Efficacy and safety of rituximab in patients with active proliferative lupus nephritis: the Lupus Nephritis Assessment with Rituximab study

Ten developments in the use of biologicals for systemic lupus erythematosus

Belimumab has recently been approved, and several other types of biological therapy with different mechanisms of action are currently in phase II and III studies. This review puts these approaches in context, emphasizing mechanistic categories and clinical trial designs. Most of the promising approaches involve B cell depletion or modulation. Post-approval experience with belimumab is critically reviewed.

Novel therapeutic agents in clinical development for systemic lupus erythematosus

Conventional immunosuppressive therapies have radically transformed patient survival in systemic lupus erythematosus (SLE), but their use is associated with considerable toxicity and a substantial proportion of patients remain refractory to treatment. A more comprehensive understanding of the complexity of SLE immunopathogenesis has evolved over the past decade and has led to the testing of several biologic agents in clinical trials. There is a clear need for new therapeutic agents that overcome these issues, and biologic agents offer exciting prospects as future SLE therapies.An array of promising new therapies are currently emerging or are under development including B-cell depletion therapies, agents targeting B-cell survival factors, blockade of T-cell co-stimulation and anti-cytokine therapies, such as monoclonal antibodies against interleukin-6 and interferon-α.

Rituximab in the treatment of resistant lupus nephritis: therapy failure in rapidly progressive crescentic lupus nephritis

OBJECTIVE

The objective of this paper is to report the clinical outcome of B cell depletion therapy in 18 patients with refractory lupus nephritis (LN).

METHODS

Eighteen patients received rituximab on an open-label basis with prospective evaluations. All patients had renal disease refractory to conventional immunosuppressive therapy, including intravenous cyclophosphamide (CyC). All patients fulfilled the revised ACR classification criteria for SLE. Rituximab was given as 2 × 1 g infusions with 500 mg iv CyC and 500 mg iv methylprednisolone, two weeks apart. Complete remission (CR) of nephritis at six months was defined as normal serum creatinine and serum albumin levels, inactive urine sediment, and proteinuria < 0.5 g/day; partial remission (PR) was defined as a ≥50% improvement in all renal parameters that were abnormal at baseline. Clinical response was assessed by the British Isles Lupus Assessment Group (BILAG) score pre- and post-rituximab treatment, and efficacy was recorded by extent and duration of B lymphocyte depletion (normal range 0.100-0.500 × 10(9)/l). Follow-up data were collected at six months, one year post-treatment and at the most recent clinic visit.

RESULTS

At six months, 11/18 patients reached renal CR and two of 18 PR. The mean global BILAG scores for responders decreased from 15 (SD 10) to 5 (SD 3), and a total of ten A scores disappeared. Five patients failed to show complete or partial renal response despite peripheral B lymphocyte count depletion, and progressed to end-stage renal failure (ESRF) and dialysis. Four of these patients had severe proliferative, crescentic nephritis, of whom three had Class IV-G, one Class III and one late membranous glomerulonephritis. One patient died six years after rituximab therapy from overwhelming sepsis while on long-term haemodialysis.

CONCLUSION

Rituximab therapy achieved a response in 13/18 patients with refractory LN. However, in patients with rapidly progressive crescentic LN, when there is already evidence of significant renal impairment, rituximab therapy may not prevent progression to ESRF and dialysis. Our data also suggest that severe Class IV-G LN may be associated with a poor response to therapy.

Anti B-cell therapy against refractory thrombocytopenia in SLE and MCTD patients: long-term follow-up and review of the literature

OBJECTIVE

The objective of this study was to retrospectively evaluate the clinical and immunological effects of anti-B cell treatment in patients with systemic lupus erythematosus (SLE) and mixed connective-tissue disease (MCTD) with autoimmune thrombocytopenia (AITP) refractory to conventional immunosuppressive treatment.

METHODS

Rituximab (RTX) was added to the ongoing treatment of 16 patients (median age 36 years, range 17-84, all female) with treatment-resistant AITP. Thirteen patients had SLE and three had MCTD. RTX was given intravenously on four occasions during four consecutive weeks at a dose of 375 mg/m(2). Clinical and laboratory disease activity variables recorded at every follow-up visit were analyzed.

RESULTS

The median disease duration before RTX treatment was nine years (range 0.2-27) and the median post-treatment follow-up time was 28 months (range 3 to 92). Ten patients (63%) were treated repeatedly with RTX during the follow-up period. Complete depletion of B cells was achieved in 94% of cases one month after RTX treatment. A significant increase (p = 0.0001) of platelet counts was seen already after one month (median 58 × 10(9)/ml vs 110 × 10(9)/ml) whereas within three months platelet counts normalized in 10 patients (median 223 × 10(9)/ml). Three patients did not respond to RTX treatment (median platelet count 69 × 10(9)/ml). High titers of anti-platelet antibodies were detected in seven patients before RTX treatment, and the autoantibody titers decreased significantly (p < 0.03) after RTX treatment in six of these patients who also achieved complete remission. A review of the literature revealed 24 articles including 18 case reports, one retrospective cohort study and five prospective studies documenting the outcomes of 65 RTX-treated patients with SLE- or MCTD-related thrombocytopenia with an overall treatment response rate of 80%. In conclusion, these findings indicate that RTX is an additional potent therapeutic treatment option for SLE patients with AITP refractory to conventional immunosuppressive treatment whereas best response may be expected in patients with high titers of anti-platelet antibodies at baseline.

B-cell depletion therapy and pregnancy outcome in severe, refractory systemic autoimmune diseases

OBJECTIVE

To study the pregnancy outcome following Rituximab treatment before conception in patients with refractory autoimmune rheumatic diseases.

METHODOLOGY

Five women with systemic lupus erythematosus (SLE) and 1 woman with ANCA positive vasculitis fulfilling the respective ACR classification criteria were studied retrospectively when they became pregnant following rituximab treatment for refractory disease. Rituximab was given as a 1 g infusion together with 500 mg Methylprednisolone, on day 1 and day 15 after written informed consent.

RESULTS

The median age was 34 (range 32-39) years and median disease duration was 10 (range 5-16) years. All the patients achieved complete B-cell depletion < 1 cell/μL at 1 month and <5 cells/μL at 6 months with prolonged B-cell depletion. Four women had successful pregnancies with median gestational age of 38 (range 31-40) weeks; median weight of the new born was 3.25 (range1.17-3.3) kg with no documented adverse neonatal events. One patient with lupus nephritis (LN) had a premature delivery and increasing proteinuria in the third trimester. One other patient with LN had a premature delivery and the new born had oesophageal atresia.

CONCLUSION

We report a child with oesophageal atresia born to a mother with lupus nephritis who had received Rituximab 12 months prior to conception, while four other pregnancies in women with SLE resulted in morphologically normal children. We also describe the first report, to our knowledge, of a successful pregnancy outcome in a woman with granulomatosis with polyangiitis treated with rituximab.

Cellular targeting in autoimmunity

Many biologic agents that were first approved for the treatment of malignancies are now being actively investigated and used in a variety of autoimmune diseases such as rheumatoid arthritis (RA), antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, systemic lupus erythematosus (SLE), and Sjogren's syndrome. The relatively recent advance of selective immune targeting has significantly changed the management of autoimmune disorders and in part can be attributed to the progress made in understanding effector cell function and their signaling pathways. In this review, we will discuss the recent FDA-approved biologic therapies that directly target immune cells as well as the most promising investigational drugs affecting immune cell function and signaling for the treatment of autoimmune disease.

Renal involvement in autoimmune connective tissue diseases

Connective tissue diseases (CTDs) are a heterogeneous group of disorders that share certain clinical presentations and a disturbed immunoregulation, leading to autoantibody production. Subclinical or overt renal manifestations are frequently observed and complicate the clinical course of CTDs. Alterations of kidney function in Sjögren syndrome, systemic scleroderma (SSc), auto-immune myopathies (dermatomyositis and polymyositis), systemic lupus erythematosus (SLE), antiphospholipid syndrome nephropathy (APSN) as well as rheumatoid arthritis (RA) are frequently present and physicians should be aware of that.In SLE, renal prognosis significantly improved based on specific classification and treatment strategies adjusted to kidney biopsy findings. Patients with scleroderma renal crisis (SRC), which is usually characterized by severe hypertension, progressive decline of renal function and thrombotic microangiopathy, show a significant benefit of early angiotensin-converting-enzyme (ACE) inhibitor use in particular and strict blood pressure control in general. Treatment of the underlying autoimmune disorder or discontinuation of specific therapeutic agents improves kidney function in most patients with Sjögren syndrome, auto-immune myopathies, APSN and RA.In this review we focus on impairment of renal function in relation to underlying disease or adverse drug effects and implications on treatment decisions.

B-cell targeted therapeutics in clinical development

B lymphocytes are the source of humoral immunity and are thus a critical component of the adaptive immune system. However, B cells can also be pathogenic and the origin of disease. Deregulated B-cell function has been implicated in several autoimmune diseases, including systemic lupus erythematosus, rheumatoid arthritis, and multiple sclerosis. B cells contribute to pathological immune responses through the secretion of cytokines, costimulation of T cells, antigen presentation, and the production of autoantibodies. DNA-and RNA-containing immune complexes can also induce the production of type I interferons, which further promotes the inflammatory response. B-cell depletion with the CD20 antibody rituximab has provided clinical proof of concept that targeting B cells and the humoral response can result in significant benefit to patients. Consequently, the interest in B-cell targeted therapies has greatly increased in recent years and a number of new biologics exploiting various mechanisms are now in clinical development. This review provides an overview on current developments in the area of B-cell targeted therapies by describing molecules and subpopulations that currently offer themselves as therapeutic targets, the different strategies to target B cells currently under investigation as well as an update on the status of novel therapeutics in clinical development. Emerging data from clinical trials are providing critical insight regarding the role of B cells and autoantibodies in various autoimmune conditions and will guide the development of more efficacious therapeutics and better patient selection.

B cell biology: implications for treatment of systemic lupus erythematosus

B cells are critical players in the orchestration of properly regulated immune responses, normally providing protective immunity without autoimmunity. Balance in the B cell compartment is achieved through the finely regulated participation of multiple B cell populations with different antibody-dependent and independent functions. Both types of functions allow B cells to modulate other components of the innate and adaptive immune system. Autoantibody-independent B cell functions include antigen presentation, T cell activation and polarization, and dendritic cell modulation. Several of these functions are mediated by the ability of B cells to produce immunoregulatory cytokines and chemokines and by their critical contribution to lymphoid tissue development and organization including the development of ectopic tertiary lymphoid tissue. Additionally, the functional versatility of B cells enables them to play either protective or pathogenic roles in autoimmunity. In turn, B cell dysfunction has been critically implicated in the pathophysiology of systemic lupus erythematosus (SLE), a complex disease characterized by the production of autoantibodies and heterogeneous clinical involvement. Thus, the breakdown of B cell tolerance is a defining and early event in the disease process and may occur by multiple pathways, including alterations in factors that affect B cell activation thresholds, B cell longevity, and apoptotic cell processing. Once tolerance is broken, autoantibodies contribute to autoimmunity by multiple mechanisms including immune-complex mediated Type III hypersensitivity reactions, type II antibody-dependent cytotoxicity, and by instructing innate immune cells to produce pathogenic cytokines including IFNα, TNF and IL-1. The complexity of B cell functions has been highlighted by the variable success of B cell-targeted therapies in multiple autoimmune diseases, including those conventionally viewed as T cell-mediated conditions. Given the widespread utilization of B cell depletion therapy in autoimmune diseases and the need for new therapeutic approaches in SLE, a better understanding of human B cell subsets and the balance of pathogenic and regulatory functions is of the essence.

Minimising steroids in lupus nephritis – will B cell depletion pave the way?

The aim of this review is to briefly explore how steroids came to be a presumed adjunct to all treatment regimens for lupus nephritis, despite being the main cause of long term damage among patients with lupus and despite increasingly effective alternative agents. I then go on to compare and contrast how differently immunosuppression regimens have developed in the world of solid organ transplantation. Almost from the start of transplantation a clear goal was to develop steroid sparing regimens – and now units such as our own routinely use induction with a biological, a single week of steroids and then monotherapy with tacrolimus. There has been a clear trend of using biologicals as induction agents and less immunosuppression in the long run but with improved outcomes. The drive has not been the same in lupus nephritis despite there being almost no evidence to support the use of steroids and certainly nothing to suggest correct dosage and timing. Rituximab, a B cell depleting antibody, offers great promise as a treatment agent despite the negative randomised control LUNAR trial. I briefly review our own data, demonstrating that early use of rituximab in lupus nephritis allows omission of oral steroids with excellent rates of remission (complete and partial). I review why the LUNAR trial should not discourage the use of rituximab. Finally, I introduce the RITUXILUP trial, a multicentre randomised controlled trial we are developing to formally evaluate our oral steroid avoiding regimen against a standard treatment regimen of mycophenolate mofetil and steroids. We have to follow the lead of our transplant colleagues and challenge the assumption that the future for lupus nephritis cannot be steroid free.

Rituximab treatment in lupus nephritis – where do we stand?

Renal involvement in systemic lupus erythematosus (SLE) is a severe disease manifestation in which novel therapeutic strategies are needed, especially in non-responding patients or patients who relapse after conventional treatment. Rituximab has been used as off-label treatment for lupus nephritis (LN) during the last decade, and to date reports on the clinical effects on more than 400 patients, including the randomized controlled LUNAR study population, have been published. Despite promising results obtained from observational studies and registries, with complete or partial renal response after 6–12 months in 67–77% of patients, the LUNAR trial failed to attain the primary endpoint and rituximab is today unlikely to be approved as treatment for LN. Rituximab has mainly been used as induction therapy in combination with standard of care but the optimal treatment protocol is still to be determined. From observational studies, rituximab has been shown to be efficient in both proliferative and membranous LN, and histopathological studies have demonstrated improvement in renal activity. Adverse events mainly include infusion reactions and infections. Although not approved for the treatment of LN, the currently available data support that rituximab may be used in severe, refractory cases of LN.

CD22 and autoimmune disease

CD22 is a 140-kDa member of the Siglec family of cell surface proteins that is expressed by most mature B-cell lineages. As a co-receptor of the B-cell receptor (BCR), it is known to contribute to the sensitive control of the B-cell response to antigen. Cross-linking of CD22 and the BCR by antigen triggers the phosphorylation of CD22, which leads to activation of signaling molecules such as phosphatases. Signal transduction pathways involving CD22 have been explored in a number of mouse models, some of which have provided evidence that in the absence of functional CD22, B cells have a "hyperactivated" phenotype, and suggest that loss of CD22 function could contribute to the pathogenesis of autoimmune diseases. Modulating CD22 activity has therefore been suggested as a possible therapeutic approach to such diseases. For example, the novel CD22-targeting monoclonal antibody epratuzumab is currently under investigation as a treatment for the connective tissue disorder systemic lupus erythematosus (SLE).

Urine biomarkers in juvenile-onset SLE nephritis

Over 80 % of patients with juvenile-onset systemic lupus erythematosus will have renal involvement compared to 40 % with adult-onset disease. Up to 44 % of children who do have lupus nephritis (LN) progress to renal failure in early adulthood. Improved methods of detecting onset of LN would allow earlier treatment, which may prevent irreversible renal scarring and a decline in renal function. Current conventional markers of disease activity fail to adequately predict renal lupus flares and include proteinuria, complement levels, anti-double-stranded DNA antibodies and serum creatinine concentrations. Standardized histological classification is currently the gold standard for diagnosing and classifying LN, but its invasive nature limits routine use for monitoring, especially in a childhood population. Novel biomarkers need to be sensitive and specific-and preferably non-invasive and cost-effective. The most promising biomarkers in juvenile-onset LN include urinary neutrophil gelatinase associated lipocalin, monocyte chemoattractant protein 1 and transforming growth factor-beta, although many others have been identified and are under investigation. No one biomarker yet discovered is unique to LN, indicating an overlap in disease pathophysiology. It is likely that a combination of biomarkers will be required for assessing disease flare detection, response to treatment and prognostic information. Potential biomarkers require longitudinal validation in large paediatric, prospective cohorts to assess their ability to act as clinically useful adjuncts.

B-cell-targeted therapies in systemic lupus erythematosus

Autoreactive B cells are one of the key immune cells that have been implicated in the pathogenesis of systemic lupus erythematosus (SLE). In addition to the production of harmful auto-antibodies (auto-Abs), B cells prime autoreactive T cells as antigen-presenting cells and secrete a wide range of pro-inflammatory cytokines that have both autocrine and paracrine effects. Agents that modulate B cells may therefore be of potential therapeutic value. Current strategies include targeting B-cell surface antigens, cytokines that promote B-cell growth and functions, and B- and T-cell interactions. In this article, we review the role of B cells in SLE in animal and human studies, and we examine previous reports that support B-cell modulation as a promising strategy for the treatment of this condition. In addition, we present an update on the clinical trials that have evaluated the therapeutic efficacy and safety of agents that antagonize CD20, CD22 and B-lymphocyte stimulator (BLyS) in human SLE. While the results of many of these studies remain inconclusive, belimumab, a human monoclonal antibody against BLyS, has shown promise and has recently been approved by the US Food and Drug Administration as an indicated therapy for patients with mild to moderate SLE. Undoubtedly, advances in B-cell immunology will continue to lead us to a better understanding of SLE pathogenesis and the development of novel specific therapies that target B cells.

Efficacy and tolerability of rituximab in patients with rhupus

Rhupus in an infrequent disease in which an overlap between lupus eritematosus and rheumatoid arthritis exists. Joint manifestations are prominent and treatment with non biological DMARDs is not always satisfactory, so immunosupressors and biological agents have been tried. A prospective, open clinical study was done to evaluate efficacy and tolerability of rituximab in patients with Rhupus. The main objective was a change in DAS28 at 6 months and secondary objectives were a change in MEX-SLEDAI at 6 months, change in DAS28 and MEX-SLEDAI during follow up, steroid requirements and detection of adverse events. We included 9 women with a mean age of 43 years and disease duration of 10 years. A significant reduction in DAS28 was observed (from 5.73 at baseline to 3.02 at 6 months, P<.001). Improvement in DAS28 was maintained during follow up. At 6 months, 3 patients were in remission and 3 had low disease activity. MEX-SLEDAI diminished from 5 points at baseline to 1.22 at 6 months (P<.001). There was a negative correlation between clinical improvement and anti-CCP levels (r=-0,794, P=.011). Mean prednisone dose was reduced from 11.66mg/day at baseline to 0,55 and 1.11mg/day at 12 and 24 months. Treatment was well tolerated. In this study rituximab was effective not only for joint affection but also for other manifestations of the disease. We consider that this biological agent can be a good therapeutic option for patients with rhupus.

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.

[Recombinant proteins or monoclonal antibodies: comparative properties and interest in systemic lupus erythematosus]

The emergence of biologic therapies, such as monoclonal antibodies or recombinant fusion proteins, have revolutionized the management of autoimmune disorders, in particular rheumatoid arthritis. These biologic agents have been engineered to deplete key cellular populations or to block cytokines or molecules involved in the activation and/or the differentiation of immune cells, such as T cells or B cells. In systemic lupus erythematosus (SLE), a monoclonal antibody directed against the B-cell activating factor of the TNF family (BAFF or BLyS), belimumab, has demonstrated its efficacy in large, randomized and placebo-controlled studies, whereas rituximab, a monoclonal antibody directed against the CD20 expressed by B cells, failed to achieve his primary endpoint in renal and non-renal SLE. Studies on the safety and the efficacy of monoclonal antibodies or recombinant fusion proteins directed against other key molecules involved in the pathogenesis of SLE are ongoing.

New diagnostic tests and new therapies for glomerular diseases

There has recently been considerable progress in our understanding of the pathology and mechanisms of a number of primary glomerulopathies. However, without parallel advancement in both our diagnostic skills and treatment methods, such advances cannot be translated into clinical progress. Fortunately, a number of new promising diagnostic tests are being evaluated in patients with a variety of primary glomerulopathies including focal segmental glomerulosclerosis membranous nephropathy, IgA nephropathy, and C3 glomerulopathies. Likewise, a number of new therapeutic interventions are available to treat these entities, including the pituitary hormone ACTH, the monoclonal antibody rituximab, and the monoclonal blocker of the fifth component of complement, eculizumab. All three are already FDA-approved for at least one glomerular disease. This article will discuss these newer diagnostic tests and therapies as well as their potential roles in patients with glomerular diseases and where they fit in with the rest of our therapeutic armamentarium in treating patients with glomerular diseases.

Abatacept for lupus nephritis: alternative definitions of complete response support conflicting conclusions

OBJECTIVE

Recent clinical trials in lupus nephritis have all used different criteria to assess complete response. The objective of this analysis was to compare several previously proposed criteria, using the same data set from a large trial of abatacept in lupus nephritis (IM101075). In so doing, we sought to determine which criteria are most sensitive to differences among treatment groups and to further examine the potential of abatacept in lupus nephritis.

METHODS

Patients in the IM101075 trial received abatacept at 1 of 2 different dose regimens or placebo, both on a background of mycophenolate mofetil and corticosteroids. Using data from this trial, we assessed rates of complete response at 12 months according to 5 sets of criteria, from 1) the trial protocol, 2) the Aspreva Lupus Management Study (ALMS) trial of mycophenolate mofetil, 3) the Lupus Nephritis Assessment with Rituximab (LUNAR) trial of rituximab, 4) an ongoing National Institutes of Health trial of abatacept (Abatacept and Cyclophosphamide Combination: Efficacy and Safety Study [ACCESS]), and 5) published recommendations of the American College of Rheumatology.

RESULTS

According to the complete response definition from the IM101075 study protocol, there was no difference among treatment groups in the IM101075 study. In contrast, according to the ALMS, LUNAR, and ACCESS criteria, rates of complete response among patients in the IM101075 study were higher in both treatment groups relative to control. The largest differences were obtained with use of the LUNAR criteria (complete response rate of 6% in the control group, compared to 22% and 24% in the 2 abatacept groups).

CONCLUSION

The choice of definition of complete response can determine whether a lupus nephritis trial is interpreted as a success or a failure. The results of this analysis provide an evidence-based rationale for choosing among alternative definitions and offer a strong rationale for conducting further studies of abatacept in lupus nephritis.

Updates on B-cell immunotherapies for systemic lupus erythematosus and Sjogren's syndrome

PURPOSE OF REVIEW

Last year was marked by important clinical and mechanistic studies that improved our understanding of B-cell immunotherapy for systemic lupus erythematosus (SLE) and Sjogren's syndrome. Here, we will highlight the most relevant studies published in the last 18 months.

RECENT FINDINGS

The highlight of the year was the approval of belimumab on the basis of two major trials. On the flip side, the disappointing results of rituximab in lupus nephritis provided a clinical and mechanistic counterpoint in SLE. Still, major limitations in the LUpus Nephritis Assessment with Rituximab (LUNAR) trial, positive subset analysis and new open studies and registries continue to provide hope for and major insights into the use of B-cell depletion. In Sjogren's syndrome, the role of B-cell depletion has been further investigated, both for glandular and extraglandular manifestations of the disease with mixed results in a disease in which outcomes are notoriously hard to measure.

SUMMARY

The approval of anti-B cell activating factor therapy and an increasing body of open studies with rituximab as well as subset studies and secondary analysis of the Efficacy and Safety of Rituximab in Moderately-to-Severely Active Systemic Lupus Erythematosus (EXPLORER) and LUNAR trials provide hope for B-cell immunotherapy and significant insight into its mechanisms of action and utilization in a selected subset of patients. Ongoing clinical trials of other B-cell targeting agents are eagerly anticipated.

Lupus nephritis. How latest insights into its pathogenesis promote novel therapies

PURPOSE OF REVIEW

Lupus nephritis is a complex autoimmune disease that develops its own dynamic upon damaging the renal ultrastructure. Here, we summarize the latest pathophysiological concepts of lupus nephritis and how these translate into novel therapeutic options.

RECENT FINDINGS

Multidisciplinary research activities form a better understanding about how lupus develops from an unfortunate combination of gene variants that promote the loss of tolerance, that impair the clearance of dying cells, that regulate the immune interpretation of autoantigens as well as the peripheral control of autoreactive lymphocytes. As a new entry, nuclear particles also act as autoadjuvants mimicking viral particles and triggering interferon-alpha-dependent antiviral immune responses that cause symptoms similar to viral infection.

SUMMARY

A set of novel drugs have the potential to more specifically interfere with these pathomechanisms and raise hope to more efficiently treat lupus nephritis with fewer side-effects in the near future.

WITHDRAWN: Use of mycophenolic acid in lupus nephritis

Due to overlap of certain parts of text of our review 'Use of mycophenolic acid in lupus nephritis' with the previously published review by Zizzo, Ferraccioli and Santis, 'Mycophenolic acid in rheumatology: mechanisms of action and severe adverse events' (Reumatismo. 2010; 62(2):91-100), we request that our review is retracted with apologies to Drs. Zizzo, Ferraccioli and Santis, the editors and the readers. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

Homozygous FCGR3A-158F mutation is associated with delayed B-cell depletion following rituximab but with preserved efficacy in a patient with refractory lupus nephritis

Rituximab (RTX), an anti-CD20 monoclonal antibody, has shown promising results in a small group of systemic lupus erythematosus (SLE) patients treated for lupus nephritis (LN). However, such observations were not confirmed in the double-blind LUNAR study. Accordingly, the factors associated with the clinical response remain to be characterized. We report the case of a young woman with known LN successfully re-treated with RTX and steroids and homozygous for the low-affinity FCG3RA 158F genotype. Although B-cell depletion was delayed, complete remission with anti-DNA antibody negativity and proteinuria normalization were maintained for 5 years. The implications for disease pathogenesis and clinical monitoring are discussed.

Unmet medical needs in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease of diverse manifestations, with onset usually in young women in the third to fourth decade of life. The chronic nature of this relapsing remitting disease leads to organ damage accrual over time. Mortality and morbidity are increased in patients with SLE compared with the general population. Therapeutic advances over the last few decades have led to significant improvements in patient outcomes. Five-year survival has improved to over 90% from a low of 50% in the 1950s. However, multiple aspects of the management of SLE patients are still far from optimal. Early diagnosis remains a challenge; diagnostic delays leading to delay in definitive treatment are common. Monitoring treatment remains problematic due to the paucity of sensitive biomarkers. Current treatment regimens rely heavily on corticosteroids, even though corticosteroids are well known to cause organ damage. Treatment of refractory disease manifestations such as nephritis, recalcitrant cutaneous lesions and neurological involvement require new approaches with greater efficacy. Cognitive dysfunction is common in SLE patients, but early recognition and adequate treatment are yet to be established. Premature accelerated atherosclerosis remains a leading cause of morbidity and mortality. Fatigue is one of the most disabling symptoms, and contributes to the poor quality of life in patients with SLE. Ongoing research in SLE faces many challenges, including enrollment of homogeneous patient populations, use of reliable outcome measures and a standard control arm. The current review will highlight some of the outstanding unmet challenges in the management of this complex disease.

Multicenter retrospective analysis of the effectiveness and safety of rituximab in korean patients with refractory systemic lupus erythematosus

Objective. Although two recent randomized placebo-controlled trials of rituximab (RTX) failed to demonstrate efficacy in systemic lupus erythematosus (SLE), clinicians continue to use off-label RTX for cases refractory to current treatments. We evaluated the effectiveness and safety of rituximab for patients with refractory SLE in Korea. Methods. We retrospectively analyzed multicenter patients treated with RTX in Korea. Results. 39 SLE patients treated with RTX were included in the following manner: lupus nephritis 43.6%, hematologic 33.3%, arthritis 7.8%, myositis 7.8%, and others 7.7%. All patients had responded poorly to at least one conventional immunosuppressive agent (mean 2.5 ± 1.1, cyclophosphamide 43.6%, mycophenolate mofetil 48.7%, and other drugs) before RTX. Clinical improvements (complete or partial remission) occurred in patients with renal disease, hematologic disease, arthritis, myositis, and other manifestations at 6 months after RTX. The SLEDAI score was significantly decreased from 10.8 ± 7.1 at baseline to 6.7 ± 4.0 at 6 months, 6.2 ± 4.1 at 12 months, and 5.5 ± 3.6 at 24 months after RTX (P < 0.05). Among 28 clinical responders, 4 patients experienced a relapse of disease at 25 ± 4 months. Infections were noted in 3 patients (7.7%). Conclusion. RTX could be an effective and relatively safe therapeutic option in patients with severe refractory SLE until novel B-cell depletion therapy is available.

Treatment targets in systemic lupus erythematosus: biology and clinical perspective

Systemic lupus erythematosus (SLE) is a complex disease characterized by numerous autoantibodies and clinical involvement in multiple organ systems. The immunological events triggering the onset and progression of clinical manifestations are also complex and multi-step, including breach of tolerance in the adaptive immune system, amplification of autoimmunity through innate and adaptive immune system dysregulation, and end-organ damage. Studies of murine genetic manipulations and human risk variants have provided important clues to the cellular and molecular pathogenesis of SLE, operating at multiple of these steps. The breakdown of B-cell tolerance is probably a defining and early event in the disease process and may occur by multiple pathways, including alterations in factors that affect B-cell activation thresholds, B-cell longevity, and apoptotic cell processing. Examples of amplification of autoimmunity on the adaptive immune system side include disturbances in B-cell/T-cell collaboration. B cells can also amplify innate immune cell activation via antibody-dependent and antibody-independent mechanisms. Indeed, one of the key amplification loops in SLE is the activation of plasmacytoid dendritic cells via autoantibodies and RNA-containing and DNA-containing immune complexes, which act as Toll-like receptor ligands, stimulating the secretion of large quantities of IFNα. A more recent link between the innate and adaptive immune system in SLE includes the neutrophil, which can be primed by interferon and autoantibodies to release neutrophil extracellular traps as an additional source of immunogenic DNA, histones, and neutrophil proteins. The innate immune system activation then feeds back, driving autoreactive B-cell and T-cell survival and maturation. This self-perpetuating disease cycle creates the opportunity for targeted treatment inventions at multiple steps.

B cell elimination in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disorder with a worldwide distribution, potentially life-threatening with considerable morbidity. The elimination of pathogenic B cells has emerged as a rational therapeutic option. Many open label studies have reported encouraging results in which clinical and serological remission have invariably been described, often enabling the reduction of steroid and immunosuppressive treatment. However, the results from randomized controlled studies have been disappointing and several questions remain to be answered. In this review we will focus on results of B cell direct depletion in the treatment of patients with systemic lupus erythematosus.

The pathogenesis of systemic lupus erythematosus-an update

Systemic lupus erythematosus (SLE, lupus) is characterized by a global loss of self-tolerance with activation of autoreactive T and B cells leading to production of pathogenic autoantibodies and tissue injury. Innate immune mechanisms are necessary for the aberrant adaptive immune responses in SLE. Recent advances in basic and clinical biology have shed new light on disease mechanisms in lupus, with this review discussing the recent studies that offer valuable insights into disease-specific therapeutic targets.

Accelerated atherosclerosis in SLE: mechanisms and prevention approaches

Systemic lupus erythematosus (SLE) is a multi-organ autoimmune disease characterized by increased serum autoantibody levels and tissue damage. With improved diagnosis and more effective treatment of the resultant kidney disease, accelerated atherosclerosis has become a major cause of morbidity in patients suffering from SLE. Although the exact mechanisms for SLE-accelerated atherosclerosis are unknown, multiple factors have been established as potential players in this process. Among these potential players are dysregulation of T and B cell populations and increased circulating levels of inflammatory cytokines. In addition, SLE patients exhibit a proatherogenic lipid profile characterized by low HDL and high LDL and triglycerides. Recent therapeutic approaches have focused on targeting B cells, the producers of autoantibodies, but most studies do not consider the effects of these treatments on atherosclerosis. Evidence suggests that T cells play a major role in SLE-accelerated atherosclerosis. Therefore, therapies targeted at T cells may also prove invaluable in treating SLE and atherosclerosis.

B-cell targeted therapy in systemic lupus erythematosus: potential of rituximab

Systemic lupus erythematosus (SLE) is a complex autoimmune disease of unknown etiology, and the limited available therapeutic options for this disease, are frustrating to both clinicians and patients. However, recent advances in the understanding of disease mechanisms have given rise to numerous studies on specific approaches to SLE treatment. Rituximab, the first chimeric, mouse-human monoclonal antibody which is directed against CD20, seems to be a new therapeutic option. The purpose of this review is to explain the current clinical evidence on the therapeutic use of rituximab in adult SLE patients. Two randomized clinical trials with rituximab (the EXPLORER and LUNAR studies) failed to prove efficacy of this drug on SLE. Ongoing data analysis continues to explain the reasons behind why this treatment fails to work. However data from open source and observational studies contrast with clinical trials results. The global analysis of this data supports the off-label use of rituximab in subsets of SLE that are refractory to standard treatment.

Lupus nephritis: a critical review

Lupus nephritis remains one of the most severe manifestations of systemic lupus erythematosus associated with considerable morbidity and mortality. A better understanding of the pathogenesis of lupus nephritis is an important step in identifying more targeted and less toxic therapeutic approaches. Substantial research has helped define the pathogenetic mechanisms of renal manifestations and, in particular, the complex role of type I interferons is increasingly recognized; new insights have been gained into the contribution of immune complexes containing endogenous RNA and DNA in triggering the production of type I interferons by dendritic cells via activation of endosomal toll-like receptors. At the same time, there have been considerable advances in the treatment of lupus nephritis. Corticosteroids have long been the cornerstone of therapy, and the addition of cyclophosphamide has contributed to renal function preservation in patients with severe proliferative glomerulonephritis, though at the cost of serious adverse events. More recently, in an effort to minimize drug toxicity and achieve equal effectiveness, other immunosuppressive agents, including mycophenolate mofetil, have been introduced. Herein, we provide a detailed review of the trials that established the equivalency of these agents in the induction and/or maintenance therapy of lupus nephritis, culminating in the recent publication of new treatment guidelines by the American College of Rheumatology. Although newer biologics have been approved and continue to be a focus of research, they have, for the most part, been relatively disappointing compared to the effectiveness of biologics in other autoimmune diseases. Early diagnosis and treatment are essential for renal preservation.

Abatacept for systemic lupus erythematosus: the outlook

Abatacept is a selective T-cell co-stimulation modulator that inhibits full T-cell activation and subsequent antibody production by B cells. Despite the efficacy of abatacept in murine lupus, randomized controlled trials in human SLE do not reveal benefit of abatacept in non-renal and renal lupus. While problems in the study design and the primary efficacy end points may contribute to the negative results of these trials, post hoc analyses using alternative definitions for clinical response suggest the possibility that abatacept may have beneficial effects in active lupus arthritis and proliferative nephritis. Future clinical trials of abatacept should target on defined subsets of SLE patients, utilize multiple pre-defined outcomes based on experience from previous studies and determine the best timing of adding abatacept on a background of minimal immunosuppressive therapies.