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    Oral Communication Session

    Hemophilia and Rare Bleeding Disorders

    Management of Acquired Bleeding

    OC 06.2 - Emicizumab for Acquired Hemophilia A - A Case Series

    Saturday, June 24, 2023
    13:15 – 13:30 ET
    Room: 510
    Session Available As: On-Demand
    Background: The bispecific monoclonal antibody emicizumab is approved for bleeding prophylaxis in hemophilia A. However, no randomized trials addressed the efficacy of emicizumab in acquired hemophilia A (AHA), an autoantibody-mediated factor VIII (FVIII) deficiency.

    Aims: To report the clinical and biochemical response of emicizumab in AHA patients.

    Methods: This Belgian single-center retrospective study included seven adults diagnosed with AHA between November 2020 and May 2022. We collected patient characteristics, use of hemostatic agents, and bleeding and thrombotic events. Treatment response was monitored using chromogenic FVIII assays. Chromogenic assays with human reagents (FVIII:h) measure the combined emicizumab FVIII-like-activity and native patient FVIII-activity. As emicizumab does not bind to bovine reagents (FVIII:b), FVIII:b only assesses the patients’ native FVIII-activity.

    Results: Patient characteristics are summarized in table 1. AHA patients presented with spontaneous hematoma (n=7), intramuscular bleeding (n=2), hematuria (n=2) or gastro-intestinal bleeding (n=2). Six patients (86%) had major bleedings (ISTH criteria). At diagnosis, APTT was prolonged (90.8 seconds, IQR 72.5-103), FVIII activity was 0% (IQR 0-1) and FVIII inhibitor was 182 BU (IQR 104-228). All patients received emicizumab (3mg/kg) weekly for four weeks and every two weeks after the first month of treatment. Three patients (43%) received eptacog-alpha (cumulative dose of 140mg, IQR 106-174.5). All bleedings were stabilized after treatment start, without further bleeds. Patients reached FVIII:h ≥5% 12 days (IQR 7-14) after starting emicizumab (figure 1). As a result of immunosuppressive therapy, recovery of the intrinsic FVIII-activity (FVIII:b) was noted around day 100 coinciding with the disappearance of the FVIII inhibitor. There were no safety issues associated with emicizumab.

    Conclusion(s): In this case series, emicizumab was an effective hemostatic agent in AHA in conjunction with standard immunosuppressive therapy.

    Learning Objectives:

    • Upon completion, participants will be able to discuss options for hemostatic support of patients with acquired hemophilia A.
    • Upon completion, participants will be able to understand the effects of emicizumab on laboratory evaluation of factor VIII activity in patients with acquired hemophilia A.
    • Upon completion, participants will be able to gain insight into the early experience on the clinical course of patients with acquired hemophilia A treated with emicizumab.