Long-term outcome of haemophilia A patients after successful immune tolerance induction therapy using a single plasma-derived FVIII/VWF product: the long-term ITI study.

INTRODUCTION: Immune tolerance induction (ITI) is a standard intervention to eradicate inhibitors in haemophilic patients. However, information on the long-term condition of patients who eradicated the inhibitor totally or partially after ITI is scarce. AIM: To perform a long-term follow-up to describe the status of patients reported as ITI success in the G-ITI study. METHODS: This was an international, multicentre, observational, retrospective study of the 57 haemophilic patients who were reported as ITI success in the G-ITI study. Demographics and post-ITI clinical data recorded until January 2015 were extracted from the medical records. A descriptive analysis was undertaken. RESULTS: Forty-four patients were evaluable. Post-ITI follow-up was 9.1 years in average. Thirty-seven target joints were affected in 21 patients; 38 patients presented bleeding with a mean of 1.0 ± 1.2 episodes year-1 , most of them (271/330) treated with Fanhdi® (Grifols). Around half of the patients underwent at least one surgical procedure. Most venous access complications were of expected nature, requiring hospital stay in practically all cases. Fanhdi was used in 42 patients as the regular haemophilia treatment after ITI, mainly prophylactically. Three patients (6.8%) who were being treated with Fanhdi (prophylaxis), Kogenate (prophylaxis) and Emoclot (on demand), respectively, showed inhibitor relapse (at 29, 53 and 13 months after ITI, with 0.9, 3.65 and 12.5 BU respectively). All of them were successfully tolerized after rescue ITI. CONCLUSION: After ITI success, all patients continued with regular successful FVIII treatment for haemophilia for more than 9 years. The few inhibitor relapses were successfully overcome after rescue ITI.

Primary and rescue immune tolerance induction in children and adults: a multicentre international study with a VWF-containing plasma-derived FVIII concentrate.

Most studies on immune tolerance induction (ITI) therapy in haemophilia A patients are focused on primary ITI in children. Here we report on the ITI outcome in a large retrospective cohort, including adults and patients with rescue ITI, treated with a pdFVIII/VWF concentrate. Retrospective data from haemophilic patients (FVIII< 2%) with inhibitors from 22 centres in Spain, Italy and Germany, who underwent primary or rescue ITI with pdFVIII/VWF concentrate, were collected. Complete success (CS), partial success (PS) and failure were defined based on the criteria of the consensus recommendations of the 2006 International ITI Workshop. A total of 41 cases of primary ITI (32 children and 9 adults) and 19 cases of rescue ITI (17 children and 2 adults) were evaluated. Success (CS+PS) rate of 87% was achieved in primary ITI and 74% in the higher risk profile of rescue ITI. Eight of nine (85%) patients with poorest prognosis (three or more of the known risk factors of poor response to ITI) achieved success (CS+PS). CS of 100% was observed in eight primary ITI patients with titre at start of ITI ≤2.5 BU and inhibitor peak ≤25 BU. The favourable response rates in primary and rescue ITI in children and in adult patients, even in the presence of poor prognostic factors, should be encouraged for broadening the indication of immune tolerance therapy in haemophilia A patients with inhibitors.