Background: Emicizumab is a newly FDA approved antibody for bleeding prophylaxis in congenital hemophilia A (CHA) with or without inhibitors. Acquired hemophilia A (AHA) is a rare form of hemophilia A where antibodies against endogenous factor VIII develops, resulting in a phenotype similar to CHA with inhibitors. Current guidelines on hemostatic agents in AHA recommends use of recombinant factor VIIa and replacement factor VIII. Given the shared pathophysiology between CHA with inhibitors and AHA, we hypothesize that there may be clinical evidence supporting the use of emicizumab in AHA.  

Aims: perform a systematic literature search of all available evidence on the use of emicizumab in AHA in a clinical setting and assess its efficacy as a prophylactic and hemostatic agent.

Methods: Flow diagram of the literature search of the literature

The scoping review was conducted following the PRISMA-P protocol. The search strategy was designed in consultation with a medical librarian to capture the widest scope of available evidence in Ovid MEDLINE, Embase and Web of Science, excluding only non-clinical study types. Title and abstract screening were performed by two independent reviewers followed by data extraction with a pre-determined extraction form.

Results: Summary of study details and population characteristics. *This was the case series and only the mean and range of the patient data was reported. BU = Bethesda units.

407 journal articles were identified in the initial search. After screening, four case reports and one case series totaling five studies were included in data extraction. Four males and four females totaling eight patients with a mean age of 64 were included in this review. All patients had severe AHA with high titer FVIII inhibitors and FVIII activity below 1%. All patients received emicizumab after achieving initial hemostasis with replacement or bypass therapy. Additional data on outcomes will be presented at the conference.

Conclusions: Our findings suggest there is limited clinical evidence of emicizumab prophylaxis in AHA based on a few case reports, demonstrating an important knowledge gap for this area. Additional research and guidelines are needed to guide clinical care.

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ISTH Congress Abstracts - https://abstracts.isth.org/abstract/emicizumab-in-acquired-hemophilia-a-a-scoping-review/