Phase II randomised trial of type I interferon inhibitor anifrolumab in patients with active lupus nephritis.

OBJECTIVE: To assess the efficacy and safety of the type I interferon receptor antibody, anifrolumab, in patients with active, biopsy-proven, Class III/IV lupus nephritis. METHODS: This phase II double-blinded study randomised 147 patients (1:1:1) to receive monthly intravenous anifrolumab basic regimen (BR, 300 mg), intensified regimen (IR, 900 mg ×3, 300 mg thereafter) or placebo, alongside standard therapy (oral glucocorticoids, mycophenolate mofetil). The primary endpoint was change in baseline 24-hour urine protein-creatinine ratio (UPCR) at week (W) 52 for combined anifrolumab versus placebo groups. The secondary endpoint was complete renal response (CRR) at W52. Exploratory endpoints included more stringent CRR definitions and sustained glucocorticoid reductions (≤7.5 mg/day, W24-52). Safety was analysed descriptively. RESULTS: Patients received anifrolumab BR (n=45), IR (n=51), or placebo (n=49). At W52, 24-hour UPCR improved by 69% and 70% for combined anifrolumab and placebo groups, respectively (geometric mean ratio=1.03; 95% CI 0.62 to 1.71; p=0.905). Serum concentrations were higher with anifrolumab IR versus anifrolumab BR, which provided suboptimal exposure. Numerically more patients treated with anifrolumab IR vs placebo attained CRR (45.5% vs 31.1%), CRR with UPCR ≤0.5 mg/mg (40.9% vs 26.7%), CRR with inactive urinary sediment (40.9% vs 13.3%) and sustained glucocorticoid reductions (55.6% vs 33.3%). Incidence of herpes zoster was higher with combined anifrolumab vs placebo (16.7% vs 8.2%). Incidence of serious adverse events was similar across groups. CONCLUSION: Although the primary endpoint was not met, anifrolumab IR was associated with numerical improvements over placebo across endpoints, including CRR, in patients with active lupus nephritis. TRIAL REGISTRATION NUMBER: NCT02547922.

Treat-to-Target in Lupus Nephritis. What is the Role of the Repeat Kidney Biopsy?

Kidney involvement, termed lupus nephritis (LN), develops in 35-60% of patients with systemic lupus erythematosus, often early during the disease course. When not treated promptly and efficiently, LN may lead to rapid and severe loss of kidney function, being the reason why it is considered one of the most severe lupus manifestations. Despite improved pharmacotherapy, 5-20% of LN patients develop end-stage kidney disease within ten years from the LN diagnosis. While the principal ground of LN therapy is prevention of renal function worsening, resembling a race against nephron loss, consensual agreement upon outcome measures and clinically meaningful short- and long-term targets of LN therapy have yet to be determined. Literature points to the importance of inclusion of tissue-based approaches in the determination of those targets, and evidence accumulates regarding the importance of per-protocol repeat kidney biopsies in the evaluation of the initial phase of therapy and prediction of long-term renal prognosis. The latter leads to the hypothesis that the information gleaned from repeat biopsies may contribute to optimised therapeutic decision making, and, therefore, increased probability to attain complete renal response in the short term, and a more favourable renal prognosis within a longer prospect. The multinational project ReBioLup was recently designed to serve as a key contributor to form evidence about the role of per-protocol repeat biopsies in a randomised fashion and aspires to unify the global LN community towards improved kidney and patient survival.

From sequential to combination and personalised therapy in lupus nephritis: moving towards a paradigm shift?

The current treatment paradigm in lupus nephritis consists of an initial phase aimed at inducing remission and a subsequent remission maintenance phase. With this so-called sequential treatment approach, complete renal response is achieved in a disappointing proportion of 20-30% of the patients within 6-12 months, and 5-20% develop end-stage kidney disease within 10 years. Treat-to-target approaches are detained owing to uncertainty as to whether the target should be determined based on clinical, histopathological, or immunopathological features. Until reliable non-invasive biomarkers exist, tissue-based evaluation remains the gold standard, necessitating repeat kidney biopsies for treatment evaluation and therapeutic decision-making. In this viewpoint, we discuss the pros and cons of voclosporin and belimumab as add-on agents to standard therapy, the first drugs to be licenced for lupus nephritis after recent successful randomised phase III clinical trials. We also discuss the prospect of obinutuzumab and anifrolumab, also on top of standard immunosuppression, currently tested in phase III trials after initial auspicious signals. Undoubtably, the treatment landscape in lupus nephritis is changing, with combination treatment regimens challenging the sequential concept. Meanwhile, the enrichment of the treatment armamentarium shifts the need from lack of therapies to the challenge of how to select the right treatment for the right patient. This has to be addressed in biomarker surveys along with tissue-level mapping of inflammatory phenotypes, which will ultimately lead to person-centred therapeutic approaches. After many years of trial failures, we may now anticipate a heartening future for patients with lupus nephritis.

Absence of renal remission portends poor long-term kidney outcome in lupus nephritis.

BACKGROUND: The very long-term consequences of absence of remission in lupus nephritis (LN) remain understudied. METHODS: In this retrospective analysis, we studied a selected cohort of 128 patients with biopsy-proven class III, IV or V incident LN followed for a median period of 134 months (minimum 25). Remission was defined as a urine protein to creatinine (uP:C) ratio <0.5 g/g and a serum creatinine value <120% of baseline. Renal relapse was defined as the reappearance of a uP:C >1 g/g, leading to a repeat kidney biopsy and treatment change. Poor long-term renal outcome was defined as the presence of chronic kidney disease (CKD). RESULTS: Twenty per cent of patients never achieved renal remission. Their baseline characteristics did not differ from those who did. Absence of renal remission was associated with a threefold higher risk of CKD (48% vs 16%) and a 10-fold higher risk of end-stage renal disease (20% vs 2%). Patients achieving early remission had significantly higher estimated glomerular filtration rate (eGFR) at last follow-up compared with late remitters. Accordingly, patients with CKD at last follow-up had statistically longer time to remission. Among patients who achieved remission, 32% relapsed, with a negative impact on renal outcome, that is, lower eGFR values and higher proportion of CKD (33% vs 8%). CONCLUSION: Early remission should be achieved to better preserve long-term renal function.

Quality indicators for systemic lupus erythematosus based on the 2019 EULAR recommendations: development and initial validation in a cohort of 220 patients.

BACKGROUND: Quality of care is receiving increased attention in systemic lupus erythematosus (SLE). We developed quality indicators (QIs) for SLE based on the 2019 update of European League Against Rheumatism recommendations. METHODS: A total of 44 candidate QIs corresponding to diagnosis, monitoring and treatment, were independently rated for validity and feasibility by 12 experts and analysed by a modified Research and Development Corporation/University of California Los Angeles model. Adherence to the final set of QIs and correlation with disease outcomes (flares, hospitalisations and organ damage) was tested in a cohort of 220 SLE patients with a median monitoring of 2 years (IQR 2-4). RESULTS: The panel selected a total of 18 QIs as valid and feasible. On average, SLE patients received 54% (95% CI 52.3% to 56.2%) of recommended care, with adherence ranging from 44.7% (95% CI 40.8% to 48.6%) for diagnosis-related QIs to 84.3% (95% CI 80.6% to 87.5%) for treatment-related QIs. Sustained remission or low disease activity were achieved in 26.8% (95% CI 21.1% to 33.2%). Tapering of prednisone dose to less than 7.5 mg/day was achieved in 93.6% (95% CI 88.2% to 97.0%) while 73.5% (95% CI 66.6% to 79.6%) received the recommended hydroxychloroquine dose. Higher adherence to monitoring-related QIs was associated with reduced risk for a composite adverse outcome (flare, hospitalisation or damage accrual) during the last year of observation (OR 0.97 per 1% adherence rate, 95% CI 0.96 to 0.99). CONCLUSION: We developed QIs for assessing and improving the care of SLE patients. Initial real-life data suggest face validity, but a variable degree of adherence and a need for further improvement.

Management of Lupus Nephritis.

Lupus nephritis (LN) is a frequent and severe manifestation of systemic lupus erythematosus. The main goal of the management of LN is to avoid chronic kidney disease (CKD). Current treatment strategies remain unsatisfactory in terms of complete renal response, prevention of relapses, CKD, and progression to end-stage kidney disease. To improve the prognosis of LN, recent data suggest that we should (i) modify our treat-to-target approach by including, in addition to a clinical target, a pathological target and (ii) switch from conventional sequential therapy to combination therapy. Here, we also review the results of recent controlled randomized trials.

Per-protocol repeat kidney biopsy portends relapse and long-term outcome in incident cases of proliferative lupus nephritis.

OBJECTIVES: In patients with LN, clinical and histological responses to treatment have been shown to be discordant. We investigated whether per-protocol repeat kidney biopsies are predictive of LN relapses and long-term renal function impairment. METHODS: Forty-two patients with incident biopsy-proven active proliferative (class III/IV±V) LN from the database of the UCLouvain were included in this retrospective study. Per-protocol repeat biopsies were performed after a median [interquartile range (IQR)] time of 24.3 (21.3-26.2) months. The National Institutes of Health activity index (AI) and chronicity index (CI) scores were assessed in all biopsies. RESULTS: Despite a moderate correlation between urinary protein/creatinine ratios (UPCR) and AI scores at repeat biopsy (r = 0.48; P = 0.001), 10 patients (23.8%) with UPCR < 1.0 g/g still had a high degree of histological activity (AI > 3). High AI scores (continuous) in repeat biopsies were associated with an increased probability and/or shorter time to renal relapse (n = 11) following the repeat biopsy [hazard ratio (HR) = 1.2, 95% CI: 1.1, 1.3; P = 0.007], independently of proteinuria levels. High CI scores (continuous) in repeat biopsies were associated with a sustained increase in serum creatinine levels corresponding to ≥120% of the baseline value (HR = 1.8, 95% CI: 1.1, 2.9; P = 0.016) through a median (IQR) follow-up time of 131.5 (73.8-178.2) months, being also the case for acute tubulointerstitial inflammation and interstitial fibrosis/tubular atrophy in repeat but not baseline biopsies. CONCLUSION: Our results highlight the usefulness of per-protocol repeat biopsies, herein performed after a median time of 24 months from baseline, as an integral part of the treatment evaluation, also in patients showing adequate clinical response.

Tapering of biological antirheumatic drugs in rheumatoid arthritis patients is achievable and cost-effective in daily clinical practice: data from the Brussels UCLouvain RA Cohort.

BACKGROUND/PURPOSE: Studies have demonstrated that rheumatoid arthritis (RA) patients who achieve low disease activity or remission are able to taper biological disease-modifying antirheumatic drugs (bDMARDs). The aim of this study was to evaluate the proportion of patients in whom bDMARDs can be tapered in daily practice and to analyse the characteristics of these patients. Other objectives were to analyse which bDMARDs are more suitable for dose reduction and the cost savings. RESULTS: Data from 332 eligible RA patients from our Brussels UCLouvain cohort were retrospectively analysed; 140 patients (42.1%) received a tapered regimen, and 192 received stable doses of bDMARDs. The age at diagnosis (43.1 vs 38.7 years, p = 0.04), health assessment questionnaire (HAQ) score (1.3 vs 1.5, p = 0.048), RF positivity rate (83.3 vs 72.9%, p = 0.04) and disease duration at the time of bDMARD introduction (9.7 vs 12.1 years, p = 0.034) were significantly different between the reduced-dose and stable-dose groups. Interestingly, relatively more patients receiving a tapered dose were treated with a combination of bDMARDs and methotrexate (MTX) (86.7% vs 73.8%, p = 0.005). In our cohort, anti-TNF agents were the most commonly prescribed medications (68%). Only 15 patients experienced a flare during follow-up. Adalimumab, etanercept and rituximab were the most common bDMARDs in the reduced-dose group and were associated with the most important reductions in annual cost. CONCLUSION: In daily practice, tapering bDMARDs in RA patients who have achieved low disease activity or remission is an achievable goal in a large proportion of patients, thereby reducing potential side effects and annual drug-associated costs. The combination of bDMARDs with MTX could improve the success of dose reduction attempts. TRIAL REGISTRATION: This retrospective non-interventional study was retrospectively registered with local ethics approval.

2019 Update of the Joint European League Against Rheumatism and European Renal Association-European Dialysis and Transplant Association (EULAR/ERA-EDTA) recommendations for the management of lupus nephritis.

OBJECTIVE: To update the 2012 EULAR/ERA-EDTA recommendations for the management of lupus nephritis (LN). METHODS: Following the EULAR standardised operating procedures, a systematic literature review was performed. Members of a multidisciplinary Task Force voted independently on their level of agreeement with the formed statements. RESULTS: The changes include recommendations for treatment targets, use of glucocorticoids and calcineurin inhibitors (CNIs) and management of end-stage kidney disease (ESKD). The target of therapy is complete response (proteinuria <0.5-0.7 g/24 hours with (near-)normal glomerular filtration rate) by 12 months, but this can be extended in patients with baseline nephrotic-range proteinuria. Hydroxychloroquine is recommended with regular ophthalmological monitoring. In active proliferative LN, initial (induction) treatment with mycophenolate mofetil (MMF 2-3 g/day or mycophenolic acid (MPA) at equivalent dose) or low-dose intravenous cyclophosphamide (CY; 500 mg × 6 biweekly doses), both combined with glucocorticoids (pulses of intravenous methylprednisolone, then oral prednisone 0.3-0.5 mg/kg/day) is recommended. MMF/CNI (especially tacrolimus) combination and high-dose CY are alternatives, for patients with nephrotic-range proteinuria and adverse prognostic factors. Subsequent long-term maintenance treatment with MMF or azathioprine should follow, with no or low-dose (<7.5 mg/day) glucocorticoids. The choice of agent depends on the initial regimen and plans for pregnancy. In non-responding disease, switch of induction regimens or rituximab are recommended. In pure membranous LN with nephrotic-range proteinuria or proteinuria >1 g/24 hours despite renin-angiotensin-aldosterone blockade, MMF in combination with glucocorticoids is preferred. Assessment for kidney and extra-renal disease activity, and management of comorbidities is lifelong with repeat kidney biopsy in cases of incomplete response or nephritic flares. In ESKD, transplantation is the preferred kidney replacement option with immunosuppression guided by transplant protocols and/or extra-renal manifestations. Treatment of LN in children follows the same principles as adult disease. CONCLUSIONS: We have updated the EULAR recommendations for the management of LN to facilitate homogenization of patient care.

Prediction of prognosis and renal outcome in lupus nephritis.

Lupus nephritis (LN) is a severe manifestation of SLE, characterised by subendothelial and/or subepithelial immune complex depositions in the afflicted kidney, resulting in extensive injury and nephron loss during the acute phase and eventually chronic irreversible damage and renal function impairment if not treated effectively. The therapeutic management of LN has improved during the last decades, but the imperative need for consensual outcome measures remains. In order to design trials with success potentiality, it is important to define clinically important short-term and long-term targets of therapeutic and non-therapeutic intervention. While it is known that early response to treatment is coupled with favourable renal outcomes, early predictors of renal function impairment are lacking. The information gleaned from kidney biopsies may provide important insights in this direction. Alas, baseline clinical and histopathological information has not been shown to be informative. By contrast, accumulating evidence of pronounced discrepancies between clinical and histopathological outcomes after the initial phase of immunosuppression has prompted investigations of the potential usefulness of per-protocol repeat kidney biopsies as an integral part of treatment evaluation, including patients showing adequate clinical response. This approach appears to have merit. Hopefully, clinical, molecular or genetic markers that reliably reflect kidney histopathology and portend the long-term prognosis will be identified. Novel non-invasive imaging methods and employment of the evolving artificial intelligence in pattern recognition may also be helpful towards these goals. The molecular and cellular characterisation of SLE and LN will hopefully result in novel therapeutic modalities, maybe new taxonomy perspectives, and ultimately personalised management.

Intrarenal activation of adaptive immune effectors is associated with tubular damage and impaired renal function in lupus nephritis.

OBJECTIVES: Chronic renal impairment remains a feared complication of lupus nephritis (LN). The present work aimed at identifying mechanisms and markers of disease severity in renal tissue samples from patients with LN. METHODS: We performed high-throughput transcriptomic studies (Illumina HumanHT-12 v4 Expression BeadChip) on archived kidney biopsies from 32 patients with LN and eight controls (pretransplant donors). Histological staging (glomerular and tubular scores) and immunohistochemistry experiments were performed on the same and on a replication set of 37 LN kidney biopsy samples. RESULTS: A group of LN samples was identified by unsupervised clustering studies based on their gene expression features, that is, the overexpression of transcripts involved in antigen presentation, T and B cell activation. These samples were characterised by a significantly lower estimated glomerular filtration rate (eGFR) at the time of biopsy (T0) compared with the other systemic lupus erythematosus samples. Yet, apparent disease duration at T0, double-stranded DNA antibody titres at T0 and other relevant characteristics (serum C3, proteinuria, histological scores, numbers of previous flares) were not different between groups.Immunohistochemistry studies confirmed the association between interstitial infiltration by adaptive immune effectors and decreased renal function in the same and in a replication group of LN kidney biopsies. This was associated with transcriptomic, histological and immunohistochemical evidence of renal tubular cell involvement. CONCLUSION: Interstitial infiltration of LN kidney biopsies by adaptive immune effectors is associated with impaired renal tubular cell function and decreased eGFR. These results open new perspectives in evaluating and treating patients with LN, focusing on intrarenal mechanisms of immune cell activation.

Higher expression of TNFα-induced genes in the synovium of patients with early rheumatoid arthritis correlates with disease activity, and predicts absence of response to first line therapy.

BACKGROUND: IL6-related T cell activation and TNFα-dependent cell proliferation are major targets of therapy in the RA synovium. We investigated whether expression of these pathways in RA synovial biopsies is associated with disease activity and response to therapy. METHOD: Correlation and gene set enrichment studies were performed using gene expression profiles from RA synovial biopsies. Immunostaining experiments of GADD45B and PDE4D were performed on independent additional sets of early untreated RA samples, obtained in two different centers by needle-arthroscopy or US-guided biopsies. RESULTS: In 65 RA synovial biopsies, transcripts correlating with disease activity were strongly enriched in TNFα-induced genes. Out of the individual variables used in disease-activity scores, tender joint count, swollen joint count and physician's global assessment, but not CRP or patient's global assessment displayed a similar correlation with the expression of TNFα-dependent genes. In addition, TNFα-induced genes were also significantly enriched in transcripts over-expressed in synovial biopsy samples obtained from poor-responders to methotrexate or tocilizumab, prior to initiation of therapy. GADD45B (induced by TNFα in monocytes) and PDE4D (induced by TNFα in FLS) immunostaining was significantly higher in overall poor-responders to therapy in 46 independent baseline samples obtained from early untreated RA patients prior to initiation of therapy. GADD45B (but not PDE4D) immunostaining was significantly higher in the sub-group of patients with poor-response to methotrexate therapy, and this was confirmed in another population of methotrexate-treated patients. CONCLUSION: Higher expression of TNFα-induced transcripts in early RA synovitis is associated with higher disease activity, and predicts poor response to first-line therapy. That over-expression of TNFα-induced genes predicts poor-response to therapy regardless of the drug administered, indicates that this molecular signature is associated with disease severity, rather than with specific pathways of escape to therapy.

Global molecular effects of tocilizumab therapy in rheumatoid arthritis synovium.

OBJECTIVE: To investigate the global molecular effects of tocilizumab (TCZ) in comparison with methotrexate (MTX) treatment in synovial biopsy tissue obtained from patients with previously untreated rheumatoid arthritis (RA) before therapy (T0) and 12 weeks after the initiation of therapy (T12), and to compare the results with previous gene expression data obtained in synovial biopsy tissue from adalimumab (ADA)- and rituximab (RTX)-treated patients with RA. METHODS: Paired synovial biopsy samples were obtained at T0 and T12 from the affected knee of TCZ-treated RA patients and MTX-treated RA patients. Gene expression studies were performed using GeneChip Human Genome U133 Plus 2.0 microarrays, and confirmatory quantitative real-time reverse transcription-polymerase chain reaction experiments were performed on selected transcripts. The effects of TCZ and MTX on synovial cell populations and histologic characteristics were assessed by immunohistochemistry. RESULTS: Gene expression studies showed that blockade of the interleukin-6 receptor (IL-6R) gene (IL6R) using TCZ induced a significant decrease in the expression of numerous chemokine and T cell activation genes in the RA synovium. These effects strongly correlated with the molecular effects of MTX and RTX therapy on RA synovial tissue, but differed from the molecular changes induced by ADA (decreased expression of genes involved in cell proliferation). CONCLUSION: The molecular similarities between the effects of TCZ, RTX, and MTX therapies in the RA synovium indicate that B cell- and IL-6-dependent pathways play synergistic roles in the pathogenesis of the disease, in particular through activation of T cell responses. Moreover, these results open perspectives for the individualization of therapeutic decisions, based on a better knowledge of the synovial molecular effects of each type of RA therapy.

Serum soluble interleukin 7 receptor is strongly associated with lupus nephritis in patients with systemic lupus erythematosus.

BACKGROUND: The soluble form of the interleukin 7 receptor (sIL-7R) is produced by fibroblasts after stimulation with proinflammatory cytokines. Increased sIL-7R serum and synovial fluid levels were recently demonstrated in patients with rheumatoid arthritis. OBJECTIVES: To investigate whether sIL-7R production is dysregulated in systemic lupus erythematosus (SLE), and whether this correlates with disease activity. METHODS: Serum and urine sIL-7R concentrations were measured by ELISA, and sIL-7R quantitative PCR (qPCR) studies were performed in peripheral blood mononuclear cells (PBMCs). IL-7R, tumour necrosis factor α (TNFα), IL-1ß and IL-17 immunostainings were performed on kidney sections. RESULTS: sIL-7R concentrations were significantly higher in SLE sera than in controls, and correlated with SLE Disease Activity Index (SLEDAI) scores. Accordingly, serum sIL-7R levels were strongly raised in patients with nephritis. Moreover in patients with lupus nephritis, serum sIL-7R decreased upon treatment. sIL-7R gene expression in PBMCs was similar in patients with lupus nephritis and controls. By contrast, abundant perivascular IL-7R expression was seen in SLE kidney biopsy specimens, which was associated with expression of TNFα in the surrounding tissue. CONCLUSIONS: Our data indicate that sIL-7R is a marker of SLE disease activity, especially nephritis. In contrast to conventional disease activity markers, sIL-7R is not produced by immune cells, but might instead reflect activation of tissue cells in the target organ.

Joint European League Against Rheumatism and European Renal Association-European Dialysis and Transplant Association (EULAR/ERA-EDTA) recommendations for the management of adult and paediatric lupus nephritis.

OBJECTIVES: To develop recommendations for the management of adult and paediatric lupus nephritis (LN). METHODS: The available evidence was systematically reviewed using the PubMed database. A modified Delphi method was used to compile questions, elicit expert opinions and reach consensus. RESULTS: Immunosuppressive treatment should be guided by renal biopsy, and aiming for complete renal response (proteinuria <0.5 g/24 h with normal or near-normal renal function). Hydroxychloroquine is recommended for all patients with LN. Because of a more favourable efficacy/toxicity ratio, as initial treatment for patients with class III-IV(A) or (A/C) (±V) LN according to the International Society of Nephrology/Renal Pathology Society 2003 classification, mycophenolic acid (MPA) or low-dose intravenous cyclophosphamide (CY) in combination with glucocorticoids is recommended. In patients with adverse clinical or histological features, CY can be prescribed at higher doses, while azathioprine is an alternative for milder cases. For pure class V LN with nephrotic-range proteinuria, MPA in combination with oral glucocorticoids is recommended as initial treatment. In patients improving after initial treatment, subsequent immunosuppression with MPA or azathioprine is recommended for at least 3 years; in such cases, initial treatment with MPA should be followed by MPA. For MPA or CY failures, switching to the other agent, or to rituximab, is the suggested course of action. In anticipation of pregnancy, patients should be switched to appropriate medications without reducing the intensity of treatment. There is no evidence to suggest that management of LN should differ in children versus adults. CONCLUSIONS: Recommendations for the management of LN were developed using an evidence-based approach followed by expert consensus.

Repeat kidney biopsies fail to detect differences between azathioprine and mycophenolate mofetil maintenance therapy for lupus nephritis: data from the MAINTAIN Nephritis Trial.

BACKGROUND: In the MAINTAIN Nephritis Trial, azathioprine (AZA) and mycophenolate mofetil (MMF) were compared as maintenance immunosuppressive treatment of proliferative lupus nephritis (LN) after a short-course of intravenous cyclophosphamide. Here, we compare the pathological findings on repeat kidney biopsies between the two groups. METHODS: Per protocol, repeat renal biopsies were obtained in 30 patients (16 AZA and 14 MMF) at 2 years (±6 months). Baseline and follow-up biopsies were graded according to the International Society of Nephrology/Renal Pathological Society (ISN/RPS) classification. The activity and chronicity indices (AI, CI) were calculated using two different semiquantitative scoring systems (Morel-Maroger and National Institutes of Health). Statistics were performed by non-parametric tests. RESULTS: The clinical characteristics of the 30 re-biopsied patients only marginally differ from the entire MAINTAIN cohort (105 patients). Clinical baseline and follow-up characteristics of AZA- and MMF-treated re-biopsied patients did not differ. Time (SD) to repeat renal biopsy was 25.0 (2.0) and 26.5 (3.3) months in AZA and MMF patients, respectively. More patients had normal renal biopsies or Classes I/II/V LN at follow-up compared to baseline and conversely, less patients had Class IV LN at follow-up. In both groups, the AI statistically decreased at follow-up compared to baseline, while the CI slightly, but significantly, increased. No differences could be detected between the groups. CONCLUSION: Centralized pathological analyses, including ISN/RPS classification and comparisons of AI/CI, failed to find differences between MMF and AZA at 2 years, a result well in line with the absence of difference in long-term clinical outcome reported elsewhere.