From the FDA Drug Label
Following 2 years of treatment with RITUXAN + MTX, 57% of patients had no progression of structural damage. A total of 197 patients with active, severe GPA and MPA (two forms of ANCA Associated Vasculitides) were treated in a randomized, double-blind, active-controlled, multicenter, non-inferiority study, conducted in two phases – a 6 month remission induction phase and a 12 month remission maintenance phase. The main outcome measure for both GPA and MPA patients was achievement of complete remission at 6 months defined as a BVAS/GPA of 0, and off glucocorticoid therapy The study demonstrated non-inferiority of RITUXAN to cyclophosphamide for complete remission at 6 months
The diagnosis and treatment approach for a patient suspected of having ANCA-associated vasculitis involves:
- Induction treatment: RITUXAN 375 mg/m2 once weekly for 4 weeks or oral cyclophosphamide 2 mg/kg daily for 3 to 6 months
- Remission maintenance: Azathioprine for patients who received cyclophosphamide, while RITUXAN group did not receive additional therapy to maintain remission
- Complete remission: Defined as a BVAS/GPA of 0, and off glucocorticoid therapy, with 64% of patients achieving complete remission at 6 months in the RITUXAN group
- Retreatment of flares: Based on investigator judgment, with 15 patients receiving a second course of RITUXAN therapy for treatment of relapse of disease activity 1
From the Research
ANCA-associated vasculitis diagnosis and treatment should prioritize a combination of clinical evaluation, laboratory testing, and tissue biopsy, with rituximab being a preferable option for both induction and maintenance of remission, as supported by the most recent evidence 2.
Diagnostic Approach
The diagnostic approach for ANCA-associated vasculitis includes:
- Testing for ANCA antibodies (specifically PR3-ANCA and MPO-ANCA) using high-quality immunoassays as the primary screening method, as recommended by the 2017 international consensus on ANCA testing 3
- Complete blood count
- Inflammatory markers
- Kidney function tests
- Urinalysis
- Often a biopsy of affected tissue
Treatment Approach
Treatment typically follows a two-phase approach:
- Induction of remission: rituximab (375 mg/m² weekly for 4 weeks) is a preferable option, alongside high-dose corticosteroids (typically prednisone 1 mg/kg/day, maximum 60-80 mg daily) 2
- Maintenance therapy: less toxic medications like azathioprine (2 mg/kg/day), methotrexate (20-25 mg weekly), or mycophenolate mofetil (2 g/day) are used with tapering corticosteroids
- Treatment duration typically involves 3-6 months of induction therapy followed by at least 18-24 months of maintenance therapy
- Plasma exchange may be considered in cases with severe kidney involvement or pulmonary hemorrhage, although recent data does not support its routine use 2
- Regular monitoring of disease activity, medication side effects, and organ function is essential throughout treatment
Key Considerations
- The distinction between PR3-ANCAs and MPO-ANCAs has important clinical and pathogenic implications 3
- ANCA testing should be done in the right clinical context, as positive results can occur in other conditions than vasculitis 4
- New methodologies, such as automated reading in the IIF test and third-generation assays, are available for ANCA testing, but their diagnostic value is still under discussion 4