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Despite significant ABR/AJBR reduction in all 3 groups, the efficacy of the primary prophylaxis was better than the secondary and tertiary prophylaxes.

Background In developing countries, children with hemophilia A (HA) with high‐titer inhibitor and poor immune tolerance induction (ITI) prognostic risk(s) cannot afford the recommended high‐ or intermediate‐dose ITI. Objectives To determine the efficacy of low‐dose ITI (plasma‐derived factor VIII [FVIII]/von Willebrand factor at 50 FVIII IU/kg every other day) by itself (ITI‐alone) or combined with immunosuppressants rituximab and prednisone (ITI‐IS) in children with HA with high‐titer inhibitor. Methods All enrolled patients had pre‐ITI inhibitor ≥10 BU. We used ITI‐alone if inhibitor titer was <40 BU pre‐ITI and during ITI, and ITI‐IS if titer was ≥100 BU (historic) or ≥40 BU (pre‐ or during ITI) or if the patient was nonresponsive on ITI‐alone. Results Fifty‐six children were analyzable, with median historic peak inhibitor titer 48.0 BU and followed for median 31.4 months. Overall, 35 (62.5%) achieved phase 2 success with negative inhibitor and normal FVIII recovery. The phase 2 success rate was 95% for the 20 patients receiving ITI‐alone. For the 36 patients receiving ITI‐IS, the phase 2 success rate was 44.4%, but would increase to 63.6% if the 14 patients with historic peak inhibitor titer ≥100 BU (and having phase 2 success rate of only 14.3%) were excluded. One patient developed repeated infection after IS treatment. Relapse occurred in 11.4% (4/35) patients with phase 2 success associated with rapid ITI dose reduction or irregular post‐ITI FVIII prophylaxis. Our strategy reduced the cost from high‐dose ITI by 74% to 90%. Conclusion The use of low‐dose ITI with or without immunosuppressants according to ITI prognostic risk(s) is a clinically and economically feasible strategy for eradicating inhibitors in children with HA, particularly for those with historic peak inhibitor titer <100 BU.

Introduction: Development of haemophilia B inhibitors (HBI) results in the ineffectiveness of FIX replacement therapy. Inhibitor eradication by immune tolerance induction (ITI) is therefore necessary. In HBI, ITI even at high FIX dose is less effective and has a higher risk of severe complications. Aim: To characterize clinical features and outcome of ITI on HBI. Methods: This retrospective study was conducted in Haemophilia Paediatric Comprehensive Care Centre of China. We used low-dose ITI (25-50 FIX IU/kg/three-timesweekly to every-other-day) with domestic prothrombin complex concentrate (PCC), combined with two successive immunosuppressive (IS) regimens.Results: Sixteen HBI children, representing 5.7% of all and 14.4% of our severe registered HB patients, were enroled. Seven cases reported allergic reactions (ARs) proximal to inhibitor development. The historic peak inhibitor titre was median 54.2 (range 4.7-512) BU, and 15 (93.8%) had high-titre inhibitors. Twelve patients adherent to ITI were analysable. Of the nine ITI patients who received rituximab/prednisone (IS Regimen-1), four achieved tolerization in 1.4-43.3 months. Two subsequently relapsed but re-tolerized after a second course of IS Regimen-1. During ITI, the median treated bleed was .39/month (82.7% reduction from before ITI), and the incidence of AR and nephrotic syndrome (NS) complications was each at 22% (2/9). Three ITI patients