Sustained improvement in rheumatoid arthritis following a protocol designed to deplete B lymphocytes

Recent developments in the treatment of patients with systemic lupus erythematosus: focusing on biologic therapies

INTRODUCTION

Major trials hoping to obtain optimal disease control in systemic lupus erythematosus (SLE) are ongoing. Given its complex aetiology and pathogenesis, it is not surprising that multiple therapeutic targets have emerged and that none are uniformly successful.

AREAS COVERED

In this review, we highlight the recent, more significant studies focusing on the use of biologic therapies. There has been great emphasis on the role of B cells in SLE and many uncontrolled studies have encouraged the use of rituximab (an anti-CD20 monoclonal). Disappointingly, two major trials, EXPLORER and LUNAR did not confirm its utility, although doubts have been expressed on their trial design, and other trials using this drug are commencing. In contrast, belimumab, which blocks a B-cell activating factor, did meet its end points in two major randomised controlled clinical trials and has been approved for use in SLE by both the FDA and the European Medicines Agency. Encouraging, albeit preliminary, results with epratuzumab (which blocks CD22) have also been reported.

EXPERT OPINION

In addition to targeting B cells, other approaches including biologics, which modulate T-cell function and block interleukin-6 and interferon-α, have been explored. Finally, we review the recent developments in the use of conventional drugs, such as cyclophosphamide and mycophenolate.

Rituximab for the treatment of rheumatoid arthritis: an update

Rituximab is a chimeric monoclonal antibody that targets the CD20 molecule expressed on the surface of B cells. It was first used in the treatment of non-Hodgkin's lymphoma and later approved for the treatment of rheumatoid arthritis (RA) that does not respond adequately to disease-modifying antirheumatic drugs, including the anti-tumor-necrosis-factor (TNF) biologics. Sustained efficacy in RA can be achieved by repeated courses of rituximab. However, the optimal dose and retreatment schedule of rituximab in RA remains to be established. Seropositivity, complete B cell depletion shortly after treatment, and previous failure to no more than one anti-TNF agent are three factors associated with greater clinical benefits to rituximab. Infusion reaction to the first dose of rituximab occurs in approximately 25% of RA patients, and the incidence reduces with subsequent exposure. Immunogenicity to the chimeric compound occurs in 11% of RA patients, but this does not correlate with its efficacy in B cell depletion. Extended observation of randomized controlled trials in RA does not reveal a significant increase in the incidence of serious infections related to rituximab compared to placebo groups, and the infection rate remains static over time. Repeated treatment with rituximab is associated with hypogammaglobulinemia, which may increase the risk of serious, but rarely opportunistic, infections. Reactivation of occult hepatitis B infection has been reported in RA patients receiving rituximab, but no increase in the incidence of tuberculosis was observed. Screening for baseline serum immunoglobulin G level and hepatitis B status (including occult infection) is important, especially in Asian countries where hepatitis B infection is prevalent. The rare but fatal progressive multifocal leukoencephalopathy linked to the use of rituximab has to be noted. Postmarketing surveillance and registry data, particularly in Asia, are necessary to establish the long-term efficacy and safety of rituximab in the treatment of RA.

Follicular B cells in thyroids of mice with spontaneous autoimmune thyroiditis contribute to disease pathogenesis and are targets of anti-CD20 antibody therapy

B cells are required for development of spontaneous autoimmune thyroiditis (SAT) in NOD.H-2h4 mice where they function as important APCs for activation of CD4(+) T cells. Depletion of B cells using anti-CD20 effectively inhibits SAT development. The goals of this study were to characterize the B cells that migrate to thyroids in SAT, and to determine whether anti-CD20 effectively targets those B cells in mice with established SAT. The results showed that most thyroid-infiltrating B cells in mice with SAT are follicular (FO) B cells. Expression of CD80, CD86, and CD40 was significantly increased on FO, but not marginal zone, splenic B cells after SAT development. Thyroid-infiltrating and peripheral blood B cells had lower expresion of CD20 and CD24 compared with splenic and lymph node FO B cells. Despite reduced CD20 expression, anti-CD20 depleted most B cells in thyroids of mice with established SAT within 3 d. B cell depletion in thyroids of mice given anti-CD20 was more complete and longer lasting than in spleen and lymph nodes and was comparable to that in blood. Circulation of B cells was required for effective and rapid removal of B cells in thyroids because preventing lymphocyte egress by administration of FTY720 abrogated the effects of anti-CD20 on thyroid B cells. Therefore, the FO subset of B cells preferentially contributes to SAT development and persistence, and anti-CD20 targeting of FO B cells effectively eliminates B cells in the target organ even though thyroid B cells have decreased CD20 expression.

Cost-effectiveness of abatacept for moderate-to-severe rheumatoid arthritis

Abatacept, a selective T-cell costimulation modulator, has become a valuable treatment option for those with moderately to severely active rheumatoid arthritis. Given new clinical evidence, for the first time guidelines from the American College of Rheumatology and Canadian Rheumatology Association are promoting the consideration of abatacept as the first biologic added to initial traditional disease-modifying antirheumatic drugs once an inadequate response to disease-modifying antirheumatic drug monotherapy has been established, putting abatacept at the same line of treatment options as TNF-α inhibitors or rituximab. Since the advent of the subcutaneous formulation of abatacept, positive results from its clinical trials have further increased its appeal. In light of these changes, a review of the literature was conducted on the cost-effectiveness of abatacept for moderate-to-severe rheumatoid arthritis. Here we discuss current evidence, gaps in the literature and abatacept's future outlook.

CTRP3 plays an important role in the development of collagen-induced arthritis in mice

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease exhibited most commonly in joints. We found that the expression of C1qtnf3, which encodes C1q/TNF-related protein 3 (CTRP3), was highly increased in two mouse RA models with different etiology. To elucidate the pathogenic roles of CTRP3 in the development of arthritis, we generated C1qtnf3(-/-) mice and examined the development of collagen-induced arthritis in these mice. We found that the incidence and severity score was higher in C1qtnf3(-/-) mice compared with wild-type (WT) mice. Histopathology of the joints was also more severe in C1qtnf3(-/-) mice. The levels of antibodies against type II collagen and pro-inflammatory cytokine mRNAs in C1qtnf3(-/-) mice were higher than WT mice. These observations indicate that CTRP3 plays an important role in the development of autoimmune arthritis, suggesting CTRP3 as a possible medicine to treat RA.

Reactivation of latent viruses in individuals receiving rituximab for new onset type 1 diabetes

BACKGROUND

Rituximab has been successfully used as an experimental therapy in different autoimmune diseases. Recently, a double-blind placebo-controlled phase-2 study in early onset type 1 diabetes showed that rituximab delayed progression of the disease. However, like with any immunosuppressive therapy, there is a concern of opportunistic viral reactivations with the use of rituximab, including herpes and polyomaviruses.

OBJECTIVES

To study the incidence of new infections and reactivations with BK, JC, Epstein-Barr and cytomegalovirus (BKV, JCV, EBV and CMV) in T1D participants in the phase-2 rituximab study.

STUDY DESIGN

Subjects received 4 weekly doses of rituximab (N = 57) or placebo (N = 30) during the first month of study. Blood samples obtained at weeks 0, 12, 26, 56 and 78 were assayed for CMV, EBV, BKV and JCV by real-time DNA PCR and serology.

RESULTS

EBV reactivations were diagnosed by PCR in 25% of placebo, but none of rituximab recipients (p < 0.01). There were no episodes of CMV viremia in either treatment group. BKV viremias were significantly more common in the rituximab recipients (9%) compared with placebo controls (0, p < 0.01). No JCV reactivations were detected in this study, but among 6 rituximab and 2 placebo recipients who seroconverted for JCV during the study, only one rituximab recipient had detectable viremia. All infections were asymptomatic.

CONCLUSIONS

Four doses of rituximab administered to individuals with early onset T1D decreased the incidence of asymptomatic EBV reactivations, as predicted by the rituximab-mediated elimination of memory B-cells, but increased the frequency of asymptomatic viremias caused by polyomaviruses.

Rituximab biosimilars

INTRODUCTION

Rituximab is a monoclonal antibody targeting CD20, used to treat B cell malignancies and B cell-mediated autoimmune diseases. Rituximab has the largest market of any monoclonal antibody therapeutic. Its patent will expire within the next few years and several manufacturers have already produced or are developing rituximab biosimilars that aim to match the innovator rituximab as closely as possible.

AREAS COVERED

In this review, we discuss key factors that determine the efficacy of rituximab therapy, potential technical challenges in the manufacture and evaluation of biosimilars, regulatory considerations regarding the review and approval of biosimilars, and the current status of biosimilar rituximab development by various manufacturers. Due to the nature of the topic, literature searches included conference abstracts, regulatory and industry websites as well as peer reviewed literature.

EXPERT OPINION

Cost is a key limitation of current biologics usage and there is a political impetus to the licensing of biosimilars. Concerns regarding potential dissimilarities of biosimilars are legitimate, but surmountable with techniques for in vitro, in vivo and clinical testing and more clearly defined regulatory requirements. These should provide reassurance to prescribers. However, the cost of manufacturing and licensing a biosimilar remains high and the reduction in cost may be more limited than for a non-biologic small molecule drug and its generic version. This cost reduction will be critical to the impact and use of rituximab biosimilars.

Regulatory B cells in autoimmune diseases

B cells are generally considered to be positive regulators of the immune response because of their capability to produce antibodies, including autoantibodies. The production of antibodies facilitates optimal CD4(+) T-cell activation because B cells serve as antigen-presenting cells and exert other modulatory functions in immune responses. However, certain B cells can also negatively regulate the immune response by producing regulatory cytokines and directly interacting with pathogenic T cells via cell-to-cell contact. These types of B cells are defined as regulatory B (Breg) cells. The regulatory function of Breg cells has been demonstrated in mouse models of inflammation, cancer, transplantation, and particularly in autoimmunity. In this review, we focus on the recent advances that lead to the understanding of the development and function of Breg cells and the implications of B cells in human autoimmune diseases.

B-cell depletion in SLE: clinical and trial experience with rituximab and ocrelizumab and implications for study design

B cells are believed to be central to the disease process in systemic lupus erythematosus (SLE), making them a target for new therapeutic intervention. In recent years there have been many publications regarding the experience in SLE of B-cell depletion utilising rituximab, an anti-CD20 mAb that temporarily depletes B cells,reporting promising results in uncontrolled open studies and in routine clinical use. However, the two large randomised controlled trials in extra-renal lupus (EXPLORER study) and lupus nephritis (LUNAR study) failed to achieve their primary endpoints. Based on the clinical experience with rituximab this failure was somewhat unexpected and raised a number of questions and concerns, not only into the true level of benefit of B-cell depletion in a broad population but also how to test the true level of effectiveness of an investigational agent as we seek to improve the design of therapeutic trials in SLE. A better understanding of what went wrong in these trials is essential to elucidate the underlying reasons for the disparate observations noted in open studies and controlled trials. In this review, we focus on various factors that may affect the ability to accurately and confidently establish the level of treatment effect of the investigational agent, in this case rituximab, in the tw studies and explore hurdles faced in the randomised controlled trials investigating the efficacy of ocrelizumab, the humanised anti-CD20 mAb, in SLE. Further, based on the lessons learned from the clinical trials, we make suggestions that could be implemented in future clinical trial design to overcome the hurdles faced.

Protective effect of RC-3095, an antagonist of the gastrin-releasing peptide receptor, in experimental arthritis

OBJECTIVE

To evaluate the antiinflammatory effects of RC-3095 in 2 experimental models of arthritis, collagen-induced arthritis (CIA) and antigen-induced arthritis (AIA), and to determine the mechanisms of action involved.

METHODS

RC-3095 was administered daily to mice with CIA and mice with AIA, after induction of disease with methylated bovine serum albumin. Disease incidence and severity were assessed using a clinical index and evaluation of histologic features, respectively. In mice with CIA, gastrin-releasing peptide receptor (GRPR) was detected by immunohistochemical analysis, while in mice with AIA, migration of neutrophils, presence of glycosaminoglycans, and lymphocyte proliferation, determined using the MTT assay, were assessed. Expression of cytokines interleukin-17 (IL-17), IL-1β, and tumor necrosis factor α (TNFα) was evaluated in all mouse knees using enzyme-linked immunosorbent assay. Treg cell production was assessed by flow cytometry in the joints of mice with AIA.

RESULTS

In mice with AIA, administration of RC-3095 reduced neutrophil migration, mechanical hypernociception, and proteoglycan loss. These findings were associated with inhibition of the levels of all 3 proinflammatory cytokines, decreased lymphocyte proliferation, and increased Treg cell numbers. In the CIA model, treatment with RC-3095 led to a significant reduction in arthritis clinical scores and the severity of disease determined histologically. Synovial inflammation, synovial hyperplasia, pannus formation, and extensive erosive changes were all dramatically reduced in the arthritic mice treated with RC-3095. Furthermore, arthritic mice treated with RC-3095 showed a significant reduction in the concentrations of IL-17, IL-1β, and TNFα, and showed a diminished expression of GRPR.

CONCLUSION

These findings suggest that the GRP pathway has a significant role in chronic arthritis, and its inhibition can be explored as a possible therapeutic strategy in rheumatoid arthritis.

[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.

Critical analysis of the use of rituximab in mucous membrane pemphigoid: a review of the literature

BACKGROUND

Mucous membrane pemphigoid (MMP) is an autoimmune blistering disease. In patients who do not respond to conventional therapy, rituximab (RTX) may be an option. The current literature on the treatment of MMP with RTX is limited.

OBJECTIVE

In this review, the data on 28 patients with MMP treated with RTX are critically analyzed. The goal is to provide objective information useful in decision making and treatment.

METHODS

A PubMed search using the key words "rituximab" and "mucous membrane pemphigoid" was made in the English language only. The studies were divided into case reports and case series.

RESULTS

In the final analysis, 20 of 28 patients had a complete response, 3 had a partial response, 2 were nonresponders, and 1 had stabilization of disease. In 1 patient, stabilization of upper airway disease was observed but the patient developed bilateral blindness as a result of progression of disease. Hence, the patient was considered a treatment failure. One died from infection. At least half of the patients were treated with a second cycle because of relapse or lack of response.

LIMITATIONS

Long-term follow-up after RTX therapy is lacking. Hence, the clinical benefit of inducing long-term remissions cannot be assessed. Responses of individual mucosal sites cannot be differentiated. Studies on B-cell levels and antibody responses are lacking.

CONCLUSION

Using the protocol described, RTX benefits patients with recalcitrant MMP. Some patients fail treatment or experience a relapse. The ability of RTX to influence the clinical course of MMP remains to be determined.

Rituximab is more effective than second anti-TNF therapy in rheumatoid arthritis patients and previous TNFα blocker failure

Purpose

To assess the efficacy of one course of rituximab (two 1-g doses) compared to an alternative tumor necrosis factor-α (TNFα) blocker in rheumatoid arthritis patients who had experienced one previous TNFα blocker failure (eg, etanercept, adalimumab, or infliximab).

Patients and methods

The efficacy of both treatments was studied in this retrospective, multicenter, noninterventional cohort study with 196 patients. All patients had active rheumatoid arthritis defined by a Disease Activity Score-28 of ≥3.2 despite having TNFα blocker therapy, and were followed over 6.6 months on average after switching to rituximab versus a second TNFα blocker (ie, switching to etanercept, adalimumab, or infliximab) at baseline.

Results

At baseline, both cohorts showed similar demographic and disease-related characteristics (including Disease Activity Score-28). At the end of observation, mean Disease Activity Score-28 was significantly lower after treatment with rituximab than with a second TNFα blocker (−1.64 [95% confidence interval: −1.92; −1.36] versus −1.19 [95% confidence interval: −1.42; −0.96], P = 0.013). This difference between the two groups was even more pronounced when patients were seropositive for rheumatoid factor (−1.66 versus −1.17, P = 0.018) and anti-cyclic citrullinated peptide antibodies (−1.75 versus −1.06, P = 0.002). More rituximab-treated patients achieved good European League Against Rheumatism response than TNFα blocker-treated patients (30% versus 15%), and less patients were nonresponders (22% versus 35%) according to European League Against Rheumatism criteria (P = 0.022, chi-squared test).

Conclusion

Treatment with rituximab was more effective than a second TNFα blocker therapy in rheumatoid arthritis patients after failure of the first TNFα blocker. It was found that anti-cyclic citrullinated peptide antibodies may be a useful predictive biomarker for response to rituximab in patients with TNFα blocker treatment failure.

Colitis associated with biological agents

In the past, there has been considerable focus on a host of drugs and chemicals that may produce colonic toxicity. Now, a variety of new biological monoclonal antibody agents, usually administered by infusion, have appeared in the clinical realm over the last decade or so to treat different chronic inflammatory or malignant disorders.For some of these agents, adverse effects have been documented, including apparently new forms of immune-mediated inflammatory bowel disease. In some, only limited symptoms have been recorded, but in others, severe colitis with serious complications, such as bowel perforation has been recorded. In others, adverse effects may have a direct vascular or ischemic basis, while other intestinal effects may be related to a superimposed infection. Some new onset cases of ulcerative colitis or Crohn’s disease may also be attributed to the same agents used to treat these diseases, or be responsible for disease exacerbation. Dramatic and well documented side effects have been observed with ipilimumab, a humanized monoclonal antibody developed to reduce and overcome cytotoxic T-lymphocyte antigen 4, a key negative feedback regulator of the T-cell anti-tumor response. This agent has frequently been used in the treatment of different malignancies, notably, malignant melanoma. Side effects with this agent occur in up to 40% and these are believed to be largely immune-mediated. One of these is a form of enterocolitis that may be severe, and occasionally, fatal. Other agents include rituximab (an anti-CD20 monoclonal antibody), bevacizumab (a monoclonal antibody against the vascular endothelial growth factor) and anti-tumor necrosis factor agents, including infliximab, adalimumab and etanercept.

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.

Autoimmune arthritis: the interface between the immune system and joints

Rheumatoid arthritis (RA) is an autoimmune disease, characterized by chronic inflammation and synovial hyperplasia in the joints that ultimately lead to cartilage and bone destruction. A wealth of research has shown that CD4(+) T cells, especially IL-17 producing helper T (Th17) cells, play an important role in RA development. However, it still remains to be clarified how the systemic immune response results in the local joint disorders. Studies on animal models of RA have shed light on the importance of the interaction between immune cells and joint-specific mesenchymal cells. In particular, joint-specific mesenchymal cells contribute to the Th17-mediated augmentation of the inflammatory phase in RA by promoting the migration of Th17 cells to the inflammatory joint and then homeostatic proliferation with increase in IL-17 production. In addition, recent progress in osteoimmunology has provided new insights into the pathogenesis of the bone destruction phase in RA. Of note, Th17 cells have been shown to enhance the differentiation of osteoclasts via joint-specific mesenchymal cells. Thus, the interaction of CD4(+) T cells and nonhematopoietic mesenchymal cells in joints plays a key role in RA pathogenesis during both the inflammatory and bone destruction phases. Focusing on this interaction will lead to a better understanding of the mechanism by which the systemic immune response results in local joint disorders and also helps provide a molecular basis for novel therapeutic strategies.

Treatment of arthritis by macrophage depletion and immunomodulation: testing an apoptosis-mediated therapy in a humanized death receptor mouse model

OBJECTIVE

To determine the therapeutic efficacy and immunomodulatory effect of an anti-human death receptor 5 (DR5) antibody, TRA-8, in eliminating macrophage subsets in a mouse model of type II collagen-induced arthritis (CIA).

METHODS

A human/mouse-chimeric DR5-transgenic mouse, under the regulation of a mouse 3-kb promoter and a loxP-flanked STOP cassette, was generated and crossed with an ubiquitous Cre (Ubc.Cre) mouse and a lysozyme M-Cre (LysM.Cre)-transgenic mouse to achieve inducible or macrophage-specific expression. Chicken type II collagen was used to induce CIA in mice, which were then treated with an anti-human DR5 antibody, TRA-8. Clinical scores, histopathologic severity, macrophage apoptosis and depletion, and T cell subset development were evaluated.

RESULTS

In human/mouse DR5-transgenic Ubc.Cre mice with CIA, transgenic DR5 was most highly expressed on CD11b+ macrophages, with lower expression on CD4+ T cells. In human/mouse DR5-transgenic LysM.Cre mice, transgenic DR5 was restrictively expressed on macrophages. Both in vivo near-infrared imaging of caspase activity and TUNEL staining demonstrated that TRA-8 rapidly induced apoptosis of macrophages in inflamed synovium. Depletion of pathogenic macrophages by TRA-8 led to significantly reduced clinical scores for arthritis; decreased macrophage infiltration, synovial hyperplasia, osteoclast formation, joint destruction, cathepsin activity, and inflammatory cytokine expression in joints; reduced numbers of Th17 cells; and an increased number of Treg cells in draining lymph nodes.

CONCLUSION

The anti-human DR5 antibody TRA-8 was efficacious in reducing the severity of arthritis via targeted depletion of macrophages and immunomodulation. Our data provide preclinical evidence that TRA-8 is a potential novel biologic agent for rheumatoid arthritis therapy.

[Rituximab in rheumatoid arthritis: a systematic review of efficacy and safety]

INTRODUCTION

The aim of the systematic review was to evaluate the safety and efficacy of rituximab for the treatment of rheumatoid arthritis patients, as part of the Consensus on the use of rituximab in rheumatoid arthritis. A document with evidence based recommendations.

METHODS

All papers published from January 2003 to September 2009 were reviewed in a systematic way in Medline, EMBASE and Cochrane Library database. The Mesh terms used were: "Rituximab", "Rheumatoid arthritis", "and Anti-CD20", "Biologics". The abstracts of the EULAR and ACR congress of 2003 to 2009 were also reviewed, as well data of Roche Pharma. Two rheumatologists (BHC y MGH) made the bibliographic review by title and summary of each work. Two authors (BHC y RAA) selected them by quality according the GRADE SCALE after they review. The data were collected in paper. The outcomes evaluated were of efficacy in agreement with OMERACT (Outcome Measurements in Rheumatoid Arthritis Clinical Trials) and The Musculoskeletal Cochrane Study Group. The outcomes of safety evaluated were: mortality, severe infections, severe adverse events, withdraw for any cause, for severe adverse events, and for infusion related reactions. The review was conducted with Cochrane methodology. The odds ratio and relative risk for dichotomist variables; and mean difference between baseline and final measurements for continuous variables, and risk differences were calculated with RevMan 5. The number of patients needed to treat was calculated with Cates' calculator.

RESULTS

RTX is an effective drug in three groups of patients with RA: patients who fail to MTX, those who fail anti-TNF and in patients with no prior exposure to MTX. It is necessary to treat 7 (5-10) patients with RTX vs. placebo to obtain an ACR70 response; 9 (6-15) to achieve a DAS28 < 2.6; and 5 (4-8) to achieve a HAQ improvement > 0.2. Safety of the drug was similar to that of placebo except for infusion reactions where 12 (8-26) patients need to be treated with RTX vs. placebo to see a reaction to the first infusion with steroid premedication. Severe adverse events to the infusion had an incidence of 0.7% in patients of the RTX treated group. It was impossible to identify a larger increase in the number of severe infections, probably due to methodological problems, however, the risk of developing infections in patients treated with RTX seems to be comparable to that of other anti-TNF and biologics.

[Consensus on the Use of Rituximab in Rheumatoid Arthritis. A document with evidence-based recommendations. Grupo de Expertos en Rituximab. ]

INTRODUCTION

Rituximab has been employed successfully for the treatment of Rheumatoid Arthritis (RA). However, its particular mechanism of action, as well as a lack of concrete guidelines for its management have generated doubts on its use.

OBJECTIVE

To establish recommendations that facilitates the use of rituximab in common clinical practice.

METHODS

In a first Delphi round, 9 expert rheumatologists got together to develop questions on those subjects generating most doubts on the efficacy and safety of the drug. These were adapted to perform a systematic review of the evidence, which was presented in a second meeting. Nominal groups were formed to respond to each question and give a recommendation. These recommendations were presented in a second Delphi round to a larger group of experts in rheumatology. Once again recommendations were discussed, modified and voted upon. Once approved, a vote on the degree of agreement for each recommendation was carried out.

RESULTS

17 recommendations were established, 10 regarding efficacy and 7 safety. All of the efficacy recommendations except 3 presented a good or moderate degree of evidence. Among the safety recommendations, 3 had a good or moderate degree of evidence while in the rest it was indirect, scarce or non-existent and a product of expert recommendation. The degree of agreement between experts was elevated for most of the recommendations.

CONCLUSIONS

These recommendations attempt to clear doubts on the use of rituximab and establish guidelines for its use in daily practice. Efficacy recommendations have a high degree of evidence, allowing the clinician to be guided in therapeutic decisions. Safety recommendations have a lower degree of evidence.

Rituximab and its potential for the treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic systemic inflammatory disorder which causes deforming joint disease and a spectrum of extraarticular manifestations. Poor disease control may lead to functional impairment and loss of independence. In recent times a prominent role for B cells in the pathogenesis of RA has been suggested. Two major theories have been postulated to explain the role of rheumatoid factor (RF) in the RA inflammatory process and the reason for RF overproduction; the loss of tolerance model and the autonomous mutated B cell model. With this in mind, strategies have been adopted to deplete B cells including the use of the anti-CD20 antibody rituximab. Rituximab leads to complement mediated lysis of B cells as well as antibody-dependant cellular cytotoxicity. It has been hypothesized that rituximab may also initiate apoptosis in RA and alter the ability of B cells to respond to antigen and other stimuli. Several recent studies using rituximab have demonstrated significant declines in RA activity providing evidence for the role of B cells in RA. Rituximab would appear to be a major addition to the increasing therapeutic options for sufferers of RA.

Developing the next generation of monoclonal antibodies for the treatment of rheumatoid arthritis

Rheumatoid arthritis is one of the commonest autoimmune diseases affecting 0.8% of the population. Over the last decade the treatment of this chronic disease has been revolutionized by the use of monoclonal antibodies and fusion proteins, targeting molecules like tumour necrosis factor alpha. Nevertheless, approximately one-third of subjects fail to respond to these therapies and therefore significant unmet medical need remains. Following a decade of use, clinical, government and regulatory agency expectations have changed for new antibodies therapies entering this highly competitive area. In this review, we discuss the current advances being made in antibody engineering and how they are being considered and used in the development of the next generation of antibodies to meet future expectations of healthcare providers, physicians and patients. Moreover, we discuss how pattern recognition receptors may provide new antibody tractable targets that may break the cycle of autoimmunity in rheumatoid arthritis.

Anti-CCP antibodies: the past, the present and the future

Rheumatoid arthritis (RA) is an autoimmune disease characterized by autoantibodies against citrullinated antigens. The importance of citrulline for the epitopes bound by these autoantibodies, referred to as ACPA (anti-citrullinated peptide/protein antibodies), was first described in 1998. In addition to citrullinated proteins, cyclic citrullinated peptides (CCP) can also be used as test substrates for detecting ACPA. The standard test for these antibodies is the second-generation CCP (CCP2) test, which is one of the best in terms of sensitivity and specificity. The generation of ACPA is an early event in the disease course, and is dependent on the presence of certain MHC class II alleles. ACPA in the inflamed synovium have been shown to associate with citrullinated antigens to form immune complexes, resulting in progression of the inflammatory process. The involvement of ACPA in the chronicity of RA is probably the reason why ACPA-positive patients have a more erosive disease course than ACPA-negative patients. The presence of ACPA has been included in the 2010 RA classification criteria. Thus, it is important to further standardize ACPA testing, for example by including an internal serum standard, which may lead to a better distinction between low and high ACPA levels.

Decreased levels of sCD21 and sCD23 in blood of patients with systemic-juvenile arthritis, polyarticular-juvenile arthritis, and pauciarticular-juvenile arthritis

A soluble form of CD21 (sCD21) and CD23 (sCD23) is released from the surface of human white blood cells upon shedding of the extracellular domain. sCD21 circulates in a complex with cleavage fragments of C3 and sCD23, which were previously identified as ligands of membrane and soluble CD21. sCD21 seems to be a marker of chronic inflammatory disease. To assess the sCD21 and sCD23 status in patients with subsets of juvenile arthritis (JA), we determined plasma levels sCD21 and sCD23. Plasma sCD21 levels were significantly decreased in all JA subtypes (O-JA P < 0.0068; P- and S-JA P < 0.0001) compared to healthy controls. Plasma sCD23 levels were significantly decreased in P-JA and S-JA (both P < 0.0001), but not in O-JA (P < 0.3843) in comparison with healthy controls, and data statistically analyzed. Our results suggest that pathological mechanisms relevant to autoimmune disorders interfere with the regulation of both CD21 and CD23 shedding.

Targeted biological therapies for Graves' disease and thyroid-associated ophthalmopathy. Focus on B-cell depletion with Rituximab

Based on experience from the treatment of other autoimmune diseases and because of the limitations imposed by existing therapeutic options for Graves' disease (GD) and thyroid-associated ophthalmopathy (TAO), rituximab (RTX) was recently proposed as a novel therapy option. Here, we summarize the rationale for using RTX; give an overview of the possible mechanisms of action; and give an account of its effects and side-effects when used in GD and TAO. Scant evidence, originating from only a few methodologically inhomogeneous studies, suggests that RTX may prolong remission for hyperthyroidism over that seen with antithyroid drugs, at least in mild GD. Furthermore, in patients with TAO, who are unresponsive to conventional immunosuppressive therapy, RTX seems efficacious. As we wait for larger-scale randomized studies, RTX, should be considered experimental and reserved for patients who do not respond favourably to conventional therapy. It is the first in what is likely to be a series of new and emerging treatments specifically targeting relevant components of the immune system. Further studies will hopefully lead to improved and better tailored, individualized therapy for GD and especially TAO.

Targeting the B cell in rheumatoid arthritis

There has been renewed interest in the B cell as a target for the treatment of rheumatoid arthritis (RA) over the past decade. Efficacy with rituximab has been demonstrated in randomised clinical trials (RCTs) resulting in regulatory approval for patients failing tumour necrosis factor (TNF) inhibitors. Although the actual mechanism of action has not been clearly delineated, several molecules are under development to modify B cell number/function in hope of superior efficacy/safety or ease of administration. The safety of rituximab over the intermediate time point has been comparable to that seen with other biologic disease-modifying anti-rheumatic drugs (DMARDs). The recent report of cases of progressive multifocal leukoencephalopathy in three patients receiving rituximab for RA is a concern and, for now, limits rituximab to salvage therapy for the treatment-resistant patient. How this impacts on other B-cell inhibitors under development is not yet clear. Development of biomarkers that will assist our therapeutic decisions to enhance the benefit/risk ratio for our patients are needed as we move forward with further selective targeted therapies.

Cytokine pattern in very early rheumatoid arthritis favours B-cell activation and survival

OBJECTIVES

B cells play an important role in the perpetuation of RA, particularly as autoantibody-producing cells. The ICs that further develop deposit in the joints and aggravate the inflammatory process. However, B-cell contribution in the very early stage of the disease remains unknown. The main goal of this work was to determine the concentration of cytokines potentially relevant for B-cell activation in serum from very early polyarthritis patients, with <6 weeks of disease duration, who latter on evolved into very early RA (VERA).

METHODS

A proliferation-inducing ligand (APRIL), B-cell activating factor (BAFF) and IL-21 levels were measured by ELISA in the serum of VERA, other very early arthritis (VEA), established RA patients and controls. SF samples of established RA were also analysed.

RESULTS

VERA patients have higher levels of APRIL and BAFF as compared with VEA, established RA and controls. Furthermore, APRIL and BAFF levels are also significantly elevated in RA-SF when compared with serum.

CONCLUSIONS

The increased levels of APRIL and BAFF in VERA patients suggests that B-cell activation and the development of autoreactive B-cell responses might be crucial in early phases of RA. Therefore, APRIL and BAFF could be promising targets for therapy in the early phase of RA.

Biological agents targeting beyond TNF-alpha

Biological agents represent an important addition to the therapies for immuno-inflammatory conditions and have a great impact on the disease course and quality of life of these patients. However, recent reports of serious infections like tuberculosis, demyelinating and neurodegenerative diseases, pancytopenia, cardiovascular diseases, etc. after anti-TNF therapy raised questions on their safety. Hence, focus is shifted towards drugs targeting cytokine checkpoints in the inflammatory cascades beyond TNF-α. Existing therapeutic targets include the biological agents acting as antagonists of various inflammatory cytokines (Anakinra, Tocilizumab, Atlizumab) and modulators of CD80 or CD86-CD28 co-stimulatory signal (Abatacept), CD2 receptors on T-cells (Alefacept), CD11a, subunit of leukocyte function-associated antigen 1 (Efalizumab), vitronectin receptor and CD20 antigen on pre-B, immature and mature B cells (Rituximab). With the introduction of these novel molecules the future for immunomodulatory intervention in rheumatology, asthma, crohn's disease, septic shock etc. looks very promising. These novel therapeutic agents could truly give a new hope to the clinician to modify the disease and achieve tangible improvements in the lives of the patients.