New Therapies for Lupus Nephritis: Figure 1

CD11b agonists offer a novel approach for treating lupus nephritis

Lupus nephritis (LN) develops in more than a third of all systemic lupus erythematosus (SLE) patients and is the strongest predictor of morbidity and mortality. Increased circulating levels of type I interferon (IFN I) and anti-double stranded DNA (anti-dsDNA) and anti-RNA binding protein (anti-RNP) antibodies lead to increased glomerular injury via leukocyte activation and glomerular infiltration. Uncontrolled Toll-like receptor (TLR) signaling in leukocytes results in increased production of IFN I and anti-dsDNA antibodies. ITGAM gene codes for integrin CD11b, the α-chain of integrin heterodimer CD11b/CD18, that is highly expressed in leukocytes and modulates TLR-dependent pro-inflammatory signaling. Three nonsynonymous SNPs in the ITGAM gene strongly correlate with increased risk for SLE and LN and with IFN I levels. Here we review the literature on the role of CD11b on leukocytes in LN. We also incorporate conclusions from several recent studies that show that these ITGAM SNPs result in a CD11b protein that is less able to suppress TLR-dependent pro-inflammatory pathways in leukocytes, that activation of CD11b via novel small molecule agonists suppresses TLR-dependent pathways, including reductions in circulating levels of IFN I and anti-dsDNA antibodies, and that CD11b activation reduces LN in model systems. Recent data strongly suggest that integrin CD11b is an exciting new therapeutic target in SLE and LN and that allosteric activation of CD11b is a novel therapeutic paradigm for effectively treating such autoimmune diseases.

Cf-02, a novel benzamide-linked small molecule, blunts NF-κB activation and NLRP3 inflammasome assembly and improves acute onset of accelerated and severe lupus nephritis in mice

In the present study, acute onset of severe lupus nephritis was successfully treated in mice using a new, benzamide-linked, small molecule that targets immune modulation and the NLRP3 inflammasome. Specifically, 6-(2,4-difluorophenyl)-3-(3-(trifluoromethyl)phenyl)-2H-benzo[e][1,3]oxazine-2,4(3H)-dione (Cf-02) (a) reduced serum levels of IgG anti-dsDNA, IL-1β, IL-6, and TNF-α, (b) inhibited activation of dendritic cells and differentially regulated T cell functions, and (c) suppressed the NF-κB/NLRP3 inflammasome axis, targeting priming and activating signals of the inflammasome. Moreover, treatment with Cf-02 significantly inhibited secretion of IL-1β in lipopolysaccharide-stimulated macrophages, but this effect was abolished by autophagy induction. These results recommend Cf-02 as a promising drug candidate for the serious renal conditions associated with systemic lupus erythematosus. Future investigations should examine whether Cf-02 may also be therapeutic in other types of chronic kidney disease involving NLRP3 inflammasome-driven signaling.

Rituximab use as induction therapy for lupus nephritis: a systematic review

OBJECTIVE

Rituximab (RTX) has important usage in rheumatoid arthritis and vasculitis. There remains a need for more, better, and safer treatments for patients with lupus nephritis (LN). RTX has been trialed in such patients without definitive conclusions about its effectiveness. As a role for RTX has not been clearly established for LN, we carried out a systematic review and analysis.

METHODS

We identified 31 studies of RTX for class I-VI LN, and assessed complete renal response (CRR) and partial renal response (PRR) using criteria including serum creatinine, proteinuria, and urinary sediment. Due to differences in the pediatric presentation of the disease, studies focusing on pediatric patients were excluded.

RESULTS

One randomized controlled trial (RCT) showed superiority of RTX+cyclophosphamide (CYC) versus CYC alone (64% vs. 21% CRR and 19% vs. 36% PRR). Six prospective and retrospective studies utilizing RTX monotherapy found 66% CRR or PRR in all patients. Eleven studies that investigated RTX in combination with CYC or mycophenolate mofetil (MMF) also found 66% CRR or PRR in all patients. In total, the CRR for Caucasian, East Asian, and Hispanic patients were 77%, 38%, and 28%, respectively.

CONCLUSIONS

RTX appeared to benefit certain LN patients, but most studies were not randomized or properly controlled, were heterogeneous in design, subjects, and LN types, and were not comparable, and must therefore be interpreted cautiously. RTX alone may not deplete B cells sufficiently for the perturbations of LN. In addition, RTX may induce responses differently among patients of different ethnic and racial backgrounds. Furthermore, there were wide variations in the baseline characteristics of the patients, namely LN class, time course of disease, age, and prior immunosuppressive use. We suggest a prospective RCT in patients aged 18-65 years with class IV LN. Ideally, the patients would not have received prior immunosuppression and would better represent different ethnicities. The treatment groups would be RTX, RTX+belimumab, CYC, and MMF groups, with pulse-dose steroids during induction followed by maintenance steroids and MMF. The CRR and PRR would be assessed at 12 and 24 months. This or a similar study might clarify RTX's role in the treatment of LN.

Xenon blunts NF-κB/NLRP3 inflammasome activation and improves acute onset of accelerated and severe lupus nephritis in mice

Xenon, an inert anesthetic gas, is increasingly recognized to possess desirable properties including cytoprotective and anti-inflammatory effects. Here we evaluated the effects of xenon on the progression of lupus nephritis (LN) in a mouse model. A two hour exposure of either 70% xenon or 70% nitrogen balanced with oxygen was administered daily for five weeks to female NZB/W F1 mice that had been induced to develop accelerated and severe LN. Xenon treatment improved kidney function and renal histology, and decreased the renal expression of neutrophil chemoattractants, thereby attenuating glomerular neutrophil infiltration. The effects of xenon were mediated primarily by deceasing serum levels of anti-double stranded DNA autoantibody, inhibiting reactive oxygen species production, NF-κB/NLRP3 inflammasome activation, ICAM-1 expression, glomerular deposition of IgG and C3 and apoptosis, in the kidney; and enhancing renal hypoxia inducible factor 1-α expression. Proteomic analysis revealed that the treatment with xenon downregulated renal NLRP3 inflammasome-mediated cellular signaling. Similarly, xenon was effective in improving renal pathology and function in a spontaneous LN model in female NZB/W F1 mice. Thus, xenon may have a therapeutic role in treating LN but further studies are warranted to determine applicability to patients.

Rituximab in lupus nephritis: A non-systematic review

Lupus nephritis (LN) is a common and severe complication in patients with lupus. Current therapy is based on immunosuppressive drugs and glucocorticoids. Recently, rituximab has been proposed as an alternative treatment for LN. Rituximab is a monoclonal antibody directed against the CD20 antigen receptor on B cells. The aim of this review is to summarize all the available information about rituximab in LN. Eleven studies were found; three of them were observational studies (2 prospective and 1 retrospective) and eight were clinical trials (7 open-label studies and only 1 randomized controlled trial [RCT]). The evidence is insufficient to establish the role of rituximab in the treatment of LN. Results from the only RCT, which were negative, suggest a clinical benefit in black people. Further studies must confirm this hypothesis. Controlled clinical trials involving adaptive randomization are required to establish the real benefit of rituximab in LN.

The multifaceted aspects of refractory lupus nephritis

The term refractory lupus nephritis is generally used to indicate cases that do not respond to traditional treatment. However, the clinical presentation of lupus nephritis is variable and the time to response depends on the typology of the underlying renal syndrome. The criteria and the time for response are different in lupus patients with nephritic flares, in those with nephrotic syndrome, and in those with asymptomatic renal disease. In this paper, we will focus on the clinical characteristics, the consequences, and the possible therapeutic approaches for patients with different forms of refractory lupus nephritis, defined on the basis of renal syndrome at presentation.

Epidemiology and management of refractory lupus nephritis

Although the survival of patients with lupus nephritis (LN) has improved considerably in recent years, refractory LN appears in a substantial proportion of patients and, therefore, treatment of LN remains a real challenge today. We will use the term "refractory" LN, for those cases with none or partial response to first-line therapies. In this sense, numerous epidemiological factors, including racial, socioeconomic, histological and serological parameters, may influence treatment response and, therefore, may have an impact on the outcome of renal involvement. Initial conventional therapy will depend somewhat on these epidemiological factors. If this initial therapy fails, fortunately today we have alternative therapies that include the multitarget therapy and the use of biologics. Published evidence about these therapies is presented in this review. Important terms in the management of LN, such as the definition of complete response, partial response, sustained response and renal flare as well as the discrimination of different types of flare, are also discussed here according to the European consensus statement on the terminology used in the management of lupus glomerulonephritis.

Novel targets and new potential: developments in the treatment of inflammation in chronic kidney disease

BACKGROUND

Patients with chronic kidney disease (CKD) of all stages experience extremely high mortality, with cardiovascular causes accounting for about half of all their deaths. Traditional risk factors such as hypertension, hypercholesterolemia and diabetes mellitus cannot explain the excessively high cardiovascular mortality in CKD. Chronic inflammation is one of the novel risk factors that appear to contribute to the increased mortality seen in patients with CKD. Therapeutic interventions targeting chronic inflammation in CKD may lead to improved outcomes.

OBJECTIVES

To describe the role of inflammation in CKD and to review anti-inflammatory pharmacologic therapies that could have a role in its therapy.

METHODS

A review of the literature was carried out and expert opinion expressed.

RESULTS/CONCLUSION

Inflammation is a common and significant problem in CKD. There are currently no approved pharmacologic anti-inflammatory therapies in CKD but several agents are being studied in early clinical trials, while others could become viable alternatives in the future.