Rituximab for IgA Vasculitis: Limited Evidence but Promising for Refractory Cases
Rituximab is not a standard first-line therapy for IgA vasculitis (Henoch-Schönlein purpura), but appears to be an effective and safe option for adult patients with refractory or relapsing disease, particularly those with severe renal involvement who have failed conventional immunosuppression. 1, 2
Critical Distinction: IgA Vasculitis vs ANCA-Associated Vasculitis
The provided guidelines address ANCA-associated vasculitis (AAV), which includes granulomatosis with polyangiitis and microscopic polyangiitis—these are distinct entities from IgA vasculitis 3. The KDIGO 2024 and EULAR/ERA-EDTA guidelines do not provide recommendations for IgA vasculitis treatment 3.
Evidence for Rituximab in IgA Vasculitis
Efficacy Data
A systematic review of 35 IgA vasculitis patients treated with rituximab demonstrated 94.3% clinical improvement and 74.3% sustained remission at final follow-up 1
In a multicenter cohort of 22 adult-onset IgA vasculitis patients, 90.9% achieved remission with rituximab, with significant reductions in proteinuria (P < 0.0001), inflammatory markers, and prednisone requirements 2
Among patients who relapsed after initial rituximab response (31.4%), retreatment with rituximab achieved good disease control in all cases 1
Patient Selection Criteria
Rituximab should be considered for:
Refractory or relapsing disease despite glucocorticoids and conventional immunosuppressants (85.7% of treated patients in systematic review) 1
Severe renal involvement with progressive impairment—nearly 90% of rituximab-treated patients had renal involvement 1
Contraindications to conventional immunosuppression (8.6% of cases) 1
Adult patients preferentially, as most published data involves adult-onset disease 2
Dosing Protocols
While no standardized protocol exists for IgA vasculitis specifically, the published literature utilized:
375 mg/m² weekly for 4 consecutive weeks (standard lymphoma protocol), or 4, 5
1000 mg on days 1 and 15 (rheumatoid arthritis protocol) 2
Rituximab was administered as add-on therapy in 73% of cases and as monotherapy in 27% 2
Safety Profile
Rituximab was generally well tolerated with only 8.6% experiencing minor adverse effects in the systematic review 1
One death occurred after 60 months of follow-up in the multicenter cohort, though causality was unclear 2
No new safety signals were identified beyond the known rituximab safety profile 1, 2
Clinical Response Timeline
Dissociated response patterns have been observed:
Constitutional and vasculitic symptoms typically improve within days to weeks 4
Granulomatous manifestations regress more slowly over several months 4
Renal parameters (proteinuria, GFR) show progressive improvement over the treatment course 2
Relapse Management
Relapse rates of 35-37% have been reported after initial rituximab-induced remission 6, 1
Retreatment with rituximab is effective, achieving disease control in all retreated patients 1
Fixed-interval rituximab re-treatment (1 gm every 6 months for 2 years) reduced relapse rates to 12% during the re-treatment period in AAV patients, though this protocol has not been formally studied in IgA vasculitis 6
Important Caveats
All published evidence consists of case reports, case series, and observational studies—no randomized controlled trials exist for rituximab in IgA vasculitis 1, 2
The mechanism of action in IgA vasculitis (IgA1-dominant immune complex disease) differs from ANCA-associated vasculitis (pauci-immune), so extrapolation from AAV guidelines is inappropriate 2
Controlled clinical trials are still warranted to definitively establish rituximab's role in IgA vasculitis 1
Pediatric data is limited, though some pediatric cases were included in the systematic review 1