Induction Therapy for Pediatric ANCA Vasculitis

Disease Classification and Treatment Approach

The American College of Rheumatology recommends that ANCA-associated vasculitis should be categorized according to severity to guide appropriate treatment decisions: localized, early systemic, generalized, severe, or refractory 1
Treatment intensity should be tailored based on disease severity, with more aggressive therapy for organ or life-threatening manifestations, as suggested by the European League Against Rheumatism 1, 2

The Kidney International guideline recommends cyclophosphamide can be administered as: oral, 2 mg/kg/day for 3 months (maximum 6 months) 3
The Kidney International guideline also recommends cyclophosphamide can be administered as: intravenous, 15 mg/kg at weeks 0, 2, 4, 7, 10, 13 (and weeks 16, 19, 21, 24 if required) 3, 4
Dose adjustments are necessary for reduced renal function (reduce by 0.5 mg/kg/day for oral or 2.5 mg/kg for IV if GFR <30 ml/min/1.73 m²), according to the Kidney International guideline 3
The Annals of the Rheumatic Diseases recommends MESNA should be administered with cyclophosphamide to prevent hemorrhagic cystitis 2
The Kidney International guideline recommends rituximab dosing: 375 mg/m² weekly for 4 weeks 3
The Kidney International guideline suggests rituximab can be combined with limited cyclophosphamide (15 mg/kg at weeks 0 and 2) for severe disease 3
The Arthritis and Rheumatology guideline suggests recent evidence shows reduced-dose glucocorticoid regimens (0.5 mg/kg/day) may be as effective as high-dose regimens (1 mg/kg/day) with fewer adverse effects 5
A structured tapering schedule should be followed as outlined in the PEXIVAS trial, according to the Kidney International guideline 4

For patients with severe disease (creatinine >5.6 mg/dl or other vital organ failure), the Kidney International guideline recommends considering plasma exchange for patients with serum creatinine >3.4 mg/dl (>300 mmol/l), requiring dialysis, rapidly increasing creatinine, or diffuse alveolar hemorrhage with hypoxemia 3, 4
The Kidney International guideline suggests more intensive immunosuppression with combination therapy (rituximab plus limited cyclophosphamide) may be beneficial for severe disease 3

The Annals of the Rheumatic Diseases recommends all patients receiving cyclophosphamide should receive Pneumocystis jirovecii pneumonia prophylaxis with trimethoprim/sulfamethoxazole (800/160 mg on alternate days or 400/80 mg daily) 1, 6
Regular monitoring of blood counts, renal function, and urinalysis is essential, as suggested by the Praxis Medical Insights guideline 7

The Kidney International guideline recommends avacopan (C5a receptor antagonist) may be considered as an alternative to glucocorticoids in combination with rituximab or cyclophosphamide, particularly in patients at high risk for glucocorticoid toxicity 3, 4
The Kidney International guideline suggests mycophenolate mofetil (2000 mg/day in divided doses) may be considered for non-severe disease, particularly in MPO-ANCA positive patients 3, 8

The Kidney International guideline recommends after achieving remission, transition to maintenance therapy with either rituximab (using scheduled dosing protocols) or azathioprine (1.5-2 mg/kg/day) 3, 7
Maintenance therapy should typically be continued for 18 months to 4 years after induction of remission, according to the Kidney International guideline 3

The American College of Nephrology recommends mycophenolate mofetil (MMF) as an alternative agent for non-severe ANCA-associated vasculitis in pediatric patients, particularly for those with MPO-ANCA positivity, or as a maintenance therapy option after remission is achieved with first-line agents 9, 10

MMF is positioned as an alternative agent rather than first-line therapy for induction treatment in pediatric ANCA-associated vasculitis, according to the European Renal Association 9, 10
For induction therapy in non-organ-threatening or non-life-threatening disease, MMF can be considered as an alternative to rituximab, as suggested by the European League Against Rheumatism 11
MMF is recommended as an alternative to azathioprine for maintenance therapy in patients who are intolerant to azathioprine, based on guidelines from the National Kidney Foundation 9

Standard MMF dosing for maintenance therapy in ANCA vasculitis is 2000 mg/day in divided doses, as recommended by the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines 9, 12
Treatment duration for maintenance therapy with MMF is typically 2 years after achieving complete remission, according to the American Society of Nephrology 9

MMF has demonstrated similar remission rates to cyclophosphamide for patients with both PR3-ANCA and MPO-ANCA in non-life-threatening disease, as reported by the American College of Rheumatology 10
However, patients with PR3-ANCA positivity treated with MMF have shown a significantly increased relapse risk compared to those treated with cyclophosphamide, according to the European Renal Association 10
MMF appears more effective in MPO-ANCA positive patients, making it a more suitable option for this subgroup, as suggested by the National Institute of Arthritis and Musculoskeletal and Skin Diseases 10

MMF generally has a more favorable toxicity profile compared to cyclophosphamide, particularly regarding fertility preservation, which is an important consideration in pediatric patients, as noted by the American Academy of Pediatrics 13

For non-severe disease, consider MMF as an alternative, especially in MPO-ANCA positive patients, as recommended by the European League Against Rheumatism 10
Consider MMF for patients with concerns about fertility preservation, based on guidelines from the American Society for Reproductive Medicine 13
Avoid MMF in patients with PR3-ANCA positivity due to higher relapse rates, as suggested by the National Kidney Foundation 10

The optimal duration of MMF therapy in pediatric patients is not definitively established, according to the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines 9