA patients at diagnosis and during follow up; individuals with ACPA positive arthralgia (APA) and healthy controls (HC); aiming to identify features of 'healthy' and 'pathologic' autoreactivity that could function as biomarkers in early phase trials of tolerogenic therapies. Methods: HLA DRB1 0401 positive RA and APA donors were recruited from the Newcastle Early Arthritis Clinic, HC samples were obtained from LRS cones. Antigen specific T-cells were analysed by staining cryopreserved PBMC with HLA class II tetramers containing epitopes from the candidate autoantigens citrullinated tenascin and citrullinated cartilage intermediate layer protein. To assess cell phenotype, samples were stained with surface antibodies and analysed by spectral cytometry. Results: 8 HCs, 16 RA-diagnosis, 13 RA-follow up and 5 APA samples were analysed. Overall, the frequency of antigen specific T-cells did not differ between groups. Amongst the cit-peptide specific T-cell compartment, RA-diagnosis donors had a significantly lower proportion of naïve cells (CCR7+CD45RA+) compared to HCs (28% vs 44%, p=0.017). There was a non-specific trend towards increased antigen specific effector memory and TEMRA cells amongst the RA-diagnosis group. Amongst RA-follow up and APA donors, the proportion of naïve cells was similar to HCs (47% and 38%, respectively). In paired analysis (n=7), the proportion of antigen specific naïve cells increased during follow up (20% to 47%, p=0.047). These discrepancies were not a result of differences in global T-cell population, no significant differences were observed when all CD4 T-cells were analysed. Amongst the cit-peptide specific memory compartment (CD45RA-CD45RO+), surface phenotype was compared between groups. No significant differences were observed between major T-helper subsets (Th1, Th2, Th17 and Tfh). Interestingly, Tregs (CD25+CD127-) were more common amongst HCs compared to RA-diagnosis donors (20% vs 9%, p=0.025), the frequency was slightly higher in the follow up samples (12%) and similar to HCs for APA donors (21%). RA-diagnosis donors had a significantly higher proportion of CD27- antigen specific memory CD4 T-cells compared to HCs (23% vs 9%, p=0.05), with lower levels observed in the RA-follow up and APA donors (13% and 11%, respectively). Again, these differences were not simply a reflection of the global T-cell population. Conclusion: CD4 T-cells specific for cit-peptides amongst RA-diagnosis donors were less likely to be naïve or regulatory and more likely to have down regulated CD27, in keeping with an antigen experienced effector phenotype. The RA-follow up and APA groups appeared more similar to HCs, though Tregs were still relatively low in the former group, suggesting immune dysregulation is not completely reversed by current treatments. These observations suggest persistent activation and a relative loss of antigen specific Tregs are features of pathologic autoreactivity and could be leveraged as biomarkers in trials of novel tolerogenic therapies. REFERENCES: [1] McInnes, I. B. & Schett, G. The Pathogenesis of Rheumatoid Arthritis. N. Engl. J. Med.365, 2205–2219 (2011). [2] Stanway, J. A. & Isaacs, J. D. Tolerance-inducing medicines in autoimmunity: rheumatology and beyond. Lancet Rheumatol.2, e565–e575 (2020). Acknowledgements: NIL. Disclosure of Interests: James Stanway GSK/EMINENT clinical fellowship, Amy E Anderson: None declared, Arthur Pratt EMINENT/GSK grant, John Isaacs GSK EMINENT funding.

This review assessed the effectiveness of ECEC-based interventions to improve child physical activity, and intervention impact on child weight-based anthropometrics, fundamental movement skills (FMS), cognitive functioning, and social-emotional wellbeing. Adverse effects and costs were assessed. Finch et al's 2014 systematic review was updated. Electronic databases were searched 10 September 2014 to 27 October 2022. Included studies were randomized controlled trials of ECEC interventions targeting physical activity among children aged 0-6 years. The methodological quality of studies was assessed using Cochrane's Risk of Bias tool v2. Standardized mean differences (SMD) were calculated for each outcome with meta-analysis undertaken; otherwise, findings were described narratively. Fifty-three studies were included. ECEC-based interventions were found to significantly improve child physical activity (SMD 0.193, 95% confidence interval [CI] 0.09 to 0.3; p < 0.001) and FMS (SMD 0.544, 95% CI 0.1 to 0.98; p = 0.015), compared to control. Small positive, but non-significant, effects were found for weight-based anthropometrics, cognitive functioning, and social-emotional wellbeing. Few studies reported adverse effects (n = 10), and no studies reported formal economic analyses. While ECEC-based interventions can significantly improve child physical activity and FMS, further evidence of their impact on cognitive functioning, social-emotional wellbeing, and the cost-effectiveness of such interventions is required to inform policy and practice.

Objectives Long-term outcomes in rheumatoid arthritis (RA) depend on early and effective disease control. Methotrexate (MTX) remains the first-line disease modifying therapy, however there are no biomarkers with which to identify those most likely to achieve remission. To address this unmet need we explored metabolic pathways involved in MTX mechanism of action within circulating CD4+T cells in a cohort of treatment naive patients with early RA.Methods Purified CD4+T cells were isolated from peripheral blood of 68 patients with early RA commencing MTX. The expression of a range of putative MTX metabolism and mechanism of action targets were explored by flow-cytometry and transcriptional analysis. From these data significant predictors of Disease Activity Score 28-C reactive protein (DAS28-CRP) remission (<2.4 at 6 months) were determined by logistic regression (clinical; flow-cytometry data) and linear modelling (gene expression data).Results Low baseline DAS28-CRP was associated with remission at 6 months (p=0.02). Expression of the ectonucleotidase CD39, involved in ATP-ADP conversion during adenosine synthesis, was higher on CD4+CD25 High regulatory T cells at baseline in those achieving remission (molecules of equivalent fluorescence 1264 vs 847; p=0.007). Expression of other adenosine signalling elements in CD4+T cells were also upregulated at baseline in patients achieving remission: AMPD1 (p<0.001), ADORA2b (p=0.039) and ADORA3 (p=0.047). When combined into a single predictive metric, a combination of these variables outperformed baseline DAS28-CRP in prediction of early remission (area under the curve 0.92 vs 0.67, p=0.001)Conclusions Adenosine signalling is important in the achievement of early remission with MTX in RA and biomarkers of adenosine activity may hold utility for the stratification of therapy in early disease.

Background: In rheumatoid arthritis (RA), achievement of drug-free remission is limited by significant likelihood of flare (~50%) following DMARD withdrawal[1]. BIO-FLARE (ISRCTN16371380) is a prospective longitudinal study involving complete DMARD cessation and offers the possibility for biomarker development for prediction of flare. Chromosome conformation signatures, based on chromatin loops and reflecting 3D genomic architecture, have shown potential as epigenomic biomarkers for prediction and prognosis, including response to methotrexate in RA[2]. Objectives: To develop a baseline peripheral blood chromosome conformation signature for classification of future flare versus remission in RA prior to DMARD cessation, and to compare performance as a predictive biomarker against i) clinical parameters alone and ii) a combined clinical and epigenomic model. Methods: 107 participants were selected from the BIO-FLARE study, in which RA patients in remission (DAS28-CRP <2.4) on conventional synthetic DMARDs stopped all therapy and were followed up for 24 weeks[3]. The primary outcome was flare occurrence. This binary outcome creates 2 natural comparator groups at baseline, namely future flare (F) versus maintenance of remission (R). Participants were split into discovery (n=12; 6F, 6R), training (n=50; 25F, 25R) and test/validation (n=45; 24F, 21R) sets. Chromosome conformation capture (3C) library prep was carried out on baseline peripheral blood mononuclear cells, and chromosome conformation compared between groups. For the discovery set, a custom microarray comprising ~106 probes (EpiSwitch Explorer, Oxford Biodynamics) was used for genome-wide screening to identify stable differentially abundant chromatin loops as candidates for inclusion in the final signature. Top ranked loops by fold change and significance were selected for translation to qPCR, with the aim of generating a robust, clinically applicable test. qPCR takeoff point values from the training set were used for feature reduction/ signature refinement (penalised logistic regression), with final signature loop data used to train the predictive model (XGBoost algorithm). Predictive performance was internally validated using hitherto unseen test set data. To determine added value over routine data, performance was compared against predictive models trained and validated using the same populations and algorithms with i) clinical parameters alone, and ii) combined clinical plus chromatin loop data. Results: Baseline clinical parameters are shown in Table 1. 55/107 participants (51.4%) flared, while 52/107 (48.6%) remained in remission. In the discovery set, 625 differentially abundant stable loops were identified (fold change >1.1 and p-value <0.05). Of 22 candidates translated to qPCR, the top 10 following feature reduction were used to train the predictive model. Using the test set, the final 10-loop epigenomic model correctly called 21/24 flare and 17/21 remission participants, with classification accuracy (for flare) 84.2%, positive predictive value (PPV) 84.0%, and negative predictive value (NPV) 85.0%. A model using clinical parameters alone had accuracy 78.5%, PPV 93.8%, NPV 53.3%, while a combined clinical/ epigenomic model had accuracy 85.3%, PPV 93.8%, NPV 73.3% (see Table 2). The epigenomic model was optimal for guiding DMARD withdrawal decisions, as high NPV minimises risk of flare, potentially reducing flares per number of DMARD withdrawals from 1 in 2 (no test) to 1 in 7. Conclusion: A peripheral blood 10-loop chromosome conformation signature shows promise as an epigenomic biomarker for predicting flare following DMARD withdrawal. For the specific clinical context, the epigenomic model appears to offer enhanced predictive performance compared with clinical data, suggesting a simple blood test might be feasible. Such an approach could enable stratified decision making, to reduce unnecessary treatment exposure while minimising risk of flare. REFERENCES: [1] Baker et al. J Autoimmun. 2019.[2] Carini et al. J Transl Med. 2018.[3] Rayner et al. BMC Rheum. 2021. Acknowledgements: NIL. Disclosure of Interests: Andrew Melville MRC GSK EMINENT PhD Studentship, Tarun Naithani Employee of Oxford Biodynamics PLC, Amy E Anderson: None declared, Fiona Rayner: None declared, Sean Kerrigan Lectures for Vifor, Andrew McGucken: None declared, Bernard Dyke: None declared, Shaun Hiu: None declared, Jonathan Prichard: None declared, Jayne Green Employee of Oxford Biodynamics, Ryan Powell Employee of Oxford Biodynamics PLC, Catharien Hilkens Research funding from GSK, Christopher D Buckley: None declared, Iain B. Mc Innes Honoraria or research support from Abbvie, Janssen, Novartis, Eli Lilly, Astra Zeneca, GSK, BMS, Moonlake, Evelo, Causeway THerapeutics, Cabaletta, Roche, Pfizer and Compugen., Wan-Fai Ng: None declared, Andrew Filer: None declared, Karim Raza Research grant support from Bristol Myers Squibb and personal fees for lectures/ consultancy from Abbvie and Sanofi, Arthur Pratt: None declared, Kenneth F Baker Consulting fees from Modern Biosciences, Research support from Genentech and clinical improvement funding from Pfizer, Ewan Hunter Employee of Oxford Biodynamics PLC, John Isaacs Speaker fees from AbbVie, Consulting fees from Anaptys Bio, Annexon Biosciences, AstraZeneca, BMS, Cyxone AB, Eli Lilly, Galapagos NV, Gilead Sciences Ltd, GSK, Istesso Ltd, Janssen, Kenko International, Kira Biotech, Ono Pharma, Pfizer, Revelo Biotherapeutics, Roche and Sanofi, Research grants from Pfizer, Janssen and GSK, Stefan Siebert Speaker or consulting fees from AbbVie, Amgen, AstraZeneca, Eli Lilly, GSK, Janssen, UCB, Institutional research grants from Amgen (previously Celgene), Boehringer Ingelheim, Bristol Myers Squibb, Eli Lilly, GSK, Janssen and UCB, Carl S Goodyear: None declared.

Background: Rheumatoid arthritis (RA) flares remain poorly understood at a mechanistic level and have been difficult to study because of their sporadic nature. BIO-FLARE (BIOlogical Factors that Limit sustAined Remission in rhEumatoid arthritis; ISRCTN16371380) is an experimental medicine programme designed to scientifically study flares in RA, in which patients in remission stopped all DMARDs. We anticipated that 50% would develop disease flares over 6 months, providing matched flare and remission (control) groups to study. Objectives: Here we describe the main clinical characteristics and outcomes from the BIO-FLARE study, identify predictors of flare among routine baseline clinical parameters, and generate an exploratory clinical model to predict risk of flare. Methods: BIO-FLARE was a multi-centre, prospective, experimental medicine study [1]. Eligible RA patients in remission (DAS28-CRP <2.4) on conventional synthetic DMARDs (methotrexate, sulfasalazine, hydroxychloroquine) stopped all treatment without tapering and were followed up with multi-parameter immune monitoring at weeks 2, 5, 8, 12 and 24, or until flare if earlier. Ad-hoc study visits were arranged for suspected flare. The primary clinical outcome was time-to-flare, with flare defined as DAS28-CRP ≥3.2 at any visit, DAS28-CRP ≥2.4 if reconfirmed within 14 days, or other clinician adjudged flare not captured by DAS28. Sixteen baseline clinical variables were considered for inclusion in the predictive model (see Table 1). Univariate analyses were performed to assess strength of association between each candidate variable and time-to-flare. A set of predictive variables was formally selected through penalised Cox models. Predictive modelling was carried out using Cox proportional hazards methodology, and final model performance assessed by internal validation using bootstrapping. Results: 121 participants were recruited between September 2018 and December 2020. Baseline demographics are shown in Table 1. Mean (SD) age was 64.1 (11.9) years, 60.3% were female, and median (IQR) disease duration was 6.3 (4.5–12.3) years. 56.3% were RF positive, 66.7% were ACPA positive, 56.6% were double positive. 83.5% were on treatment with methotrexate (monotherapy or combination). At baseline, mean (SD) DAS28-CRP was 1.61 (0.32), 61.2% fulfilled ACR/EULAR Boolean remission criteria, and 84.9% fulfilled SDAI remission criteria. Over the 24-week study period, 52.3% had confirmed flare (95% CI 43.0–61.7), with median time-to-flare of 63 days (IQR 41–96 days, range 13–155 days). Mean (SD) DAS28-CRP at flare was 3.81 (0.78). Hazard ratios and confidence intervals for each baseline variable from univariate time-to-flare analyses are shown in Table 2. The variable selection process identified female sex, baseline methotrexate use, RF, and ACPA as significant predictors of flare. These variables were used to build a predictive model providing estimated risk of flare for each individual by a given timepoint, computed as 1- S0(t)exp(PI), where S0(t) is the baseline survival function (0.67 at 6 months), and PI is the prognostic index (propensity to flare). PI can be calculated as (-0.56 x sex) + (1.06 x methotrexate use) + (0.04 x √(RF+0.1)) + (0.56/(ACPA+0.1)) – (1.87/√(ACPA+0.1)). The model had acceptable classification performance (C index 0.709) and was well-calibrated (calibration slope 1.00). Conclusion: Approximately half of RA patients in remission on csDMARDs experienced flare within 6 months of stopping treatment, with median time-to-flare of 9 weeks. Female sex, baseline methotrexate use, RF and ACPA were predictors of flare. Our predictive model, based on routine clinical parameters only, provides an estimate of risk of flare at the individual level over time. To our knowledge, no comparable clinical model has been described previously in this context. Work is ongoing in BIO-FLARE to identify immune biomarkers to strengthen our model, and to provide wider insights into the underlying biology of flare and remission in RA. REFERENCES: [1] Rayner et al. BMC Rheumatology. 2021. Acknowledgements: NIL. Disclosure of Interests: Fiona Rayner: None declared, Shaun Hiu: None declared, Andrew Melville MRC GSK EMINENT PhD studentship, Theophile Bigirumurame: None declared, Amy E Anderson: None declared, Sean Kerrigan Honoraria from Vifor., Andrew McGucken: None declared, Bernard Dyke: None declared, Jonathan Prichard: None declared, Mohadeseh Shojaei Shahrokhabadi: None declared, Catharien Hilkens Research funding from GSK., Iain B. Mc Innes Honoraria or research support from Abbvie, Janssen, Novartis, Eli Lilly, Astra Zeneca, GSK, BMS, Moonlake, Evelo, Causeway THerapeutics, Cabaletta, Roche, Pfizer and Compugen., Wan-Fai Ng: None declared, Carl S Goodyear: None declared, Dawn Teare: None declared, Andrew Filer: None declared, Stefan Siebert Speaker or consulting fees from AbbVie, Amgen, AstraZeneca, Eli Lilly, GSK, Janssen, UCB., Institutional research grants from Amgen (previously Celgene), Boehringer Ingelheim, Bristol Myers Squibb, Eli Lilly, GSK, Janssen and UCB., Karim Raza Personal fees for lectures/ consultancy from Abbvie and Sanofi., Research grant support from Bristol Myers Squibb and Sanofi., Arthur Pratt: None declared, Kenneth F Baker Consulting fees from Modern Biosciences., Research support from Genentech and clinical improvement funding from Pfizer., John Isaacs Speaker fees from AbbVie., Consulting fees from Anaptys Bio, Annexon Biosciences, AstraZeneca, BMS, Cyxone AB, Eli Lilly, Galapagos NV, Gilead Sciences Ltd, GSK, Istesso Ltd, Janssen, Kenko International, Kira Biotech, Ono Pharma, Pfizer, Revelo Biotherapeutics, Roche and Sanofi., Research grants from Pfizer, Janssen and GSK.

Background: Promoting healthy eating and physical activity in early childhood education and care (ECEC) is recommended within guidelines and supported by health promotion programs; however, implementation is suboptimal. Evidence suggests implementation within the sector varies over time; however, this has not been empirically examined in relation to implementation barriers. This study aims to: (1) describe changes in the prevalence of, and barriers to, implementation of priority healthy eating and physical activity practices; and (2) explore the associations between such barriers and implementation.Methods: This was a repeated cross-sectional study over an 8-month period. A cross-section of 150-180 Australian ECEC services were prospectively randomly sampled for each month (April-November 2023), with 1127 ECEC services sampled in total and 20% of services sampled twice. Services reported via survey their implementation of two priority practices: (1) healthy menu standards and (2) educating and engaging parents in child physical activity. They also reported on implementation status, implementation stage, and five core implementation barriers.Results: Overall, 716 services completed 809 surveys. There were no significant differences in the prevalence of implementation or general trends in barriers to implementation of the two priority practices across that time. Services reporting less barriers were significantly more likely to be implementing the priority practices, and services in more advanced implementation stages were significantly less likely to report barriers.Conclusions: To enhance the implementation of priority practices in ECEC services, key barriers to implementation need to be understood and targeted to progress services through to advanced implementation stages.