Renal Recovery for Patients with ANCA-Associated Vasculitis and Low eGFR in the ADVOCATE Trial of Avacopan

Complement as a major mediator of ANCA vasculitis and a target for precision therapy

INTRODUCTION

Complement was long thought not to be involved in ANCA vasculitis pathogenesis until studies in murine models demonstrated its central role. The current theory is ANCA-activated neutrophils degranulate and release factors that activate complement, which, in turn, recruits more neutrophils and causes an inflammatory amplification loop that results in the vascular inflammation characteristic of disease. Targeting this amplification loop through complement inhibition has proven to be effective in ANCA vasculitis treatment.

AREAS COVERED

A PubMed search was conducted using key terms 'ANCA vasculitis' AND 'complement system.' We review findings from experimental mouse models, in vitro studies, and human ANCA vasculitis that support a role for complement activation in disease pathogenesis. We also summarize results from pivotal clinical studies demonstrating the safety and efficacy of complement inhibition in ANCA vasculitis treatment.

EXPERT OPINION

While complement activation is undoubtedly involved in ANCA vasculitis pathogenesis, less clear is whether measuring complement activation markers can reliably assess disease activity, predict those who will benefit from complement-targeting therapy, or identify patients in stable remission and able to stop therapy. Better understanding the clinical implications of complement activation will shed more light on the utility of complement inhibition and facilitate precision medicine in ANCA vasculitis.

Effective management of necrotizing crescentic glomerulonephritis using an aggressive combination therapy including avacopan in a patient double-seropositive for anti-GBM antibodies and ANCA: a case report

The prognosis of anti-glomerular basement membrane (anti-GBM) nephritis, often accompanied by the presence of antineutrophil cytoplasmic antibodies (ANCA), is poor, and even with aggressive therapeutic approaches, kidney replacement therapy (KRT) is typically required. Here, we present a case of necrotizing crescentic glomerulonephritis in a patient double-seropositive for anti-GBM antibodies and ANCA who successfully achieved dialysis independence following aggressive treatment, including avacopan. The patient was a 77-year-old woman with rapidly progressive glomerulonephritis and double seropositivity for myeloperoxidase-ANCA and anti-GBM antibodies. A kidney biopsy revealed diffuse cellular crescents with necrosis and immunoglobin (Ig)G1 and IgG3 positivity on immunofluorescence staining, leading to a histological diagnosis of anti-glomerular basement membrane nephritis. Our treatment approach involved a novel combination of glucocorticoids, rituximab, low-dose cyclophosphamide, and plasma exchange complemented by avacopan. Temporary hemodialysis was required, and the patient successfully discontinued dialysis after 12 sessions despite a poor histological prognosis. This case underscores the significance of considering aggressive therapeutic strategies, including avacopan, for severe anti-GBM nephritis, even in the absence of lung involvement, to avert the need for KRT.

[Update on treatment of ANCA-associated vasculitis]

This article summarizes the current guidelines and recommendations published by the European Alliance of Associations for Rheumatology (EULAR), the Kidney Disease Improving Global Outcomes (KDIGO) and the American College of Rheumatology (ACR). In addition to glucocorticoids (GC), treatment with biologics is nowadays an established option to treat Anti-Neutrophil Cytoplasmic Antibody (ANCA)-associated vasculitis (AAV). Rituximab (RTX) is used for remission induction and maintenance in organ-threatening and non-organ-threatening granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA). For eosinophilic GPA (EGPA) anti-interleukin 5 (IL5) strategies are an important component of treatment for remission induction and maintenance of refractory or relapsing non-organ-threatening diseases in conjunction with GC. The dosing of GC for remission induction in GPA and MPA is now lower than was previously used and additionally, avacopan is approved as a new GC-sparing medication for GPA and MPA over 52 weeks. Conventional strategies, such as cyclophosphamide (CYC) are important for remission induction in severe or refractory organ-threatening disease for all AAVs. The use of methotrexate (MTX) and azathioprine (AZA) is becoming less prominent. The most important unanswered questions in the treatment of AAVs are with respect to the duration of remission maintenance treatment and the individualized treatment guidance based on biomarkers.

Early transition to avacopan from glucocorticoids applied during induction therapy for microscopic polyangiitis with rapidly progressive glomerulonephritis

Antineutrophil cytoplasmic antibody-associated vasculitis (AAV) is a systemic autoimmune disease characterized by necrotizing inflammation of small blood vessels. Glucocorticoids (GC) in combination with rituximab or cyclophosphamide can reduce AAV-related mortality and rescue renal function. However, several side effects associated with these agents, including GC toxicity, are concerning. Avacopan, an inhibitor of the C5a receptor, is now available for AAV treatment and is expected to mitigate GC toxicity. We present a case of myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA)-positive microscopic polyangiitis (MPA) with rapidly progressive glomerulonephritis treated with an early switch from GC to avacopan in combination with rituximab during induction therapy. Over a 6-month treatment period, clinical remission was achieved and maintained without infection or elevated liver enzyme levels. Efficacy and safety data regarding avacopan for AAV induction therapy remain limited. Therefore, more case reports are required to clarify the role of avacopan in AAV induction and maintenance therapy. Since the MPO-ANCA titer remained elevated despite the clinical remission of AAV in this case, the ANCA titer may not necessarily be a reliable biomarker for predicting AAV relapse when avacopan is applied as an induction therapy for AAV.

Superiority of Avacopan and Mepolizumab to Glucocorticoid Tapering in the Treatment of Anti-neutrophil Cytoplasmic Antibody (ANCA)-Associated Vasculitis: A Systematic Review

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) comprises a spectrum of autoimmune diseases, including granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). Studies have shown that avacopan and mepolizumab are promising therapeutics for partial or complete replacement of glucocorticoids (GC), with sustained remission while completely weaning off GC. Avacopan inhibits C5aR in the complement pathway, preventing neutrophil migration, while mepolizumab targets IL-5R, reducing eosinophil activity. Additionally, complement inhibition has not only contributed to the recovery of renal function and alleviation of physical symptoms but has also enhanced patients' overall quality of life and mental well-being. This systematic review explores the pathogenesis of AAV, traditional treatments, and the potential of emerging complement and interleukin antagonist therapies such as avacopan and mepolizumab in revolutionizing AAV management.

Treatment goals in ANCA-associated vasculitis: defining success in a new era

Health-related quality of life is a key contributor to overall well-being, and this is becoming an increasingly prominent factor when making therapeutic choices in the management of ANCA-associated vasculitis (AAV). Progress in available therapeutic strategies for AAV has resulted in this historically acute disease with a potentially fatal short-term outcome, becoming a relapsing-remitting chronic disorder. This new perspective on AAV means that patient survival should no longer be considered as the only major treatment target. Additional outcomes in this context that should be portrayed in order to consider a therapeutic approach as successful include patient quality of life, as well as the burden of treatment-induced morbidity. Comorbidities and impaired quality of life in patients with AAV, as with many other autoimmune diseases, may be a consequence of the disease itself as well as a result of the therapy employed. The AAV disease process may induce organ damage, including kidney failure and structural lung damage, and increase the risk of cardiovascular disease. On top of this, treatments employed to manage the disease may contribute further to the overall comorbidities burden. Furthermore, pre-existing comorbidities can increase AAV severity and may also be contraindications that limit potential therapeutic options. Quality of life is another central topic that can have a huge impact on patient wellbeing as well as adherence to treatment. Ongoing monitoring of comorbidity risk and of quality of life is thus key for successful AAV management. This process, however, may be complicated; the identification of the correct parameters on which to focus is not always straightforward and, more importantly, it is sometimes the symptoms that may appear trivial to physicians that are most detrimental to a patient's quality of life. With these shifts in treatment capabilities and understanding of patient burden, it is necessary to adjust the treatment paradigm accordingly. Treatment success is no longer defined solely by the control of disease activity; treatment success requires holistic improvement determined through the assessment of all aspects of the disease, ranging from disease control to comorbidity risk through to the assessment of health-related quality of life. This review explores the burden of AAV itself as well as treatment-related side effects with a special focus on the tools available to measure outcomes. The management of AAV has entered a new era with a strong focus on both the management and prevention of comorbidities as well as patient-reported outcomes, both of which are now considered key factors in defining treatment success.

Urinary complement biomarkers in immune-mediated kidney diseases

The complement system, an important part of the innate system, is known to play a central role in many immune mediated kidney diseases. All parts of the complement system including the classical, alternative, and mannose-binding lectin pathways have been implicated in complement-mediated kidney injury. Although complement components are thought to be mainly synthesized in the liver and activated in the circulation, emerging data suggest that complement is synthesized and activated inside the kidney leading to direct injury. Urinary complement biomarkers are likely a better reflection of inflammation within the kidneys as compared to traditional serum complement biomarkers which may be influenced by systemic inflammation. In addition, urinary complement biomarkers have the advantage of being non-invasive and easily accessible. With the rise of therapies targeting the complement pathways, there is a critical need to better understand the role of complement in kidney diseases and to develop reliable and non-invasive biomarkers to assess disease activity, predict treatment response and guide therapeutic interventions. In this review, we summarized the current knowledge on urinary complement biomarkers of kidney diseases due to immune complex deposition (lupus nephritis, primary membranous nephropathy, IgA nephropathy) and due to activation of the alternative pathway (C3 glomerulopathy, thrombotic microangiography, ANCA-associated vasculitis). We also address the limitations of current research and propose future directions for the discovery of urinary complement biomarkers.

Real-World Experience With Avacopan in Antineutrophil Cytoplasmic Autoantibody-Associated Vasculitis

Introduction

Postmarketing data on outcomes of avacopan use in antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) are lacking.

Methods

We performed a multicenter retrospective analysis of 92 patients with newly diagnosed or relapsing AAV who received therapy with avacopan. The coprimary outcome measures were clinical remission at 26 and 52 weeks. We use descriptive statistics and univariate logistic regression to assess outcomes and predictors of remission, respectively.

Results

Of the 92 patients, 23% (n = 21) had a baseline estimated glomerular filtration rate (eGFR) < 15 ml/min per 1.73 m2 and 10% on kidney replacement therapy at baseline. Among those with kidney involvement, mean (SD) enrollment eGFR was 33 (27) ml/min per 1.73 m2 with a mean (SD) change of +12 (25) and +20 (23) ml/min per 1.73 m2 at weeks 26 and 52, respectively. In addition to avacopan, 47% of patients received combination therapy of rituximab and low-dose cyclophosphamide, and 14% of patients received plasma exchange (PLEX). After induction, the median (interquartile range [IQR]) time to start avacopan was 3.6 (2.1-7.7) weeks, and the median time to discontinue prednisone after starting avacopan was 5.6 (3.3-9.5) weeks. Clinical remission was achieved in 90% of patients at week 26 and 84% of patients at week 52. Of the patients, 20% stopped avacopan due to adverse events, with the most common being elevated serum aminotransferases (4.3%).

Conclusion

A high rate of remission and an acceptable safety profile were observed with the use of avacopan in the treatment of AAV in this postmarketing analysis, including the populations excluded from the ADVOCATE trial.

ANCA-associated vasculitis-treatment standard

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) are characterized by small-vessel necrotizing inflammation, and prior to the advent of immunosuppressive therapy frequently had a fatal outcome. Treatment has transformed AAV into a relapsing/remitting disease with increased drug-related toxicities and organ damage. The use of glucocorticoids, cyclophosphamide and immunosuppressives (including azathioprine, mycophenolate and methotrexate) was optimized through a sequence of clinical trials establishing a standard of care against which subsequent targeted therapies could be developed. Improved understanding of pathophysiology has supported the development of B-cell depletion and complement inhibition in granulomatosis with polyangiitis and microscopic polyangiitis, and interleukin 5 inhibition for eosinophilic granulomatosis with polyangiitis, leading to the approval of newer agents for these conditions. There has been an increased attention on minimizing the adverse effects of treatment and on understanding the epidemiology of comorbidities in AAV. This review will focus on recent evidence from clinical trials, especially with respect to glucocorticoids, avacopan, plasma exchange, rituximab and mepolizumab, and their interpretation in the 2022 management recommendations by the European League of Associations of Rheumatology.

Antineutrophil cytoplasmic antibody-associated vasculitis

PURPOSE OF REVIEW

This review focuses on latest developments in managing antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV), a systemic autoimmune condition characterized by inflammation and necrosis of small blood vessels due to circulating autoantibodies that target neutrophilic granules.

RECENT FINDINGS

Our understanding of AAV pathogenesis has evolved in the past decades highlighting the central pathogenic roles of autoantibodies and complement activation. In parallel, the appreciation for glucocorticoid toxicity has led the research on crucial steroid-sparing therapeutic alternatives. Complement inhibitors (like avacopan) that have emerged are associated with better preservation of kidney function in AAV patients with severe kidney impairment. The role of plasma-exchange (PLEX) was revisited in updated guidelines that recommended its potential use in the context of diffuse alveolar hemorrhage associated hypoxia and severe kidney involvement, particularly with a serum creatinine level above 3.4 mg/dl. The ANCA Kidney Risk Score risk prediction and Glucocorticoid Toxicity Index score aid in identifying high-risk patients and individualizing management plans.

SUMMARY

Kidney involvement in AAV requires prompt diagnosis and initiation of immunosuppression to prevent irreversible nephron loss. Newer therapeutic targets are on the horizon and offer hope for personalized treatment strategies.

Application of biological agents in the treatment of anti-neutrophil cytoplasmic antibody-associated vasculitis

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) has been traditionally treated using glucocorticoids and immunosuppressants. However, these treatment modes are associated with high recurrence AAV rates and adverse reactions. Therefore, treatment strategies for AAV need to be urgently optimized. The efficacy and safety of biological agents in the treatment of vasculitis have been clinically validated. This review comprehensively summarizes the evidence-based support for the clinical use of existing biological agents in AAV. The findings reveal that multiple biological agents not only effectively reduce the adverse reactions associated with glucocorticoids and immunosuppressants but also demonstrate significant therapeutic efficacy. Notably, rituximab, an anti-CD20 antibody, has emerged as a first-line treatment option for AAV. Mepolizumab has shown promising results in relapsed and refractory eosinophilic granulomatosis with polyangiitis. Other biological agents targeting cytokines, complement, and other pathways have also demonstrated clinical benefits in recent studies. The widespread application of biological agents provides new insights into the treatment of AAV and is expected to drive further clinical research. These advancements not only improve patient outcomes but also offer more possibilities and hope in the field of AAV treatment.

Renal disease in pediatric rheumatology

PURPOSE OF REVIEW

This review will provide updates in the outcomes in the common rheumatologic diseases with kidney involvement. Covered are also advances in therapeutics for the use of pediatric rheumatologic diseases with kidney involvement, as well as the potential kidney complications from other rheumatologic diseases and their medications.

RECENT FINDINGS

Two of the more common rheumatologic diseases with kidney involvement, lupus and vasculitis, continue to show inadequate response to initial therapy of renal disease and practice continues to be driven by results of adult studies.

SUMMARY

There is a continued need for pediatric specific studies in rheumatologic diseases with kidney involvement as outcomes continue to be inadequate. Despite recently approved treatments for adults with rheumatic diseases and kidney involvement, therapeutic options in pediatrics remain limited, contributing to the overall morbidity and mortality.

Predictive Factors of Renal Recovery and Progression to End-Stage Kidney Disease in Patients With Antineutrophil Cytoplasmic Autoantibody-Associated Vasculitis With Severe Kidney Disease

Introduction

A significant number of patients with antineutrophil cytoplasmic antibodies (ANCA)- associated vasculitis (AAV) with glomerulonephritis (AAV-GN) still progress to end-stage kidney disease (ESKD, estimated glomerular filtration rate [eGFR] <15 ml/min per 1.73 m2) despite advances in remission-induction treatment.

Methods

This is a retrospective cohort study on myeloperoxidase (MPO)-ANCA or proteinase 3 (PR3)-ANCA positive patients with AAV (microscopic polyangiitis, MPA; or granulomatosis with polyangiitis, GPA) and eGFR <15 ml/min per 1.73 m2 or ESKD at presentation. Renal recovery, dialysis discontinuation, and persistence of ESKD after standard remission-induction, with or without the use of plasma exchange (PLEX) were analyzed.

Results

We analyzed 166 patients with biopsy-proven active AAV-GN and eGFR <15 ml/min per 1.73 m2 at the time of diagnosis. Patients received glucocorticoids with cyclophosphamide (CYC) (n = 84) or with rituximab (RTX) (n = 72) for remission-induction, and 49 received PLEX. The predictors of renal recovery were erythrocyte sedimentation rate, serum creatinine (SCr) at diagnosis, and minimal or mild chronicity changes. We further analyzed 71 patients who started dialysis with or without PLEX within 4 weeks of AAV-GN diagnosis. The predictors of dialysis discontinuation were minimal chronicity changes in kidney biopsy at diagnosis (odds ratio = 6.138; 95% confidence interval [CI]: 1.389-27.118; P = 0.017). Predictors of persistence of ESKD within 12 months included higher SCr at diagnosis (incidence rate ratio [IRR] = 1.086; 95% CI: 1.005-1.173; P = 0.037), and moderate (IRR = 3.797; 95% CI: 1.090-13.225; P = 0.036), or severe chronicity changes in kidney biopsy (IRR = 5.883; 95% CI: 1.542-22.439; P =0.009).

Conclusion

In our cohort, kidney recovery, dialysis discontinuation, and persistence of ESKD in patients with AAV-GN and eGFR <15 ml/min per 1.73 m2 depended on SCr and histologic findings on kidney biopsies at the time of diagnosis and was not affected by the addition of PLEX.

Executive summary of the KDIGO 2024 Clinical Practice Guideline for the Management of ANCA-Associated Vasculitis

In 2021, the Kidney Disease: Improving Global Outcomes (KDIGO) Guideline for the Management of Glomerular Diseases was published. KDIGO is committed to providing the nephrology community with periodic updates, based on new developments for each disease. For patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), avacopan received regulatory approval in late 2021, leading to this KDIGO guideline update. In addition, the evidence supporting a lower-dose glucocorticoid induction regimen or even complete replacement of glucocorticoids has become stronger. Herein, an executive summary of the most important guideline changes from the AAV chapter is provided as a quick reference.

Diagnosis and management of ANCA-associated vasculitis

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis consists of two main diseases, granulomatosis with polyangiitis and microscopic polyangiitis, and remains among the most devastating and potentially lethal forms of autoimmune inflammatory disease. Granulomatosis with polyangiitis and microscopic polyangiitis are characterised by a necrotising vasculitis that can involve almost any organ, and have generally been studied together. The diseases commonly affect the kidneys, lungs, upper respiratory tract, skin, eyes, and peripheral nerves. Granulomatous inflammation and multinucleated giant cells are key pathological hallmarks of granulomatosis with polyangiitis, but are absent in microscopic polyangiitis. Many immune system events are essential to disease aetiopathogenesis, such as activation of the alternative complement pathway, neutrophil activation via complement receptors, and the influx of inflammatory cells, including monocytes and macrophages. These cells perpetuate inflammation and lead to organ damage. During the 21st century, the management of ANCA-associated vasculitis has moved away from reliance on cytotoxic medications and towards targeted biological medications for both the induction and maintenance of disease remission. Earlier diagnosis, partly the result of more reliable ANCA testing, has led to improved patient outcomes and better survival. Reductions in acute disease-related mortality have now shifted focus to long-term morbidities related to ANCA-associated vasculitis and their treatments, such as chronic kidney disease and cardiovascular disease. Therapeutic approaches in both clinical trials and clinical practice still remain too reliant on glucocorticoids, and continued efforts to reduce toxicity from glucocorticoids remain a priority in the development of new treatment strategies.

Avacopan as an additional therapeutic intervention to promote renal recovery in severe ANCA-associated vasculitis: A case report

Avacopan, a C5a receptor antagonist (C5aR) presents a new therapeutic option to improve outcomes in ANCA-associated vasculitis (AAV). Here we present a case report of a patient initially requiring kidney replacement therapy (KRT), where avacopan was added as an additional adjunctive therapeutic agent late in the treatment course.

ANCA-Associated Vasculitis: Practical Issues in Management

ANCA associated vasculitides are multi-system autoimmune diseases which are increasing in prevalence. In this review we will discuss the clinical manifestations and review the management options. We highlight the various trials of induction and maintenance therapy and discuss the areas of unmet need. These include understanding which patients are at highest risk of relapse, clinical adaptation of improved biomarkers of disease activity and tools to discuss long term prognosis.

Management of antineutrophil cytoplasmic antibody-associated vasculitis with glomerulonephritis as proposed by the ACR 2021, EULAR 2022 and KDIGO 2021 guidelines/recommendations

Updated guidelines on the management of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) were released in 2021 by the American College of Rheumatology jointly with the Vasculitis Foundation and, subsequently, in 2022 by the European Alliance of Associations for Rheumatology. In addition, in 2021, the Kidney Disease: Improving Global Outcomes had released updated recommendations on the treatment of AAV with glomerulonephritis (AAV-GN). Kidney involvement is particularly relevant in microscopic polyangiitis and granulomatosis with polyangiitis, but is less frequent in eosinophilic granulomatosis with polyangiitis. The management of AAV-GN has been a focus for drug development and change over the past 10 years. Avoidance of progression to end-stage kidney disease (ESKD) or kidney failure is one of the main unmet needs in the management of AAV, with ESKD having a major impact on morbidity, health costs and mortality risk. Relevant changes in AAV-GN management are related to remission-induction treatment of patients with severe kidney disease, the use of glucocorticoids and avacopan, and remission-maintenance treatment. All the documents provide guidance in accordance with the evidence-based standard of care available at the time of their release. With our work we aim to (i) show the progress made and identify the differences between guidelines and recommendations, (ii) discuss the supporting rationale for those, and (iii) identify gaps in knowledge that could benefit from additional research and should be revised in subsequent updates.