Accurately measuring medication exposure over time is essential for clinical research, adverse-event monitoring, and treatment optimization. However, this is difficult when utilizing electronic health record (EHR) data, especially when prescriptions include variable dosing instructions or frequent dose changes [1]. Glucocorticoid (GC) use in inflammatory disease exemplifies this challenge. GCs are typically initiated at higher doses with a gradual taper and may be altered based on disease response [2, 3]. Additionally, cumulative exposure is clinically important because of its association with substantial metabolic and infectious side effects. [4, 5] While natural language processing (NLP) approaches have been used to extract medication information, many existing methods focus on identifying medications or extracting single-dose information rather than reconstructing dose changes over time [6, 7]. This study aimed to develop and validate a large language model (LLM)–assisted NLP pipeline for extracting GC tapering instructions from semi-structured EHR prescription data and calculating longitudinal Patients with International Classification of Diseases, Ninth or Tenth Revision diagnosis codes for giant cell arteritis and/or polymyalgia rheumatica were included if GC prescriptions covered at least 75% of days within a 12-month follow-up period. Prescription data were preprocessed using BigQuery SQL. Gemini-2.5-Flash was prompted using a few-shot strategy to extract tapering instructions, and a Python-based deterministic parsing module converted model outputs into structured daily dose values. The pipeline calculated 365-day cumulative GC exposure, which was compared with manually reviewed reference doses. Performance was evaluated using correlation, classification metrics, Cohen κ, and absolute percentage error.cumulative GC exposure. Patients with International Classification of Diseases, Ninth or Tenth Revision diagnosis codes for giant cell arteritis and/or polymyalgia rheumatica were included if GC prescriptions covered at least 75% of days within a 12-month follow-up period. Prescription data were preprocessed using BigQuery SQL. Gemini-2.5-Flash was prompted using a few-shot strategy to extract tapering instructions, and a Python-based deterministic parsing module converted model outputs into structured daily dose values. The pipeline calculated 365-day cumulative GC exposure, which was compared with manually reviewed reference doses. Performance was evaluated using correlation, classification metrics, Cohen κ, and absolute percentage error. After filtering adequate prescription coverage, 100 patients were included in the final analysis. Pipeline-derived cumulative 365-day doses correlated strongly with manually reviewed reference doses (r=0.84; P<.001). When cumulative doses were categorized into low-, medium-, and high-dose groups, the model achieved 80% accuracy, 85% precision, 73% recall, an F1 score of 76%, and an area under the receiver operating characteristic curve of 94% for identifying the highest-risk dose category. The mean individual-level absolute percentage error was 23%, while cohort-level error was 7%. In prescription-level validation, 100 records were annotated for accuracy in dose extraction. The model achieved an accuracy of 96%, a macro F1 score of 97%, and a quadratic-weighted Cohen Kappa of 94% (un-weighted: 93%). An LLM–assisted NLP pipeline combined with deterministic parsing can extract complex GC tapering instructions from semi-structured EHR prescription data and estimate longitudinal cumulative medication exposure. This approach offers a scalable solution for medication exposure assessment in clinical research cohorts, particularly when manual review is not feasible. Further validation is needed across other medication classes, clinical settings, and EHR systems. N/A

OBJECTIVE:The objective of the study was to determine risk factors for relapse of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) after reinduction of remission with rituximab and discontinuation of maintenance therapy. METHODS:This is a post hoc analysis of the RITAZAREM clinical trial. Patients aged 15 years or older with AAV and a positive test for anti-proteinase-3 or anti-myeloperoxidase-ANCA who achieved remission after reinduction with rituximab and glucocorticoids were randomized at month 4 to receive continued rituximab or azathioprine for a maintenance period up to 24 months, followed by observation until relapse or up to 48 months. Generalized estimating equations logistic regression identified baseline and time-varying risk factors for relapse by the next visit for the two study phases: maintenance (months 4-24) and off-treatment (months 24-48). RESULTS:Among 170 patients (median [interquartile range] age 59 [48-68] years, disease duration 5 [2-10] years), 99 relapses occurred (46 during maintenance). During maintenance, musculoskeletal involvement (odds ratio [OR]: 2.8, 95% confidence interval [CI]: 1.1-7.2; P = 0.03) and higher patient global assessment (OR: 1.1, 95% CI: 1.0-1.2; P = 0.04) were associated with relapse. During the off-treatment phase, presence of CD19+ B cells (OR: 2.5, 95% CI: 1.2-5.1; P = 0.01) and reappearance of ANCA (OR: 3.2, 95% CI: 1.3-7.7; P = 0.01) were each associated with higher relapse risk. Multivariable analysis identified markers of inflammation (changes in platelets, white blood cells, and IgA) associated with relapse. CONCLUSION:Risk factors for relapse in AAV vary by treatment phase. Monitoring markers of inflammation and immune reconstitution may identify patients at risk for relapse, particularly after treatment withdrawal.

OBJECTIVE:Diffuse alveolar hemorrhage (DAH) is a life-threatening presentation of antineutrophil cytoplasmic antibody-associated vasculitis (AAV). Patients with AAV are at an increased risk of venous thromboembolic events (VTEs). These manifestations can co-occur; however, the prognosis and management of these patients are poorly understood. METHODS:In this retrospective observational study, we included patients diagnosed with AAV who presented with both DAH and VTE during the same outpatient visit or in the same inpatient treatment episode. RESULTS:Among 121 patients with proven DAH secondary to AAV managed at our institution, 14 (11.6%) were also diagnosed with VTE. Patients were predominantly men (71%) with median age at diagnosis of 67 (interquartile range 56-72) years. Five patients were diagnosed with DAH followed by VTE, four patients were diagnosed with VTE before developing DAH (T-AAV), and five patients were diagnosed with VTE and DAH simultaneously (HT-AAV). Inferior vena cava filters were placed in 13 patients (93%). Although most patients received systemic anticoagulation within 30 days of DAH diagnosis, anticoagulation management was individualized based on clinical presentation. One patient with preexisting interstitial lung disease died of respiratory failure after initially presenting with pulmonary embolism and later developing DAH during hospitalization. Bleeding complications, including recurrent DAH or retroperitoneal hematoma, were observed in six patients (43%). Three patients (21%) experienced progression or recurrence of VTE within 90 days. CONCLUSION:Management of patients with DAH and VTE is challenging and should be guided by the severity of DAH, additional organ manifestations of AAV, and risk stratification of the presenting VTE.

BackgroundRituximab is effective for induction and maintenance of remission in relapsing ANCA-associated vasculitis (AAV), but some patients do not achieve complete remission or experience relapse despite treatment. We aimed to describe the frequency, characteristics, and outcomes of patients with suboptimal response to rituximab within the RITAZAREM trial.MethodsPost hoc descriptive analysis, including patients with granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA) treated with rituximab for induction (N = 188) and those receiving rituximab maintenance (N = 85). Three scenarios of suboptimal response were examined: (i) failure to achieve protocol-defined remission at month 4 (n = 6); (ii) incomplete remission at month 4, defined as BVAS/WG = 1 (n = 10); and (iii) relapse during rituximab maintenance (n = 13). Data were summarized descriptively. Time to relapse from month 4 in patients with BVAS/WG = 1 versus BVAS/WG = 0 was explored using Kaplan–Meier analysis.ResultsSix of 188 patients (3%) did not achieve protocol-defined remission by month 4, 10 (5%) had residual low-grade disease activity (BVAS/WG = 1), and 13 of 85 patients (15%) receiving rituximab maintenance relapsed within 24 months during maintenance treatment. All patients with BVAS/WG = 1 at month 4 had a history of PR3-ANCA positivity and ear/nose/throat (ENT) baseline manifestations. Relapse occurred more frequently in this subgroup than in patients with BVAS/WG = 0, and time-to-relapse analysis showed shorter relapse-free survival, although interpretation is limited by the small sample size. Most first relapses were minor, and some patients subsequently experienced additional relapses, including major relapses.ConclusionIn this exploratory and hypothesis-generating analysis, a small subset of patients with relapsing AAV showed suboptimal outcomes with rituximab. Residual disease activity at month 4, particularly in patients with PR3-ANCA positivity and ENT involvement, may represent a clinical subgroup associated with an increased frequency of earlier relapse, although this observation requires confirmation.

Eosinophilic granulomatosis with polyangiitis (EGPA) is a small-vessel vasculitis associated with anti-neutrophil cytoplasmic antibodies and characterized by blood and tissue eosinophilia, severe respiratory manifestations, and multiorgan involvement. The management of newly diagnosed EGPA still relies on therapeutic strategies that were initially validated for other forms of anti-neutrophil cytoplasmic antibody-associated vasculitis, including microscopic polyangiitis and granulomatosis with polyangiitis. Whereas the long-term prognosis of microscopic polyangiitis and granulomatosis with polyangiitis depends primarily on controlling initial organ involvement and preventing relapses, EGPA is distinguished by chronic involvement of both upper and lower respiratory airways, which often necessitates prolonged glucocorticoid therapy. Data from clinical trials suggest that targeting the IL-5 pathway with mepolizumab or benralizumab can effectively control persistent respiratory symptoms and reduce the need for glucocorticoids, yet the role of these agents in the management of EGPA at the time of diagnosis and in the long term remains to be defined. Emerging retrospective data on therapies targeting other type 2 cytokines (such as IL-4, IL-13 and thymic stromal lymphopoietin) suggest potential benefits for relapsing respiratory symptoms; however, prospective evidence remains limited and safety has yet to be established. This Review discusses the role of these new targeted therapies in the management of EGPA, alongside historical treatments.

INTRODUCTION:ANCA-associated vasculitis (AAV) can have several pulmonary manifestations. There is limited knowledge of the epidemiology and complications of pulmonary manifestations in AAV, despite their association with increased mortality and reduced health-related quality of life. METHODS:This study retrospectively analyzed a large, multicentre longitudinal cohort of individuals with AAV followed between 2006 and 2023. Data included diagnosis, demographics, comorbidities, time of disease onset, and pulmonary manifestations of disease. Measures of both disease activity and damage were recorded. Results were summarized across disease sub-types and manifestations. RESULTS:Data from 1026 individuals were analyzed, including 860 with granulomatosis with polyangiitis (GPA) and 166 with microscopic polyangiitis (MPA). Pulmonary manifestations were seen at any time in the disease course within 81.3% of individuals: 711 (82.7%) with GPA and 123 (74.1%) with MPA. Pulmonary manifestations were reported in 644 (62.7%) at disease onset and 456 (44.4%) individuals during follow-up. Nodules and cavities, diffuse alveolar hemorrhage, and inflammatory infiltrates were the three most common manifestations across the cohort. Nodules and cavities were the most frequent manifestation seen in GPA and diffuse alveolar hemorrhage in MPA. Multiple pulmonary manifestations were seen within 51.9% of individuals with pulmonary manifestations. Pulmonary manifestations were seen in 41.4% of episodes of relapse. 17.4% of those with pulmonary manifestations sustained pulmonary damage from their disease. CONCLUSION:Pulmonary manifestations are common in AAV and are associated with permanent damage. Systematic assessments of individuals with AAV for pulmonary involvement will likely improve detection of these manifestations.

Introduction Avacopan has demonstrated efficacy as a glucocorticoid-sparing therapy in ANCA-associated vasculitis (AAV), but its benefit in patients with severe renal involvement treated with rituximab remains uncertain. Methods We conducted a retrospective comparative cohort study at Mayo Clinic including patients with AAV and eGFR <30 mL/min/1.73 m2 at induction treated with rituximab plus avacopan (n=30) or rituximab alone (n=120) between 2010 and 2025. Co-primary outcomes were time to renal remission (no >25% eGFR decline and hematuria ≤10 RBC/HPF), analyzed by Kaplan-Meier and Cox proportional hazards regression, and longitudinal eGFR trajectory, analyzed by linear mixed-effects models. Results Baseline characteristics were well balanced. Median eGFR was 15.0 and 16.0 mL/min/1.73 m2 and dialysis was required at baseline in 13.3% and 12.5% in the avacopan and rituximab groups, respectively. Avacopan significantly reduced cumulative prednisone exposure at 12 months (1.8 vs 4.3 g; p<0.001) and shortened time to prednisone discontinuation (3.3 vs 7.3 months; log-rank p<0.001). On adjusted Cox regression, renal remission did not differ significantly between groups (HR 0.74, 95% CI 0.45–1.21; p=0.232). Longitudinal eGFR trajectories did not differ significantly between groups. One patient (3.3%) discontinued avacopan due to drug-induced liver injury, with transaminase normalization following discontinuation. Conclusion In our cohort of patients with AAV and severe renal involvement treated with rituximab-based induction, avacopan did not improve renal remission rates or longitudinal eGFR trajectory in comparison to glucocorticoids but achieved significant and faster glucocorticoid reduction with an acceptable safety profile.

Rationale: The 1-year double-blind period of the MANDARA trial (NCT04157348) demonstrated non-inferiority of benralizumab to mepolizumab for achieving remission, in adults with relapsing/refractory eosinophilic granulomatosis with polyangiitis (EGPA). Here, we report the 2-year combined double-blind and ongoing open-label extension (OLE) data. Methods: On completion of the double-blind period (n=136/140) comparing benralizumab 1x30mg versus mepolizumab 3x100mg subcutaneously every 4 weeks, patients were invited to enter the OLE where they continued benralizumab (benra/benra) or switched from mepolizumab to benralizumab (mepo/benra). Endpoints included remission (Birmingham Vasculitis Activity Score=0 and oral glucocorticoid [OGC[ dose ≤4 mg/day), OGC use, relapse, blood eosinophil count (bEOS), Asthma Control Questionnaire (ACQ-6), pre-bronchodilator forced expiratory volume in 1 second (pre-BD FEV1), and safety. Results: In total, 128 patients entered the OLE (n=66 benra/benra, n=62 mepo/benra; mean age 52.8 years; 60.2% female), and 119 completed OLE Year 1. Baseline characteristics of those entering the OLE were similar to the double-blind period. At Week 104, over 60% in both groups (41 [62.1%] benra/benra and 42 [67.7%] mepo/benra patients) achieved remission. During the OLE, 51 (77.3%) benra/benra and 42 (67.7%) mepo/benra patients had no relapses. The percentage of benra/benra patients who discontinued OGCs was similar at Weeks 49-52 (27 [40.9%]) and Weeks 101-104 (29 [43.9%]), while the percentage increased for mepo/benra patients between Weeks 49-52 (16 [25.8%]) and Weeks 101-104 (27 [43.5%]; Figure). The median (IQR) OGC dose at Weeks 101-104 was 0.5 (0,5) in benra/benra and 1.36 (0,5) mg/day in mepo/benra patients. The median (IQR) bEOS in benra/benra patients was 20 (10,40) cells/µL at both Weeks 52 and 100; bEOS were depleted in mepo/benra patients from 70 (40,90) cells/µL to 20 (10,50) cells/µL by 4 weeks after switching. Mean (SD) ACQ-6 scores were 0.64 (0.78) in benra/benra patients and 0.60 (0.76) in mepo/benra patients at Week 104 compared with 1.39 (1.18) and 1.11 (0.95) at baseline. Mean (SD) pre-BD FEV1 was 2.59 (0.90) L versus 2.62 (0.84) L in benra/benra versus mepo/benra patients at Week 52, and 2.61 (0.90) versus 2.63 (0.81) L, at Week 100. Safety of mepolizumab and benralizumab was consistent with their known profiles. Conclusions: In patients with EGPA receiving benralizumab, remission rates, OGC discontinuation, and bEOS depletion were durable over 104 weeks with low relapse rates, and without loss of asthma control or lung function decline. Additional bEOS depletion and OGC sparing was observed in patients switching from mepolizumab to benralizumab.

ObjectiveThe ADVOCATE trial demonstrated that treatment of active granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA) with avacopan was noninferior in achieving remission at week 26 and superior for sustained remission at week 52 compared with a prednisone taper. This analysis of ADVOCATE evaluated the efficacy and safety of avacopan in patients with ear, nose, throat (ENT), or lung manifestations.MethodsThis post hoc analysis included patients enrolled in ADVOCATE with ENT or lung manifestations at baseline. Outcomes included remission at weeks 26 and 52, respiratory tract manifestations over time, relapse rate, glucocorticoid‐related toxicity, health‐related quality of life (HRQoL), and safety.ResultsADVOCATE included 144 patients with ENT manifestations (avacopan: n = 75, prednisone taper: n = 69) and 142 with lung manifestations (avacopan: n = 71, prednisone taper: n = 71). Among patients with ENT manifestations, remission was achieved at week 26 by 72.0% (avacopan group) and 71.0% (prednisone taper group) and was sustained at week 52 by 62.7% (avacopan) and 53.6% (prednisone taper). Among patients with lung manifestations, remission was achieved at week 26 by 73.2% (avacopan) and 66.2% (prednisone taper) and sustained at week 52 by 67.6% (avacopan) and 53.5% (prednisone taper). The relapse rate, glucocorticoid toxicity, and measures of HRQoL favored avacopan for both respiratory tract manifestation groups. Safety was comparable across treatment groups.ConclusionPatients with GPA or MPA with ENT or lung manifestations demonstrated similar responses to avacopan, reflecting results reported in the overall ADVOCATE trial population and supporting the administration of avacopan in these subgroups.

OBJECTIVES:To summarise the efficacy and safety of 2 years of anti-interleukin-5/receptor (anti-IL-5/R) therapy in patients with eosinophilic granulomatosis with polyangiitis (EGPA). METHODS:Patients were randomised 1:1 to receive benralizumab or mepolizumab every 4 weeks during the 52-week double-blind period of the MANDARA trial. Patients entered an open-label extension (OLE) in which they continued benralizumab (benralizumab/benralizumab) or switched from mepolizumab to benralizumab (mepolizumab/benralizumab). Remission (Birmingham Vasculitis Activity Score = 0 and oral glucocorticoid [OGC] dose ≤4 mg/d), OGC use, relapse, blood eosinophil count (bEOS), and safety up to year 2 (week 104) were reported. RESULTS:A total of 128 patients entered the OLE period (n = 66 benralizumab/benralizumab; n = 62 mepolizumab/benralizumab). At week 104, 41 (62.1%) benralizumab/benralizumab patients and 42 (67.7%) mepolizumab/benralizumab patients were in remission. During OLE year 1, 51 (77.3%) benralizumab/benralizumab patients and 42 (67.7%) mepolizumab/benralizumab patients had no relapses. By weeks 49 to 52, 27 (40.9%) benralizumab/benralizumab patients and 16 (25.8%) mepolizumab/benralizumab patients had withdrawn from OGCs, increasing to 29 (43.9%) and 27 (43.5%) at weeks 101 to 104, respectively; the median cumulative OGC dose was 950 mg and 791 mg during OLE year 1, respectively. The median bEOS among benralizumab/benralizumab-treated patients was 20 cells/µL (at weeks 52 and 100), and in mepolizumab/benralizumab-treated patients, it decreased from 70 cells/µL to 20 cells/µL 4 weeks after switching. Adverse events/serious adverse events were reported in 97.0%/22.7% of benralizumab/benralizumab and 100%/35.5% of mepolizumab/benralizumab patients. CONCLUSIONS:In patients with EGPA, treatment for 2 years with anti-IL-5/R therapies is associated with durable rates of remission, discontinuation of OGCs, bEOS depletion, and low relapse rates. Switching from mepolizumab to benralizumab enhances bEOS depletion and OGC sparing.

To determine risk factors for relapse of ANCA‐associated vasculitis (AAV) after re‐induction of remission with rituximab and discontinuation of maintenance therapy. This is a post‐hoc analysis of the RITAZAREM clinical trial. Patients 15 years or older with AAV and a positive test for anti‐proteinase‐3 (PR3‐) or anti‐myeloperoxidase (MPO)‐ANCA who achieved remission after re‐induction with rituximab and glucocorticoids were randomized at month 4 to receive continued rituximab or azathioprine for a maintenance period up to 24 months, followed by observation until relapse or up to 48 months. Generalized estimating equations logistic regression identified baseline and time‐varying risk factors for relapse by the next visit for the two study phases: maintenance (months 4‐24) and off‐treatment (months 24‐48). Among 170 patients (median (IQR) age 59 (48‐68) years, disease duration 5 (2‐10) years), 99 relapses occurred (46 during maintenance). During maintenance, musculoskeletal involvement (odds ratio (OR) [95% confidence interval (CI)]: 2.8 [1.1, 7.2], p=0.03) and higher patient global assessment (OR [95% CI]: 1.1 [1.0, 1.2], p=0.04) were associated with relapse. During the off‐treatment phase, presence of CD19+ B‐cells (OR [95% CI]: 2.5 [1.2, 5.1], p=0.01) and reappearance of ANCA (OR [95% CI]: 3.2 [1.3, 7.7], p=0.01) were each associated with higher relapse risk. Multivariable analysis identified markers of inflammation (changes in platelets, white blood cells, and immunoglobulin A) associated with relapse. Risk factors for relapse in AAV vary by treatment phase. Monitoring markers of inflammation and immune reconstitution may identify patients at risk for relapse, particularly after treatment withdrawal.

Objectives Eosinophilic granulomatosis with polyangiitis (EGPA) is a complex, multisystem form of vasculitis. MANDARA (NCT04157348) was a phase 3 clinical trial comparing the efficacy and safety of benralizumab versus mepolizumab, in addition to standard of care, for relapsing/refractory EGPA. This qualitative interview substudy explored study participants’ experiences with EGPA and their participation in the trial. Methods Thirty-eight patients from 5 countries participating in MANDARA opted into a longitudinal qualitative substudy, which comprised two 60-minute, semistructured, one-to-one telephone interviews conducted by trained interviewers between December 2019 and June 2023. Topics discussed included motivation to join the trial, time since diagnosis, symptoms, and impacts of EGPA and their degree of ‘bothersomeness’ and ‘disturbance’. Results The desire to stop or reduce the use of oral glucocorticoids was the most frequently mentioned motivation for, and expectation of, participation in the trial. Comparison of interviews between the 2 time points suggested patients experienced reductions in the number and impact of EGPA-related symptoms and bothersomeness and/or disturbance ratings. Most improved symptoms included difficulty breathing, nasal congestion/discharge, and fatigue, and most improved impacts included ability to exercise, quality/quantity of sleep, and ability to engage in social activities. Conclusions This study provides insights regarding patients’ perspectives of EGPA and their perceptions and experiences associated with receiving an anti-interleukin-5/receptor therapy. These findings highlight the need for effective treatments that allow patients to reduce their use of oral glucocorticoids and the importance of assessing patient experiences when gauging treatment efficacy in EGPA.

This mini review explores the association of interstitial lung disease (ILD) with antineutrophil cystoplasmic antibodies (ANCA) and the clinical syndrome of microscopic polyangiitis (MPA). Reports on radiographic and histopathologic findings as well as genetic predispositions are reviewed. Based on this evidence a concept for the pathogenesis of the relationship of ILD, MPO-ANCA and MPA is proposed. Finally, a practical clinical management approach to patients presenting either with ILD and a positive ANCA test result, or to patients with MPA found to have pulmonary abnormalities qualifying as an ILD, is derived from the currently available literature. Treatment of these patients is based on up-to-date guidelines for the management of ILD as well as ANCA-associated vasculitis.

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) encompasses three rare yet interrelated diseases: granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA) and eosinophilic granulomatosis with polyangiitis (EGPA). Despite increasing recognition, the diagnosis of AAV remains challenging, even in specialized medical centres, owing to its clinical heterogeneity, overlap with mimicking conditions, and the variable performance of ANCA testing. The assessment of a patient suspected of AAV requires a timely synthesis of symptoms, physical examination, laboratory tests, histopathology and imaging data to substantiate the diagnosis, exclude alternative diagnoses, assess disease activity and extent, and enable rapid initiation of appropriate therapies. Classification is similarly complex, and evolving classification systems are based on clinical phenotype, ANCA specificity or a combination of both, each with implications for disease monitoring, therapeutic decisions and trial design. Assessing disease severity and predicting prognosis are fundamental but complicated by the diverse patterns of organ involvement, relapsing–remitting course and co-morbidities. Although validated tools exist for measuring disease activity, organ damage and prognosis, many limitations remain, particularly in identifying smouldering disease, irreversible damage and risk of relapse. Emerging therapies have improved outcomes, with recovery of kidney function, better overall survival and improved glucocorticoid-related toxicity, but patients with AAV continue to experience high risks of chronic morbidity and early mortality. This Review explores current challenges and opportunities in the diagnosis, classification and prognostic assessment of AAV, and outlines a structured framework to support personalized and outcome-focused care. ANCA-associated vasculitis (AAV) includes three disease subtypes with partly overlapping clinical manifestations: granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA) and eosinophilic granulomatosis with polyangiitis (EGPA). This Review article provides an update on the diagnosis and classification of AAV, discussing parameters for assessing disease activity and predicting outcomes towards a personalized medicine approach.