INTRODUCTION

MAIN SUBJECTS
Important considerations when selecting therapeutic agents for AAV
1) Assessment of disease stages
Table 1
2) Defining disease activity status
Table 2
Available guidelines for management of AAV
Table 3
Pharmacologic agents | BSR and BHPR guideline [15] | EULAR/ERA-EDTA recommendations [18] | 2021 ACR/Vasculitis Foundation Guideline [21] | KDIGO 2021 Clinical Practice Guideline [27] |
---|---|---|---|---|
RTX | ||||
Remission induction |
- Effective as CYC in previously untreated patients and CYC intolerance - Preferred when CYC avoidance is desired (infertility, risk of infection) |
- New-onset organ- or life-threatening AAV |
- Conditionally recommended over CYC in active, severe GPA/MPA - May be prescribed in active, severe EGPA - Conditionally recommended over MEP in active, severe EGPA |
- Initial treatment for new-onset AAV - Combination of RTX/CYC can be considered when creatinine >354 μmol/L |
Maintenance | - May be considered | - Maintenance |
- Conditionally recommended over MTX or AZA after achieving remission with CYC or RTX in severe GPA/MPA - Scheduled re-dosing conditionally recommended over using ANCA titer or CD19+ B cells based approach |
- Preferred option in relapsing and PR3-ANCA positive disease, frail elderly, for glucocorticoid sparing, AZA allergy - Either on a fixed schedule or following reappearance of CD19+ B cells and/or ANCA |
Relapsing disease | - In the case of major relapse | - In the case of major relapse |
- Conditionally recommended over CYC in severe GPA/MPA relapse not receiving RTX maintenance - RTX conditionally recommended over CYC in severe EGPA relapse previously reached remission with CYC or RTX |
- Preferred than CYC in life- or organ- threatening relapse |
Refractory disease | - More effective than CYC, and initial choice when previously RTX untreated | - CYC refractory | - Switching to RTX conditionally recommended over RTX/CYC combination in CYC refractory severe GPA/MPA | - If CYC used previously |
CYC | ||||
Remission induction | - Remission induction | - New-onset organ- or life-threatening AAV |
- May be used in RTX avoidance or active disease with RTX treatment in active, severe GPA/MPA - May be prescribed in active, severe EGPA - Conditionally recommended over MEP in active, severe EGPA |
- Initial treatment for new-onset AAV - Preferred in severe renal impairment (creatinine >354 μmol/l) - Combination of two pulses of IV RTX/CYC can be considered when creatinine >354 μmol/l |
Relapsing disease | - In the case of major relapse | - In the case of major relapse | - Conditionally recommended over additional RTX in severe GPA/MPA relapse while receiving RTX maintenance | - In life- or organ- threatening relapse setting |
Refractory disease | - If RTX refractory | - Switching to CYC conditionally recommended over RTX/CYC combination in RTX refractory severe GPA/MPA | - If RTX used previously | |
GC | ||||
Remission induction |
- Combination with CYC or RTX - High dosage (1 mg/kg, up to 60 mg), usually in PO prednisolone, IV can be used |
- Combination with CYC or RTX in new-onset organ- or life-threatening AAV - Combination with MTX or MMF in non-organ-threatening AAV |
- Reduced dose GC conditionally recommended over a standard doseGC regimen in active, severe GPA/MPA - Initial therapy of active, severe EGPA |
- Combination with CYC or RTX - No evidence for IV GC administration |
Maintenance | - Maintenance | - Low dose GC with AZA, RTX, MTX, or MMF | - Maintenance |
- Following CYC induction, rapid dose reduction into 5 mg/day by 6 months - May be withdrawn following RTX induction - Continue 5~7.5 mg/day for 2 years and slowly reduced by 1 mg every 2 months |
Relapsing disease | - Dose adjustment (IV may be considered in major relapse) |
- Combination with CYC or RTX - In the case of major relapse |
- Relapsing disease | - Dose adjustment (PO or IV) |
Refractory disease | - Dose adjustment (PO or IV) |
AAV: antineutrophil cytoplasmic antibody-associated vasculitis, ACR: American College of Rheumatology, ANCA: antineutrophil cytoplasmic antibody, AZA: azathioprine, BHPR: British Health Professionals in Rheumatology, BSR: British Society for Rheumatology, CYC: cyclophosphamide, EGPA: eosinophilic granulomatosis with polyangiitis, ERAEDTA: European Renal Association-European Dialysis and Transplant Association, EULAR: European League Against Rheumatism, GC: glucocorticoid GPA: granulomatosis with polyangiitis, IV: intravenous, KDIGO: Kidney Disease: Improving Global Outcome, MEP: mepolizumab, MMF: mycophenolate mofetil, MPA: microscopic polyangiitis, MTX: methotrexate, PO: per oral, PR3: proteinase 3, RTX: rituximab.
Table 4
Pharmacologic agents | BSR and BHPR guideline [15] | EULAR/ERA-EDTA recommendations [18] | 2021 ACR/Vasculitis Foundation Guideline [21] | KDIGO 2021 Clinical Practice Guideline [27] |
---|---|---|---|---|
MTX | ||||
Remission induction | - Evidence of low disease activity and not at risk of organ damage by the BVAS |
- Non-organ-threatening AAV (nasal and paranasal disease without erosion, cartilage collapse, olfactory dysfunction, deafness, skin involvement without ulcer, myositis, non-cavitating pulmonary nodule/infiltrate in the absence of haemoptysis) with normal kidney function - Not for meningeal involvement, retro-orbital disease, cardiac and mesenteric involvement, acute mononeuritis multiplex, pulmonary haemorrhage |
- MTX conditionally recommended over CYC or RTX for active, non-severe GPA - GC+MTX conditionally recommended over GC alone in active, non-severe GPA - GC+MTX conditionally recommended over GC+AZA or GC+MMF in active, non-severe GPA - GC+MTX conditionally recommended over GC+TMP/SMX in active, non-severe GPA - GC+MTX conditionally recommended over GC alone in active, non-severe EGPA |
- In the absence of irreversible tissue damage |
Maintenance | - Maintenance | - Maintenance |
- Conditionally recommended over MMF/LEF after achieving remission with CYC or RTX in severe GPA/MPA - Conditionally recommended over TMP/SMX in GPA entering remission - GC+MTX conditionally recommended over GC alone or GC+CYC or RTX in active, non-severe EGPA - Conditionally recommended over RTX in severe EGPA entering remission with CYC - Conditionally recommended over MEP in severe EGPA that entered remission |
- Upon MTX based remission induction - Intolerant to AZA and MMF - Not if GFR <60 mL/min/1.73 m2 |
AZA | ||||
Remission induction | - GC+AZA conditionally recommended over GC alone or GC+CYC or RTX in active, non-severe EGPA | |||
Maintenance | - Maintenance | - Maintenance |
- Conditionally recommended over MMF/LEF after achieving remission with CYC or RTX in severe GPA/MPA - Conditionally recommended over TMP/SMX in GPA entering remission - Conditionally recommended over RTX in severe EGPA entering remission with CYC - Conditionally recommended over MEP in severe EGPA that entered remission |
- Preferred in baseline IgG <300 mg/dL, HBsAg positive, and limited access to RTX |
MMF | ||||
Remission induction | - May be an alternative to MTX |
- Non-organ-threatening AAV - Not for meningeal involvement, retro-orbital disease, cardiac and mesenteric involvement, acute mononeuritis multiplex, pulmonary haemorrhage |
- GC+MMF conditionally recommended over GC alone or GC+CYC or RTX in active, non-severe EGPA | - Remission induction |
Maintenance | - Alternative for intolerance or lack of efficacy to AZA or MTX | - Maintenance |
- Intolerable or contraindications to MTX, AZA, or RTX - Conditionally recommended over RTX in severe EGPA entering remission with CYC - Conditionally recommended over MEP in severe EGPA that entered remission |
- Maintenance |
Relapse | - Non-severe relapse |
AAV: antineutrophil cytoplasmic antibody-associated vasculitis, ACR: American College of Rheumatology, AZA: azathioprine, BHPR: British Health Professionals in Rheumatology, BSR: British Society for Rheumatology, BVAS: Birmingham Vasculitis Activity Score, CYC: cyclophosphamide, EGPA: eosinophilic granulomatosis with polyangiitis, ERA-EDTA: European Renal Association-European Dialysis and Transplant Association, EULAR: European League Against Rheumatism, GC: glucocorticoid, GFR: glomerular filtration rate, GPA: granulomatosis with polyangiitis, KDIGO: Kidney Disease: Improving Global Outcome, LEF: leflunomide, MEP: mepolizumab, MMF: mycophenolate mofetil, MTX: methotrexate, RTX: rituximab, TMP/SMX: trimethoprim/sulfamethoxazole.
Table 5
Therapeutic options | BSR and BHPR guideline [15] | EULAR/ERA-EDTA recommendations [18] | 2021 ACR/Vasculitis Foundation Guideline [21] | KDIGO 2021 Clinical Practice Guideline [27] |
---|---|---|---|---|
LEF | ||||
Maintenance | - Alternative for intolerance or lack of efficacy to AZA or MTX | - When intolerance to AZA, MTX, MMF, or RTX present | ||
MEP | ||||
Remission induction | - GC+MEP conditionally recommended over MTX, AZA, or MMF combined GC in active, non-severe EGPA | |||
Relapsing disease |
- Adding MEP conditionally recommended over switching to other agent in non-severe EGPA relapse under MTX, AZA, or MMF therapy - Adding MEP conditionally recommended over adding MTX, AZA, or MMF in non-severe EGPA relapse under low-dose GC monotherapy - Conditionally recommended over omalizumab in non-severe EGPA relapse under MTX, AZA, or MMF in those with high serum IgE levels |
|||
PLEX | ||||
Remission induction |
- Adjunct with GC+CYC in severe renal failure (creatinine >500 μmol/L) - Considered in the presence of life-threatening manifestation (i.e., pulmonary hemorrhage) |
- Considered in patients with creatinine >500 μmol/L due to rapidly progressive glomerulonephritis - Considered in severe diffuse alveolar haemorrhage |
- Routine addition conditionally recommended against in GPA/MPA with active glomerulonephritis - Advisable in GPA/MPA having anti-GBM disease - Conditionally recommend against adding PLEX in active, severe GPA/MPA with alveolar hemorrhage |
- In combination with induction regimen ● Patients with creatinine >500 μmol/L requiring dialysis ● Patients with diffuse alveolar hemorrhage with hypoxemia ● Overlap of AAV and anti-GBM antibody |
Relapsing disease | - Addition may be considered in the case of major relapse with GC+RTX or CYC |
- Considered in patients with creatinine >500 μmol/L due to rapidly progressive glomerulonephritis - Considered in severe diffuse alveolar haemorrhage |
- Can be considered | |
Refractory disease | - Can be considered |
AAV: antineutrophil cytoplasmic antibody-associated vasculitis, ACR: American College of Rheumatology, AZA: azathioprine, BHPR: British Health Professionals in Rheumatology, BSR: British Society for Rheumatology, CYC: cyclophosphamide, EGPA: eosinophilic granulomatosis with polyangiitis, ERA-EDTA: European Renal Association-European Dialysis and Transplant Association, EULAR: European League Against Rheumatism, GBM: glomerular basement membrane, GC: glucocorticoid, GPA: granulomatosis with polyangiitis, IgE: immunoglobulin E, KDIGO: Kidney Disease: Improving Global Outcome, LEF: leflunomide, MEP: mepolizumab, MMF: mycophenolate mofetil, MPA: microscopic polyangiitis, MTX: methotrexate, PLEX: plasma exchange, RTX: rituximab.
Table 6
BSR and BHPR guideline [15] |
EULAR/ERA-EDTA recommendations [18] |
2021 ACR/Vasculitis Foundation Guideline [21] |
KDIGO 2021 Clinical Practice Guideline [27] |
|
---|---|---|---|---|
RTX |
- 375 mg/m2/week for 4 weeks; 1 g at week 0 and 2 shows equal efficacy - 1 g every 4~6 months as maintenance therapy for two years, either as a fixed-interval regimen or evidence of relapse |
- 375 mg/m2/week for 4 weeks or 1 g at week 0 and 2 in adults - 575 mg/m2 for patients with body surface area ≤1.5 m2 or 750 mg/m2 for patients with body surface area >1.5 m2 (maximum of 1 gm/infusion, at week 0 and 2) in children - 1 g every 4~6 months as maintenance therapy for two years, either as a fixed-interval regimen or evidence of relapse |
- Remission induction ● 375 mg/m2/week for 4 weeks or 1 g at week 0 and 2 ● CYC/RTX combination: RTX 375 mg/m2/week for 4 weeks with IV CYC 15 mg/kg at week 0 and 2 or RTX 1 g at week 0 and 2 with CYC 500 mg/biweekly ×6 - Maintenance ● 500 mg twice on complete remission and 500 mg at month 6, 12, and 18 or 1 g after remission induction, followed by infusion at month 4, 8, 12, and 16 - Special consideration ● Limited data for severe renal impairment remission induction (creatinine >354 μmol/L) ● Preferred in young aged and frail elderly patients, considering fertility issues, glucocorticoid sparing, relapsing, and PR3-ANCA positivity |
|
CYC |
- IV preferred owing to low toxicity, 2-week interval and in a 3-week interval subsequently following the CYCLOPS trial regimen - 15 mg/kg standard dosage, reduced in the elderly and decreased renal function - Administered for 3~6 months - Lifelong exposure should be ≤25 g - Monitoring of leukopenia/cytopenia |
- Dose of up to PO 2 mg/kg/day for 3~6 months or IV 15 mg/kg every 2 week for 3 dosage, followed by every 3 weeks for at least 3 doses |
- Remission induction ● PO 2 mg/kg/day for 3 months to a maximum of 6 months (dose reduction by age 60 and 70, and GFR <30 mL/min/1.73 m2) ● IV 15 mg/kg at week 0, 2, 4, 7, 10, 13 (extended until 16, 19, 21, 24, if necessary; dose adjustment according to age 60 and 70, GFR <30 mL/min/1.73 m2) ● CYC/RTX combination: RTX 375 mg/m2/week for 4 weeks with IV CYC 15 mg/kg at week 0 and 2 or RTX 1 g at week 0 and 2 with CYC 500 mg/biweekly ×6 |
|
GC |
- Either PO or IV - Longer use may increase infection, but with fewer relapses - Rapid dose reduction to 15 mg prednisolone at week 12 on remission induction - Consider GC tapering when sustained remission for at least 1 year on maintenance therapy |
- Rapid dose reduction to 7.5~10 mg prednisolone (or equivalent) at week 12 |
- Either PO or IV - IV pulse GC: Methylprednisolone 500-100 mg/day or 30 mg/kg/day for adults and children or equivalent for 3~5 days - High-dose oral GC: Prednisone 1 mg/kg/day in adults and 1~2 mg/kg/day for children (up to 80 mg in adults and 60 mg in children) or equivalent |
- 1 mg/kg/day at week 1, and sequential tapering |
PLEX |
- In severe kidney disease: 7 treatments in a maximum of 14 days, with volume and albumin replacement - In diffuse pulmonary hemorrhage: Daily until hemorrhage cessation, with fresh frozen plasma - Anti-GBM antibody positive: Daily for 14 days or anti-GBM antibody negative conversion |
|||
MTX |
- Dose of up to 25~30 mg/week - Prohibited in moderate-severe renal impairment |
- Dose of up to 25 mg/week (SC or PO) - Should be administered in caution or avoided in those with moderate-several renal impairment |
||
AZA | - Maintenance | - Maintenance | - Dose of up to 2 mg/kg/day |
- 1.5~2 mg/kg/day at complete remission until one year, decrease by 25 mg every 3 months - Continuation until four years after complete remission: dose of 1.5~2 mg/kg/day for 18~24 month, 1 mg/kg/day until 4 years, and taper by 25 mg every 3 month |
MMF | - Dose up to 3 g/day | - Dose of up to 3 g/day |
- Remission induction ● 2 g/day, dose of up to 3 g/day in poor response - Maintenance ● 2 g/day for 2 years at complete remission |
|
LEF | ||||
MEP | - SC every 4 weeks |
ACR: American College of Rheumatology, ANCA: antineutrophil cytoplasmic antibody, AZA: azathioprine, BHPR: British Health Professionals in Rheumatology, BSR: British Society for Rheumatology, CYC: cyclophosphamide, ERA-EDTA: European Renal Association-European Dialysis and Transplant Association, EULAR: European League Against Rheumatism, GBM: glomerular basement membrane, GC: glucocorticoid, GFR: glomerular filtration rate, IV: intravenous, KDIGO: Kidney Disease: Improving Global Outcome, LEF: leflunomide, MEP: mepolizumab, MMF: mycophenolate mofetil, MTX: methotrexate, PLEX: plasma exchange, PO: per oral, PR3: proteinase 3, RTX: rituximab, SC: subcutaneous.
Table 7
Other treatment considerations | BSR and BHPR guideline [15] |
EULAR/ERA-EDTA recommendations [18] |
2021 ACR/Vasculitis Foundation Guideline [21] |
KDIGO 2021 Clinical Practice Guideline [27] |
---|---|---|---|---|
Maintenance duration |
- At least 24 months following remission - Up to 5 years in patients with GPA or PR3-ANCA serology positive |
- At least 24 months after sustained remission induction - 36 months therapy in PR3-ANCA positive patients |
- Guided by disease and patient factors |
- Between 18 months and 4 years after induction with AZA+GC - Unknown in RTX, evaluated up to 18 months |
Treatment withdrawal | - Immunosuppressive agent withdrawal after GC withdrawal | - Treatment discontinuation after 3 months in dialysis and in the absence of extrarenal manifestation | ||
Disease status assessment | - Using BVAS, VDI, SF-36, ANCA testing | |||
Treatment adverse effect monitoring/adjunct measures |
- Investigation of drivers in refractory disease - Blood test and urinalysis monitoring - Mesna for protection against CYC toxicity and CYC-related infertility consultation - Immunoglobulin testing prior to each RTX cycle - Antifungal prophylaxis and TMP/SMX for Pneumocystis jiroveci prophylaxis - Nasal mupirocin for Staphylococcal aureus treatment - Cervical intraepithelial neoplasia screening for females - Osteoporosis prophylaxis - Tuberculosis screening - Pnuemococcal, influenza, and hepatitis B vaccination - Assessment of cardiovascular and thromboembolic risk |
- Structured clinical assessment for clinical decisions rather than ANCA testing - Utilizing clinical tools for systematic clinical assessment - Perform regular blood test and urinalysis - Hematuria work up in patients treated with CYC and administration of anti-emetics and mesna upon IV CYC treatment - Serum immunoglobulin testing prior to each cycle of RTX and those with recurrent infection, as well as when considering the use of IV immunoglobulin - Cardiovascular risk regular monitoring - Comorbidity assessment - TMP/SMX prophylaxis for CYC treated patients - Topical mupirocin may be considered in chronic carriage of Staphylococcal aureus nasal disease - Re-evaluation of the specific cause in refractory disease - Recommend active immunization against infections (herpes zoster, pneumococcus and influenza), while avoiding live attenuated vaccines |
- TMP/SMX for Pneumocystis jiroveci prophylaxis conditionally recommended when receiving RTX or CYC, and in moderate-dose GC using and immunosuppressive agent combination setting - Adding TMP/SMX to other therapies for GPA maintenance conditionally recommended against - Immunoglobulin supplementation in IgG <3 gm/L and recurrent severe infection under RTX maintenance - GC toxicity monitoring - Addition of IV immunoglobulin conditionally recommended in remission induction refractory GPA/MPA or active GPA/MPA that is unable to receive other immunomodulatory therapy - Nasal rinses and topical nasal therapies may be beneficial in sinonasal GPA and EGPA - Reconstructive surgery conditionally recommended in GPA under remission upon patient desire - Immunosuppression conditionally recommended over surgical dilation in actively inflamed subglottic and/or endobronchial tissue with stenosis or surgical removal in the presence of mass lesions - Dosing immunosuppression conditionally recommended against based on merely ANCA titer results - Consider renal transplantation in GPA/MPA with stage 5 CKD in remission - Echocardiogram evaluation at disease diagnosis and Five-Factor Score guided therapy conditionally recommended in EGPA - Continuation of leukotriene inhibitor conditionally recommended over discontinuation in newly diagnosed EGPA |
- No changes in treatment decision based on ANCA serology changes solely - Potential of an oral C5a receptor antagonist, avacopan, for reducing GC exposure - TMP/SMX advised for Pneumocystis jiroveci prophylaxis during CYC or RTX treatment, longer-term use in those with structural lung disease, ongoing immunosuppressive or GC therapy - Use of validated scoring system, such as BVAS to evaluate clinically active disease - Structured assessment in parallel with laboratory testing - Transplantation consideration after complete clinical remission of ≥6 months - Cause evaluation for refractory disease |
ACR: American College of Rheumatology, ANCA: antineutrophil cytoplasmic antibody, AZA: azathioprine, BHPR: British Health Professionals in Rheumatology, BSR: British Society for Rheumatology, BVAS: Birmingham Vasculitis Activity Score, CKD: chronic kidney disease, CYC: cyclophosphamide, EGPA: eosinophilic granulomatosis with polyangiitis, ERA-EDTA: European Renal Association-European Dialysis and Transplant Association, EULAR: European League Against Rheumatism, GC: glucocorticoid, GPA: granulomatosis with polyangiitis, IV: intravenous, KDIGO: Kidney Disease: Improving Global Outcome, MPA: microscopic polyangiitis, PR3: proteinase 3, RTX: rituximab, SF-36: short form-36, TMP/SMX: trimethoprim/sulfamethoxazole, VDI: Vasculitis Damage Index.
1) BSR and BHPR guideline for management of adults with AAV
2) EULAR/ERA-EDTA recommendation for management of AAV
3) 2021 ACR/Vasculitis Foundation Guideline for the Management of AAV
4) KDIGO 2021 Clinical Practice Guideline for the Management of Glomerular Diseases
5) 2022 Update of the EULAR Recommendations on the Management of AAV
Table 8
AAV: antineutrophil cytoplasmic antibody-associated vasculitis, ANCA: antineutrophil cytoplasmic antibody, AZA: azathioprine, CYC: cyclophosphamide, EGPA: eosinophilic granulomatosis with polyangiitis, ERA-EDTA: European Renal Association-European Dialysis and Transplant Association, EULAR: European League Against Rheumatism, GC: glucococticoid, GPA: granulomatosis with polyangiitis, MEP: mepolizumab, MMF: mycophenolate mofetil, MPA: microscopic polyangiitis, MPO: myeloperoxidase, MTX: methotrexate, PLEX: plasma exchange, PR3: proteinase 3, RTX: rituximab, TMP/SMX: trimethoprim/sulfamethoxazole.
6) Novel therapeutic agents for AAV

CONCLUSION
