Real-World Data Of Immune Tolerance Induction Using Rfviiifc In Subjects With Severe Hemophilia A With Inhibitors At High Risk For Iti Failure

Introduction: Immune tolerance induction (ITI) is the standard of care for eradication of inhibitors in subjects with severe hemophilia A. ITI is not always effective and can require a lengthy and burdensome treatment regimen. Those who have previously failed ITI are more likely to fail subsequent ITI. The successful use of recombinant factor VIII Fc fusion protein (rFVIIIFc) for ITI was described in our initial retrospective review of 19 high-risk subjects, including first-time and rescue ITI subjects (Carcao et al, Haemophilia, 2018). These findings indicated that time to tolerization appears to be faster with rFVIIIFc, despite a high-risk profile. It has been postulated that the Fc domain of rFVIIIFc may promote tolerization due to immunomodulatory properties. We report characteristics and ITI outcomes of 6 newly identified subjects, as well as follow-up data from 12 of the 19 subjects included in the original analysis.