PB1844 SUCCESSFUL TREATMENT OF 5 PATIENTS WITH ACQUIRED HEMOPHILIA WITH HIGH INHIBITOR TITER ‐ SINGLE CENTER SURVEY

Background: Acquired hemophilia A (AHA) is a rare, severe and potentially life treating bleeding disorder. It is caused by the spontaneously formed autoantibodies, which are polyclonal immunoglobulins, usually IgG directed against the FVIII. While this disorder may appear at any age, the elderly are most commonly affected. It is associated with autoimmune diseases, malignancies and pregnancy, although approximately 50% of cases are idiopathic. Patients may present with overt bleeding (hemorrhages into the skin, muscles or soft tissues and mucous membranes) or anemia due to occult hemorrhage. Treatment goals for AHA are: comprise hemostasis, inhibitor eradication and treatment of associated disorders. The mortality rate is relatively high, ranging from 6% to 8% due to extensive bleeding, elderly life, side effects and toxicity of immunosuppressive agents and concomitant diseases. Aims: In this study, we wanted to evaluate the clinical characteristics, treatment efficiency and outcome of patients with AHA. Methods: The retrospective study investigated cases of AHA at the Clinic for Hematology, Clinical Centre of Vojvodina, Serbia, from March 2016 to December 2018. We evaluated 5 patients with AHA managed at our Haemophilia Centre. Results: Out of our five patients, three were males and two females, age ranging between 44 and 88 years (mean age 67.8 years). No one had a history of previous bleeding episodes. Four had mild clinical manifestations of the disease; subcutaneous hemorrhage and soft tissue bleeds localized at the extremities, while one patient presented with massive iliopsoas muscle hematoma and upper gastrointestinal bleeding. In one patient inhibitors were associated with double malignancies (CLL, lung cancer), and in another patient with paraproteinaemia. Three patients had comorbidities including coronary artery disease, arterial hypertension, COPD and diabetes mellitus type 2. Osteoarthritis was diagnosed at one patient. The youngest patient had no associated disease or underlying medical conditions and only he did not have anemia. Activated partial thromboplastin time (aPTT) was prolonged in all patients (range 29.8 ‐ 90.1 s). In every patient low level of FVIII activity has been found. It was ranging from <1.0% to 12.0% (mean 2.69%). All bleeding episodes resolved with hemostatic replacement therapy, activated prothrombin complex concentrate ‐ APCC (FEIBA®) (n‐3), APCC plus recombinant activated factor VII ‐ rFVIIa (NovoSeven®) (n‐2). In our review all the patients had high‐titre of inhibitors (> 5 BU/mL). The mean peak was 46.8 BU/mL (range 8.3‐185). To eradicate the inhibitors, all patients received systemic corticosteroids, either alone (n‐2) or in combination with cyclophosphamide (n‐3). In all patients, management was successful, with complete response (CR) within 2 months of treatment initiation. Only one patient, with the highest titre of inhibitors, relapsed after 2 months. All of the other patients were in remission over the 2 years of follow‐up. One patient died of lung cancer complications within 2 months at AHA diagnosis. Summary/Conclusion: Most of our patients were elderly patients. All of them had high titers of inhibitors and all achieved long ‐ term CR after immunosuppressive therapy, despite cancer progression in one patient. Our study showed variable clinical presentations and AHA severity. By passing agents are efficient in treating bleeding episodes in AHA patients. In our study overall survival depended on comorbidities not on AHA.