Immunosuppression Therapy in Acquired Hemophilia A: Pursuing an Optimal Regimen

Acquired hemophilia A (AHA) is a rare bleeding disorder occurring mostly in elderly persons, caused by inhibition of factor VIII (FVIII). It is generally detected prior to surgery by an isolated prolonged activated partial thromboplastin time (aPTT) not correcting on mixing studies, with subsequent identification of reduced FVIII levels and presence of FVIII inhibitor. It is treated with hemostatics and immunosuppressants, which may increase the risk for life-threatening opportunistic infections. A 79-year-old woman with idiopathic acquired FVIII inhibition and severe bleeding presented with anemia, isolated and prolonged aPTT, low FVIII activity (<1%), and elevated FVIII inhibitor titer (471 Bethesda units per milliliter [BU/mL]). Initially, she was treated with recombinant activated factor VII and steroids. However, several hematomas appeared, one of which caused airway compression that required orotracheal intubation. Cyclophosphamide, rituximab (RTX), and activated prothrombin complex concentrate were initiated, resulting in clinical and laboratory resolution after five weeks. Cyclophosphamide and RTX were maintained for six and four weeks more, respectively. After 12 weeks of oral immunosuppression, the patient was readmitted due to antibiotic-resistant Pseudomonas aeruginosa sepsis, which resulted in death. Infection secondary to immunosuppression is the leading cause of death of patients with AHA. In AHA, combination therapy was shown to be more effective than monotherapy, but it was also identified to increase the risk of infection. Age, FVIII activity <1%, and FVIII inhibitor titers >20 BU are predictors of adverse events and poor prognosis in AHA patients. Additional studies are needed to clarify the ideal drug regimens and the need for prophylactic antibiotics in this population.