Emerging biological therapies for systemic lupus erythematosus

Cross-sectional study of plasma Axl, ferritin, IGFBP4 and sTNFR2 as biomarkers of disease activity in childhood-onset SLE: A study of the Pediatric Nephrology Research Consortium

OBJECTIVE

To evaluate the performance of 4 plasma protein markers for detecting disease activity in childhood-onset systemic lupus erythematosus (SLE) patients.

METHODS

Eighty-three consecutive pediatric patients fulfilling ≥4 ACR criteria for SLE and twenty-five healthy controls were prospectively recruited for serological testing of 4 protein markers identified by antibody-coated microarray screen, namely Axl, ferritin, IGFBP4 and sTNFR2. SLE disease activity was assessed using SLEDAI-2000 score. Fifty-seven patients had clinically active SLE (SLEDAI score ≥4, or having a flare).

RESULTS

The plasma concentrations of Axl and ferritin were significantly higher in patients with active SLE than inactive SLE. Plasma Axl levels were significantly higher in active renal versus active non-renal SLE patients. Levels of Axl, ferritin and IGFBP4 correlated significantly with SLEDAI scores. Levels of Axl, IFGBP4 and sTNFR2 inversely correlated with plasma complement C3 levels. Only plasma Axl and ferritin levels correlated with degree of proteinuria. These markers were more specific, but less sensitive, in detecting concurrent SLE activity than elevated anti-dsDNA antibody titer or decreased C3. Ferritin and IGFBP4 levels were more specific for concurrent active lupus nephritis than anti-dsDNA or C3. Plasma ferritin was the best monitor of global SLE activity, followed by C3 then Axl, while both Axl and C3 were best monitors of clinical lupus nephritis activity.

CONCLUSION

In childhood-onset SLE patients, plasma ferritin and Axl perform better than traditional yardsticks in identifying disease activity, either global or renal. The performance of these plasma markers should be explored further in longitudinal cohorts of SLE patients.

Naringenin mitigates autoimmune features in lupus-prone mice by modulation of T-cell subsets and cytokines profile

Naringenin is flavonoid mainly found in citrus fruits which has shown several biological properties. In this work, we evaluated the therapeutic potential of the flavonoid Naringenin. Five-month-old B6.MRL-Faslpr/J lupus-prone mice were administered daily orally with Naringenin for seven months. We showed that Naringenin treatment at 50 or 100 mg/kg inhibited the splenomegaly and decreased the levels of anti-nuclear and anti-dsDNA autoantibodies. Furthermore, a reduction in serum concentration of TNF-α, IFN-γ and IL-6 was observed in the mice provided with Naringenin. Interestingly, serum levels of IL-10 increased. Naringenin decreased the frequency and absolute numbers of splenic effector memory T cells. Additionally, in order to be able to evaluate whether Naringenin prevented kidney damage, twelve-week-old MRL/MpJ-Faslpr/J mice, an accelerated lupus model, were orally administered with Naringenin at 100 mg/kg for six weeks. Surprisingly, Naringenin treatment prevented kidney damage and reduced the development of fibrosis similar to cyclophosphamide group. Moreover, Naringenin treatment increased the percentage of regulatory T cells in this aggressive model of lupus. Together, these results suggest a potential ability of Naringenin to reduce the autoimmunity in lupus-prone mice by modulation of T-cell subsets and cytokines profile that mitigate the development of important lupus clinical manifestations.

Biologics in the Treatment of Lupus Erythematosus: A Critical Literature Review

Systemic lupus erythematosus (SLE) is a chronic autoimmune inflammatory disease affecting multiple organ systems that runs an unpredictable course and may present with a wide variety of clinical manifestations. Advances in treatment over the last decades, such as use of corticosteroids and conventional immunosuppressive drugs, have improved life expectancy of SLE sufferers. Unfortunately, in many cases effective management of SLE is still related to severe drug-induced toxicity and contributes to organ function deterioration and infective complications, particularly among patients with refractory disease and/or lupus nephritis. Consequently, there is an unmet need for drugs with a better efficacy and safety profile. A range of different biologic agents have been proposed and subjected to clinical trials, particularly dedicated to this subset of patients whose disease is inadequately controlled by conventional treatment regimes. Unfortunately, most of these trials have given unsatisfactory results, with belimumab being the only targeted therapy approved for the treatment of SLE so far. Despite these pitfalls, several novel biologic agents targeting B cells, T cells, or cytokines are constantly being evaluated in clinical trials. It seems that they may enhance the therapeutic efficacy when combined with standard therapies. These efforts raise the hope that novel drugs for patients with refractory SLE may be available in the near future. This article reviews the current biological therapies being tested in the treatment of SLE.

Serum 25-hydroxyvitamin D3 levels and flares of systemic lupus erythematosus: a longitudinal cohort analysis

The aim of this study is to evaluate the relationship between baseline serum 25-hydroxyvitamin D3 levels and SLE activity/flares over time. This is a longitudinal study of 276 patients who fulfilled ≥ 4 ACR criteria for SLE and recruited in the year 2011. Serum samples were collected at baseline and assayed for 25-hydroxyvitamin D3 at the end of a mean follow-up of 32.5 months. Participants were stratified into three groups according to baseline 25-hydroxyvitamin D3 levels: group I (< 15 ng/ml, deficiency), group II (15-30 ng/ml, insufficiency), and group III (> 30 ng/ml, adequate). Baseline and summated SLE disease activity index (SLEDAI) score over time and the annual incidence of lupus flares were compared among these groups. 25-hydroxyvitamin D3 levels of < 15, 15-30, and > 30 ng/ml were present in 26, 54, and 20% of the recruited patients, respectively. Group I had significantly higher baseline SLEDAI scores. After a follow-up of 32.5 ± 5.5 months, 153 mild/moderate and 91 severe flares developed. The mean summated SLEDAI was 3.2 ± 2.0 in group I, 2.4 ± 1.9 in group II and 2.7 ± 2.1 in group III patients (P = 0.02). The annual incidence of mild/moderate and severe flares was 0.26 ± 0.39 and 0.20 ± 0.45 (group I); 0.20 ± 0.33 and 0.09 ± 0.22 (group II); and 0.20 ± 0.32 and 0.14 ± 0.46 (group III), respectively (P > 0.05). In a subgroup of 73 patients who were clinically and serologically quiescent at baseline, a similar trend of more flares was observed in group I patients. Vitamin D deficiency was frequent in Chinese SLE patients and was associated with more active disease at baseline and over time, as well as a trend of more severe lupus flares.

Calcineurin inhibitors in systemic lupus erythematosus

The calcineurin inhibitors (CNIs) belong to a group of immunosuppressive agents that block T-cell activation through the suppression of the calcium/calcimodulin-dependent phosphatase calcineurin. Agents such as cyclosporine A (CSA) and tacrolimus (TAC) have long been used in patients with systemic lupus erythematosus (SLE). TAC is preferred to CSA in SLE because of the lower frequency of cosmetic, hypertensive and dyslipidemic adverse effects. Recent randomised controlled trials have demonstrated noninferiority of TAC to mycophenolate mofetil (MMF) or cyclophosphamide (CYC) for induction therapy of lupus nephritis. Low-dose combination of TAC and MMF has also been shown to outperform CYC pulses in inducing remission of lupus nephritis in Chinese patients. TAC does not affect fertility and is relatively safe in pregnancy. In SLE patients who are intolerant or refractory to conventional immunosuppressives, or where contraindications to other immunosuppressive agents exist, TAC is an alternative option. However, the therapeutic window of TAC is narrow, and drug level monitoring is required to ensure drug exposure and minimise toxicities. Current evidence of TAC in lupus nephritis is limited to 6 months, and its long-term safety as maintenance therapy of SLE is yet to be determined. Newer chemical analogues of CNIs, such as voclosporin, with less variable plasma concentration are being tested in lupus nephritis.

Spotlight on blisibimod and its potential in the treatment of systemic lupus erythematosus: evidence to date

B cells in general and BAFF (B cell activating factor of the tumor necrosis factor [TNF] family) in particular have been primary targets of recent clinical trials in systemic lupus erythematosus (SLE). In 2011, belimumab, a monoclonal antibody against BAFF, became the first biologic agent approved for the treatment of SLE. Follow-up studies have shown excellent long-term safety and tolerability of belimumab. In this review, we critically analyze blisibimod, a novel BAFF-neutralizing agent. In contrast to belimumab that only blocks soluble BAFF trimer but not soluble 60-mer or membrane BAFF, blisibimod blocks with high affinity all three forms of BAFF. Furthermore, blisibimod has a unique structure built on four high-affinity BAFF-binding peptides fused to the IgG1-Fc carrier. It was tested in phase I and II trials in SLE where it showed safety and tolerability. While it failed to reach the primary endpoint in a recent phase II trial, post hoc analysis demonstrated its efficacy in SLE patients with higher disease activity. Based on these results, blisibimod is currently undergoing phase III trials targeting this responder subpopulation of SLE patients. The advantage of blisibimod, compared to its competitors, lies in its higher avidity for BAFF, but a possible drawback may come from its immunogenic potential and the anticipated loss of efficacy over time.

Axl, Ferritin, Insulin-Like Growth Factor Binding Protein 2, and Tumor Necrosis Factor Receptor Type II as Biomarkers in Systemic Lupus Erythematosus

OBJECTIVE

To evaluate the performance of 4 serum protein markers for detecting concurrent clinical activity in patients with systemic lupus erythematosus (SLE).

METHODS

Consecutive patients who fulfilled ≥4 American College of Rheumatology classification criteria for SLE and healthy controls were recruited for serologic testing of 4 protein markers identified by antibody-coated microarray screen, namely Axl, ferritin, insulin-like growth factor binding protein 2 (IGFBP-2), and tumor necrosis factor receptor type II (TNFRII). SLE disease activity was assessed by the Safety of Estrogens in Lupus Erythematosus National Assessment version of the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) and physician's global assessment (PGA). Levels of these markers were correlated with SLEDAI scores, and their sensitivity and specificity for clinical SLE activity were determined.

RESULTS

A total of 94 SLE patients (98% women, mean ± SD age 28.7 ± 9.4 years, mean ± SD disease duration 5.4 ± 5.0 years) and 49 healthy controls were studied. Fifty-two patients had clinically active SLE (defined as SLEDAI score ≥6 or having a flare). The serum concentrations of Axl, ferritin, IGFBP-2, and TNFRII were significantly higher in patients with active SLE than in those with inactive SLE or in controls. The levels of these markers correlated strongly and significantly with anti-double stranded DNA (anti-dsDNA), C3, and clinical SLEDAI and PGA scores. These markers were more specific, but less sensitive, in detecting concurrent SLE activity than elevated anti-dsDNA or depressed C3. Levels of Axl, TNFRII, and IGFBP-2, but not ferritin, could differentiate active renal from active nonrenal or inactive SLE. The specificity of Axl and IGFBP-2 for concurrent active lupus nephritis was higher than anti-dsDNA or C3.

CONCLUSION

Serum proteomic markers are potentially useful for diagnosing SLE and monitoring disease activity. The performance of Axl and IGFBP-2 in lupus nephritis should be further explored in a longitudinal cohort of SLE patients.

Hydroxychloroquine Serum Concentrations and Flares of Systemic Lupus Erythematosus: A Longitudinal Cohort Analysis

OBJECTIVE

To study the relationship between serum hydroxychloroquine (HCQ) concentrations and flares of systemic lupus erythematosus (SLE) in a longitudinal cohort of patients.

METHODS

Patients who fulfilled ≥4 American College of Rheumatology classification criteria for SLE and had been treated with HCQ for >6 months were studied. Blood was assayed for HCQ levels by tandem mass spectrometry. Patients were serially assessed for disease activity, using the Safety of Estrogens in Lupus Erythematosus National Assessment (SELENA) version of the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) and flares (SELENA flares instrument). Comparison of the mean summated SLEDAI scores over time and rates of flares in groups with different HCQ levels was performed by the Kruskal-Wallis test.

RESULTS

A total of 276 SLE patients were studied (93% women, mean ± SD age 41.0 ± 13.8 years). The proportion of patients with HCQ levels <10 (total noncompliance), 10-500 (subtherapeutic), and >500 ng/ml (therapeutic) was 11%, 77%, and 12%, respectively. HCQ levels correlated significantly with the prescribed dose but not with body weight or renal function. The prescribed HCQ dose also correlated significantly with baseline SLEDAI scores, indicating that higher doses were used for more active manifestations. After a mean ± SD observation period of 32.5 ± 5.5 months, the mean summated SLEDAI score and the incidence of SLE flares was not statistically different among patients with different baseline HCQ levels. In a subgroup of 73 patients with serologic and clinical remission and having therapeutic HCQ levels, a trend of lower disease activity and fewer incidences of flares was observed.

CONCLUSION

Noncompliance and subtherapeutic serum HCQ levels were seen frequently in these SLE patients, which was partly due to the low prescribed dose. In patients in remission, higher HCQ concentrations were associated with a trend showing fewer flares over time.

Con: Cyclophosphamide for the treatment of lupus nephritis

Kidney involvement is a major determinant for morbidity and mortality in patients with systemic lupus erythematosus. The treatment target of lupus renal disease is to induce and maintain remission and to minimize disease or treatment-related comorbidities. Cyclophosphamide (CYC), in conjunction with glucocorticoids, has conventionally been used for the initial treatment of lupus nephritis. However, the major concerns of CYC are its toxicities, such as infertility, urotoxicity and oncogenicity, which are particularly relevant in women of childbearing age. As a result, maintenance therapy of lupus nephritis with an extended course of CYC pulses has largely been replaced by other immunosuppressive agents such as mycophenolate mofetil (MMF) and azathioprine. Recent randomized controlled trials have demonstrated non-inferiority of MMF to pulse CYC as induction therapy of lupus nephritis. Although MMF as induction-maintenance therapy has been increasingly used in lupus nephritis, its efficacy in the long-term preservation of renal function remains to be elucidated. MMF is not necessarily less toxic than CYC. Meta-analyses of clinical trials show similar incidence of infective complications and gastrointestinal adverse events in both MMF- and CYC-based regimens. However, considering the reduction in gonadal toxicity and the risk of oncogenicity, MMF may be used as first-line therapy of lupus nephritis. Tacrolimus (TAC) has recently been shown to be equivalent to either MMF or CYC for inducing remission of lupus nephritis and may be considered as another non-CYC alternative. Combined low-dose MMF and TAC appears to be more effective than CYC pulses in Chinese patients with lupus nephritis and has the potential to replace the more toxic CYC regimens in high-risk patients. Currently, CYC still plays an important role in the management of lupus nephritis patients with impaired or rapidly deteriorating renal function, crescentic glomerulonephritis or as salvage therapy for recalcitrant disease.

Towards new avenues in the management of lupus glomerulonephritis

Renal involvement in systemic lupus erythematosus (SLE) carries substantial morbidity and mortality. Conventional immunosuppressive agents (cyclophosphamide and azathioprine) have suboptimal efficacy and substantial toxicity. Mycophenolate mofetil has emerged as an alternative agent for both induction and maintenance therapy in lupus nephritis because of its reduced gonadal toxicity, despite its failure to demonstrate superiority over cyclophosphamide in pivotal studies. The calcineurin inhibitor tacrolimus has equivalent efficacy to cyclophosphamide and mycophenolate mofetil for inducing remission of lupus nephritis. Although rituximab has shown promise in refractory lupus nephritis, combining rituximab with mycophenolate mofetil as initial therapy offers no additional benefit. Considerable interethnic variation is evident in the efficacy and tolerability of the various immunosuppressive regimens, which necessitates individualized treatment and comparison of the efficacy of new regimens across different ethnic groups. For example, low-dose combinations of tacrolimus and mycophenolate mofetil seem to be more effective than pulse cyclophosphamide as induction therapy in Chinese patients. The same regimen has also been used successfully to treat refractory proliferative and membranous lupus nephritis in patients of various ethnic groups. Finally, novel serum and urinary biomarkers are being validated for diagnosis, prognostic stratification and early recognition of flares in lupus nephritis.

Decrease of Functional Activated T and B Cells and Treatment of Glomerulonephitis in Lupus-Prone Mice Using a Natural Flavonoid Astilbin

Treatment of systemic lupus erythematosus (SLE), a chronic inflammatory disease, involves the long-term use of immunosuppressive agents with significant side effects. New therapeutic approaches are being explored to find better treatment possibilities. In this study, age-matched female MRL/lpr mice were treated orally with a natural flavonoid astilbin. Astilbin administration started either at week 8 or week 12 of age though week 20. In the early treatment regimen, the treatment with astilbin reduced splenomegaly / lymphomegaly, autoantibody production and ameliorated lupus nephitis. Several serum cytokines were significantly decreased upon treatment including IFN-g, IL-17A, IL-1b, TNF-a and IL-6. Both spleen CD44^hiCD62L^lo activated T cells and CD138⁺B220^- plasma cells greatly declined. Furthermore, astilbin treatment resulted in decreased mitochondrial membrane potential in activated T cells and downregulated expression of the co-stimulatory molecules CD80 and CD86 on LPS stimulated B cells. Similar but less profound effectiveness was observed in the mice with established disease in the late treatment regimen. These results indicate that the natural product astilbin can mitigate disease development in lupus-prone mice by decreasing functional activated T and B cells.

Validation of the LupusPRO in Chinese patients from Hong Kong with systemic lupus erythematosus

OBJECTIVE

LupusPRO is a disease-targeted, patient-reported outcome (PRO) measure that was developed and validated for assessment of quality of life in US patients with systemic lupus erythematosus (SLE). We present results of adapting the LupusPRO into Chinese and testing its psychometric properties in Chinese patients with SLE.

METHODS

LupusPRO was translated into "traditional" Chinese, followed by pretesting among native Cantonese Chinese speakers. The translation version was revised based on the feedback obtained. The Chinese language LupusPRO tool was administered along with a generic PRO tool (the Short Form 36 health survey [SF-36]) to ethnic Chinese SLE patients. At the same time, demographic information, clinical data, disease activity (Safety of Estrogens in Lupus Erythematosus National Assessment [SELENA] version of the Systemic Lupus Erythematosus Disease Activity Index [SLEDAI]), and damage (Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index [SDI]) were obtained. We performed confirmatory factor analysis of the Chinese LupusPRO and evaluated internal consistency reliability, as well as convergent and criterion validity.

RESULTS

Among the 463 SLE patients (95% women) with a mean ± SD age of 42.3 ± 13.5 years, the mean ± SD physician global assessment score was 0.48 ± 0.45, the mean ± SD SELENA-SLEDAI score was 2.9 ± 3.0, and the mean ± SD SDI score was 0.7 ± 1.2. Results of factor analysis conformed to the original LupusPRO model with only minor modifications. The reliability of the LupusPRO domains ranged from 0.60-0.94. LupusPRO domains had correlations as expected with the corresponding SF-36 domains. A significant but weak correlation with disease activity was noted for criterion validity as expected.

CONCLUSION

The Chinese language LupusPRO has fair psychometric properties and may be used in SLE clinical trials.