OC 06.5 - Use of Emicizumab for the treatment of Acquired Hemophilia A: A Systematic Review

Background: Acquired Hemophilia A (AHA) is a rare disease that occurs due to the development of antibodies against FVIII, leading to severe bleeding complications with high morbidity and mortality. Emicizumab is a bispecific, monoclonal antibody that bridges activated factor IX (FIXa) and X (FX). It has shown to be effective in achieving hemostatic control in people with hemophilia A with FVIII inhibitors. Thus, it has been used off-label in the management of AHA.

Aims: We conducted a systematic review on the use of Emicizumab for the treatment of AHA, focusing on the time required to achieve bleeding control.

Methods: We conducted a comprehensive search in PubMed, EMBASE, Medline and The Cochrane Library from inception until January, 2023. Studies reporting cases of patients diagnosed with AHA that received at least one dose of emicizumab were included (Figure 1)

Results: Eighteen studies were included in the final review for a total of 45 patients. The median age was 78 years (range: 21 – 93). The vast majority (75.6%) were males. Presenting bleeding symptoms were widely variable; the most common were subcutaneous bleeding and muscle hematomas. In forty patients the FVIII levels at diagnosis were ≤ 1% or undetectable. The median inhibitor level was 40 BU/mL (1.8 to 2000 BU/mL). Kaplan-Meier analysis showed that around 56% of patients have been reported to achieve bleed control in one day after the start of treatment and almost 90% of patients had no bleeding by day 5 of starting Emicizumab (Figure 2). Side effects were infrequently reported; nevertheless, the treatment appeared to be well-tolerated.

Conclusion(s): Emicizumab appears to be an effective and safe hemostatic treatment for AHA. Bleeding control is rapidly achieved after initiating emicizumab. Clinical trials comparing emicizumab versus standard hemostatic agents are needed to confirm these findings.