Background
Phase 3, multicenter, double-blind, placebo-controlled RCT (RAIHA study). 32 adults with newly diagnosed warm AIHA who had received corticosteroids for less than 6 weeks. All patients received prednisone 1 mg/kg/day for 2 weeks then tapered per predefined scheme. Enrolled at French national referral centers for adult immune cytopenias. This is the only double-blind placebo-controlled RCT of rituximab in first-line warm AIHA.
Interventions and follow up
Arm A: Rituximab 1000 mg IV × 2 infusions (2 weeks apart) + prednisone
Arm B: Placebo infusion × 2 + prednisone
Primary endpoint: Overall response rate (CR + PR) at 1 year by intent-to-treat analysi
mFollow up: 2 year
Arm B: Placebo infusion × 2 + prednisone
Primary endpoint: Overall response rate (CR + PR) at 1 year by intent-to-treat analysi
mFollow up: 2 year
Results
ORR at 1 year (ITT): 75% (11 CR + 1 PR) vs 31% (5 CR), P=.032
CR at 2 years: 10/16 (rituximab) vs 3/16 (placebo), P=.011
Mortality at 2 years: 0 deaths (rituximab) vs 6 deaths (placebo), P=.017
Severe infections: 2 (rituximab) vs 6 (placebo), P=.39 — not significant
CR at 2 years: 10/16 (rituximab) vs 3/16 (placebo), P=.011
Mortality at 2 years: 0 deaths (rituximab) vs 6 deaths (placebo), P=.017
Severe infections: 2 (rituximab) vs 6 (placebo), P=.39 — not significant
Adverse events
Main adverse events: 8 severe infections total during follow-up: 6 in placebo arm and 2 in rituximab arm (P=.39, NS). No anaphylaxis to rituximab. Infusion-related reactions mild and manageable. Death rate significantly higher in placebo arm (6 vs 0 at 2 years), suggesting rituximab adds durable disease control with a favorable safety profile in elderly patients.
Conclusions
Rituximab combined with prednisone was significantly more effective than prednisone alone in achieving and maintaining response in first-line warm AIHA, with a mortality benefit at 2 years, supporting rituximab as part of standard first-line management.
Key Limitations
Key Limitations: Very small sample size (n=32), limiting statistical power and generalizability. Mean patient age was 71 years — primarily elderly population, which may not apply equally to younger patients. ITT analysis included all 32 randomized but only 27 followed for ≥1 year; missing data introduces bias. High placebo arm mortality (6 deaths) may reflect natural history of WAIHA in elderly rather than a rituximab-specific benefit. Open-label follow-up after the blinded phase could introduce assessment bias for response durability.
Clinical Context
RAIHA, together with the Birgens 2013 BJH trial, provides the randomized evidence supporting rituximab + corticosteroid as first-line therapy for warm AIHA. ASH 2023 guidelines recommend glucocorticoid + rituximab as first-line treatment in warm AIHA requiring therapy (conditional recommendation). In steroid-refractory or dependent warm AIHA, splenectomy, immunosuppressants (MMF, azathioprine), and novel agents (fostamatinib, rilzabrutinib) are being evaluated. B-cell depletion by rituximab addresses the autoimmune pathophysiology more directly than steroids alone.
References