Treatment of the bleeding inhibitor patient.

The development of inhibitory antibodies to factor (F) VIII and FIX continues to be a major challenge in the treatment of patients with hemophilia. In patients with low-responding inhibitors, it is usually possible to saturate the inhibitor with the deficient factor and to achieve hemostasis, but in patients with high-responding inhibitors, two major tasks have to be considered. One is how to treat the acute bleedings and the other is how to permanently eliminate the immune response, in other words, to induce tolerance. There are several hemostatic agents available for bleeding patients with high-responding inhibitors. Nonactivated and activated prothrombin complex concentrates (PCCs) have been used for almost 30 years, and since the beginning of the 1980s, porcine FVIII has also been used. In more recent years, recombinant FVIIa has been added to the therapeutic armamentarium and has been shown to control hemostasis in most patients. Immunoadsorption may temporarily reduce the inhibitor, enabling replacement therapy for several days. Available data on these alternative regimens will be discussed with a focus on the mechanisms of action, pharmacokinetics, safety, monitoring, and clinical experience.