Stratified medicine in inflammatory disorders: From theory to practice.

Chronic inflammatory disorders are complex and characterized by significant heterogeneity in molecular, pathological, and clinical features. This heterogeneity poses challenges for the development of targeted molecular interventions for these disorders, as not all patients with a given clinical diagnosis have disease driven by a single dominant molecular pathway, hence not all patients will benefit equally from a given intervention. Biomarkers related to molecular manifestations of disease are increasingly being applied to enable stratified approaches to drug development. Biomarkers may be used to identify which patients are most likely to benefit from an intervention (predictive), identify patients at increased risk of disease progression (prognostic), and monitor biological responsiveness to an intervention (pharmacodynamic). Here we consider how biomarker-guided stratification of patients may increase benefit from targeted therapies for asthma, rheumatoid arthritis and inflammatory bowel diseases.

Clinical outcomes in a cohort of Colombian patients with rheumatoid arthritis treated with Etanar, a new biologic type rhTNFR:Fc.

OBJECTIVES: To evaluate the clinical response at 12 month in a cohort of patients with rheumatoid arthritis treated with Etanar (rhTNFR:Fc), and to register the occurrence of adverse effects. METHODS: This is a multicentre observational cohort study. It included patients over 18 years of age with an active rheumatoid arthritis diagnosis for which the treating physician had begun a treatment scheme of 25 mg of subcutaneous etanercept (Etanar ® 25 mg: biologic type rhTNFR:Fc), twice per week. Follow-up was done during 12 months, with assessments at weeks 12, 24, 36 and 48. Evaluated outcomes included tender joint count, swollen joint count, ACR20, ACR50, ACR70, HAQ and DAS28. RESULTS: One-hundred and five (105) subjects were entered into the cohort. The median of tender and swollen joint count, ranged from 19 and 14, respectively at onset to 1 at the 12th month. By month 12, 90.5% of the subjects reached ACR20, 86% ACR50, and 65% ACR70. The median of DAS28 went from 4.7 to 2, and the median HAQ went from 1.3 to 0.2. The rate of adverse effects was 14 for every 100 persons per year. No serious adverse effects were reported. The most frequent were pruritus (5 cases), and rhinitis (3 cases). CONCLUSIONS: After a year of following up a patient cohort treated with etanercept 25 mg twice per week, significant clinical results were observed, resulting in adequate disease control in a high percentage of patients with an adequate level of safety.

[MMP-3 as a Biomarker of Disease Activity of Rheumatoid Arthritis].

The aim of this study was to confirm the clinical significance of serum MMP-3 measurement in the evalua- tion of disease activity and effectiveness of treatment in patients with rheumatoid arthritis (RA). MMP-3 was measured for 206 outpatients with RA during a period of 4 months, and also serially measured for RA patients treated with methotrexate(MTX) alone or together with infliximab (IFX). Serum MMP-3 was significantly correlated with CRP, SAA, and ESR. Significant correlation of serum MMP-3 was found not only with DAS28 (CRP) in female and male patients (p <0.0001 and p < 0.0051, respectively) but also with the EULAR classification criteria for the disease activity of RA. Among the items of DAS28(CRP), the strongest association of MMP-3 was found with swollen joint counts. Furthermore, MMP-3 levels increased with advances in Stage and Class of RA. MMP-3 levels gradually decreased 12 and 24 weeks after successful treatment with MTX (p=0.0188 and p=0.0179, respectively). Extent of the decrease was more prominent in patients with better response to MTX than in those with poor response. MMP-3 levels significantly decreased 6 weeks after IFX treatment and continued to decrease until 48 weeks. Significant decrease of MMP-3 level from before treatment was shown only in the good response group to IFX after 48 weeks of treatment. MMP-3 level was shown to be useful as a disease activity marker in RA patients. In addition, serial measurement of MMP-3 maybe helpful to evaluate the effect of treatments with MTX and IFX.

Vertebral fractures affect functional status in postmenopausal rheumatoid arthritis patients.

Functional disability is a major concern in patients with rheumatoid arthritis (RA). This retrospective study investigated the risk factors for vertebral fractures (VFs) in postmenopausal RA patients and determined the impact of VFs on functional status. Data from a cohort of 200 postmenopausal RA patients in a single hospital registry were analyzed. Demographic and clinical data, imaging data from spine radiographs, and bone mineral density (BMD) data were collected from the patients at baseline and at the final visit (a mean of 2.9 years after the first visit). Risk factors for incident VFs and their impact on the modified health assessment questionnaire (mHAQ) were analyzed. Twenty-eight patients (14%) developed new VFs (NVFs). Logistic regression analysis adjusted for age, BMI, and disease duration revealed that daily dose of prednisolone, femoral neck BMD, use of active vitamin D3, and use of a bisphosphonate at baseline were factors associated with NVF, with odds ratios (95% confidence interval) of 1.27 (1.05-1.54), 0.94 (0.91-0.97), 0.34 (0.13-0.89), and 0.31 (0.12-0.82), respectively. Patients with NVF exhibited worse mHAQ scores and a greater increase in mHAQ scores from baseline compared with those without NVF. In conclusion, incident VFs were associated with reduced functional status in postmenopausal patients with RA. It is important to prevent VFs to maintain the functional status of RA patients.

Local synovial engagement of angiogenic TIE-2 is associated with the development of persistent erosive rheumatoid arthritis in patients with early arthritis.

OBJECTIVE: To examine the role of vascular endothelial growth factor (VEGF) and angiopoietin signaling in the diagnosis and disease outcome of patients with early arthritis. METHODS: Fifty patients with early arthritis (disease duration <1 year) who had not been treated with disease-modifying antirheumatic drugs (DMARDs) were monitored prospectively and were classified at baseline and after 2 years as having undifferentiated arthritis (UA), rheumatoid arthritis (RA), or spondyloarthritis (SpA). All patients underwent arthroscopic synovial biopsy at baseline. Synovial expression of VEGF, VEGF receptor, angiopoietin 1 (Ang-1), Ang-2, TIE-2, and activated p-TIE-2 was evaluated by immunohistochemistry. Serum levels of VEGF, Ang-1, and Ang-2 were measured by enzyme-linked immunosorbent assay. Secreted products of macrophages stimulated with Ang-1 and Ang-2 were measured using a multiplex system. RESULTS: Expression of Ang-1 was comparable between the patients with RA at baseline and patients with UA who fulfilled the criteria for RA over time (UA/RA), and it was significantly higher in patients with RA (P < 0.05) or UA/RA (P < 0.005) than in patients with SpA. TIE-2 and p-TIE-2 were more highly expressed in patients with RA (P < 0.005) or UA/RA (P < 0.05) than in patients with SpA. Ang-1 significantly enhanced the tumor necrosis factor-dependent macrophage production of cytokines and chemokines that are known to be elevated in the synovial fluid of patients with early RA. In RA, relative TIE-2 activation predicted the development of erosive disease (R(2) = 0.35, P < 0.05). CONCLUSION: Local engagement of synovial TIE-2 is observed during the earliest phases of RA, suggesting that TIE-2 signaling may contribute to disease development and progression or may indicate an attempt to protect against these processes. Early therapeutic targeting of TIE-2 signaling may be useful in improving outcome in arthritis.

The fibroid phenotype of biological naïve patients with rheumatoid arthritis are less likely to respond to anti-IL-6R treatment.

Type III collagen gene expression is upregulated in the synovium of patients with rheumatoid arthritis (RA) presenting the fibroid phenotype. The soluble type III collagen formation biomarker, PRO-C3, is known to measure fibrogenesis in fibrotic diseases. In this exploratory study, we aimed to investigate the association between fibrogenesis (PRO-C3) and the disease- and treatment response in patients with RA. We measured PRO-C3 in subsets of two clinical trials assessing the effect of the anti-interleukin-6 (IL-6) receptor treatment tocilizumab (TCZ) as monotherapy or polytherapy with methotrexate. PRO-C3 levels had weak or very weak correlations with the clinical parameters (Spearman's). However, when the patients were divided into Disease Activity Score-28 groups characterized by the erythrocyte sedimentation rate (DAS28-ESR), there was a statistical difference between the PRO-C3 levels of the different groups (p < 0.05). To determine the response in relation to PRO-C3, a cut-off based on PRO-C3 levels and patients in remission (DAS28-ESR ≤ 2.6) was identified. This showed that a reduction in PRO-C3 after treatment initiation was associated with decreased DAS28-ESR and a higher response rate in patients with low PRO-C3 levels than in those with high PRO-C3 levels. This indicates that a fibrotic component affects the responsiveness of patients.

[Rheumatoid arthritis and bone -periarticular and systemic bone loss-].

In rheumatoid arthritis (RA) , the osteoclast pathway is activated by an abnormal immune condition accompanied by chronic inflammation, resulting in periarticular osteoporosis and local bone destruction around joints. In addition, multiple factors including pharmacotherapies such as steroids, and reduced physical activity, lead to systemic osteoporosis. These conditions expose patients to increased fracture risk. In RA treatment, it is important to achieve suppression of fracture risk by controlling inflammation, which is associated with periarticular osteoporosis and bone destruction, using disease-modifying anti-rheumatic drugs or biologic agents and by improving systemic osteoporosis using anti-osteoporotic agents.

Phytochemicals targeting JAK/STAT pathway in the treatment of rheumatoid arthritis: Is there a future?

Rheumatoid arthritis (RA) is a chronic autoimmune disorder and the treatment involves the use of traditional and biological disease modifying anti-rheumatic drugs (DMARDs). Recent studies have shown JAK/STAT signaling pathway as potential target for the treatment of RA. Novel JAK/STAT inhibitors viz tofacitinib and baricitinib have been recently approved by FDA for RA treatment and have attained substantial importance. However, the discernible risks of thromboembolism, gastrointestinal (GIT) perforations, hepatotoxicity and serious infections including tuberculosis, herpes zoster associated with their administration cannot be overlooked. Furthermore, these are highly expensive which limits their application for a broader use. These limitations provide the basis of exploring novel JAK/STAT inhibitors of natural origin with increased tolerability, safety and cost-effectiveness. In this review we confer an account of various natural compounds/phytochemicals that have proved to be beneficial in attenuating inflammation in RA via modulation of JAK/STAT signaling pathway. Some of these natural compounds including resveratrol have clearly indicated biochemical and clinically significant therapeutic effects in ameliorating RA both in vivo and in clinical settings. We further discuss the physicochemical challenges of poor solubility and absorption coupled with the use of natural JAK/STAT inhibitors. We thereafter discuss and summarize various drug delivery systems (DDS) to confront the physicochemical limitations of natural JAK/STAT inhibitors with the aim to enhance the therapeutic efficacy. Overall the review unveils the potential of natural JAK/STAT inhibitors as a cost-effective approach in ameliorating RA without incorporating the risks of adverse repercussions, thus setting the stage for clinical exploration of these compounds that may possibly complement the present RA therapy.

Emerging Therapeutic Effects of Herbal Plants in Rheumatoid Arthritis.

Rheumatoid arthritis is a chronic inflammatory autoimmune disease characterized by the failure of spontaneous resolution of inflammation with lifetime perseverance, becoming one of the major causes of disability in millions of people. It is mainly characterized by progressive erosion of cartilage in response to the formation of pannus leading to chronic polyarthritis and joint distortion. Early diagnosis and advances in molecular biology undoubtedly revolutionized therapeutic interventions in the past decade for better disease management. Despite favorable prospects, many patients still fail to respond to the current therapies urging a burning need to develop newer and safer medications. Herbal plants have been utilized since the ancient era and provided the base for massive bioactive compounds with flaunting therapeutic potential, many being advanced to drugs that are consumed worldwide for treating countless ailments. Scientific studies showed the involvement of several cellular mechanisms like oxidative stress suppression, downregulated synthesis of proinflammatory cytokines namely interleukins (IL-1, IL-6), TNF-α, NF-κB, demoted metalloproteinases induced cartilage destruction and augmentation of free radical scavenging and antioxidant activity in the treatment of rheumatoid arthritis. A plethora of active phytoconstituents like flavonoids, saponins, terpenes, alkaloids, lactones, etc, have been isolated from herbal plants with proven curative actions. The present review enlists some of the herbal drugs that can be used to amend the effects of rheumatoid arthritis and impart symptomatic relief to patients.

A mechanistic insight of phytoestrogens used for Rheumatoid arthritis: An evidence-based review.

Assessment of the potential therapeutic benefits offered by naturally occurring phytoestrogens necessitate inspection of their potency and sites of action in impeding the chronic, systemic, autoimmune, joint destructing disorder Rheumatoid arthritis (RA). Possessing structural and functional similarity with human estrogen, phytoestrogen promisingly replaces the use of hormone therapy in eradicating RA symptoms with their anti-inflammatory, anti-oxidative, anti-proliferative, anti-angiogenesis, immunomodulatory, joint protection properties abolishing the harmful side effects of synthetic drugs. Scientific evidences revealed that use of phytoestrogens from different chemical categories including flavonoids, alkaloids, stilbenoids derived from different plant species manifest beneficial effects on RA through various cellular mechanisms including suppression of pro-inflammatory cytokines in particular tumor necrosis factor (TNF-α), interleukin(IL-6) and nuclear factor kappa B (NF-κB) and destructive metalloproteinases, inhibition of oxidative stress, suppressing inflammatory signalling pathways, attenuating osteoclastogenesis ameliorating cartilage degradation and bone erosion. This review summarizes the evidences of different phytoestrogen treatment and their pharmacological mechanisms in both in vitro and in vivo studies along with discussing clinical evaluations in RA patients showing phytoestrogen as a promising agent for RA therapy. Further investigations and more clinical trials are mandatory to clarify the utility of these plant derived compounds in RA prevention and in managing oestrogen deficient diseases in patients.

How does methotrexate suppress inflammation?

Methotrexate remains the most widely used agent for the treatment of rheumatoid arthritis and other chronic inflammatory diseases. Although introduced as a chemotherapeutic agent for the treatment of malignancies, it is clear that, in the doses used, the mechanism of action in the suppression of inflammation differs from simply suppression of purine and pyrimidine metabolism, resulting in inhibition of proliferation. Here we review the proposed mechanisms of action of methotrexate.

[An open-label, multicentric clinical trial to evaluate the efficacy and impact on bone metabolism of recombinant human tumor necrosis factor-α receptor II IgG Fc fusion protein with methotrexate in active rheumatoid arthritis: 24-week clinical and radiographic results from ReABLE study].

OBJECTIVE: To evaluate the efficacy, radiographic changes and safety of the combination of recombinant human tumor necrosis factor-α receptor II IgG Fc fusion protein (rhTNFR:Fc) and methotrexate (MTX) in patients with rheumatoid arthritis (RA). METHODS: 30 RA patients were treated with rhTNFR:Fc (25 mg subcutaneously twice weekly) and oral MTX (up to 15 mg weekly) in an open-label manner. Clinical response was assessed by American College of Rheumatology (ACR) criteria and Disease Activity Score in 28 joints (DAS28). Radiographs of hands and wrist were assessed by the modified Sharp score. RESULTS: At Week 24, ACR20, ACR50 and ACR70 responses were achieved by 90%, 76.67% and 46.67% respectively. At Week 24, the mean DAS28 was 3.65 ± 1.26 versus 6.41 ± 0.61 at baseline (P < 0.001). And 20% patients achieved remission and 16.67% patients had a low disease activity. At week 24, EULAR good and moderate responses were attained by 36.67% and 60% respectively. Similarly, Health Assessment Questionnaire (HAQ) improved significantly, declining from 1.12 at baseline to 0.36 at week 24 (P < 0.001). No radiographic progression (based on change of total Sharp score) was found in 27 cases. Adverse events were mild. CONCLUSION: rhTNFR:Fc in combination with MTX shows an excellent efficacy of reduced disease activity, improved function and slowed radiographic progression through 24 weeks. A combination therapy for 24 weeks can lead to disease remission and an inhibition of radiographic progression. Further study is warranted.

Mechanisms of action of hydroxychloroquine and chloroquine: implications for rheumatology.

Despite widespread clinical use of antimalarial drugs such as hydroxychloroquine and chloroquine in the treatment of rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and other inflammatory rheumatic diseases, insights into the mechanism of action of these drugs are still emerging. Hydroxychloroquine and chloroquine are weak bases and have a characteristic 'deep' volume of distribution and a half-life of around 50 days. These drugs interfere with lysosomal activity and autophagy, interact with membrane stability and alter signalling pathways and transcriptional activity, which can result in inhibition of cytokine production and modulation of certain co-stimulatory molecules. These modes of action, together with the drug's chemical properties, might explain the clinical efficacy and well-known adverse effects (such as retinopathy) of these drugs. The unknown dose-response relationships of these drugs and the lack of definitions of the minimum dose needed for clinical efficacy and what doses are toxic pose challenges to clinical practice. Further challenges include patient non-adherence and possible context-dependent variations in blood drug levels. Available mechanistic data give insights into the immunomodulatory potency of hydroxychloroquine and provide the rationale to search for more potent and/or selective inhibitors.

Recent advances in the opioid mu receptor based pharmacotherapy for rheumatoid arthritis.

INTRODUCTION: Opioids are used for severe forms of acute and cancer pain. Over the last years, their potential use in patients with noncancer pain such as those with rheumatoid arthritis (RA) has been postulated. A recent population-based comparative study showed that chronic opioid use was 12% vs. 4% among RA and non-RA patients, respectively. Another study showed an increase from 7.4% to 16.9% (2002 to 2015). In general, there has been an increasing tendency to use opioids in recent years. AREAS COVERED: The authors have performed an extensive literature search using PubMed for articles including noncancer pain and the use of the mu opioid receptor (MOR) agonists in patients with RA. EXPERT OPINION: Data is not sufficient to support opioid use for the treatment of chronic pain in patients with RA. Data is scarce and inconclusive. Rheumatologists should think and ponder the question: Why is this patient in pain? Differential diagnosis should include a disease flare, degenerative changes of the musculoskeletal system, and fibromyalgia. And while there are new strategies for opioid administration currently being researched, unfortunately, they are far from being applied to human subjects in the everyday clinical setting, and are still being evaluated at an experimental level. CNS: Central nervous system; DORs: delta opioid receptor agonists; GI: Gastrointestinal; GPCRs: G protein-coupled receptors; IL: Interleukin; JAK: Janus kinase; KORs: kappa opioid receptor agonists; MCPs: Metacarpophalangeal joints; MORs: Mu opioid receptor agonists; MTPs: Metatarsophalangeal joints; NSAIDs: Non-steroidal anti-inflammatory drugsOA: Osteoarthritis; ORs: Opioid receptors; PD: Pharmacodynamic; PIPs: Proximal interphalangeal joints; PK: Pharmacokinetic; PNS: Peripheral nervous system; RA: Rheumatoid arthritis; RGS: Regulator of G protein signaling; SSRIs: Selective serotonin reuptake inhibitors; TNF: Tumor necrosis factor.

Use of TNF Inhibitors in Rheumatoid Arthritis and Implications for the Periodontal Status: For the Benefit of Both?

The inflammatory diseases rheumatoid arthritis (RA) and periodontitis show similarities in misbalances of cytokine levels, such as tumor necrosis factor-α (TNF-α). RA has been treated for two decades with TNF inhibitors which are effective by blocking TNF's destructive action. Since RA and periodontitis show similarities in high levels of TNF, the periodontal status of RA patients may improve with the use of anti-TNF therapy. To assess this, a systematic review with special emphasis on duration of therapy was performed to evaluate the effect of anti-TNF-α treatment on the periodontal status of RA patients. Overall, studies showed an improvement in periodontal health with anti-TNF therapy. When analyzed over time (6 weeks to 9 months), it became apparent that initial improvements concerned bleeding on probing (BOP) and gingival index (GI) after therapy duration of 6 weeks. Periodontitis parameters that improved after prolonged treatment were: probing pocket depth (PPD) after 3 months and clinical attachment level (CAL) after 6 months. In conclusion, this systematic review reveals that anti-TNF treatment is therefore not only beneficial for rheumatic joints but also for the gums of rheumatoid arthritis patients. We propose that the sequential tissue recovery due to anti-TNF therapy progresses as follows: 1. block of diapedesis by lowering vessel permeability, 2 fewer leukocytes in the inflamed tissue, and 3. reduced proteolytic activity and subsequent repair of collagen fiber functionality and normalization of osteoclast activity. Clinically, this could lead to a decrease in bleeding on probing and ultimately in an improved clinical attachment level.

Therapeutics on the clock: Circadian medicine in the treatment of chronic inflammatory diseases.

The circadian clock is a collection of endogenous oscillators with a periodicity of ~ 24 h. Recently, our understanding of circadian rhythms and their regulation at genomic and physiologic scales has grown significantly. Knowledge of the circadian influence on biological processes has provided new possibilities for novel pharmacological strategies. Directly targeting the biological clock or its downstream targets, and/or using timing as a variable in drug therapy are now important pharmacological considerations. The circadian machinery mediates many aspects of the inflammatory response and, reciprocally, an inflammatory environment can disrupt circadian rhythms. Therefore, intense interest exists in leveraging circadian biology as a means to treat chronic inflammatory diseases such as sepsis, asthma, rheumatoid arthritis, osteoarthritis, and cardiovascular disease, which all display some type of circadian signature. The purpose of this review is to evaluate the crosstalk between circadian rhythms, inflammatory diseases, and their pharmacological treatment. Evidence suggests that carefully rationalized application of chronotherapy strategies - alone or in combination with small molecule modulators of circadian clock components - can improve efficacy and reduce toxicity, thus warranting further investigation and use.

[Progress of research in osteoarthritis. Pharmacological effects of hyaluronan].

Hyaluronan of high molecular weight is now widely used by intraarticular injection into knee joints in patients with osteoarthritis and rheumatoid arthritis. Proinflammatory cytokines and matrix degradation products (matrikines) increased in osteoarthritic and rheumatoid arthritic joints induce catabolic enzymes such as collagenase and aggrecanase that cause cartilage degradation. The recent studies have shown that hyaluronan inhibits the catabolic actions by cytokines and matrikines via its cell surface receptors. This paper describes the chondroprotective effects of hyaluronan on osteoarthritis and rheumatoid arthritis.

Evaluation of the efficacy and safety of sarilumab combination therapy in patients with rheumatoid arthritis with inadequate response to conventional disease-modifying antirheumatic drugs or tumour necrosis factor α inhibitors: systematic literature review and network meta-analyses.

Objective: To compare efficacy and safety of subcutaneous sarilumab 200 mg and 150 mg every 2 weeks plus conventional synthetic disease-modifying antirheumatic drugs (+csDMARDs) versus other targeted DMARDs+csDMARDs and placebo+csDMARDs, in inadequate responders to csDMARDs (csDMARD-IR) or tumour necrosis factor α inhibitors (TNFi-IR). Methods: Systematic literature review and network meta-analyses (NMA) conducted on 24 week efficacy and safety outcomes: Health Assessment Questionnaire Disability Index, modified total sharp score (mTSS, including 52 weeks), American College of Rheumatology (ACR) 20/50/70, European League Against Rheumatism Disease Activity Score 28-joint count erythrocyte sedimentation rate (DAS28)<2.6; serious infections/serious adverse events (including 52 weeks). Results: 53 trials were selected for NMA. csDMARD-IR: Sarilumab 200 mg+csDMARDs and 150 mg+csDMARDs were superior versus placebo+csDMARDs on all outcomes. Against most targeted DMARDs, sarilumab 200 mg showed no statistically significant differences, except superiority to baricitinib 2 mg, tofacitinib and certolizumab on 24 week mTSS. Sarilumab 150 mg was similar to all targeted DMARDs. TNFi-IR: Sarilumab 200 mg was similar to abatacept, golimumab, tocilizumab 4 mg and 8 mg/kg intravenously and rituximab on ACR20/50/70, superior to baricitinib 2 mg on ACR50 and DAS28<2.6 and to abatacept, golimumab, tocilizumab 4 mg/kg intravenously and rituximab on DAS28<2.6. Sarilumab 150 mg was similar to targeted DMARDs but superior to baricitinib 2 mg and rituximab on DAS28<2.6 and inferior to tocilizumab 8 mg on ACR20 and DAS28<2.6. Serious adverse events, including serious infections, appeared similar for sarilumab versus comparators. Conclusions: Results suggest that in csDMARD-IR and TNFi-IR (a smaller network), sarilumab+csDMARD had superior efficacy and similar safety versus placebo+csDMARDs and at least similar efficacy and safety versus other targeted DMARDs+csDMARDs.

The importance of inhibition of a catabolic pathway of methotrexate metabolism in its efficacy for rheumatoid arthritis.

Methotrexate (MTX), an antifolate, is the anchor drug for the treatment of rheumatoid arthritis (RA). It is inexpensive, effective, and generally safe. When clinical response is inadequate, biological therapies are commonly used in combination with MTX. However, biological agents have safety concerns (i.e. infections, malignancy) and the addition of a biologic agent is expensive, making strategies to improve MTX efficacy important. Inhibition of pathways of folate metabolism involving purine metabolism by MTX, have been traditionally emphasized as important in MTX efficacy. However, inhibition MTX catabolism may also be important. MTX is irreversibly hydroxylated to form 7-hydroxy methotrexate (7-OH-MTX) by aldehyde oxidase (EC 1.2.3.1) (AOX). Catabolism of MTX to 7-OH-MTX is the first metabolic process imposed on an oral dose of MTX and will alter subsequent interactions of MTX with other enzymes. 7-OH-MTX is less potent than MTX in the treatment of rat adjuvant arthritis. RA patients with a low capacity to catabolize MTX to 7-OH-MTX do better clinically than individuals who are rapid formers of 7-OH-MTX. Therefore, altering the catabolism of MTX may be an innovative way to improve MTX efficacy. Raloxifene is a FDA-approved therapy for postmenopausal osteoporosis and for the reduction of invasive breast cancers but has no known activity in RA. Raloxifene is a potent inhibitor of human liver AOX. Postmenopausal women with RA frequently have low bone mineral density and would be candidates for raloxifene and MTX combination therapy. The effect of raloxifene on MTX metabolism has never been studied. Our hypothesis is that in postmenopausal women with RA and osteoporosis treated with MTX and raloxifene, the inhibition of AOX with resultant decreased formation of 7-OH MTX; will increase MTX levels and improve MTX efficacy. This hypothesis could be studied in an open-label, proof of concept clinical study in individuals before and after the addition of raloxifene. Red blood cell MTX and 7-OH-MTX levels and RA disease activity (DAS28) would be measured. In possible future studies, there are dietary substances, as supplements, (e.g. epigallocatechin gallate in green tea and resveratrol) which inhibit human liver AOX which could be evaluated.

Introducing Patterns of Variability for Overcoming Compensatory Adaptation of the Immune System to Immunomodulatory Agents: A Novel Method for Improving Clinical Response to Anti-TNF Therapies.

Primary lack of response and secondary loss of response (LOR) are major obstacles to the use of anti-tumor necrosis factor (TNF)-based therapies in patients with rheumatoid arthritis or inflammatory bowel disease. Here, we review the mechanisms and methods for predicting LOR and the currently used methods for overcoming the ineffectiveness of anti-TNFs. The complex functions of TNF and anti-TNF antibodies, which can promote both pro- or anti-inflammatory actions, and the factors that affect the induction of immune tolerance to their effects are presented. The lack of rules and the continuous dynamics of the immune processes partly underlie the unpredictability of the response to anti-TNFs. Variability is inherent to biological systems, including immune processes, and intra/inter-patient variability has been described in the response to drugs. This variability is viewed as a compensatory adaptation mechanism of the immune system in response to drugs and may contribute to treatment LOR. Dose reductions and drug holidays have been tested in patients treated with anti-TNFs. Regular dose-based regimens may be incompatible with physiological variability, further contributing to treatment inefficacy. We present the concept of overcoming immune system adaptation to anti-TNFs by introducing patient-tailored patterns of variability to treatment regimens.