PB1199 - Acquired Hemophilia A: a single center experience.

Background: Acquired hemophilia A (AHA) is a rare bleeding disorder characterized by autoantibodies against factor VIII (FVIII), presenting substantial challenges in management due to its unpredictable nature. Understanding the demographic and clinical profiles, laboratory parameters, and treatment outcomes of AHA is crucial for improving patient care and advancing therapeutic strategies in the face of this complex and often life-threatening condition.

Aims: This study presents a comprehensive case series of AHA patients treated at McMaster University Hemophilia treatment center (HTC) in Ontario, Canada, between 2018 and 2023.

Methods: We performed a systematic review of electronic health records and compiled data on demographics, comorbidities, laboratory parameters, bleeding manifestations, and treatments

Results: Seventeen new AHA cases were identified from January 2018 to December 2023. Females constituted 59%, with a median age of 79 years (range: 34-86). Underlying conditions included malignancy (29%) and autoimmune disorders (24%). Median diagnostic APTT was 86 seconds (range: 55-200), with inhibitor titers median 33 BU (1.6 to 230 BU). All patients received immune suppressive therapy (IST); 65% used hemostatic agents, and 29% were treated with emicizumab. Table 1 Bleeding manifestations varied, with muscle bleeds (27%) and bruising (33%) being most common. Remission after first-line therapy was achieved in 29%, while 18% showed no remission. Twelve percent died during treatment, and relapse occurred in 29%. An apparent increase in new cases was observed over the last two years (Figure 1)

Conclusion(s): In this case series we reported the clinical and laboratory features of patients with AHA treated at McMaster University HTC. Emicizumab has been used in a significant proportion of patients and is emerging as a new potential strategy in AHA management. Further research is needed to understand evolving trends and optimize therapeutic approaches for enhanced patient management and prognosis.