Precision Medicine With Leflunomide: Consideration of the DHODH Haplotype and Plasma Teriflunomide Concentration and Modification of Outcomes in Patients With Rheumatoid Arthritis.

OBJECTIVE: Leflunomide is a commonly used disease-modifying drug in the treatment of rheumatoid arthritis (RA). Its effects are mediated via inhibition of dihydroorotate dehydrogenase (DHODH) by its active metabolite teriflunomide, and the pharmacokinetics of teriflunomide are highly variable. Our objective was to examine the association between the DHODH haplotype and plasma teriflunomide concentration with response to leflunomide in patients with RA where leflunomide was added to an existing disease-modifying drug regimen after failure to achieve an adequate response with conventional triple therapy. METHODS: Patients with RA who were taking, or were about to initiate, leflunomide were included. Participant characteristics, including the DHODH haplotype, were determined. Up to 5 plasma samples were collected after leflunomide was initiated for assays of total and free teriflunomide concentration. Disease activity was determined via the 28-joint Disease Activity Score (DAS28). The association between DAS28 scores and patient covariates was determined by linear mixed-effects modeling. RESULTS: A total of 67 patients were included in the study. The DAS28 score after initiation of leflunomide was associated with the baseline DAS28 score (ß = 0.70, P < 0.001) and was higher in those who carried the DHODH haplotype 2 (ß = 0.56. P = 0.01) and did not carry the shared epitope (ß = 0.56, P = 0.013). As total and free plasma teriflunomide concentration increased, the DAS28 score was significantly lower (P < 0.001 and P = 0.001, respectively). When considering threshold concentrations, teriflunomide concentrations >16 mg/liter were associated with a DAS28 score that was 0.33 lower, and when free teriflunomide concentration was >35 µg/liter, the DAS28 score was 0.32 lower. CONCLUSION: Teriflunomide concentration and carriage of the DHODH haplotype 2 are associated with response to leflunomide in patients with RA, and a total plasma teriflunomide concentration of at least 16 mg/liter is needed to maximize the likelihood of response.

Modifiable Lifestyle Factors Associated With Response to Treatment in Early Rheumatoid Arthritis.

OBJECTIVE: We aimed to evaluate the associations between response to algorithm-directed treat-to-target conventional synthetic disease-modifying antirheumatic drug therapy and potentially modifiable lifestyle factors, including dietary fish oil supplementation, body mass index (BMI), and smoking history in a rheumatoid arthritis (RA) inception cohort. METHODS: Patients with RA with a duration of less than 12 months were reviewed every 3 to 6 weeks to adjust therapy according to disease response. All patients received advice to take fish oil supplements, and omega-3 status was measured as plasma levels of eicosapentaenoic acid (EPA). Lifestyle factors and other variables potentially prognostic for 28-joint Disease Activity Score (DAS28) remission and DAS28 low disease activity (LDA) at the 12-month visit were included in multivariable logistic regression models. RESULTS: Of 300 participants, 57.7% reached DAS28 LDA, and 43.7% were in DAS28 remission at 1 year. Increase in plasma EPA was associated with an increase in the odds of being in LDA (adjusted odds ratio [OR] = 1.27; P < 0.0001) and remission (adjusted OR = 1.21; P < 0.001). There was some evidence that the effect of BMI on LDA might be modified by smoking history. An increase in BMI was associated with a decrease in the odds of being in LDA in current and former smokers but had no impact on LDA in patients who had never smoked. There were no meaningful associations between BMI or smoking history and remission. CONCLUSION: Omega-3 status, BMI, and smoking history are potential predictors of outcome in early RA. The possibility of an effect modification by smoking on the predictive value of BMI merits further investigation.

Scleroderma in Cairns: an epidemiological study.

BACKGROUND: Systemic sclerosis (SSc) refers to an autoimmune fibrosing disorder with high disease burden and mortality. The prevalence of 23/100 000 in South Australia (SA) is among the highest documented, but anecdotally it is higher still in Cairns. AIMS: To ascertain the prevalence of SSc in Cairns and surrounding regions, and to compare the demographic and clinical characteristics of patients with SSc in Cairns with those in SA. METHODS: Patients with SSc in Cairns were ascertained through hospital records and by referrals from specialist physicians in the region. These patients were interviewed and completed a structured questionnaire. Their physical findings and autoantibodies were recorded. These patients were compared with the SA patients enrolled in the Australian Scleroderma Cohort Study. RESULTS: A total of 81 patients was identified in Cairns, giving an estimated cross-sectional prevalence of 33.7/100 000. Among 65 patients interviewed in Cairns, 23 were born in Cairns, 16 had migrated to Cairns to ameliorate their Raynaud phenomenon and 26 for other reasons. The clinical features in both cohorts were similar, although Cairns had a lower prevalence of digital ulcers (30.8% vs 46.6%; odds ratio (OR) = 0.5035, 95% confidence interval (CI): 0.2839-0.8929, P = 0.0271) and higher prevalence of calcinosis (29.2% vs 17.0%; OR = 2.005, 95% CI: 1.055-3.382). CONCLUSIONS: The higher prevalence of SSc in Cairns is partly, but not completely, due to migration. Differences in clinical features are not entirely explained by the warmer climate. There is a need for greater rheumatologic services in the Cairns region.

Determining the acceptable level of physician compliance with a treat-to-target strategy in early rheumatoid arthritis.

OBJECTIVE: To determine the minimum cut-points for rate of physician compliance with a treat-to-target (T2T) strategy needed to achieve optimal rates of remission or low disease activity (LDA). METHOD: In this analysis of longitudinal observational data from patients with early RA, physician compliance with a T2T treatment protocol was determined for each clinic visit over 3 years. Remission and LDA were measured by Disease Activity Score in 28 joints (DAS28), simplified disease activity index (SDAI) and clinical disease activity index (CDAI). The minimum physician compliance rates for predicting these outcomes were calculated using receiver operating characteristic (ROC) curves. RESULT: Overall, 149 patients completed 3078 clinic visits over 3 years of follow-up. Treatment decisions complied with the T2T protocol in 2343 of these visits (76.1%). The minimum cut-points for physician compliance rates that predicted remission and LDA according to DAS28 were 81.1% and 70.7%, respectively, and to predict remission and LDA according to SDAI, the respective cut-points were 92.7% and 77.4%. Based on these cut-points, three categories of physician compliance with T2T were proposed: high (to maximize the likelihood of achieving remission, > 80% according to DAS28 or > 90% according to SDAI/CDAI); medium (the minimal physician compliance to achieve LDA, 70-79% according to DAS28 or 75-89% for SDAI/CDAI); and low (< 70% for DAS28 and < 75% for SDAI/CDAI), where remission and LDA are unlikely). When patients were stratified by baseline disease activity, the physician compliance rate cut-points were similar for most outcomes at year 3. CONCLUSION: Using real-life clinical data, we determined the thresholds for physician compliance with a T2T strategy that stratified patients according to their disease outcomes and proposed a system for classifying physician compliance as high, medium and low.

Effect of Adherence to Protocolized Targeted Intensifications of Disease-modifying Antirheumatic Drugs on Treatment Outcomes in Rheumatoid Arthritis: Results from an Australian Early Arthritis Cohort.

OBJECTIVE: To investigate the association between adherence to treat-to-target (T2T) protocol and disease activity, functional outcomes, and radiographic outcomes in early rheumatoid arthritis (RA). METHODS: Data from a longitudinal cohort of patients with early RA were used. Adherence was determined at each followup visit over 3 years according to predefined criteria. The primary endpoint was remission according to Disease Activity Score in 28 joints (DAS28) and Simplified Disease Activity Index (SDAI) criteria. Functional and radiographic outcomes measured by modified Health Assessment Questionnaire and modified total Sharp score, respectively, were secondary endpoints. RESULTS: A total of 198 patients with 3078 clinic visits over 3 years were included in this analysis. After adjusting for relevant variables, although there was no significant association between adherence to T2T and remission rate after 1 year, the associations reached significance after 3 years for both DAS28 (OR 1.71, 95% CI 1.16-2.50; p = 0.006) and SDAI criteria (OR 1.94, 95% CI 1.06-3.56; p = 0.033). After 3 years, adherence was also associated with improvement in physical function (ß=0.12, 95% CI 0.06-0.18; p < 0.0001). None of the radiographic outcomes were associated with adherence after either 1 or 3 years, although there was a trend for higher adherence to be associated with less radiographic progression at the end of the study (p = 0.061). CONCLUSION: Increased adherence to T2T was associated with better longterm disease activity and functional outcomes, which suggests that the benefit of a T2T protocol may be enhanced by ensuring adequate adherence.

Plasma n-3 fatty acids and clinical outcomes in recent-onset rheumatoid arthritis.

A randomised controlled trial (RCT) of high-dose v. low-dose fish oil in recent-onset rheumatoid arthritis (RA) demonstrated that the group allocated to high-dose fish oil had increased remission and decreased failure of disease-modifying anti-rheumatic drug (DMARD) therapy. This study examines the relationships between plasma phospholipid levels of the n-3 fatty acids in fish oil, EPA and DHA, and remission and DMARD use in recent-onset RA. EPA and DHA were measured in blood samples from both groups of the RCT. The data were analysed as a single cohort, and Cox proportional hazards models were used to examine relationships between plasma phospholipid (PL) EPA and DHA and various outcome measures. When analysed as a single cohort, plasma PL EPA was related to time to remission, with a one unit increase in EPA (1% total fatty acids) associated with a 12% increase in the probability of remission at any time during the study period (hazard ratio (HR)=1.12; 95% CI 1.02, 1.23; P=0.02). Adjustment for smoking, anti-cyclic citrullinated peptide antibodies and 'shared epitope' HLA-DR allele status did not change the HR. Plasma PL EPA, adjusted for the same variables, was negatively related to time to DMARD failure (HR=0.85; 95% CI 0.72, 0.99; P=0.047). The HR for DHA and time to remission or DMARD failure were similar in magnitude to those for EPA, but not statistically significant. Biomarkers of n-3 status, such as plasma PL EPA, have the potential to predict clinical outcomes relevant to standard drug treatment of RA patients.

Characterising deviation from treat-to-target strategies for early rheumatoid arthritis: the first three years.

INTRODUCTION: Treat-to-target (T2T) strategies using a protocol of pre-defined adjustments of disease-modifying anti-rheumatic drugs (DMARDs) according to disease activity improve outcomes for patients with rheumatoid arthritis (RA). However, successful implementation may be limited by deviations from the protocol. The aim of this study was to determine the prevalence of protocol deviation, explore the reasons and identify subsets of patients in whom treatment protocols are more difficult to follow. METHODS: In this retrospective cohort study, treatment-naïve patients with RA of less than one year's duration, attending a dedicated early arthritis clinic between 2001 and 2013, were followed for three years from initiation of combination therapy with conventional DMARDs which was subsequently modified according to a T2T protocol. At each clinic visit, whether deviation from the protocol occurred, the type of deviation and the reasons for deviation were assessed. The relationship between protocol deviations and baseline variables was determined using linear regression analysis. RESULTS: In total, 198 patients contributed 3,654 clinic visits. The prevalence of protocol deviations was 24.5% and deviation in at least at one clinic visit was experienced by 90.4% of patients. The median time to first deviation was 30 weeks. Continuing existing treatment rather than intensifying therapy was the most common type of deviation (59.9%). Patient and physician related factors were the most common reasons for deviation, each accounting for 24.7% of deviations, followed by toxicities (23.3%) and comorbidities (20.0%). The prevalence of protocol deviations was lower among patients who achieved remission after three years (13.1%; 162 deviations out of 1,228 visits) compared with those who were not in remission (30.9%; 523/1692) (P<0.0001). On multivariate analysis, only body mass index (P=0.003) and helplessness score (P=0.04) were independent predictors of protocol deviations although the predictive power of the model was not strong (R2=0.17). CONCLUSIONS: Deviation from a T2T protocol occurred in one quarter of visits, indicating that applying the T2T approach is feasible in clinical practice. Failure to escalate dose when indicated was commonly encountered, and just under half of the observed deviations were related to either toxicities or comorbidities and were therefore justifiable on clinical grounds.

Fish oil in recent onset rheumatoid arthritis: a randomised, double-blind controlled trial within algorithm-based drug use.

BACKGROUND: The effects of fish oil (FO) in rheumatoid arthritis (RA) have not been examined in the context of contemporary treatment of early RA. This study examined the effects of high versus low dose FO in early RA employing a 'treat-to-target' protocol of combination disease-modifying anti-rheumatic drugs (DMARDs). METHODS: Patients with RA <12 months' duration and who were DMARD-naïve were enrolled and randomised 2:1 to FO at a high dose or low dose (for masking). These groups, designated FO and control, were given 5.5 or 0.4 g/day, respectively, of the omega-3 fats, eicosapentaenoic acid + docosahexaenoic acid. All patients received methotrexate (MTX), sulphasalazine and hydroxychloroquine, and DMARD doses were adjusted according to an algorithm taking disease activity and toxicity into account. DAS28-erythrocyte sedimentation rate, modified Health Assessment Questionnaire (mHAQ) and remission were assessed three monthly. The primary outcome measure was failure of triple DMARD therapy. RESULTS: In the FO group, failure of triple DMARD therapy was lower (HR=0.28 (95% CI 0.12 to 0.63; p=0.002) unadjusted and 0.24 (95% CI 0.10 to 0.54; p=0.0006) following adjustment for smoking history, shared epitope and baseline anti-cyclic citrullinated peptide. The rate of first American College of Rheumatology (ACR) remission was significantly greater in the FO compared with the control group (HRs=2.17 (95% CI 1.07 to 4.42; p=0.03) unadjusted and 2.09 (95% CI 1.02 to 4.30; p=0.04) adjusted). There were no differences between groups in MTX dose, DAS28 or mHAQ scores, or adverse events. CONCLUSIONS: FO was associated with benefits additional to those achieved by combination 'treat-to-target' DMARDs with similar MTX use. These included reduced triple DMARD failure and a higher rate of ACR remission.

Porphyromonas gingivalis peptidylarginine deiminase substrate specificity.

UNLABELLED: While a group of oral commensals have been implicated in the aetiology of chronic periodontitis; the asaccharolytic Gram negative anaerobe Porphyromonas gingivalis is most commonly reported to be associated with severe forms of the disease. Although a variety of human tissues can produce a number of peptidylarginine deiminase (PAD), enzymes that convert peptide bound arginine residues to citrulline, P. gingivalis is one of the few prokaryotes known to express PAD. Protein and peptide citrullination are important in the development of rheumatoid arthritis and in recent years a number of authors have suggested a possible link between periodontitis and rheumatoid arthritis (RA). Indeed, some have linked P. gingivalis directly to RA via the action of PAD. Accordingly, the prime purpose of this study was to further characterise PAD in P. gingivalis cells particular emphasis on substrate specificity, using arginine containing peptides and RA relevant proteins. METHODS: P. ginigvalis W50 was anaerobically cultured in BHI broth, cells harvested and resuspended in assay buffer. A colourimetric assay was developed to measure citrulline and employed to determine enzyme activity using the substrate BAEE. The assay was employed to investigate the effects of environmental pH and temperature on activity. Citrullination of BAEE by sonicated cells allowed the proportion of intracellular enzyme to be estimated. Enzyme specificity and substrate preference were investigated by using various arginine containing peptides, proteins and arginine analogues, as substrates and measuring the rate of citrullination. The influence of gingipains on citrullination was assessed by measuring the rates of citrullination of bovine serum albumin in the presence of protease inhibitors. RESULTS: Enzyme activity decreased by 13% following exposure of cells to 60 °C for 10 min. A comparison of intact and disrupted cells indicated that 90% of PAD activity is cell surface associated and the remainder cytoplasmic. Optimal pH for enzyme activity was between pH 7.5 and 8. All small arginine-containing peptides were citrullinated with reaction rates faster than that for free arginine with rates that varied with arginine residue position and number. Arginine analogues exhibited minimal effect and influence when tested as either substrates or competitive inhibitors. Cells were able to citrullinate yeast enolase, human vimentin and fibrin at varying rates. All proteins were modified at slower rates than those for peptide substrates. Inhibition of gingipains had no influence on the rate of protein citrullination. CONCLUSIONS: P. gingivalis PAD is a primarily cell surface associated, heat stable, enzyme that exhibits optimal activity under alkaline conditions similar to those present in the inflammatory environment. The enzyme displays high specificity for arginine residues in peptides and modified arginine in all positions and the gingipains did not influence the rate of protein citrullination. The ability of the enzyme to convert arginine residues in all proteins tested would indicate that its presence in inflamed tissue may promote autoimmune reactions by creation of altered host epitopes.

Association of DHODH haplotype variants and response to leflunomide treatment in rheumatoid arthritis.

AIM: Leflunomide is a disease-modifying antirheumatic drug used in the treatment of rheumatoid arthritis. Not all patients respond to leflunomide and, as it has potentially serious side effects, targeting only those most likely to benefit would address a clinical need. We aimed to determine whether variations in the gene encoding DHODH, the molecular target of leflunomide, might include biomarkers that could be used to rationalize provision of this drug. MATERIALS & METHODS: We analyzed six haplotype-tagging SNPs in DHODH in 56 patients with rheumatoid arthritis treated with leflunomide. Clinical response was determined by assessing the change in 28 joint disease activity score over the first 3 months of treatment. RESULTS & CONCLUSION: Carriage of a six-marker DHODH haplotype was associated with a reduced treatment response (p = 0.008). This suggests that a functional variant in strong linkage disequilibrium with this haplotype may predispose to reduced leflunomide efficacy.

Polymorphisms in cytochrome P450 2C19 enzyme and cessation of leflunomide in patients with rheumatoid arthritis.

INTRODUCTION: Rational selection of disease modifying anti-rheumatic drugs in the treatment of rheumatoid arthritis (RA) has many potential advantages, including rapid disease control, reduced long-term disability and reduced overall cost to the healthcare system. Inter-individual genetic differences are particularly attractive as markers to predict efficacy and toxicity, as they can be determined rapidly prior to drug selection. The aims of this study, therefore, were to investigate the association between differences in genes associated with the metabolism, clearance and efficacy of leflunomide with its cessation in a group of rheumatoid arthritis patients who were treated with an intensive contemporary, treat-to-target approach. METHODS: This retrospective cohort study identified all individuals who received leflunomide and were enrolled in the Early Arthritis inception cohort at the Royal Adelaide Hospital between 2001 and July 2011. Inclusion criteria were age (>18) and a diagnosis of rheumatoid arthritis. Patients were excluded if a DNA sample was not available, if they withdrew from the cohort or if clinical data were insufficient. Subjects were followed for 12 months or until either another disease modifying antirheumatic drug was added or leflunomide was ceased. The following single nucleotide polymorphisms (SNPs) were determined: CYP2C19*2 (rs4244285), CYP2C19*17 (rs12248560), ABCG2 421C>A (rs2231142), CYP1A2*1F (rs762551) and DHODH 19C>A (rs3213422). The effects of variables on cessation were assessed with Cox Proportional Hazard models. RESULTS: Thirty-three of 78 (42.3%) patients ceased leflunomide due to side effects. A linear trend between cytochrome P450 2C19 (CYP2C19) phenotype and leflunomide cessation was observed, with poor and intermediate metabolizers ceasing more frequently (adjusted Hazard Ratio = 0.432 for each incremental change in phenotype, 95% CI 0.237 to 0.790, P = 0.006). Previously observed associations between cytochrome P450 1A2 (CYP1A2) and dihydro-orotate dehydrogenase (DHODH) genotype and toxicity were not apparent, but there was a trend for ATP-binding cassette sub-family G member 2 (ABCG2) genotype to be associated with cessation due to diarrhea. CONCLUSIONS: CYP2C19 phenotype was associated with cessation due to toxicity, and since CYP2C19 intermediate and poor metabolizers have lower teriflunomide concentrations, it is likely that they have a particularly poor risk:benefit ratio when using this drug.

Recruitment and proliferation of CD4+ T cells in synovium following adoptive transfer of adjuvant-induced arthritis.

Adjuvant-induced arthritis can be transferred to naive Dark Agouti (DA) strain (DA.CD45.1) rats by thoracic duct (TD) lymphocytes. Disease can be re-induced in convalescent rats by further transfer of arthritogenic cells, suggesting that resolution of the adoptive disease is not due to active regulation. To examine whether resolution is due to exhaustion of effector cells, we transferred the disease to DA.CD45.1 recipients, using CD4+ T cells from DA.CD45.2 donors. At the height of the adoptively transferred disease, donor cells comprised only 5-10% of recirculating CD4+ T cells but they accounted for approximately 40% of the CD4+ T cells in synovium-rich tissues of the hind paws. Approximately 65% of the donor cells in the synovium expressed a marker of proliferation (Ki-67 antigen). Division of CD4+ T cells continued in shielded paws after suppression of the recirculating pool of lymphocytes by selective irradiation. Intravenously injected CD4+ TD T lymphoblasts from arthritic donors were recruited to normal paws and, in greater numbers, to paws of animals with existing arthritis. Survival of the [125I]iodo-deoxyuridine-labeled lymphoblasts was greater in animals with existing arthritis. We conclude that effector CD4+ T cells in target tissues can proliferate in response to autoantigens and exhibit enhanced survival. However, without a continuous supply, adoptively transferred effector cells do not produce autonomous local disease, due to limits to their lifespan and ability to replicate indefinitely.

Blockade of IFN-gamma does not affect the arthritogenicity of T cells generated during the induction of adjuvant arthritis but exacerbates the polyarthritis produced by adoptive transfer of arthritogenic effector cells.

IFN-gamma production is prominent in some models of autoimmune disease, including adjuvant arthritis (AA), but the role of IFN-gamma in the pathogenesis of these diseases is uncertain. Experimental manipulation (administration of cytokine, blocking cytokine action with specific antibody, disruption of genes encoding the cytokine or its receptor) has revealed both pro- and anti-inflammatory effects, depending on the nature of the manipulation and the timing of the treatment. We examined separately the effects of cytokine blockade during the afferent and efferent phases of AA in Dark Agouti rats, using an adoptive transfer system. Effects of IFN-gamma on the efferent phase were investigated by treating recipients with mAb DB-1, which blocks the activity of rat IFN-gamma. When treatment was commenced before cell transfer, the resulting polyarthritis was more severe than in controls treated with normal IgG. Commencing treatment after the adoptively transferred disease had become established caused neither amelioration nor exacerbation, but did cause some delay in resolution. In contrast, treatment of donors did not appear to affect the generation of arthritogenic cells. The main effect of IFN-gamma appears to be modulation of the arthritogenicity of the migratory effector T cells that can transfer AA.

Temporal changes in the distribution of thoracic duct lymphoblasts to synovium and other tissues of rats with adjuvant-induced arthritis.

The distribution of lymphoblasts(lymphocytes in cell cycle) obtained from the central lymph of donor rats and transferred adoptively to syngeneic recipients has been shown previously to be influenced by the presence of arthritis in either donor or recipient rats. The intent of the present study was to examine patterns of distribution of lymphoblasts in the early period after transfer, when extravasation of donor lymphoblasts was expected to occur. Thoracic duct lymphoblasts labelled in vitro with [125I]-iododeoxyuridine were detected in recipient rats by external radiometry and autoradiography. Irrespective of donor status, fewer donor lymphoblasts accumulated in the feet of normal recipients when compared to arthritic recipients at 15 min, 2 h and 24 h after cell transfer.When recipients of similar disease status were compared, the percentages of injected lymphoblasts from normal and arthritic donors recovered in the feet were similar at 15 min and 2 h after transfer. The proportions of lymphoblasts recovered in the feetat 24 h after injection declined in normal recipients and arthritic recipients of cells from normal donor rats. Importantly,this decline did not occur when both the donor and the recipient were arthritic. In the hindpaws, donor lymphoblasts were located predominantly in the bone marrow, except in transfers between arthriticrats, when at 24 h they were predominantly in the synovium. At 15 min, lymphoblasts were detected within the lumen of vessels within synovium, whereas by 2 h extravasation of these cells was evident. In conclusion, lymphoblasts accumulate more readily in hindfeet that are inflamed. In the early hours after injection, lymphoblasts from normal and arthritic donors are recruited equally, but these early levels are only maintained for 24 hin the combination of arthritic donor and arthritic recipient. Adramatic change in the proportion of lymphoblasts located in synoviumat this later time suggests that a dynamic process of relocation,retention and/or local cell division maintains the numbers of arthritic donor cells in the latter combination.