A worldwide pharmacoepidemiological update of drug-associated ANCA-associated vasculitis at the time of targeted therapies

Kidney Failure in Pauci-immune Crescentic Glomerulonephritis: Rationale for Immunosuppression to Improve Kidney Outcome

PURPOSE OF REVIEW

Pauci-immune crescentic glomerulonephritis is the hallmark finding in ANCA-associated vasculitis (AAV) when the kidneys are affected. The rationale for immunosuppression in AAV is based on the underlying autoimmune nature of the disease. Overall remission rates, kidney outcomes, and the burden of disease have greatly improved since the discovery of various immunosuppressive therapies, but relapses remain common, and a significant proportion of patients continue to progress to end-stage kidney disease. Here, we review the role of immunosuppressive therapies for the treatment of pauci-immune crescentic glomerulonephritis.

RECENT FINDINGS

Besides the recognized role of B and T cells in the pathogenies of AAV, the focus on the contribution of inflammatory cytokines, neutrophil extracellular traps (NETs), and the complement system allowed the discovery of new therapies. Specifically, the C5a receptor blocker (avacopan) has been approved as a glucocorticoid-sparing agent. Additionally, based on observational data, more clinicians are now using combination therapies during the induction phase. There is also an evolving understanding of the role of plasma exchange in removing ANCA antibodies. Furthermore, the recent development of risk score systems provides physicians with valuable prognostic information that can influence decisions on immunosuppression, although future validation from larger cohorts is needed. The over-activation of various immune pathways plays a significant role in the pathogenesis of pauci-immune crescentic glomerulonephritis in AAV. Immunosuppression is, therefore, an important strategy to halt disease progression and improve overall outcomes. Relapse prevention while minimizing adverse events of immunosuppression is a major long-term goal in AAV management.

Comparison of agranulocytosis and anti-neutrophil cytoplasmic antibody-associated vasculitis caused by two antithyroid drugs: A pharmacovigilance study using the WHO international database

BACKGROUND

Methimazole (MMI) and propylthiouracil (PTU) are commonly used for patients with thyrotoxicosis. Agranulocytosis and antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is associated with high morbidity and mortality, requiring appropriate interventions. In this study, we compared adverse drug effects associated with MMI and PTU using a real-world large pharmacovigilance database.

METHODS

We searched all Individual Case Safety Reports reported to be associated with MMI and PTU, from VigiBase between 1967 and June 2, 2021. We conducted disproportionality analysis (case/non-case analysis) to analyze the difference in reported adverse drug reactions (ADRs) between antithyroid drugs (case) and the entire database (non-cases). We further analyzed information for the cases of agranulocytosis and AAV.

RESULTS

Among 11 632 cases of ADRs reported after MMI intake, agranulocytosis occurred in 1633 cases and AAV occurred in 41 cases. For 5055 cases of ADRs reported after PTU intake, agranulocytosis occurred in 459 cases and AAV occurred in 110 cases. Agranulocytosis occurred after a median of 28 days after PTU intake and 33 days after MMI intake. More than 95% of the agranulocytosis cases were classified as serious, but most of them (65.1% for PTU and 70.4% for MMI) were reported to have recovered after dechallenge actions; mostly drug withdrawal. AAV occurred after a median of 668 days after PTU intake, and 1162 days after MMI intake.

CONCLUSIONS

This is a pharmacoepidemiological study investigating agranulocytosis and AAV caused by MMI and PTU. Through this research, we could provide more specific insights into a safe prescription of antithyroid drugs in a real-world setting.

Presentation and progression of MPO-ANCA interstitial lung disease

The association between MPO-ANCA-associated vasculitis (AAV) and interstitial lung disease (ILD) has been well established. Pulmonary fibrosis may coexist with, follow, or even precede the diagnosis of AAV, and its presence adversely affects the prognosis. The optimal approach to investigating ANCA in patients with ILD remains a subject of ongoing debate. Here we aim to describe presentation and progression of MPO-ANCA ILD. We conducted a retrospective evaluation of a cohort of individuals diagnosed with MPO-ANCA ILD, with or without accompanying renal impairment, at the Immunology and Cell Therapy Unit, Careggi University Hospital, Florence, Italy, between June 2016 and June 2022. Clinical records, imaging studies, pathologic examinations, and laboratory test results were collected. Among the 14 patients identified with MPO-ANCA ILD, we observed a significant association between MPO-ANCA titers assessed at the time of ILD diagnosis and renal involvement. Renal impairment in these cases often manifested as subclinical or slowly progressive kidney damage. Interestingly, complement C3 deposits were consistently found in all renal biopsy specimens, thereby suggesting the potential for novel therapeutic targets in managing renal complications associated with MPO-ANCA ILD. The presentation of MPO-ANCA vasculitis as ILD can be the first and only clinical manifestation. MPO-ANCA levels at ILD diagnosis could warn on the progression to renal involvement in patients with MPO-ANCA ILD, hence caution is needed because renal disease can be subclinical or smoldering.

ANCA-Associated Vasculitis

ANCA-associated vasculitis (AAV) is a necrotizing, small-to-medium vessel vasculitis associated with significant morbidity and mortality. AAV is a systemic autoimmune disease affecting kidneys, eyes, sinuses, peripheral nerves, skin, and upper and lower respiratory tracts. AAV tends to present in characteristic phenotypes categorized clinically as granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic GPA (EGPA). Kidney involvement is a common feature of AAV, and has important implications on disease prognosis and management. Existing therapies have been refined and improvements in our understanding of the pathophysiology of AAV has led to approval of novel therapies. In this review, we provide an overview of epidemiology, disease mechanisms, clinical presentation and review therapeutic strategies for induction and maintenance of remission.

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.

Focal Alveolar Hemorrhage Secondary to Hydralazine-Associated Antineutrophilic Cytoplasmic Antibody Vasculitis

Hydralazine is rarely associated with antineutrophilic cytoplasmic antibody (ANCA) vasculitis. In the appropriate clinical scenario, such as in a patient with pulmonary, renal, or cutaneous manifestations, finding antibodies against nuclear and cytoplasmic neutrophil antigens may suggest drug-induced vasculitis after exposure to hydralazine. We present the case of an elderly man diagnosed with focal alveolar hemorrhage with elevated concentrations of anti-myeloperoxidase antibody, anti-proteinase-3 antibody, and antinuclear antibodies in the setting of prolonged hydralazine therapy. We observed a rapid clinical improvement with hydralazine discontinuation and systemic corticosteroids. We did not observe further disease activity while on mycophenolate mofetil six months later.

Classification and epidemiology of vasculitis: Emerging concepts

The recent publication of the American College of Rheumatology (ACR)-European Alliance of Associations for Rheumatology (EULAR) classification criteria for large vessel vasculitis and anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAVs) has provided modern criteria for the classification of these conditions, which incorporate contemporary methods of investigation and diagnosis. Further validation is required in independent cohorts, especially from populations that were not well represented in the development cohort. Studies of the occurrence of large vessel vasculitis report that Takayasu arteritis is a rare disease in most populations, and giant cell arteritis is the most common vasculitis in older populations. The incidence of AAV appears to have plateaued, but the prevalence is increasing as a result of lower mortality. The new classification criteria may affect the reported incidence and prevalence, and studies will be needed to confirm this. The impact of COVID-19 on the occurrence of the vasculitides is not completely known, but there is evidence of reduced occurrence of Kawasaki disease and IgA-associated vasculitis following lockdowns with reduced transmission of possible trigger infectious agents.

Hypertrophic Pachymeningitis Associated with Myeloperoxidase-anti-neutrophil Cytoplasmic Antibodies Induced by Propylthiouracil: A Case Report

A 71-year-old man with hyperthyroidism complained of headache lasting two months. He had been using propylthiouracil (PTU) for 14 years. Treatment intensification did not improve the symptoms. Blood tests detected a positive myeloperoxidase-anti-neutrophil cytoplasmic antibody (MPO-ANCA). Diffuse dural thickening was identified by magnetic resonance imaging. The patient was diagnosed with hypertrophic pachymeningitis (HP) due to ANCA-associated vasculitis (AAV). He received methylprednisolone pulse therapy followed by prednisolone and methotrexate, which improved his headache. PTU-induced AAV-related HP is a rare and indiscernible disease. Therefore, the possibility of the disease should be proactively considered when a PTU user experiences refractory headaches.

Antineutrophil Cytoplasmic Antibody-associated Vasculitis after COVID-19 Vaccination with Pfizer-BioNTech

The extent of rare side effects of mRNA vaccines for coronavirus disease 2019 (COVID-19) remains unclear. Several cases of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) following COVID-19 vaccination have been reported. We herein report a 72-year-old man who presented with a fever after receiving the second dose of the Pfizer-BioNTech COVID-19 vaccine. He was diagnosed with acute kidney injury due to myeloperoxidase-ANCA-associated vasculitis and was treated with intermittent hemodialysis, high-dose prednisolone, and intravenous rituximab. His general symptoms and renal impairment subsequently improved. When systemic symptoms are prolonged or renal abnormalities appear after COVID-19 vaccination, the possibility of AAV should be considered.

Rituximab Induction and Maintenance in ANCA-Associated Vasculitis: State of the Art and Future Perspectives

Antineutrophil cytoplasmatic antibody (ANCA)-associated vasculitis (AAV) is a group of rare autoimmune diseases characterized by inflammation of the vascular wall. The pathogenesis of AAV is strongly associated with B cell-derived ANCAs; thus, Rituximab (RTX) has become a promising drug in the induction and maintenance treatment of AAV. The purpose of this review is to describe the efficacy and safety of RTX in the induction of remission and maintenance therapy of AAV. Herein, we summarize the randomized controlled trials that have contributed to the refinement of the use of RTX in AAV in the past decades. RTX has been proven to be effective both in new-onset disease and in relapsing disease. Although the optimal duration of AAV maintenance therapy remains unknown, the ANCAs and the B-cell repopulation may offer support for the administration of further RTX cycles (or not). The safety of RTX is comparable with cyclophosphamide, with the advantage of a low risk of malignancy and no concern for fertility. In conclusion, RTX now plays an important role in the induction and maintenance therapy of AAV. Optimizing RTX-based treatment strategies in AAV is one of the main goals of the current research in AAV.