A cquired hemophilia A (AHA), a rare bleeding disorder caused by neutralizing autoantibodies against coagulation factor VIII (FVIII), occurs in both men and women without a previous history of bleeding. Patients typically present with an isolated prolonged activated partial thromboplastin time due to FVIII deficiency. Neutralizing antibodies (inhibitors) are detected using the Nijmegen-modified Bethesda assay. Approximately 10% of patients do not present with bleeding and, therefore, a prolonged activated partial thromboplastin time should never be ignored prior to invasive procedures. Control of acute bleeding and prevention of injuries that may provoke bleeding are top priorities in patients with AHA. We recommend treatment with bypassing agents, including recombinant activated factor VII, activated prothrombin complex concentrate, or recombinant porcine FVIII in bleeding patients. Autoantibody eradication can be achieved with immunosuppressive therapy, including corticosteroids, cyclophosphamide and rituximab, or combinations thereof. The median time to remission is 5 weeks, with considerable interindividual variation. FVIII activity at presentation, inhibitor titer and autoantibody isotype are prognostic markers for remission and survival. Comparative clinical studies to support treatment recommendations for AHA do not exist; therefore, we provide practical consensus guidance based on recent registry findings and the authors' clinical experience in treating patients with AHA.

Identifying haemophilia patients with inhibitors for clinical trials is difficult due to the limited number of patients available. Registries are therefore being established as an additional means of data collection. The aim of this study was to investigate the effect of different recombinant activated factor VII (rFVIIa; NovoSeven dose ranges and dosing schedules on the incidence of re-bleeding in haemophilia patients with inhibitors. In this retrospective, uncontrolled study, data on the bleeding patterns of adult haemophilia patients with high responding inhibitors were analysed. Only data from the Czech Republic, obtained by the HemoRec registry, were used. This study analysed 'real-life' clinical data and focused on the collection of the same parameters in different patients: time from bleeding onset to first injection, effect of first injection, number of re-bleedings, total number of injections and total amount of haemostatic drug used. Fifteen patients met the inclusion criteria and were included into the study (128 bleeding episodes). Patients treated within 2 h of bleeding onset experienced less re-bleeding than patients treated after 2 h of bleeding onset (5.2% vs. 13.7%, respectively). In addition, patients who were treated after 2 h of bleeding onset experienced fewer re-bleedings when high-dose rFVIIa was used (15.8% and 0%; <120 microg kg(-1) and >250 microg kg(-1), respectively). Initial high-dose rFVIIa was also associated with a decline in total rFVIIa consumption. This registry has provided a unique insight into the bleeding patterns of inhibitor patients, highlighting the importance of early treatment initiation and appropriate starting dose.

No abstract

Summary. Development of inhibitors is a severe complication of haemophilia posing many management challenges. While a long-term goal in inhibitor patients is eradication of inhibitors through immune tolerance induction, bypassing agents such as recombinant activated factor VII (rFVIIa) and activated prothrombin complex concentrate (aPCC) are essential for control of bleeding episodes. Paediatric patients with haemophilia and inhibitors are at particular risk of recurrent haemarthroses, and management of these patients should seek to avoid joint damage and support the child's full social and physical development. Current options for management of bleeding complications include on-demand treatment of acute bleeding episodes, secondary prophylaxis to avoid recurrent bleeds and surgery to treat affected joints. There is also a rationale for adopting prophylactic approaches to prevent bleeding in inhibitor patients, allowing this group similar opportunities for protection against arthropathy development as are given to non-inhibitor patients. This paper, based on a roundtable meeting of haematology experts at the first Zü rich Haemophilia Forum in May 2008, reviews the current evidence supporting more intense and prophylactic approaches to manage bleeding risk in paediatric haemophilia patients with inhibitors, and highlights the need for investigations of primary prophylaxis in this vulnerable patient group, to support best longterm outcome.

No abstract