Clinical Experience with Emicizumab and Rituximab as First-Line Treatment in a Case Series of Acquired Hemophilia A

<b>Background:</b> Acquired hemophilia A (AHA) is a bleeding disorder caused by autoantibodies against coagulation factor VIII. Treatment includes controlling bleeding and eliminating the inhibitor. Emicizumab has been increasingly used to prevent bleeding in patients with AHA. Rituximab is used as a first-line immunosuppressive therapy (IST) for AHA, either in combination with corticosteroids in high-risk patients or as monotherapy in low-risk patients who cannot tolerate corticosteroids. However, evidence regarding concomitant emicizumab and rituximab as first-line treatment for AHA is limited. <b>Case presentations:</b> We present five cases of AHA diagnosed at a single institution. The first three high-risk AHA cases in the era before emicizumab resulted in poor outcomes due to bleeding (Cases 1 and 3) or infection (Case 2). The recent cases (Cases 4 and 5) were successfully treated with emicizumab and rituximab-containing IST without severe bleeding and infections. Since emicizumab effectively relieved pain in these patients, rehabilitation could be initiated promptly, resulting in earlier hospital discharge. Complete remission was achieved on Day 42 in Case 4 and on Day 22 in Case 5, respectively, and emicizumab was subsequently discontinued in both cases. <b>Conclusions:</b> Our case series suggests that early initiation of emicizumab for patients with AHA is effective in preventing severe bleeding and subsequent immobility, and it can be combined with rituximab-containing IST to achieve remission, potentially with fewer adverse effects than standard IST. Further studies are warranted to establish the optimal treatment protocol involving emicizumab and IST for AHA.