Emicizumab Prophylaxis in Patients with Hemophilia A Undergoing Immune Tolerance Induction Therapy: A Systematic Review

Objective: The use of Emicizumab, a novel agent in hemophilia A, in patients with Hemophilia A undergoing immune tolerance induction (ITI) have been currently evolving in overseas. Here, we aimed to evaluate the real-world use and conceptual study of emicizumab use during ITI in patients with Hemophilia A. Methods: We searched PubMed, Embase, and Cochrane Library databases to perform systematic review according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA). Search terms include ‘hemophilia‘, ‘immune tolerance and ‘Emicizumab’. Hemophilia other than hemophilia A, studies with no relevant outcomes, emicizumab use other than during ITI were excluded. Results: Among 419 relevant studies, ten eligible studies were included in this review. Six studies reported real-world prophylactic use of emicizumab during ITI, and total of nineteen subjects, including overlapping patients, were evaluated. Other four studies reported conceptual study design of emicizumab in patients with hemophilia A undergoing ITI. Majority of study set the dose of emicizumab as 1.5mg/kg weekly or 3.0mg/kg bi-weekly after a loading dose of 3.0mg/kg for 4 weeks. In real-world prophylactic use studies, ITI outcome, inhibitor recurrence, antibody titer, adverse events, and FVIII activity were evaluated as outcomes. Conclusion: This study identified the current status of emicizumab use and made evidence for the applicability of emicizumab in patients with hemophilia A undergoing ITI.