Mode of action of abatacept in rheumatoid arthritis patients having failed tumour necrosis factor blockade: a histological, gene expression and dynamic magnetic resonance imaging pilot study

B cells in rheumatoid arthritis: from pathogenic players to disease biomarkers

The therapeutic benefit of depleting B cells in rheumatoid arthritis (RA) has refocused attention on B cells with increasing awareness on their role in autoimmunity and their function beyond autoantibody production. The rapid increase in our comprehension of B-cell pathobiology is progressively opening novel perspectives in the area of B cell-targeted therapies with the expectation to define more specific approaches able to preserve the homeostasis of the humoral response while disrupting the pathogenic components. In parallel, B-cell activity in RA is starting to be explored in its clinical value, in search of novel biomarkers embedded in the pathogenic process that could help classifying the disease and predicting its heterogeneous outcome beyond inflammation dynamics. In this review, we summarize current knowledge on the multiple roles that B cells play in several aspects of RA. We also analyze their distribution and potential function in different anatomic compartments with specific reference to the main sites in which the disease may be sustained and exert its detrimental effects: the systemic circulation, synovium, bone marrow, and draining lymph nodes. We also highlight novel data encouraging further research in the field of biomarkers related to B cells and their regulatory factors.

Phase III, multicenter, open-label, long-term study of the safety of abatacept in Japanese patients with rheumatoid arthritis and an inadequate response to conventional or biologic disease-modifying antirheumatic drugs

Objectives

To examine the long-term safety of intravenous (IV) abatacept treatment in Japanese patients with rheumatoid arthritis (RA) and an inadequate response to methotrexate (MTX) or other conventional or biologic disease-modifying antirheumatic drugs.

Methods

This Phase III, open-label, long-term study (NCT00484289) comprised Japanese patients with RA who had completed abatacept Phase I or Phase II studies, and new patients intolerant to MTX. Patients from Phase I and Phase II studies received a weight-tiered dosing equivalent of 10 mg/kg abatacept, with MTX at doses up to 8 mg/week; newly enrolled patients received weight-tiered 10 mg/kg abatacept monotherapy. Safety and efficacy were assessed.

Results

A total of 217 patients (Phase I, n = 13; Phase II, n = 178; newly enrolled, n = 26) were treated with IV abatacept for a mean of 3 years. Serious adverse events occurred in 67/217 (30.9%) patients. Most adverse events were mild or moderate. For all cohorts combined, American College of Rheumatology 20% response rates ranged from 61.3 to 81.8% for as-observed and last observation carried forward analyses over 192 weeks. Following initial response, clinical and functional outcomes were maintained for up to 3 years.

Conclusions

In Japanese patients with RA, IV abatacept with and without background MTX showed tolerable safety and sustained efficacy over 3 years.

Update on the use of abatacept for the treatment of rheumatoid arthritis

Abatacept is approved for the treatment of moderate-to-severe active rheumatoid arthritis (RA) patients with inadequate response to one or more disease-modifying antirheumatic drugs (DMARDs), including methotrexate or a TNF antagonist, and can be used either as monotherapy or concomitantly with nonbiologic DMARDs. It can be administered either intravenously or subcutaneously. It has demonstrated to improve signs and symptoms of RA, physical function and health-related quality of life, and it inhibits radiographic progression of structural damage across a wide range of early and long-standing RA populations. The safety profile appears good and close to RA patients treated with nonbiologic DMARDs. Meta-analysis and real-world studies support these findings. This article reviews published data on clinical and radiographic efficacy as well as the safety of this drug, incorporating recent relevant information reported at scientific meetings.

Abatacept reduces levels of switched memory B cells, autoantibodies, and immunoglobulins in patients with rheumatoid arthritis

OBJECTIVE

Abatacept (ABA) is a chimeric molecule, able to block the CD28-mediated costimulatory pathway. To evaluate the hypothesis that, through this mechanism of action, ABA may down-modulate the immune responses of B lymphocytes in rheumatoid arthritis (RA), we investigated the serum levels of immunoglobulins (Ig), free light chains (FLC), anticitrullinated protein antibodies (ACPA), and rheumatoid factor (RF), as well as the number of B lymphocytes differentiated into post-switch memory cells in patients treated with ABA.

METHODS

The serum levels of Ig, FLC, different ACPA, RF isotypes, and the B cell phenotype were longitudinally evaluated in 30 patients with RA treated with ABA.

RESULTS

At baseline, the proportion of total and post-switch memory B cells was lower in RA than in healthy individuals. After 6 months of ABA treatment we observed significant reductions of serum levels of IgG, IgA, and IgM, as well as FLC, with a normalization in many patients who had initially abnormal values. A significant reduction of the titers of IgG- and IgA-ACPA, as well as of IgM-, IgA-, and IgG-RF was also observed. A decrease of autoantibodies below the upper limits of normal values was found in 2 of 26 patients (8%) initially seropositive for IgG-ACPA, 1 of 14 (7%) for IgA-ACPA, 5 of 22 (23%) for IgM-RF, 7 of 22 (30%) for IgA-RF, and 5 of 16 (31%) for IgG-RF. After treatment, the proportion of circulating post-switch memory B cells was also further significantly decreased.

CONCLUSION

ABA treatment in patients with RA can reduce signs of polyclonal B cell activation, inducing a trend toward normalization of serum levels of different classes of Ig and of FLC, decreasing titers of ACPA and RF, and percentages of post-switch memory B cells.

Abatacept: a review of its use in the management of rheumatoid arthritis

The biological disease-modifying antirheumatic drug abatacept (Orencia) has a novel mechanism of action; its activity is mediated via the selective modulation of T cell co-stimulation. This article reviews the clinical efficacy and tolerability of intravenous and subcutaneous abatacept in patients with rheumatoid arthritis (RA) and intravenous abatacept in patients with juvenile idiopathic arthritis (JIA), as well as summarizing its pharmacological properties. In patients with RA, the beneficial effects of intravenous or subcutaneous abatacept on signs and symptoms, disease activity, the progression of structural damage, physical function and/or health-related quality of life were seen in a number of well-designed trials, including in methotrexate-naive patients with early RA and poor prognostic factors and in patients with established RA and an inadequate response to either methotrexate or anti-tumour necrosis factor therapy. Subcutaneous abatacept plus methotrexate was also noninferior to subcutaneous adalimumab plus methotrexate in patients with active RA who were naive to biological therapy and had an inadequate response to methotrexate. In paediatric patients with JIA, intravenous abatacept improved signs and symptoms and delayed the time to flare. Abatacept was generally well tolerated in RA and JIA and was associated with low rates of immunogenicity. In conclusion, abatacept is an important option for use in the treatment of RA and JIA.

Non-tumor necrosis factor-based biologic therapies for rheumatoid arthritis: present, future, and insights into pathogenesis

The way rheumatoid arthritis is treated has changed dramatically with the introduction of anti-tumor necrosis factor (anti-TNF) biologics. Nevertheless, many patients still have less than adequate control of their disease activity even with these therapeutic regimens, and current knowledge fails to explain all the data already gathered. There is now a wide range of drugs from different classes of biologic disease-modifying anti-rheumatic drugs available (and soon this number will increase significantly), that provides the opportunity to address each patient as a particular case and thereby optimize medical intervention. Currently available biologics for the treatment of rheumatoid arthritis apart from anti-TNF-based therapies are reviewed, along with an analysis of the new insights they provide into the pathogenesis of the disease and a discussion of future prospects in the area.

New learnings on the pathophysiology of RA from synovial biopsies

PURPOSE OF REVIEW

To critically appraise the literature related to the pathophysiology of rheumatoid arthritis (RA) focusing on the contribution of synovial tissue pathology (synovitis) in determining diverse clinical outcome/therapeutic response.

RECENT FINDINGS

RA synovitis is highly heterogeneous with diverse cellular and molecular signatures (pathotypes) emerging as potential taxonomic classifiers of disease phenotypes.The challenge is to understand mechanistically the sophisticated interplay between systemic disease 'initiators' and joint-specific 'localizing/perpetuating' factors leading to disparate coupling of inflammation/tissue-destructive pathways and disease outcome. Synovial tissue analysis has been instrumental in enhancing understanding of R0A pathogenesis and developing targeted DMARD-biologic therapies. The next step is to elucidate the relationship of different synovial pathotypes/molecular signatures with therapeutic response/resistance in randomized clinical trials in order to develop effective therapies for 'resistant' patients. The development of ultrasound-guided synovial biopsy as a rapid, safe and well tolerated procedure that enables synovial tissue collection from most joints/patients will facilitate such studies.

SUMMARY

RA is a heterogeneous clinical and pathobiological entity. Specific pathways within synovial tissues are emerging as associated with diverse clinical evolution and therapeutic response/resistance that, if confirmed in randomized clinical trials, may lead to the development of synovial tissue analysis as a potential clinical tool for patient stratification.

CTLA4-Ig (abatacept) therapy modulates T cell effector functions in autoantibody-positive rheumatoid arthritis patients

Background

Rheumatoid arthritis is a chronic inflammatory disease with a strong MHC class II component and where many patients develop characteristic autoantibodies towards the noncoding amino acid citrulline. Such anti-citrullinated protein antibodies (ACPA) have recently been put forward as an independent predictive factor for treatment response by co-stimulation blockade by CTLA4-Ig (abatacept). We have performed a mechanism of action study to dissect T cell functionality in RA patients with long-standing disease undergoing abatacept treatment and the influence of ACPA status.

Results

Peripheral blood samples were collected from RA patients as they started CTLA4-Ig treatment and 3 and 6 months later. A general decrease of regulatory T cell subsets was observed in the cohort. Additionally within the ACPA-positive group significant down-regulation of all key T cell effector subsets including Th1, Th2, and Th17 was observed by analyzing cytokines by intracellular flow cytometry and in cell culture supernatants.

RA synovial fluid samples were cultured in vitro in the presence or absence of CTLA4-Ig (abatacept). T cell cytokine production was diminished, but without increasing the functional capacity of CD4+CD25hi regulatory T cells as previously demonstrated in the context of TNF-blockade and anti-IL6R therapy.

Conclusions

Our immunological study of T cell functionality in RA patients, both ACPA-positive and ACPA-negative, starting biological therapy with the co-stimulation blockade abatacept (CTLA4-Ig) supports the recently published registry study implicating ACPA seropositivity as an independent predictive factor to treatment response as we observed the most striking effect on T cell subset modulation in ACPA-positive patients. These data further support the notion of RA as a disease with several sub-entities, where the ACPA-positive fraction represents a classical HLA-associated autoimmune disorder while ACPA-negative patients may have other driving forces apart from classical adaptive immune responses.

CTLA-4Ig immunotherapy of obesity-induced insulin resistance by manipulation of macrophage polarization in adipose tissues

It has been established that obesity alters the metabolic and endocrine function of adipose tissue and, together with accumulation of adipose tissue macrophages, contributes to insulin resistance. Although numerous studies have reported that shifting the polarization of macrophages from M1 to M2 can alleviate adipose tissue inflammation, manipulation of macrophage polarization has not been considered as a specific therapy. Here, we determined whether cytotoxic T-lymphocyte-associated antigen-4IgG1 (CTLA-4Ig) can ameliorate insulin resistance by induction of macrophages from proinflammatory M1 to anti-inflammatory M2 polarization in the adipose tissues of high fat diet-induced insulin-resistant mice. CTLA4-Ig treatment prevented insulin resistance by changing gene expression to M2 polarization, which increased the levels of arginase 1. Furthermore, flow cytometric analysis confirmed the alteration of polarization from CD11c (M1)- to CD206 (M2)-positive cells. Concomitantly, CTLA-4Ig treatment resulted in weight reductions of epididymal and subcutaneous adipose tissues, which may be closely related to overexpression of apoptosis inhibitors in macrophages. Moreover, proinflammatory cytokine and chemokine levels decreased significantly. In contrast, CCAAT enhancer binding protein α, peroxisome proliferator-activated receptor γ, and adiponectin expression increased significantly in subcutaneous adipose tissue. This novel mechanism of CTLA-4lg immunotherapy may lead to an ideal anti-obesity/inflammation/insulin resistance agent.

WITHDRAWN: Abatacept as a first-line biological therapy

The Publisher regrets that this article is an accidental duplication of an article that has already been published, http://dx.doi.org/10.1016/j.autrev.2013.06.008. The duplicate article has therefore been withdrawn.

Modulating the co-stimulatory signal for T cell activation in rheumatoid arthritis: could it be the first step of the treatment?

Advances in our understanding of the key mediators of chronic inflammation and tissue damage in rheumatoid arthritis (RA) have fostered the development of targeted therapies and greatly expanded the available treatment options. Abatacept, a soluble human fusion protein that selectively modulates the co-stimulatory signal required for full T-cell activation, is approved for the treatment of moderate to severe RA in the United States, Canada, and the European Union. This review summarises the data on efficacy (disease activity, quality of life, prevention of structural damage) and safety from randomised clinical trials of abatacept plus methotrexate in patients with: i) active RA and an inadequate response to methotrexate who are naïve to biological disease-modifying anti-rheumatic drugs; and ii) methotrexate-naïve early RA with poor prognostic factors. Novel imaging outcomes and biological changes induced by abatacept treatment are also briefly reviewed. Optimal use of abatacept as a first-line biological therapy is discussed in light of the current recommendations and guidelines.

Safety of abatacept administered intravenously in treatment of rheumatoid arthritis: integrated analyses of up to 8 years of treatment from the abatacept clinical trial program

OBJECTIVE

To assess the overall safety, including rare events, of intravenous (IV) abatacept treatment in rheumatoid arthritis (RA).

METHODS

Data from 8 clinical trials of IV abatacept in RA were pooled. Safety events were assessed during the short-term (duration ≤ 12 months) and cumulative (short-term plus longterm extensions) abatacept treatment periods. Incidence rates per 100 patient-years were calculated. Standardized incidence ratios (SIR) for hospitalized infections and malignancies were compared with external RA cohorts and, for malignancies, with the US general population.

RESULTS

There were 3173 IV abatacept-treated patients with 2331 patient-years of exposure in the short-term periods, and 4149 IV abatacept-treated patients with 12,132 patient-years of exposure in the cumulative period. Incidence rates for serious infections were low and consistent over time (3.68 for abatacept vs 2.60 for placebo during the short-term, and 2.87 for abatacept during the cumulative period). Hospitalized infections were generally similar to external RA patient cohorts and were consistent over time. Incidence rates of malignancies were similar for abatacept- and placebo-treated patients during the short-term period (0.73 vs 0.59) and remained low during the abatacept cumulative period (0.73). SIR of some tissue-specific malignancies (e.g., colorectal and breast) in the cumulative period tended to be lower, while others (lymphoma and lung) tended to be higher, compared with the general population; however, incidence rates were comparable with RA cohorts. Autoimmune events were rare and infusion reactions uncommon.

CONCLUSION

Longterm safety of IV abatacept was consistent with the short-term, with no unexpected events and low incidence rates of serious infections, malignancies, and autoimmune events.

Therapeutic effect of cytotoxic T lymphocyte antigen 4/immunoglobulin on a murine model of primary biliary cirrhosis

Collectively, the data in both humans and murine models of human primary biliary cirrhosis (PBC) suggest that activated T cells, particularly CD8 T cells, play a critical role in biliary cell destruction. Under physiological conditions, T-cell activation involves two critical signals that involve the major histocompatibility complex and a set of costimulatory molecules, which include a receptor on T cells termed cytotoxic T lymphocyte antigen 4 (CTLA-4). Germane to the studies reported herein, signaling by CTLA-4 has the potential to modulate costimulation and induce inhibitory signals. In this study, we have taken advantage of our well-defined murine model of PBC, in which mice are immunized with 2-octynoic acid coupled to bovine serum albumin (2OA-BSA), leading to the production of high-titer antimitochondrial autoantibodies (AMAs) and portal cellular infiltrates. To investigate the potential of CTLA-4-Ig (immunoglobulin) as an immunotherapeutic agent, we treated mice both before and after induction of autoimmune cholangitis. First, we demonstrate that CTLA-4-Ig treatment, begun 1 day before 2OA-BSA immunization, completely inhibits the manifestations of cholangitis, including AMA production, intrahepatic T-cell infiltrates, and bile duct damage. However, and more critically, treatment with CTLA-4-Ig, initiated after the development of autoimmune cholangitis in previously immunized mice, also resulted in significant therapeutic benefit, including reduced intrahepatic T-cell infiltrates and biliary cell damage, although AMA levels were not altered.

CONCLUSION

These data suggest that an optimized regimen with CTLA-4-Ig has the potential to serve as an investigative therapeutic tool in patients with PBC.

Advances in CTLA-4-Ig-mediated modulation of inflammatory cell and immune response activation in rheumatoid arthritis

Rheumatoid arthritis (RA) is a multifactorial and polygenic immune-mediated disease, the pathogenesis of which involves different cell types. T and B lymphocytes, macrophages, endothelial cells, fibroblasts and osteoclasts have all been implicated in mediating the production of autoantibodies, proinflammatory cytokines and ultimately bone erosions. Cytotoxic T lymphocyte-associated antigen 4 immunoglobulin fusion protein (CTLA-4-Ig, abatacept) is a unique biologic agent targeting the co-stimulatory molecules CD80/CD86, and is indicated for the treatment of moderate-to-severe RA in patients who have had an inadequate response to one or more disease-modifying anti-rheumatic drugs, including methotrexate or anti-tumor necrosis factor agents. There is a growing body of evidence that, through selective modulation of the CD80/CD86 co-stimulatory molecules expressed by a variety of activated cell types, CTLA-4-Ig may inhibit the pathogenic RA process at several levels, both directly and indirectly. Here, we provide an overview of recent mechanistic studies of the action of CTLA-4-Ig on different cell types involved in mediating inflammation and joint damage in RA.

Dendritic cell migration through the lymphatic vasculature to lymph nodes

The mobilization of antigen-presenting dendritic cells (DCs) from peripheral tissues to draining lymph nodes drives the initiation of adaptive immune responses. Recent advances have been made in understanding how and where DCs enter the lymphatic vasculature and what mechanisms control this process. In this chapter, we highlight these advances. Delineating DC-lymphatic vessel interactions is critical for our fundamental understanding of DC trafficking in states of health and disease and for efforts to manipulate DC mobilization for immunotherapy and vaccination.

[Personalized medicine for rheumatoid arthritis : serological and clinical patient profiles to optimize B and T cell targeted therapy]

Nowadays B and T-cell directed biologics in addition to TNF inhibitors are established as effective and safe treatment options for rheumatoid arthritis. As shown by the approval of rituximab for the treatment of systemic vasculitis, these drugs can also be useful for the treatment of other systemic autoimmune diseases; however, to optimize therapeutic strategies, predictive factors for treatment response as well as a good characterized safety profile are essential. So far implementation of real personalized medicine is not feasible in the field of rheumatology, but first biomarkers have already been identified and provide promising results. In this context, it has been shown that a B-cell directed therapy with rituximab is more effective in seropositive patients with rheumatoid arthritis. In addition, characterization of the cytokine milieu as well as of circulating and tissue infiltrating B and T-cell subsets might be useful for prediction of treatment response in the near future.

When is switching warranted among biologic therapies in rheumatoid arthritis?

Switching among biologic therapies is common practice in patients with rheumatoid arthritis who have an inadequate response or intolerable adverse events. Evidence from observational studies and association guidelines supports the use of sequential biologic therapy for these reasons. Owing to recent economic pressures on healthcare budgets, patients with rheumatoid arthritis who are well controlled on and tolerant of their current biologic therapy may be switched to alternative biologics, despite limited evidence supporting this practice. Clinical research and experience suggest that TNF antagonists are not interchangeable, as meaningful differences have been observed in their efficacy and safety profiles. Additional research is needed to assess the risk:benefit ratio of specific sequences of biologic therapies and the validity of switching biologic therapies for nonclinical purposes.

Impact of intravenous abatacept on synovitis, osteitis and structural damage in patients with rheumatoid arthritis and an inadequate response to methotrexate: the ASSET randomised controlled trial

Objectives

This randomised, double-blind, placebo-controlled phase IIIb study evaluated the impact of abatacept on MRI pathology as a primary outcome in methotrexate (MTX)-refractory patients with rheumatoid arthritis.

Methods

Patients received intravenous abatacept (∼10 mg/kg) or placebo, on background MTX, for 4 months, followed by an 8-month open-label extension (OLE; all patients received abatacept plus MTX). Patients had 1.5T MRI with intravenous contrast at baseline, Months 4 and 12; wrist synovitis (three locations assessed), and wrist and hand (15 and eight locations assessed, respectively) osteitis and erosion were scored using OMERACT-RAMRIS.

Results

26/27 abatacept- and 23/23 placebo-randomised patients completed Month 4 and entered the OLE; 26 and 21 completed Month 12. The primary endpoint was not achieved; mean change (SD) from baseline in synovitis was −0.44 (1.47) for abatacept versus 0.52 (1.38) for placebo (p=0.103) at Month 4. For mean change in synovitis adjusted for baseline score (sensitivity analysis), the difference between groups was −0.69, p=0.078. Adjusted mean changes (SE) in osteitis and erosion were −1.94 (0.86) and 0.45 (0.43) for abatacept, and 1.54 (0.90) and 0.95 (0.45) for placebo. Further MRI improvements were observed up to Month 12 for abatacept and from Months 4 to 12 for placebo-treated patients switched to abatacept at Month 4. Clinical efficacy was shown with abatacept and sustained to Month 12.

Conclusions

Despite small patient numbers, MRI detected structural and synovial benefit, sustained to Month 12 in abatacept+MTX-treated patients, and improvements in structural and inflammatory outcomes for placebo+MTX-treated patients following addition of abatacept.

Clinical trial registration

Clinicaltrials.gov NCT00420199.

Sphingosine kinase and sphingosine-1-phosphate receptors: novel therapeutic targets of rheumatoid arthritis?

Rheumatoid arthritis (RA) is a chronic, destructive, autoimmune joint disease characterized by elevated levels of proinflammatory cytokine production. Sphingosine kinase (SphK) phosphorylates sphingosine into sphingosine-1-phosphate. Synovial fluid of RA patients exhibits significantly higher levels of S1P than their non-inflammatory osteoarthritis counterparts. SphK blockade suppresses cytokines and MMP-9 release in RA peripheral blood mononuclear cells. In addition, downregulation of SphK1 either through a specific siRNA approach or transgenic human TNF-α SphK1-deficient mice (hTNF-α/SphK1(-/-)) exhibit significantly less synovial inflammation and joint pathology. By contrast, SphK2 modulation leads to disease exacerbation. These results clearly demonstrate that such anti- and proinflammatory potential of SphK1/2 modulation may alter the outcome in RA synovitis and raises the possibility that drugs that specifically target SphK1 activity may play a beneficial role in the treatment of RA and other autoimmune rheumatic diseases.

Abatacept use in rheumatoid arthritis: evidence review and recommendations

OBJECTIVE

To review the clinical evidence on abatacept and to formulate recommendations in order to clear up points related to its use in rheumatology.

METHOD

An expert panel of rheumatologists objectively summarized the evidence on the mechanism of action, practicalities, effectiveness and safety of abatacept, and formulated recommendations following a literature review. The level of evidence and degree of recommendation was established.

RESULTS

The document presents 21 statements focused on evidence or recommendations on abatacept (14 evidence summaries and 9 recommendations). The level of evidence was 2b or higher according to the Oxford Centre for Evidence-Based Medicine scale on 14 occasions. The degree of the recommendation was A in two recommendations, C in one, and D in the rest. It was considered important to make recommendations on aspects with lower levels of evidence.

CONCLUSIONS

This is a practical document to supplement the summary of product characteristics.

B effector cells in rheumatoid arthritis and experimental arthritis

Rheumatoid arthritis is a chronic autoimmune immune disease affecting approximately 1% of the population. There has been a renewed interest in the role of B cells in rheumatoid arthritis based on the evidence that B cell depletion therapy is effective in the treatment of disease. This review summarizes the current knowledge of the mechanisms by which B cells contribute to autoimmune arthritis including roles as autoantibody producing cells, antigen-presenting cells, cytokine producing cells, and regulatory cells.

Current understanding of rheumatoid arthritis therapy

Progress in understanding the cellular and molecular mechanisms of rheumatoid arthritis (RA), together with the availability of new therapies, has changed the way we think about RA. The paradigm shift in RA therapy has been from controlling symptoms to controlling the disease process with the abrogation of inflammation. Challenges that are still unresolved include the issues in disease prevention, treatment specificity to restore tolerance, approaches to facilitate tissue repair, and treatment optimization to fit the individual patient's disease phenotype and comorbidity context. This review summarizes the pathogenesis-related rationales for the current therapeutic strategies in RA and for emerging therapies and potential approaches to restoring immune tolerance in RA.

Synovial tissue response to treatment in rheumatoid arthritis

The recognition of the synovial tissue, as the primary target of inflammation in RA, has driven research in this field, not only to clarify the disease pathogenesis but also to evaluate local changes in response to treatment. Special interest has been given to the identification of sensitive synovial biomarkers that could be of help in demonstrating proof of principle in early stages of drug development. Synovial sublining macrophages have been shown to correlate with scores for disease activity in cross-sectional studies. Moreover, decreased disease activity as measured by the disease activity score evaluated in 28 joints (DAS28) after effective treatment, has consistently been associated with a reduction of the number of CD68+ synovial sublining macrophages across different therapies. This observation highlights a possible final common pathway in the mechanism of action of various therapies and supports the notion that macrophages have a central role in RA pathogenesis.

When considering experimental therapies, the study of serial synovial biopsies in relatively small numbers of patients, in the context of proof of principle trials, successfully distinguished between effective and ineffective treatments. This attractive approach can be used during early drug development for screening proposes, supporting which new treatments have higher probability to be beneficial in a large scale clinical trial.

In this paper we review the effects of RA treatments on the synovial tissue, including targeted therapies, with particular attention to their effect on synovial biomarkers.

Fixed drug eruption followed by lichen aureus during abatacept add-on therapy of rheumatoid arthritis

BACKGROUND

Abatacept is a soluble fusion protein approved as add-on drug in rheumatoid arthritis.

MAIN OBSERVATIONS

Here we report the first case of fixed drug eruption followed by lichen aureus due to abatacept in a 67-year-old woman.

CONCLUSION

Fixed drug eruption is an unexpected drug reaction for abatacept, since T-cell activation is inhibited.

Baseline numbers of circulating CD28-negative T cells may predict clinical response to abatacept in patients with rheumatoid arthritis

OBJECTIVE

To evaluate the number of circulating CD28-negative (CD28-) T cells as a predictor of clinical response to abatacept in patients with rheumatoid arthritis (RA).

METHODS

Peripheral blood CD28- T cell subsets were evaluated by flow cytometry at baseline in 32 patients with RA treated with abatacept. Receiver-operator curves were applied to examine the predictive value of T cell populations and to choose the cutoff for the best performance of the test. Remission was defined using the Disease Activity Score 28 based on C-reactive protein.

RESULTS

The overall predictive values of the CD8+CD28- and CD4+CD28- cells for remission after 6 months of abatacept therapy were 0.802 (SE 0.078) and 0.743 (SE 0.089), respectively. Cutoff values of < 87 CD8+CD28- cells/μl and < 28 CD4+CD28- cells/μl had 80.0% sensitivity and 81.8% specificity (Fisher test: p = 0.001), and 60.0% sensitivity and 77.3% specificity (p = 0.043), respectively, for prediction of remission at 6 months. Patients having low baseline numbers of CD8+CD28- T cells had a more than 4-fold higher probability of achieving remission within 6 months than patients with higher levels of these cells.

CONCLUSION

A simple laboratory measure, the baseline number of circulating CD28- T cells, predicted remission after 6 months of abatacept treatment in patients with RA.

Change in CD3 positive T-cell expression in psoriatic arthritis synovium correlates with change in DAS28 and magnetic resonance imaging synovitis scores following initiation of biologic therapy--a single centre, open-label study

INTRODUCTION

With the development of increasing numbers of potential therapeutic agents in inflammatory disease comes the need for effective biomarkers to help screen for drug efficacy and optimal dosing regimens early in the clinical trial process. This need has been recognized by the Outcome Measures in Rheumatology Clinical Trials (OMERACT) group, which has established guidelines for biomarker validation. To seek a candidate synovial biomarker of treatment response in psoriatic arthritis (PsA), we determined whether changes in immunohistochemical markers of synovial inflammation correlate with changes in disease activity scores assessing 28 joints (ΔDAS28) or magnetic resonance imaging synovitis scores (ΔMRI) in patients with PsA treated with a biologic agent.

METHODS

Twenty-five consecutive patients with PsA underwent arthroscopic synovial biopsies and MRI scans of an inflamed knee joint at baseline and 12 weeks after starting treatment with either anakinra (first 10 patients) or etanercept (subsequent 15 patients) in two sequential studies of identical design. DAS28 scores were measured at both time points. Immunohistochemical staining for CD3, CD68 and Factor VIII (FVIII) was performed on synovial samples and scored by digital image analysis (DIA). MRI scans performed at baseline and at 12 weeks were scored for synovitis semi-quantitatively. The ΔDAS28 of the European League Against Rheumatism good response definition (>1.2) was chosen to divide patients into responder and non-responder groups. Differences between groups (Mann Whitney U test) and correlations between ΔDAS28 with change in immunohistochemical and MRI synovitis scores (Spearman's rho test) were calculated.

RESULTS

Paired synovial samples and MRI scans were available for 21 patients (8 anakinra, 13 etanercept) and 23 patients (8 anakinra, 15 etanercept) respectively. Change in CD3 (ΔCD3) and CD68 expression in the synovial sublining layer (ΔCD68sl) was significantly greater in the disease responders compared to non-responders following treatment (P = 0.005 and 0.013 respectively). ΔCD3, but not ΔCD68 or ΔFVIII, correlated with both ΔDAS28 (r = 0.49, P = 0.025) and ΔMRI (r = 0.58, P = 0.009).

CONCLUSIONS

The correlation of ΔCD3 with ΔDAS28 and ΔMRI following biologic treatment in this cohort contributes to the validation of ΔCD3 as a synovial biomarker of disease response in PsA, and supports the further evaluation of ΔCD3 for predictive properties of future clinical outcomes.

Pharmacotherapy: concepts of pathogenesis and emerging treatments. Co-stimulation and T cells as therapeutic targets

Full activation and differentiation of resting T cells into effector T cells requires at least two signals, the first through engagement of the T cell antigen receptor (TCR) by the antigen-major histocompatibility complex (MHC) on antigen-presenting cells (APCs), and the second by engagement of co-stimulatory molecules such as CD28, on T cells by ligands such as CD80/86 on APCs. Effector T cell differentiation is associated with proliferation, secretion of cytokines and expression of additional surface molecules. These inducible structures may have stimulatory (ICOS, OX40 and 4-1BB) or inhibitory (cytotoxic T-lymphocyte antigen (CTLA)-4) potential. To the extent that T cells have a role in particular immune-mediated diseases, interruption of T cell co-stimulation is a potentially worthwhile approach to the treatment of those conditions. This article summarises the experience in treating rheumatological disease by perturbation of T cell co-stimulation, and also describes structures that could be future targets for this type of therapeutic approach.

Comparison of the manual and computer-aided techniques for evaluation of wrist synovitis using dynamic contrast-enhanced MRI on a dedicated scanner

OBJECTIVE

Traditional methods for assessment of synovial inflammation in rheumatoid arthritis such as clinical examination, immunohistology of bioptic samples, scintigraphy, and radiography have several limitations, including lack of sensitivity, need of invasive techniques, and administration of radioactive material. MRI lacks on standardisation and the data are often analysed using laborious, relatively rigid scoring methods.

MATERIALS AND METHODS

This study introduces a standardized computer-aided method for quantitative analysis of MRI of the wrist on a dedicated scanner. Assessment of the synovial inflammation was performed using a semi-automated model-based method in conjunction with patient motion reduction algorithms. Further, the new method was compared with the traditional user-dependent ROI-based technique.

RESULTS

The computer-aided technique generated robust and reproducible results. Application of motion reduction algorithms allowed for significant improvements of the signal to noise ratio, which is especially important in the datasets acquired with low-field scanners.

CONCLUSION

The use of the computer software can be beneficial for diagnostic decision in cross sectional as well as longitudinal MRI examinations of the wrist in rheumatoid arthritis.

Abatacept treatment for rheumatoid arthritis

Significant advances in our understanding of RA and its management have been made in the past decade, resulting in earlier intervention with biologic DMARDs, particularly in patients with evidence of aggressive, erosive disease. Here, one such biologic therapy, the T-cell co-stimulation modulator abatacept, is discussed, exploring clinical evidence published to date on its use in patients with very early arthritis/early RA who are MTX naïve, and in patients with established RA and an inadequate response to MTX or TNF antagonists. Data from relevant clinical trials are overviewed, discussing the clinical efficacy of abatacept in early disease, the clinical outcomes over long-term treatment in different patient populations and the effects of abatacept on structural damage. Findings from integrated safety analyses of abatacept clinical trial data, representing 10 366 patient-years of exposure are described, and clinically important safety events, including serious infections, malignancies and autoimmune events, are highlighted. It is concluded that abatacept represents an effective treatment option with an established safety profile across different patient populations, including patients with both early and erosive RA and those with established disease. Furthermore, efficacy data from studies in patients with early disease suggest that the risk–benefit profile of abatacept may be more favourable when introduced earlier in the treatment paradigm.

[How do T-cells become activated in joints?]

Activated CD4+ T-cells are found in joints of patients with rheumatoid arthritis and are involved in the joint destroying autoimmune response. Besides proinflammatory cytokine production T-cells are indispensable for the activation of B-cells, the so-called T-cell help for B-cells. However, the recognition of autoantigens by T-cells seems of utmost importance for the pathogenesis of rheumatoid arthritis. Selective inhibition of this process is therefore one of the most interesting therapeutic targets for the future.

Decreased circulating CD28-negative T cells in patients with rheumatoid arthritis treated with abatacept are correlated with clinical response

OBJECTIVE

To verify the hypothesis that blockade of CD28 costimulation by treatment with abatacept in patients with rheumatoid arthritis (RA) might induce a reduction in the number of CD28- T cells, as well as other effector T cell populations. We evaluated whether these variations correlate with clinical response.

METHODS

Peripheral blood T cell subsets were longitudinally evaluated by flow cytometry through the analysis of CD28, CD45RA, and CCR7 expression in 16 patients with RA who were treated with abatacept.

RESULTS

After 48 weeks of treatment, the proportion and the absolute number of circulating CD8+CD28- T cells decreased (p = 0.008, p = 0.055, respectively, compared with baseline), as well as the proportion of the CD8+CD45RA+CCR7- cells, thought to represent terminally differentiated effector T cells (p = 0.03). Reductions of percentages of circulating CD4+CD28- and CD8+CD28- T cells, and (CCR7-) CD8+ total effector T cells were directly correlated with the reduction of Disease Activity Score 28 C-reactive protein (r = 0.58, p = 0.014; r = 0.47, p = 0.059; r = 0.59, p = 0.012, respectively).

CONCLUSION

After therapy with abatacept, circulating CD28- T cells and other effector populations decrease in patients with RA. This decrease is correlated with clinical response.

Targeting B cells in immune-mediated inflammatory disease: a comprehensive review of mechanisms of action and identification of biomarkers

B cell-depletion therapy, particularly using anti-CD20 treatment, has provided proof of concept that targeting B cells and the humoral response may result in clinical improvements in immune-mediated inflammatory disease. In this review, the mechanisms of action of B cell-targeting drugs are investigated, and potential biomarkers associated with response to treatment in patients with autoimmune diseases are identified. Most available data relate to B cell depletion using anti-CD20 therapy (rituximab) in patients with rheumatoid arthritis (RA). Treatment leads to significant clinical benefit, but apparently fails to deplete long-lived plasma cells, and discontinuation is associated with relapse. Biomarkers commonly used in studies of B cell-targeted therapies include rheumatoid factor, anti-citrullinated peptide antibodies, and immunoglobulin (Ig) levels. More recently, there has been interest in markers such as B cell phenotype analysis, and B lymphocyte stimulator (BLyS)/a proliferation-inducing ligand (APRIL), the latter particularly in studies of the IgG Fc-transmembrane activator and CAML interactor (TACI) fusion protein (atacicept) and anti-BLyS therapy (belimumab). Data from clinical trials of B cell-depleting agents in RA suggest that specific autoantibodies, BLyS, APRIL, and circulating and synovial B lineage cell levels may have potential as biomarkers predictive of response to treatment. Further trials validating these markers against clinical outcomes in RA are required. In patients with systemic lupus erythematosus, Fc receptors and levels of circulating immune cells (including B cells and natural killer cells) may be relevant markers.

Impact of T-cell costimulation modulation in patients with undifferentiated inflammatory arthritis or very early rheumatoid arthritis: a clinical and imaging study of abatacept (the ADJUST trial)

Background

Several agents provide treatment for established rheumatoid arthritis (RA), but a crucial therapeutic goal is to delay/prevent progression of undifferentiated arthritis (UA) or very early RA.

Objective

To determine the impact of T-cell costimulation modulation in patients with UA or very early RA.

Methods

In this double-blind, phase II, placebocontrolled, 2-year study, anti-cyclic citrullinated peptide (CCP)2-positive patients with UA (not fulfilling the ACR criteria for RA) and clinical synovitis of two or more joints were randomised to abatacept (∼10 mg/kg) or placebo for 6 months; the study drug was then terminated. The primary end point was development of RA (by ACR criteria) at year 1. Patients were monitored by radiography, MRI, CCP2, rheumatoid factor and 28 joint count Disease Activity Score (DAS28) over 2 years.

Results

At year 1, 12/26 (46%) abatacept-treated versus 16/24 (67%) placebo-treated patients developed RA (difference (95% CI) −20.5% (−47.4% to 7.8%)). Adjusted mean changes from baseline to year 1 in Genant-modified Sharp radiographic scores for abatacepttreated versus placebo-treated patients, respectively, were 0 versus 1.1 for total score, and 0 versus 0.9 for erosion score. Mean changes from baseline to year 1 in MRI erosion, osteitis and synovitis scores were 0, 0.2 and 0.2, respectively, versus 5.0, 6.7 and 2.3 in the abatacept versus placebo groups. Safety was comparable between groups; serious adverse events occurred in one patient (3.6%) in each group.

Conclusion

Abatacept delayed progression of UA/very early RA in some patients. An impact on radiographic and MRI inhibition was seen, which was maintained for 6 months after treatment stopped. This suggests that it is possible to alter the progression of RA by modulating T-cell responses at a very early stage of disease.

Trial registration number

NCT00124449.

Understanding Personalized Medicine in Rheumatoid Arthritis: A Clinician's Guide to the Future

Personalized medicine refers to the utilization of technologies at the molecular level to understand disease processes and improve health outcomes. In rheumatoid arthritis (RA) some factors associated with disease outcome have been identified. These factors have not yet been integrated into a clinically useful tool to predict disease outcome in individual patients. Developments in pharmacogenomics are moving the field forward quite rapidly. Genetic variants, which may have a role in drug metabolism mediating either drug response or toxicity, have been identified for both traditional disease modifying antirheumatic drugs and biologic agents. Choosing a medication based on a patient's characteristics (sociodemographic, clinical, genetic) will result in better utilization of resources and better clinical outcomes. The ethical, political, and legal implications of personalized medicine need to be considered as well.

Abatacept in the treatment of rheumatoid arthritis

T-cell biology has regained importance in the pathogenesis of rheumatoid arthritis. Despite the significant improvements associated with the introduction of tumor necrosis factor-alpha blockade, reasonable proportions of failures and suboptimal responses have been reported, necessitating a search for alternative targeted therapies. This has included drug therapy designed to interrupt T-cell activation via the co-stimulation pathway. Abatacept is a recombinant fusion protein that blocks the co-stimulatory signal mediated by the CD28-CD80/86 pathway, which is required for T-cell activation. Several clinical trials have confirmed the safety and efficacy of this drug in the treatment of rheumatoid arthritis. This review summarizes the clinical data supporting this line of treatment and considers the safety and efficacy data from phase II and III trials.